Ultrasound-based steatosis grading system using 2D-attenuation imaging: An individual patient data meta-analysis with external validation.

BACKGROUND AND AIMS: Noninvasive tools assessing steatosis, such as ultrasonography-based 2D-attenuation imaging (ATI), are needed to tackle the worldwide burden of steatotic liver disease. This one-stage individual patient data (IPD) meta-analysis aimed to create an ATI-based steatosis grading system. APPROACH AND RESULTS: A systematic review (EMBASE + MEDLINE, 2018-2022) identified studies, including patients with histologically or magnetic resonance imaging proton-density fat fraction (MRI-PDFF)-verified ATI for grading steatosis (S0 to S3). One-stage IPD meta-analyses were conducted using generalized mixed models with a random study-specific intercept. Created ATI-based steatosis grading system (aS0 to aS3) was externally validated on a prospective cohort of patients with type 2 diabetes and metabolic dysfunction-associated steatotic liver disease (n=174, histologically and MRI-PDFF-verified steatosis). Eleven enrolled studies included 1374 patients, classified into S0, S1, S2, and S3 in 45.4%, 35.0%, 9.3%, and 10.3% of the cases. ATI was correlated with histological steatosis ( r = 0.60; 95% CI: 0.52, 0.67; p < 0.001) and MRI-PDFF ( r = 0.70; 95% CI: 0.66, 0.73; p < 0.001) but not with liver stiffness ( r = 0.03; 95% CI: -0.04, 0.11, p = 0.343). Steatosis grade was an independent factor associated with ATI (coefficient: 0.24; 95% CI: [0.22, 0.26]; p < 0.001). ATI marginal means within S0, S1, S2, and S3 subpopulations were 0.59 (95% CI: [0.58, 0.61]), 0.69 (95% CI [0.67, 0.71]), 0.78 (95% CI: [0.76, 0.81]), and 0.85 (95% CI: [0.83, 0.88]) dB/cm/MHz; all contrasts between grades were significant ( p < 0.0001). Three ATI thresholds were calibrated to create a new ATI-based steatosis grading system (aS0 to aS3, cutoffs: 0.66, 0.73, and 0.81 dB/cm/MHz). Its external validation showed Obuchowski measures of 0.84 ± 0.02 and 0.82 ± 0.02 with histologically based and MRI-PDFF-based references. CONCLUSIONS: ATI is a reliable, noninvasive marker of steatosis. This validated ATI-based steatosis grading system could be valuable in assessing patients with metabolic dysfunction-associated steatotic liver disease.

Two-dimensional Shear-Wave Elastography and US Attenuation Imaging for Nonalcoholic Steatohepatitis Diagnosis: A Cross-sectional, Multicenter Study.

Background Multiparametric US examination may have potential in the comprehensive evaluation of nonalcoholic fatty liver disease (NAFLD), but multicenter studies are lacking. Purpose To evaluate the diagnostic performance of multiparametric US with the attenuation coefficient (AC) from attenuation imaging (ATI) and liver stiffness (LS) and dispersion slope (DS) from two-dimensional (2D) shear-wave elastography (SWE) in a multicenter study of patients with NAFLD. Materials and Methods This prospective study enrolled consecutive participants between December 2019 and June 2021 with suspected nonalcoholic steatohepatitis (NASH) who were scheduled to undergo liver biopsy in five tertiary hospitals. Before the procedure, all participants underwent US with ATI and 2D SWE according to the study protocol. Multivariable linear regression analyses were performed to determine the significant determinant factors for AC, LS, and DS. Diagnostic performance was decided based on the areas under the receiver operating characteristic curve (AUCs). Results A total of 132 participants (median age, 38 years; IQR, 27-54 years; 69 women) were evaluated. Among the participant characteristics, including pathologic findings, demographic characteristics, body mass index, and serum markers, hepatic steatosis for AC (P < .001), lobular inflammatory activity for DS (P = .007), and both fibrosis (P = .01) and lobular inflammatory activity (P = .04) for LS were significant determinant factors. At histopathologic examination, 53 of the 132 participants (40.2%) had NASH. The risk score system obtained using unweighted sum of scores from AC and DS showed the best diagnostic performance in the detection of NASH (AUC = 0.94; 95% CI: 0.89, 0.98; P < .05 for all), as compared with serum markers or other US parameters alone (AUC ≤ 0.88). Conclusion US attenuation imaging and two-dimensional shear-wave elastography were useful for assessing hepatic steatosis, lobular inflammation, and fibrosis. The risk score system obtained using the attenuation coefficient and dispersion slope showed the best diagnostic performance fo r nonalcoholic steatohepatitis. cris.nih.go.kr no. KCT0004326 © RSNA, 2022 Online supplemental material is available for this article.

Noncirrhotic Portal Hypertension after Trastuzumab Emtansine in HER2-positive Breast Cancer as Determined by Deep Learning-measured Spleen Volume at CT.

Background Trastuzumab emtansine (T-DM1) is an antibody-drug conjugate approved for use in human epidermal growth factor receptor 2 (HER2)-positive breast cancer. Case reports have suggested an association between T-DM1 and portal hypertension. Purpose To evaluate the association of T-DM1 therapy with spleen volume changes and portal hypertension on CT scans and clinical findings compared with lapatinib and capecitabine therapy. Materials and Methods Patients with HER2-positive breast cancer who were administered at least two cycles of T-DM1 or lapatinib and capecitabine (controls) in a tertiary institution from 2001 to 2020 and who underwent CT before initial treatment and at least once during treatment were retrospectively enrolled. Spleen volume changes and the signs of portal hypertension (gastroesophageal varix [GEV], spontaneous portosystemic shunt [SPSS], and ascites) were evaluated at contrast-enhanced CT. Patients were followed until treatment ended or for 2 years after the start of treatment. Spleen volume changes were measured with a deep learning algorithm and evaluated by using a linear mixed model. The incidences of splenomegaly and portal hypertension were compared between the T-DM1 and control groups by using a χ2 test or Fisher exact test. Results The T-DM1 group included 111 patients (mean age, 54 years ± 11 [SD]; 111 women) and the control group included 122 patients (mean age, 50 years ± 9; 121 women). Spleen volume progressively increased with T-DM1 therapy but was constant in the control group (104% ± 5 vs -1% ± 6 at the 33rd treatment cycle, respectively; P < .001). Incidences of splenomegaly (46% [51 of 111] vs 3% [four of 122] of patients; P < .001), GEV (11% [12 of 111] vs 1% [one of 122] of patients; P < .001), and SPSS (27% [30 of 111] vs 1% [one of 122] of patients; P < .001) were higher in the T-DM1 group than in the control group. Conclusion Trastuzumab emtansine therapy was associated with noncirrhotic portal hypertension at CT, with higher incidences of splenomegaly, gastroesophageal varix, and spontaneous portosystemic shunt than those with lapatinib and capecitabine therapy. © RSNA, 2022 Online supplemental material is available for this article.

Diagnostic performance of liver fibrosis assessment by quantification of liver surface nodularity on computed tomography and magnetic resonance imaging: systematic review and meta-analysis.

OBJECTIVES: To determine the diagnostic performance of the liver surface nodularity (LSN) score for assessment of hepatic fibrosis. METHODS: Major databases were searched to identify studies reporting the diagnostic performance of the LSN score published from January 2011 to April 2021. The pooled sensitivity and specificity of the LSN score in the diagnosis of significant fibrosis (F2-4), advanced fibrosis (F3-4), and liver cirrhosis (F4) were calculated using a bivariate random-effects model, and the summary areas under the hierarchical summary receiver operating characteristics curve (AUC) for each were calculated. Subgroup analysis was performed to explore the causes of study heterogeneity. RESULTS: Of 168 screened studies, six were included in the analysis. The pooled sensitivity, specificity, and AUC of the LSN score were 68% (95% confidence interval [CI], 45-84%), 89% (95% CI, 83-93%), and 0.90 (95% CI, 0.87-0.92), respectively, for the diagnosis of significant fibrosis; 88% (95% CI, 60-97%), 78% (95% CI, 57-90%), and 0.89 (95% CI, 0.86-0.91), respectively, for the diagnosis of advanced fibrosis; and 83% (95% CI, 71-91%), 80% (95% CI, 72-85%), and 0.87 (95% CI, 0.83-0.89), respectively, for the diagnosis of liver cirrhosis. Cutoff values of the LSN score affected study heterogeneity in the diagnosis of advanced fibrosis (p = 0.03) and liver cirrhosis (p = 0.01). Imaging modality (p = 0.01) and reference standard (p = 0.01) affected study heterogeneity in the diagnosis of liver cirrhosis. CONCLUSIONS: The LSN score showed good diagnostic performance in assessing the hepatic fibrosis stage. Additional investigations are needed to improve and standardize the LSN score. Key Points • The liver surface nodularity (LSN) score showed overall good diagnostic performance in assessing hepatic fibrosis. • The pooled sensitivity of the LSN score was highest in the diagnosis of advanced fibrosis (88%; 95% confidence interval [CI], 60-97%), and the pooled specificity was highest in the diagnosis of significant fibrosis (89%; 95% CI, 83-93%). • The diagnostic performance of the LSN score differed according to the cutoff value, imaging modality, and reference standard.

Diagnostic performance of ultrasound attenuation imaging for assessing low-grade hepatic steatosis.

OBJECTIVES: To investigate the diagnostic performance of attenuation imaging (ATI) for the assessment of low-grade hepatic steatosis using liver biopsy as the reference standard. METHODS: The study included 57 potential donor candidates for living liver transplantation who underwent ATI, transient elastography (TE), and liver biopsy for evaluation of hepatic steatosis between February 2020 and April 2020. The attenuation coefficient (AC) from ATI and the controlled attenuation parameter (CAP) from TE were measured for each participant in a random and blind manner. The histologic hepatic fat fraction (HFF) was graded (S0, < 5%; S1, 5-33%; S2, 33-66%; S3, > 66%). The accuracy of ATI for diagnosing hepatic steatosis was compared with that of CAP using ROC analysis. Correlations between AC and HFF were evaluated, and factors affecting AC were determined by linear regression analysis. RESULTS: The median HFF was 3% (range: 0-35%), with 31 (54.4%), 24 (42.0%), and 2 (3.5%) participants being graded as S0, S1, and S2, respectively. The AUCs for the ROCs of AC and CAP for the detection of hepatic steatosis were 0.808 (95% CI: 0.682-0.900) and 0.829 (95% CI: 0.706-0.916), respectively, with the difference not being statistically significant (p = 0.762). AC showed 61.5% of sensitivity and 90.3% of specificity. AC was positively correlated with HFF (p < 0.001). HFF was the only factor significantly affecting AC. CONCLUSIONS: ATI showed moderate sensitivity and high specificity in the diagnosis and quantification of hepatic steatosis in low-grade steatosis without fibrosis. Only HFF significantly affected AC. KEY POINTS: • Attenuation imaging showed moderate sensitivity and high specificity performance in the diagnosis and quantification of hepatic steatosis in low-grade steatosis without fibrosis. • The diagnostic performance of the attenuation coefficient by attenuation imaging did not significantly differ from that of the controlled attenuation parameter by transient elastography in quantifying low-grade steatosis. • The histopathologically determined hepatic fat fraction was the only factor significantly affecting the attenuation coefficient.

Diagnostic value of [68 Ga]Ga-DOTA-labeled-somatostatin analogue PET/MRI for detecting liver metastasis in patients with neuroendocrine tumors: a systematic review and meta-analysis.

OBJECTIVES: To determine the diagnostic value of [68 Ga]Ga-DOTA-labeled-somatostatin analogue ([68 Ga]Ga-DOTA-SSA) PET/MRI for detecting liver metastasis in patients with neuroendocrine tumor (NET) and to compare it with [68 Ga]Ga-DOTA-SSA PET/CT. METHODS: A search of MEDLINE, EMBASE, and Cochrane was performed to identify original articles reporting the detection rate of [68 Ga]Ga-DOTA-SSA PET/MRI for liver metastasis in comparison with PET/CT. The pooled detection rates for liver metastasis on PET/MRI and PET/CT were calculated and compared using a restricted maximum likelihood estimation of random-effects model. The pooled added value of PET/MRI in comparison with PET/CT was calculated. Sensitivity analysis and subgroup analysis were performed to explore causes of study heterogeneity. RESULTS: In the six included studies (638 liver metastases), the pooled detection rates for liver metastasis on [68 Ga]Ga-DOTA-SSA PET/MRI and PET/CT were 93.5% (95% confidence interval [CI], 85.1-97.3%; I2 = 84.8%) and 76.8% (95% CI, 64.8-85.6%; I2 = 87.8%), respectively. PET/MRI had a significantly higher detection rate than PET/CT (p = 0.02), with 15.3% (95% CI, 8.0-27.4%) added value over PET/CT. After sensitivity analysis, the recalculated detection rates for liver metastasis were 94.8% (95% CI, 90.8-97.2%; I2 = 42.1%) for PET/MRI and 80.0% (95% CI, 65.3-89.5%; I2 = 90.0%) for PET/CT. The study location and the use of predefined imaging criteria for liver metastasis were associated with PET/MRI study heterogeneity. CONCLUSION: [68 Ga]Ga-DOTA-SSA PET/MRI had good overall performance for detecting liver metastasis in patients with NET. Because of the small number of eligible studies, further studies are needed to validate the clinical usefulness of [68 Ga]Ga-DOTA-SSA PET/MRI. KEY POINTS: • [68 Ga]Ga-DOTA-SSA PET/MRI had a higher pooled detection rate for liver metastasis than PET/CT (93.5% vs. 76.8%). • The added value of [68 Ga]Ga-DOTA-SSA PET/MRI for detecting liver metastasis in comparison with PET/CT was 15.3%. •Study location and the predefined imaging criteria for liver metastasis were significant factors causing PET/MRI study heterogeneity.

CT in the prediction of margin-negative resection in pancreatic cancer following neoadjuvant treatment: a systematic review and meta-analysis.

OBJECTIVES: We aimed to systematically evaluate the diagnostic accuracy of CT-determined resectability following neoadjuvant treatment for predicting margin-negative resection (R0 resection) in patients with pancreatic ductal adenocarcinoma (PDAC). METHODS: Original studies with sufficient details to obtain the sensitivity and specificity of CT-determined resectability following neoadjuvant treatment, with a reference on the pathological margin status, were identified in PubMed, EMBASE, and Cochrane databases until February 24, 2020. The identified studies were divided into two groups based on the criteria of R0 resectable tumor (ordinary criterion: resectable PDAC alone; extended criterion: resectable and borderline resectable PDAC). The meta-analytic summary of the sensitivity and specificity for each criterion was estimated separately using a bivariate random-effect model. Summary results of the two criteria were compared using a joint-model bivariate meta-regression. RESULTS: Of 739 studies initially searched, 6 studies (6 with ordinary criterion and 5 with extended criterion) were included for analysis. The meta-analytic summary of sensitivity and specificity was 45% (95% confidence interval [CI], 19-73%; I2 = 88.3%) and 85% (95% CI, 65-94%; I2 = 60.5%) for the ordinary criterion, and 81% (95% CI, 71-87%; I2 = 0.0%) and 42% (95% CI, 28-57%; I2 = 6.2%) for the extended criterion, respectively. The diagnostic accuracy significantly differed between the two criteria (p = 0.02). CONCLUSIONS: For determining resectability on CT, the ordinary criterion might be highly specific but insensitive for predicting R0 resection, whereas the extended criterion increased sensitivity but would decrease specificity. Further investigations using quantitative parameters may improve the identification of R0 resection. KEY POINTS: • CT-determined resectability of PDAC after neoadjuvant treatment using the ordinary criterion shows low sensitivity and high specificity in predicting R0 resection. • With the extended criterion, CT-determined resectability shows higher sensitivity but lower specificity than with the ordinary criterion. • CT-determined resectability with both criteria achieved suboptimal diagnostic performances, suggesting that care should be taken while selecting surgical candidates and when determining the surgical extent after neoadjuvant treatment in patients with PDAC.

CT-determined resectability of borderline resectable and unresectable pancreatic adenocarcinoma following FOLFIRINOX therapy.

OBJECTIVES: We aimed to assess the ability of CT-determined resectability, as defined by a recent version of NCCN criteria, and associated CT findings to predict margin-negative (R0) resection in patients with PDAC after neoadjuvant FOLFIRINOX chemotherapy. METHODS: Sixty-four patients (36 men and 28 women; mean age, 58.8 years) with borderline resectable or unresectable PDAC who received neoadjuvant FOLFIRINOX were evaluated retrospectively. CT findings were independently assessed by two abdominal radiologists according to NCCN criteria (version 3. 2019). Tumor resectability was classified as resectable, borderline resectable, or unresectable, and change in resectability was classified as regression, stability, or progression. The associations of R0 resection rate with CT-determined resectability and change in resectability categories were evaluated, as were the sensitivity and specificity of NCCN criteria for R0 resection. Factors associated with R0 resection were identified by logistic regression analysis. RESULTS: R0 resection rate did not differ significantly among the resectable, borderline resectable, or unresectable PDAC (67-73%, p = 0.95) or among PDAC with regression, stability, or progression (56-77%, p = 0.39). The sensitivity and specificity for R0 resection were 67% and 37%, respectively, for resectability (resectable/borderline vs. unresectable) and 80% and 21%, respectively, for changes in resectability (regression/stable vs. progression). Low-contrast enhancement of soft tissue contacting artery (≤ 46.4 HU) was independently associated with R0 resection (p = 0.01). CONCLUSION: CT-determined resectability after neoadjuvant FOLFIRINOX chemotherapy was relatively insensitive and non-specific for predicting R0 resection. Low-contrast enhancement of soft tissue contacting artery may increase the ability of CT to predict R0 resection. KEY POINTS: • Margin-negative resection rate of pancreatic cancer following FOLFIRINOX therapy did not differ among each resectability (67-73%, p = 0.95) based on NCCN criteria or changes in resectability categories (56-77%, p = 0.39). • The sensitivity and specificity for margin-negative resection were 67% and 37% for resectability (resectable/borderline vs. unresectable) and 80% and 21% for changes in resectability (regression/stable vs. progression). • Low-contrast enhancement of soft tissue contacting artery (≤ 46.4 HU) was independently associated with margin-negative resection (p = 0.01).

Hepatocyte-Specific Magnetic Resonance Imaging-Based Assessment of Indeterminate Hepatic Nodules in the Liver Transplant Evaluation of Patients With Cirrhosis.

We aimed to determine the identities in explants of indeterminate hepatic nodules (IDNs) that had been scanned by dynamic magnetic resonance imaging (MRI) to establish clinicoradiological parameters predicting which IDNs were hepatocellular carcinomas (HCCs). This study included 88 patients with cirrhosis who underwent gadoxetic acid-enhanced MRI in pre-liver transplantation (LT) workup followed within 90 days by primary LT. The MRI detected 168 hepatic nodules that were classified into 6 benign tumors, 49 HCCs, and 113 IDNs, in 5, 34, and 72 patients, respectively. We compared these pre-LT radiologic diagnoses and stagings with explant pathology on a per-lesion basis to enable us to identify features of IDNs related to malignancy. Of the 168 nodules seen on MRI, 119 that were classified radiologically as consisting of 1 benign nodule (33.3%), 46 HCCs (93.9%), and 72 IDNs (63.7%) all turned out to be pathological HCCs. Of 32 patients inside Milan and 54 without HCC staged by MRI, 11 progressed beyond the criteria after LT. High serum alpha-fetoprotein level (≥20 ng/mL) was the only per-patient factor significantly associated with malignant IDNs. Per-tumor analysis of the MRI signals revealed that arterial hyperintensity, hepatobiliary hypointensity, T2 -weighted mild-to-moderate intensity, and restricted diffusion-weighted images were significantly correlated with malignant IDN. A model combining these 4 MRI factors with alpha-fetoprotein level had the best performance in predicting the identification of IDNs as HCCs in explanted livers. Over 60% of the IDNs seen on dynamic images of cirrhotic livers proved to be HCCs when explanted livers were examined. It may therefore be possible to identify HCCs with reasonable accuracy by means of their hepatocyte-specific MRI features when patients are being assessed for LT.

MR tumor regression grade for pathological complete response in rectal cancer post neoadjuvant chemoradiotherapy: a systematic review and meta-analysis for accuracy.

OBJECTIVES: To determine the diagnostic accuracy of magnetic resonance tumor regression grade (mrTRG) for pathological complete response (pCR) and its correlation with pathological findings. METHODS: Original studies that investigated the correlation of mrTRG with pathological tumor regression grade and pathological T stage were identified in MEDLINE and EMBASE up until August 31, 2018, according to PRISMA guidelines. The search terms included colorectal cancer, chemoradiation therapy, magnetic resonance imaging, and response or regression. Meta-analytic summary sensitivity and specificity for pathologic complete response (pCR) and pathologic T1 or lower than T1 stage (≤ypT1) were calculated using a bivariate random-effects model. The sensitivity and specificity were calculated in both mrTRG 1 and mrTRG 1 or 2, respectively. RESULTS: Six studies with 916 patients were included. The meta-analytic summary sensitivity and specificity of mrTRG 1 for pCR were 32.3% (95% CI, 18.2-50.6%) and 93.5% (95% CI, 91.5-95.1%), while for ≤ypT1 they were 31.8% (95% CI, 16.2-53.0%) and 94.7% (95% CI, 91.9-96.5%). On the contrary, sensitivity and specificity of mrTRG 1 or 2 for pCR were 69.9% (95% CI, 60.2-78.1%) and 62.2% (95% CI, 56.2-67.8%), while those for ≤ypT1 were 71.4% (95% CI, 61.6-79.6%) and 67.7% (95% CI, 59.8-74.7%). CONCLUSIONS: mrTRG 1 showed high specificity for pCR and ≤ypT1, but suboptimal sensitivity. mrTRG 1 or 2 showed higher sensitivity for pCR and ≤ypT1, but lower specificity. Because of the suboptimal sensitivity of mrTRG 1, it might be limited as a criterion for less aggressive treatment after neoadjuvant chemoradiotherapy. KEY POINTS: • Magnetic resonance tumor regression grade 1 shows high specificity for pCR and ≤ypT1, but suboptimal sensitivity. • Magnetic resonance tumor regression grade 1 or 2 shows higher sensitivity for pCR and ≤ypT1, but lower specificity than magnetic resonance tumor regression grade 1 alone.

A Review of the Spectrum of Imaging Manifestations of Epithelioid Hemangioendothelioma.

OBJECTIVE. The purpose of this article is to review the spectrum of imaging manifestations of epithelioid hemangioendothelioma across different organ systems and briefly describe its current treatment strategies. CONCLUSION. Epithelioid hemangioendothelioma is a rare, locally invasive neoplasm with metastatic potential. Although most commonly occurring in liver, lungs, and bones, it can also present at multiple other sites. Because of its nonspecific clinical and imaging manifestations, it is often misdiagnosed. The possibility of epithelioid hemangioendothelioma must be considered in the presence of a slowly growing mass that invades adjacent structures. Imaging can help plan percutaneous biopsy, detect sites of disease, and identify poor prognostic factors.

CT of acute rejection after liver transplantation: a matched case-control study.

PURPOSE: This study was conducted in order to investigate computed tomography (CT) findings associated with acute cellular rejection (ACR) following liver transplantation (LT) and their relevance to clinical outcomes. MATERIALS AND METHODS: We analyzed 120 patients with newly diagnosed ACR following LT for various liver diseases and 119 controls matched for age, sex, type of liver graft, and date of CT exam following LT. Two radiologists analyzed the images for morphological characteristics of the graft, morphological change in the major draining vein, graft enhancement in the portal venous phase, graft attenuation on noncontrast CT, and periportal halo. Univariate analysis was used to determine the association between radiological findings and ACR. Clinical outcomes, including treatment response and graft survival, were compared between patients with and without associated radiological findings. RESULTS: Morphological characteristics of the graft (i.e., globular swelling), morphological change in the major draining vein (i.e., nonanastomotic luminal narrowing), and heterogeneous enhancement were significantly associated with ACR (all p < 0.001). On univariate analysis, the severity of morphological characteristics of the grafts (mild/severe: odds ratio [OR], 19.98/32.24) and morphological change in the major draining vein (without/with prestenotic dilatation: OR, 4.17/22.5) were significantly associated with the increased possibility of an ACR diagnosis. Clinical outcomes for treatment response and graft survival were not significantly different between patients with and without associated radiological findings. CONCLUSIONS: Globular swelling, nonanastomotic stenosis with or without prestenotic dilatation of the major draining vein, and heterogeneous enhancement of the graft on portal venous-phase CT were significantly associated with ACR. KEY POINTS: • Globular swelling of the graft, nonanastomotic narrowing in the major vein, and heterogeneous graft enhancement on CT were significantly associated with acute cellular rejection (ACR). • Associated CT findings were highly specific but not sensitive for differentiating ACRs from matched controls.

Development and Validation of a Deep Learning System for Staging Liver Fibrosis by Using Contrast Agent-enhanced CT Images in the Liver.

Purpose To develop and validate a deep learning system (DLS) for staging liver fibrosis by using CT images in the liver. Materials and Methods DLS for CT-based staging of liver fibrosis was created by using a development data set that included portal venous phase CT images in 7461 patients with pathologically confirmed liver fibrosis. The diagnostic performance of the DLS was evaluated in separate test data sets for 891 patients. The influence of patient characteristics and CT techniques on the staging accuracy of the DLS was evaluated by logistic regression analysis. In a subset of 421 patients, the diagnostic performance of the DLS was compared with that of the radiologist's assessment, aminotransferase-to-platelet ratio index (APRI), and fibrosis-4 index by using the area under the receiver operating characteristic curve (AUROC) and Obuchowski index. Results In the test data sets, the DLS had a staging accuracy of 79.4% (707 of 891) and an AUROC of 0.96, 0.97, and 0.95 for diagnosing significant fibrosis (F2-4), advanced fibrosis (F3-4), and cirrhosis (F4), respectively. At multivariable analysis, only pathologic fibrosis stage significantly affected the staging accuracy of the DLS (P = .016 and .013 for F1 and F2, respectively, compared with F4), whereas etiology of liver disease and CT technique did not. The DLS (Obuchowski index, 0.94) outperformed the radiologist's interpretation, APRI, and fibrosis-4 index (Obuchowski index range, 0.71-0.81; P ˂ .001) for staging liver fibrosis. Conclusion The deep learning system allows for accurate staging of liver fibrosis by using CT images. © RSNA, 2018 Online supplemental material is available for this article.

MRI in donor candidates for living donor liver transplant: Technical and practical considerations.

In living donor liver transplantation (LDLT), a thorough preoperative evaluation of the donor is imperative to minimize the risk of the donors and improve the outcome of the recipients. In order to select the best candidate, knowledge of the liver volume, degree of steatosis, and anatomic variations in the vascular and biliary system in potential donors is crucial. With recent technical advances, magnetic resonance imaging (MRI) is increasingly replacing the need for computed tomography (CT) examination in essential steps of donor evaluation. Along with the introduction of higher gradient strength, novel pulse sequences, and innovative contrast media, MRI has a potential to serve as an "all-in-one" imaging package. In this review, we provide an overview of clinical and radiologic considerations related to LDLT and highlight the basics and up-to-date knowledge of MRI techniques for a comprehensive donor evaluation. Level of Evidence: 5 Technical Efficacy: Stage 5 J. Magn. Reson. Imaging 2018;48:1453-1467.

Interpretation of Complete Tumor Response on MRI Following Chemoradiotherapy of Rectal Cancer: Inter-Reader Agreement and Associated Factors in Multi-Center Clinical Practice.

OBJECTIVE: To measure inter-reader agreement and identify associated factors in interpreting complete response (CR) on magnetic resonance imaging (MRI) following chemoradiotherapy (CRT) for rectal cancer. MATERIALS AND METHODS: This retrospective study involved 10 readers from seven hospitals with experience of 80-10210 cases, and 149 patients who underwent surgery after CRT for rectal cancer. Using MRI-based tumor regression grading (mrTRG) and methods employed in daily practice, the readers independently assessed mrTRG, CR on T2-weighted images (T2WI) denoted as mrCRT2W, and CR on all images including diffusion-weighted images (DWI) denoted as mrCRoverall. The readers described their interpretation patterns and how they utilized DWI. Inter-reader agreement was measured using multi-rater kappa, and associated factors were analyzed using multivariable regression. Correlation between sensitivity and specificity of each reader was analyzed using Spearman coefficient. RESULTS: The mrCRT2W and mrCRoverall rates varied widely among the readers, ranging 18.8%-40.3% and 18.1%-34.9%, respectively. Nine readers used DWI as a supplement sequence, which modified interpretations on T2WI in 2.7% of cases (36/1341 [149 patients × 9 readers]) and mostly (33/36) changed mrCRT2W to non-mrCRoverall. The kappa values for mrTRG, mrCRT2W, and mrCRoverall were 0.56 (95% confidence interval: 0.49, 0.62), 0.55 (0.52, 0.57), and 0.54 (0.51, 0.57), respectively. No use of rectal gel, larger initial tumor size, and higher initial cT stage exhibited significant association with a higher inter-reader agreement for assessing mrCRoverall (P ≤ 0.042). Strong negative correlations were observed between the sensitivity and specificity of individual readers (coefficient, -0.718 to -0.963; P ≤ 0.019). CONCLUSION: Inter-reader agreement was moderate for assessing CR on post-CRT MRI. Readers' varying standards on MRI interpretation (i.e., threshold effect), along with the use of rectal gel, initial tumor size, and initial cT stage, were significant factors associated with inter-reader agreement.

Comparison of the different versions of NCCN guidelines for predicting margin-negative resection of pancreatic cancer in patients undergoing upfront surgery.

OBJECTIVES: The purpose of this study was to compare the different versions of the National Comprehensive Cancer Network (NCCN) guidelines for defining resectability of pancreatic ductal adenocarcinoma (PDAC) in predicting margin-negative (R0) resection, and to assess inter-reader agreement. METHODS: This retrospective study included 283 patients (mean age, 65.1 years ± 9.4 [SD]; 155 men) who underwent upfront pancreatectomy for PDAC between 2017 and 2019. Two radiologists independently determined the resectability on preoperative CT according to the 2017, 2019, and 2020 NCCN guidelines. The sensitivity and specificity for R0 resection were analyzed using a multivariable logistic regression analysis with generalized estimating equations. Inter-reader agreement was assessed using kappa statistics. RESULTS: R0 resection was accomplished in 239 patients (84.5%). The sensitivity and specificity averaged across two readers were, respectively, 76.6% and 29.5% for the 2020 guidelines, 74.1% and 32.9% for the 2019 guidelines, and 72.6% and 34.1% for the 2017 guidelines. Compared with the 2020 guidelines, both 2019 and 2017 guidelines showed significantly lower sensitivity for R0 resection (p ≤ .009). Specificity was significantly higher with the 2017 guidelines (p = .043) than with the 2020 guidelines. Inter-reader agreements for determining the resectability of PDCA were strong (k ≥ 0.83) with all guidelines, being highest with the 2020 guidelines (k = 0.91). CONCLUSION: The 2020 NCCN guidelines showed significantly higher sensitivity for prediction of R0 resection than the 2017 and 2019 guidelines.

Deep learning-based imaging reconstruction for MRI after neoadjuvant chemoradiotherapy for rectal cancer: effects on image quality and assessment of treatment response.

PURPOSE: To investigate the effects of deep learning-based imaging reconstruction (DLR) on the image quality of MRI of rectal cancer after chemoradiotherapy (CRT), and its accuracy in diagnosing pathological complete responses (pCR). METHODS: We included 39 patients (men: women, 21:18; mean age ± standard deviation, 59.1 ± 9.7 years) with mid-to-lower rectal cancer who underwent a long-course of CRT and high-resolution rectal MRIs between January 2020 and April 2021. Axial T2WI was reconstructed using the conventional method (MRIconv) and DLR with two different noise reduction factors (MRIDLR30 and MRIDLR50). The signal-to-noise ratio (SNR) of the tumor was measured. Two experienced radiologists independently made a blind assessment of the complete response on MRI. The sensitivity and specificity for pCR were analyzed using a multivariable logistic regression analysis with generalized estimating equations. RESULTS: Thirty-four patients did not have a pCR whereas five (12.8%) had pCR. Compared with the SNR of MRIconv (mean ± SD, 7.94 ± 1.92), MRIDLR30 and MRIDLR50 showed higher SNR (9.44 ± 2.31 and 11.83 ± 3.07, respectively) (p < 0.001). Compared to MRIconv, MRIDLR30 and MRIDLR50 showed significantly higher specificity values (p < 0.036) while the sensitivity values were not significantly different (p > 0.301). The sensitivity and specificity for pCR were 48.9% and 80.8% for MRIconv; 48.9% and 88.2% for MRIDLR30; and 38.8% and 86.7% for MRIDLR50, respectively. CONCLUSION: DLR produced MR images with higher resolution and SNR. The specificity of MRI for identification of pCR was significantly higher with DLR than with conventional MRI.

Transient elastography with controlled attenuation parameter versus two-dimensional shear wave elastography with attenuation imaging for the evaluation of hepatic steatosis and fibrosis in NAFLD.

PURPOSE: This study compared the controlled attenuation parameter (CAP) to attenuation imaging (ATI) in the diagnosis of steatosis and transient elastography (TE) to two-dimensional shear wave elastography (2D-SWE) for the diagnosis of fibrosis in a prospectively constructed nonalcoholic fatty liver disease (NAFLD) patient cohort. METHODS: Participants who underwent TE with CAP were included from a previously constructed NAFLD cohort with multiparametric ultrasound data. The degree of hepatic steatosis and stage of liver fibrosis were assessed. Diagnostic performance was evaluated using the area under the receiver operating characteristic curve (AUROC) for the grades of steatosis (S1-3) and fibrosis (F0-F4). RESULTS: There were 105 participants. The distribution of hepatic steatosis grades (S0-S3) and liver fibrosis stages (F0-F4) was as follows: S0, n=34; S1, n=41; S2, n=22; S3, n=8; F0, n=63; F1, n=25; F2, n=5; F3, n=7; and F4, n=5. No significant difference was found between CAP and ATI in detecting ≥S1 (AUROC: 0.93 vs. 0.93, P=0.956) or ≥S2 (0.94 vs. 0.94, P=0.769). However, the AUROC of ATI in detecting ≥S3 was significantly higher than that of CAP (0.94 vs. 0.87, P=0.047). Regarding the detection of liver fibrosis, no significant difference was found between TE and 2D-SWE. The AUROCs of TE and 2D-SWE were as follows: ≥F1, 0.94 vs. 0.89 (P=0.107); ≥F2, 0.89 vs. 0.90 (P=0.644); ≥F3, 0.91 vs. 0.90 (P=0.703); and ≥F4, 0.88 vs. 0.92 (P=0.209). CONCLUSION: 2D-SWE and TE showed comparable diagnostic performance in assessing liver fibrosis, and ATI provided significantly better performance in detecting ≥S3 steatosis than CAP.

Value of Doppler ultrasonography in predicting clinical outcomes for patients with acute cellular rejection after liver transplantation.

PURPOSE: This study investigated the value of Doppler ultrasonography in predicting clinical outcomes after antirejection treatment for patients with acute cellular rejection (ACR) following liver transplantation (LT). METHODS: This retrospective study included 84 patients who were pathologically diagnosed with ACR and received antirejection treatment within 90 days following LT. Two radiologists searched for abnormal Doppler parameters at ACR diagnosis and within 7 days after antirejection treatment initiation, including portal blood velocity (PBV) <20 cm/s, hepatic artery resistive index <0.5, and a monophasic hepatic vein flow pattern. Interval PBV changes were also evaluated. The frequencies of abnormal Doppler parameters and PBV changes were compared by treatment outcome. RESULTS: The frequency of abnormal PBV in the early post-treatment phase (PBVearly post-treatment) was significantly higher among poor responders (50.0% [10/20]) than among good responders (7.8% [5/64]) (P<0.001). The sensitivity, specificity, and accuracy of abnormal PBVearly post-treatment as a predictor of poor response to antirejection treatment were 50.0% (10/20), 92.2% (59/64), and 82.1% (69/84), respectively. A decrease (>10%) from the PBV at event (PBVevent) to PBVearly post-treatment was significantly more common among poor responders (50.0% [10/20]) than among good responders (20.3% [13/64]) (P=0.019). The sensitivity, specificity, and accuracy of this PBV decrease in predicting poor treatment response were 50.0% (10/20), 79.7% (51/64), and 72.6% (61/84), respectively. CONCLUSION: Abnormal PBVearly post-treatment and a decrease between PBVevent and PBVearly post-treatment were significantly associated with poor treatment response in patients with ACR after LT. Consequently, Doppler ultrasonography may be useful for predicting clinical outcomes in these patients.

Pathologic Implications of Magnetic Resonance Imaging-detected Extramural Venous Invasion of Rectal Cancer.

BACKGROUND: Extramural venous invasion (EMVI) is a poor prognostic factor in rectal cancer. Recent advances in magnetic resonance imaging (MRI) allow for the detection of EMVI before surgery. This study aimed to analyze the correlations between MRI-detected EMVI (MR-EMVI) and pathologic parameters in patients with rectal cancer. MATERIALS AND METHODS: This study retrospectively analyzed 721 patients who underwent radical resection for locally advanced rectal cancer between 2018 and 2019 at the Asan Medical center. All patients underwent an MRI before surgery. The lesions of patients who received neoadjuvant chemoradiation therapy (CRT) were evaluated by MRI before and after the neoadjuvant CRT. RESULTS: Of the 721 patients, 118 (16.4%) showed a positive MR-EMVI, which significantly correlated with advanced pathologic T-category and N-category, extranodal extension, poor differentiation, lymphatic invasion, venous invasion, and perineural invasion. In addition, MR-EMVI was an independent factor for predicting the pathologic nodal status (OR 3.476, 95% CI, 2.186-5.527, P < .001). Patients with a positive MR-EMVI had a sensitivity of 28.0% and specificity of 91.9% for predicting regional lymph node metastasis, whereas the MR-N category had a sensitivity of 88.7% and specificity of 30.6%. Patients whose MR-EMVI changed from positive to negative after neoadjuvant CRT had no significant differences in pathologic parameters except for lymphatic invasion with patients who were negative before and after neoadjuvant CRT. CONCLUSION: MR-EMVI correlated with aggressive pathologic features, which indicated a poor prognosis. MR-EMVI may be a complementary imaging biomarker for predicting nodal status and evaluating tumor response to neoadjuvant CRT.