Vibration Controlled Transient Elastography to Evaluate Steatosis in Candidate Living Donors for Liver Transplantation

BACKGROUND

The ability of vibration controlled transient elastography (VCTE) to reliably exclude significant steatosis in living donor candidates could obviate the need for invasive liver biopsies, expedite the donor approval process, and reduce recipient wait time. We therefore aimed to determine whether VCTE controlled attenuation parameter (CAP) could be used to detect steatosis in potential living donors.

METHODS

Living donor candidates who presented for evaluation between 2016 and 2019 underwent standard donor workup, VCTE, and liver biopsy if indicated. CAP scores were compared with MRI-Fat Fraction and, when available, histologic fat fraction from liver biopsy. Receiver operating characteristic curves were used to identify cutoffs with appropriate sensitivity and specificity for screening. Statistical analysis was conducted using R (version 3.6.0).

RESULTS

Seventy-nine candidate living donors presented during the study period, of whom 71 were included in the final analysis and of whom 20 underwent liver biopsy. There was a positive correlation between MRI-Fat Fraction and CAP scores with an observed Spearman correlation coefficient of 0.424 ( P < 0.01). A CAP score of 271.5 dB/m or less was determined to have 89.8% sensitivity and 75% specificity for detecting <5% steatosis on MRI. The correlation between CAP and steatosis of available histologic samples had a Pearson correlation coefficient of 0.603 ( P = 0.005). A CAP cutoff of 276.0 dB/m demonstrated 66.7% sensitivity and 85.7% specificity for detecting <15% histopathologic steatosis and positive and negative predictive values of 71.5% and 82.7%, respectively.

CONCLUSIONS

VCTE can be integrated into living donor evaluation to accurately screen for hepatic steatosis.

Hepatocellular carcinoma in patients cured of chronic hepatitis C: Minimal steatosis

BACKGROUND

Successful treatment of hepatitis C reduces liver inflammation and fibrosis; however, patients remain at risk of developing hepatocellular carcinoma (HCC).

AIMS

To identify risk factors for new-onset HCC in patients cured of hepatitis C.

METHODS

Imaging, histological, and clinical data on patients whose first HCC was diagnosed >12 months of post-SVR were analyzed. Histology of 20 nontumor tissues was analyzed in a blinded manner using the Knodel/Ishak/HAI system for necroinflammation and fibrosis/cirrhosis stage and the Brunt system for steatosis/steatohepatitis. Factors associated with post-SVR HCC were identified by comparison with HALT-C participants who did not develop post-SVR HCC.

RESULTS

Hepatocellular carcinoma was diagnosed in 54 patients (45 M/9F), a median of 6 years of post-SVR [interquartile range (IQR) =1.4-10y] at a median age of 61 years (IQR, 59-67). Approximately one-third lacked cirrhosis, and only 11% had steatosis on imaging. The majority (60%) had no steatosis/steatohepatitis in histopathology. The median HAI score was 3 (1.25-4), indicating mild necroinflammation. In a multivariable logistic regression model, post-SVR HCC was positively associated with non-Caucasian race (p = 0.03), smoking (p = 0.03), age > 60 years at HCC diagnosis (p = 0.03), albumin<3.5 g/dL (p = 0.02), AST/ALT>1 (p = 0.05), and platelets <100 × 103 cells/μL (p < 0.001). Alpha fetoprotein ≥4.75 ng/mL had 90% specificity and 71% sensitivity for HCC occurrence. Noncirrhotic patients had larger tumors (p = 0.002) and a higher prevalence of vascular invasion (p = 0.016) than cirrhotic patients.

CONCLUSIONS

One-third of patients with post-SVR HCC did not have liver cirrhosis; most had no steatosis/steatohepatitis. Hepatocellular carcinomas were more advanced in noncirrhotic patients. Results support AFP as a promising marker of post-SVR HCC risk.

Impact of mandated prospectively reported apparent diffusion coefficient values on the rates of positivity for clinically significant prostate cancer by PI-RADS score

BACKGROUND

Prior research has shown that retrospectively measured apparent diffusion coefficient (ADC) of prostate magnetic resonance imaging (MRI) lesions is associated with clinically significant prostate cancer (csPCa) on targeted biopsy suggesting that ADC should be measured and reported prospectively.

PURPOSE

To assess the impact of mandatory prospective measurement of ADC on the rates of positivity across PI-RADS scores for csPCa.

MATERIAL AND METHODS

Consecutive patients who underwent ultrasound (US)-MRI fusion prostate biopsy from August 2018 to July 2019 and who had prospectively reported ADC were compared to control patients who did not. Rates of positivity by PI-RADS category were computed and compared using Chi-square. Multivariable regression was performed.

RESULTS

In total, 126 patients (median age 65 years) with 165 prostate lesions (19, 51, 70, and 25 PI-RADS 2, 3, 4, and 5, respectively) and prospectively reported ADC values were compared to 113 control patients (median age 66 years) with 157 prostate lesions (17, 42, 64, and 34 PI-RADS 2, 3, 4, and 5, respectively). Rates of positivity across PI-RADS scores were similar between the two cohorts; 11%, 25%, 55%, and 76% and 0%, 21%, 56%, and 62% for PI-RADS 2, 3, 4, and 5 in the test and control cohorts, respectively (Chi-square P = 0.78). Multivariate logistic regression showed no significant association between the presence of prospectively measured ADC and csPCa (odds ratio 1.1, 95% confidence interval 0.7-1.7, P = 0.82).

CONCLUSION

Prospective ADC measurement may not impact PI-RADS category assignments or positivity rates for csPCa under current guidelines. Future versions of PI-RADS may need to incorporate ADC into scoring rules to realize their potential.

Student-Authored Autopsy Reports of Anatomical Donors: Their First Patients

The preparation of student-authored autopsy reports of anatomical donors was added to the Gross Anatomy course to integrate the basic and clinical sciences and determine whether students considered this early clinical exposure to be a valuable experience. All donors were scanned using computerized tomography (CT) and student groups received the scan of their donor and a report written by a radiologist. As students dissected, they took photographs and biopsies of pathological findings that were processed for microscopic evaluation. Following consultation with pathologists and radiologists, each group prepared an autopsy report that proposed a cause of death supported with macroscopic, microscopic, and CT images. Cardiovascular events and cancer were the most common. Autopsy reports were evaluated by the faculty and each student group received feedback with respect to content, accuracy, and completeness and whether faculty agreed with students' proposed cause of death. A majority of students answering an anonymous survey indicated that this exercise was valuable or somewhat valuable, but did not agree that preparation of the autopsy report resulted in their being more engaged during the course. Students agreed or somewhat agreed that the exercise should be repeated next year, that they gained insight into the clinical manifestations of disease, that they were able to interpret the CT scan themselves, that meeting with a pathologist was interesting, and that the time required to prepare the report was adequate. Since autopsy reports prepared by students are feasible and students found it to be a valuable experience, we suggest that medical schools add this to Gross Anatomy courses to introduce clinical material and increase clinical relevance.

Radiomics of MRI for pretreatment prediction of pathologic complete response, tumor regression grade, and neoadjuvant rectal score in patients with locally advanced rectal cancer undergoing neoadjuvant chemoradiation: an international multicenter study

OBJECTIVE

To investigate whether pretreatment MRI-based radiomics of locally advanced rectal cancer (LARC) and/or the surrounding mesorectal compartment (MC) can predict pathologic complete response (pCR), neoadjuvant rectal (NAR) score, and tumor regression grade (TRG).

METHODS

One hundred thirty-two consecutive patients with LARC who underwent neoadjuvant chemoradiation and total mesorectal excision (TME) were retrospectively collected from 2 centers in the USA and Italy. The primary tumor and surrounding MC were segmented on the best available T2-weighted sequence (axial, coronal, or sagittal). Three thousand one hundred ninety radiomic features were extracted using a python package. The most salient radiomic features as well as MRI parameter and clinical-based features were selected using recursive feature elimination. A logistic regression classifier was built to distinguish between any 2 binned categories in the considered endpoints: pCR, NAR, and TRG. Repeated k-fold validation was performed and AUCs calculated.

RESULTS

There were 24, 87, and 21 T4, T3, and T2 LARCs, respectively (median age 63 years, 32 to 86). For NAR and TRG, the best classification performance was obtained using both the tumor and MC segmentations. The AUCs for classifying NAR 0 versus 2, pCR, and TRG 0/1 versus 2/3 were 0.66 (95% CI, 0.60-0.71), 0.80 (95% CI, 0.74-0.85), and 0.80 (95% CI, 0.77-0.82), respectively.

CONCLUSION

Radiomics of pretreatment MRIs can predict pCR, TRG, and NAR score in patients with LARC undergoing neoadjuvant treatment and TME with moderate accuracy despite extremely heterogenous image data. Both the tumor and MC contain important prognostic information.

KEY POINTS

• Machine learning of rectal cancer on images from the pretreatment MRI can predict important patient outcomes with moderate accuracy. • The tumor and the tissue around it both contain important prognostic information.

Nivolumab for hepatocellular carcinoma (HCC) in a real-world context

e15675

Background: Novel immunotherapies may be effective in patients with HCC; however, patients with advanced liver disease are often excluded from clinical trials. The goal of our study was to evaluate the safety and efficacy of nivolumab for HCC in a real-world context, including among patients with advanced liver disease. Methods: We examined all cases of HCC initiated on off-study nivolumab alone or in combination with locoregional therapy at our institution from 2/2017 to 7/2018. Our sample included 14 patients. We report participant demographics, baseline liver function, treatment toxicity, and overall survival (OS). Results: The majority of participants were male (71%) and Caucasian (57%). NAFLD (36%) and HCV (43%) were the most frequently cited risk factors for HCC. Patients had variable liver disease at baseline, with 36% Child-Turcotte-Pugh (CTP) A, 36% CTP B, and 21% CTP C disease. Patients received either nivolumab only (50%), or nivolumab with locoregional therapy (LRT) (50%). All patients with CTP C disease received nivolumab alone. Treatment was generally safe, with only grade 1 or 2 toxicities reported, most commonly fatigue. Median OS was 7 months. Of note, one patient with baseline CTP C disease showed complete response to nivolumab treatment but experienced recurrence off nivolumab. Conclusions: Our study is the first to report the use of nivolumab in patients with HCC and CTP C disease. Nivolumab was well-tolerated in a real-world context in this small patient cohort, including among patients with advanced cirrhosis. Further study in larger patient populations is warranted. [Table: see text]

Validation of Liver Imaging Reporting and Data System 2017 (LI-RADS) Criteria for Imaging Diagnosis of Hepatocellular Carcinoma

BACKGROUND

The Liver Imaging Reporting and Data System (LI-RADS) is being adapted by many clinical practices. To support continuation of its use, LI-RADS (LR) is in need of multicenter validation studies of recent LI-RADS iterations. Furthermore, while both gadoxetate and extracellular agents have been incorporated into LI-RADS, comparison of the diagnostic performance between the two has yet to be determined.

PURPOSE/HYPOTHESIS

To evaluate the rate, diagnostic performance, and interreader reliability (IRR) of LI-RADS 2017 for hepatocellular carcinoma, including LR major and ancillary features, with both gadoxetate and extracellular agent-enhanced MRI against a reference standard of histopathology or imaging follow-up.

STUDY TYPE

Retrospective.

POPULATION

In all, 114 patients with 144 observations were included who met LR 2017 criteria for at risk and had at least one hepatic observation on liver MRI performed with either gadoxetate (n = 52) or an extracellular agent (n = 92) between 2010-2016, with histopathology (n = 103) or follow-up imaging (n = 41).

FIELD STRENGTH/SEQUENCE

1.5 and 3.0T/T₁ -T₂ WI, diffusion-weighted imaging.

ASSESSMENT

Three radiologists independently assessed major/ancillary features and assigned overall LI-RADS category for every observation.

STATISTICAL TESTS

Diagnostic performance of LR5/TIV+LR5 for identifying hepatocellular carcinoma (HCC) was compared between contrast agents with a generalized estimating equation. Weighted kappa was performed for interrater reliability.

RESULTS

The frequency of HCCs among LR1, LR2, LR3, L4, LR5, LRTIV+LR5, and LRM observations were: 0% (all readers), 0-12.5%, 11.4-26.9%, 50-76%, 83.0-95.1%, 83.3-100.0%, and 45.0-65.0%, respectively. Sensitivity of LR5/LRTIV+LR5 for HCC was 59.7-71.4% and specificity 85.0-96.8%. LI-RADS specificity and positive predictive value for observations imaged with gadoxetate was higher than extracellular agent for the most inexperienced reader (R3) (P = 0.009-0.034). IRR for LI-RADS categorization was substantial (k = 0.661).

DATA CONCLUSION

Increasing numerical LI-RADS 2017 categories demonstrate a greater percentage of HCCs. LR5/TIV+LR5 demonstrates excellent specificity and fair sensitivity for HCC. MRI with gadoxetate in liver transplant candidates may be beneficial for less experienced readers, although further large-scale prospective studies are needed.

LEVEL OF EVIDENCE

4 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2019;49:e205-e215.

Mitochondrial diseases: an overview of genetics, pathogenesis, clinical features and an approach to diagnosis and treatment

Defects in structures or functions of mitochondria, mainly involving the oxidative phosphorylation, mitochondrial biogenesis and other metabolic pathways have been shown to be associated with a wide spectrum of clinical phenotypes. The ubiquitous nature of mitochondria and their unique genetic features contribute to the clinical, biochemical and genetic heterogenecity of mitochondrial diseases. This article focuses on the recent advances in the field of mitochondrial disorders with respect to the consequences for an advanced clinical and genetic diagnostics. In addition, an overview on recently identified genetic defects and their pathogenic molecular mechanisms are given.

Ischemic colitis

Fifteen patients with ischemic colitis were treated; in every case the diagnosis was made at operation or autopsy. Abdominal pain, tenderness, and distention were the most common findings. Five patients had the transient form of the disease, two stricturing, and eight gangrenous. Five patients were operated upon, two because of stricturing disease, three because of gangrene of the colon. Both of the former patients survived, one of the latter. Diagnosis of transient ischemic colitis can be made by barium enema studies. This form of the disease is self-limiting and recovery should be expected. Stricturing ischemic colitis may be diagnosed by barium enema, but doubtful cases will require laparotomy and resection. It is difficult, if not impossible, to differentiate the gangrenous form of the disease from other abdominal catastrophes without operation. When the condition is found at celiotomy, bowel resection without anastomosis is recommended.