18F-FDG PET/CT and radiolabeled leukocyte SPECT/CT imaging for the evaluation of cardiovascular infection in the multimodality context: ASNC Imaging Indications (ASNC I2) Series Expert Consensus Recommendations from ASNC, AATS, ACC, AHA, ASE, EANM, HRS, IDSA, SCCT, SNMMI, and STS

This document on cardiovascular infection, including infective endocarditis, is the first in the American Society of Nuclear Cardiology Imaging Indications (ASNC I2) series to assess the role of radionuclide imaging in the multimodality context for the evaluation of complex systemic diseases with multi-societal involvement including pertinent disciplines. A rigorous modified Delphi approach was used to determine consensus clinical indications, diagnostic criteria, and an algorithmic approach to diagnosis of cardiovascular infection including infective endocarditis. Cardiovascular infection incidence is increasing and is associated with high morbidity and mortality. Current strategies based on clinical criteria and an initial echocardiographic imaging approach are effective but often insufficient in complicated cardiovascular infection. Radionuclide imaging with 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (CT) and single photon emission computed tomography/CT leukocyte scintigraphy can enhance the evaluation of suspected cardiovascular infection by increasing diagnostic accuracy, identifying extracardiac involvement, and assessing cardiac implanted device pockets, leads, and all portions of ventricular assist devices. This advanced imaging can aid in key medical and surgical considerations. Consensus diagnostic features include focal/multi-focal or diffuse heterogenous intense 18F-FDG uptake on valvular and prosthetic material, perivalvular areas, device pockets and leads, and ventricular assist device hardware persisting on non-attenuation corrected images. There are numerous clinical indications with a larger role in prosthetic valves, and cardiac devices particularly with possible infective endocarditis or in the setting of prior equivocal or non-diagnostic imaging. Illustrative cases incorporating these consensus recommendations provide additional clarification. Future research is necessary to refine application of these advanced imaging tools for surgical planning, to identify treatment response, and more.

Thin slice photon-counting CT coronary angiography compared to conventional CT: Objective image quality and clinical radiation dose assessment

BACKGROUND

Photon-counting CT (PCCT) is the next-generation CT scanner that enables improved spatial resolution and spectral imaging. For full spectral processing, higher tube voltages compared to conventional CT are necessary to achieve the required spectral separation. This generated interest in the potential influence of thin slice high tube voltage PCCT on overall image quality and consequently on radiation dose.

PURPOSE

This study first evaluated tube voltages and radiation doses applied in patients who underwent coronary CT angiography with PCCT and energy-integrating detector CT (EID-CT). Next, image quality of PCCT and EID-CT was objectively evaluated in a phantom study simulating different patient sizes at these tube voltages and radiation doses.

METHODS

We conducted a retrospective analysis of clinical doses of patients scanned on a conventional and PCCT system. Average patient water equivalent diameters for different tube voltages were extracted from the dose reports for both EID-CT and PCCT. A conical phantom made of polyethylene with multiple diameters (26/31/36 cm) representing different patient sizes and containing an iodine insert was scanned with a EID-CT scanner using tube voltages and phantom diameters that match the patient scans and characteristics. Next, phantom scans were made with PCCT at a fixed tube voltage of 120 kV and with CTDIVOL values and phantom diameters identical to the EID-CT scans. Clinical image reconstructions at 0.6 mm slice thickness for conventional CT were compared to PCCT images with 0.4 mm slice thickness. Image quality was quantified using the detectability index (d'), which estimated the visibility of a 3 mm diameter contrast-enhanced coronary artery by considering noise, contrast, resolution, and human visual perception. Alongside d', noise, contrast and resolution were also individually assessed. In addition, the influence of various kernels (Bv40/Bv44/Bv48/Bv56), quantum iterative reconstruction strengths (QIR, 3/4) and monoenergetic levels (40/45/50/55 keV) for PCCT on d' was investigated.

RESULTS

In this study, 143 patients were included: 47 were scanned on PCCT (120 kV) and the remaining on EID-CT (74 small-sized at 70 kV, 18 medium-sized at 80 kV and four large-sized at 90 kV). EID-CT showed 7%-17% higher d' than PCCT with Bv40 kernel and strength four for small/medium patients. Lower monoenergetic images (40 keV) helped mitigate the difference to 1%-6%. For large patients, PCCT's detectability was up to 31% higher than EID-CT. PCCT has thinner slices but similar noise levels for similar reconstruction parameters. The noise increased with lower keV levels in PCCT (≈30% increase), but higher QIR strengths reduced noise. PCCT's iodine contrast was stable across patient sizes, while EID-CT had 33% less contrast in large patients than in small-sized patients.

CONCLUSION

At 120 kV, thin slice PCCT enables CCTA in phantom scans representing large patients without raising radiation dose or affecting vessel detectability. However, higher doses are needed for small and medium-sized patients to obtain a similar image quality as in EID-CT. The alternative of using lower mono-energetic levels requires further evaluation in clinical practice.

18F-FDG PET/CT and radiolabeled leukocyte SPECT/CT imaging for the evaluation of cardiovascular infection in the multimodality context: ASNC Imaging Indications (ASNC I2) Series Expert Consensus Recommendations from ASNC, AATS, ACC, AHA, ASE, EANM, HRS, IDSA, SCCT, SNMMI, and STS

This document on cardiovascular infection, including infective endocarditis, is the first in the American Society of Nuclear Cardiology Imaging Indications (ASNC I2) series to assess the role of radionuclide imaging in the multimodality context for the evaluation of complex systemic diseases with multi-societal involvement including pertinent disciplines. A rigorous modified Delphi approach was used to determine consensus clinical indications, diagnostic criteria, and an algorithmic approach to diagnosis of cardiovascular infection including infective endocarditis. Cardiovascular infection incidence is increasing and is associated with high morbidity and mortality. Current strategies based on clinical criteria and an initial echocardiographic imaging approach are effective but often insufficient in complicated cardiovascular infection. Radionuclide imaging with 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (CT) and single photon emission computed tomography/CT leukocyte scintigraphy can enhance the evaluation of suspected cardiovascular infection by increasing diagnostic accuracy, identifying extracardiac involvement, and assessing cardiac implanted device pockets, leads, and all portions of ventricular assist devices. This advanced imaging can aid in key medical and surgical considerations. Consensus diagnostic features include focal/multi-focal or diffuse heterogenous intense 18F-FDG uptake on valvular and prosthetic material, perivalvular areas, device pockets and leads, and ventricular assist device hardware persisting on non-attenuation corrected images. There are numerous clinical indications with a larger role in prosthetic valves, and cardiac devices particularly with possible infective endocarditis or in the setting of prior equivocal or non-diagnostic imaging. Illustrative cases incorporating these consensus recommendations provide additional clarification. Future research is necessary to refine application of these advanced imaging tools for surgical planning, to identify treatment response, and more.

18F-FDG PET/CT and radiolabeled leukocyte SPECT/CT imaging for the evaluation of cardiovascular infection in the multimodality context: ASNC Imaging Indications (ASNC I2) Series Expert Consensus Recommendations from ASNC, AATS, ACC, AHA, ASE, EANM, HRS, IDSA, SCCT, SNMMI, and STS

This document on cardiovascular infection, including infective endocarditis, is the first in the American Society of Nuclear Cardiology Imaging Indications (ASNC I2) series to assess the role of radionuclide imaging in the multimodality context for the evaluation of complex systemic diseases with multi-societal involvement including pertinent disciplines. A rigorous modified Delphi approach was used to determine consensus clinical indications, diagnostic criteria, and an algorithmic approach to diagnosis of cardiovascular infection including infective endocarditis. Cardiovascular infection incidence is increasing and is associated with high morbidity and mortality. Current strategies based on clinical criteria and an initial echocardiographic imaging approach are effective but often insufficient in complicated cardiovascular infection. Radionuclide imaging with 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) and single photon emission computed tomography/CT leukocyte scintigraphy can enhance the evaluation of suspected cardiovascular infection by increasing diagnostic accuracy, identifying extracardiac involvement, and assessing cardiac implanted device pockets, leads, and all portions of ventricular assist devices. This advanced imaging can aid in key medical and surgical considerations. Consensus diagnostic features include focal/multi-focal or diffuse heterogenous intense 18F-FDG uptake on valvular and prosthetic material, perivalvular areas, device pockets and leads, and ventricular assist device hardware persisting on non-attenuation corrected images. There are numerous clinical indications with a larger role in prosthetic valves, and cardiac devices particularly with possible infective endocarditis or in the setting of prior equivocal or non-diagnostic imaging. Illustrative cases incorporating these consensus recommendations provide additional clarification. Future research is necessary to refine application of these advanced imaging tools for surgical planning, to identify treatment response, and more.

18F-FDG PET/CT and Radiolabeled Leukocyte SPECT/CT Imaging for the Evaluation of Cardiovascular Infection in the Multimodality Context: ASNC Imaging Indications (ASNC I2) Series Expert Consensus Recommendations From ASNC, AATS, ACC, AHA, ASE, EANM, HRS, IDSA, SCCT, SNMMI, and STS

This document on cardiovascular infection, including infective endocarditis, is the first in the American Society of Nuclear Cardiology Imaging Indications (ASNC I2) series to assess the role of radionuclide imaging in the multimodality context for the evaluation of complex systemic diseases with multi-societal involvement including pertinent disciplines. A rigorous modified Delphi approach was used to determine consensus clinical indications, diagnostic criteria, and an algorithmic approach to diagnosis of cardiovascular infection including infective endocarditis. Cardiovascular infection incidence is increasing and is associated with high morbidity and mortality. Current strategies based on clinical criteria and an initial echocardiographic imaging approach are effective but often insufficient in complicated cardiovascular infection. Radionuclide imaging with fluorine-18 fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (CT) and single photon emission computed tomography/CT leukocyte scintigraphy can enhance the evaluation of suspected cardiovascular infection by increasing diagnostic accuracy, identifying extracardiac involvement, and assessing cardiac implanted device pockets, leads, and all portions of ventricular assist devices. This advanced imaging can aid in key medical and surgical considerations. Consensus diagnostic features include focal/multi-focal or diffuse heterogenous intense 18F-FDG uptake on valvular and prosthetic material, perivalvular areas, device pockets and leads, and ventricular assist device hardware persisting on non-attenuation corrected images. There are numerous clinical indications with a larger role in prosthetic valves, and cardiac devices particularly with possible infective endocarditis or in the setting of prior equivocal or non-diagnostic imaging. Illustrative cases incorporating these consensus recommendations provide additional clarification. Future research is necessary to refine application of these advanced imaging tools for surgical planning, to identify treatment response, and more.

Competence of radiologists in cardiac CT and MR imaging in Europe: insights from the ESCR Registry

RATIONALE

To provide an overview of the current status of cardiac multimodality imaging practices in Europe and radiologist involvement using data from the European Society of Cardiovascular Radiology (ESCR) MRCT-registry.

MATERIALS AND METHODS

Numbers on cardiac CT and MRI examinations were extracted from the MRCT-registry of the ESCR, entered between January 2011 and October 2023 (n = 432,265). Data collection included the total/annual numbers of examinations, indications, complications, and reporting habits.

RESULTS

Thirty-two countries contributed to the MRCT-registry, including 29 European countries. Between 2011 and 2022, there was a 4.5-fold increase in annually submitted CT examinations, from 3368 to 15,267, and a 3.8-fold increase in MRI examinations, from 3445 to 13,183. The main indications for cardiac CT were suspected coronary artery disease (CAD) (59%) and transcatheter aortic valve replacement planning (21%). The number of patients with intermediate pretest probability who underwent CT for suspected CAD showed an increase from 61% in 2012 to 82% in 2022. The main MRI indications were suspected myocarditis (26%), CAD (21%), and suspected cardiomyopathy (19%). Adverse event rates were very low for CT (0.3%) and MRI (0.7%) examinations. Reporting of CT and MRI examinations was performed mainly by radiologists (respectively 76% and 71%) and, to a lesser degree, in consensus with non-radiologists (19% and 27%, respectively). The remaining examinations (4.9% CT and 1.7% MRI) were reported by non-radiological specialties or in separate readings of radiologists and non-radiologists.

CONCLUSIONS

Real-life data on cardiac imaging in Europe using the largest available MRCT-registry demonstrate a considerable increase in examinations over the past years, the vast majority of which are read by radiologists. These findings indicate that radiologists contribute to meeting the increasing demands of competent and effective care in cardiac imaging to a relevant extent.

CLINICAL RELEVANCE STATEMENT

The number of cardiac CT and MRI examinations has risen over the past years, and radiologists read the vast majority of these studies as recorded in the MRCT-registry.

KEY POINTS

• The number of cardiac imaging examinations is constantly increasing. • Radiologists play a central role in providing cardiac CT and MR imaging services to a large volume of patients. • Cardiac CT and MR imaging examinations performed and read by radiologists show a good safety profile.

Ultra-High-Resolution and K-Edge Imaging of Prosthetic Heart Valves With Spectral Photon-Counting CT: A Phantom Study

BACKGROUND AND PURPOSE

The contribution of cardiac computed tomography (CT) for the detection and characterization of prosthetic heart valve (PHV) complications is still limited due mainly to artifacts. Computed tomography systems equipped with photon-counting detectors (PCDs) have the potential to overcome these limitations. Therefore, the aim of the study was to compare image quality of PHV with PCD-CT and dual-energy dual-layer CT (DEDL-CT).

MATERIALS AND METHODS

Two metallic and 3 biological PHVs were placed in a tube containing diluted iodinated contrast inside a thoracic phantom and scanned repeatedly at different angles on a DEDL-CT and PCD-CT. Two small lesions (~2 mm thickness; containing muscle and fat, respectively) were attached to the structure of 4 valves, placed inside the thoracic phantom, with and without an extension ring, and scanned again. Acquisition parameters were matched for the 2 CT systems and used for all scans. Metallic valves were scanned again with parameters adapted for tungsten K-edge imaging. For all valves, different metallic parts were measured on conventional images to assess their thickness and blooming artifacts. In addition, 6 parallelepipeds per metallic valve were drawn, and all voxels with density <3 times the standard deviation of the contrast media were recorded as an estimate of streak artifacts. For subjective analysis, 3 expert readers assessed conventional images of the valves, with and without lesions, and tungsten K-edge images. Conspicuity and sharpness of the different parts of the valve, the lesions, metallic, and blooming artifacts were scored on a 4-point scale. Measurements and scores were compared with the paired t test or Wilcoxon test.

RESULTS

The objective analysis showed that, with PCD-CT, valvular metallic structures were thinner and presented less blooming artifacts. Metallic artifacts were also reduced with PCD-CT (11 [interquartile (IQ) = 6] vs 40 [IQ = 13] % of voxels). Subjective analysis allowed noticing that some structures were visible or clearly visible only with PCD-CT. In addition, PCD-CT yielded better scores for the conspicuity and for the sharpness of all structures (all Ps < 0.006), except for the conspicuity of the leaflets of the mechanical valves, which were well visible with either technique (4 [IQ = 3] for both). Both blooming and streak artifacts were reduced with PCD-CT (P ≤ 0.01). Overall, the use of PCD-CT resulted in better conspicuity and sharpness of the lesions compared with DEDL-CT (both Ps < 0.02). In addition, only with PCD-CT some differences between the 2 lesions were detectable. Adding the extension ring resulted in reduced conspicuity and sharpness with DEDL-CT (P = 0.04 and P = 0.02, respectively) and only in reduced sharpness with PCD-CT (P = 0.04). Tungsten K-edge imaging allowed for the visualization of the only dense structure containing it, the leaflets, and it resulted in images judged having less blooming and metallic artifacts as compared with conventional PCD-CT images (P < 0.01).

CONCLUSIONS

With PCD-CT, objective and subjective image quality of metallic and biological PHVs is improved compared with DEDL-CT. Notwithstanding the improvements in image quality, millimetric lesions attached to the structure of the valves remain a challenge for PCD-CT. Tungsten K-edge imaging allows for even further reduction of artifacts.

Image quality assessment of coronary artery segments using ultra-high resolution dual source photon-counting detector computed tomography

PURPOSE

The study is intended to assess the image quality of ultra-high resolution (UHR) coronary computed tomography angiography (CCTA) performed on dual source photon-counting detector CT (PCD-CT).

METHOD

Consecutive patients, who underwent clinically indicated CCTA on PCD-CT (UHR 120x 0.2 mm collimation), were included. CCTA images were reconstructed at 0.2 mm slice thickness with Bv40, Bv44, Bv48 and Bv56 kernels and quantum iterative reconstruction level 4. Contrast-to-noise (CNR) and signal-to-noise ratios (SNR) were quantified from contrast-enhanced blood and subcutaneous adipose tissue. All reconstructions were scored per coronary segment (18-segment model) for presence, image quality, motion artefacts, stack artefacts, plaque presence and composition, and stenosis degree. Image quality was scored by two independent observers.

RESULTS

Sixty patients were included (median age 62 [25th - 75th percentile: 53-67] years, 45% male, median calcium score 62 [0-217]). The mean heart rate during scanning was 71 ± 11 bpm. Median CTDIvol was 19 [16-22]mGy and median DLP 243 [198-327]mGy.cm. The SNR was 9.3 ± 2.3 and the CNR was 11.7 ± 2.6. Of the potential 1080 coronary segments (60 patients x 18 segments), 255/256 (reader1/reader2) segments could not be assessed for being absent or non-evaluable due to size. Both readers scored 85% of the segments as excellent or very good (Intraclass Correlation Coefficient: 0.88 (95% CI: 0.87-0.90). Motion artefacts were present in 45(5%) segments, stack artefacts in 60(7%) segments and metal artefacts in 9(1%) segments.

CONCLUSION

UHR dual-source PCD-CT CCTA provides excellent or very good image quality in 85% of coronary segments at relatively high heart rates at moderate radiation dose with only limited stack artefacts.

Quantitative metrics of the LV trabeculated layer by cardiac CT and cardiac MRI in patients with suspected noncompaction cardiomyopathy

OBJECTIVES

To compare cardiac computed tomography (CCT) and cardiac magnetic resonance (CMR) for the quantitative assessment of the left ventricular (LV) trabeculated layer in patients with suspected noncompaction cardiomyopathy (NCCM).

MATERIALS AND METHODS

Subjects with LV excessive trabeculation who underwent both CMR and CCT imaging as part of the prospective international multicenter NONCOMPACT clinical study were included. For each subject, short-axis CCT and CMR slices were matched. Four quantitative metrics were estimated: 1D noncompacted-to-compacted ratio (NCC), trabecular-to-myocardial area ratio (TMA), trabecular-to-endocardial cavity area ratio (TCA), and trabecular-to-myocardial volume ratio (TMV). In 20 subjects, end-diastolic and mid-diastolic CCT images were compared for the quantification of the trabeculated layer. Relationships between the metrics were investigated using linear regression models and Bland-Altman analyses.

RESULTS

Forty-eight subjects (49.9 ± 12.8 years; 28 female) were included in this study. NCC was moderately correlated (r = 0.62), TMA and TMV were strongly correlated (r = 0.78 and 0.78), and TCA had excellent correlation (r = 0.92) between CMR and CCT, with an underestimation bias from CCT of 0.3 units, and 5.1, 4.8, and 5.4 percent-points for the 4 metrics, respectively. TMA, TCA, and TMV had excellent correlations (r = 0.93, 0.96, 0.94) and low biases (- 3.8, 0.8,  - 3.8 percent-points) between the end-diastolic and mid-diastolic CCT images.

CONCLUSIONS

TMA, TCA, and TMV metrics of the LV trabeculated layer in patients with suspected NCCM demonstrated high concordance between CCT and CMR images. TMA and TCA were highly reproducible and demonstrated minimal differences between mid-diastolic and end-diastolic CCT images.

CLINICAL RELEVANCE STATEMENT

The results indicate similarity of CCT to CMR for quantifying the LV trabeculated layer, and the small differences in quantification between end-diastole and mid-diastole demonstrate the potential for quantifying the LV trabeculated layer from clinically performed coronary CT angiograms.

KEY POINTS

• Data on cardiac CT for quantifying the left ventricular trabeculated layer are limited. • Cardiac CT yielded highly reproducible metrics of the left ventricular trabeculated layer that correlated well with metrics defined by cardiac MR. • Cardiac CT appears to be equivalent to cardiac MR for the quantification of the left ventricular trabeculated layer.

Physical exercise and cardiovascular response: design and implementation of a pediatric CMR cohort study

To examine feasibility and reproducibility and to evaluate the cardiovascular response to an isometric handgrip exercise in low-risk pediatric population using Cardiovascular Magnetic Resonance measurements. In a subgroup of 207 children with a mean age of 16 years participating in a population-based prospective cohort study, children performed an isometric handgrip exercise. During rest and exercise, continuous heart rate and blood pressure were measured. Cardiovascular magnetic resonance (CMR) measurements included left ventricular mass, aortic distensibility and pulse wave velocity at rest and left ventricular end-diastolic and end-systolic volumes, ejection fraction, stroke volume and cardiac output during rest and exercise. 207 children had successful CMR measurements in rest and 184 during exercise. We observed good reproducibility for all cardiac measurements. Heart rate increased with a mean ± standard deviation of 42.6% ± 20.0 and blood pressure with 6.4% ± 7.0, 5.4% ± 6.1 and 11.0% ± 8.3 for systolic, diastolic and mean arterial blood pressure respectively (p-values < 0.05). During exercise, left ventricular end-diastolic and end-systolic volumes and cardiac output increased, whereas left ventricular ejection fraction slightly decreased (p-values < 0.05). Stroke volume did not change significantly. A sustained handgrip exercise of 7 min at 30-40% maximal voluntary contraction is a feasible exercise-test during CMR in a healthy pediatric population, which leads to significant changes in heart rate, blood pressure and functional measurements of the left ventricle in response to exercise. This approach offers great novel opportunities to detect subtle differences in cardiovascular health.

Coronary calcium scoring on virtual non-contrast and virtual non-iodine reconstructions compared to true non-contrast images using photon-counting computed tomography

OBJECTIVES

To compare coronary artery calcification (CAC) scores measured on virtual non-contrast (VNC) and virtual non-iodine (VNI) reconstructions computed from coronary computed tomography angiography (CCTA) using photon-counting computed tomography (PCCT) to true non-contrast (TNC) images.

METHODS

We included 88 patients (mean age = 59 years ± 13.5, 69% male) who underwent a TNC coronary calcium scan followed by CCTA on PCCT. VNC images were reconstructed in 87 patients and VNI in 88 patients by virtually removing iodine from the CCTA images. For all reconstructions, CAC scores were determined, and patients were classified into risk categories. The overall agreement of the reconstructions was analyzed by Bland-Altman plots and the level of matching classifications.

RESULTS

The median CAC score on TNC was 27.8 [0-360.4] compared to 8.5 [0.2-101.6] (p < 0.001) on VNC and 72.2 [1.3-398.8] (p < 0.001) on VNI. Bland-Altman plots depicted a bias of 148.8 (ICC = 0.82, p < 0.001) and - 57.7 (ICC = 0.95, p < 0.001) for VNC and VNI, respectively. Of all patients with CACTNC = 0, VNC reconstructions scored 63% of the patients correctly, while VNI scored 54% correctly. Of the patients with CACTNC > 0, VNC and VNI reconstructions detected the presence of coronary calcium in 90% and 92% of the patients. CACVNC tended to underestimate CAC score, whereas CACVNI overestimated, especially in the lower risk categories. According to the risk categories, VNC misclassified 55% of the patients, while VNI misclassified only 32%.

CONCLUSION

Compared to TNC images, VNC underestimated and VNI overestimated the actual CAC scores. VNI reconstructions quantify and classify coronary calcification scores more accurately than VNC reconstructions.

CLINICAL RELEVANCE STATEMENT

Photon-counting CT enables spectral imaging, which might obviate the need for non-contrast enhanced coronary calcium scoring, but optimization is necessary for the clinical implementation of the algorithms.

KEY POINTS

• Photon-counting computed tomography uses spectral information to virtually remove the signal of contrast agents from contrast-enhanced scans. • Virtual non-contrast reconstructions tend to underestimate coronary artery calcium scores compared to true non-contrast images, while virtual non-iodine reconstructions tend to overestimate the calcium scores. • Virtual non-iodine reconstructions might obviate the need for non-contrast enhanced calcium scoring, but optimization is necessary for the clinical implementation of the algorithms.

Scientific document development standards for the society of cardiovascular computed tomography (SCCT): A statement from the SCCT Guidelines Committee

The Society of Cardiovascular Computed Tomography (SCCT) is an international community of physicians, scientists and technologists advocating for research, education, and clinical excellence in the use of cardiovascular computed tomography (CCT). SCCT members are committed to improving health outcomes through effective use of CCT. The SCCT routinely authors, endorses, and jointly collaborates on scientific documents that reflect the best available evidence and expert consensus supported in practice of CCT. This paper outlines SCCT's methodology for developing scientific documents. It was formulated by members of the SCCT Guidelines Committee and approved by the SCCT Board of Directors.

Clinical Applications of Photon-counting CT: A Review of Pioneer Studies and a Glimpse into the Future

CT systems equipped with photon-counting detectors (PCDs), referred to as photon-counting CT (PCCT), are beginning to change imaging in several subspecialties, such as cardiac, vascular, thoracic, and musculoskeletal radiology. Evidence has been building in the literature underpinning the many advantages of PCCT for different clinical applications. These benefits derive from the distinct features of PCDs, which are made of semiconductor materials capable of converting photons directly into electric signal. PCCT advancements include, among the most important, improved spatial resolution, noise reduction, and spectral properties. PCCT spatial resolution on the order of 0.25 mm allows for the improved visualization of small structures (eg, small vessels, arterial walls, distal bronchi, and bone trabeculations) and their pathologies, as well as the identification of previously undetectable anomalies. In addition, blooming artifacts from calcifications, stents, and other dense structures are reduced. The benefits of the spectral capabilities of PCCT are broad and include reducing radiation and contrast material dose for patients. In addition, multiple types of information can be extracted from a single data set (ie, multiparametric imaging), including quantitative data often regarded as surrogates of functional information (eg, lung perfusion). PCCT also allows for a novel type of CT imaging, K-edge imaging. This technique, combined with new contrast materials specifically designed for this modality, opens the door to new applications for imaging in the future.

The prevalence of osteopenia and osteoporosis after heart transplantation assessed using CT

OBJECTIVE

Osteoporosis is frequently observed in patients after heart transplantation (HT), although the prevalence long-term post-HT is unknown. Most studies investigating bone mineral density (BD) after HT were performed using dual-energy X-ray absorptiometry. In this study BD, including the prevalence of osteopenia and osteoporosis, was investigated using coronary computed tomography (CCT) long-term post-HT. Moreover, risk factors for abnormal BD were investigated.

METHODS

All first CCT scans between February 2018 and June 2020 used for the annual screening for cardiac allograft vasculopathy were included. Retransplantations and scans with not fully imaged vertebrae were excluded. BD was measured as a mean of the BD of three consecutive thoracic vertebrae and categorized into normal BD, osteopenia or osteoporosis. Binary logistic regression was used to find determinants for an abnormal BD. Linear regression was used to explore determinants for the mean Hounsfield unit (HU) value of the BD.

RESULTS

In total, 140 patients were included (median age 55.2 [42.9-64.9] years, 51 (36%) female). Time between HT and CT scan was 11.0 [7.3-16.1] years. In total, 80 (57%), 43 (31%), and 17 (12%) patients had a normal BD, osteopenia, or osteoporosis, respectively. Osteoporotic fracture or vertebrae fractures was seen in 11 (8%) patients. Determinants for an abnormal BD were recipient age (OR 1.10 (1.06-1.14), p<0.001) and prednisolone use (OR 3.75 (1.27-11.01), p=0.016). In linear regression, left ventricular assist device use pre-HT (p=0.024) and time since HT (p=0.046) were additional BD determinants.

DISCUSSION

Osteopenia and osteoporosis are frequently seen on CCT post-HT. More investigation on appropriate measures to maintain a normal BD in these patients are needed.

Trabecular bone density in middle-aged women with reproductive disorders

Besides age, estrogen exposure plays a crucial role in changes in bone density (BD) in women. Premature ovarian insufficiency (POI) and polycystic ovary syndrome (PCOS) are conditions in reproductive-aged women in which the exposure to estrogen is substantially different. Women with a history of preeclampsia (PE) are expected to have normal estrogen exposure. Within the CREw-IMAGO study, we investigated if trabecular BD is different in these women because of differences in the duration of estrogen exposure. Trabecular BD was measured in thoracic vertebrae on coronary CT scans. Women with an reduced estrogen exposure (POI) have a lower BD compared to women with an intermediate exposure (PE) (mean difference (MD) -26.8, 95% confidence interval (CI) -37.2 - -16.3). Women with a prolonged estrogen exposure (PCOS) have the highest BD (MD 15.0, 95% CI 4.3 - 25.7). These results support the hypothesis that the duration of estrogen exposure in these women is associated with trabecular BD.

Change in Androgenic Status and Cardiometabolic Profile of Middle-Aged Women with Polycystic Ovary Syndrome

Understanding the cardiovascular disease (CVD) risk for women with polycystic ovary syndrome (PCOS) at reproductive age is crucial. To investigate this, we compared the cardiometabolic profiles of different PCOS groups over a median interval of 15.8 years. The study focused on three groups: (1) women with PCOS who were hyperandrogenic at both initial and follow-up screening (HA-HA), (2) those who transitioned from hyperandrogenic to normoandrogenic (HA-NA), and (3) those who remained normoandrogenic (NA-NA). At initial and follow-up screenings, both HA-HA and HA-NA groups showed higher body mass indexes compared to the NA-NA group. Additionally, at follow-up, the HA-HA and HA-NA groups exhibited higher blood pressure, a higher prevalence of hypertension, elevated serum triglycerides and insulin levels, and lower levels of HDL cholesterol compared to the NA-NA group. Even after adjusting for BMI, significant differences persisted in HDL cholesterol levels and hypertension prevalence among the groups (HA-HA: 53.8%, HA-NA: 53.1%, NA-NA: 14.3%, p < 0.01). However, calcium scores and the prevalence of coronary plaques on CT scans were similar across all groups. In conclusion, women with PCOS and hyperandrogenism during their reproductive years exhibited an unfavorable cardiometabolic profile during their post-reproductive years, even if they changed to a normoandrogenic status.

Multimodality Imaging of Cardiac Paragangliomas

Paragangliomas are rare neuroendocrine tumors of extra-adrenal autonomic paraganglia origin. Paragangliomas rarely involve the heart, and they account for less than 1% of primary cardiac tumors. Most cardiac paragangliomas are incidentally detected at echocardiography or CT or during the workup of symptomatic patients with high catecholamine levels. Paragangliomas are typically located around the great vessels, coronary arteries (atrioventricular groove), or the atria, which can be explained by the tumor origin from the paraganglia and the distribution of the cardiac plexus. At MRI, cardiac paragangliomas typically have low to intermediate signal on T1-weighted images and high signal on T2-weighted images. The tumors are strongly vascularized, with high uptake on first-pass perfusion images and a heterogeneous pattern on late gadolinium enhancement images. Functional imaging is indicated for diagnostic confirmation and to screen for additional tumor locations or metastatic disease. Surgical excision is the only curative treatment. Cardiac CT angiography or invasive angiography should be performed preoperatively to precisely delineate tumor vascularization. In particular, its relation with the coronary arteries should be determined, as paragangliomas can be perfused by the coronary arteries, posing additional surgical challenges and the need for coronary revascularization. This imaging essay reviews the characteristics of paragangliomas and the use of multimodality imaging for diagnosis and treatment. Keywords: CT Angiography, Molecular Imaging, MR Imaging, PET/CT, Cardiac, Heart, Neoplasms-Primary © RSNA, 2023.

Radiation dose optimization for photon-counting CT coronary artery calcium scoring for different patient sizes: a dynamic phantom study

PURPOSE

To systematically assess the radiation dose reduction potential of coronary artery calcium (CAC) assessments with photon-counting computed tomography (PCCT) by changing the tube potential for different patient sizes with a dynamic phantom.

METHODS

A hollow artery, containing three calcifications of different densities, was translated at velocities corresponding to 0, < 60, 60-75, and > 75 beats per minute within an anthropomorphic phantom. Extension rings were used to simulate average- and large -sized patients. PCCT scans were made with the reference clinical protocol (tube potential of 120 kilovolt (kV)), and with 70, 90, Sn100, Sn140, and 140 kV at identical image quality levels. All acquisitions were reconstructed at a virtual monoenergetic energy level of 70 keV. For each calcification, Agatston scores and contrast-to-noise ratios (CNR) were determined, and compared to the reference with Wilcoxon signed-rank tests, with p < 0.05 indicating significant differences.

RESULTS

A decrease in radiation dose (22%) was achieved at Sn100 kV for the average-sized phantom. For the large phantom, Sn100 and Sn140 kV resulted in a decrease in radiation doses of 19% and 3%, respectively. Irrespective of CAC density, Sn100 and 140 kVp did not result in significantly different CNR. Only at Sn100 kV were there no significant differences in Agatston scores for all CAC densities, heart rates, and phantom sizes.

CONCLUSION

PCCT at tube voltage of 100 kV with added tin filtration and reconstructed at 70 keV enables a ≥ 19% dose reduction compared to 120 kV, independent of phantom size, CAC density, and heart rate.

KEY POINTS

• Photon-counting CT allows for reduced radiation dose acquisitions (up to 19%) for coronary calcium assessment by reducing tube voltage while reconstructing at a normal monoE level of 70 keV. • Tube voltage reduction is possible for medium and large patient sizes, without affecting the Agatston score outcome.

18F-FDG/PET-CT imaging findings after sternotomy

BACKGROUND

The clinical diagnosis of deep sternal wound infection (DSWI) is supported by imaging findings including 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT). To avoid misinterpretation due to normal post-surgery inflammation we assessed normal imaging findings in non-infected patients after sternotomy.

METHODS

This is a prospective cohort study including non-infectious patients with sternotomy. All patients underwent 18F-FDG-PET/CT at either 5 weeks (group 1), 12 weeks (group 2) or 52 weeks (group 3) post-surgery. 18F-FDG uptake was scored visually in five categories and assessed quantitatively.

RESULTS

A total of 44 patients were included. Sternal mean SUVmax was 7.34 (± 1.86), 5.22 (± 2.55) and 3.20 (± 1.80) in group 1, 2 and 3, respectively (p < 0.01). Sternal mean SUVmean was 3.84 (± 1.00), 2.69 (± 1.32) and 1.71 (± 0.98) in group 1, 2 and 3 (p < 0.01). All patients in group 1 had elevated uptake whereas group 2 and 3 showed 2/15 (13%) and 11/20 (55%) patients respectively with no elevated uptake. Group 3 still showed an elevated uptake pattern in in 9/20 (45%) and in 3/9 (33%) with a high-grade diffuse uptake pattern.

CONCLUSION

This study shows significant lower sternal 18F-FDG at 55 weeks compared to 5 weeks post-sternotomy however elevated uptake patterns may persist.

Added value of semi-quantitative analysis of [18F]FDG PET/CT for the diagnosis of device-related infections in patients with a left ventricular assist device

AIMS

Left ventricular assist devices (LVADs) improve quality of life and survival in patients with advanced heart failure, but device-related infections (DRIs) remain cumbersome. We evaluated the diagnostic capability of [18F]FDG PET/CT, factors affecting its accuracy, and the additive value of semi-quantitative analysis for the diagnosis of DRI.

METHODS AND RESULTS

LVAD recipients undergoing [18F]FDG PET/CT between 2012 and 2020 for suspected DRI were retrospectively included. [18F]FDG PET/CT was performed and evaluated in accordance with EANM guidelines. The final diagnosis of DRI, based on multidisciplinary consensus and findings during surgery, whenever performed, was used as the reference for diagnosis. 41 patients were evaluated for 59 episodes of suspected DRI. The clinical evaluation established driveline infection in 32 (55%) episodes, central device infection in 6 (11%), and combined infection in 2 (4%). Visual analysis of [18F]FDG PET/CT achieved a sensitivity and specificity for driveline infections of 0.79 and 0.71, respectively, whereas semi-quantitative analysis achieved a sensitivity and specificity of 0.94 and 0.83, respectively. For central device component infection, visual analysis of [18F]FDG PET/CT achieved a sensitivity and specificity of 0.75 and 0.60, respectively. Semi-quantitative analysis using SUVratio achieved a sensitivity and specificity of 1.0 and 0.8, respectively. The increase of specificity for central component infection was statistically significant (P = 0.05).

CONCLUSIONS

[18F]FDG PET/CT reliably predicts the presence of DRI in LVAD recipients. Semi-quantitative analysis may increase the specificity of [18F]FDG PET/CT for the analysis of central device component infection and should be considered in equivocal cases after visual analysis.

Photon-counting CT: Review of initial clinical results

Photon-counting computed tomography (PCCT) is a new technology that enables higher spatial resolution compared to conventional CT techniques, energy resolved imaging and spectral post-processing. This leads to improved contrast-to-noise ratio, artifact and potential dose reduction as well as elimination of electronic noise. Since the introduction of clinical PCCT in 2021, a shift has been observed from solely pre-clinical studies to clinical research (i.e. use of PCCT imaging in humans). This review article is focused on the initial clinical results of PCCT by explaining the current PCCT systems, the applications themselves and, the challenges of PCCT.

Photon-counting Detector CT in Patients Pre- and Post-Transcatheter Aortic Valve Replacement

Photon-counting detector CT (PCD CT) has increasingly garnered interest in cardiothoracic imaging due to its high spatial resolution and ability to perform spectral imaging. CT plays an important role in the planning and postprocedural assessment of transcatheter aortic valve replacement (TAVR). Limitations of current CT technology resulting in blooming and metal artifacts may be addressed with PCD CT. This case series demonstrates the potential advantages of PCD CT in patients prior to and post-TAVR. In TAVR planning, PCD CT allowed for a detailed depiction of the aortic valve, aortic root, coronary arteries, and potential vascular access routes. The high-spatial-resolution reconstructions enabled assessment of hypoattenuating leaflet thickening and periprosthetic leakage for prosthetic valves. This study shows promising initial results, but further research is needed to determine the clinical impact of PCD CT in patients prior to and post-TAVR. Keywords: Transcatheter Aortic Valve Replacement, Cardiac, Coronary Arteries, Heart, Valves, Photon-counting Detector CT © RSNA, 2023 An earlier incorrect version appeared online. This article was corrected on October 27, 2023.

Rationale and design of the iCORONARY trial: improving the cost-effectiveness of coronary artery disease diagnosis

BACKGROUND

In patients with stable coronary artery disease (CAD), revascularisation decisions are based mainly on the visual grading of the severity of coronary stenosis on invasive coronary angiography (ICA). However, invasive fractional flow reserve (FFR) is the current standard to determine the haemodynamic significance of coronary stenosis. Non-invasive and less-invasive imaging techniques such as computed-tomography-derived FFR (FFR-CT) and angiography-derived FFR (QFR) combine both anatomical and functional information in complex algorithms to calculate FFR.

TRIAL DESIGN

The iCORONARY trial is a prospective, multicentre, non-inferiority randomised controlled trial (RCT) with a blinded endpoint evaluation. It investigates the costs, effects and outcomes of different diagnostic strategies to evaluate the presence of CAD and the need for revascularisation in patients with stable angina pectoris who undergo coronary computed tomography angiography. Those with a Coronary Artery Disease-Reporting and Data System (CAD-RADS) score between 0-2 and 5 will be included in a prospective registry, whereas patients with CAD-RADS 3 or 4A will be enrolled in the RCT. The RCT consists of three randomised groups: (1) FFR-CT-guided strategy, (2) QFR-guided strategy or (3) standard of care including ICA and invasive pressure measurements for all intermediate stenoses. The primary endpoint will be the occurrence of major adverse cardiac events (death, myocardial infarction and repeat revascularisation) at 1 year.

CLINICALTRIALS

gov-identifier: NCT04939207.

CONCLUSION

The iCORONARY trial will assess whether a strategy of FFR-CT or QFR is non-inferior to invasive angiography to guide the need for revascularisation in patients with stable CAD. Non-inferiority to the standard of care implies that these techniques are attractive, less-invasive alternatives to current diagnostic pathways.

State-of-the-art CT and MR imaging and assessment of atherosclerotic carotid artery disease: the reporting-a consensus document by the European Society of Cardiovascular Radiology (ESCR)

The European Society of Cardiovascular Radiology (ESCR) is the European specialist society of cardiac and vascular imaging. This society's highest priority is the continuous improvement, development, and standardization of education, training, and best medical practice, based on experience and evidence. The present intra-society consensus is based on the existing scientific evidence and on the individual experience of the members of the ESCR writing group on carotid diseases, the members of the ESCR guidelines committee, and the members of the executive committee of the ESCR. The recommendations published herein reflect the evidence-based society opinion of ESCR. The purpose of this second document is to discuss suggestions for standardized reporting based on the accompanying consensus document part I. KEY POINTS: • CT and MR imaging-based evaluation of carotid artery disease provides essential information for risk stratification and prediction of stroke. • The information in the report must cover vessel morphology, description of stenosis, and plaque imaging features. • A structured approach to reporting ensures that all essential information is delivered in a standardized and consistent way to the referring clinician.

State-of-the-art CT and MR imaging and assessment of atherosclerotic carotid artery disease: standardization of scanning protocols and measurements-a consensus document by the European Society of Cardiovascular Radiology (ESCR)

The European Society of Cardiovascular Radiology (ESCR) is the European specialist society of cardiac and vascular imaging. This society's highest priority is the continuous improvement, development, and standardization of education, training, and best medical practice, based on experience and evidence. The present intra-society consensus is based on the existing scientific evidence and on the individual experience of the members of the ESCR writing group on carotid diseases, the members of the ESCR guidelines committee, and the members of the executive committee of the ESCR. The recommendations published herein reflect the evidence-based society opinion of ESCR. We have produced a twin-papers consensus, indicated through the documents as respectively "Part I" and "Part II." The first document (Part I) begins with a discussion of features, role, indications, and evidence for CT and MR imaging-based diagnosis of carotid artery disease for risk stratification and prediction of stroke (Section I). It then provides an extensive overview and insight into imaging-derived biomarkers and their potential use in risk stratification (Section II). Finally, detailed recommendations about optimized imaging technique and imaging strategies are summarized (Section III). The second part of this consensus paper (Part II) is focused on structured reporting of carotid imaging studies with CT/MR. KEY POINTS: • CT and MR imaging-based evaluation of carotid artery disease provides essential information for risk stratification and prediction of stroke. • Imaging-derived biomarkers and their potential use in risk stratification are evolving; their correct interpretation and use in clinical practice must be well-understood. • A correct imaging strategy and scan protocol will produce the best possible results for disease evaluation.

Wall shear stress-related plaque growth of lipid-rich plaques in human coronary arteries: an near-infrared spectroscopy and optical coherence tomography study

AIMS

Low wall shear stress (WSS) is acknowledged to play a role in plaque development through its influence on local endothelial function. Also, lipid-rich plaques (LRPs) are associated with endothelial dysfunction. However, little is known about the interplay between WSS and the presence of lipids with respect to plaque progression. Therefore, we aimed to study the differences in WSS-related plaque progression between LRPs, non-LRPs, or plaque-free regions in human coronary arteries.

METHODS AND RESULTS

In the present single-centre, prospective study, 40 patients who presented with an acute coronary syndrome successfully underwent near-infrared spectroscopy intravascular ultrasound (NIRS-IVUS) and optical coherence tomography (OCT) of at least one non-culprit vessel at baseline and completed a 1-year follow-up. WSS was computed applying computational fluid dynamics to a three-dimensional reconstruction of the coronary artery based on the fusion of the IVUS-segmented lumen with a CT-derived centreline, using invasive flow measurements as boundary conditions. For data analysis, each artery was divided into 1.5 mm/45° sectors. Plaque growth based on IVUS-derived percentage atheroma volume change was compared between LRPs, non-LRPs, and plaque-free wall segments, as assessed by both OCT and NIRS. Both NIRS- and OCT-detected lipid-rich sectors showed a significantly higher plaque progression than non-LRPs or plaque-free regions. Exposure to low WSS was associated with a higher plaque progression than exposure to mid or high WSS, even in the regions classified as a plaque-free wall. Furthermore, low WSS and the presence of lipids had a synergistic effect on plaque growth, resulting in the highest plaque progression in lipid-rich regions exposed to low shear stress.

CONCLUSION

This study demonstrates that NIRS- and OCT-detected lipid-rich regions exposed to low WSS are subject to enhanced plaque growth over a 1-year follow-up. The presence of lipids and low WSS proves to have a synergistic effect on plaque growth.

Aortic dilation and growth in women with Turner syndrome

OBJECTIVE

Women with Turner syndrome (TS) are at increased risk of aortic dissection, which is a life-threatening event associated with aortic dilation. Knowledge on the development of aortic dilation over time remains limited. This study aims to describe the prevalence of aortic dilation, to find associated factors and to study aortic growth in women with TS.

METHODS

In this prospective multicentre cohort study, consecutive adult women with genetically proven TS included between 2014 and 2016 underwent ECG-triggered multiphase CT angiography at baseline and after 3 years. Aortic diameters were measured at seven levels of the thoracic aorta using double oblique reconstruction and indexed for body surface area. Ascending aortic dilation was defined as an aortic size index >20 mm/m². Aorta-related and cardiovascular events were collected. Statistical analysis included linear and logistic regression and linear mixed effects models.

RESULTS

The cohort consisted of 89 women with a median age of 34 years (IQR: 24-44). Ascending aortic dilation was found in 38.2% at baseline. At baseline, age (OR: 1.08 (95% CI 1.03 to 1.13), p<0.001), presence of bicuspid aortic valve (BAV) (OR: 7.09 (95% CI 2.22 to 25.9), p=0.002) and systolic blood pressure (OR: 1.06 (95% CI 1.02 to 1.11), p=0.004) were independently associated with ascending aortic dilation. During a median follow-up of 3.0 (2.4-3.6) years (n=77), significant aortic growth was found only at the sinotubular junction (0.20±1.92 mm, p=0.021). No aortic dissection occurred, one patient underwent aortic surgery and one woman died.

CONCLUSIONS

In women with TS, ascending aortic dilation is common and associated with age, BAV and systolic blood pressure. Aortic diameters were stable during a 3-year follow-up, apart from a significant yet not clinically relevant increase at the sinotubular junction, which may suggest a more benign course of progression than previously reported.

Normal imaging findings after ascending aorta prosthesis implantation on 18F-Fluorodeoxyglucose Positron Emission Tomography with computed tomography

BACKGROUND

To diagnose abnormal 18F-Fluorodeoxyglucose (18F-FDG) uptake in suspected endocarditis after aortic root and/or ascending aorta prosthesis (ARAP) implantation, it is important to first establish the normal periprosthetic uptake on positron emission tomography with computed tomography (PET/CT).

METHODS

Patients with uncomplicated ARAP implantation were prospectively included and underwent 18F-FDG-PET/CT at either 12 (± 2) weeks (group 1) or 52 (± 8) weeks (group 2) after procedure. Uptake on three different locations of the prosthesis ("cranial anastomosis (CA)," "prosthetic heart valve (PHV)," "ascending aorta prosthesis (AAP)") was scored visually (none/low/intermediate/high) and quantitatively (maximum standardized uptake value (SUVmax) and target-to-background ratio (SUVratio).

RESULTS

In total, 20 patients (group 1: n = 10, group 2: n = 10) (mean age 64±7 years, 70% male) were included. Both groups had similar visual uptake intensity for all measured areas (CA: mostly low-intermediate (16/20 (80%)), p = .17; PHV: low-intermediate (16/20 (80%)), p = .88; AAP: low-intermediate (19/20 (95%)), p = .48). SUVmax for CA was 5.6 [4.1-6.1] and 3.8 [3.1-5.9] (median [IQR], p = .19), and around PHV 5.0 [4.1-5.7] and 6.3 [4.6-7.1] (p = .11) for groups 1 and 2, respectively. SUVratio for CA was 2.8 [2.3-3.2] and 2.0 [1.7-2.6] (median [IQR], p = .07) and around PHV 2.5 [2.4-2.8] and 2.9 [2.3-3.5] (median [IQR], p = .26) for groups 1 and 2, respectively.

CONCLUSION

No significant differences were observed between PET/CT findings at 3 months and 1 year after ARAP implantation, warranting caution in interpretation of PET/CT in the first year after implantation.

Relapsing low-flow alarms due to suboptimal alignment of the left ventricular assist device inflow cannula

OBJECTIVES

This retrospective study investigated the correlation between the angular position of the left ventricular assist device (LVAD) inflow cannula and relapsing low-flow alarms.

METHODS

Medical charts were reviewed of all patients with HeartMate 3 LVAD support for relapsing low-flow alarms. A standardized protocol was created to measure the angular position with a contrast-enhanced computed tomography scan. Statistics were done using a gamma frailty model with a constant rate function.

RESULTS

For this analysis, 48 LVAD-supported patients were included. The majority of the patients were male (79%) with a median age of 57 years and a median follow-up of 30 months (interquartile range: 19-41). Low-flow alarm(s) were experienced in 30 (63%) patients. Angulation towards the septal-lateral plane showed a significant increase in low-flow alarms over time with a constant rate function of 0.031 increase in low-flow alarms per month of follow-up per increasing degree of angulation (P = 0.048). When dividing this group using an optimal cut-off point, a significant increase in low-flow alarms was observed when the septal-lateral angulation was 28° or more (P = 0.001). Anterior-posterior and maximal inflow cannula angulation did not show a significant difference.

CONCLUSIONS

This study showed an increasing number of low-flow alarms when the degrees of LVAD inflow cannula expand towards the septal-lateral plane. This emphasizes the importance of the LVAD inflow cannula angular position to prevent relapsing low-flow alarms with the risk of diminished quality of life and morbidity.

Incidental findings on coronary computed tomography in women with selected reproductive disorders

OBJECTIVE

To determine the prevalence of incidental findings (IFs) on coronary computed tomography (CCT) in women aged 45-55 years and previously diagnosed with reproductive disorders such as polycystic ovary syndrome (PCOS), premature ovarian insufficiency (POI) or preeclampsia (PE).

METHODS

A total of 486 middle-aged women with PCOS (n = 101), POI (n = 97) or a history of PE (n = 288) underwent a CCT as part of a prior prospective study. IFs were categorized by their significance (minor, moderate and major). Follow-up information was collected from patients' records. To investigate the impact of different field of views (FOVs), a subset of scans was analyzed in full FOV and small FOV.

RESULTS

In 96/486 (19.8%) women, one or more IFs were detected, of which 54/486 (11.1%) were classified as moderate/major and 48/486 (9.9%) required follow-up. A moderate/major IF was detected in 16/101 (15.9%) women with PCOS, 13/97 (13.4%) women with POI and 25/288 (8.7%) women with a history of PE. In 78 women with an IF detected in the full FOV, the IF was still visible in 60 (76.9%) women in the small FOV. In the full FOV, 46 women required follow-up, but using the small FOV this was reduced to 30 women.

CONCLUSION

Using CCT as a cardiovascular disease screening tool in women with selected reproductive disorders increases the probability of detecting IFs that can cause anxiety and may generate extra costs, but can also reveal clinically relevant findings. Using a small FOV centered around the heart resulted in a lower prevalence of IFs and required less follow-up.

Longitudinal changes of thoracic aortic diameters in the general population aged 55 years or older

OBJECTIVE

Longitudinal data on age-related changes in the diameters of the thoracic aorta are scarce. To better understand normal variation and to identify factors influencing this process, we aimed to report male-female-specific and age-specific aortic growth rate in the ageing general population and identify factors associated with growth rate.

METHODS

From the prospective population-based Rotterdam Study, 943 participants (52.0% females, median age at baseline 65 years (62-68)) underwent serial non-enhanced cardiac CT. We measured the diameters of the ascending (AA) and descending aorta (DA) at two time points and expressed absolute and relative differences. Linear mixed effects analysis was performed to identify determinants associated with change in aortic diameters.

RESULTS

Mean AA diameter at baseline was 37.3±3.6 mm in male population and 34.7±3.2 mm in female population, mean DA diameter was 29.6±2.3 in male population and 26.9±2.2 mm in female population. The median absolute change in diameters during follow-up (mean scan interval 14.1±0.3 years) was 1 mm (0-2) for both the AA and DA. Absolute change per decade in AA diameter was significantly larger in males than in females (0.72 mm/decade (0.00-1.43) vs 0.70 mm/decade (0.00-1.41), p=0.006), as well as absolute change in AD diameter (0.71 mm/decade (0.00-1.42) vs 0.69 mm/decade (0.00-1.36), p=0.008). There was no significant difference between male and female population in relative change of their aortic diameters during follow-up. Age, male sex, higher body mass index (BMI) and higher diastolic blood pressure (DBP) showed a statistically significant independent association with increase in AA and DA diameters over time.

CONCLUSIONS

Some degree of increase in thoracic aortic diameters is typical in both men and women of an aging population. Factors associated with this change in thoracic aortic diameters were sex, age, BMI and DBP.

Thoracic Aortic Diameter and Cardiovascular Events and Mortality among Women and Men

Background Thoracic aortic diameter may have a role as a biomarker for major adverse cardiovascular events. Purpose To evaluate the sex-specific association of the diameters of the ascending (AA) and descending (DA) thoracic aorta with risk of stroke, coronary heart disease, heart failure, cardiovascular mortality, and all-cause mortality. Materials and Methods Study participants from the population-based Rotterdam Study who underwent multidetector-row CT between 2003 and 2006 were evaluated. Cox proportional hazard models were conducted to evaluate the associations of AA and DA diameters indexed and not indexed for body mass index (BMI) with cardiovascular events and mortality for men and women. Hazard ratios (HRs) were calculated per 1-unit greater SD of aortic diameters. Results A total of 2178 participants (mean age, 69 years; 55% women) were included. Mean follow-up was 9 years. Each 0.23-mm/(kg/m²) larger BMI-indexed AA diameter was associated with a 33% higher cardiovascular mortality risk in women (HR, 1.33; 95% CI: 1.03, 1.73). Each 0.16-mm/(kg/m²) larger BMI-indexed DA diameter was associated with a 38% higher risk of stroke (HR, 1.38; 95% CI: 1.07, 1.78) and with a 46% greater risk of cardiovascular mortality (HR, 1.46; 95% CI: 1.10, 1.94) in women. Larger BMI-indexed AA and DA diameters were associated with greater risk of all-cause mortality in both sexes. Conclusion Larger ascending and descending thoracic aortic diameters indexed by body mass index were associated with greater risk of adverse cardiovascular outcomes and mortality in women and men. Clinical trial registration no. NTR6831 © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by Williams in this issue.

Coronary calcium scores on dual-source photon-counting computed tomography: an adapted Agatston methodology aimed at radiation dose reduction

Objectives

The aim of this study was to determine mono-energetic (monoE) level–specific photon-counting CT (PCCT) Agatston thresholds, to yield monoE level independent Agatston scores validated with a dynamic cardiac phantom. Also, we examined the potential of dose reduction for PCCT coronary artery calcium (CAC) studies, when reconstructed at low monoE levels.

Methods

Theoretical CAC monoE thresholds were calculated with data from the National Institute of Standards and Technology (NIST) database. Artificial CAC with three densities were moved in an anthropomorphic thorax phantom at 0 and 60–75 bpm, and scanned at full and 50% dose on a first-generation dual-source PCCT. For all densities, Agatston scores and maximum CT numbers were determined. Agatston scores were compared with the reference at full dose and 70 keV monoE level; deviations (95% confidence interval) < 10% were deemed to be clinically not-relevant.

Results

Averaged over all monoE levels, measured CT numbers deviated from theoretical CT numbers by 6%, 13%, and − 4% for low-, medium-, and high-density CAC, respectively. At 50% reduced dose and 60–75 bpm, Agatston score deviations were non-relevant for 60 to 100 keV and 60 to 120 keV for medium- and high-density CAC, respectively.

Conclusion

MonoE level–specific Agatston score thresholds resulted in similar scores as in standard reconstructions at 70 keV. PCCT allows for a potential dose reduction of 50% for CAC scoring using low monoE reconstructions for medium- and high-density CAC.

Key Points

• Mono-energy level–specific Agatston thresholds allow for reproducible coronary artery calcium quantification on mono-energetic images.

• Increased calcium contrast-to-noise ratio at reduced mono-energy levels allows for coronary artery calcium quantification at 50% reduced radiation dose for medium- and high-density calcifications.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00330-022-08642-5.

Reproducibility of coronary artery calcium quantification on dual-source CT and dual-source photon-counting CT: a dynamic phantom study

To systematically compare coronary artery calcium (CAC) quantification between conventional computed tomography (CT) and photon-counting CT (PCCT) at different virtual monoenergetic (monoE) levels for different heart rates. A dynamic (heart rates of 0, < 60, 60-75, and > 75 bpm) anthropomorphic phantom with three calcification densities was scanned using routine clinical CAC protocols with CT and PCCT. In addition to the standard clinical protocol of 70 keV, PCCT images were reconstructed at monoE levels of 72, 74, and 76 keV. CAC was quantified using Agatston, volume, and mass scores. Agatston scores 95% confidence intervals (CI) were calculated and compared between PCCT and CT. Volume and mass scores were compared with physical quantities. For all CAC densities, routine clinical protocol Agatston scores of static CAC were higher for PCCT compared to CT. At < 60 bpm, Agatston scores at 74 and 76 keV reconstructions were reproducible (overlapping CI) for PCCT and CT. Increased heart rates yielded different Agatston scores for PCCT in comparison with CT, for all monoE levels. Low density CAC volume scores showed the largest deviation from physical volume, with mean deviations of 59% and 77% for CT and PCCT, respectively. Overall, mass scores underestimated physical mass by 10%, 38%, and 59% for low, medium, and high density CAC, respectively. PCCT allows for reproducible Agatston scores for dynamic CAC (< 60 bpm) when reconstructed at monoE levels of 74 or 76 keV, regardless of CAC density. Deviations from physical volume and mass were, in general, large for both CT and PCCT.

Wall shear stress angle is associated with aortic growth in bicuspid aortic valve patients

AIMS

Aortic wall shear stress (WSS) distributions in bicuspid aortic valve (BAV) patients have been associated with aortic dilatation, but prospective, longitudinal data are missing. This study assessed differences in aortic WSS distributions between BAV patients and healthy controls and determined the association of WSS with aortic growth in patients.

METHODS AND RESULTS

Sixty subjects underwent four-dimensional (4D) flow cardiovascular magnetic resonance of the thoracic aorta (32 BAV patients and 28 healthy controls). Peak velocity, pulse wave velocity, aortic distensibility, peak systolic WSS (magnitude, axial, and circumferential), and WSS angle were assessed. WSS angle is defined as the angle between the WSSmagnitude and WSSaxial component. In BAV patients, three-year computed tomography angiography-based aortic volumetric growth was determined in the proximal and entire ascending aorta. WSSaxial was significantly lower in BAV patients compared with controls (0.93 vs. 0.72 Pa, P = 0.047) and WSScircumferential and WSS angle were significantly higher (0.29 vs. 0.64 Pa and 18° vs. 40°, both P < 0.001). Significant volumetric growth of the proximal ascending aorta occurred in BAV patients (from 49.1 to 52.5 cm3, P = 0.003). In multivariable analysis corrected for baseline aortic volume and diastolic blood pressure, WSS angle was the only parameter independently associated with proximal aortic growth (P = 0.031). In the entire ascending aorta, besides the WSS angle, the WSSmagnitude was also independently associated with growth.

CONCLUSION

Increased WSScircumferential and especially WSS angle are typical in BAV patients. WSS angle was found to predict aortic growth. These findings highlight the potential role of WSS measurements in BAV patients to stratify patients at risk for aortic dilation.

Distribution of Aortic Root Calcium in Relation to Frame Expansion and Paravalvular Leakage After Transcatheter Aortic Valve Implantation (TAVI): An Observational Study Using a Patient-specific Contrast Attenuation Coefficient for Calcium Definition and Independent Core Lab Analysis of Paravalvular Leakage

BACKGROUND

Calcium is a determinant of paravalvular leakage (PVL) after transcatheter aortic valve implantation (TAVI). This is based on a fixed contrast attenuation value while X-ray attenuation is patient-dependent and without considering frame expansion and PVL location. We examined the role of calcium in (site-specific) PVL after TAVI using a patient-specific contrast attenuation coefficient combined with frame expansion.

METHODS

57 patients were included with baseline CT, post-TAVI transthoracic echocardiography and rotational angiography (R-angio). Calcium load was assessed using a patient-specific contrast attenuation coefficient. Baseline CT and post-TAVI R-angio were fused to assess frame expansion. PVL was assessed by a core lab.

RESULTS

Overall, the highest calcium load was at the non-coronary-cusp-region (NCR, 436 mm³) vs. the right-coronary-cusp-region (RCR, 233 mm³) and the left-coronary-cusp-region (LCR, 244 mm³), p < 0.001. Calcium load was higher in patients with vs. without PVL (1,137 vs. 742 mm³, p = 0.012) and was an independent predictor of PVL (odds ratio, 4.83, p = 0.004). PVL was seen most often in the LCR (39% vs. 21% [RCR] and 19% [NCR]). The degree of frame expansion was 71% at the NCR, 70% at the RCR and 74% at the LCR without difference between patients with or without PVL.

CONCLUSIONS

Calcium load was higher in patients with PVL and was an independent predictor of PVL. While calcium was predominantly seen at the NCR, PVL was most often at the LCR. These findings indicate that in addition to calcium, specific anatomic features play a role in PVL after TAVI.

Best Practices for Imaging Cardiac Device-Related Infections and Endocarditis: A JACC: Cardiovascular Imaging Expert Panel Statement

The diagnosis of cardiac device infection and, more importantly, accurate localization of the infection site, such as defibrillator pocket, pacemaker lead, along the peripheral driveline or central portion of the left ventricular assist device, prosthetic valve ring abscesses, and perivalvular extensions, remain clinically challenging. Although transthoracic and transesophageal echocardiography are the first-line imaging tests in suspected endocarditis and for assessing hemodynamic complications, recent studies suggest that cardiac computed tomography (CT) or CT angiography and functional imaging with ¹⁸F-fluoro-2-deoxyglucose (FDG) positron emission tomography (PET) with CT (FDG PET/CT) may have an incremental role in technically limited or inconclusive cases on echocardiography. One of the key benefits of FDG PET/CT is in its detection of inflammatory cells early in the infection process, before morphological damages ensue. However, there are many unanswered questions in the literature. In this document, we provide consensus on best practices among the various imaging studies, which includes the detection of cardiac device infection, differentiation of infection from inflammation, image-guided patient management, and detailed recommendations on patient preparation, image acquisition, processing, interpretation, and standardized reporting.

Transcatheter Aortic Valve Implantation: The Evolving Role of the Radiologist in 2021

BACKGROUND

 Transcatheter aortic valve implantation (TAVI) has gained worldwide acceptance and implementation as an alternative therapeutic option in patients with severe aortic valve stenosis unable to safely undergo surgical aortic valve replacement. This transformative technique places the radiologist in a key position in the pre-procedural assessment of potential candidates for this technique, delivering key anatomical information necessary for patient eligibility and procedural safety. Recent trials also provide encouraging results to potentially extend the indication to patients with safer risk profiles.

METHOD

 The review is based on a PubMed literature search using the search terms "transcatheter heart valve", "TAVI", "TAVR", "CT", "imaging", "MR" over a period from 2010-2020, combined with personal comments based on the author's experience.

RESULTS AND CONCLUSION

 CT plays a prominent role in the pre-procedural workup, delivering as a true 3D imaging modality optimal visualization of the complex anatomy of the aortic root with simultaneous evaluation of the patency of the different access routes. As such, the contribution of CT is key for the determination of patient eligibility and procedural safety. This input is supplementary to the contributions of other imaging modalities and forms an important element in the discussions of the Heart Valve Team. Knowledge of the procedure and its characteristics is necessary in order to provide a comprehensive and complete report. While the role of CT in the pre-procedural evaluation is well established, the contribution of CT and MR and the clinical significance of their findings in the routine follow-up after the intervention are less clear and currently the subject of intense investigation. Important issues remain, including the occurrence and significance of subclinical leaflet thrombosis, prosthetic heart valve endocarditis, and long-term structural valve degeneration.

KEY POINTS

  · CT plays a crucial role in evaluating transcatheter heart valve candidates. · Evaluation must include the dimensions of the aortic root and access paths. · The exact post-procedural role of CT and MRI has not yet been determined..

CITATION FORMAT

· Salgado R, El Addouli H, Budde RP. Transcatheter Aortic Valve Implantation: The Evolving Role of the Radiologist in 2021. Fortschr Röntgenstr 2021; 193: 1411 - 1425.

Novel Morphological Features on CMR for the Prediction of Pathogenic Sarcomere Gene Variants in Subjects Without Hypertrophic Cardiomyopathy

Background: Carriers of pathogenic DNA variants (G+) causing hypertrophic cardiomyopathy (HCM) can be identified by genetic testing. Several abnormalities have been brought forth as pre-clinical expressions of HCM, some of which can be identified by cardiovascular magnetic resonance (CMR). In this study, we assessed morphological differences between G+/left ventricular hypertrophy-negative (LVH-) subjects and healthy controls and examined whether CMR-derived variables are useful for the prediction of sarcomere gene variants.

Methods: We studied 57 G+ subjects with a maximal wall thickness (MWT) < 13 mm, and compared them to 40 healthy controls matched for age and sex on a group level. Subjects underwent CMR including morphological, volumetric and function assessment. Logistic regression analysis was performed for the determination of predictive CMR characteristics, by which a scoring system for G+ status was constructed.

Results: G+/LVH- subjects were subject to alterations in the myocardial architecture, resulting in a thinner posterior wall thickness (PWT), higher interventricular septal wall/PWT ratio and MWT/PWT ratio. Prominent hook-shaped configurations of the anterobasal segment were only observed in this group. A model consisting of the anterobasal hook, multiple myocardial crypts, right ventricular/left ventricular ratio, MWT/PWT ratio, and MWT/left ventricular mass ratio predicted G+ status with an area under the curve of 0.92 [0.87–0.97]. A score of ≥3 was present only in G+ subjects, identifying 56% of the G+/LVH- population.

Conclusion: A score system incorporating CMR-derived variables correctly identified 56% of G+ subjects. Our results provide further insights into the wide phenotypic spectrum of G+/LVH- subjects and demonstrate the utility of several novel morphological features. If genetic testing for some reason cannot be performed, CMR and our purposed score system can be used to detect possible G+ carriers and to aid planning of the control intervals.

Normal imaging findings after aortic valve implantation on 18F-Fluorodeoxyglucose positron emission tomography with computed tomography

BACKGROUND

To determine the normal perivalvular 18F-Fluorodeoxyglucose (18F-FDG) uptake on positron emission tomography (PET) with computed tomography (CT) within one year after aortic prosthetic heart valve (PHV) implantation.

METHODS

Patients with uncomplicated aortic PHV implantation were prospectively included and underwent 18F-FDG PET/CT at either 5 (± 1) weeks (group 1), 12 (± 2) weeks (group 2) or 52 (± 8) weeks (group 3) after implantation. 18F-FDG uptake around the PHV was scored qualitatively (none/low/intermediate/high) and quantitatively by measuring the maximum Standardized Uptake Value (SUVmax) and target to background ratio (SUVratio).

RESULTS

In total, 37 patients (group 1: n = 12, group 2: n = 12, group 3: n = 13) (mean age 66 ± 8 years) were prospectively included. Perivalvular 18F-FDG uptake was low (8/12 (67%)) and intermediate (4/12 (33%)) in group 1, low (7/12 (58%)) and intermediate (5/12 (42%)) in group 2, and low (8/13 (62%)) and intermediate (5/13 (38%)) in group 3 (P = 0.91). SUVmax was 4.1 ± 0.7, 4.6 ± 0.9 and 3.8 ± 0.7 (mean ± SD, P = 0.08), and SUVratio was 2.0 [1.9 to 2.2], 2.0 [1.8 to 2.6], and 1.9 [1.7 to 2.0] (median [IQR], P = 0.81) for groups 1, 2, and 3, respectively.

CONCLUSION

Non-infected aortic PHV have similar low to intermediate perivalvular 18F-FDG uptake with similar SUVmax and SUVratio at 5, 12, and 52 weeks after implantation.

Added value of 18F-FDG-PET/CT and cardiac CTA in suspected transcatheter aortic valve endocarditis

BACKGROUNDS

Transcatheter-implanted aortic valve infective endocarditis (TAVI-IE) is difficult to diagnose when relying on the Duke Criteria. Our aim was to assess the additional diagnostic value of 18F-fluorodeoxyglucose (18F-FDG) positron emission/computed tomography (PET/CT) and cardiac computed tomography angiography (CTA) in suspected TAVI-IE.

METHODS

A multicenter retrospective analysis was performed in all patients who underwent 18F-FDG-PET/CT and/or CTA with suspected TAVI-IE. Patients were first classified with Duke Criteria and after adding 18F-FDG-PET/CT and CTA, they were classified with European Society of Cardiology (ESC) criteria. The final diagnosis was determined by our Endocarditis Team based on ESC guideline recommendations.

RESULTS

Thirty patients with suspected TAVI-IE were included. 18F-FDG-PET/CT was performed in all patients and Cardiac CTA in 14/30. Using the Modified Duke Criteria, patients were classified as 3% rejected (1/30), 73% possible (22/30), and 23% definite (7/30) TAVI-IE. Adding 18F-FDG-PET/CT and CTA supported the reclassification of 10 of the 22 possible cases as "definite TAVI-IE" (5/22) or "rejected TAVI-IE" (5/22). This changed the final diagnosis to 20% rejected (6/30), 40% possible (12/30), and 40% definite (12/30) TAVI-IE.

CONCLUSIONS

Addition of 18F-FDG-PET/CT and/or CTA changed the final diagnosis in 33% of patients and proved to be a valuable diagnostic tool in patients with suspected TAVI-IE.

A case report of an interrupted inferior vena cava and azygos continuation: implications for preoperative screening in minimally invasive cardiac surgery

Background

Femoral cannulation is commonly used in minimally invasive cardiac surgery to establish extracorporeal circulation. We present a case with a finding that should be evaluated when screening candidates for minimally invasive cardiac surgery.

Case summary

A 57-year-old male patient was scheduled for minimally invasive repair of the mitral and tricuspid valve and a MAZE procedure. During surgery there was difficulty advancing the venous cannula inserted in the right femoral vein. On transoesophageal echocardiography a guidewire advanced from the femoral vein was observed entering the right atrium from the superior vena cava. Despite inserting a second venous cannula in the jugular vein, venous drainage was insufficient for minimal invasive surgery. The approach was converted to a median sternotomy with bicaval cannulation. Re-examination of the preoperative computed tomography (CT) scan showed an interrupted inferior vena cava (IVC) with azygos continuation.

Discussion

In patients with major venous malformations such as the interrupted IVC with azygos continuation a full sternotomy is the preferred approach. The venous system should be evaluated when screening candidates for minimally invasive mitral valve surgery with preoperative CT. Additional cues to suspect interruption of the IVC are polysplenia and a broad superior mediastinal projection on the chest radiograph, mimicking a right paratracheal mass.

Dynamic Myocardial Perfusion CT for the Detection of Hemodynamically Significant Coronary Artery Disease

OBJECTIVES

In this international, multicenter study, using third-generation dual-source computed tomography (CT), we investigated the diagnostic performance of dynamic stress CT myocardial perfusion imaging (CT-MPI) in addition to coronary CT angiography (CTA) compared to invasive coronary angiography (ICA) and invasive fractional flow reserve (FFR).

BACKGROUND

CT-MPI combined with coronary CTA integrates coronary artery anatomy with inducible myocardial ischemia, showing promising results for the diagnosis of hemodynamically significant coronary artery disease in single-center studies.

METHODS

At 9 centers in Europe, Japan, and the United States, 132 patients scheduled for ICA were enrolled; 114 patients successfully completed coronary CTA, adenosine-stress dynamic CT-MPI, and ICA. Invasive FFR was performed in vessels with 25% to 90% stenosis. Data were analyzed by independent core laboratories. For the primary analysis, for each coronary artery the presence of hemodynamically significant obstruction was interpreted by coronary CTA with CT-MPI compared to coronary CTA alone, using an FFR of ≤0.80 and angiographic severity as reference. Territorial absolute myocardial blood flow (MBF) and relative MBF were compared using C-statistics.

RESULTS

ICA and FFR identified hemodynamically significant stenoses in 74 of 289 coronary vessels (26%). Coronary CTA with ≥50% stenosis demonstrated a per-vessel sensitivity, specificity, and accuracy for the detection of hemodynamically significant stenosis of 96% (95% CI: 91–100), 72% (95% CI: 66–78), and 78% (95% CI: 73–83), respectively. Coronary CTA with CT-MPI showed a lower sensitivity (84%; 95% CI: 75–92) but higher specificity (89%; 95% CI: 85–93) and accuracy (88%; 95% CI: 84–92). The areas under the receiver-operating characteristic curve of absolute MBF and relative MBF were 0.79 (95% CI: 0.71–0.86) and 0.82 (95% CI: 0.74–0.88), respectively. The median dose-length product of CT-MPI and coronary CTA were 313 mGy·cm and 138 mGy·cm, respectively.

CONCLUSIONS

Dynamic CT-MPI offers incremental diagnostic value over coronary CTA alone for the identification of hemodynamically significant coronary artery disease. Generalized results from this multicenter study encourage broader consideration of dynamic CT-MPI in clinical practice. (Dynamic Stress Perfusion CT for Detection of Inducible Myocardial Ischemia [SPECIFIC]; NCT02810795)

18F-FDG-Uptake in Mediastinal Lymph Nodes in Suspected Prosthetic Valve Endocarditis: Predictor or Confounder?

Introduction: Prosthetic valve endocarditis (PVE) is a serious disease affecting ~0.4% of prosthetic valve recipients per year. ¹⁸F-FDG-PET/CT has high sensitivity and specificity for PVE and is included as major criterion for the diagnosis in recent guidelines of the European Society of Cardiology. We addressed the question whether increased FDG-uptake in mediastinal lymph nodes could help to support the visual diagnostic assessment of PVE. Methods: In this sub-analysis of a previously published retrospective multicentre study, 160 unique patients were identified who underwent ¹⁸F-FDG-PET/CT for evaluation of suspected PVE. ¹⁸F-FDG-PET/CT was performed in adherence to the European Association of Nuclear Medicine guidelines of 2015 and scans were assessed for signs of mediastinal lymph node activity by 2 experienced nuclear medicine physicians who were blinded to clinical context. Clinical diagnosis of PVE had been established based on surgical findings or multidisciplinary consensus after a 1-year follow-up in 80 of 160 patients (50%). Results: In total, 52 patients showed increased mediastinal lymph node activity. Mediastinal lymph node activity on ¹⁸F-FDG-PET/CT did not increase diagnostic accuracy when added to the visual analysis of scans for signs of PVE: X ²: 0.118, p = 0.731). After excluding patients with known confounders for ¹⁸F-FDG-PET/CT, namely use of Bioglue® during prosthetic valve implantation and C-reactive protein levels below 40 mg/L, mediastinal lymph node activity was still not of additional diagnostic value compared to visual analysis alone (X²:0.129, p = 0.723). Discussion: Assessment of mediastinal lymph node activity did not improve ¹⁸F-FDG-PET/CT diagnostic accuracy for suspected PVE compared to visual assessment of the valve alone, as it seems to be a rather a specific finding, that might be caused by sternal wound or mediastinal infections or even by subclinical respiratory infections. Future studies might elucidate whether increased FDG active lymph nodes indicate a high-risk patient group and whether more detailed assessment of mediastinal lymph nodes could improve their additional diagnostic benefit.

18F-FDG PET/CT in Infective Endocarditis: Indications and Approaches for Standardization

Purpose of Review

Additional imaging modalities, such as FDG-PET/CT, have been included into the workup for patients with suspected infective endocarditis, according to major international guidelines published in 2015. The purpose of this review is to give an overview of FDG-PET/CT indications and standardized approaches in the setting of suspected infective endocarditis.

Recent Findings

There are two main indications for performing FDG-PET/CT in patients with suspected infective endocarditis: (i) detecting intracardiac infections and (ii) detection of (clinically silent) disseminated infectious disease. The diagnostic performance of FDG-PET/CT for intracardiac lesions depends on the presence of native valves, prosthetic valves, or implanted cardiac devices, with a sensitivity that is poor for native valve endocarditis and cardiac device-related lead infections, but much better for prosthetic valve endocarditis and cardiac device-related pocket infections. Specificity is high for all these indications. The detection of disseminated disease may also help establish the diagnosis and/or impact patient management.

Summary

Based on current evidence, FDG-PET/CT should be considered for detection of disseminated disease in suspected endocarditis. Absence of intracardiac lesions on FDG-PET/CT cannot rule out native valve endocarditis, but positive findings strongly support the diagnosis. For prosthetic valve endocarditis, standard use of FDG-PET/CT is recommended because of its high sensitivity and specificity. For implanted cardiac devices, FDG-PET/CT is also recommended, but should be evaluated with careful attention to clinical context, because its sensitivity is high for pocket infections, but low for lead infections. In patients with prosthetic valves with or without additional aortic prosthesis, combination with CTA should be considered. Optimal timing of FDG-PET/CT is important, both during clinical workup and technically (i.e., post tracer injection). In addition, procedural standardization is key and encompasses patient preparation, scan acquisition, reconstruction, subsequent analysis, and clinical interpretation. The recommendations discussed here will hopefully contribute to improved standardization and enhanced performance of FDG-PET/CT in the clinical management of patients with suspected infective endocarditis.