Evaluation of ECG-Gated, High-Pitch Thoracoabdominal Angiographies With Dual-Source Photon-Counting Detector Computed Tomography

PURPOSE

The aim of this study was to evaluate the radiation dose, image quality, and the potential of virtual monoenergetic imaging (VMI) reconstructions of high-pitch computed tomography angiography (CTA) of the thoracoabdominal aorta on a dual-source photon-counting detector-CT (PCD-CT) in comparison with an energy-integrating detector-CT (EID-CT), with a special focus on low-contrast attenuation.

METHODS

Consecutive patients being referred for an electrocardiogram (ECG)-gated, high-pitch CTA of the thoracoabdominal aorta prior to transcatheter aortic valve replacement (TAVR), and examined on the PCD-CT, were included in this prospective single-center study. For comparison, a retrospective patient group with ECG-gated, high-pitch CTA examinations of the thoracoabdominal aorta on EID-CT with a comparable scan protocol was matched for gender, body mass index, height, and age. Virtual monoenergetic imaging reconstructions from 40 to 120 keV were performed. Enhancement and noise were measured in 7 vascular segments and the surrounding air as mean and standard deviation of CT values. The radiation dose was noted and signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. Finally, a subgroup analysis was performed, comparing VMI reconstructions from 40 keV to 70 keV in patients with at least a 50% decrease in contrast attenuation between the ascending aorta and femoral arteries.

RESULTS

Fifty patients (mean age 77.0±14.5 years; 31 women) were included. The radiation dose was significantly lower on the PCD-CT (4.2±1.4 vs. 7.2±2.2 mGy; p<0.001). With increasing keV, vascular noise, SNR, and CNR decreased. Intravascular attenuation was significantly higher on VMI at levels from 40 to 65, compared with levels of 120 keV (p<0.01 and p<0.005, respectively). On the PCD-CT, SNR was significantly higher in keV levels 40 and 70 (all p<0.001), and CNR was higher at keV levels 40 and 45 (each p<0.001), compared with scans on the EID-CT. At VMI ≤60 keV, image noise was also significantly higher than that in the control group. The subgroup analysis showed a drastically improved diagnostic performance of the low-keV images in patients with low-contrast attenuation.

CONCLUSION

The ECG-gated CTA of the thoracoabdominal aorta in high-pitch mode on PCD-CT have significantly lower radiation dose and higher objective image quality than EID-CT. In addition, low-keV VMI can salvage suboptimal contrast studies, further reducing radiation dose by eliminating the need for repeat scans.

CLINICAL IMPACT

ECG-gated CT-angiographies of the thoracoabdominal aorta can be acquired with a lower radtiation dose and a better image quality by using a dual-source photon-countinge detector CT. Furthermore, the inherent spectral data offers the possiblity to improve undiagnostic images and thus saves the patient from further radiation and contrast application.

Improved Thermal Sensitivity Using Virtual Monochromatic Imaging Derived from Photon Counting Detector CT Data Sets: Ex Vivo Results of CT-Guided Cryoablation in Porcine Liver

PURPOSE

To investigate differences in thermal sensitivity of virtual monoenergetic imaging (VMI) series generated from photon-counting detector (PCD) CT data sets, regarding their use to improve discrimination of the ablation zone during percutaneous cryoablation.

MATERIALS AND METHODS

CT-guided cryoablation was performed using an ex vivo model of porcine liver on a PCD-CT system. The ablation zone was imaged continuously for 8 min by acquiring a CT scan every 5 s. Tissue temperature was measured using fiberoptic temperature probes placed parallel to the cryoprobe. CT-values and noise were measured at the tip of the temperature probes on each scan and on VMI series from 40 to 130 keV. Correlation of CT-values and temperature was assessed using linear regression analyses.

RESULTS

For the whole temperature range of [- 40, + 20] °C, we observed a linear correlation between CT-values and temperature in reference 70 keV images (R2 = 0.60, p < 0.001) with a thermal sensitivity of 1.4HU/°C. For the most dynamic range of [- 15, + 20] °C, the sensitivity increased to 2.4HU/°C (R2 = 0.50, p < 0.001). Using VMI reconstructions, the thermal sensitivity increased from 1.4 HU/°C at 70 keV to 1.5, 1.7 and 2.0HU/°C at 60, 50 and 40 keV, respectively (range [- 40, + 20] °C). For [- 15, + 20]°C, the thermal sensitivity increased from 2.4HU/°C at 70 keV to 2.5, 2.6 and 2.7HU/°C at 60, 50 and 40 keV, respectively. Both CT-values and noise also increased with decreasing VMI keV-levels.

CONCLUSION

During CT-guided cryoablation of porcine liver, low-keV VMI reconstructions derived from PCD-CT data sets exhibit improved thermal sensitivity being highest between + 20 and - 15 °C.

Anemia detection and quantification in contrast-enhanced CT scans on a novel photon-counting detector CT: A prospective proof-of-concept study

PURPOSE

To correlate CT values of the blood pool on VNC series with serum hemoglobin values for the detection of anemia in oncologic patients undergoing contrast-enhanced PCD-CT scans.

METHODS

This prospective study (NCT04989192) included consecutive oncologic patients undergoing contrast-enhanced CT on a novel PCD-CT system between 08/2021 and 01/2022. The interval between complete blood count (CBC) and CT scan acquisition had to be no more than seven days. CT-values of the blood pool were measured on 70 keV VMI series (CT-values(BP)70keV) and on VNC series (CT-values(BP)VNC) at five anatomic positions (left atrium, left ventricle, main pulmonary artery, ascending and descending aorta) and averaged per patient. Pearson correlation analyses and ROC analyses were performed to identify relations between CT-values(BP)VNC, CBC parameters, and degrees of anemia as defined by the WHO (no anemia, mild, moderate, severe anemia).

RESULTS

A total of 329 patients (age 68 ± 12 years; 200 men) were included. CT-values(BP)VNC showed a strong linear correlation to serum hemoglobin (r2 = 0.80, p <.001) and hematocrit (r2 = 0.76, p <.001) and were significantly different between anemia subgroups in both women and men (ΔHU: 3.5-11.4; all p <.01). ROC analyses yielded high diagnostic performance for the identification of patients without anemia, patients without and with mild anemia, and patients with severe anemia using gender-specific cutoffs for CT-value(BP)VNC (all AUC's > 0.90).

CONCLUSIONS

The spectral information inherent in PCD-CT acquisitions allows the detection and quantification of anemia in contrast-enhanced CT acquisitions of oncologic patients with high diagnostic accuracy.

German nation-wide in-patient treatment of abdominal aortic aneurysm-trends between 2005 and 2019 and impact of the SARS-CoV-2 pandemic

PURPOSE

Aim of this study was to analyze hospitalizations due to ruptured and non-ruptured abdominal aortic aneurysms (rAAA, nrAAA) in Germany between 2005 and 2021 to determine long-term trends in treatment and the impact of the SARS-CoV-2 pandemic.

MATERIALS AND METHODS

Fully anonymized data were available from the research data center (RDC) of the German Federal Statistical Office (Destatis). All German hospitalizations with the ICD-10 code "I71.3, rAAA" and "I71.4, nrAAA" in 2005 and 2010-2021 were analyzed.

RESULTS

We report data of a total of 202,951 hospitalizations. The number of hospitalizations increased from 2005 to 2019 (14,075 to 16,051, + 14.0%). The rate of open repair (OR) constantly decreased, whereas the rate of endovascular aortic repair (EVAR) increased until 2019. During the pandemic, the number of hospitalizations due to nrAAA dropped from 13,887 (86.5%) in 2019 to 11,278 (85.0%) in 2021. The strongest decrease of hospitalizations for AAA was observed during the first wave of the SARS-CoV-2-pandemic in spring 2020 (-25.5%).

CONCLUSION

Over the past decades, we observed an increasing number of hospitalizations due to AAA accompanied by a shift from OR to EVAR especially for nrAAA. During the lockdown measures due to the SARS-CoV-2-pandemic, a decrease in hospitalizations for nrAAA (but not for rAAA) was shown in 2020 and furthermore in 2021 with no rebound of treatment of nrAAA suggesting an accumulation of untreated AAA with a potentially increased risk of rupture.

Spectral metal artifact reduction after posterior spinal fixation in photon-counting detector CT datasets

PURPOSE

To investigate the usefulness of virtual monoenergetic image (VMI) reconstructions derived from scans on a novel photon-counting detector CT (PCD-CT) for artifact reduction in patients after posterior spinal fixation.

METHODS

This retrospective cohort study included 23 patients status post posterior spinal fixation. Subjects were scanned on a novel PCD-CT (NAEOTOM Alpha, Siemens Healthineers, Erlangen, Germany) as part of routine clinical care. 14 sets of VMI reconstructions were derived in 10 keV increments for the interval 60-190 keV. The mean and the standard deviation (SD) of CT-values in 12 defined locations around a pair of pedicle screws on one vertebral level and the SD of homogenous fat were measured and used to calculate an artifact index (AIx).

RESULTS

Averaged over all regions, the lowest AIx was observed at VMI levels of 110 keV (32.5 (27.8-37.9)) which was significantly different from those of VMIs ≤ 90 keV (p < 0.001) or ≥160 keV (p < 0.015), respectively. Overall AIx values increased in both lower- and higher-keV levels. Regarding individual locations, either a monotonous AIx-decrease for increasing keV values or an AIx-minimum in intermediate-keV levels (100-140 keV) was found. In locations adjacent to larger metal parts, the increase of AIx values at the high-end of the keV spectrum was mainly explained by a reappearance of streak artifacts.

CONCLUSION

Our findings suggest that 110 keV is the optimal VMI setting for overall artifact suppression. In specific anatomical regions, however, slight adjustments towards higher-keV levels may provide better results.

Evaluation of run-off computed tomography angiography on a first-generation photon-counting detector CT scanner - Comparison with low-kVp energy-integrating CT

PURPOSE

To assess the overall imaging performance (radiation dose and image quality) of a photon-counting detector CT (PCD-CT) in comparison with a state-of-the-art energy-integrating detector CT (EID-CT) in run-off CTAs.

METHODS

Consecutive patients who underwent run-off CTA on a PCD-CT were included (PCD-CT cohort). A retrospective cohort of patients who had undergone run-off CTA on an EID-CT was matched for gender, body mass index, height, and age (EID-CT cohort). Virtual monoenergetic imaging (VMI) reconstructions for various keV settings (40-120 keV) were generated. CT values and noise were semiautomatically measured for 13 vascular segments of the abdomen, pelvis, and lower extremities. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated for each segment. Subjective image quality was evaluated by two radiologists along the dimensions 'vessel attenuation', 'vessel sharpness', and 'overall image quality' using 5-point Likert scales.

RESULTS

Forty patients (age 70.9 ± 9.8 years; 14 women) were included in the PCD-CT cohort and matched with a corresponding number of EID-CT patients. Overall, there was an inverse correlation of signal and noise but also of SNR and CNR with keV levels used for VMI reconstructions. SNR and CNR in the 40 - 60 keV range exceeded EID-CT levels significantly. Subjective image quality was substantially higher at lower keV levels and showed no significant difference to EID-CT.

CONCLUSION

Low keV VMI reconstructions of run-off CTA scans on a PCD-CT result in substantially higher SNR and CNR than 80 kVp and 100 kVp EID-CT acquisitions with equal subjective image quality.

The In-Hospital Care of Patients With Peripheral Arterial Occlusive Disease

BACKGROUND

Studies from Denmark and the USA have shown differences in treatment outcomes for patients with peripheral arterial occlusive disease (PAOD) between hospitals of different size and certification status. For Germany, it is not known whether certification as a specialist center for vascular diseases or hospital size is associated with differences in the primary treatment outcome.

METHODS

Using data from the German Federal Statistical Office, all hospitalizations due to PAOD of Fontaine stage IIb or higher were included in our study and the hospitals were classified according to their size and certification status. PAOD stage, age, sex, and comorbidities were documented for each hospitalization. Univariate and multivariate logistic regressions were performed to identify independent variables that predict various treatment endpoints.

RESULTS

A total of 558 785 hospitalizations were included for analysis, of which 29% were in hospitals with certified vascular centers. In multivariate analysis, admissions to certified hospitals were associated with lower rates of major amputation (odds ratio [OR] 0.95, 95% confidence interval [0.92; 0.98], p = 0.003) and higher rates of minor amputation (OR 1.04 [1.01; 1.06], p = 0.004) with no difference observed in mortality (OR 0.99 [0.96; 1.03], p = 0.791). Admissions to larger hospitals were associated with more comorbidities, longer hospital stays, and higher rates of mortality and amputations.

CONCLUSION

Treatments in certified hospitals are associated with fewer major and more minor amputations. This may reflect intensification of therapy targeting preservation of functional limbs.

Impact of machine-learning-based coronary computed tomography angiography-derived fractional flow reserve on decision-making in patients with severe aortic stenosis undergoing transcatheter aortic valve replacement

OBJECTIVES

To evaluate feasibility and diagnostic performance of coronary CT angiography (CCTA)-derived fractional flow reserve (CT-FFR) for detection of significant coronary artery disease (CAD) and decision-making in patients with severe aortic stenosis (AS) undergoing transcatheter aortic valve replacement (TAVR) to potentially avoid additional pre-TAVR invasive coronary angiography (ICA).

METHODS

Consecutive patients with severe AS (n = 95, 78.6 ± 8.8 years, 53% female) undergoing pre-procedural TAVR-CT followed by ICA with quantitative coronary angiography were retrospectively analyzed. CCTA datasets were evaluated using CAD Reporting and Data System (CAD-RADS) classification. CT-FFR measurements were computed using an on-site machine-learning algorithm. A combined algorithm was developed for decision-making to determine if ICA is needed based on pre-TAVR CCTA: [1] all patients with CAD-RADS ≥ 4 are referred for ICA; [2] patients with CAD-RADS 2 and 3 are evaluated utilizing CT-FFR and sent to ICA if CT-FFR ≤ 0.80; [3] patients with CAD-RADS < 2 or CAD-RADS 2-3 and normal CT-FFR are not referred for ICA.

RESULTS

Twelve patients (13%) had significant CAD (≥ 70% stenosis) on ICA and were treated with PCI. Twenty-eight patients (30%) showed CT-FFR ≤ 0.80 and 24 (86%) of those were reported to have a maximum stenosis ≥ 50% during ICA. Using the proposed algorithm, significant CAD could be identified with a sensitivity, specificity, and positive and negative predictive value of 100%, 78%, 40%, and 100%, respectively, potentially decreasing the number of necessary ICAs by 65 (68%).

CONCLUSION

Combination of CT-FFR and CAD-RADS is able to identify significant CAD pre-TAVR and bears potential to significantly reduce the number of needed ICAs.

KEY POINTS

• Coronary CT angiography-derived fractional flow reserve (CT-FFR) using machine learning together with the CAD Reporting and Data System (CAD-RADS) classification safely identifies significant coronary artery disease based on quantitative coronary angiography in patients prior to transcatheter aortic valve replacement. • The combination of CT-FFR and CAD-RADS enables decision-making and bears the potential to significantly reduce the number of needed invasive coronary angiographies.

Anemia Detection by Hemoglobin Quantification on Contrast-enhanced Photon-counting CT Data Sets

See also the editorial by Dodd and MacDermott in this issue.

Optimal Conspicuity of Liver Metastases in Virtual Monochromatic Imaging Reconstructions on a Novel Photon-Counting Detector CT—Effect of keV Settings and BMI

In dual-energy CT datasets, the conspicuity of liver metastases can be enhanced by virtual monoenergetic imaging (VMI) reconstructions at low keV levels. Our study investigated whether this effect can be reproduced in photon-counting detector CT (PCD-CT) datasets. We analyzed 100 patients with liver metastases who had undergone contrast-enhanced CT of the abdomen on a PCD-CT (n = 50) or energy-integrating detector CT (EID-CT, single-energy mode, n = 50). PCD-VMI-reconstructions were performed at various keV levels. Identical regions of interest were positioned in metastases, normal liver, and other defined locations assessing image noise, tumor-to-liver ratio (TLR), and contrast-to-noise ratio (CNR). Patients were compared inter-individually. Subgroup analyses were performed according to BMI. On the PCD-CT, noise and CNR peaked at the low end of the keV spectrum. In comparison with the EID-CT, PCD-VMI-reconstructions exhibited lower image noise (at 70 keV) but higher CNR (for ≤70 keV), despite similar CTDIs. Comparing high- and low-BMI patients, CTDI-upregulation was more modest for the PCD-CT but still resulted in similar noise levels and preserved CNR, unlike the EID-CT. In conclusion, PCD-CT VMIs in oncologic patients demonstrated reduced image noise–compared to a standard EID-CT–and improved conspicuity of hypovascularized liver metastases at low keV values. Patients with higher BMIs especially benefited from constant image noise and preservation of lesion conspicuity, despite a more moderate upregulation of CTDI.

Comparison and Trends of Endovascular, Surgical and Hybrid Revascularizations and the Influence of Comorbidity in 1 Million Hospitalizations Due to Peripheral Artery Disease in Germany Between 2009 and 2018

Objective

To analyze trends and differences of endovascular, surgical and hybrid revascularization approaches and the impact of comorbidity on characteristics, costs, and outcome of in-patients with peripheral artery disease (PAD) of the lower extremity.

Methods

Analyzing data provided by the Research Data Center of the German Federal Statistical Office, we included all hospitalizations due to PAD Fontaine IIb (Rutherford 2–3) or higher in Germany between 2009–2011 and 2016–2018. According to the individually performed procedures encoded by the Operation and Procedure Classification System, we divided hospitalizations by revascularization procedures into sole endovascular, sole surgical, hybrid, two-step and no revascularization. Patient’s comorbidity was assessed using the linear van Walraven comorbidity score (vWs).

Results

1,067,671 hospitalizations (mean age 71.3 ± 11.1 years; 60.1% male) were analyzed. Between 2009–2011 and 2016–2018, reimbursement costs rose by 28.0% from €2.72 billion (€5,350/case) to €3.49 billion (€6,238/case). The share of hospitalizations with any revascularization increased by 8.9% (67.7–73.7%) driven by an increase in two-step (+ 63.3%), hybrid (+ 58.2%) and sole endovascular revascularizations (+ 32.6%), while sole surgical approaches declined (− 18.2%). Hospitalizations of more comorbid patients (vWs ≥ 20) rose by 46.8% (21,444–31,478 cases), showed an overproportionate increase in costs of 124.6% (+ €1,750/case) and were associated with more individual procedures (+ 90.6%).

Conclusions

In-patient treatment of PAD patients shows increasing numbers of hybrid and sole endovascular revascularizations and more patients with higher comorbidity, while sole surgical interventions and in-hospital mortality decrease. Consequently, associated costs are surging especially in more comorbid patients due to an increasing number of performed procedures and escalation of therapy.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00270-022-03136-9.

Virtual Non-Contrast Reconstructions of Photon-Counting Detector CT Angiography Datasets as Substitutes for True Non-Contrast Acquisitions in Patients after EVAR-Performance of a Novel Calcium-Preserving Reconstruction Algorithm

The purpose of this study was to evaluate virtual-non contrast reconstructions of Photon-Counting Detector (PCD) CT-angiography datasets using a novel calcium-preserving algorithm (VNCPC) vs. the standard algorithm (VNCConv) for their potential to replace unenhanced acquisitions (TNC) in patients after endovascular aneurysm repair (EVAR). 20 EVAR patients who had undergone CTA (unenhanced and arterial phase) on a novel PCD-CT were included. VNCConv- and VNCPC-series were derived from CTA-datasets and intraluminal signal and noise compared. Three readers evaluated image quality, contrast removal, and removal of calcifications/stent parts and assessed all VNC-series for their suitability to replace TNC-series. Image noise was higher in VNC- than in TNC-series (18.6 ± 5.3 HU, 16.7 ± 7.1 HU, and 14.9 ± 7.1 HU for VNCConv-, VNCPC-, and TNC-series, p = 0.006). Subjective image quality was substantially higher in VNCPC- than VNCConv-series (4.2 ± 0.9 vs. 2.5 ± 0.6; p < 0.001). Aortic contrast removal was complete in all VNC-series. Unlike in VNCConv-reconstructions, only minuscule parts of stents or calcifications were erroneously subtracted in VNCPC-reconstructions. Readers considered 95% of VNCPC-series fully or mostly suited to replace TNC-series; for VNCConv-reconstructions, however, only 75% were considered mostly (and none fully) suited for TNC-replacement. VNCPC-reconstructions of PCD-CT-angiography datasets have excellent image quality with complete contrast removal and only minimal erroneous subtractions of stent parts/calcifications. They could replace TNC-series in almost all cases.

Visualization of bone details in a novel photon-counting dual-source CT scanner-comparison with energy-integrating CT

Objectives

Photon-counting detector CT (PCD-CT) promises a leap in spatial resolution due to smaller detector pixel sizes than implemented in energy-integrating detector CTs (EID-CT). Our objective was to compare the visualization of smallest bone details between PCD-CT and EID-CT using a mouse as a specimen.

Materials and methods

Two euthanized mice were scanned at a 20-slice EID-CT and a dual-source PCD-CT in single-pixel mode at various CTDI_Vol values. Image noise and signal-to-noise ratio (SNR) were evaluated using repeated ROI measurements. Edge sharpness of bones was compared by the maximal slope within CT value plots along sampling lines intersecting predefined bones of the spine. Two readers evaluated bone detail visualization at four regions of the spine on a three-point Likert scale at various CTDI_Vol’s. Two radiologists selected the series with better detail visualization among each of 20 SNR-matched pairs of EID-CT and PCD-CT series.

Results

In CTDI_Vol-matched scans, PCD-CT series showed significantly lower image noise (Noise_CTDI=5 mGy: 16.27 ± 1.39 vs. 23.46 ± 0.96 HU, p < 0.01), higher SNR (SNR_CTDI=5 mGy: 20.57 ± 1.89 vs. 14.00 ± 0.66, p < 0.01), and higher edge sharpness (Edge Slope_{lumbar spine}: 981 ± 160 vs. 608 ± 146 HU/mm, p < 0.01) than EID-CT series. Two radiologists considered the delineation of bone details as feasible at consistently lower CTDI_Vol values at PCD-CT than at EID-CT. In comparison of SNR-matched reconstructions, PCD-CT series were still considered superior in almost all cases.

Conclusions

In this head-to-head comparison, PCD-CT showed superior objective and subjective image quality characteristics over EID-CT for the delineation of tiniest bone details. Even in SNR-matched pairs (acquired at different CTDI_Vol’s), PCD-CT was strongly preferred by radiologists.

Key Points

• In dose-matched scans, photon-counting detector CT series showed significantly less image noise, higher signal-to-noise ratio, and higher edge sharpness than energy-integrating detector CT series.

• Human observers considered the delineation of tiny bone details as feasible at much lower dose levels in photon-counting detector CT than in energy-integrating detector CT.

• In direct comparison of series matched for signal-to-noise ratio, photon-counting detector CT series were considered superior in almost all cases.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00330-021-08441-4.

In-patient care trends in peripheral artery disease in the German healthcare system over the past decade

OBJECTIVES

To analyze trends of in-hospital treatment of patients admitted due to peripheral artery disease (PAD) from 2009 to 2018 with special focus on comorbidities, revascularization procedures, resulting costs, and outcome.

METHODS

Using data from the research data center of the German Federal Statistical Office, we included all hospitalizations due to PAD Fontaine stage IIb or higher from 2009 to 2018. To analyze comorbidities, Elixhauser diagnostic groups and linear van Walraven score (vWS) were assessed.

RESULTS

A total of 1.8 million hospitalizations resulting in €10.3 billion in reimbursement costs were included. From 2009 to 2018, the absolute number of hospitalizations due to PAD increased by 13.3% (163,547 to 185,352). The average cost per hospitalization increased by 20.8% from €5,261 to €6,356. The overall in-hospital mortality decreased from 3.1 to 2.6%. Median vWS of all PAD cases increased by 3 points (2 to 5). The number of percutaneous transluminal angioplasties (PTA) increased by 43.9% while some surgical procedures such as bypasses and embolectomies decreased by 30.8% and 6.8%, respectively. Many revascularization procedures showed a disproportionate increase of those performed in vessels below the knee for example in PTA (+ 68.5%) or in endarterectomies (+ 38.8%).

CONCLUSIONS

This decade-long nationwide analysis shows a rising number of hospitalizations due to PAD with more comorbid patients resulting in increasing reimbursement costs. Interventions are shifting from surgical to endovascular approaches with a notable trend towards interventions in smaller vessels below the knee.

KEY POINTS

• The number of hospitalizations due to peripheral artery disease is rising and it is associated with increasing reimbursement costs. • Admitted patients are older and show an increasing number of comorbidities while overall in-hospital mortality is decreasing. • Revascularization procedures are shifting from surgical to endovascular approaches and show a trend towards intervention in smaller vessels below the knee. • Major amputations are decreasing while the number of minor amputations is increasing.

Non-operative management of blunt splenic trauma: The role of splenic artery embolization depending on the severity of parenchymal injury

PURPOSE

To address the disagreement about the need for splenic artery embolization (SAE) in medium grade blunt splenic trauma this retrospective study evaluates the clinical outcome of non-operative management (NOM) and the possible impact of a more liberal indication for primary SAE.

METHOD

From 01/2010 to 12/2019 186 patients presented with splenic injury on computed tomography (CT) after blunt abdominal trauma. The extent of splenic injuries according to Marmery, vascular pathologies, active bleeding as well as clinical and laboratory parameters were recorded and analyzed with regard to the success rates of NOM and SAE. Procedural complications and clinical outcome were noted. The number needed to treat (NNT) was determined for a possible extension of the indication for SAE to grade 3 injuries.

RESULTS

Of 186 patients 126 were managed non-operatively, 47 underwent primary SAE and twelve splenectomy. NOM was successful in 119/126 (94 %) patients. Conversion rate was significantly higher in patients with active bleeding or vascular pathology. Patients with failed NOM had a significantly greater decrease in haemoglobin and haematocrit levels. Primary SAE was successful in 45/47 (96 %) cases. Major complications occurred in four cases (9%), all managed without sequela. The NNT in grade 3 splenic injuries equals 13.

CONCLUSIONS

NOM of low to medium-grade blunt splenic trauma has a low failure rate. Presence of active haemorrhage is the most important predictor for failure of NOM. SAE should be reserved for high-grade injuries and visible vascular pathology or active bleeding to avoid a disproportionate increase in the NNT.

Ventilation/perfusion SPECT/CT in patients with pulmonary emphysema. Evaluation of software-based analysing

The purpose of this study was to evaluate the reproducibility of a new software based analysing system for ventilation/perfusion single-photon emission computed tomography/computed tomography (V/P SPECT/CT) in patients with pulmonary emphysema and to compare it to the visual interpretation.

PATIENTS, MATERIAL AND METHODS

19 patients (mean age: 68.1 years) with pulmonary emphysema who underwent V/P SPECT/CT were included. Data were analysed by two independent observers in visual interpretation (VI) and by software based analysis system (SBAS). SBAS PMOD version 3.4 (Technologies Ltd, Zurich, Switzerland) was used to assess counts and volume per lung lobe/per lung and to calculate the count density per lung, lobe ratio of counts and ratio of count density. VI was performed using a visual scale to assess the mean counts per lung lobe. Interobserver variability and association for SBAS and VI were analysed using Spearman's rho correlation coefficient.

RESULTS

Interobserver agreement correlated highly in perfusion (rho: 0.982, 0.957, 0.90, 0.979) and ventilation (rho: 0.972, 0.924, 0.941, 0.936) for count/count density per lobe and ratio of counts/count density in SBAS. Interobserver agreement correlated clearly for perfusion (rho: 0.655) and weakly for ventilation (rho: 0.458) in VI.

CONCLUSIONS

SBAS provides more reproducible measures than VI for the relative tracer uptake in V/P SPECT/CTs in patients with pulmonary emphysema. However, SBAS has to be improved for routine clinical use.

Ventilation/perfusion SPECT or SPECT/CT for lung function imaging in patients with pulmonary emphysema?

PURPOSE

To evaluate the utility of attenuation correction (AC) of V/P SPECT images for patients with pulmonary emphysema.

MATERIALS AND METHODS

Twenty-one patients (mean age 67.6 years) with pulmonary emphysema who underwent V/P SPECT/CT were included. AC/non-AC V/P SPECT images were compared visually and semiquantitatively. Visual comparison of AC/non-AC images was based on a 5-point likert scale. Semiquantitative comparison assessed absolute counts per lung (aCpLu) and lung lobe (aCpLo) for AC/non-AC images using software-based analysis; percentage counts (PC = (aCpLo/aCpLu) × 100) were calculated. Correlation between AC/non-AC V/P SPECT images was analyzed using Spearman's rho correlation coefficient; differences were tested for significance with the Wilcoxon rank sum test.

RESULTS

Visual analysis revealed high conformity for AC and non-AC V/P SPECT images. Semiquantitative analysis of PC in AC/non-AC images had an excellent correlation and showed no significant differences in perfusion (ρ = 0.986) or ventilation (ρ = 0.979, p = 0.809) SPECT/CT images.

CONCLUSION

AC of V/P SPECT images for lung lobe-based function imaging in patients with pulmonary emphysema do not improve visual or semiquantitative image analysis.

Uterine artery embolization in single symptomatic leiomyoma: do anatomical imaging criteria predict clinical presentation and long-term outcome?

BACKGROUND

Uterine artery embolization (UAE) has proven to be an effective treatment alternative for women suffering from symptomatic uterine leiomyomas. However, long-term clinical evaluation reveals treatment failure in approximately 25% of patients. To cope with the great variability in the extent of leiomyoma disease former studies are based on the simplifying assumption that the largest leiomyoma mainly causes the symptoms.

PURPOSE

To evaluate whether anatomical characteristics in women with a single symptomatic leiomyoma influence clinical presentation and outcome after UAE.

MATERIAL AND METHODS

Ninety-one patients with a single leiomyoma underwent UAE. Age, uterine and fibroid volume, fibroid location, and clinical symptoms (bleeding- and/or bulk-related symptoms) were documented. The need for reinterventions (i.e. repeat UAE, hysterectomy, myomectomy) and unchanged or worsened symptoms after UAE were classified as treatment failure (TF). Contrast-enhanced magnetic resonance imaging (MRI) 48-72 h after UAE was available in 38 women. The rate of fibroid infarction was determined and patients were assigned to one of three groups: complete (100%), almost complete (90-99%), or partial infarction (<90%). Cox regression analysis (CRA) was used to determine the influence of morphological and clinical parameters on outcome.

RESULTS

Follow-up was available in 79/91 (87%) women (median age, 42 years; range, 33-56 years) at a median of 5 years (range, 3.1-9.2 years) after UAE. Anatomical leiomyoma criteria neither connected to specific clinical presentation nor influenced clinical outcome. Younger women showed a higher risk for TF with every year older lowering the risk by the factor of 0.86 (P = 0.024). Subgroup analysis showed predictive value of fibroid infarction with a cumulative survival free from TF of 91% for complete vs. 0% for partial infarction (P < 0.001).

CONCLUSION

Even in women with single leiomyomas, anatomical criteria do not specify clinical presentation or predict clinical outcome. Younger patient age and incomplete fibroid infarction relate to higher rates of TF.

Clinical long-term outcome after uterine artery embolization: sustained symptom control and improvement of quality of life

PURPOSE

To evaluate long-term clinical efficacy of uterine artery embolization (UAE) for uterine fibroids with respect to symptom control and improvement in quality of life.

MATERIALS AND METHODS

Between October 2000 and October 2007, 380 consecutive women underwent UAE. To determine long-term efficacy, the rate of reinterventions (ie, repeat UAE, hysterectomy, myomectomy) and the clinical response regarding symptoms related to bleeding and bulk were documented. Persistence, worsening, or recurrence of symptoms and reinterventions were classified as treatment failure (TF). The cumulative rate of freedom from TF was determined by Kaplan-Meier analysis. Cox regression was used to identify possible clinical or morphologic predictors of outcome. Secondary outcome measures were changes in disease-specific quality of life and onset of menopause.

RESULTS

Follow-up was available for a median of 5.7 years (range, 3.1-10.1 y) after treatment in 304 of 380 (80%) patients. There were 54 TFs with subsequent reintervention in 46 women. Kaplan-Meier analysis revealed a cumulative TF rate of 23.3% after 10 years. Cox regression demonstrated a significantly higher likelihood of TF in patients<40 years old compared with patients>45 years old (hazard ratio, 2.28; P = .049). Women without TF showed sustained normalization of disease-specific quality of life (P <.001). Cessation of menstruation at a median age of 51 years was reported by 57 (22.8%) of 250 women.

CONCLUSIONS

UAE leads to long-term control of fibroid-related symptoms and normalization of quality of life in approximately 75% of patients. Younger women seem to have a higher risk of TF than older women closer to menopause.

Impact of Ga-68 DOTATOC PET/CT on the diagnosis and treatment of patients with multiple endocrine neoplasia

PURPOSE

To evaluate the impact of Ga-68 DOTATOC PET/CT on diagnosis and therapeutic management of patients with multiple endocrine neoplasia (MEN).

MATERIALS AND METHODS

We did 28 Ga-68 DOTATOC PET/CT in 21 MEN patients (10 female, 11 men; mean age 41.3 years). 109 lesions detected were classified into MEN-associated lesions [i.e., neuroendocrine tumors (NET)] and non-MEN-associated lesions for PET, CT, and PET/CT. The impact of Ga-68 DOTATOC PET/CT on diagnosis and therapeutic management of patients with MEN were assessed by the records of the interdisciplinary NET tumor board including histopathological findings, clinical and radiological follow-up.

RESULTS

Ga-68 DOTATOC PET/CT had an impact on diagnosis and therapeutic management in 10/21 (47.6%) MEN patients. For detecting NET lesions in MEN patients Ga-68 DOTATOC PET/CT reached a sensitivity/specificity of 91.7%/93.5%. There was a significant difference for the detection rate between Ga-68 DOTATOC PET/CT and CT alone (p < 0.001) both using contrast-agent (p = 0.002) or not (p < 0.001) and also a significant difference between contrast-enhanced (CE-) CT and non-CE-CT alone (p = 0.006).

CONCLUSIONS

GA-68 DOTATOC PET/CT allows a high detection rate of NET lesions in the context of MEN-1 syndrome as well as influence therapeutic management in nearly up to half of the patients. GA-68 DOTATOC PET/CT should include a CE-CT to improve MEN-associated NET lesion detection.

Ischemic-type biliary lesions after ortothopic liver transplantation: diagnosis with magnetic resonance cholangiography

PURPOSE

To determine the accuracy of magnetic resonance (MR) cholangiography for detection of ischemic-type biliary lesions (ITBL) following orthotropic liver transplantation (OLT).

MATERIALS AND METHODS

MR cholangiography was performed in 16 patients with established diagnosis of ITBL following OLT. Two blinded observers reviewed all images in consensus and recorded diagnostic features including presence of intrahepatic and extrahepatic biliary strictures, dilatations, beading, pruning, and filling defects. Sensitivity, specificity, positive predictive value, and accuracy of MR cholangiography were calculated. Final diagnosis was established at endoscopic retrograde cholangiography.

RESULTS

MR cholangiography proved to be a valuable tool for the detection of stenoses and dilatations in patients with ITBL following OLT. Sensitivity of the different diagnostic features ranged between 71% and 100%, specificity between 50% and 100%, accuracy between 81% and 100%, and positive predictive value between 87% and 100%.

CONCLUSION

MR cholangiography proved to be an accurate imaging technique to noninvasively detect biliary complications in patients with ITBL after OLT.

Uterine artery embolization for leiomyomas: percentage of infarction predicts clinical outcome

PURPOSE

To determine the effect of partial versus complete leiomyoma infarction on relief of leiomyoma-related symptoms and freedom from invasive reinterventions and to assess if patient age, location of the dominant leiomyoma, number of leiomyomas, or baseline uterine and dominant leiomyoma volume were associated with clinical failure.

MATERIALS AND METHODS

Study protocol was approved by the institutional review board, and informed consent was obtained. One hundred fifteen consecutive women (median age, 42 years; range, 34-61 years) with symptomatic uterine leiomyomas underwent contrast material-enhanced magnetic resonance (MR) imaging at baseline and 24-72 hours after uterine artery embolization (UAE) to determine the percentage of infarction of leiomyoma tissue (complete = 100%, almost complete = 90%-99%, and partial = 0%-89%). Clinical outcome and frequency of reinterventions were compared for up to 36 months.

RESULTS

One hundred thirteen patients completed at least one clinical follow-up. Twenty-four months after UAE, 50% +/- 15.2 (standard error) of the patients with partial infarction and 80% +/- 13.4 (standard error) of patients with almost complete infarction had undergone no reintervention. No patient with complete infarction needed a second treatment (P < .001). The hazard ratios for reintervention between the complete infarction group and the almost complete and partial infarction groups were 15.88 (95% confidence interval [CI]: 1.22, 2225.54; P = .034) and 73.08 (95% CI: 8.33, 9636.35; P < .001), respectively. There were significant differences in hazard ratios between patients with partial and those with complete infarction for persistence or recurrence of menorrhagia (hazard ratio, 7.45; 95% CI: 2.08, 28.31; P = .002) and bulk-related symptoms (hazard ratio, 5.90; 95% CI: 1.66, 21.92; P = .007). There was no significant correlation between patient age, number of leiomyomas, location of the dominant leiomyoma, or baseline uterine and dominant leiomyoma volume and clinical failure.

CONCLUSION

Women with leiomyoma infarction above 90% on contrast-enhanced MR images after UAE show significantly better symptom control and fewer reinterventions than do patients with a lower infarction rate.

Acrylamido polyvinyl alcohol microspheres for uterine artery embolization: 12-month clinical and MR imaging results

PURPOSE

To report the 12-month clinical and magnetic resonance (MR) imaging results of an ongoing two-center registry involving acrylamido polyvinyl alcohol (PVA) microspheres for uterine artery embolization (UAE) for leiomyomas.

MATERIALS AND METHODS

A total of 69 patients underwent UAE with 500-700-microm, 700-900-microm, and 900-1,200-mum acrylamido PVA microspheres (BeadBlock). Thirty-three patients underwent UAE with a limited embolization (protocol A) and 36 patients underwent UAE with stasis as the angiographic endpoint (protocol B). Primary objectives were clinical efficacy measured by a leiomyoma-specific quality of life (QOL) questionnaire and infarction rate of leiomyomas on early contrast agent-enhanced MR imaging. Secondary objectives were in-hospital complications, patient satisfaction, and frequency of clinical failure.

RESULTS

Bilateral embolization was technically successful in 68 of 69 patients. A significant decrease (P < .001) in symptom severity and increase in health-related QOL was observed at 3 and 12 months with no significant differences between embolization protocols. However, contrast agent-enhanced MR imaging showed a significantly lower rate of completely infarcted leiomyomas in protocol A compared with protocol B (P < .05). Early clinical failures in patients treated according to protocol A were caused by incomplete tumor infarction. Minor complications occurred in five of 69 patients. Patient satisfaction was similar between protocols.

CONCLUSIONS

Acrylamido PVA microspheres are a clinically effective and safe embolic agent for UAE. The use of 500-700-microm spheres and a limited embolization results in an unacceptably high rate of failed tumor infarction. Superior imaging results and fewer repeat interventions can be achieved with use of 700-900-microm spheres and stasis as the angiographic endpoint.

Uterine artery embolization for symptomatic adenomyosis with or without uterine leiomyomas with the use of calibrated tris-acryl gelatin microspheres: midterm clinical and MR imaging follow-up

PURPOSE

To evaluate clinical and magnetic resonance (MR) imaging results after uterine artery embolization (UAE) in women with symptomatic adenomyosis with or without uterine leiomyomas.

MATERIALS AND METHODS

Thirty-eight women with symptomatic adenomyosis with or without uterine leiomyomas were treated with UAE with calibrated tris-acryl gelatin microspheres. Based on MR findings, women were categorized as having pure adenomyosis (group A; n = 15), adenomyosis dominance with fibroid tumors (group B; n = 14), or fibroid tumor dominance with adenomyosis (group C; n = 9).

RESULTS

Heavy menstrual bleeding, pain, and bulk-related symptoms at last follow-up at a median of 16.5 months (range, 3-38 months) were compared with baseline symptoms. With follow-up MR imaging at a median of 12 months (range, 3-36 months), changes in uterine volume, leiomyoma volume, junctional zone thickness, and contrast enhancement of adenomyosis were assessed. After embolization, adenomyosis infarction could be depicted on contrast medium-enhanced MR in 44.1% of cases. Median reductions of uterine volume, fibroid tumor volume, and junctional zone thickness were 44.8%, 77.1%, and 23.9%, respectively. In group A, three patients needed additional surgery after UAE, in addition to two in group B and one in group C. In the remaining 32 patients, except for one patient in group C, all preexisting symptoms (eg, bleeding, pain, bulk-related symptoms) improved or resolved after UAE. Overall, 84.2% of women were satisfied with the results of UAE.

CONCLUSION

In this study, midterm results (at a median of 16.5 months) showed that UAE in symptomatic adenomyosis with or without uterine leiomyomas is effective. Hysterectomy was avoided in the vast majority of patients. MR imaging showed reduction of uterine volume and junctional zone thickness.

Use of the 4F Rösch Inferior Mesenteric Catheter in Embolization Procedures in the Pelvis: A Review of 300 Cases

The aim of this study is to evaluate the use of a 4F Rösch inferior mesenteric (RIM) catheter for pelvic embolization procedures. Between October 2000 and January 2006, 364 patients (357 female, 7 male; age: 23-67 years) underwent embolization of various pathologies [uterine fibroids (n = 324), pure adenomyosis of the uterus (n = 19), postpartum hemorrhage (n =1), traumatic or postoperative hemorrhage (n = 9), bleeding related to cervical cancer (n =7), AV malformation of the uterus (n = 2) and high-flow priapism (n = 2)] at a single institution. In all cases, bilateral catheterization was primarily attempted with the use of a 4F hook-shaped braided endhole catheter (Rösch-Inferior-Mesenteric, RIM-Catheter, Cordis, Miami, FL). Frequency of initial failure to catheterize the vascular territory of interest and carry out the embolization were recorded and the types of difficulty encountered were noted. Catheterization of the main stem of the vessel territory of interest with the use of a unilateral femoral approach and the 4F RIM catheter was successful in 334/364 (91.8%) the embolization cases. Bilateral catheterization of the internal iliac arteries using a single common femoral artery access and the 4F RIM catheter was achieved in 322/364 (88.5%) patients. In 12/364 (3.3%) patients, a contralateral puncture was performed and the same 4F catheter was used. In 28/364 (7.7%) cases the 4F RIM catheter was exchanged for a catheter with a cobra-shaped or sidewinder configuration. The 4F RIM catheter is a simple and valuable alternative to catheters and techniques commonly employed for pelvic artery embolization.

Gadobenate dimeglumine-enhanced MR angiography: Diagnostic performance of four doses for detection and grading of carotid, renal, and aorto-iliac stenoses compared to digital subtraction angiography

PURPOSE

To determine the diagnostic performance of contrast-enhanced MR angiography (CE-MRA) with four doses of gadobenate dimeglumine for detection of significant steno-occlusive disease of the carotid, renal, and pelvic vasculature.

MATERIALS AND METHODS

Eighty-four patients with suspected disease of the renal (n = 16), pelvic (n = 41), or carotid (n = 27) arteries underwent CE-MRA (3D-spoiled gradient-echo sequences) at 1.5T. CE-MRA was performed with gadobenate dimeglumine at 0.025, 0.05, 0.1, or 0.2 mmol/kg (23, 24, 19, and 18 patients, respectively) administered at 2 mL/sec. Accuracy, sensitivity, specificity, and positive and negative predictive values (PPV and NPV, respectively) for detection of significant disease (>50% stenosis or occlusion for renal/pelvic arteries; >70% stenosis or occlusion for carotid arteries) was determined by three fully blinded, independent radiologists using conventional digital subtraction angiography (DSA) as reference standard. All comparisons were tested statistically (ANOVA, chi-square, and Mantel-Haenszel tests as appropriate) and reader agreement (kappa) was assessed.

RESULTS

Values for accuracy, sensitivity, specificity, PPV, and NPV on CE-MRA were consistently higher for 0.1 mmol/kg gadobenate dimeglumine (accuracy = 95.2-97.3%, sensitivity = 84.2% (all readers), specificity = 96.9-99.2%, PPV = 80.0-94.1%, NPV = 97.6-97.7%). The greater accuracy of the 0.1 mmol/kg dose was significant (P < 0.01, all readers) compared to all other dose groups. Agreement between the three readers was good for all dose groups (kappa >/=0.58), with the highest percent agreement (85.7%) noted for the 0.1 mmol/kg dose.

CONCLUSION

Significantly better diagnostic performance on CE-MRA of the renal, pelvic, and carotid arteries is achieved with a gadobenate dimeglumine dose of 0.1 mmol/kg bodyweight.

Uterine Fibroids: Contrast-enhanced MR Angiography to Predict Ovarian Artery Supply—Initial Experience

PURPOSE

To prospectively evaluate the diagnostic performance of contrast material-enhanced magnetic resonance (MR) angiography in helping predict ovarian artery supply of uterine fibroids by using postembolization conventional aortography as the reference standard.

MATERIALS AND METHODS

The protocol for the study was approved by the institutional review board, and each patient gave informed consent. Ninety consecutive women (mean age, 42.5 years; range, 33-63 years) underwent MR angiography before uterine artery embolization (UAE). The number and origin of the ovarian arteries were determined. Ovarian artery supply of fibroids was graded as very unlikely, possible, or very likely by using a scoring system based on a combination of MR angiographic findings. MR angiographic results were compared with those of conventional aortography performed after UAE in all patients and followed by selective angiography in case of a suspected ovarian artery supply of fibroids. Analysis of the association between MR angiographic grading and conventional angiography as the standard of reference was performed with a chi(2) trend test. Sensitivity and specificity, including exact 95% confidence intervals (CIs), of MR angiography were determined.

RESULTS

MR angiography depicted 18 ovarian arteries (four bilateral, 10 unilateral), one with an atypical origin. Five ovarian arteries were classified as very likely; three, as possible; and 10, as very unlikely sources of arterial fibroid supply. Seven (39%) of 18 ovarian arteries detected at MR angiography were visible at conventional aortography. Fibroid supply was verified at selective angiography in five ovarian arteries in five (6%) of 90 patients. There was a strong association between MR angiographic grading and the results of conventional angiography (P = .002). Sensitivity of MR angiography in depicting ovarian artery supply (grade, possible or very likely) was 100% (five of five, 95% CI: 48%; 100%) and specificity was 77% (10 of 13, 95% CI: 46%; 95%).

CONCLUSION

Contrast-enhanced MR angiography can help predict ovarian artery supply of uterine fibroids.

Magnetic resonance cholangiopancreatography using a free-breathing T2-weighted turbo spin-echo sequence with navigator-triggered prospective acquisition correction

PURPOSE

The objective of this study was to evaluate the image quality of a respiratory-triggered T2-weighted (T2w) turbo spin-echo (TSE) sequence for magnetic resonance cholangiopancreatography (MRCP) using a new method for respiratory triggering by tracking the motion of the right diaphragm [prospective acquisition correction (PACE) technique].

MATERIALS AND METHODS

Fifty consecutive patients underwent MRCP imaging applying breath-hold half-Fourier single-shot TSE sequences and the respiratory-triggered T2w TSE sequence. Qualitative evaluation grading the depiction of eight segments of the pancreaticobiliary tree and the frequency of artifacts was performed. Quantitative evaluation included calculation of the relative contrast (RC) between fluid-filled ductal structures and organ parenchyma at four segments.

RESULTS

A significantly higher (P<.01) RC was measured for the respiratory-triggered T2w TSE sequence [maximum intensity projection (MIP)] for all of the four investigated segments (one of four segments for the MIP) of the pancreaticobiliary tree, as well as a significant (P<.01) improvement of visualization of all ductal segments compared with the breath-hold sequences. The frequency of artifacts was significantly lower (P<.01) compared with the breath-hold sequences.

CONCLUSION

Respiratory-triggered MRCP using a T2w TSE sequence with PACE significantly improves image quality and may be included into the routine MRCP sequence protocol.

Uterine Arterial Embolization With Tris-acryl Gelatin Microspheres

Uterine artery embolization (UAE) as an alternative to surgery for the treatment of uterine fibroids and adenomyosis uteri became increasingly popular. While the clinical success of this new treatment strategy is without doubt, there is still considerable uncertainty with respect to the morphologic changes induced by UAE. In this study, a total of 173 women were treated with UAE using tris-acryl gelatin microspheres (TGMS), a new particulate spherical embolic agent, for either symptomatic adenomyosis or leiomyoma. Surgical specimens of 8 women who underwent subsequent myomectomy or hysterectomy were evaluated by conventional histology and immunohistochemistry. TGMS were readily apparent in both macroscopy and routine histology. In patients with fibroids, TGMS accumulated in medium-sized vessels in the direct tumor vicinity, a minor fraction of particles was detected in the outer half of the myometrium and within leiomyomata. In patients with adenomyosis, a random distribution of TGMS was noted throughout the outer half of the myometrium. Freshly infused particles occluded the respective arteries without a significant tissue reaction. In the course of time, a granulomatous foreign body reaction in the vicinity of particles occurred, eventually followed by complete vessel destruction. Leiomyoma treated with UAE showed either hyaline necrosis, coagulative necrosis, or no change at all. Foci of adenomyosis remained unaltered. In conclusion, after UAE with TGMS, particles were identified predominately but not exclusively at the periphery of fibroids. Pathologists must be aware of the morphologic changes induced by UAE in leiomyoma to avoid misinterpretation of induced tissue alterations as signs of malignant tumor growth.

Magnetic resonance imaging of the upper abdomen using a free-breathing T2-weighted turbo spin echo sequence with navigator triggered prospective acquisition correction

PURPOSE

To evaluate a free-breathing navigator triggered T2-weighted turbo spin-echo sequence with prospective acquisition correction (T2w-PACE-TSE) for MRI of the upper abdomen in comparison to a conventional T2-weighted TSE (T2w-CTSE), a single-shot TSE (T2w-HASTE), and a T1-weighted gradient-echo sequence (T1w-FLASH).

MATERIALS AND METHODS

A total of 40 consecutive patients were examined at 1.5 T using free-breathing T2w-PACE-TSE, free-breathing T2w-CTSE, and breath-hold T2w-HASTE and T1w-FLASH acquisition. Images were evaluated qualitatively by three radiologists regarding motion artifacts, liver-spleen contrast, depiction of intrahepatic vessels, the pancreas and the adrenal glands, and overall image quality on a four-point scale. Quantitative analysis of the liver-spleen contrast was performed.

RESULTS

Depiction and sharpness of intrahepatic vessels were rated significantly better (P < 0.01) using T2w-PACE-TSE compared to T2w-CTSE and T2w-HASTE sequences. Significantly higher contrast values were measured for T2w-PACE-TSE images compared to T2w-CTSE, T2w-HASTE, and T1w-FLASH images (P < 0.01). Mean examination time of the T2w-PACE-TSE was 7.91 minutes, acquisition time of the T2w-CTSE sequence was 4.52 minutes.

CONCLUSION

Prospective acquisition correction is an efficient method for reducing respiratory movement artifacts in T2w-TSE imaging of the upper abdomen. Compared to T2w-CTSE and T2w-HASTE sequences recognition of anatomical details and contrast can be significantly improved.

Quantification of Functional Mitral Valve Regurgitation in Patients With Congestive Heart Failure

OBJECTIVES

We sought to determine the agreement between electron-beam computed tomography (CT) and cardiac catheterization for the quantification of mitral regurgitation and to evaluate their association with echocardiographic assessment.

MATERIAL AND METHODS

Fifty patients with congestive heart failure were examined both by electron-beam CT and catheterization to calculate mitral regurgitation volume and fraction based on the difference between the left ventricular stroke and aortic flow volume. The severity of regurgitation was also compared with visual assessment by echocardiography (grade, 0-4+).

RESULTS

The mean values for the mitral regurgitation volume and fraction did not differ significantly between electron-beam CT and catheterization (mean differences: 0.2 mL/m2 and -0.9%, P > 0.05 each, limits of agreement: -14.0 to 14.4 mL/m2 and -26.3 to 24.5%, respectively) and showed a good correlation (r = 0.79 and r = 0.76, respectively; P < 0.05 each). Good levels of correlation were observed between echocardiographic severity grading and quantitative measurements of regurgitation volume and fraction, which were somewhat better between echocardiography and electron-beam CT (rS = 0.78 and rS = 0.84, respectively; P < 0.05 each) than between echocardiography and catheterization (rS = 0.72 and rS = 0.81, respectively; P < 0.05 each).

CONCLUSION

Our results suggest that electron-beam CT allows for quantification of mitral valve regurgitation with similar accuracy as cardiac catheterization. Measurements with both modalities correlated well with the results of echocardiographic assessment.

Covered transjugular intrahepatic portosystemic stents maintain lower portal pressure and require fewer reinterventions than uncovered stents

BACKGROUND

The purpose of this study was to evaluate the patency, functional and haemodynamic results of expanded-polytetrafluoroethylene (ePTFE)-covered transjugular intrahepatic portosystemic shunts in patients with liver cirrhosis.

METHODS

Thirteen patients with an ePTFE-covered transjugular intrahepatic portosystemic shunt stent (TIPSS) were prospectively evaluated at 6 and 12 months and compared with matched controls with mesh-wire uncovered TIPSS.

RESULTS

At 6 months, ePTFE-TIPSS showed a significantly lower porto-caval pressure gradient (PCPG) (9 (3-21) mmHg, P = 0.006), a lower rate of dysfunction (8% versus 54%, P = 0.03) and required fewer reinterventions (2 versus 13, P = 0.02); similar results were obtained after 12 months. This resulted in a reduction in the median cost for angiographic surveillance in the covered TIPSS group at 6 and 12 months (36% and 56% compared to the uncovered TIPSS group, P = 0.002), but total procedure-related costs were higher with the ePTFE-TIPSS (6 months: 3730 (3245-6759) versus 1850 (1466-5479) euro/patient; 12 months: 3945 (3460-6759) versus 2295 (1728-5694) euro/patient) due to the higher initial cost of the ePTFE-covered TIPSS.

CONCLUSIONS

The insertion of ePTFE-covered TIPSS results in better maintenance of lowered portal pressure and fewer reinterventions in patients with liver cirrhosis. There is strong evidence that the use of ePTFE-TIPSS does not require regular surveillance to maintain primary patency, which may then improve cost-effectiveness.

Image quality of noninvasive coronary angiography using multislice spiral computed tomography and electron-beam computed tomography: intraindividual comparison in an animal model

OBJECTIVE

Comparison of coronary artery visualization by multislice spiral CT (MSCT) and electron-beam CT (EBCT).

MATERIALS AND METHODS

Six minipigs underwent MSCT (collimation 4 x 1 mm, gantry rotation time 500 milliseconds, acquisition time per cardiac cycle 126 +/- 30 milliseconds) and EBCT (slice thickness 1.5 mm, acquisition time per scan 100 milliseconds). Visualized vessel length and contour sharpness was measured, contrast-to-noise ratios were calculated, and the frequency of motion artifacts were evaluated.

RESULTS

MSCT depicted significantly longer segments of the coronary tree than EBCT (length: 248.8 vs. 222.8 mm; P < 0.05), delineated the vessel contours more sharply (slope of density curves: 219.2 vs. 160.2 DeltaHU/mm; P < 0.05), and had a higher contrast-to-noise ratio (13.4 vs. 7.3; P < 0.05). The frequency of motion artifacts did not differ between both modalities (94.7% vs. 95.7% of visualized vessel length; P > 0.05).

CONCLUSIONS

Because its higher spatial resolution and lower image noise, MSCT seems to be superior to EBCT in the visualization of the coronary arteries. Despite different temporal resolutions motion artifacts seem to be similar with both modalities.

Comparison of the Iron Oxide-Based Blood-Pool Contrast Medium VSOP-C184 With Gadopentetate Dimeglumine for First-Pass Magnetic Resonance Angiography of the Aorta and Renal Arteries in Pigs

RATIONALE AND OBJECTIVES

VSOP-C184 at a dose of 0.045 mmol Fe/kg has been shown to be an efficient blood pool contrast medium for equilibrium magnetic resonance angiography (MRA) that can be administered as a bolus. The present study was performed to determine whether VSOP-C184 is also suitable for first-pass MRA.

MATERIALS AND METHODS

Fifteen MRA examinations at 1.5 T were performed in minipigs using a fast 3D fast low-angle shot (FLASH) sequence (repetition time = 4.5 ms, echo time = 1.7 ms, excitation angle = 25 degrees, matrix 256, body phased-array coil). The citrate-stabilized iron oxide preparation VSOP-C184 was investigated (total particle diameter: 7.0 +/- 0.15 nm; core size: 4 nm) and compared with gadopentetate dimeglumine (Gd-DTPA). The following doses were tested: VSOP-C184: 0.015, 0.025, and 0.035 mmol Fe/kg; Gd-DTPA: 0.1 and 0.2 mmol Gd/kg; n = 3 examinations/dose. Data were analyzed quantitatively (signal enhancement (ENH) and vessel edge definition (VED)) and qualitatively.

RESULTS

First-pass MRA using the 3 doses of VSOP-C184 yielded the following ENH: aorta: 9.4 +/- 2.6; 12.31 +/- 1.2; 16.53 +/- 1.7; renal arteries: 7.6 +/- 2.2; 9.9 +/- 1.0; 13.2 +/- 0.5. The values for the 2 doses of Gd-DTPA were aorta: 12.9 +/- 1.0; 16.8 +/- 2.2; renal arteries: 11.2 +/- 1.23; 11.3 +/- 1.7. VED for the 3 doses of VSOP-C184 was aorta: 106.3 +/- 31.0; 135.3 +/- 58.8; 141.3 +/- 71.0; renal arteries: 102.2 +/- 24.3; 146.8 +/- 63.0; 126.9 +/- 37.6 and for the 2 doses of Gd-DTPA, aorta: 157.2 +/- 47.8; 164.2 +/- 36.8; renal arteries: 165.9 +/- 30.4; 170.3 +/- 38.2 respectively. The differences between VSOP-C184 and Gd-DTPA are clinically not relevant and statistically not significant (p > or = .05). Qualitative evaluation of image quality, contrast, and delineation of vessels showed the results obtained with VSOP-C184 at doses of 0.025 and 0.035 mmol Fe/kg to be similar to those of Gd-DTPA at 0.1 and 0.2 mmol Gd/kg.

CONCLUSION

VSOP-C184 is suitable for first-pass MRA at doses of 0.025 and 0.035 mmol Fe/kg and thus, in addition to its blood pool characteristics, allows for selective visualization of the arteries without interfering venous signal.

Gadolinium-enhanced three-dimensional magnetic resonance angiography versus conventional digital subtraction angiography: which modality is superior in evaluating living kidney donors?1

This study evaluates the correlation of magnetic resonance angiography (MRA) and digital subtraction angiography (DSA) with the operative vessel findings in living kidney donors. The intraoperative vessel findings of 52 living renal donors were compared with the preoperative diagnoses of each imaging technique. Sixty-seven arteries were found during explantation. Forty kidneys showed a single arterial blood supply, and 12 kidneys showed a multiple arterial blood supply. No advantage of either imaging method was found for arterial imaging. There were 55 veins identified during organ harvesting. MRA could not determine the venous system in one donor (1.9%) and failed to detect one small pole vein in another. DSA did not yield a venous diagnosis in seven patients (13.5%) and yielded misdiagnoses in four patients. The correct diagnosis of renal donor veins differed significantly in favor of MRA (kappa 0.79 vs. 0.45; P=0.008). MRA is superior to DSA in assessing the renal vasculature in living kidney donors.

Disintegration and stepwise expulsion of a large uterine leiomyoma with restoration of the uterine architecture after successful uterine fibroid embolization: case report

Uterine fibroid embolization (UFE) is a new minimally-invasive treatment option for leiomyomata of the uterus leading to symptomatic improvement and shrinkage of the fibroids. We present a case of restoration of the uterine architecture after disintegration and stepwise expulsion of infarcted leiomyoma tissue 7 months after UFE for leiomyoma-related menorrhagia.

Visualization of the pulmonary valve using cine MR imaging

PURPOSE

To evaluate the capability of bright-blood cine MR to directly visualize the leaflets of the valve replacement in pulmonary position following Ross operation.

MATERIAL AND METHODS

Long and short axis views of the pulmonary valve were obtained in 10 normal subjects and 14 patients after Ross operation. Valve morphology and function were analyzed and signal-to-noise (SNR) and contrast-to-noise ratios (CNR) were calculated. Flow measurements were performed in the pulmonary trunk to assess pulmonary regurgitation.

RESULTS

In all subjects, tricuspid morphology of the pulmonary valve was visualized. SNR of the leaflets in normal subjects (9.8 +/- 3.0) and in patients after Ross operation (7.5 +/- 2.2) differed significantly from blood (12.6 +/- 3.2 and 11.3 +/- 2.5, respectively, p < 0.05). Valvular regurgitation was seen in 5 patients as an insufficient closure of the valve which was confirmed by flow measurements.

CONCLUSION

Cine MR enables in-plane visualization of the pulmonary valve and allows for functional and morphological evaluation in patients after pulmonary valve surgery.

Visualization of the pulmonary valve using cine MR imaging

PURPOSE

To evaluate the capability of bright-blood cine MR to directly visualize the leaflets of the valve replacement in pulmonary position following Ross operation.

MATERIAL AND METHODS

Long and short axis views of the pulmonary valve were obtained in 10 normal subjects and 14 patients after Ross operation. Valve morphology and function were analyzed and signal-to-noise (SNR) and contrast-to-noise ratios (CNR) were calculated. Flow measurements were performed in the pulmonary trunk to assess pulmonary regurgitation.

RESULTS

In all subjects, tricuspid morphology of the pulmonary valve was visualized. SNR of the leaflets in normal subjects (9.8 +/- 3.0) and in patients after Ross operation (7.5 +/- 2.2) differed significantly from blood (12.6 +/- 3.2 and 11.3 +/- 2.5, respectively, p < 0.05). Valvular regurgitation was seen in 5 patients as an insufficient closure of the valve which was confirmed by flow measurements.

CONCLUSION

Cine MR enables in-plane visualization of the pulmonary valve and allows for functional and morphological evaluation in patients after pulmonary valve surgery.

[Laparoscopic living donor nephrectomy of kidneys with multiple renal vessels]

Due to the increasing waiting time for transplantation of a cadaveric kidney, living donor kidney transplantation is an increasingly oncoming issue. Laparoscopic donor nephrectomies (LDN) have been performed since 1995 and presently more than 100 transplant centers offer this minimally invasive surgical approach. The advantages for the donor of less pain, shorter hospital stay, earlier return to work, better cosmetic results in combination with an organ function equal to open donor nephrectomy are the reasons for an enormous increase in LDN. Since up to 30% of the donor kidneys have multiple vessels for blood supply, an increase of these organs for LDN can be expected. We performed a retrospective study of LDN at our center and compared donors with multiple vs single vessel supply. From February 1999 to September 2002, 63 LDN were performed at the department of Urology, Charité University Hospital, Berlin. A comparison between 18 donor kidneys with multiple vessel supply and 45 donor organs with single vessels showed no difference for the time of laparoscopic explantation (207 vs 201 min, p=0.4) or the warm (166 vs 148 s, p=0.2) and cold ischemic times (117 vs 103 min, p=0.66). As could be expected, the mixed ischemic time, i.e., the time for anastomosis of the kidney with the recipient's vessels, showed a significant difference (53 vs 46 min, p=0.02). Intra- and postoperative complication rates for donors and recipients were not different in both groups. Laparoscopic donor nephrectomy for kidneys with multiple vessels is feasible and safe for donor and recipient.

Gadobenate dimeglumine-enhanced MR angiography of the abdominal aorta and renal arteries

OBJECTIVE

This study was conducted to determine the efficacy and safety of four different doses of gadobenate dimeglumine for contrast-enhanced three-dimensional MR angiography of the abdominal aorta and renal arteries.

SUBJECTS AND METHODS

Ninety-four patients with suspected abnormality of the abdominal aorta or renal arteries underwent unenhanced three-dimensional gradient-recalled echo time-of-flight MR angiography and contrast-enhanced MR angiography after the IV injection of one of four doses of gadobenate dimeglumine (0.025, 0.05, 0.1, and 0.2 mmol/kg of body weight). Efficacy was assessed on-site and by two blinded off-site reviewers in terms of change in total diagnostic quality score and diagnostic quality score per vessel segment from baseline unenhanced time-of-flight MR angiography to contrast-enhanced MR angiography. Secondary efficacy end points included lesion count and level of confidence in lesion characterization. Safety assessments comprised adverse event monitoring, physical evaluation, vital signs, ECG, and laboratory investigations.

RESULTS

A significant change in the total diagnostic quality score from unenhanced to contrast-enhanced MR angiography was observed at all doses. The change increased with increased dose, plateauing at the 0.1 mmol/kg dose level. More patients with lesions detected and increased reviewer confidence for lesion characterization were noted on contrast-enhanced MR angiography compared with unenhanced MR angiography, although no dose-related trends were observed. All doses were well tolerated, and no significant changes in safety parameters were observed.

CONCLUSION

Gadobenate dimeglumine is an effective and safe agent for contrast-enhanced MR angiography of the abdominal aorta and renal arteries. A dose of 0.1 mmol/kg of body weight appears to be the most suitable.

Three-dimensional gadolinium-enhanced magnetic resonance venography in suspected thrombo-occlusive disease of the central chest veins

STUDY OBJECTIVE

To determine the usefulness of high-resolution three-dimensional (3D) gadolinium-enhanced magnetic resonance venography (MRV) in the evaluation of central venous thrombo-occlusive disease of the chest.

DESIGN

Prospective study.

SETTING

University hospital.

PATIENTS

Sixteen consecutive patients with clinically suspected thrombosis of the superior vena cava, subclavian, brachiocephalic/innominate, internal jugular, or axillary veins. Thirteen patients had a neoplasm, two patients had a connective tissue disease, and one patient had a history of strenuous exercise. Twelve of 16 patients had prior central venous catheter placement. MRI was correlated with color-coded duplex sonography (CCDS) in 7 of 16 patients, digital subtraction angiography (DSA) in 3 of 16 patients, and CT in 2 of 16 patients.

INTERVENTION

Contrast-enhanced MRV was performed in a total of 20 examinations. A 3D data set (gradient echo; time to repeat, 4.6 ms; time to echo, 1.8 ms; flip angle, 30 degrees; time of acquisition, 23 s; 512 matrix/64 partitions; slice thickness, 1.5 mm) was acquired in the arterial and venous phase. Overall image quality was assessed on a 5-point scale. The presence, site, and extent of thrombus, as well as presence of an intravascular device, were determined.

MEASUREMENTS AND RESULTS

Overall image quality was rated very good (1 point) in 7 of 16 cases (44%) and good (2 points) in 9 of 16 cases (56%). Thrombus was detected in 16 of 16 patients, and complete extent of disease could be determined in 15 of 16 patients (94%). MRV did not miss any finding obtained by CCDS, DSA, or CT, and provided additional information in 6 of 16 examinations (38%).

CONCLUSION

Contrast-enhanced MRV is a fast and reliable noninvasive procedure with excellent results regarding detection and determination of the extent of thrombo-occlusive disease of the chest veins.