Cumulative Effective Dose During Fluoroscopically Guided Interventions (FGI): Analysis of More Than 5000 FGIs in a Single European Center

BACKGROUND

The number of fluoroscopically guided interventions (FGI) has increased significantly over time. However, little attention has been paid to possible stochastic radiation effects. The aim of this retrospective study was to investigate the number of patients who received cumulative effective doses over 100 mSv during FGI procedures.

MATERIAL AND METHODS

Five thousand five hundred and fifty four classified FGI procedures were included. Radiation dose data, retrieved from an in-house-dose-management system, was analysed. Effective doses and cumulative effective doses (CED) were calculated. Patients who received a CED > 100 mSv were identified. Radiology reports, patient age, imaging and clinical data of these patients were used to identify reasons for CED ≥ 100 mSv.

RESULTS

One Hundred and thirty two (41.1% female) of 3981 patients received a CED > 100 mSy, with a mean CED of 173.5 ± 84.5 mSv. Mean age at first intervention was 66.1 ± 11.7 years. 81 (61.4%) of 132 were older than 64 years, one patient was < 30 years. 110 patients received ≥ 100 mSv within one year (83.4%), through FGIs: EVAR, pelvic/mesenteric interventions (stent or embolization), hepatic interventions (chemoembolization, TIPSS), embolization of cerebral aneurysms or arterio-venous-malformations.

CONCLUSIONS

Substantial CED may occur in a small but not ignorable fraction of patients (~ 3%) undergoing FGIs. Approximately 2/3rd of patients may most likely not encounter radiation-related stochastic effects due to life-threatening diseases and age at first treatment > 65 years but 1/3rd may. Patients undergoing more than one FGI (77%) carry a higher risk of accumulating effective doses > 100 mSv. Remarkably, 23% received a mean CED 162.2 ± 72.3 mSv in a single procedure.

Radiation dose and diagnostic reference levels for four interventional radiology procedures: results of the prospective European multicenter survey EUCLID

OBJECTIVES

To assess information reflecting radiation dose and define diagnostic reference levels (DRL) on a European basis for four interventional radiology (IR) procedures considering clinical indication, anatomical region, and procedure.

METHODS

A prospective European study was performed to provide data on the IR procedures percutaneous recanalization of iliac arteries, percutaneous recanalization of femoropopliteal arteries, transarterial chemoembolization of hepatocellular carcinoma, and percutaneous transhepatic biliary drainage. Hospitals were asked to complete a questionnaire giving information on procedure, equipment, and protocol. Patient size and weight, experience of the operator graded in number of procedures performed, and complexity level of each procedure were reported. Sixteen hospitals from 13 countries could be surveyed. The percentiles of the kerma-area product, fluoroscopy time, cumulative air kerma at the interventional reference point, and number of images were determined. The impact of equipment, year of installation, and complexity level of the procedure on dose were analyzed.

RESULTS

DRLs based on clinical indication were defined. Dose values varied considerably within hospitals, between them, and within each subgroup of complexity level. The use of state-of-the-art equipment reduced dose significantly by 52%. Although dose also varied within each subgroup of complexity level, for transarterial chemoembolization of hepatocellular carcinoma and percutaneous transhepatic biliary drainage, dose significantly correlated with complexity.

CONCLUSIONS

This was the first study reporting exposure practice and defining DRLs based on clinical indication for four IR procedures on a European basis. These DRLs can serve as a baseline for comparison with local practice, the study as a guideline for future surveys.

KEY POINTS

• The use of state-of-the-art angiographic equipment reduces dose significantly. • A significant correlation between radiation dose and complexity level is found. • Dose values vary considerably, both within and between individual hospitals, and within each complexity level of interventional radiology procedure.

Reciprocal communication of pericoronary adipose tissue and coronary atherogenesis

OBJECTIVE

Pericoronary adipose tissue (PCAT) has been linked to underlying coronary artery disease (CAD) and proposed to modulate adjacent atherosclerotic plaque formation over pro-inflammatory pathways. In vitro and ex vivo studies support the bilateral communication of adipose tissue and vessel wall. We quantified PCAT and its dynamics in a low coronary risk cohort with a semi-automated software in serial coronary computed tomography angiography (CTA).

METHODS

We retrospectively included patients from a tertiary care hospital who underwent serial coronary CTA with a low cardiovascular risk profile. All examinations were evaluated in a standardized approach: epicardial adipose tissue (EAT) volume and attenuation was quantified in total, in the atrioventricular (RCA, LCX) or interventricular (LAD) sulcus and within a 5 mm radius for each coronary artery (PCAT). Coronary plaques were quantified using a semi-automated software and compared for progression, stability or regression.

RESULTS

Of 120 patients (27% females), 59.2% showed atherosclerotic plaques. After 36 months mean follow-up, 22 (18.3%) showed plaque regression, 39 (32.5%) were stable and 49 (40.8%) were progressive. Total EAT volume decreased by -15.6 ± 37.2 mm³ in the regressive group, increased by 2.7 ± 30.6 mm³ in the stable group and by 24.3 ± 37.1 mm³ in the progressive group (p = 0.003). Per-vessel analysis showed a significant decrease of PCAT attenuation in patients with CAD regression (-3.8 ± 7.6HU) compared to the stable (1.2 ± 9.1HU) and progressive group (3.5 ± 8.2HU, p < 0.0001). Mean sulcus EAT attenuation did not show a significant change (p = 0.135).

CONCLUSION

Epicardial adipose tissue volume is mutually changing with the progression or regression of coronary artery disease. Perivascular but not epicardial attenuation levels correlate to adjacent plaque and support a direct bilateral influence.

Albumin-based nanoparticles as contrast medium for MRI: vascular imaging, tissue and cell interactions, and pharmacokinetics of second-generation nanoparticles

This multidisciplinary study examined the pharmacokinetics of nanoparticles based on albumin-DTPA-gadolinium chelates, testing the hypothesis that these nanoparticles create a stronger vessel signal than conventional gadolinium-based contrast agents and exploring if they are safe for clinical use. Nanoparticles based on human serum albumin, bearing gadolinium and designed for use in magnetic resonance imaging, were used to generate magnet resonance images (MRI) of the vascular system in rats ("blood pool imaging"). At the low nanoparticle doses used for radionuclide imaging, nanoparticle-associated metals were cleared from the blood into the liver during the first 4 h after nanoparticle application. At the higher doses required for MRI, the liver became saturated and kidney and spleen acted as additional sinks for the metals, and accounted for most processing of the nanoparticles. The multiple components of the nanoparticles were cleared independently of one another. Albumin was detected in liver, spleen, and kidneys for up to 2 days after intravenous injection. Gadolinium was retained in the liver, kidneys, and spleen in significant concentrations for much longer. Gadolinium was present as significant fractions of initial dose for longer than 2 weeks after application, and gadolinium clearance was only complete after 6 weeks. Our analysis could not account quantitatively for the full dose of gadolinium that was applied, but numerous organs were found to contain gadolinium in the collagen of their connective tissues. Multiple lines of evidence indicated intracellular processing opening the DTPA chelates and leading to gadolinium long-term storage, in particular inside lysosomes. Turnover of the stored gadolinium was found to occur in soluble form in the kidneys, the liver, and the colon for up to 3 weeks after application. Gadolinium overload poses a significant hazard due to the high toxicity of free gadolinium ions. We discuss the relevance of our findings to gadolinium-deposition diseases.

Performance of different Dixon-based methods for MR liver iron assessment in comparison to a biopsy-validated R2* relaxometry method

Objectives

To prospectively evaluate a 3D-multiecho-Dixon sequence with inline calculation of proton density fat fraction (PDFF) and R2* (qDixon), and an improved version of it (qDixon-WIP), for the MR-quantification of hepatic iron in a clinical setting.

Methods

Patients with increased serum ferritin underwent 1.5-T MRI of the liver for the evaluation of hepatic iron overload. The imaging protocol for R2* quantification included as follows: (1) a validated, 2D multigradient-echo sequence (initial TE 0.99 ms, R2*-ME-GRE), (2) a 3D-multiecho-Dixon sequence with inline calculation of PDFF and R2* (initial TE 2.38 ms, R2*-qDixon), and optionally (3) a prototype (works-in-progress, WIP) version of the latter (initial TE 1.04 ms, R2*-qDixon-WIP) with improved water/fat separation and noise-corrected parameter fitting. For all sequences, three manually co-registered regions of interest (ROIs) were placed in the liver. R2* values were compared and linear regression analysis and Bland-Altman plots calculated.

Results

Forty-six out of 415 patients showed fat-water (F/W) swap with qDixon and were excluded. A total of 369 patients (mean age 52 years) were included; in 203/369, the optional qDixon-WIP was acquired, which showed no F/W swaps. A strong correlation was found between R2*-ME-GRE and R2*-qDixon (r² = 0.92, p < 0.001) with Bland-Altman revealing a mean difference of − 3.82 1/s (SD = 21.26 1/s). Correlation between R2*-GRE-ME and R2*-qDixon-WIP was r² = 0.95 (p < 0.001) with Bland-Altman showing a mean difference of − 0.125 1/s (SD = 30.667 1/s).

Conclusions

The 3D-multiecho-Dixon sequence is a reliable tool to quantify hepatic iron. Results are comparable with established relaxometry methods. Improvements to the original implementation eliminate occasional F/W swaps and limitations regarding maximum R2* values.

Key Points

• The 3D-multiecho-Dixon sequence for 1.5 T is a reliable tool to quantify hepatic iron.

• Results of the 3D-multiecho-Dixon sequence are comparable with established relaxometry methods.

• An improved version of the 3D-multiecho-Dixon sequence eliminates minor drawbacks.

Diagnostic Reference Levels based on clinical indications in computed tomography: a literature review

BACKGROUND

In August 2017, the European Commission awarded the "European Study on Clinical Diagnostic Reference levels for X-ray Medical Imaging" project to the European Society of Radiology, to provide up-to-date Diagnostic Reference Levels based on clinical indications. The aim of this work was to conduct an extensive literature review by analysing the most recent studies published and the data provided by the National Competent Authorities, to understand the current situation regarding Diagnostic Reference Levels based on clinical indications for computed tomography.

RESULTS

The literature review has identified 23 papers with Diagnostic Reference Levels based on clinical indications for computed tomography from 15 countries; 12 of them from Europe. A total of 28 clinical indications for 6 anatomical areas (head, cervical spine/neck, chest, abdomen, abdomen-pelvis, chest-abdomen-pelvis) have been identified.

CONCLUSIONS

In all the six anatomical areas for which Diagnostic Reference Levels based on clinical indications were found, a huge variation of computed tomography dose descriptor values was identified, providing evidence for a need to develop strategies to standardise and optimise computed tomography protocols.

Unintended and Accidental Exposures, Significant Dose Events and Trigger Levels in Interventional Radiology

Over recent years, an increasing number of fluoroscopically guided interventions (FGIs) have been performed by radiologists and non-radiologists. Also, the number of complex interventional procedures has increased. In the late nineties, first reports of skin injuries appeared in the literature. The medical community responded through increased awareness for radiation protection and public authorities by recommendations and legislation, for example, the European Basic Safety Standards (EU-BSS) which were published in 2014, or the international Basic Safety Standards (BSS). Implementation of the EU-BSS requires concerted action from interventionalists, radiographers, medical physics experts and competent national authorities. Interventionalists should play an important role in this project since implementation of the EU-BSS will affect their daily practice. This paper discusses some important issues of the EU-BSS such as unintended and accidental radiation exposures of patients, the meaning of significant dose events and how to deal with patients who were exposed to a substantial radiation dose with the risk of tissue injuries. In addition, this paper provides practical advice on how to implement alert and trigger levels in daily practice of FGIs in order to increase patient safety.

Dual-Energy Computed Tomography Detection of Cardiovascular Monosodium Urate Deposits in Patients With Gout

Importance

The prevalence of gout has increased in recent decades. Several clinical studies have demonstrated an association between gout and coronary heart disease, but direct cardiovascular imaging of monosodium urate (MSU) deposits by using dual-energy computed tomography (DECT) has not been reported to date.

Objective

To compare coronary calcium score and cardiovascular MSU deposits detected by DECT in patients with gout and controls.

Design, Setting, and Participants

This prospective Health Insurance Portability and Accountability Act-compliant study included patients with gout and controls who presented to a rheumatologic clinic from January 1, 2017, to November 1, 2018. All consecutive patients underwent DECT to assess coronary calcium score and MSU deposits in aorta and coronary arteries. In addition, cadavers were assessed by DECT for cardiovascular MSU deposits and verified by polarizing microscope. Analysis began in January 2017.

Main Outcomes and Measures

Detection rate of cardiovascular MSU deposits using DECT in patients with gout and control group patients without a previous history of gout or inflammatory rheumatic diseases.

Results

A total of 59 patients with gout (mean [SD] age, 59 [5.7] years; range, 47-89 years), 47 controls (mean [SD] age, 70 [10.4] years; range, 44-86 years), and 6 cadavers (mean [SD] age at death, 76 [17] years; range, 56-95 years) were analyzed. The frequency of cardiovascular MSU deposits was higher among patients with gout (51 [86.4%]) compared with controls (7 [14.9%]) (χ2 = 17.68, P < .001), as well as coronary MSU deposits among patients with gout (19 [32.2%]) vs controls (2 [4.3%]) (χ2 = 8.97, P = .003). Coronary calcium score was significantly higher among patients with gout (900 Agatston units [AU]; 95% CI, 589-1211) compared with controls (263 AU; 95% CI, 76-451; P = .001) and also significantly higher among 58 individuals with cardiovascular MSU deposits (950 AU; 95% CI, 639-1261) compared with 48 individuals without MSU deposits (217 AU; 95% CI, 37-397; P < .001). Among 6 cadavers, 3 showed cardiovascular MSU deposits, which were verified by polarizing light microscope.

Conclusion and Relevance

Dual-energy computed tomography demonstrates cardiovascular MSU deposits, as confirmed by polarized light microscopy. Cardiovascular MSU deposits were detected by DECT significantly more often in patients with gout compared with controls and were associated with higher coronary calcium score. This new modality may be of importance in gout population being at risk from cardiovascular disease.

Magnetic resonance cholangiopancreatography with compressed sensing at 1.5 T: clinical application for the evaluation of branch duct IPMN of the pancreas

Objectives

To evaluate magnetic resonance cholangiopancreatography (MRCP) with compressed sensing (CS) for the assessment of branch duct intraductal papillary mucinous neoplasm (BD-IPMN) of the pancreas. For this purpose, conventional navigator-triggered (NT) sampling perfection with application-optimized contrast using different flip angle evolutions (SPACE) MRCP was compared with various CS-SPACE-MRCP sequences in a clinical setting.

Methods

A total of 41 patients (14 male, 27 female, mean age 68 years) underwent 1.5-T MRCP for the evaluation of BD-IPMN. The MRCP protocol consisted of the following sequences: conventional NT-SPACE-MRCP, CS-SPACE-MRCP with long (BHL, 17 s) and short single breath-hold (BHS, 8 s), and NT-CS-SPACE-MRCP. Two board-certified radiologists evaluated image quality, duct sharpness, duct visualization, lesion conspicuity, confidence, and communication with the main pancreatic duct in consensus using a 5-point scale (1–5), with higher scores indicating better quality/delineation/confidence. Maximum intensity projection reconstructions and originally acquired data were used for evaluation. Wilcoxon signed-rank test was used to compare the intra-individual difference between sequences.

Results

BHS-CS-SPACE-MRCP had the highest scores for image quality (3.85 ± 0.79), duct sharpness (3.81 ± 1.05), and duct visualization (3.81 ± 1.01). There was a significant difference compared with NT-CS-SPACE-MRCP (p < 0.05) but no significant difference to the standard NT-SPACE-MRCP (p > 0.05). Concerning diagnostic quality, BHS-CS-SPACE-MRCP had the highest scores in lesion conspicuity (3.95 ± 0.92), confidence (4.12 ± 1.08), and communication (3.8 ± 1.06), significantly higher compared with NT-SPACE-MRCP, BHL-SPACE-MRCP, and NT-CS-SPACE-MRCP (p = <0.05).

Conclusions

MRCP with CS 3D SPACE for the evaluation of BD-IPMN at 1.5 T provides the best results using a short breath-hold sequence. This approach is feasible and an excellent alternative to standard NT 3D MRCP sequences.

Key Points

• 1.5-T MRCP with compressed sensing for the evaluation of branch duct IPMN is a feasible method.

• Short breath-hold sequences provide the best results for this purpose.

MITIGATE-NeoBOMB1, a Phase I/IIa Study to Evaluate Safety, Pharmacokinetics, and Preliminary Imaging of 68Ga-NeoBOMB1, a Gastrin-Releasing Peptide Receptor Antagonist, in GIST Patients

Gastrin-releasing peptide receptors (GRPRs) are potential molecular imaging targets in a variety of tumors. Recently, a ⁶⁸Ga-labeled antagonist to GRPRs, NeoBOMB1, was developed for PET. We report on the outcome of a phase I/IIa clinical trial (EudraCT 2016-002053-38) within the EU-FP7 project Closed-loop Molecular Environment for Minimally Invasive Treatment of Patients with Metastatic Gastrointestinal Stromal Tumors ('MITIGATE') (grant agreement no. 602306) in patients with oligometastatic gastrointestinal stromal tumors (GIST). Methods: The main objectives were evaluation of safety, biodistribution, dosimetry, and preliminary tumor targeting of ⁶⁸Ga-NeoBOMB1 in patients with advanced tyrosine-kinase inhibitors-treated GIST using PET/CT. Six patients with histologically confirmed GIST and unresectable primary lesion or metastases undergoing an extended protocol for detailed pharmacokinetic analysis were included. ⁶⁸Ga-NeoBOMB1 was prepared using a kit procedure with a licensed ⁶⁸Ge/⁶⁸Ga generator. ⁶⁸Ga-NeoBOMB1 (3 MBq/kg of body weight) was injected intravenously, and safety parameters were assessed. PET/CT included dynamic imaging at 5, 11, and 19 min as well as static imaging at 1, 2, and 3-4 h after injection for dosimetry calculations. Venous blood samples and urine were collected for pharmacokinetic analysis. Tumor targeting was assessed on a per-lesion and per-patient basis. Results: ⁶⁸Ga-NeoBOMB1 (50 μg) was prepared with high radiochemical purity (yield > 97%). Patients received 174 ± 28 MBq of the radiotracer, which was well tolerated in all patients over a follow-up period of 4 wk. Dosimetry calculations revealed a mean effective dose of 0.029 ± 0.06 mSv/MBq, with the highest organ dose to the pancreas (0.274 ± 0.099 mSv/MBq). Mean plasma half-life was 27.3 min with primarily renal clearance (mean 25.7% ± 5.4% of injected dose 4 h after injection). Plasma metabolite analyses revealed high stability; metabolites were detected only in the urine. In 3 patients, a significant uptake with increasing maximum SUVs (SUV_max at 2 h after injection: 4.3-25.9) over time was found in tumor lesions. Conclusion: This phase I/IIa study provides safety data for ⁶⁸Ga-NeoBOMB1, a promising radiopharmaceutical for targeting GRPR-expressing tumors. Safety profiles and pharmacokinetics are suitable for PET imaging, and absorbed dose estimates are comparable to those of other ⁶⁸Ga-labeled radiopharmaceuticals used in clinical routine.

Non-contrast MRI protocol for TAVI guidance: quiescent-interval single-shot angiography in comparison with contrast-enhanced CT

Objectives

To prospectively compare unenhanced quiescent-interval single-shot MR angiography (QISS-MRA) with contrast-enhanced computed tomography angiography (CTA) for contrast-free guidance in transcatheter aortic valve intervention (TAVI).

Methods

Twenty-six patients (mean age 83 ± 5 years, 15 female [58%]) referred for TAVI evaluation underwent QISS-MRA for aortoiliofemoral access guidance and non-contrast three-dimensional (3D) “whole heart” MRI for prosthesis sizing on a 1.5-T system. Contrast-enhanced CTA was performed as imaging gold standard for TAVI planning. Image quality was assessed by a 4-point Likert scale; continuous MRA and CTA measurements were compared with regression and Bland-Altman analyses.

Results

QISS-MRA and CTA-based measurements of aortoiliofemoral vessel diameters correlated moderately to very strong (r = 0.572 to 0.851, all p ≤ 0.002) with good to excellent inter-observer reliability (intra-class correlation coefficient (ICC) = 0.862 to 0.999, all p < 0.0001) regarding QISS assessment. Mean diameters of the infrarenal aorta and iliofemoral vessels differed significantly (bias 0.37 to 0.98 mm, p = 0.041 to < 0.0001) between the two modalities. However, inter-method decision for transfemoral access route was comparable (κ = 0.866, p < 0.0001). Aortic root parameters assessed by 3D whole heart MRI strongly correlated (r = 0.679 to 0.887, all p ≤ 0.0001) to CTA measurements.

Conclusion

QISS-MRA provides contrast-free access route evaluation in TAVI patients with moderate to strong correlations compared with CTA and substantial inter-observer agreement. Despite some significant differences in minimal vessel diameters, inter-method agreement for transfemoral accessibility is strong. Combination with 3D whole heart MRI facilitates unenhanced TAVI guidance.

Key Points

• QISS-MRA and CTA inter-method agreement for transfemoral approach is strong.

• QISS-MRA is a very good alternative to CTA and MRA especially in patients with Kidney Disease Outcomes Quality Initiativestages 4 and 5.

• Combination of QISS-MRA and 3D “whole heart” MRI facilitates fully unenhanced TAVI guidance.

Enlarged cardiophrenic lymph nodes predict disease involvement of the upper abdomen and the outcome of primary surgical debulking in advanced ovarian cancer

INTRODUCTION

The outcome of ovarian cancer patients is highly dependent on the success of primary debulking surgery in terms of postoperative residual disease. This study critically evaluates the clinical impact of preoperative radiologic assessment of the cardiophrenic lymph node (CPLN) status in advanced ovarian cancer.

MATERIAL AND METHODS

Baseline CT scans of 178 stage III and IV ovarian cancer patients were retrospectively reviewed by two independent radiologists. CPLN enlargement defined at a short-axis ≥5 mm was evaluated for its prognostic value and predictive power of upper abdominal tumor involvement and the chance of complete intra-abdominal tumor resection at primary debulking surgery. Only patients without surgically removed CPLN were eligible for this study.

RESULTS

Enlarged CPLNs were detected in 50% of patients and correlated with radiologically suspicious (P = .028) and histologically confirmed (P = .001) paraaortic lymph node metastases. CPLNs ≥ 5 mm were associated with high CA-125 levels at baseline and revealed independent prognostic relevance for progression-free survival (hazard ratio [HR] 2.14, 95% confidence interval [CI] 1.33-3.42) and overall survival (HR 2.18, 95% CI 1.16-4.08). Noteworthy, patients with enlarged CPLNs nonetheless benefit from complete intra-abdominal tumor debulking in terms of an improvement in progression-free survival (HR 0.60, 95% CI 0.38-0.94) and overall survival (HR 0.59, 95% CI 0.35-0.82). Enlarged CPLNs correctly predicted carcinomatosis of the upper abdomen in 94.6%. A predictive score of complete tumor debulking, termed CD-score, which integrates, beside a CPLN short axis <5 mm, an ascites volume <500 mL, and CA-125 levels <500 U/mL at baseline, correctly predicted complete intra-abdominal debulking in 100% of patients.

CONCLUSIONS

CPLNs ≥5 mm predict upper abdominal tumor involvement. The application of the CD-score predicted complete macroscopic tumor resection at primary surgery in all of the patients. Although, CPLN pathology suggests extra-abdominal disease, we consistently demonstrated that patients nonetheless benefit from complete intra-abdominal tumor resection.

NEN: Advancement in Diagnosis and Minimally Invasive Therapy

Neuroendocrine neoplasms (NEN) are a heterogeneous type of malignant disease and frequently present with symptoms caused by the secretion of metabolically active substances or the manifestation of distant metastases, with the liver being the most frequent site of spreading. Early diagnosis of metastatic disease is recognized as the major prognostic factor in NEN patients. Complete surgical resection is feasible in only selected cases. For patients with unresectable liver metastases, various locoregional treatment approaches are available. Over the last decade, therapeutic procedures including locoregional and systemic treatments have been investigated for gastroenteropancreatic NEN (GEP-NEN), especially for metastatic disease to the liver. Only a few prospective clinical trials have compared these approaches, and the management of individual patients remains subject to clinical expertise and judgement. Locoregional treatments are applicable in patients with limited metastatic involvement of the liver, and may be used for tumor debulking and symptom control in patients with diffuse liver involvement. KEY POINTS:: · Neuroendocrine Neoplasms (NENs) represent a heterogeneous class of rare malignancies.. · Surgery is the treatment of choice for primary non-metastatic NEN.. · The liver is the most frequently affected site by neuroendocrine metastases.. · In limited metastastic liver disease local curative treatment may be accomplished by surgical resection or percutaneous thermal ablation.. · Multi-probe stereotactic thermal ablation with image fusion for intraoperative evaluation of a sufficient safety margin allows for safe and effective treatment of large liver metastases.. CITATION FORMAT: · Putzer D, Schullian P, Jaschke W et al. NET: Neue Entwicklungen in Diagnostik und minimalinvasiver Therapie. Fortschr Röntgenstr 2020; 192: 422 - 430.

Chronic gastric ulcer disease complicating selective internal radiation therapy (SIRT) in a patient with cholangiocellular carcinoma

Selective internal radiation therapy (SIRT) is a therapeutic option for primary and metastatic liver tumors. Microspheres containing Yttrium 90, a beta-emitting radionuclide, are administered into the hepatic artery allowing selective internal radiation of a liver tumor. SIRT-related complications may appear due to migration of the radiation microspheres to organs distant from the tumor site. In order to prevent these complications, unintended non target embolization of Yttrium microspheres has to be avoided. However, data from external-beam radiation therapy (EBRT) suggests that the stomach/small bowel may actually be less radiosensitive than the liver. Gastric ulcers, a well-known SIRT-related complication, may therefore not only be caused by local radiation but also by unusual accumulation of microspheres in the submucosa and small vessel damage. We herein report a more than two- year-long persisting, highly symptomatic, non-neoplastic ulceration of the gastric antrum leading to pyloric stenosis caused by SIRT therapy with Yttrium 90 microspheres for the treatment of intrahepatic cholangiocellular carcinoma. The chronic courses of the ulcer disease together with the specific histological features highlight the pivotal role of radiation-induced small vessel damage in SIRT-induced adverse events.

[Adverse effects of immunotherapy : Clinical aspects, radiological and nuclear medicine results]

BACKGROUND

The increasing use of immunotherapy in oncology increases the need for radiologic evaluation of frequent and severe immune-related adverse events.

OBJECTIVE

Determination of the incidence and manifestation of radiologic and nuclear medicine findings of immune-related adverse events.

MATERIAL AND METHODS

Literature review of clinical and imaging findings of immune-related adverse events induced by the immune checkpoint inhibitors ipilimumab, nivolumab and pembrolizumab. Findings are illustrated with pictorial examples and contrasted to other relevant differential diagnoses.

RESULTS

The most frequent imaging manifestations are colitis, hepatitis, pancreatitis, hypophysitis, pneumonitis, arthritis and sarcoid-like lymphadenopathy. Severe to life-threatening complications may result from colitis, pneumonitis and hypophysitis. A clear differentiation from other autoimmune diseases and discrimination of immune-related and infectious pulmonary findings can be very difficult and need close multidisciplinary collaboration.

CONCLUSION

Knowledge of clinical and imaging findings of adverse events induced by immunotherapy is essential for timely and adequate therapeutic decisions. In addition to staging and follow-up imaging, identification and monitoring of immune-related adverse events adds to the radiologic responsibility in oncologic care.

Fusion Imaging of Contrast-enhanced Ultrasound With CT or MRI for Kidney Lesions

AIM

To evaluate the feasibility of ultrasound (US) computed tomography (CT) or magnetic resonance imaging (MRI) fusion imaging (FI) for localization and assessment of kidney lesions.

MATERIALS AND METHODS

Twenty-eight patients with kidney lesions previously detected on CT or MRI were included in this retrospective study. All 28 patients with kidney lesions, which were indefinable (42.9%) or hard to localize (57.1%) on gray-scale US alone, underwent FI of US with CT/MRI datasets. In 23 (82%) patients with indeterminate kidney lesions, FI including contrast-enhanced US was conducted.

RESULTS

FI was successfully performed in 25 out of 28 (89.3%) patients. FI with contrast-enhanced US was able to clarify the previously detected kidney lesions in 21 out of 23 patients (91.3%).

CONCLUSION

FI is a feasible technique for localizing kidney lesions that are hard to define by grayscale US alone and the additional application of contrast-enhanced US is useful in clarifying indeterminate CT or MRI findings.

Does gadoxetate disodium affect MRE measurements in the delayed hepatobiliary phase?

OBJECTIVES

To assess if the administration of gadoxetate disodium (Gd-EOB-DTPA) significantly affects hepatic magnetic resonance elastography (MRE) measurements in the delayed hepatobiliary phase (DHBP).

METHODS

A total of 47 patients (15 females, 32 males; age range 23-78 years, mean 54.28 years) were assigned to standard hepatic magnetic resonance imaging (MRI) with application of Gd-EOB-DTPA and hepatic MRE. MRE was performed before injection of Gd-EOB-DTPA and after 40-50 min in the DHBP. Liver stiffness values were obtained before and after contrast media application and differences between pre- and post-Gd-EOB-DTPA values were evaluated using a Bland-Altman plot and the Mann-Whitney-Wilcoxon test. In addition, the data were compared with regard to the resulting fibrosis classification.

RESULTS

Mean hepatic stiffness for pre-Gd-EOB-DTPA measurements was 4.01 kPa and post-Gd-EOB-DTPA measurements yielded 3.95 kPa. We found a highly significant individual correlation between pre- and post-Gd-EOB-DTPA stiffness values (Pearson correlation coefficient of r = 0.95 (p < 0.001) with no significant difference between the two measurements (p =0.49)). Bland-Altman plot did not show a systematic effect for the difference between pre- and post-stiffness measurements (mean difference: 0.06 kPa, SD 0.81). Regarding the classification of fibrosis stages, the overall agreement was 87.23% and the intraclass correlation coefficient was 96.4%, indicating excellent agreement.

CONCLUSIONS

Administration of Gd-EOB-DTPA does not significantly influence MRE stiffness measurements of the liver in the DHBP. Therefore, MRE can be performed in the DHBP.

KEY POINTS

• MRE of the liver can reliably be performed in the delayed hepatobiliary phase. • Gd-EOB-DTPA does not significantly influence MRE stiffness measurements of the liver. • MRE performed in the delayed hepatobiliary-phase is reasonable in patients with reduced liver function.

Monitoring Iron Overload: Relationship between R2* Relaxometry of the Liver and Serum Ferritin under Different Therapies

Objective:

The objective of this study was to evaluate the relationship between hepatic magnetic resonance imaging (MRI) with R2* relaxometry and serum ferritin in therapy monitoring of patients with iron overload. Further, a possible influence of the chosen therapy (phlebotomy or chelation) was assessed.

Materials and Methods:

We retrospectively evaluated 42 patients with baseline and follow-up R2* relaxometry and determination of serum ferritin before and during therapeutic phlebotomy or iron chelation therapy or watchful waiting, respectively. Linear regression analysis was used to analyze the correlation between changes of R2* and serum ferritin. Regression lines for different groups were compared with analysis of covariance.

Results:

We found a moderate positive statistical correlation (r = 0.509) between serum ferritin and R2*, a moderate positive correlation between absolute R2* changes and serum ferritin changes (r = 0.497), and a strong correlation for percentage changes (r = 0.712). The correlation analysis between relative changes of R2* and serum ferritin for the different therapies resulted in a strong correlation between phlebotomy and chelation (r = 0.855/0.727) and a moderate for no applied therapy (r = 0.536). In 22/92 paired examinations, a discordance of R2* and ferritin was found, particularly involving patients under chelation.

Conclusions:

Despite the good correlation between serum ferritin and R2* relaxometry in monitoring iron overload, treatment response may be misinterpreted when only serum ferritin is considered. Although ferritin is an acceptable and far cheaper tool for monitoring, MRI should be performed for confirmation, especially in case of unexpected ferritin changes, particularly under chelation therapy.

Gout of hand and wrist: the value of US as compared with DECT

Objectives

The purpose of this study was to compare findings of ultrasound (US) with dual-energy CT (DECT) in patients presenting with suspected gouty hand and wrist arthritis.

Methods

This prospective study included 180 patients (136 men and 44 women, age range, 31– 94 years; mean age, 65.9 years) with an initial clinical diagnosis of acute gouty arthritis who underwent DECT and US examination. Intra- and extra-articular findings of each modality were tabulated and calculated with DECT as gold standard.

Results

The final diagnosis of gout was positive in 97/180 patients (53.9%) by DECT, an alternative diagnosis confirmed in 83 patients. US showed a sensitivity of 70.1% (extra-articular: 42.5%, p < 0.0001; intra-articular: 80.3%, p = 0.14) and specificity of 51%. The double contour sign (DCS) was present in 58/61 patients with a positive US study for intra-articular gout (95.1%).

Conclusions

Sensitivity of US for diagnosis of gouty arthritis in hand and wrist is limited, particularly with respect to extra-articular urate deposition. The DCS is the most sensitive sign for the assessment of gouty hand and wrist arthritis by US.

Key points

• Sensitivity of US for diagnosis of gouty arthritis in hand and wrist is limited, particularly with respect to extra-articular gouty deposits.

• The double contour sign is the most sensitive finding for the assessment of gouty hand and wrist arthritis by US.

• Although the sensitivity of US for diagnosis of gouty hand and wrist arthritis is limited, it can be used as a first-line imaging modality in the presence of the DCS.

Integrating interventional oncology in the treatment of liver tumors

Background

Percutaneous ablation techniques offer a vast armamentarium for local, minimally invasive treatment of liver tumors, nowadays representing an established therapeutic option, which is integrated in treatment algorithms, especially for non-resectable liver tumors. The results of ablative treatment compare very well to surgical treatment in liver lesions, and confirm that these techniques are a valuable option for bridging for transplantation. Different techniques have been established to perform tumor ablation, and the feasibility varies according to the procedure and technical skills of the operator, depending on the size and location of the liver lesion. In recent years, stereotactic multi-needle techniques using 3D trajectory planning, general anesthesia, and tube disconnection during needle placement have had a strong impact on the application range of ablation for liver tumors.

Conclusion

It is well known that creating a sufficient ablation margin and overlapping ablation zones is one key issue to enable ablation of large liver lesions with tumor-free margins (A0 ablation in analogy to R0 resection). Image fusion during treatment and follow-up assure highly accurate staging procedures and interventional planning.

Novel aspects

Review on the standards in ablation techniques for the treatment of liver tumors. Update on different ablation techniques, indications, and contraindications for percutaneous liver tumor treatment. Summary of recently published reports on liver tumor ablation.

Imaging Features of Toxicities by Immune Checkpoint Inhibitors in Cancer Therapy

Purpose of review

With the increasing use of immune checkpoint inhibitors in cancer therapy radiographic profiling of frequent and serious immune-related adverse events (irAEs) becomes more relevant. This article reviews imaging features of irAEs induced by the anti-CTLA-4 and anti-PD-1 antibodies ipilimumab, nivolumab and pembrolizumab.

Recent findings

Important radiological manifestations are immune-related colitis, hepatitis, pancreatitis, hypophysitis, pneumonitis, arthritis and sarcoid-like lymphadenopathy. Typical imaging features are summarized and compared with other relevant differential diagnoses.

Summary

Early diagnosis and appropriate therapeutic decisions are required for a successful treatment of irAEs. In addition to staging and follow-up imaging, identification and monitoring of adverse events becomes an important radiologic aspect in oncologic care.

Prognostic factors in endovascular treated pelvic haemorrhage after blunt trauma

Background

Angioembolization is the method of choice for treating haemorrhage after blunt pelvic trauma. The aim of this study was to determine technical factors related to endovascular procedures which might be related to patient outcome.

Methods

This retrospective study included 112 consecutive patients (40 women and 72 men; mean age 57.2 ± 20.0).

Results

There were age peaks at 43 and at 77 years. Patients over 65 years had mainly “low-energy” trauma; younger patients were more likely to have polytraumas. Younger patients were more severely injured and had more surgical interventions, larger haematoma volumes, lower Hb levels and required more transfusions than older patients. Women were older than men, had fewer surgeries and waited longer for an angiography (p < 0.05 each). Logistic regression analyses identified the injury severity score (ISS) as relevant for survival before age, haematoma volume and Hb. Propensity score analyses showed that in addition to the need for transfusions, haemoglobin, and haematoma volume, the length of the coils and the number of microcoils used were relevant (p < 0.05 each). The location of haemorrhage in peripheral parietal arteries (superior and inferior gluteal artery) was an influencing factor for re-angiographies, which were associated with considerably longer hospital stays of more than 40 days. Fewer particles had generally been used in these patients.

Conclusions

The use of too few coils and not using microparticles in angioembolization for pelvic haemorrhage are major influencing factors for the mortality or re-angiography rate. Special attention should be given to thorough peripheral embolization with microcoils, in particular for haemorrhage from the parietal branches of the internal iliac artery.

Value of Multiparametric US in the Assessment of Intratesticular Lesions

Purpose To evaluate the diagnostic accuracy of multiparametric ultrasonography (US) consisting of gray-scale US, color Doppler US, strain elastography, and contrast agent-enhanced US in the assessment of intratesticular lesions. Materials and Methods Institutional review board approval was obtained for this retrospective study. From January 2012 to December 2015, 55 focal testicular lesions that were indeterminate on gray-scale US scans were further characterized with color Doppler US, strain elastography, and contrast-enhanced US. Strain elastography was performed to assess tissue elasticity, and hard lesions were defined as malignant. Color Doppler US and contrast-enhanced US were performed to determine the absence or presence of vascularization. Avascular lesions were defined as benign. Histopathologic results or follow-up examinations served as reference standards. Correct classification rate, sensitivity, specificity, and likelihood ratio were calculated. Results Of 55 testicular lesions, 43 (78.2%) were benign and 12 (21.8%) were malignant. Single-modality sensitivities and specificities were 66.7% and 88.4% for color Doppler US, 100% and 76.7% for contrast-enhanced US, and 100% and 72.1% for strain elastography, respectively. Among 12 malignant lesions, color Doppler US failed to demonstrate vascularization in four (33.3%) lesions, which were positive for cancer at contrast-enhanced US. By combining strain elastography and contrast-enhanced US, a sensitivity of 100% and specificity of 93.0% were achieved in differentiating benign and malignant focal testicular lesions. Positive likelihood ratio was 5.7 for color Doppler US, 4.3 for contrast-enhanced US, 3.6 for strain elastography, 14.3 for strain elastography combined with color Doppler US, and 14.3 for strain elastography combined with contrast-enhanced US. Conclusion Multiparametric US allows for a reliable differentiation of benign and malignant intratesticular lesions and can potentially be useful in deciding whether orchiectomy can be replaced with follow-up or less invasive organ-sparing strategies. ^© RSNA, 2017.

Radiation-Induced Skin Injuries to Patients: What the Interventional Radiologist Needs to Know

For a long time, radiation-induced skin injuries were only encountered in patients undergoing radiation therapy. In diagnostic radiology, radiation exposures of patients causing skin injuries were extremely rare. The introduction of fast multislice CT scanners and fluoroscopically guided interventions (FGI) changed the situation. Both methods carry the risk of excessive high doses to the skin of patients resulting in skin injuries. In the early nineties, several reports of epilation and skin injuries following CT brain perfusion studies were published. During the same time, several papers reported skin injuries following FGI, especially after percutaneous coronary interventions and neuroembolisations. Thus, CT and FGI are of major concern regarding radiation safety since both methods can apply doses to patients exceeding 5 Gy (National Council on Radiation Protection and Measurements threshold for substantial radiation dose level). This paper reviews the problem of skin injuries observed after FGI. Also, some practical advices are given how to effectively avoid skin injuries. In addition, guidelines are discussed how to deal with patients who were exposed to a potentially dangerous radiation skin dose during medically justified interventional procedures.

3D Multiecho Dixon for the Evaluation of Hepatic Iron and Fat in a Clinical Setting

PURPOSE

To prospectively evaluate a new 3D-multiecho-Dixon (3D-ME-Dixon) sequence for the quantification of hepatic iron and fat in a clinical setting.

MATERIALS AND METHODS

In all, 120 patients underwent 1.5T magnetic resonance imaging of the liver between December 2013 and June 2015 including the following three sequences: 3D-ME-Dixon with inline calculation of R2* and proton-density fat-fraction (PDFF) maps, single-voxel-spectroscopy (SVS), 2D multigradient-echo sequence (2D-ME-GRE). SVS and 2D-ME-GRE were used as reference for PDFF and R2*, respectively. R2*- and PDFF-values from 3D-ME-Dixon were compared with those of the reference. Linear regression analysis, Bland-Altman plots, and agreement parameters were calculated.

RESULTS

In total, 103 patients were finally included (87 men and 16 women; mean age, 50.51 years); 17/120 were excluded due to fat/water-swaps or R2*-values exceeding the constraint of 400 1/s for 3D-ME-Dixon. A strong correlation (r = 0.992, P < 0.001) between R2* of 3D-ME-Dixon and the reference 2D-ME-GRE was found. Bland-Altman analysis revealed systematically lower values for 3D-ME-Dixon (16.499%). Using an adapted threshold of 57 1/s, 3D-ME-Dixon obtained a positive/negative percentage agreement (PPA/NPA) of 84.4%/91.4% for detecting hepatic iron overload. For hepatic fat the correlation between 3D-ME-Dixon and the reference SVS was strong (r = 0.957, P < 0.001); PPA/NPA was 88.3%/91.4%.

CONCLUSION

The 3D-ME-Dixon sequence is a valuable tool for the evaluation of hepatic iron and fat in a clinical setting. Fat/water-swaps remain a drawback requiring improvements to the implementation and making it necessary to have proven conventional sequences at hand in case of an eventual occurrence.

LEVEL OF EVIDENCE

1. Technical Efficacy: Stage 2 J. MAGN. RESON. IMAGING 2017;46:793-800.

R2*-relaxometry of the pancreas in patients with human hemochromatosis protein associated hereditary hemochromatosis

PURPOSE

To evaluate pancreatic iron in patients with human hemochromatosis protein associated hereditary hemochromatosis (HHC) using R2* relaxometry.

MATERIALS AND METHODS

81 patients (58 male, 23 female; median age 49.5, range 10-81 years) with HHC were retrospectively studied. All underwent 1.5T magnetic resonance imaging (MRI) of the abdomen. A fat-saturated multi-gradient echo sequence with 12 echoes (TR=200ms; TE-initial 0.99ms; Delta-TE 1.41ms; 12 echoes; flip-angle: 20°) was used for the R2* quantification of the liver and the pancreas. Parameter maps were analyzed using regions of interest (3 in the liver and 2 in the pancreas) and R2* values were correlated.

RESULTS

59/81 patients had a liver R2*≥70 1/s of which 10/59 patients had a pancreas R2*≥50 1/s. No patient presented with a liver R2*<70 1/s and pancreas R2*≥50 1/s. All patients with pancreas R2* values≥50 1/s had liver R2* values≥70 1/s. ROC analysis resulted in a threshold of 209.4 1/s for liver R2* values to identify HFE positive patients with pancreas R2* values≥50 1/s with a median specificity of 78.87% and a median sensitivity of 90%.

CONCLUSION

In patients with HHC R2* relaxometry of the pancreas should be performed when liver iron overload is present and can be omitted in cases with no sign of hepatic iron.

Combined biomarker testing for the prediction of left ventricular remodelling in ST-elevation myocardial infarction

Objective

The utility of different biomarkers for the prediction of left ventricular remodelling (LVR) following ST-elevation myocardial infarction (STEMI) has been evaluated in several studies. However, very few data exist on the prognostic value of combined biomarkers. The aim of this study was to comprehensively investigate the prognostic value for LVR of routinely available biomarkers measured after reperfused STEMI.

Methods

Serial measurements of N-terminal pro-B-type natriuretic peptide (NT-proBNP), high-sensitivity cardiac troponin T (hs-cTnT), aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH) and high-sensitivity C reactive protein (hs-CRP) were performed in 123 patients with STEMI treated with primary percutaneous coronary intervention in this prospective observational study. Patients underwent cardiac MRI at 2 (1–4) and 125 (121–146) days after infarction. An increase in end-diastolic volume of ≥20% was defined as LVR.

Results

LVR occurred in 16 (13%) patients. Peak concentrations of the following biomarkers showed significant areas under the curves (AUCs) for the prediction of LVR—NT-proBNP: 0.68 (95% CI 0.59 to 0.76, p=0.03), hs-cTnT: 0.75 (95% CI 0.66 to 0.82, p<0.01), AST: 0.72 (95% CI 0.63 to 0.79, p<0.01), ALT: 0.66 (95% CI 0.57 to 0.75, p=0.03), LDH: 0.78 (95% CI 0.70 to 0.85, p<0.01) and hs-CRP: 0.63 (95% CI 0.54 to 0.72, p=0.05). The combination of all biomarkers yielded a significant increase in AUC to 0.85 (95% CI 0.77 to 0.91) (all vs NT-proBNP: p=0.02, all vs hs-cTnT: p=0.02, all vs AST: p<0.01, all vs ALT: p<0.01, all vs hs-CRP: p<0.01 and all vs LDH: p=0.04).

Conclusions

In patients with reperfused STEMI, the combined assessment of peak NT-proBNP, hs-cTnT, AST, ALT, hs-CRP and LDH provide incremental prognostic information for the prediction of LVR when compared with single-biomarker measurement.

Cine-Computed Tomographic Assessment of Regional Renal Blood Flow

The new modality of cine-computed tomography was used to assess regional renal blood flow following hemorrhagic hypotension and administration of atrial natriuretic factor (ANF). As has also been established with other techniques, hypotension induced by hemorrhage caused cortical blood flow to fall from 5.3 (SD 0.8) to 2.1 (SD 1.1) ml min−1g−1 (p<0.005; n = 7) proportionally more than inner medullary blood flow which fell from 0.45 (SD 0.24), to 0.26 (SD 0.08) ml min−1g−1 (p<0.05) so that the ratio of the cortical to inner medullary blood flow decreased from 11.8 (SD 4.8) to 8.2 (SD 5.1) (p<0.01). In contrast, during natriuresis induced by ANF, cortical blood flow was unaltered (5.8, SD 1.1, vs 5.4, SD 0.9 ml min−1g−1; NS; n = 5) while inner medullary blood flow declined from 0.66 (SD 0.13) to 0.51 (SD 0.11) (p < 0.005) so the ratio of cortical to inner medullary blood flow increased from 8.8 (SD 1.3) to 10.9 (SD 1.7) (p<0.005). These results indicate that cine-CT appears to be an appropriate technique for demonstrating changes in distribution of intrarenal blood flow. Cine-CT may, therefore, be an attractive alternative for measuring regional renal blood flow.

Control of Hepatic Tumor Hemorrhage by Transcatheter Embolization with Ethibloc

Two patients with abdominal hemorrhage from a hepatic tumor underwent transcatheter embolization using Ethibloc. The hemorrhage ceased rapidly in both patients. No complications related to the embolization procedure were observed. One patient is doing well after 4 years. The second patient died of extensive metastatic disease eleven weeks after embolization. Control angiography after 14 months and 2 weeks, respectively, demonstrated persistent occlusion of the embolized hepatic arteries. Ethibloc offers the advantage of permanent vascular occlusion and appears to be a safe and effective embolization material for partial occlusion of the hepatic arteries.

Relation of inflammatory markers with myocardial and microvascular injury in patients with reperfused ST-elevation myocardial infarction

BACKGROUND

In patients with acute ST-elevation myocardial infarction (STEMI), elevated concentrations of inflammatory markers are correlated with worse clinical outcome. The aim of this study was comprehensively to investigate the relationship of circulating markers of inflammation with myocardial and microvascular damage after STEMI.

METHODS

In 111 consecutive STEMI patients, blood samples were obtained on admission and from day 1 to day 4 after primary percutaneous coronary intervention and analysed for high-sensitivity C-reactive protein (hs-CRP), white blood cell count and fibrinogen. Cardiac magnetic resonance imaging was performed within the first week and 4 months after primary percutaneous coronary intervention.

RESULTS

Peak concentrations of hs-CRP (20.5 (9.6-44.4) mg/L), white blood cell count (12.4 (10.5-15.3) G/L) and fibrinogen (3640 (3150-4550) mg/L) showed significant correlations with both infarct size ( r=0.31 to 0.41; P<0.01) and left ventricular ejection fraction ( r=-0.29 to -0.39; P<0.01) assessed in the acute as well as chronic stage following STEMI. Furthermore, peak concentrations of these inflammatory markers were significantly higher in patients with microvascular obstruction compared to patients without microvascular obstruction ( P⩽0.01). C-statistics revealed that the prognostic values of all three biomarkers for the prediction of large chronic infarct size (>8% of left ventricular myocardial mass) were moderate without significant differences (area under the curve: hs-CRP 0.73 (95% confidence interval (CI) 0.63-0.82), white blood cell count 0.67 (95% CI 0.56-0.78) and fibrinogen 0.69 (95% CI 0.59-0.79); all P>0.12). Combination of inflammatory markers did not significantly increase the area under the curve ( P>0.05).

CONCLUSION

In reperfused STEMI patients, increased levels of hs-CRP, white blood cell count and fibrinogen are associated with decreased left ventricular function and more pronounced myocardial damage at baseline and 4 months after infarction.

Hyperperfusion Syndrome of the Deltoid Muscle after Subclavian Artery Angioplasty and Stenting

Purpose:

To report a case of hyperperfusion syndrome of the deltoid muscle after percutaneous transluminal angioplasty of a symptomatic high-grade subclavian artery stenosis.

Case Report:

Immediately after balloon dilation of a left-sided subclavian artery stenosis, a 53-year-old man developed severe ipsilateral shoulder pain and swelling. Computed tomographic angiography revealed no extravasation or hematoma. Sonography showed massive edema and increased anteroposterior diameter of the left deltoid muscle (3.5 cm compared to 2.0 cm on the right). Hyperperfusion syndrome was suspected, and decompression by anterolateral fasciotomy was performed. Subsequently, both pain and swelling decreased. At day 3, the skin incision, which was temporarily covered with a synthetic skin substitute, was sutured; the wound healed uneventfully. Two weeks after surgery, both muscle strength and shoulder movements showed no restrictions.

Conclusions:

Hyperperfusion syndrome after endovascular treatment of subclavian artery stenosis should be considered in the differential diagnosis of atypical muscle pain in the upper extremity. It may present as a compartment syndrome requiring surgical decompression.

Sirolimus-Eluting versus Bare-Metal Low-Profile Stent for Renal Artery Treatment (GREAT Trial): Angiographic Follow-up after 6 Months and Clinical Outcome up to 2 Years

Purpose:

To evaluate the patency of sirolimus-eluting stents (SES) compared to bare-metal stents (BMS) in the treatment of atherosclerotic renal artery stenosis (RAS).

Methods:

Between November 2001 to June 2003, 105 consecutive symptomatic patients (53 men; mean age 65.7 years) with RAS were treated with either a bare-metal (n=52) or a drug-eluting (n=53) low-profile Palmaz-Genesis peripheral stent at 11 centers in a prospective nonrandomized trial. The primary endpoint was the angiographic result at 6 months measured with quantitative vessel analysis by an independent core laboratory. Secondary endpoints were technical and procedural success, clinical patency [no target lesion revascularization (TLR)], blood pressure and antihypertensive drug use, worsening of renal function, and no major adverse events at 1, 6, 12, and 24 months.

Results:

At 6 months, the overall in-stent diameter stenosis for BMS was 23.9%±22.9% versus 18.7%±15.6% for SES (p=0.39). The binary restenosis rate was 6.7% for SES versus 14.6% for the BMS (p=0.30). After 6 months and 1 year, TLR rate was 7.7% and 11.5%, respectively, in the BMS group versus 1.9% at both time points in the SES group (p=0.21). This rate remained stable up to the 2-year follow-up but did not reach significance due to the small sample. Even as early as 6 months, both types of stents significantly improved blood pressure and reduced antihypertensive medication compared to baseline (p<0.01). After 6 months, renal function worsened in 4.6% of the BMS patients and in 6.9% of the SES group. The rate of major adverse events was 23.7% for the BMS group and 26.8% for the SES at 2 years (p=0.80).

Conclusion:

The angiographic outcome at 6 months did not show a significant difference between BMS and SES. Renal artery stenting with both stents significantly improved blood pressure. Future studies with a larger patient population and longer angiographic follow-up are warranted to determine if there is a significant benefit of drug-eluting stents in treating ostial renal artery stenosis.

Accuracy and feasibility of three different methods for software-based image fusion in whole-body PET and CT

BACKGROUND

Even as PET/CT provides valuable diagnostic information in a great number of clinical indications, availability of hybrid PET/CT scanners is mainly limited to clinical centers. A software-based image fusion would facilitate combined image reading of CT and PET data sets if hardware image fusion is not available. To analyze the relevance of retrospective image fusion of separately acquired PET and CT data sets, we studied the accuracy, practicability and reproducibility of three different image registration techniques.

METHODS

We evaluated whole-body 18F-FDG-PET and CT data sets of 71 oncologic patients. Images were fused retrospectively using Stealth Station System, Treon (Medtronic Inc., Louisville, CO, USA) equipped with Cranial4 Software. External markers fixed to a vacuum mattress were used as reference for exact repositioning. Registration was repeated using internal anatomic landmarks and Automerge software, assessing accuracy for all three methods, measuring distances of liver representation in CT and PET with reference to a common coordinate system.

RESULTS

On first measurement of image fusions with external markers, 53 were successful, 16 feasible and 2 not successful. Using anatomic landmarks, 42 were successful, 26 feasible and 3 not successful. Using Automerge Software only 13 were successful. The mean distance between center points in PET and CT was 7.69±4.96 mm on first, and 7.65±4.2 mm on second measurement. Results with external markers correlate very well and inaccuracies are significantly lower (P<0.001) than results using anatomical landmarks (10.38±6.13 mm and 10.83±6.23 mm). Analysis revealed a significantly faster alignment using external markers (P<0.001).

CONCLUSIONS

External fiducials in combination with immobilization devices and breathing protocols allow for highly accurate image fusion cost-effectively and significantly less time, posing an attractive alternative for PET/CT interpretation when a hybrid scanner is not available.

Comparison of Two Electromagnetic Navigation Systems For CT-Guided Punctures: A Phantom Study

PURPOSE

We compared the targeting accuracy and reliability of two different electromagnetic navigation systems for manually guided punctures in a phantom.

MATERIALS AND METHODS

CT data sets of a gelatin filled plexiglass phantom were acquired with 1, 3, and 5 mm slice thickness. After paired-point registration of the phantom, a total of 480 navigated stereotactic needle insertions were performed manually using electromagnetic guidance with two different navigation systems (Medtronic Stealth Station: AxiEM; Philips: PercuNav). A control CT was obtained to measure the target positioning error between the planned and actual needle trajectory.

RESULTS

Using the Philips PercuNav, the accomplished Euclidean distances were 4.42 ± 1.33 mm, 4.26 ± 1.32 mm, and 4.46 ± 1.56 mm at a slice thickness of 1, 3, and 5 mm, respectively. The mean lateral positional errors were 3.84 ± 1.59 mm, 3.84 ± 1.43 mm, and 3.81 ± 1.71 mm, respectively. Using the Medtronic Stealth Station AxiEM, the Euclidean distances were 3.86 ± 2.28 mm, 3.74 ± 2.1 mm, and 4.81 ± 2.07 mm at a slice thickness of 1, 3, and 5 mm, respectively. The mean lateral positional errors were 3.29 ± 1.52 mm, 3.16 ± 1.52 mm, and 3.93 ± 1.68 mm, respectively.

CONCLUSION

Both electromagnetic navigation devices showed excellent results regarding puncture accuracy in a phantom model. The Medtronic Stealth Station AxiEM provided more accurate results in comparison to the Philips PercuNav for CT with 3 mm slice thickness. One potential benefit of electromagnetic navigation devices is the absence of visual contact between the instrument and the sensor system. Due to possible interference with metal objects, incorrect position sensing may occur. In contrast to the phantom study, patient movement including respiration has to be compensated for in the clinical setting.

KEY POINTS

• Commercially available electromagnetic navigation systems have the potential to improve the therapeutic range for CT guided percutaneous procedures by comparing the needle placement accuracy on the basis of planning CT data sets with different slice thickness. Citation Format: • Putzer D, Arco D, Schamberger B et al. Comparison of Two Electromagnetic Navigation Systems For CT-Guided Punctures: A Phantom Study. Fortschr Röntgenstr 2016; 188: 470 - 478.

Sonoelastographic Findings of Carpal Tunnel Injection

PURPOSE

The objectives of this study were to compare sonoelastographic color findings of the perineural area between carpal tunnel syndrome patients and healthy volunteers, and to analyze elastographic findings in that area before and immediately after intracarpal tunnel injection in carpal tunnel syndrome patients.

MATERIALS AND METHODS

We studied both hands of 15 healthy volunteers (7 men, 8 women; mean age: 60.1 years, range: 41 - 88 years) and 72 hands from 70 patients with symptomatic carpal tunnel syndrome (24 men, 46 women; mean age: 54.2 years, range: 24 - 83 years). Sonoelastographic color distribution was assessed in the perineural area between the median nerve and adjacent flexor tendons. The color elastograms were graded using the following system: Grade 1 as red (softest), grade 2 as yellow (soft), grade 3 as green (hard), grade 4 as blue (hardest). The patients were treated with corticosteroid injection and were reassessed with sonoelastography immediately after the injection.

RESULTS

The median color grading in the perineural area of carpal tunnel syndrome patients was grade 3 (3.1 ± 0.3, mean ± 95 % Cl), which was stiffer than that of healthy volunteers (grade 1, 1.9 ± 0.4) (p < 0.0001). Immediately after injection, the diffusion of the injected fluid was observed as having a softer appearance (grade 1, 1.4 ± 0.2) (p < 0.0001).

CONCLUSION

The perineural area surrounding the median nerve in carpal tunnel syndrome patients was stiffer than that in healthy volunteers. Diffusion of the injected fluid in the carpal tunnel was seen as a softer finding after injection in real time using sonoelastography.

Strain Elastography of Breast and Prostata Cancer: Similarities and Differences

Typically both breast and prostate cancer present as tissue with decreased elasticity. Palpation is the oldest technique of tumor detection in both organs and is based on this principle. Thus an operator can grade a palpable mass as suspicious for cancer. Strain elastography as modern ultrasound technique allows the visualization of tissue elasticity in a color coded elastogram and can be understood as technical finger. The following article shows similarities and differences of ultrasound strain elastography in the diagnosis of breast and prostate cancer.

KEY POINTS

• In prostata cancer elastography, in breast cancer B-mode is the primary sonographic search modality. • The diagnostic value of the search modalities change with increasing age.• A cut-off value for a strain ratio is hard to obtain in the elastography of the prostata, because there is no stabile reference tissue in the prostata.