Correlation Between Computed Tomography Findings and the Laboratory Test-Derived Severity Score in Patients With Severe Acute Alcoholic Hepatitis.

OBJECTIVE: This study aimed to compare computed tomography (CT) findings between patients with severe and nonsevere acute alcoholic hepatitis (AAH). METHODS: We included 96 patients diagnosed with AAH between January 2011 and October 2021 who underwent 4-phase liver CT and laboratory blood tests. Two radiologists reviewed the initial CT images with respect to distribution and grade of hepatic steatosis; transient parenchymal arterial enhancement (TPAE); and presence of cirrhosis, ascites, and hepatosplenomegaly. A Maddrey discriminant function score (4.6 × [patient's prothrombin time - control] + total bilirubin [mg/mL]) was used as cutoff indicator for severity, with a score of 32 or higher indicating severe disease. The image findings were compared between the severe (n = 24) and nonsevere (n = 72) groups using the χ 2 test or Fisher exact test. After univariate analysis, the most significant factor was identified using a logistic regression analysis. RESULTS: In the univariate analysis, there were significant between-group differences in the TPAE, liver cirrhosis, splenomegaly, and ascites ( P < 0.0001, P < 0.0001, P = 0.0002, and P = 0.0163, respectively). Among them, TPAE was the only significant factor for severe AAH ( P < 0.0001; odds ratio, 48.1; 95% confidence interval, 8.3-280.6). Using this single indicator, the estimated accuracy, positive predictive, and negative predictive values were 86%, 67%, and 97%, respectively. CONCLUSIONS: Transient parenchymal arterial enhancement was the only significant CT finding in severe AAH.

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).

Assessment of liver fibrosis severity using computed tomography-based liver and spleen volumetric indices in patients with chronic liver disease.

OBJECTIVES: To evaluate whether the liver and spleen volumetric indices, measured on portal venous phase CT images, could be used to assess liver fibrosis severity in chronic liver disease. METHODS: From 2007 to 2017, 558 patients (mean age 48.7 ± 13.1 years; 284 men and 274 women) with chronic liver disease (n = 513) or healthy liver (n = 45) were retrospectively enrolled. The liver volume (sVolL) and spleen volume (sVolS), normalized to body surface area and liver-to-spleen volume ratio (VolL/VolS), were measured on CT images using a deep learning algorithm. The correlation between the volumetric indices and the pathologic liver fibrosis stages combined with the presence of decompensation (F0, F1, F2, F3, F4C [compensated cirrhosis], and F4D [decompensated cirrhosis]) were assessed using Spearman's correlation coefficient. The performance of the volumetric indices in the diagnosis of advanced fibrosis, cirrhosis, and decompensated cirrhosis were evaluated using the area under the receiver operating characteristic curve (AUC). RESULTS: The sVolS (ρ = 0.47-0.73; p < .001) and VolL/VolS (ρ = -0.77-- 0.48; p < .001) showed significant correlation with liver fibrosis stage in all etiological subgroups (i.e., viral hepatitis, alcoholic and non-alcoholic fatty liver, and autoimmune diseases), while the significant correlation of sVolL was noted only in the viral hepatitis subgroup (ρ = - 0.55; p < .001). To diagnose advanced fibrosis, cirrhosis, and decompensated cirrhosis, the VolL/VolS (AUC 0.82-0.88) and sVolS (AUC 0.82-0.87) significantly outperformed the sVolL (AUC 0.63-0.72; p < .001). CONCLUSION: The VolL/VolS and sVolS may be used for assessing liver fibrosis severity in chronic liver disease. KEY POINTS: • Volumetric indices of liver and spleen measured on computed tomography images may allow liver fibrosis severity to be assessed in patients with chronic liver disease.

Relationship between Lower Dose and Injection Speed of Iodinated Contrast Material for CT and Acute Hypersensitivity Reactions: An Observational Study.

BackgroundThere are few data on the relationship between acute hypersensitivity reactions and the dose and injection rate of iodinated contrast material for CT.PurposeTo determine the relationship between lower dose and injection speed of iodinated contrast material for CT and the rate of acute hypersensitivity reactions.Materials and MethodsThis retrospective study included adults (age ≥18 years) undergoing nonionic iodinated contrast material-enhanced abdominal CT between August 2016 and January 2017 (control period) and between August 2017 and January 2018 (intervention period); all examinations were conducted in an outpatient setting. Compared with CT during the control period, CT during the intervention period involved a reduced dose of contrast material achieved by lowering the CT tube voltage. CT examinations in the control period were performed with 120 kVp, a contrast material dose of 2 mL/kg (maximum, 150 mL), and an injection speed of 3 or 4 mL/sec. CT examinations in the intervention period were performed with 100 kVp, a contrast material dose of 1.5 mL/kg (maximum, 130 mL), and an injection speed of 2.5 or 3 mL/sec. Per-examination rates of acute hypersensitivity reactions to iodinated contrast material were compared between the control and intervention periods with use of a multivariable Poisson regression model, the parameters of which were estimated by using generalized estimating equations with an independence correlation structure.ResultsA total of 21947 adults (mean age ± standard deviation, 59 years ± 12; 8797 women [40%]) underwent 25119 CT examinations during the control period; 23019 adults (mean age, 59 years ± 12; 9538 women [41%]) underwent 26491 CT examinations during the intervention period. The rate of acute hypersensitivity reactions was 1.42% (376 of 26491 examinations; 95% confidence interval [CI]: 1.28%, 1.57%) in the intervention period and 1.86% (468 of 25119 examinations; 95% CI: 1.70%, 2.04%) in the control period, with a multivariable-adjusted relative risk of 0.85 (95% CI: 0.74, 0.99; P = .03).ConclusionReduction in the dose and injection speed of iodinated contrast material for CT was associated with a lower rate of acute hypersensitivity reactions to iodinated contrast material.© RSNA, 2019Online supplemental material is available for this article.

Validation of US Liver Imaging Reporting and Data System Version 2017 in Patients at High Risk for Hepatocellular Carcinoma.

Background The 2017 version of the Liver Imaging Reporting and Data System (LI-RADS) recently included standardized interpretation, reporting, and management guidelines for US (US LI-RADS); however, this system has not yet been validated. Purpose To evaluate the diagnostic performance of US LI-RADS version 2017 for detecting hepatocellular carcinoma (HCC) in participants at high risk and to determine the clinical factors associated with a poor visualization score. Materials and Methods This study included 407 prospectively recruited participants (mean age, 56 years; age range, 28-76 years) with cirrhosis at high risk for HCC who underwent US surveillance from November 2011 to August 2012. Two radiologists retrospectively analyzed US images, assigning a LI-RADS category (US-1 = negative, US-2 = subthreshold, US-3 = positive) and a visualization score (A = no or minimal limitations, B = moderate limitations, C = severe limitations). The sensitivity and specificity for diagnosing HCC were calculated on a per-patient and per-lesion basis, using pathologic results and typical CT or MRI as reference standards. The risk factors for a poor visualization score were determined by using univariable and multivariable analyses. Results Of 429 lesions in 407 participants, there were 32 HCCs in 28 participants. In the per-lesion analysis, the specificity for US-3 was 366 of 397 (92%; 95% confidence interval [CI]: 89%, 95%) and the sensitivity was 11 of 32 (34%; 95% CI: 20%, 52%). In the per-patient analysis, the specificity for US-3 was 352 of 379 (93%; 95% CI: 90%, 95%) and the sensitivity was 11 of 28 (39%; 95% CI: 24%, 58%). Visualization score C (114 of 407 [28%] participants) had the highest false-negative rate (six of seven [86%] participants). High body weight (adjusted odds ratio [OR], 2.1 [95% CI: 1.2, 3.6]; P = .01), Child-Pugh class B disease (OR, 2.9 [95% CI: 1.7, 4.9]; P < .001), and moderate to severe fatty liver (OR, 1.7 [95% CI: 1.0, 2.8]; P = .047) were associated with a poor visualization score of C. Conclusion The US-3 category demonstrated high specificity but low sensitivity for diagnosing hepatocellular carcinoma. The visualization score C had a higher false-negative rate than scores A or B, and patients with high body weight, Child-Pugh class B disease, and moderate to severe fatty liver may present limitations for US surveillance. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Milot in this issue.

Comparison of Model-Based Iterative Reconstruction, Adaptive Statistical Iterative Reconstruction, and Filtered Back Projection for Detecting Hepatic Metastases on Submillisievert Low-Dose Computed Tomography.

OBJECTIVE: The aim of the study was to compare the diagnostic performance of model-based iterative reconstruction (MBIR), adaptive statistical iterative reconstruction (ASIR), and filtered back projection (FBP) on submillisievert low-dose computed tomography (LDCT) for detecting hepatic metastases. METHODS: Thirty-eight patients having hepatic metastases underwent abdomen CT. Computed tomography protocol consisted of routine standard-dose portal venous phase scan (120 kVp) and 90-second delayed low-dose scan (80 kVp). The LDCT images were reconstructed with FBP, ASIR, and MBIR, respectively. Two readers recorded the number of hepatic metastases on each image set. RESULTS: A total of 105 metastatic lesions were analyzed. For reader 1, sensitivity for detecting metastases was stationary between FBP (49%) and ASIR (52%, P = 0.0697); however, sensitivity increased in MBIR (66%, P = 0.0035). For reader 2, it was stationary for all the following sets: FBP (65%), ASIR (68%), and MBIR (67%, P > 0.05). CONCLUSIONS: The MBIR and ASIR showed a limited sensitivity for detecting hepatic metastases in submillisievert LDCT.

Low-dose CT for patients with clinically suspected acute appendicitis: optimal strength of sinogram affirmed iterative reconstruction for image quality and diagnostic performance.

BACKGROUND: As there is increased concern over the radiation exposure particularly in adolescents and young adults, computed tomography (CT) dose reduction is needed in the diagnosis of acute appendicitis. PURPOSE: To evaluate the optimal strength of sinogram affirmed iterative reconstruction (SAFIRE) to obtain the best image quality on a 30-mAs applied low-dose CT (LDCT 30mAs) and to compare the diagnostic performances of the LDCT 30mAs with different SAFIRE strengths with that of the 100-mAs applied LDCT (LDCT 100mAs) for the diagnosis of acute appendicitis. MATERIAL AND METHODS: A total of 102 consecutive patients (47 men, 55 women; mean age, 41.2 years; range, 15-82 years) with right lower quadrant pain underwent abdominal-pelvic CT, consisting of arterial phase LDCT 100mAs and portal venous phase LDCT30mAs under a fixed 120 kV. LDCT 30mAs images were reconstructed separately with five strength levels (S1-S5). Two blinded radiologists recorded scores for the subjective image quality of the LDCT 30mAs dataset (S0-S5) and confidence scores for the diagnosis of acute appendicitis on each dataset and LDCT 100mAs. CT image noise was measured for each set. RESULTS: The study population consisted of 58 patients with confirmed appendicitis and 44 without appendicitis. There was no significant difference in diagnostic performance between LDCT 100mAs and LDCT 30mAs with any strength for both readers (AUC for reader 1, LDCT 30mAs with S0-S5 = 0.97, LDCT 100mAs = 0.93, P = 0.0936; for reader 2, LDCT 30mAs with S0-S5 = 0.96, LDCT 100mAs = 0.97, P = 0.128). The measured noise decreased as the strength increased from S0 to S5 (mean, 20.8 > 17.7 > 15.6 > 13.5 > 11.5 > 9.5, P < 0.0001). However, overall subjective image quality on S3 was better than the other strengths for both readers (S0 < S1 < S2 < S3 > S4 > S5, P < 0.0001). CONCLUSION: Although measured noise declined as SAFIRE strength increased, S3 seems optimal for the best subjective image quality on LDCT 30mAs. The diagnostic performance of LDCT 30mAs with any strength is comparable to that of LDCT 100mAs for the diagnosis of acute appendicitis.

Impact of deep learning-based reconstruction and anti-peristaltic agent on the image quality and diagnostic performance of magnetic resonance enterography comparing single breath-hold single-shot fast spin echo with and without anti-peristaltic agent.

Background: While anti-peristaltic agents are beneficial for high quality magnetic resonance enterography (MRE), their use is constrained by potential side effects and increased examination complexity. We explored the potential of deep learning-based reconstruction (DLR) to compensate for the absence of anti-peristaltic agent, improve image quality and reduce artifact. This study aimed to evaluate the need for an anti-peristaltic agent in single breath-hold single-shot fast spin-echo (SSFSE) MRE and compare the image quality and artifacts between conventional reconstruction (CR) and DLR. Methods: We included 45 patients who underwent MRE for Crohn's disease between October 2021 and September 2022. Coronal SSFSE images without fat saturation were acquired before and after anti-peristaltic agent administration. Four sets of data were generated: SSFSE CR with and without an anti-peristaltic agent (CR-A and CR-NA, respectively) and SSFSE DLR with and without an anti-peristaltic agent (DLR-A and DLR-NA, respectively). Two radiologists independently reviewed the images for overall quality and artifacts, and compared the three images with DLR-A. The degree of distension and inflammatory parameters were scored on a 5-point scale in the jejunum and ileum, respectively. Signal-to-noise ratio (SNR) levels were calculated in superior mesenteric artery (SMA) and iliac bifurcation level. Results: In terms of overall quality, DLR-NA demonstrated no significant difference compared to DLR-A, whereas CR-NA and CR-A demonstrated significant differences (P<0.05, both readers). Regarding overall artifacts, reader 1 rated DLR-A slightly better than DLR-NA in four cases and rated them as identical in 41 cases (P=0.046), whereas reader 2 demonstrated no difference. Bowel distension was significantly different in the jejunum (Reader 1: P=0.046; Reader 2: P=0.008) but not in the ileum. Agreements between the images (Reader 1: ĸ=0.73-1.00; Reader 2: ĸ=1.00) and readers (ĸ=0.66 for all comparisons) on inflammation were considered good to excellent. The sensitivity, specificity, and accuracy in diagnosing inflammation in the terminal ileum were the same among DLR-NA, DLR-A, CR-NA and CR-A (94.42%, 81.83%, and 89.69 %; and 83.33%, 90.91%, and 86.21% for Readers 1 and 2, respectively). In both SMA and iliac bifurcation levels, SNR of DLR images exhibited no significant differences. CR images showed significantly lower SNR compared with DLR images (P<0.001). Conclusions: SSFSE without anti-peristaltic agents demonstrated nearly equivalent quality to that with anti-peristaltic agents. Omitting anti-peristaltic agents before SSFSE and adding DLR could improve the scanning outcomes and reduce time.

LAVA HyperSense and deep-learning reconstruction for near-isotropic (3D) enhanced magnetic resonance enterography in patients with Crohn's disease: utility in noise reduction and image quality improvement.

PURPOSE: This study aimed to compare near-isotropic contrast-enhanced T1-weighted (CE-T1W) magnetic resonance enterography (MRE) images reconstructed with vendor-supplied deep-learning reconstruction (DLR) with those reconstructed conventionally in terms of image quality. METHODS: A total of 35 patients who underwent MRE for Crohn's disease between August 2021 and February 2022 were included in this retrospective study. The enteric phase CE-T1W MRE images of each patient were reconstructed with conventional reconstruction and no image filter (original), with conventional reconstruction and image filter (filtered), and with a prototype version of AIRTM Recon DL 3D (DLR), which were then reformatted into the axial plane to generate six image sets per patient. Two radiologists independently assessed the images for overall image quality, contrast, sharpness, presence of motion artifacts, blurring, and synthetic appearance for qualitative analysis, and the signal-to-noise ratio (SNR) was measured for quantitative analysis. RESULTS: The mean scores of the DLR image set with respect to overall image quality, contrast, sharpness, motion artifacts, and blurring in the coronal and axial images were significantly superior to those of both the filtered and original images (P < 0.001). However, the DLR images showed a significantly more synthetic appearance than the other two images (P < 0.05). There was no statistically significant difference in all scores between the original and filtered images (P > 0.05). In the quantitative analysis, the SNR was significantly increased in the order of original, filtered, and DLR images (P < 0.001). CONCLUSION: Using DLR for near-isotropic CE-T1W MRE improved the image quality and increased the SNR.

Closed loop obstruction of small bowel: CT signs predicting successful non-surgical treatment.

PURPOSE: To clarify the computed tomography (CT) findings related to successful conservative treatments in patients with closed-loop small bowel obstruction (CL-SBO) without evidence of bowel strangulation. METHODS: Sixty-four patients (71 CT scans) diagnosed with CL-SBO by CT and received initial conservative treatments from May 2010 to August 2020 were retrospectively included. Two blinded radiologists reviewed the CT findings, including the transition zone (number, distance, and location), maximum bowel diameter, mesenteric haziness, mesenteric fluid, increased unenhanced bowel wall attenuation, decreased bowel wall enhancement, small bowel feces sign, whirl sign, bowel wall thickening, ascites, and degree of obstruction. The findings of the success and failure groups of conservative treatment were compared. Interobserver agreement was assessed for all findings. RESULTS: Among the 71 cases, conservative treatments were successful in 42 cases (59 %) but failed in 29 cases (41 %). In multivariable analyses, the distance between the transition zones (>1 cm) and low-degree obstruction were independently associated with successful conservative treatments, with odds ratios of 6.23 and 3.52, respectively. The combination of these two CT findings exhibited a specificity of 89.7 % with a positive likelihood ratio of 3.01. Interobserver agreement of the degree of obstruction and the distance between the transition zones was almost perfect (ĸ = 0.814 and 0.914, respectively). CONCLUSIONS: The distance between the transition zones (>1 cm) and low-grade obstruction are independent CT predictors of successful conservative treatments in CL-SBO patients. Initial conservative treatments are recommended for patients with both CT findings.

Imaging features of hepatocellular carcinoma in nonalcoholic fatty liver disease and nonalcoholic steatohepatitis: a systematic review and meta-analysis.

PURPOSE: To investigate the imaging features of hepatocellular carcinoma (HCC) in patients with non-alcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) through a systematic review and meta-analysis. METHODS: MEDLINE, EMBASE, and the Cochrane Library database were searched for studies providing data on imaging features of HCC in NAFLD and NASH between January 1, 2011 and July 19, 2021. Random effects models were used to calculate the pooled percentages of the three major features of arterial-phase hyperenhancement (APHE), washout, and enhancing capsule. Sensitivity analysis and subgroup analysis were performed according to underlying liver disease (NASH vs. NAFLD) and imaging modality (CT vs. MRI). RESULTS: Five studies (170 patients with 193 HCCs) were included in the analysis. The pooled percentages of APHE, washout, and enhancing capsule were 94.0% (95% confidence interval [CI] 89.1-96.7%), 72.7% (95% CI 63.3-80.4%), and 57.5% (95% CI 45.1-69.1%), respectively. The percentages of these three major features did not significantly differ between NAFLD and NASH (p ≥ 0.21). MRI showed similar pooled percentages of APHE (94.3% vs. 93.4%, p = 0.82) and washout (70.4% vs. 77.2%, p = 0.38) to CT, but a higher pooled percentage of enhancing capsule (67.1% vs. 44.7%, p = 0.02). CONCLUSION: HCC in patients with NAFLD and NASH had a similar frequency of APHE to HCC with other etiology. However, it showed a relatively low frequency of washout and enhancing capsule.

Is the Mixed Use of Magnetic Resonance Enterography and Computed Tomography Enterography Adequate for Routine Periodic Follow-Up of Bowel Inflammation in Patients with Crohn's Disease?

OBJECTIVE: Computed tomography enterography (CTE) and magnetic resonance enterography (MRE) are considered substitutes for each other for evaluating Crohn's disease (CD). However, the adequacy of mixing them for routine periodic follow-up for CD has not been established. This study aimed to compare MRE alone with the mixed use of CTE and MRE for the periodic follow-up of small bowel inflammation in patients with CD. MATERIALS AND METHODS: We retrospectively compared two non-randomized groups, each comprising 96 patients with CD. One group underwent CTE and MRE (MRE followed by CTE or vice versa) for the follow-up of CD (interval, 13-27 months [median, 22 months]), and the other group underwent MRE alone (interval, 15-26 months [median, 21 months]). However, these two groups were similar in clinical characteristics. Three independent readers from three different institutions determined whether inflammation had decreased, remained unchanged, or increased within the entire small bowel and the terminal ileum based on sequential enterography of the patients after appropriate blinding. We compared the two groups for inter-reader agreement and accuracy (terminal ileum only) using endoscopy as the reference standard for enterographic interpretation. RESULTS: The inter-reader agreement was greater in the MRE alone group for the entire small bowel (intraclass correlation coefficient [ICC]: 0.683 vs. 0.473; p = 0.005) and the terminal ileum (ICC: 0.656 vs. 0.490; p = 0.030). The interpretation accuracy was higher in the MRE alone group without statistical significance (70.9%-74.5% vs. 57.9%-64.9% in individual readers; adjusted odds ratio = 3.21; p = 0.077). CONCLUSION: The mixed use of CTE and MRE was inferior to MRE alone in terms of inter-reader reliability and could probably be less accurate than MRE alone for routine monitoring of small bowel inflammation in patients with CD. Therefore, the consistent use of MRE is favored for this purpose.

Association between Texture Analysis Parameters and Molecular Biologic KRAS Mutation in Non-Mucinous Rectal Cancer.

Purpose: To evaluate the association between magnetic resonance imaging (MRI)-based texture parameters and Kirsten rat sarcoma viral oncogene homolog (KRAS) mutation in patients with non-mucinous rectal cancer. Materials and Methods: Seventy-nine patients who had pathologically confirmed rectal non-mucinous adenocarcinoma with or without KRAS-mutation and had undergone rectal MRI were divided into a training (n = 46) and validation dataset (n = 33). A texture analysis was performed on the axial T2-weighted images. The association was statistically analyzed using the Mann-Whitney U test. To extract an optimal cut-off value for the prediction of KRAS mutation, a receiver operating characteristic curve analysis was performed. The cut-off value was verified using the validation dataset. Results: In the training dataset, skewness in the mutant group (n = 22) was significantly higher than in the wild-type group (n = 24) (0.221 ± 0.283; -0.006 ± 0.178, respectively, p = 0.003). The area under the curve of the skewness was 0.757 (95% confidence interval, 0.606 to 0.872) with a maximum accuracy of 71%, a sensitivity of 64%, and a specificity of 78%. None of the other texture parameters were associated with KRAS mutation (p > 0.05). When a cut-off value of 0.078 was applied to the validation dataset, this had an accuracy of 76%, a sensitivity of 86%, and a specificity of 68%. Conclusion: Skewness was associated with KRAS mutation in patients with non-mucinous rectal cancer.

Comparison of diagnostic performance between diffusion kurtosis imaging parameters and mono-exponential ADC for determination of clinically significant cancer in patients with prostate cancer.

PURPOSE: To compare the diagnostic performance between diffusion kurtosis imaging (DKI) parameters and mono-exponential apparent diffusion coefficient (ADC) for determination of clinically significant cancer (CSC, Gleason score (GS) ≥ 7) in patients with histologically proven prostate cancer (PCa). METHODS: A total of 92 patients (mean age: 71.5 years, range: 47-89 years) who had been diagnosed as PCa and undergone 3 T-MRI including DWI (b values, 0, 100, 1000, 2000s/mm2) were included in this study. The DKI parameters, namely apparent diffusion for non-Gaussian distribution (Dapp) and apparent kurtosis coefficient (Kapp), were calculated by dedicated software using mono-exponential and diffusion kurtosis models for quantitation. The measurement was performed for a whole tumor after segmentation, and pathologic topographic maps or systemic biopsy results served as the reference standard for segmentation. To compare the diagnostic performance of each parameter for determination of CSC, pair-wise comparison of receiver operating characteristic (ROC) curves was performed. RESULTS: The study population consisted of GS 6 (n = 18), GS 7 (n = 31), GS 8 (n = 25), GS 9 (n = 15) and GS 10 (n = 3) patients. The area under the ROC curve of Kapp (0.707, 95% CI 0.603-0.798) for discriminating CSC from non-CSC was not significantly different from those of mono-exponential ADC (0.725, 0.622-0.813, P = 0.2175) or Dapp (0.726, 0.623-0.814, P = 0.9628). Diagnostic predictive values of Kapp were estimated to a maximum accuracy of 78%, a sensitivity of 86%, and a specificity of 47%, while those of mono-exponential ADC were 75, 81, and 53%, respectively. CONCLUSION: The DKI parameters showed a diagnostic performance comparable to mono-exponential ADC for determination of CSC in patients with PCa.

Inconsistency in the use of the term "validation" in studies reporting the performance of deep learning algorithms in providing diagnosis from medical imaging.

BACKGROUND: The development of deep learning (DL) algorithms is a three-step process-training, tuning, and testing. Studies are inconsistent in the use of the term "validation", with some using it to refer to tuning and others testing, which hinders accurate delivery of information and may inadvertently exaggerate the performance of DL algorithms. We investigated the extent of inconsistency in usage of the term "validation" in studies on the accuracy of DL algorithms in providing diagnosis from medical imaging. METHODS AND FINDINGS: We analyzed the full texts of research papers cited in two recent systematic reviews. The papers were categorized according to whether the term "validation" was used to refer to tuning alone, both tuning and testing, or testing alone. We analyzed whether paper characteristics (i.e., journal category, field of study, year of print publication, journal impact factor [JIF], and nature of test data) were associated with the usage of the terminology using multivariable logistic regression analysis with generalized estimating equations. Of 201 papers published in 125 journals, 118 (58.7%), 9 (4.5%), and 74 (36.8%) used the term to refer to tuning alone, both tuning and testing, and testing alone, respectively. A weak association was noted between higher JIF and using the term to refer to testing (i.e., testing alone or both tuning and testing) instead of tuning alone (vs. JIF <5; JIF 5 to 10: adjusted odds ratio 2.11, P = 0.042; JIF >10: adjusted odds ratio 2.41, P = 0.089). Journal category, field of study, year of print publication, and nature of test data were not significantly associated with the terminology usage. CONCLUSIONS: Existing literature has a significant degree of inconsistency in using the term "validation" when referring to the steps in DL algorithm development. Efforts are needed to improve the accuracy and clarity in the terminology usage.

Deep Learning Algorithm for Automated Segmentation and Volume Measurement of the Liver and Spleen Using Portal Venous Phase Computed Tomography Images.

OBJECTIVE: Measurement of the liver and spleen volumes has clinical implications. Although computed tomography (CT) volumetry is considered to be the most reliable noninvasive method for liver and spleen volume measurement, it has limited application in clinical practice due to its time-consuming segmentation process. We aimed to develop and validate a deep learning algorithm (DLA) for fully automated liver and spleen segmentation using portal venous phase CT images in various liver conditions. MATERIALS AND METHODS: A DLA for liver and spleen segmentation was trained using a development dataset of portal venous CT images from 813 patients. Performance of the DLA was evaluated in two separate test datasets: dataset-1 which included 150 CT examinations in patients with various liver conditions (i.e., healthy liver, fatty liver, chronic liver disease, cirrhosis, and post-hepatectomy) and dataset-2 which included 50 pairs of CT examinations performed at ours and other institutions. The performance of the DLA was evaluated using the dice similarity score (DSS) for segmentation and Bland-Altman 95% limits of agreement (LOA) for measurement of the volumetric indices, which was compared with that of ground truth manual segmentation. RESULTS: In test dataset-1, the DLA achieved a mean DSS of 0.973 and 0.974 for liver and spleen segmentation, respectively, with no significant difference in DSS across different liver conditions (p = 0.60 and 0.26 for the liver and spleen, respectively). For the measurement of volumetric indices, the Bland-Altman 95% LOA was -0.17 ± 3.07% for liver volume and -0.56 ± 3.78% for spleen volume. In test dataset-2, DLA performance using CT images obtained at outside institutions and our institution was comparable for liver (DSS, 0.982 vs. 0.983; p = 0.28) and spleen (DSS, 0.969 vs. 0.968; p = 0.41) segmentation. CONCLUSION: The DLA enabled highly accurate segmentation and volume measurement of the liver and spleen using portal venous phase CT images of patients with various liver conditions.

Accuracy of contrast-enhanced ultrasound liver imaging reporting and data system: a systematic review and meta-analysis.

BACKGROUND AND AIM: After the introduction of the contrast-enhanced ultrasound Liver Imaging Reporting and Data System (CEUS LI-RADS), several studies have reported on its performance, but the reported data vary considerably. Therefore, we performed a systematic review and meta-analysis to determine the diagnostic performance of CEUS LI-RADS in patients at risk for hepatocellular carcinoma (HCC) and investigate the causes of study heterogeneity. METHODS: Original studies published until May 30, 2020, investigating the diagnostic performance of CEUS LI-RADS were identified in the MEDLINE, EMBASE, and Cochrane library databases. Study quality was assessed using the QUADAS-2 tool. Meta-analytic summary sensitivity and specificity for the diagnosis of HCC were calculated using a bivariate random-effects model. Meta-regression analysis was performed to explore the causes of study heterogeneity. RESULTS: Of the 105 articles screened, eight studies were finally analyzed (5428 hepatic observations). The summary sensitivity and specificity of CEUS LI-RADS category 5 (LR-5) for diagnosing HCC were 73% [95% confidence interval (CI) 65-79%; I2 = 93%] and 95% (95% CI 91-97%; I2 = 89%), respectively. Substantial study heterogeneity was noted in both sensitivity and specificity. Study heterogeneity was significantly associated with the proportion of cases of HCC and the type of reference standard (p ≤ 0.05). CONCLUSION: CEUS LI-RADS had high pooled specificity for diagnosing HCC but suboptimal pooled sensitivity. Substantial study heterogeneity was found, which was significantly associated with the proportion of cases of HCC and the type of reference standard.

Development and Validation of a Simple Index Based on Non-Enhanced CT and Clinical Factors for Prediction of Non-Alcoholic Fatty Liver Disease.

OBJECTIVE: A widely applicable, non-invasive screening method for non-alcoholic fatty liver disease (NAFLD) is needed. We aimed to develop and validate an index combining computed tomography (CT) and routine clinical data for screening for NAFLD in a large cohort of adults with pathologically proven NAFLD. MATERIALS AND METHODS: This retrospective study included 2218 living liver donors who had undergone liver biopsy and CT within a span of 3 days. Donors were randomized 2:1 into development and test cohorts. CTL-S was measured by subtracting splenic attenuation from hepatic attenuation on non-enhanced CT. Multivariable logistic regression analysis of the development cohort was utilized to develop a clinical-CT index predicting pathologically proven NAFLD. The diagnostic performance was evaluated by analyzing the areas under the receiver operating characteristic curve (AUC). The cutoffs for the clinical-CT index were determined for 90% sensitivity and 90% specificity in the development cohort, and their diagnostic performance was evaluated in the test cohort. RESULTS: The clinical-CT index included CTL-S, body mass index, and aspartate transaminase and triglyceride concentrations. In the test cohort, the clinical-CT index (AUC, 0.81) outperformed CTL-S (0.74; p < 0.001) and clinical indices (0.73-0.75; p < 0.001) in diagnosing NAFLD. A cutoff of ≥ 46 had a sensitivity of 89% and a specificity of 41%, whereas a cutoff of ≥ 56.5 had a sensitivity of 57% and a specificity of 89%. CONCLUSION: The clinical-CT index is more accurate than CTL-S and clinical indices alone for the diagnosis of NAFLD and may be clinically useful in screening for NAFLD.

Added value of diffusion-weighted imaging for evaluation of extramural venous invasion in patients with primary rectal cancer.

OBJECTIVE:: To evaluate the added value of diffusion-weighted imaging (DWI) to T 2 weighted imaging (T 2WI) for detection of extramural venous invasion (EMVI) in patients with primary rectal cancer. METHODS:: 79 patients (50 men, 29 females, mean age 67.4 years, range 37-87 years) who had undergone rectal MRI and subsequently received surgical resection were included. The rectal MRI consisted of T 2WI in three planes and axial DWI (b-values, 0, 1000 s mm-2). Two radiologists blinded to the pathologic results independently reviewed the T 2WI first, and then the combined T 2WI and DWI 4 weeks later. They recorded their confidence scores for EMVI on a 5-point scale (0: definitely negative and 4: definitely positive). The diagnostic performance of each reading session for each reader was compared by pairwise comparison of receiver operating characteristic curves. The area under the ROC curve (AUC) was considered as the diagnostic performance. The result of a histopathological examination served as the reference standard for EMVI. RESULTS:: For both readers, the diagnostic performance was not significantly different between the two image sets (for reader 1, AUC, 0.828 and 0.825, p = 0.9426 and for reader 2, AUC, 0.723 and 0.726, p = 0.9244, respectively). CONCLUSION:: There was no added value of DWI to T2WI for detection of EMVI in patients with primary rectal cancer. ADVANCES IN KNOWLEDGE:: High-resolution T2WI alone is sufficient to assess EMVI and a supplementary DWI has no added value in patients with primary rectal cancer.

Comparison of diagnostic performance between 1 millisievert CT enterography and half-standard dose CT enterography for evaluating active inflammation in patients with Crohn's disease.

PURPOSE: To compare the diagnostic performance of CT enterography (CTE) images obtained at 1 millisievert (mSv) and reconstructed with filtered back projection (FBP) and adaptive statistical iterative reconstruction (ASIR) with those of half-dose CTE images for the evaluation of active inflammation in patients with Crohn's disease. METHODS: Forty-six consecutive patients (mean age 29 years; range 15-59 years) with Crohn's disease underwent CTE which comprised a standard-dose scan at the enteric phase (45 s), a half-dose scan with ASIR at the portal venous phase (70 s), and 1 mSv scans with FBP and ASIR at the delayed phase (90 s) under a fixed 120 kVp and variable mAs. Two blinded readers independently recorded confidence scores for active inflammation in the ileum and terminal ileum, respectively. The diagnostic performance of each image set was compared by pairwise comparison of receiver operating characteristic curves. The established image findings on standard-dose scan and ileocolonoscopy served as the reference standard. RESULTS: A total of 92 bowel segments were analyzed. For reader 1, the diagnostic performance was increased from 1 mSv CT with FBP and 1 mSv CT with ASIR to half-dose scan with ASIR (AUC, 0.759, 0.794, and 0.845; P = 0.1429, P = 0.0107, respectively). For reader 2, there was no significant difference among the three image sets (AUC, 0.848, 0.865, and 0.845; P > 0.05, respectively). CONCLUSIONS: The diagnostic performance of 1 mSv CTE may be comparable to that of half-dose CTE.