Current use of percutaneous image-guided tumor ablation for the therapy of liver tumors: lessons learned from the registry of the German Society for Interventional Radiology and Minimally Invasive Therapy (DeGIR) 2018-2022

OBJECTIVES

Percutaneous image-guided tumor ablation of liver malignancies has become an indispensable therapeutic procedure. The aim of this evaluation of the prospectively managed multinational registry of the voluntary German Society for Interventional Radiology and Minimally Invasive Therapy (DeGIR) was to analyze its use, technical success, and complications in clinical practice.

MATERIALS AND METHODS

All liver tumor ablations from 2018 to 2022 were included. Technical success was defined as complete ablation of the tumor with an ablative margin.

RESULTS

A total of 7228 liver tumor ablations from 136 centers in Germany and Austria were analyzed. In total, 31.4% (2268/7228) of patients were female. Median age was 67 years (IQR 58-74 years). Microwave ablation (MWA) was performed in 65.1% (4703/7228), and radiofrequency ablation (RFA) in 32.7% (2361/7228). Of 5229 cases with reported tumor etiology, 60.3% (3152/5229) of ablations were performed for liver metastases and 37.3% (1950/5229) for hepatocellular carcinoma. The median lesion diameter was 19 mm (IQR 12-27 mm). In total, 91.8% (6636/7228) of ablations were technically successful. The rate of technically successful ablations was significantly higher in MWA (93.9%, 4417/4703) than in RFA (87.3%, 2061/2361) (p < 0.0001). The total complication rate was 3.0% (214/7228) and was significantly higher in MWA (4.0%, 189/4703) than in RFA (0.9%, 21/2361, p < 0.0001). Additional needle track ablation did not increase the rate of major complications significantly (24.8% (33/133) vs. 28.4% (23/81), p = 0.56)).

CONCLUSION

MWA is the most frequent ablation method. Percutaneous image-guided liver tumor ablations have a high technical success rate, which is higher for MWA than RFA. The complication rate is generally low but is higher for MWA than RFA.

CLINICAL RELEVANCE STATEMENT

Percutaneous image-guided liver ablation using microwave ablation and radiofrequency ablation are effective therapeutic procedures with low complication rates for the treatment of primary and secondary liver malignancies.

KEY POINTS

• Percutaneous image-guided liver tumor ablations have a high technical success rate, which is higher for microwave ablation than radiofrequency ablation. • Microwave ablation is the most frequent ablation method ahead of radiofrequency ablation. • The complication rate is generally low but is higher for microwave ablation than radiofrequency ablation.

Preoperative Computed Tomography Volumetry and Graft Weight Estimation of Left Lateral Segment in Pediatric Living Donor Liver Transplant

OBJECTIVES

Liver volumetry based on a computed tomography scan is widely used to estimate liver volume before any liver resection, especially before living donorliver donation. The 1-to-1 conversion rule for liver volume to liver weight has been widely adopted; however, debate continues regarding this approach. Therefore, we analyzed the relationship between the left-lateral lobe liver graft volume and actual graft weight.

MATERIALS AND METHODS

This study retrospectively included consecutive donors who underwent left lateral hepatectomy for pediatric living donor liver transplant from December 2008 to September 2020. All donors were healthy adults who met the evaluation criteria for pediatric living donor liver transplant and underwent a preoperative contrast-enhanced computed tomography scan. Manual segmentation of the leftlateral liverlobe for graft volume estimation and intraoperative measurement of an actual graft weight were performed. The relationship between estimated graft volume and actual graft weight was analyzed.

RESULTS

Ninety-four living liver donors were included in the study. The mean actual graft weight was ~283.4 ± 68.5 g, and the mean graft volume was 244.9 ± 63.86 mL. A strong correlation was shown between graft volume and actual graft weight (r = 0.804; P < .001). Bland-Altman analysis revealed an interobserver agreement of 38.0 ± 97.25, and intraclass correlation coefficient showed almost perfect agreement(r = 0.840; P < .001). The conversion formula for calculating graft weight based on computed tomography volumetry was determined based on regression analysis: 0.88 × graft volume + 41.63.

CONCLUSIONS

The estimation of left liver graft weight using only the 1-to-1 rule is subject to measurable variability in calculated graft weights and tends to underestimate the true graft weight. Instead, a different, improved conversion formula should be used to calculate graft weight to more accurately determine donor graft weight-to-recipient body weightratio and reduce the risk of underestimation of liver graft weightin the donor selection process before pediatric living donor liver transplant.

Bilobar Radioembolization Carries the Risk of Radioembolization-Induced Liver Disease in the Treatment of Advanced Hepatocellular Carcinoma: Safety and Efficacy Comparison to Systemic Therapy with Atezolizumab/Bevacizumab

Recommended treatment options for advanced-stage hepatocellular carcinoma (HCC) include systemic therapy (ST) and trans-arterial radioembolization (TARE) with Yttrium-90 (Y90). Before the approval of immune-checkpoint inhibitors, a similar safety profile was reported for TARE and ST with tyrosine kinase inhibitors (TKI). However, whole-liver treatment and underlying cirrhosis were identified as risk factors for potentially lethal radioembolization-induced liver disease (REILD). Therefore, the safety and efficacy of TARE and ST with atezolizumab/bevacizumab were compared in patients with advanced HCC involving at least both liver lobes in a retrospective real-world cohort. In total, 74 patients with new or recurrent advanced-stage HCC (BCLC stage B/C) were included if treated with either bilobar TARE (n = 33) or systemic combination therapy with atezolizumab plus bevacizumab (n = 41). Most patients had compensated liver function (90.5% were classified as Child-Pugh Score A, 73% as ALBI Grade 1) at baseline. Although not significant, patients treated with ST showed a more prolonged overall survival than those treated with Y90 TARE (7.1 months vs. 13.0 months, p = 0.07). While a similar disease control rate could be achieved with bilobar TARE and atezolizumab/bevacizumab, in the TARE group, overall survival was curtailed by the occurrence of REILD. In patients with underlying liver cirrhosis, the liver function at baseline was a predictor for REILD.

Abdominal ultrasound in head and neck squamous cell carcinoma staging: yes or no?

PURPOSE

Abdominal ultrasound is a diagnostic staging procedure for distant metastases in head and neck squamous cell carcinoma (HNSCC). However, currently performed abdominal staging procedures do not follow consistent standards. Therefore, this retrospective study on 498 patients aimed at investigating on abdominal ultrasound as a staging procedure in HNSCC.

MATERIALS AND METHODS

A retrospective analysis of 498 head and neck cancer patients treated in our Department of Head and Neck Surgery between 2008 and 2015 was performed. Disease-related data were collected over a mean follow-up time of 30.3 months, and results of abdominal ultrasound were analyzed.

RESULTS

426 patients received abdominal ultrasound as a staging procedure. 7% (29) were suspicious for metastases. In 19 cases (66%), the detected abnormalities were masses of the liver. In four patients, abdominal metastases were confirmed at the time of initial diagnosis. 16 patients developed abdominal metastases in the course of the disease (on average 623 days after initial diagnosis). 19 out of 20 patients with abdominal metastases had an N2/N3 cervical lymph node status. In this study, the negative predictive value of abdominal ultrasound for HNSCC staging was 99.03%, while the positive predictive value yielded 5.88% (N2/N3-patients).

CONCLUSION

Only in patients with locally advanced lymph-node-status (N2/N3), abdominal ultrasound can be useful as a staging investigation to exclude abdominal metastasis in HNSCC patients. For N0/N1 patients, abdominal ultrasound might be dispensed. Of note, in case of a positive result, further diagnostic procedures are mandatory.

Low bone mineral density is a prognostic factor for elderly patients with HCC undergoing TACE: results from a multicenter study

OBJECTIVES

Low bone mineral density (BMD) was recently identified as a novel risk factor for patients with hepatocellular carcinoma (HCC). In this multicenter study, we aimed to validate the role of BMD as a prognostic factor for patients with HCC undergoing transarterial chemoembolization (TACE).

METHODS

This retrospective multicenter trial included 908 treatment-naïve patients with HCC who were undergoing TACE as a first-line treatment, at six tertiary care centers, between 2010 and 2020. BMD was assessed by measuring the mean Hounsfield units (HUs) in the midvertebral core of the 11^th thoracic vertebra, on contrast-enhanced computer tomography performed before treatment. We assessed the influence of BMD on median overall survival (OS) and performed multivariate analysis including established estimates for survival.

RESULTS

The median BMD was 145 HU (IQR, 115-175 HU). Patients with a high BMD (≥ 114 HU) had a median OS of 22.2 months, while patients with a low BMD (< 114 HU) had a lower median OS of only 16.2 months (p < .001). Besides albumin, bilirubin, tumor number, and tumor diameter, BMD remained an independent prognostic factor in multivariate analysis.

CONCLUSIONS

BMD is an independent predictive factor for survival in elderly patients with HCC undergoing TACE. The integration of BMD into novel scoring systems could potentially improve survival prediction and clinical decision-making.

KEY POINTS

• Bone mineral density can be easily assessed in routinely acquired pre-interventional computed tomography scans. • Bone mineral density is an independent predictive factor for survival in elderly patients with HCC undergoing TACE. • Thus, bone mineral density is a novel imaging biomarker for prognosis prediction in elderly patients with HCC undergoing TACE.

Unloader bracing in osteoarthritis of the knee - Is there a direct effect on the damaged cartilage?

BACKGROUND

Unloading knee braces represent a conservative treatment option for non-pharmalogical management of unicompartmental osteoarthritis of the knee. Though there is consensus on the clinical effectiveness of unloading, the effect mechanism of bracing remains part of a debate. Our study was designed to assess the effect of unloader bracing on damaged cartilage via MRI cartilage mappings.

METHODS

Fourteen patients (7 female, 7 male, mean age 43.1 ± 9.4 years) with unicompartmental cartilage wear in knees with varus or valgus malalignment were enrolled. Clinical scores, radiographs and MR-graphic properties (T2/T2* mapping, T1 Delayed Gadolinium Enhanced MRI of the cartilage (dGEMRIC) mapping, high-resolution PDw sequences) of knee cartilage were recorded before and three months after brace use.

RESULTS

Bracing the knees for a mean of 14.4 ± 2.0 weeks (range 11 to 18 weeks) resulted in significant pain reduction (VAS changed from 5.9 ± 2.0 to 2.0 ± 1.3, p < 0.001) and improvement in knee function (KOOS increased from 42.1 ± 22.7 to 64.8 ± 18.7, p < 0.001). In the affected cartilage regions T2 relaxation times significantly decreased from 56.1 ± 11.4 ms to 46.5 ± 11.2 ms (p < 0.05). No changes in T1-dGEMRIC and T2* relaxation times, thickness or the extent of the damaged cartilage area could be detected.

CONCLUSIONS

Our results suggest, that unloader bracing improves the biochemical properties of the damaged cartilage by increasing collagen and proteoglycan concentration as well as decreasing the cartilage edema.

Fully automated preoperative liver volumetry incorporating the anatomical location of the central hepatic vein

The precise preoperative calculation of functional liver volumes is essential prior major liver resections, as well as for the evaluation of a suitable donor for living donor liver transplantation. The aim of this study was to develop a fully automated, reproducible, and quantitative 3D volumetry of the liver from standard CT examinations of the abdomen as part of routine clinical imaging. Therefore, an in-house dataset of 100 venous phase CT examinations for training and 30 venous phase ex-house CT examinations with a slice thickness of 5 mm for testing and validating were fully annotated with right and left liver lobe. Multi-Resolution U-Net 3D neural networks were employed for segmenting these liver regions. The Sørensen-Dice coefficient was greater than 0.9726 ± 0.0058, 0.9639 ± 0.0088, and 0.9223 ± 0.0187 and a mean volume difference of 32.12 ± 19.40 ml, 22.68 ± 21.67 ml, and 9.44 ± 27.08 ml compared to the standard of reference (SoR) liver, right lobe, and left lobe annotation was achieved. Our results show that fully automated 3D volumetry of the liver on routine CT imaging can provide reproducible, quantitative, fast and accurate results without needing any examiner in the preoperative work-up for hepatobiliary surgery and especially for living donor liver transplantation.

Bridging treatment prior to liver transplantation for hepatocellular carcinoma: radioembolization or transarterial chemoembolization?

BACKGROUND

In hepatocellular carcinoma (HCC) patients, intraarterial therapies are regularly employed as a bridge to liver transplantation to prevent tumor progression during waiting time. Objective of this study was to compare HCC recurrence after liver transplantation following TACE or radioembolization bridging treatment.

METHODS

We retrospectively analyzed prospectively collected data on 131 consecutive HCC patients who underwent liver transplantation between January 2007 and December 2017 at our liver transplant center (radioembolization n = 44, TACE n = 87). Multivariable logistic regression and cox proportional hazard regression models were used to evaluate factors associated with tumor recurrence and post-transplant survival.

RESULTS

Between groups, patients were comparable with regards to age and gender. In the radioembolization group, Milan criteria for HCC were met significantly less frequently (20.5% vs. 65.5%, p < 0.0001). Patients in the radioembolization group required significantly fewer intraarterial treatments (1 [1-2] vs. 1 [1-7], p = 0.0007). On explant specimen, tumor differentiation, microvascular invasion and tumor necrosis were comparable between the groups. HCC recurrence and overall survival were similar between the groups. Multivariable analysis detected increasing recipient age, male gender, complete tumor necrosis and absence of microvascular invasion being independently associated with decreased odds for HCC recurrence. Increasing model of end-stage liver disease (MELD) score and tumor recurrence were independently associated with increased odds of post-transplant death.

CONCLUSIONS

Intraarterial bridging treatment leading to tumor necrosis may not only prevent waitlist drop-out but also facilitate long-term successful liver transplantation in HCC patients. Both radioembolization and TACE represent potent treatment strategies.

Extrahepatic portosystemic shunts as an unusual but treatable cause of hyperammonemic encephalopathy in a noncirrhotic patient - a case report

We report a case of hyperammonemic encephalopathy due to extrahepatic portosystemic shunts in a noncirrhotic patient. A 79-year-old woman suffered from episodic confusion, disorientation, dysphasia and fluctuating level of consciousness. Electroencephalography (EEG) showed encephalopathic changes and serum levels of ammonia were elevated. Further investigation revealed mesenterorenal and mesenterocaval shunts, which had possibly evolved after pancreatic surgery 5 years ago. After shunt obliteration, the symptoms completely resolved, ammonia levels dropped to the normal range and EEG findings normalized. Clinicians should be aware of this rare but treatable cause of encephalopathy in noncirrhotic patients.

Radiation Dose Aspects of Hepatic Artery Infusion Chemotherapy in Uveal Melanoma Patients with Liver Metastases

Purpose

In uveal melanoma patients, liver metastases can be treated by hepatic artery infusion chemotherapy (HAIC). During this procedure, melphalan or, less frequently, fotemustine is infused into the hepatic artery or the hepatic lobe arteries in regularly repeated interventions to achieve local tumor control. The aim of this study was to investigate the radiation exposure of HAIC.

Material and methods

In this retrospective study, dose data from 841 procedures in 140 patients (mean age 65.3 ± 9.9 years, 74 female) who underwent HAIC between 06/2017 and 10/2021 at one of three different angiography systems were analyzed.

Results

In the overall population, dose area product (DAP) (median (IQR)) was 1773 cGy·cm² (884–3688). DAP was significantly higher in the first intervention, where a complete diagnostic workup of the vasculature was performed, than in follow-up interventions: 5765 cGy·cm² (3160–8804) versus 1502 cGy·cm² (807–2712) (p < 0.0001). DAP also increased significantly with the number of infusion positions (median, (IQR)): one position 1301 cGy·cm² (633–2717), two positions 1985 cGy·cm² (1118–4074), three positions 6407 cGy·cm² (2616–11590) (p < 0.0001).

Conclusion

In uveal melanoma patients with liver metastases undergoing HAIC, radiation exposure is significantly higher both at the first intervention compared to follow-up interventions, but also with increasing number of infusion positions.

Level of evidence: 3

ULTRA-LOW-DOSE COMPUTED TOMOGRAPHY IN UROLITHIASIS-EFFECT OF AN ADDITIONAL TIN FILTER ON IMAGE QUALITY AND RADIATION DOSE

To compare radiation dose and image quality of three CT-scanners using optimal dose protocols in patients with suspected urolithiasis regarding additional hardware (tin filter) and software (iterative reconstruction). Examinations from a single-source CT-scanner (A2) and a dual-source CT-scanner (DSCT) (A1) were compared to a tin filter DSCT (B) regarding dose-length product (DLP) and volume-weighted CT dose-index (CTDIvol). DLP of B was 51 and 53% lower in comparison to A1 and A2 (78.62, 159.20 and 165.80 mGy·cm, respectively; P < 0.0001). CTDIvol of B was 53% and 56% significantly lower compared to A1 and A2, respectively (1.52 vs. 3.22 vs. 3.46 mGy; P < 0.0001). Image quality in B proved to be similar to A1 and A2 (3.57, 3.51 and 3.60, respectively; P > 0.05). Inter-rater agreement regarding image quality was good for all CT-scanners (κ = 0.62). Modern CTs with a built-in tin filter allow a significant reduction of radiation exposure in patients with suspected urolithiasis by optimizing the X-ray spectrum.

European Multicenter Study on Degradable Starch Microsphere TACE: The Digestible Way to Conquer HCC in Patients with High Tumor Burden

To evaluate the safety and efficacy of transarterial chemoembolization with degradable starch microspheres (DSM-TACE) for the treatment of hepatocellular carcinoma (HCC) with a high tumor burden ineligible for or failing other palliative therapies, 121 patients from three European centers were included. Kaplan-Meier analysis was used for median overall survival (OS) and time to progression (TTP, mRECIST criteria) in months with a 95% confidence interval (95% CI). Uni- (UVA) and multivariate (MVA) analyses were performed using the Cox Proportional Hazard Model. The median OS of the study cohort was 15.5 (13.3-18.7) months. The UVA identified HCC lesions ≤10 cm, unilobar involvement, lower Child-Pugh class and Barcelona Clinic Liver Cancer (BCLC) stage, absence of vascular invasion, and extrahepatic metastases as factors for prolonged survival. MVA confirmed lesions of ≤10 cm and unilobar disease as independent OS factors. Median TTP was 9.5 (7.6-10.3) months. The best response was achieved after a median of 3 (range: 1-6) treatments with CR/PR/SD/PD in 13.5%/44.5%/25.2%/16.8%, respectively. DSM-TACE was well tolerated with no major clinical adverse events and only limited major laboratory events. Preserved liver function was observed after repetitive DSM-TACE treatments. Repetitive DSM-TACE is a safe, well-tolerated and effective treatment option for HCC patients with high tumor burden ineligible or failing other palliative therapies.

Lactate Dehydrogenase Prior to Transarterial Hepatic Chemoperfusion Predicts Survival and Time to Progression in Patients with Uveal Melanoma Liver Metastases

PURPOSE

 To assess serum lactate dehydrogenase (LDH) as a pretreatment prognostic factor in patients with uveal melanoma liver metastases treated with transarterial hepatic chemoperfusion (THC).

MATERIALS AND METHODS

 56 patients (48 % male, median age: 63.5 years) underwent a median of 4 THC sessions. Kaplan-Meier for median overall survival (OS) and time to hepatic progression (TTP; 95 %CI) in months and Cox proportional hazards model for uni- (UVA) & multivariate analyses (MVA) for hazard ratio (HR) evaluation were calculated.

RESULTS

 The median OS was 9.4 months. The pretreatment LDH value before 1st THC was the strongest OS predictor with 19.8 months for normal (≦ 280 units per liter (U/L)), 9.7 for intermediate (> 280-< 1000 U/L), and 3.84 months for high (≧ 1000 U/L) LDH. LDH significantly predicted a median TTP with 8 months, 4 months, and 1 month for normal, intermediate, and high LDH, respectively. UVA revealed intermediate (16.5) and high (77.3) LDH, bilirubin > the upper limit of normal (ULN) (2.89), alkaline phosphatase > 1.5 ULN (6.8), leukocytes > ULN (4.2), gamma-glutamyl transferase (GGT) > ULN (7), extrahepatic metastases (1.8) and liver lesions ≥ 5 cm (3.6) as significant predictors for worse OS. MVA confirmed intermediate (5) and high (27.1) LDH, bilirubin (5.7), GGT (2.9), and tumor size ≥ 5 cm (3.7) as significant independent predictors for worse OS. Patients with decreasing vs. increasing LDH > 10 % between 1st and 2nd THC (median: 38 days) survived longer (14.6 vs. 4.3 months) and progressed later (7 months vs. 1 month).

CONCLUSION

 Elevated pretreatment serum LDH is an essential and robust OS and TTP predictor, potentially allowing for the identification of patients benefiting most from transarterial hepatic chemoperfusion.

KEY POINTS

· Pretherapeutic LDH is the most reliable prognosticator for OS and TTP. · Therapy-related LDH decrease > 10 % between 1st and 2nd THC had prolonged OS and TTP. · Lower Values of LDH, bilirubin, gamma-glutamyl transferase, and tumor size are independent pretherapeutic predictors for longer OS. · Extrahepatic metastases do not have an independent influence on overall survival.

CITATION FORMAT

· Ludwig J, Haubold J, Heusner T et al. Lactate Dehydrogenase Prior to Transarterial Hepatic Chemoperfusion Predicts Survival and Time to Progression in Patients with Uveal Melanoma Liver Metastases. Fortschr Röntgenstr 2021; 193: 683 - 691.

Higher sensitivity for traumatic cerebral microbleeds at 7 T ultra-high field MRI: is it clinically significant for the acute state of the patients and later quality of life?

Background

The present study evaluates the possible prognostic benefits of 7 T susceptibility weighted imaging (SWI) of traumatic cerebral microbleeds (TMBs) over 3 T SWI to predict the acute clinical state and subjective impairments, including health-related quality of life (HRQOL), after closed head injury (CHI).

Methods

The study group comprised 10 participants with known TMBs All subjects underwent 3 T magnetic resonance imaging (MRI) and 7 T MRI, respectively. Location and count of TMBs were independently evaluated by two neuroradiologists. The initial Glasgow Coma Scale (GCS), the duration of coma and further clinical data were taken from the patients records. HRQOL was assessed by means of a questionnaire. Memory complaints and neurological symptoms were inquired at the time of the MRI examinations.

Results

SWI revealed a total of 485 TMBs at 3 T, 584 TMBs at 7 T with similar spatial resolution, and 684 TMBs at 7 T with a factor of 10 higher spatial resolution. The TMBs depicted by 7 T high-resolution SWI were correlated with the duration of coma (Spearman's rho of 0.77). The corresponding association with TMBs in 3 T MRI SWI showed a Spearman's rho of 0.71. The initial GCS score and TMBs correlated with a Spearman's rho of -0.35 at 3 T SWI MRI and a rho of -0.33 at 7 T high-resolution SWI, respectively. The physical aspect of HRQOL correlated substantially with the count of TMBs (rho = 0.44 for 3 T SWI and rho = 0.35 for both 7 T SWI sequences, respectively).

Conclusions

The number of TMBs showed a substantial association with indicators of the acute clinical state and chronic neurobehavioral parameters after CHI, but there was no additional advantage of 7 T MRI. These preliminary findings warrant a larger prospective study for the future.

Comparison of acceptance of PET/MR enterography and ileocolonoscopy in patients with inflammatory bowel diseases

OBJECTIVES

The aim of this study was to compare PET/MR enterography with ileocolonoscopy regarding patients' acceptance and their future preference.

METHODS

Between October 2014 and February 2018 one-hundred-eleven patients underwent PET/MR enterography and ileocolonoscopy within 2 weeks. Overall acceptance of each modality was rated using a 10-point Likert scale with higher score indicating worse experience. Wilcoxon test was used to assess difference. Patients' acceptance of bowel cleansing and oral intake of contrast agent was analyzed in the same way. Furthermore, to find out if diagnosis, gender and age might influence patients' acceptance and future preference, Mann-Whitney U test for ordinal and Chi-squared test for categorical parameters were applied.

RESULTS

77 patients (47 females) with a mean age of 44.5 years and diagnosed ulcerative colitis (UC; n = 46) and Crohn's disease (CD; n = 31), were included in the analysis. Overall, ileocolonoscopy was significantly better rated than PET/MR enterography (p < 0.001). Bowel cleansing was worse tolerated than oral intake of liquid (p < 0.001). Patients with CD preferred PET/MR enterography as future screening method, while UC patients favored ileocolonoscopy (p = 0.012). PET/MR enterography tended to be better accepted by CD patients (p = 0.08). Females tolerated both bowel cleansing and oral contrast agent worse than males (p = 0.05 and 0.047). No significant difference between different age groups was found.

CONCLUSIONS

Ileocolonoscopy was rated as better tolerable than PET/MR and the overall rate for future preference was very similar. Optimization of both modalities might enhance patients' acceptance.

7-T clinical MRI of the shoulder in patients with suspected lesions of the rotator cuff

Background

To evaluate feasibility and diagnostic performance of clinical 7-T magnetic resonance imaging (MRI) of the shoulder.

Methods

Eight patients with suspected lesions of the rotator cuff underwent 7-T MRI before arthroscopy. Image quality was scored for artifacts, B₁⁺ inhomogeneities, and assessability of anatomical structures. A structured radiological report was compared to arthroscopy. In four patients, a visual comparison with pre-existing 1.5-T examinations was performed.

Results

Regarding image quality, the majority of the sequences reached values above the middle of each scoring scale. Fat-saturated proton density sequences showed least artifacts and best structure assessability. The most homogenous B₁⁺ field was reached with gradient-echo sequences. Arthroscopy did not confirm tendinopathy/partial tear of supraspinatus in 5/8 patients, of subscapularis in 5/6, and of infraspinatus in one patient; only a partial lesion of the subscapularis tendon was missed. Pathologic findings of long bicipital tendon, acromioclavicular joint, glenohumeral cartilage, labrum, and subacromial subdeltoideal bursa were mainly confirmed; exceptions were one lesion of the long bicipital tendon, one subacromial bursitis, and one superior glenoid labrum anterior-to-posterior lesion, missed on 7-T MRI. Evaluating all structures together, sensitivity was 86%, and specificity 74%. A better contrast and higher image resolution was noted in comparison to previous 1.5-T examinations.

Conclusions

7-T MRI of the shoulder with diagnostic image quality is feasible. Overrating of tendon signal alterations was the main limitation. Although the diagnostic performance did not reach the current results of 3-T MRI, our study marks the way to implement clinical 7-T MRI of the shoulder.

Measuring the density of iodine depositions: Detecting an invisible residual tumor after conventional transarterial chemoembolization

Purpose

The purpose of this study is to evaluate the use of density measurements in the diagnosis of an underlying residual tumor beyond iodine depositions after Lipiodol-based conventional transarterial chemoembolization (cTACE).

Method and materials

Thirty follow-up CT scans of 20 patients 6–12 weeks after Lipiodol-based cTACE, receiving a digital subtraction angiography at the same time, were analyzed. Reference for the detection of a residual tumor was the angiography, and a visible contrast enhancement was categorized as a residual tumor (n = 16 with residual tumor; n = 14 without residual tumor). The density of the iodine depositions was measured in all containing slices in non-contrast-, arterial- and portal venous-phase CT scans, with a slice thickness of 5.00 mm. The mean density of the iodine deposition during the portal venous phase was subtracted from the mean density of the arterial phase to calculate the density changes (a positive enhancement score represents washout in the portal venous phase). In addition, a quotient relating to the non-contrast measurement was evaluated.

Results

Patients with a residual tumor displayed significantly higher enhancement scores in favor of density reduction between the arterial and portal venous phases, compared to patients without a residual tumor (1.41 ± 3.59, n = 14 vs. -13.97 ± 2.88, n = 16; p-value < 0.01). Furthermore, 87.75% of patients with an enhancement score higher than -1.00 (n = 9) had a residual tumor, whereas 100.00% of patients with an enhancement score lower than -20.00 (n = 6) were shown to be tumor-free. The enhancement score quotient resulted in similar findings.

Conclusion

After cTACE in patients with hepatocellular carcinoma (HCC), the presence of a viable tumor correlated with enhancement scores based on the density measurements of iodine depositions in different phases of the CT scan. Low enhancement scores were associated with completely treated tumors and can aid the decision process to avoid possibly unnecessary angiographies.

Computed tomography donor liver volumetry before liver transplantation in infants ≤10 kg: does the estimated graft diameter affect the outcome?

Aim of the study

Living donor liver transplantation (LDLT) is regularly performed in small-sized infants. Computed tomography (CT)-based donor liver volumetry is used to estimate the graft size. The aim of our study was to assess the results of CT liver volumetry and their impact on the clinical outcome after LDLT in extremely small-sized infants.

Patients and methods

In this study, we included all patients with a body weight of ≤10 kg who underwent living related liver transplantation at our centre between January 2004 and December 2014. In all cases of LDLT, a preoperative CT scan of the donor liver was performed, and the total liver and graft volumes were calculated. The graft shape was estimated by measuring the ventro-dorsal (thickness), cranio-caudal, and transversal (width) diameter of segment II/III. We assessed the impact of CT donor liver volumetry and other risk factors on the outcome, defined as patient and graft survival.

Results

In the study period, a total of 48 living related liver transplantations were performed at our centre in infants ≤10 kg [20 male (42%), 28 female (58%)]. The mean weight was 7.3 kg (range 4.4–10 kg). Among the recipients, 33 (69%) received primary abdominal closure and 15 (31%) had temporary abdominal closure. The patient and graft survival rates were 85% and 81%, respectively. In CT volumetry, the mean estimated graft volume was 255 mL (range 140–485 mL) and the actual measured mean graft weight was 307 g (range 127–463 g). The mean ventro-dorsal diameter of segment II/III was 6.9 cm (range 4.3–11.2 cm), the mean cranio-caudal diameter was 9 cm (range 5–14 cm), and the mean width was 10.5 cm (range 6–14.7 cm). The mean graft-body weight ratio (GBWR) was 4.38% (range 1.41–8.04%). A high graft weight, a GBWR >4%, and a large ventro-dorsal diameter of segment II/III were risk factors for poorer patient survival.

Conclusion

Preoperative assessment of the graft size is a crucial investigation before LDLT. For extremely small-sized recipients, not only the graft weight but also the graft shape seems to affect the outcome.

Liver maximum capacity (LiMAx) test as a helpful prognostic tool in acute liver failure with sepsis: a case report

Background

Acute liver failure (ALF) is a life-threatening entity particularly when infectious complications worsen the clinical course. Urgent liver transplantation (LT) is frequently the only curative treatment. However, in some cases, recovery is observed under conservative treatment. Therefore, prognostic tools for estimating course of the disease are of great clinical interest. Since laboratory parameters sometimes lack sensitivity and specificity, enzymatic liver function measured by liver maximum capacity (LiMAx) test may offer novel and valuable additional information in this setting.

Case presentation

We here report the case of a formerly healthy 20-year old male caucasian patient who was admitted to our clinic for ALF of unknown origin in December 2017. Laboratory parameters confirmed the diagnosis with an initial MELD score of 28 points. Likewise, enzymatic liver function was significantly impaired with a value of 147 [> 315] μg/h/kg. Clinical and biochemical analyses for viral-, autoimmune-, or drug-induced hepatitis were negative. Liver synthesis parameters further deteriorated reaching a MELD score of 40 points whilst clinical course was complicated by septic pneumonia leading to severe hepatic encephalopathy grade III-IV, finally resulting in mechanical ventilation of the patient. Interestingly, although clinical course and laboratory data suggested poor outcome, serial LiMAx test revealed improvement of the enzymatic liver function at this time point increasing to 169 μg/h/kg. Clinical condition and laboratory data slowly improved likewise, however with significant time delay of 11 days. Finally, the patient could be dismissed from our clinic after 37 days.

Conclusion

Estimating prognosis in patients with ALF is challenging by use of the established scores. In our case, improvement of enzymatic liver function measured by the LiMAx test was the first parameter predicting beneficial outcome in a patient with ALF complicated by sepsis.

Transjugular Intrahepatic Portosystemic Shunt in Patients with Portal Hypertension: Patency Depends on Coverage and Interventionalist's Experience

BACKGROUND AND AIMS

Transjugular intrahepatic portosystemic shunt (TIPS) is the treatment of choice in decompensated portal hypertension. TIPS revision due to thrombosis or stenosis increases morbidity and mortality. Our aim was to investigate patient- and procedure-associated risk factors for TIPS-revision.

PATIENTS AND METHODS

We retrospectively evaluated 189 patients who underwent the TIPS procedure. Only patients who required TIPS revision within 1 year (Group I, 34 patients) and patients who did not require re-intervention within the first year (Group II [control group], 54 patients) were included.

RESULTS

Out of 88 patients, the majority were male (69.3%) and mean age was 56 ± 11 years. Indications for TIPS were refractory ascites (68%), bleeding (24%), and Budd-Chiari syndrome (8%). The most frequent liver disease was alcohol-induced cirrhosis (60%). Forty-three patients (49%) received bare and 45 patients (51%) covered stents, thus resulting in reduction of hepatic venous pressure gradient (HVPG) from 19.0 to 9.0 mm Hg. When comparing patient- and procedure-related factors, the type of stent (p < 0.01) and interventionalist's experience (number of performed TIPS implantations per year; p < 0.05) were the only factors affecting the risk of re-intervention due to stent dysfunction, while age, gender, indication, Child-Pugh, and model of end-stage liver disease score, platelet count, pre- and post-HVPG, additional variceal embolization, stent diameter, and number of stents did not significantly differ.

CONCLUSION

Patients undergoing TIPS procedure should be surveilled closely for shunt dysfunction while covered stents and high-level experience are associated with increased -patency.

Spleen stiffness is positively correlated with HVPG and decreases significantly after TIPS implantation

BACKGROUND

Transjugular intrahepatic portosystemic shunt (TIPS) is indicated in patients with decompensated portal hypertension (PH). Hepatic venous pressure gradient (HVPG) is considered gold standard for assessment of PH. Because HVPG measurement is invasive, non-invasive methods for evaluating severity of PH are warranted.

PATIENTS AND METHODS

We retrospectively correlated spleen stiffness as measured by FibroScan with HVPG in patients who underwent TIPS. Twenty-four patients with spleen stiffness measurement (SSM) one day before (D-1), one day after (D+1) and 28 days after TIPS (D+28) were included.

RESULTS

SSM was positively correlated with pre-TIPS HVPG (HVPG <13mmHg, median SSM: 19.7±8.6kPa; HVPG 13-24mmHg, median SSM: 45.0±15.7kPa; HVPG >24mmHg, median SSM: 75.0±6.2kPa; p<0.05]; r²=0.72; p<0.001) and decreased significantly after TIPS implantation (D-1, median SSM: 67.1±17.3kPa; D+1, median SSM: 44.7±18.5kPa; D+28, median SSM: 35.6±17.0kPa; p<0.05), while liver stiffness measurement decrease was not statistically significant.

CONCLUSIONS

Our study highlights the utility of SSM as non-invasive tool in patients with chronic liver disease in evaluating degree of PH potentially offering a confirmable additional parameter in surveillance of patients undergoing TIPS procedure.

An 8-channel transceiver 7-channel receive RF coil setup for high SNR ultrahigh-field MRI of the shoulder at 7T

PURPOSE

In this work, we present an 8-channel transceiver (Tx/Rx) 7-channel receive (Rx) radiofrequency (RF) coil setup for 7 T ultrahigh-field MR imaging of the shoulder.

METHODS

A C-shaped 8-channel Tx/Rx coil was combined with an anatomically close-fitting 7-channel Rx-only coil. The safety and performance parameters of this coil setup were evaluated on the bench and in phantom experiments. The 7 T MR imaging performance of the shoulder RF coil setup was evaluated in in vivo measurements using a 3D DESS, a 2D PD-weighted TSE sequence, and safety supervision based on virtual observation points.

RESULTS

Distinct SNR gain and acceleration capabilities provided by the additional 7-channel Rx-only coil were demonstrated in phantom and in vivo measurements. The power efficiency indicated good performance of each channel and a maximum B₁⁺ of 19 μT if the hardware RF power limits of the MR system were exploited. MR imaging of the shoulder was demonstrated with clinically excellent image quality and submillimeter spatial resolution.

CONCLUSIONS

The presented 8-channel transceiver 7-channel receive RF coil setup was successfully applied for in vivo 7 T MRI of the shoulder providing a clear SNR gain vs the transceiver array without the additional receive array. Homogeneous images across the shoulder region were obtained using 8-channel subject-specific phase-only RF shimming.

Hepatic artery and biliary complications in liver transplant recipients with radioembolization bridging treatment for hepatocellular carcinoma

BACKGROUND

Locoregional bridging treatments are commonly applied in patients with hepatocellular carcinoma (HCC) prior to liver transplantation to prevent tumor progression during waiting time. It remains unknown whether pre-transplant radioembolization treatment may increase the prevalence of hepatic artery and biliary complications post-transplant.

METHODS

We performed a retrospective review of 173 consecutive patients with HCC who underwent liver transplantation at our transplant center between January 2007 and December 2016.

RESULTS

Radioembolization bridging treatment was applied in 42 patients while 131 patients received other or no forms of bridging treatment. The overall prevalence of intra-operative and early post-operative hepatic artery complications was 9.5% in the radioembolization group and 9.2% in the control group (P = 1.000). Biliary complications were significantly less frequent in the radioembolization group (4.8% vs 17.6%, P = .0442). In multivariable analysis, radioembolization was not significantly associated with an increased risk of arterial complications. Considering biliary complications, radioembolization bridging treatment was the only factor significantly associated with decreased odds (OR 0.187 (0.039, 0.892), P = .036).

CONCLUSIONS

Radioembolization is not associated with higher odds of hepatic artery complications following liver transplantation. There may even be a protective effect regarding biliary complications. Radioembolization as a bridge to transplantation may effectively be applied without compromising successful liver transplantation.

Partial spleen embolization reduces the risk of portal hypertension-induced upper gastrointestinal bleeding in patients not eligible for TIPS implantation

Introduction

Upper gastrointestinal bleeding (UGIB) is a severe and life-threatening complication among patients with portal hypertension (PH). Covered transjugular intrahepatic portosystemic shunt (TIPS) is the treatment of choice for patients with refractory or recurrent UGIB despite pharmacological and endoscopic therapy. In some patients, TIPS implantation is not possible due to co-morbidity or vascular disorders. Spleen embolization (SE) may be a promising alternative in this setting.

Materials and methods

We retrospectively analyzed 9 patients with PH-induced UGIB who underwent partial SE between 2012 and 2016. All patients met the following criteria: (i) upper gastrointestinal hemorrhage with primary or secondary failure of endoscopic interventions and (ii) TIPS implantation not possible. Each patient was followed for at least 6 months after embolization.

Results

Five patients (56%) suffered from cirrhotic PH, 4 patients (44%) from non-cirrhotic PH. UGIB occured in terms of refractory hemorrhage from gastric varices (3/9; 33%), hemorrhage from esophageal varices (3/9; 33%), and finally, hemorrhage from portal-hypertensive gastropathy (3/9; 33%). None of the patients treated with partial SE experienced re-bleeding episodes or required blood transfusions during a total follow-up time of 159 months, including both patients with cirrhotic- and non-cirrhotic PH.

Discussion

Partial SE, as a minimally invasive intervention with low procedure-associated complications, may be a valuable alternative for patients with recurrent PH-induced UGIB refractory to standard therapy.

Long-Term Outcome After Liver Transplantation for Hepatocellular Carcinoma Following Yttrium-90 Radioembolization Bridging Treatment

Background

Bridging treatments are employed in liver transplant waitlist patients with hepatocellular carcinoma (HCC) because of the risk of tumor progression during the waiting time. Radioembolization is mostly employed in the control of large or multifocal HCCs when other locoregional treatment modalities cannot be applied because of the number or size of lesions. The purpose of this study was to evaluate our experience with the use of radioembolization as a bridge to transplantation and its effect on tumor recurrence and survival after liver transplantation.

Material/Methods

A retrospective review of 40 consecutive patients with HCC who underwent liver transplantation after radioembolization bridging treatment between January 2007 and December 2015 at the University Hospital Essen, Germany, was performed. Patients’ characteristics, alpha-fetoprotein (AFP) levels, pathologic tumor response, tumor recurrence rate, and survival rates were examined through chart review.

Results

Histopathological examination of the explanted liver specimen revealed complete tumor necrosis in 17 specimens, partial necrosis in 18 specimens, and no significant necrosis in five specimens. Median overall survival was 46 months. Nine patients developed recurrent HCC. Median time from liver transplantation to diagnosis of tumor recurrence was 15 months. There was a trend towards a lower risk of tumor recurrence for patients with complete necrosis on explant specimens. Patients with tumor recurrence demonstrated statistically significantly higher pre- and post-treatment AFP levels (p=0.0234 and p=0.0236) and statistically significantly more frequently microvascular invasion (p=0.0163).

Conclusions

Histopathological assessment of explanted livers revealed at least partial necrosis in 87.5% of patients. Patients with successful bridging treatment, i.e. complete necrosis of explant specimens, demonstrate a trend towards a lower risk of tumor recurrence.

Multimodal therapy of recurrent and refractory bleeding from esophageal varices - case report and review of the literature

Bleeding from esophageal varices is a major cause of mortality in patients with advanced liver disease. Although standard treatment and secondary prophylaxis are effective, in some patients sustained hemostasis cannot be achieved. We report the case of a woman with alcoholic liver disease in whom pharmacological, endoscopic, and intravascular therapies failed to control variceal bleeding. Only a combination of (repeated) band ligation, insertion of a self-expanding metal stent, TIPS implantation and redilatation, transjugular variceal embolization, and finally implantation of a portocaval shunt proved to be successful. We discuss the stepwise approach to this situation and the challenges encountered in the process.

Rescue therapy of a refractory rectal variceal bleeding in a cirrhotic patient by Linton-Nachlas tube and TIPS implantation in combination with variceal embolization

Background Transjugular intrahepatic portosystemic shunt (TIPS) is considered the gold standard for treatment of gastrointestinal variceal bleeding refractory to endoscopic therapy in patients with portal hypertension. Clinically relevant hemorrhage from rectal varices is less frequent than from other sources, and the therapeutic role of TIPS is still ambiguous. Case report A 57-year-old female patient was referred to us in December 2015 with severe signs of decompensated alcohol-induced liver cirrhosis. During hospitalization, she presented with recurrent hematochezia from rectal varices following electrosurgical snare removal of a rectal adenoma. Endoscopic treatment with hemoclips, epinephrine and fibrin glue injections, and thermocoagulation failed to permanently stop the bleeding. Recurrent hemorrhage led to a further deterioration of liver function and clinical status of the patient. After a total of 3 endoscopic treatment attempts, hemostasis was achieved by transanal placement of a Linton-Nachlas balloon tube. Additionally, TIPS implantation with embolization of the rectal varices was performed successfully 24 hours after tube insertion, resulting in reduction of the portosystemic pressure gradient from 24 to 12 mmHg. Subsequently, the patient recovered clinically, hemopressin and catecholamine treatment was discontinued, and liver function test as well as serum hemoglobin levels improved. No further blood transfusions were required. Conclusion In this patient, rescue therapy with balloon compression and TIPS implantation in combination with variceal embolization in a cirrhotic patient with refractory rectal variceal bleeding was effective. To our knowledge, it is the first description of this specific therapeutic approach.

Novel implications in the treatment of hepatocellular carcinoma

Worldwide hepatocellular carcinoma remains one of the leading causes of cancer-related death, associated with a poor prognosis due to late diagnosis in the majority of cases. Physicians at care are frequently confronted with patients who are ineligible for curative treatment such as liver resection, transplantation or radiofrequency ablation. Besides established palliative locoregional therapies, such as ablation or chemoembolization, new treatment options, such as microwave ablation, drug-eluting bead transarterial chemoembolization or selective internal radiation therapy, are emerging; however, data from randomized controlled trials are still lacking. In order to achieve optimal tumor control, patients should receive tailored treatment concepts, considering their tumor burden, liver function and performance status, instead of strictly assigning patients to treatment modalities following algorithms that may be partly very restrictive. Palliative locoregional pretreatment might facilitate downstaging to ensure later curative resection or transplantation. In addition, the combined utilization of different locoregional treatment options or systemic co-treatment has been the subject of several trials. In cases where local tumor control cannot be achieved, or in the scenario of extrahepatic spread, sorafenib remains the only approved systemic therapy option. Alternative targeted therapies, such as immune checkpoint inhibitors have shown encouraging preliminary results, while data from phase III studies are pending.

Impact of dual-energy CT prior to radioembolization (RE)

BACKGROUND

Depiction of the exact arterial liver anatomy as well as identifying potential extrahepatic non-target vessels is crucial for a successful preparation of radioembolization (RE).

PURPOSE

To compare the diagnostic impact of dual-energy computed tomography (DECT) to digital subtraction angiography prior to RE.

MATERIAL AND METHODS

DECT was applied in 46 patients with hepatocellular carcinoma (HCC) prior to RE. Eighty kV DE as well as reconstructed 120 kV equivalent DE datasets were evaluated in comparison to correlating digital subtraction angiography (DSA) datasets. Two radiologists evaluated in consensus the delineation of liver arteries and extrahepatic non-target vessels utilizing a 4-point scale (4 = excellent delineation; 1 = non-diagnostic). In addition, the arterial vascularization of liver segment IV was evaluated and classified: signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR; liver arteries to adjacent liver tissue) were obtained via ROI analysis.

RESULTS

Both imaging techniques (DECT, DSA) enabled high-quality assessment of all analyzed liver arteries. Out of the two CT datasets, 80 kVp-DE datasets offered superior delineation of the right gastric artery (3.5 ± 0.7 vs. 2.5 ± 0.5), the vascularization of segment IV (3.9 ± 0.2 vs. 3.3 ± 0.5) as well as potential extrahepatic non-target vessels (3.9 ± 0.1 vs. 3.3 ± 0.5). In accordance to the results of the qualitative analysis, 80 kVp-DE datasets also yielded higher SNR (34.84 vs. 29.31) and CNR (28.29 vs. 21.8) values in comparison to the 120 kVp datasets.

CONCLUSION

Eighty kVp DECT enables a significantly better assessment of the arteries of the upper abdomen for therapy planning in comparison to correlating 120 kVp datasets. This may allow for identification of potential extrahepatic non-target vessels and assessment of target volume for therapy planning prior to DSA.

Aspects of postoperative magnetic resonance imaging of patients with avascular necrosis of the femoral head, treated by advanced core decompression

OBJECTIVE

To analyze remodeling processes after advanced core decompression (ACD) in patients with avascular femoral head necrosis by means of 3T MRI and to identify indicators for clinical outcome considering the defect size and characteristics of the bone graft and of the neighboring regeneration tissue.

MATERIALS AND METHODS

Thirty-four hips, with preexisting preoperative MRIs in 21 cases, were examined 1-34 months (mean 12.7) postoperatively by 3T MRI. The volume of necrosis was measured manually pre- and postoperatively to calculate absolute as well as percentage necrosis reduction. The signal intensity of the bone graft was quantified using a 4-point scale. Border phenomena between the bone graft and bone were described and classified into groups. Wilcoxon sign-rank test was used to identify correlations between the analyzed items and clinical signs of femoral head collapse after a mean follow-up time of 28.6 months (10.4-46.8).

RESULTS

Mean percentage reduction of necrosis was significantly higher in asymptomatic patients (59.36%) compared to patients with signs of femoral head collapse (28.78%, p = 0.008). Signal intensity of the bone graft increased in T1w and T2w TIRM sequences over time after surgery and was significantly higher in asymptomatic patients. Five border phenomena between the bone graft and healthy bone were identified. Among them, the so-called "rail sign" representing three layers of remodeling tissue correlated with the histological observations.

CONCLUSION

A variety of border phenomena representing remodeling processes have been described using 3T MRI. Beneath the percentage amount of necrosis reduction, we identified the signal intensity of the bone graft as an indicator for clinical outcome.

A single-center experience in radioembolization as salvage therapy of hepatic metastases of uveal melanoma

BACKGROUND

Overall survival (OS) of patients with hepatic metastases of uveal melanoma is strongly linked with hepatic tumor control. Due to the lack of an effective systemic chemotherapy, locoregional therapies like radioembolization should play an increasingly important role.

PURPOSE

To report complications and response rates of radioembolization as salvage therapy for hepatic uveal melanoma metastases.

MATERIAL AND METHODS

Between October 2006 and January 2014, eight patients (age, 59.1 ± 15.3 years; 5 men) with histologically proven uveal melanoma and hepatic metastases received radioembolization with glass microspheres at a single center. All patients had been heavily pretreated with multiple systemic/locoregional therapies resulting in a long median interval between diagnosis of hepatic metastases and radioembolization (17.1 months; range, 6.4-23.2 months). Follow-up consisted of clinical assessment, laboratory tests and tri-phasic computed tomography (CT) before and 1, 3, 6, 9, and 12 months after radioembolization. Response to therapy was evaluated by CT using RECIST version 1.1 and by survival time. Safety (laboratory and clinical toxicity) was rated according to Common Terminology Criteria for Adverse Events 4.03. Using Kaplan-Meier analysis time to progression of hepatic metastases (hTTP) and OS were calculated.

RESULTS

One month after radioembolization 50% of patients presented with stable and 50% with progressive disease. Median hTTP and OS after radioembolization were 4.3 weeks (range, 3.4-28.6 weeks) and 12.3 weeks (range, 3.7-62.6 weeks), respectively. Median OS after diagnosis of hepatic metastases was 19.9 months (range, 7.3-31.4 months). Radioembolization was tolerated well in all patients without toxicity higher than grade 2.

CONCLUSION

Radioembolization is a safe salvage therapy even in heavily pretreated hepatic metastases of uveal melanoma.

Diffuse axonal injury at ultra-high field MRI

Objective

Diffuse axonal injury (DAI) is a specific type of traumatic brain injury caused by shearing forces leading to widespread tearing of axons and small vessels. Traumatic microbleeds (TMBs) are regarded as a radiological marker for DAI. This study aims to compare DAI-associated TMBs at 3 Tesla (T) and 7 T susceptibility weighted imaging (SWI) to evaluate possible diagnostic benefits of ultra-high field (UHF) MRI.

Material and Methods

10 study participants (4 male, 6 female, age range 20-74 years) with known DAI were included. All MR exams were performed with a 3 T MR system (Magnetom Skyra) and a 7 T MR research system (Magnetom 7 T, Siemens AG, Healthcare Sector, Erlangen, Germany) each in combination with a 32-channel-receive coil. The average time interval between trauma and imaging was 22 months. Location and count of TMBs were independently evaluated by two neuroradiologists on 3 T and 7 T SWI images with similar and additionally increased spatial resolution at 7 T. Inter- and intraobserver reliability was assessed using the interclass correlation coefficient (ICC). Count and diameter of TMB were evaluated with Wilcoxon signed rank test.

Results

Susceptibility weighted imaging revealed a total of 485 TMBs (range 1-190, median 25) at 3 T, 584 TMBs (plus 20%, range 1-262, median 30.5) at 7 T with similar spatial resolution, and 684 TMBs (plus 41%, range 1-288, median 39.5) at 7 T with 10-times higher spatial resolution. Hemorrhagic DAI appeared significantly larger at 7 T compared to 3 T (p = 0.005). Inter- and intraobserver correlation regarding the counted TMB was high and almost equal 3 T and 7 T.

Conclusion

7 T SWI improves the depiction of small hemorrhagic DAI compared to 3 T and may be supplementary to lower field strengths for diagnostic in inconclusive or medicolegal cases.

3 Tesla high-resolution and delayed gadolinium enhanced MR imaging of cartilage (dGEMRIC) after autologous chondrocyte transplantation in the hip

BACKGROUND

To evaluate the feasibility of 3 Tesla (T) high-resolution and gadolinium enhanced MRI of cartilage (dGEMRIC) in the thin and rounded hip cartilage of patients after acetabular matrix-based autologous chondrocyte transplantation (MACT).

METHODS

Under general ethics approval, 24 patients were prospectively examined 6-31 months after acetabular MACT at 3T using high-resolution proton-density weighted (PDw) images (bilateral PD SPACE, 0.8 mm isotropic; unilateral PD-TSE coronal/sagittal, 0.8 × 0.8 resp. 0.5 × 0.5 × 2.5 mm) as well as T1 mapping (3D-FLASH, 0.78 mm isotropic) in dGEMRIC technique, and clinically scored. The cartilage transplant was evaluated using an adapted MOCART score (maximum 85 points). T1 relaxation times were measured independently by two radiologists. Here, regions of interest were placed manually in automatically calculated relaxation-maps, both in the transplant and adjacent healthy cartilage regions. Interobserver reliability was estimated by means of intraclass-correlation (ICC).

RESULTS

The transplant was morphologically definable in the PDw images of 23 patients with a mean MOCART score of 69 points (60-80 points, SD 6.5). T1 maps showed a clear differentiation between acetabular and femoral cartilage, but correlation with PDw images was necessary to identify the transplant. Mean T1 relaxation times of the transplant were 616.3 ms (observer 1) resp. 610.1 ms (observer 2), and of adjacent healthy acetabular cartilage 574.5 ms (observer 1) resp. 604.9 ms (observer 2). Interobserver reliability of the relaxation times in the transplant was excellent (ICC-coefficient 0.88) and in adjacent healthy regions good (0.77).

CONCLUSION

High-resolution PDw imaging with adapted MOCART scoring and dGEMRIC is feasible after MACT in the thin and rounded hip cartilage.

Vestibular effects of a 7 Tesla MRI examination compared to 1.5 T and 0 T in healthy volunteers

Ultra-high-field MRI (7 Tesla (T) and above) elicits more temporary side-effects compared to 1.5 T and 3 T, e.g. dizziness or “postural instability” even after exiting the scanner. The current study aims to assess quantitatively vestibular performance before and after exposure to different MRI scenarios at 7 T, 1.5 T and 0 T. Sway path and body axis rotation (Unterberger's stepping test) were quantitatively recorded in a total of 46 volunteers before, 2 minutes after, and 15 minutes after different exposure scenarios: 7 T head MRI (n = 27), 7 T no RF (n = 22), 7 T only B₀ (n = 20), 7 T in & out B₀ (n = 20), 1.5 T no RF (n = 20), 0 T (n = 15). All exposure scenarios lasted 30 minutes except for brief one minute exposure in 7 T in & out B₀. Both measures were documented utilizing a 3D ultrasound system. During sway path evaluation, the experiment was repeated with eyes both open and closed. Sway paths for all long-lasting 7 T scenarios (normal, no RF, only B₀) with eyes closed were significantly prolonged 2 minutes after exiting the scanner, normalizing after 15 minutes. Brief exposure to 7 T B₀ or 30 minutes exposure to 1.5 T or 0 T did not show significant changes. End positions after Unterberger's stepping test were significantly changed counter-clockwise after all 7 T scenarios, including the brief in & out B₀ exposure. Shorter exposure resulted in a smaller alteration angle. In contrast to sway path, reversal of changes in body axis rotation was incomplete after 15 minutes. 1.5 T caused no rotational changes. The results show that exposure to the 7 Tesla static magnetic field causes only a temporary dysfunction or “over-compensation” of the vestibular system not measurable at 1.5 or 0 Tesla. Radiofrequency fields, gradient switching, and orthostatic dysregulation do not seem to play a role.

Hepatic volume changes after lobar selective internal radiation therapy (SIRT) of hepatocellular carcinoma

AIM

To assess volume changes of treated and non-treated liver segments after selective internal radiation therapy (SIRT) in patients with hepatocellular carcinoma (HCC) and compromised hepatic function due to cirrhosis over a time course of 12 months after SIRT.

MATERIALS AND METHODS

All patients underwent SIRT of the right liver lobe with yttrium 90 (Y-90). Absolute volumes of the right liver lobe (RLV) and left liver lobe (LLV) were assessed using computed tomography (CT) before and 1, 3, 6, 9, and 12 months after SIRT. Changes at follow-up relative to baseline volumes were analysed ("normalized" volumes). Furthermore, the relative volume of the LLV [LLV/(RLV + LLV)] was calculated ("relative" volumes). For statistical analysis p < 0.05 was considered statistically significant.

RESULTS

Forty-five HCC patients (36 men, nine women, mean age 71.9 years, range 55-90 years) were studied. The mean baseline RLV and LLV reached 1116 ml [95% confidence intervals (CI): 1006-1226 ml] and 601 ml (95% CI: 514-688 ml), respectively. At 6 months following radioembolization, the LLV increased by 30.8% (RLV -33.9%), with the relative LLV increasing from 35% (pre-radioembolization) to 50.5%. RLV further decreased and LLV increased 12 months after SIRT (nRLV -44.9%, nLLV +40.1%, relative LLV 56.5%). All changes were significant.

CONCLUSION

Constraints of liver function after radioembolization of one liver lobe can be partially compensated through hypertrophy of the contralateral lobe. The rate of volumetric changes is the highest in the first 6 months following radioembolization. The present data can also be the basis to propagate radiation lobectomy for selected patients, simultaneously providing tumour control and future remnant liver hypertrophy before curative hemihepatectomy.

Memory-related hippocampal activity can be measured robustly using FMRI at 7 tesla

High field strength functional magnetic resonance imaging (fMRI) has developed rapidly. However, it suffers from increased artifacts in brain regions such as the medial temporal lobe (MTL), challenging functional imaging of the hippocampus with the objective of high-spatial resolution, which is particularly useful for this region both from a clinical and cognitive neuroscience perspective. We set out to compare a BOLD sequence at 7 T versus 3 T to visualize the MTL activity during an associative memory-encoding task. Twenty-eight healthy volunteers underwent a blocked-design fMRI at either 3 T or 7 T while performing a face-profession associative memory encoding task. Qualitative analyses of overall image quality revealed that functional images at 7 T were of high quality, showing a good white/gray matter contrast, with reasonably acceptable signal dropouts and artifacts at the lower portion of the temporal lobe. Analyses of task-related fMRI data revealed robust activations in the bilateral MTL during associative memory encoding at both field strengths. Notably, we observed significantly stronger memory-related hippocampal activation at 7 T than at 3 T, suggesting higher BOLD sensitivity at 7 T. These results are discussed in the light of the feasibility of 7 T scanning protocols for the MTL.

MRI of the ankle joint in healthy non-athletes and in marathon runners: image quality issues at 7.0 T compared to 1.5 T

OBJECTIVE

To present imaging characteristics of the ankle at 7.0 T and to investigate the appearance and image quality of presumed pathologies of ankles without physical strain as well as of ankles after a marathon run in comparison to 1.5 T.

MATERIALS AND METHODS

Appearance of presumed pathologic findings and image quality of TSE (PD, T2, and STIR) and GRE sequences (MEDIC, DESS, and/or CISS) at 7.0 T and 1.5 T MRI were compared by two senior radiologists in consensus in two healthy controls without strain and in six marathon runners after a full-length marathon (eight males, mean age 49.1 years).

RESULTS

Overall, 7.0 T MRI allowed for higher resolution images for most of the sequences while requiring comparable acquisition times and achieving high contrast images mainly in gradient echo sequences. Bursal or presumed peritendineal fluid and/or edematous tissue, which were found in seven of eight subjects, could be best appreciated with 7.0 T MEDIC. Other findings with sharper delineation at 7.0 T included cartilage defects (best: CISS), osseous avulsions, and osteophytes (best: DESS). Nevertheless, 1.5 T STIR imaging enabled assessment of a tibiotalar bone edema-like lesion in two runners, which was barely visible at 7.0 T using STIR, but not with any other sequence at 7.0 T including MEDIC (with frequency selective fat suppression). 7.0 T showed larger image quality variations with challenges especially in the TSE sequences.

CONCLUSION

Our initial results of ultra-high-field ankle joint imaging demonstrate the improved depiction of ankle anatomy, fluid depositions, and cartilage defects. However imaging of edema-like bone lesions remains challenging at ultra-high magnetic field strength, and TSE coverage in particular is limited by the specific absorption rate.

Selective internal radiation therapy of hepatocellular carcinoma: potential hepatopulmonary shunt reduction after sorafenib administration

Sorafenib, a protein kinase inhibitor, is a systemic drug that has been licensed for the treatment of hepatocellular carcinoma (HCC). This retrospective study assessed whether the administration of sorafenib can result in a reduction of the hepatopulmonary shunt (HPS) before selective internal radiation therapy (SIRT). After exclusion from SIRT because of high HPS, computed tomography scan indicated a shunt reduction in seven patients with HCC receiving sorafenib. Repeated measurements revealed HPS reduction (from 26.5% to 7.5% on average), and subsequent SIRT became possible. In conclusion, sorafenib may reduce HPS in patients with advanced HCC in some cases.

Selective internal radiotherapy (SIRT) of hepatic tumors: how to deal with the cystic artery

PURPOSE

Selective internal radiotherapy (SIRT) with the beta emitter yttrium-90 (Y90) is a rapidly developing therapy option for unresectable liver malignancies. Nontarget irradiation of the gallbladder is a complication of SIRT. Thus, we aimed to assess different strategies to avoid infusion of Y90 into the cystic artery (CA).

METHODS

After hepatic digital subtraction angiography and administration of technetium-99m-labeled human serum albumin ((99)mTc-HSA), 295 patients with primary or secondary liver tumors underwent single-photon emission computed tomography/computed tomography (SPECT/CT). Different measures were taken before repeated Y90 mapping and SIRT to avoid unintended influx into the CA where necessary. Clinical symptoms, including pain, fever, or a positive Murphy sign, were assessed during patient follow-up.

RESULTS

A significant (99)mTc-HSA accumulation in the gallbladder wall (higher (99)mTc-HSA uptake than in normal liver tissue) was seen in 20 patients. The following measures were taken to avoid unintended influx into the CA: temporary/permanent occlusion of the CA with gelfoam (n = 5)/microcoil (n = 1), induction of vasospasm with a microwire (n = 4), or altering catheter position (n = 10). Clinical signs of cholecystitis were observed in only one patient after temporary CA occlusion with gelfoam and were successfully treated by antibiotics. Cholecystectomy was not required for any patient.

CONCLUSION

It is important to identify possible nontarget irradiation of the gallbladder. The risk for radiation-induced cholecystitis can be easily minimized by temporary or permanent CA embolization, vasospasm induction, or altering the catheter position.