Complexity of PEComas : Diagnostic approach, molecular background, clinical management.

Perivascular epithelioid cell neoplasms (PEComas) are a family of mesenchymal neoplasms with features of both melanotic and smooth muscle differentiation. PEComa morphology is highly variable and encompasses epithelioid to spindle cells often with clear cytoplasm and prominent nucleoli. Molecularly, most PEComas are defined by a loss of function of the TSC1/TSC2 complex. Additionally, a distinct small subset of PEComas harboring rearrangements of the TFE3 (Xp11) gene locus has been identified. By presenting a series of three case reports with distinct features, we demonstrate diagnostic pitfalls as well as the importance of molecular work-up of PEComas because of important therapeutic consequences.

[Complexity of PEComas : Diagnostic approach, molecular background, clinical management (German version)]. / Komplexität von PEComen : Diagnose, Molekulargenetik, klinisches Management.

Perivascular epithelioid cell neoplasms (PEComas) are a family of mesenchymal neoplasms with features of both melanotic and smooth muscle differentiation. PEComa morphology is highly variable and encompasses epithelioid to spindle cells often with clear cytoplasm and prominent nucleoli. Molecularly, most PEComas are defined by a loss of function of the TSC1/TSC2 complex. Additionally, a distinct small subset of PEComas harboring rearrangements of the TFE3 (Xp11) gene locus has been identified. By presenting a series of three case reports with distinct features, we demonstrate diagnostic pitfalls as well as the importance of molecular work-up of PEComas because of important therapeutic consequences.

Assessing liver function by liver enhancement during the hepatobiliary phase with Gd-EOB-DTPA-enhanced MRI at 3 Tesla.

OBJECTIVES: The purpose of this study was to evaluate the usefulness of Gd-EOB-DTPA-enhanced 3-T MRI to determine the hepatic functional reserve expressed by the model for end-stage liver disease (MELD) score. METHODS: A total of 121 patients with normal liver function (NLF; MELD score ≤ 10) and 29 patients with impaired liver function (ILF; MELD score > 10) underwent contrast-enhanced MRI with a hepatocyte-specific contrast agent at 3T. T1-weighted volume interpolated breath-hold examination (VIBE) sequences with fat suppression were acquired before and 20 min after contrast injection. Relative enhancement (RE) between plain signal intensity and contrast-enhanced signal intensity was calculated and was used to determine Gd-EOB-DTPA uptake into the liver parenchyma for patients with different MELD scores. RESULTS: RE differed significantly (p ≤ 0.001) between patients with NLF (87.2 ± 29.5 %) and patients with ILF (45.4 ± 26.5 %). The optimal cut-off value for RE to differentiate NLF from ILF was 47.7 % (AUC 0.87). This cut-off value showed a sensitivity of 82.8 % and a specificity of 92.7 % for the differentiation of the analysed groups. CONCLUSION: Gd-EOB-DTPA uptake in hepatocytes is strongly affected by liver function. Gd-EOB-DTPA-enhanced MRI and assessment of RE during the hepatobiliary phase (HBP) may serve as a useful image-based test in liver imaging for determining regional and global liver function. KEY POINTS: Hepatic uptake of Gd-EOB-DTPA is strongly affected by liver function. Relative enhancement during HBP in GD-EOB-DTPA MRI correlates with the MELD score. Assessment of relative enhancement may help improve treatment in routine clinical practice.

Wireless point-of-care ultrasound: First experiences with a new generation handheld device.

AIM: To evaluate the diagnostic reliability of a new generation wireless point-of care ultrasound device for abdominal and thoracic findings. MATERIAL AND METHODS: 40 patients (16 females, 24 males 19 -80 years, on average 56.1 years) were scanned by an experienced examiner using the new wireless Vscan Air device for abdominal and thoracic findings. The probe frequencies were 2-5 MHz (convex probe) and 3-12 MHz for the linear probe. As a reference standard, all patients were also examined using high-end ultrasound (LOGIQ E9/LOGIQ E10). Results were interpreted independently by two examiners in consensus, also with regard to the image quality (0-4, from not assessable = 0, to excellent 4). RESULTS: In all 40 patients (100%) examination with conventional high-end ultrasound and the Vscan Air ultrasound device was feasible. Sensitivity, specificity, positive and negative predictive value for the diagnosis of abdominal and thoracic findings were 63.3%, 100%, 100%, and 40%, respectively. Most main diagnostic findings were detected using the mobile device compared to the high-end ultrasound. Limitations were found regarding characterization and classification of hepatic and renal tumorous lesions.Image quality revealed mostly minor diagnostic limitations for the mobile device, mean 2.9 (SD ± 0.300) and was excellent or with only minor diagnostic limitations for conventional high-end ultrasound, mean 3.25 (SD ± 0.438). CONCLUSION: Due to its easy application and its high diagnostic reliability, point-of-care ultrasound systems of the latest generation represent a valuable imaging method for the primary assessment of abdominal and thoracic findings, especially in patients on intensive care units or in emergency situations.

Hepatocellular carcinoma progression during bridging before liver transplantation.

BACKGROUND: Recipient selection for liver transplantation in hepatocellular carcinoma (HCC) is based primarily on criteria affecting the chance of long-term success. Here, the relationship between pretransplant bridging therapy and long-term survival was investigated in a subgroup analysis of the SiLVER Study. METHODS: Response to bridging, as defined by comparison of imaging at the time of listing and post-transplant pathology report, was categorized into controlled versus progressive disease (more than 20 per cent tumour growth or development of new lesions). RESULTS: Of 525 patients with HCC who had liver transplantation, 350 recipients underwent pretransplant bridging therapy. Tumour progression despite bridging was an independent risk factor affecting overall survival (hazard ratio 1.80; P = 0.005). For patients within the Milan criteria (MC) at listing, mean overall survival was longer for those with controlled versus progressive disease (6.8 versus 5.8 years; P < 0.001). Importantly, patients with HCCs outside the MC that were downsized to within the MC before liver transplantation had poor outcomes compared with patients who never exceeded the MC (mean overall survival 6.2 versus 6.6 years respectively; P = 0.030). CONCLUSION: Patients with HCCs within the MC that did not show tumour progression under locoregional therapy had the best outcomes after liver transplantation. Downstaging into the limits of the MC did not improve the probability of survival.Prognostic factors determining the long-term success of liver transplantation in patients with hepatocellular carcinoma are still under discussion. A subgroup analysis of the SiLVER trial showed that disease control under bridging therapy is strongly associated with improved prognosis in terms of overall survival. However, in tumours exceeding the limits of the Milan criteria, downstaging did not restore the probability of survival compared with that of patients within the Milan criteria.

Influence of hepatic fibrosis and inflammation: Correlation between histopathological changes and Gd-EOB-DTPA-enhanced MR imaging.

OBJECTIVE: To evaluate the influence of an active inflammatory process in the liver on Gd-EOB-DTPA-enhanced MR imaging in patients with different degrees of fibrosis/cirrhosis. MATERIAL AND METHODS: Overall, a number of 91 patients (61 men and 30 women; mean age 58 years) were included in this retrospective study. The inclusion criteria for this study were Gd-EOB-DTPA-enhanced MRI of the liver and histopathological evaluation of fibrotic and inflammatory changes. T1-weighted VIBE sequences of the liver with fat suppression were evaluated to determine the relative signal change (RE) between native and hepatobiliary phase (20min). In simple and multiple linear regression analyses, the influence of liver fibrosis/cirrhosis (Ishak score) and the histopathological degree of hepatitis (Modified Hepatic Activity Index, mHAI) on RE were evaluated. RESULTS: RE decreased significantly with increasing liver fibrosis/cirrhosis (p < 0.001) and inflammation (mHAI, p = 0.004). In particular, a correlation between RE and periportal or periseptal boundary zone hepatitis (moth feeding necrosis, mHAI A, p = 0.001) and portal inflammation (mHAI D, p < 0.001) was observed. In multiple linear regression analysis, both the degree of inflammation and the degree of fibrosis were significant predictors for RE (p < 0.01). CONCLUSION: The results of this study suggest that the MR-based hepatic enhancement index RE is not only influenced by the degree of fibrosis, but also by the degree of inflammation.

Kidney Failure After Occlusion of Accessory Renal Arteries in Endovascular Abdominal Aneurysm Repair.

PURPOSE: To evaluate the incidence of acute renal failure and chronic kidney disease due to occlusion of accessory renal arteries during endovascular aneurysm repair of infrarenal abdominal aortic aneurysm. MATERIAL AND METHODS: We retrospectively reviewed the course of 181 patients (mean age, 71, SD ± 9  years) who underwent EVAR of infrarenal abdominal aortic aneurysm. The renal vessel anatomy was analyzed in all pre- and postoperative CT scans. Diameter and origin of accessory renal arteries were evaluated. Renal function was determined by pre- and postoperative serum creatinine and eGFR levels. Long-term follow-up (>3 months) of patients was available in 121 cases (66.9%). Acute kidney injury and chronic kidney failure were defined according to guidelines of "Kidney Disease: Improving Global Outcomes" (KDIGO). RESULTS: In 65 of 181 patients (33.9%), 82 accessory renal arteries were identified preoperatively. In 19 of 181 patients (10.5%), one or more accessory renal arteries were covered and subsequently occluded by the implanted stent-graft device. Neither acute kidney injury (10.3% vs 12.5%; p = .785) nor chronic kidney disease (10.7% vs 15.38%; p = .452) was detected significantly more often in patients with covered accessory renal artery. The only significant predictor of acute kidney injury was the preoperative serum creatinine level (1.12 mg/dl vs. 0.98 mg/dl; p = .03). Significant predictors for chronic kidney disease were preoperative serum creatinine, eGFR, and impaired renal function (p < .001). CONCLUSION: Coverage of accessory renal artery due to stent-graft does not lead either to temporary acute kidney injury after endovascular aneurysm repair or to chronic kidney disease. LEVEL OF EVIDENCE: Level II b.

Stereotactically navigated percutaneous microwave ablation (MWA) compared to conventional MWA: a matched pair analysis.

PURPOSE: To compare CT-navigated stereotactic microwave ablation (SMWA) to non-navigated conventional MWA (CMWA) for percutaneous ablation of liver malignancies. METHODS: A matched pair analysis of 36 patients who underwent MWA of primary or secondary liver malignancies (10 hepatocellular carcinoma and 8 metastases) was conducted. A total of 18 patients undergoing SMWA were included in this prospective study. Patients were matched in terms of tumor size, liver segment and entity to retrospective CMWA procedures. The endpoints were procedure time, accuracy of needle placement, technical success rate, complication rate and dose-length product (DLP). RESULTS: The procedure durations were 23.9 min (SD 3.7) for CMWA and 21.8 min (SD 16.3) for SMWA (p = 0.22). The procedural accuracy for SMWA and CMWA was identical for both groups (3.7 mm). The total DLP was significantly lower for SMWA than for CMWA (2115 mGy cm (SD 276) vs. 3109 mGy cm (SD 1137), respectively; p < 0.01). Complete ablation without residual tumor was observed in 94% (17 of 18) of SMWA and in 83% (15 of 18) of CMWA patients (p = 0.31). No complications occurred. CONCLUSIONS: SMWA is highly accurate and reduces the radiation dose without increasing the procedure time.

Evaluation of integrated color-coded perfusion analysis for contrast-enhanced ultrasound (CEUS) after percutaneous interventions for malignant liver lesions: First results.

BACKGROUND:  With the rising number of percutaneous ablation therapies in malignant liver lesions there is a need of reliable diagnostics after the intervention to differentiate between reactive changes and tumor. PURPOSE: To assess the success of percutaneous ablation therapies for malignant liver lesions using CEUS with perfusion analysis. MATERIAL AND METHODS: Retrospective analysis of perfusion analysis for 67 patients with 94 malignant liver lesions, treated with ablation therapies. The lesions were 70 hepatocellular carcinomas (HCC), 18 metastases, 4 cholangiocellular carcinomas (CCC), 2 lesions remained unclear. CEUS was performed after bolus injection of 1.6-2.4 ml of sulfur-hexafluoride microbubbles. The perfusion analysis was calculated using Peak, TTP, mTT and AUC with integrated software during the late arterial to early portal-venous phase for approximately 9 sec (5-15 sec). For the evaluation of the success after percutaneous treatment the perfusion results were compared to the follow-up control after 6 months with CT and MRI and CEUS. RESULTS: Perfusion analyses after percutaneous treatment of malignant liver lesions showed highly significant perfusion differences when comparing the center to the surrounding tissue and the margins (p<0.0001) for Peak and also for AUC. 62 lesions were successfully treated, meaning there was no local recurrence after 6 months. In cases of residual tumor CEUS showed a nodular marginal enhancement, the corresponding perfusion analyses showed nodular red and yellow pseudo-color shades. CONCLUSIONS: Using CEUS and perfusion analysis, a critical analysis of post-ablation defects in malignant liver lesions is possible. With the help of pseudo-colors, remaining tumor-vascularization can be detected.

Effect of irreversible electroporation of prostate cancer on microcirculation: Imaging findings in contrast-enhanced T1-weighted 3D MRI.

OBJECTIVES: Irreversible electroporation (IRE) is a novel focal ablation technique applicable for treatment of prostate cancer (PCa). We aim to evaluate imaging findings of T1-weighted contrast-enhanced MRI after percutaneous IRE of low-risk PCa. METHODS: A total of 13 male patients underwent IRE of focal low-risk PCa and were included in this analysis. Prostate IRE was conducted using 2-4 electrodes being placed under CT-fluoroscopy guidance. Dynamic contrast-enhanced 3D isotropic fat-saturated T1-weighted MRI (DCE-MRI) was performed 24-72 hours before and 24-72 hours after ablation. RESULTS: Ablated prostate was either homogeneously (8/13 [62%]) or heterogeneously (5/13 [38%]) hypo attenuating. Peripheral contrast enhancement manifesting as a hyper attenuating margin was observed during the arterial (60 sec) (3/13 [23%]) and venous (240 sec) (10/13 [77%]) phase. The ablation defect showed a sharp (8/13 [62%]) or blurry (5/13 [38%]) margin. CONCLUSIONS: The results show a venous peripheral rim enhancement in most of the cases, indicating reactive hyperaemia. The heterogeneous appearance of the defect zone in some cases may be secondary to sustained vascularization.

Multivariable analysis of clinical influence factors on liver enhancement of Gd-EOB-DTPA-enhanced 3T MRI.

PURPOSE: The purpose of this study was to identify clinical factors influencing Gd-EOB-DTPA liver uptake in patients with healthy liver parenchyma. MATERIALS AND METHODS: A total of 124 patients underwent contrast-enhanced MRI with a hepatocyte-specific contrast agent at 3 T. T1-weighted volume interpolated breath-hold examination (VIBE) sequences with fat suppression were acquired before and 20 minutes after contrast injection. The relative enhancement (RE) between plain and contrast-enhanced signal intensity was calculated. Simple and multiple linear regression analyses were performed to evaluate clinical factors influencing the relative enhancement. Patients were subdivided into three groups according to their relative liver enhancement (HRE, RE ≥ 100 %; MRE, 100 % > RE > 50 %; NRE, RE ≤ 50 %) and were analyzed according to the relevant risk factors. RESULTS: Simple regression analyses revealed patient age, transaminases (AST, ALT, GGT), liver, spleen and delta-liver volume (the difference between the volumetrically measured liver volume and the estimated liver volume based on body weight) as significant factors influencing relative enhancement. In the multiple analysis the transaminase AST, spleen and delta liver volume remained significant factors influencing relative enhancement. Delta liver volume showed a significant difference between all analyzed groups. CONCLUSION: Liver enhancement in the hepatobiliary phase depends on a variety of factors. Body weight-adapted administration of Gd-EOB-DTPA may lead to inadequate liver enhancement after 20 minutes especially when the actual liver volume differs from the expected volume. KEY POINTS: • Differences between actual and expected liver volume can cause inadequate liver enhancement after 20 min. • A liver volume-adapted dose of Gd-EOB-DTPA may help to improve liver enhancement.

Impact of liver cirrhosis on liver enhancement at Gd-EOB-DTPA enhanced MRI at 3 Tesla.

PURPOSE: The purpose of this study was to assess differences in enhancement effects of liver parenchyma between normal and cirrhotic livers on dynamic, Gd-EOB-DTPA enhanced MRI at 3T. MATERIALS AND METHODS: 93 patients with normal (n=54) and cirrhotic liver (n=39; Child-Pugh class A, n=18; B, n=16; C, n=5) underwent contrast-enhanced MRI with liver specific contrast media at 3T. T1-weighted volume interpolated breath hold examination (VIBE) sequences with fat suppression were acquired before contrast injection, in the arterial phase (AP), in the late arterial phase (LAP), in the portal venous phase (PVP), and in the hepatobiliary phase (HBP) after 20 min. The relative enhancement (RE) of the signal intensity of the liver parenchyma was calculated for all phases. RESULTS: Mean RE was significantly different among all evaluated groups in the hepatobiliary phase and with increasing severity of liver cirrhosis, a decreasing, but still significant reduction of RE could be shown. Phase depending changes of RE for each group were observed. In case of non-cirrhotic liver or Child-Pugh Score A cirrhosis mean RE showed a significant increase between AP, LAP, PVP and HBP. For Child-Pugh B+C cirrhosis RE increased until PVP, however, there was no change in case of B cirrhosis (p=0.501) and significantly reduced in case of C cirrhosis (p=0.043) during HBP. CONCLUSION: RE of liver parenchyma is negatively affected by increased severity of liver cirrhosis, therefore diagnostic value of HBP could be limited in case of Child Pugh B+C cirrhosis.