Differentiating between benign and malignant ampullary strictures: a prediction model using a nomogram based on CT imaging and clinical findings.

OBJECTIVES: To construct a predictive nomogram for differentiating malignant from benign ampullary strictures using contrast-enhanced computed tomography (CT) findings combined with clinical findings. METHODS: In this retrospective study, 152 patients with ampullary stricture (98 benign and 54 malignant) who underwent contrast-enhanced CT were included. Various imaging findings of the ampulla, bile duct, main pancreatic duct, and periampullary area were evaluated and clinical findings including the presence of jaundice, carbohydrate antigen 19-9 level, and history of cholecystectomy were collected. Among them, statistically significant findings were identified using univariable and multivariable logistic regression analyses. A nomogram was constructed to differentiate benign and malignant ampullary strictures and was internally validated. RESULTS: Multivariable analysis revealed that jaundice (odds ratio [OR]: 17.33, p < 0.001), presence of an ampullary mass (OR: 24.40, p < 0.001), non-similar enhancement of the ampulla to the duodenum (OR: 31.96, p = 0.003), and proportional dilatation of the bile duct (OR: 7.98, p = 0.001) were independent significant factors for predicting the malignant ampullary stricture, and were used to construct a nomogram. Among them, non-similar enhancement of the ampulla to the duodenum showed the highest OR and predictor point on the nomogram. The calibration plots showed excellent agreement between the predicted probabilities and the actual rates of malignant ampullary strictures, on internal validation. CONCLUSIONS: Combination of clinical and imaging findings could aid in predicting malignant ampullary strictures using significant findings of jaundice, presence of ampullary mass, non-similar enhancement of the ampulla to the duodenum, and proportional dilatation of the bile duct. KEY POINTS: • The presence of jaundice, ampullary mass, non-similar enhancement of the ampulla, and proportional bile duct dilatation were significant findings for predicting malignant ampullary strictures. • Non-similar enhancement of the ampulla to the duodenum was a significant feature with the highest odds ratio for differentiating benign and malignant ampullary strictures. • The nomogram constructed using contrast-enhanced computed tomography imaging and clinical findings could aid in predicting malignant ampullary strictures.

Deep learning image reconstruction algorithm for abdominal multidetector CT at different tube voltages: assessment of image quality and radiation dose in a phantom study.

OBJECTIVES: To compare the image quality and radiation dose of a deep learning image reconstruction (DLIR) algorithm compared with iterative reconstruction (IR) and filtered back projection (FBP) at different tube voltages and tube currents. MATERIALS AND METHODS: A customized body phantom was scanned at different tube voltages (120, 100, and 80 kVp) with different tube currents (200, 100, and 60 mA). The CT datasets were reconstructed with FBP, hybrid IR (30% and 50%), and DLIR (low, medium, and high levels). The reference image was set as an image taken with FBP at 120 kVp/200 mA. The image noise, contrast-to-noise ratio (CNR), sharpness, artifacts, and overall image quality were assessed in each scan both qualitatively and quantitatively. The radiation dose was also evaluated with the volume CT dose index (CTDIvol) for each dose scan. RESULTS: In qualitative and quantitative analyses, compared with reference images, low-dose CT with DLIR significantly reduced the noise and artifacts and improved the overall image quality, even with decreased sharpness (p < 0.05). Despite the reduction of image sharpness, low-dose CT with DLIR could maintain the image quality comparable to routine-dose CT with FBP, especially when using the medium strength level. CONCLUSION: The new DLIR algorithm reduced noise and artifacts and improved overall image quality, compared to FBP and hybrid IR. Despite reduced image sharpness in CT images of DLIR algorithms, low-dose CT with DLIR seems to have an overall greater potential for dose optimization. KEY POINTS: • Using deep learning image reconstruction (DLIR) algorithms, image quality was maintained even with a radiation dose reduced by approximately 70%. • DLIR algorithms yielded lower image noise, higher contrast-to-noise ratios, and higher overall image quality than FBP and hybrid IR, both subjectively and objectively. • DLIR algorithms can provide a better image quality, much better than FBP and even better than hybrid IR, while facilitating a reduction in radiation dose.

CT-based nomogram for predicting survival after R0 resection in patients with gallbladder cancer: a retrospective multicenter analysis.

OBJECTIVES: To establish a prognostic nomogram for patients undergoing R0 resection for gallbladder cancer based on preoperative CT. METHODS: A total of 151 patients (64 males, 87 females; mean age, 73.26 years) with gallbladder cancer who underwent CT and surgery with margin-negative resection were retrospectively collected at two tertiary institutions. The demographic and radiologic parameters were analyzed using univariate and multivariate Cox regression analyses to identify independent prognostic factors. The final CT-based nomogram was constructed to predict prognosis after curative resection of gallbladder cancer. Calibration curves for the survival probabilities were obtained for internal validation. RESULTS: Mass-forming type (hazard ratio [HR], 28.80), bile duct invasion (HR, 4.76), duodenal invasion (HR, 6.32), colon invasion (HR, 4.37), gallstones (HR, 0.09), and cholecystitis (HR, 2.56) were significant independent predictors for recurrence-free survival (p < .05). Mass-forming type (HR, 8.16, p < .001), bile duct invasion (HR, 2.92, p = .013), duodenal invasion (HR, 3.72, p = .012), and regional lymph node metastasis (HR, 2.07, p = .043) were independent predictors of poor cancer-specific survival (CSS) and were used to construct the nomogram. The nomogram showed a good predictive ability for the probabilities of survival on the calibration curves, and the concordance index of the model in predicting CSS was .768. CONCLUSION: Preoperative CT findings could predict the prognosis of gallbladder cancer, and the CT-based nomogram accurately predicted CSS in patients with gallbladder cancer after attempted curative resection. KEY POINTS: • Among the preoperative imaging features, mass-forming type, bile duct invasion, duodenal invasion, and regional lymph node metastasis were independent predictors of poor cancer-specific survival. • The nomogram constructed using preoperative CT findings showed a good predictive ability for the survival on calibration curves, and the concordance index of the model in predicting cancer-specific survival was 0.768.

Interobserver Variability and Diagnostic Performance of Gadoxetic Acid-enhanced MRI for Predicting Microvascular Invasion in Hepatocellular Carcinoma.

Background Accurate identification of microvascular invasion (MVI) in hepatocellular carcinoma (HCC) before treatment is critical for selecting a proper treatment strategy. Purpose To evaluate the interobserver agreement and the diagnostic performance of the MRI assessment of MVI in HCC according to the level of radiologist experience. Materials and Methods This retrospective study included 100 patients with surgically confirmed HCCs smaller than 5 cm who underwent gadoxetic acid-enhanced MRI between 2013 and 2016. Eight postfellowship radiologists (four with 7-13 years of experience [more experienced] and four with 3-6 years of experience [less experienced]) evaluated four imaging features (nonsmooth tumor margin, irregular rim-like enhancement in the arterial phase, peritumoral arterial phase hyperenhancement, peritumoral hepatobiliary phase hypointensity) and assigned the possibility of MVI. Interobserver agreement was determined by using Fleiss κ statistics according to reviewer experience and tumor size (≤3 cm vs >3 cm). With reference standards of histopathologic specimens, the diagnostic performance in the identification of MVI was assessed by using receiver operating characteristic curve analysis. Results In 100 patients (mean age, 58 years ± 10 [standard deviation]; 70 men) with 100 HCCs (mean size, 2.8 cm ± 0.9), 39 (39%) HCCs had MVI. The overall interobserver agreement was fair to moderate for the imaging features and their combinations (κ = 0.38-0.47) and MVI probability (κ = 0.41; 95% confidence interval: 0.33, 0.45). More experienced reviewers demonstrated higher agreement in MVI probability than less experienced reviewers (κ = 0.55 vs 0.36, respectively; P = .002). Diagnostic performance of each reviewer was modest for MVI prediction (area under the receiver operating characteristic curve [AUC] range, 0.60-0.74). The AUCs for the diagnosis of MVI were lower for HCCs larger than 3 cm (range, 0.55-0.69) than for those less than or equal to 3 cm (range, 0.59-0.75). Conclusion Considerable interobserver variability exists in the assessment of microvascular invasion in hepatocellular carcinoma using MRI, even for more experienced radiologists. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Tang in this issue.

Gastric cancer: development and validation of a CT-based model to predict peritoneal metastasis.

BACKGROUND: The sensitivity of computed tomography (CT) for the detection of peritoneal metastasis (PM) of advanced gastric cancer (AGC) is relatively low. PURPOSE: To develop a predictive model to improve the sensitivity of PM detection and to externally validate this model. MATERIAL AND METHODS: We analyzed data from 78 patients with PM, who had undergone preoperative CT and subsequent surgery between January 2012 and December 2014, and 101 controls to form a derivation set, retrospectively. The following CT findings were evaluated: tumor size; Bormann type 4; enlarged lymph node; indirect findings of PM (peritoneal thickening, fat stranding, plaques or nodules on the peritoneum, and ascites); and definitive findings of PM (omental cake and rectal shelf). A predictive model was created using multivariate logistic regression. Receiver operating characteristic (ROC) analyses were performed to assess the diagnostic performance of the model. The accuracy was externally validated at other hospitals on 31 patients with PM and 48 patients without PM. RESULTS: Tumor size >5.2 cm, Bormann type 4, enlarged lymph node, peritoneal plaques or nodules, and ascites were independently associated with PM. It was able to predict PM with a higher area under the ROC curve (AUC) and sensitivity than definitive findings of PM (AUC 0.903 vs. 0.647, sensitivity 92.3% vs. 38.3%). External validation confirmed the predictive power with good inter-observer agreement. CONCLUSION: The CT-driven model shows higher AUC and sensitivity for prediction of PM and may help decision-making with the aim of improving care for patients with AGC.

Spleen Stiffness Measurement Using 2-Dimensional Shear Wave Elastography: The Predictors of Measurability and the Normal Spleen Stiffness Value.

OBJECTIVES: To investigate the success rate of spleen stiffness measurement and factors that affect measurement success and to determine the spleen stiffness value of normal individuals by 2-dimensional shear wave elastography. METHODS: The spleen and liver stiffnesses of 313 consecutive patients were measured with SWE. The body mass index, abdominal wall thickness, spleen size, and liver stiffness of the patients were evaluated to identify factors associated with successful measurement of spleen stiffness. Patients were grouped by body mass index, spleen size, and liver stiffness, and the success rates and mean spleen stiffness values of the groups were compared. Independent predictors for successful spleen stiffness measurement and their cutoff values were evaluated. The mean spleen stiffness values of patients considered to have normal spleen stiffness were investigated. RESULTS: The overall success rate of spleen stiffness measurement was 52.9%. It was significantly higher in nonobese than in obese patients and in patients with splenomegaly and liver cirrhosis. The spleen stiffness value was higher in the splenomegaly group than the nonsplenomegaly group (P < .001) and increased as liver stiffness increased (P < .001). There was no significant difference in spleen stiffness values between the obese and nonobese groups. Abdominal wall thickness and splenic longitudinal diameter were identified as independent predictors of successful spleen stiffness measurement, and their cutoff values were 17.2 mm or less and greater than 9.4 cm, respectively. The mean spleen stiffness value ± SD of the normal patient group was 20.5 ± 5.4 kPa. CONCLUSIONS: The success rate of spleen stiffness measurement is lower than that of liver stiffness measurement. Spleen stiffness measurement is affected by abdominal wall thickness and spleen size.

Coefficient of Variance as Quality Criterion for Evaluation of Advanced Hepatic Fibrosis Using 2D Shear-Wave Elastography.

OBJECTIVES: To compare the diagnostic performance for advanced hepatic fibrosis measured by 2D shear-wave elastography (SWE), using either the coefficient of variance (CV) or the interquartile range divided by the median value (IQR/M) as quality criteria. METHODS: In this retrospective study, from January 2011 to December 2013, 96 patients, who underwent both liver stiffness measurement by 2D SWE and liver biopsy for hepatic fibrosis grading, were enrolled. The diagnostic performances of the CV and the IQR/M were analyzed using receiver operating characteristic curves with areas under the curves (AUCs) and were compared by Fisher's Z test, based on matching the cutoff points in an interactive dot diagram. All P values less than 0.05 were considered significant. RESULTS: When using the cutoff value IQR/M of 0.21, the matched cutoff point of CV was 20%. When a cutoff value of CV of 20% was used, the diagnostic performance for advanced hepatic fibrosis ( ≥ F3 grade) with CV of less than 20% was better than that in the group with CV greater than or equal to 20% (AUC 0.967 versus 0.786, z statistic = 2.23, P = .025), whereas when the matched cutoff value IQR/M of 0.21 showed no difference (AUC 0.918 versus 0.927, z statistic = -0.178, P = .859). CONCLUSIONS: The validity of liver stiffness measurements made by 2D SWE for assessing advanced hepatic fibrosis may be judged using CVs, and when the CV is less than 20% it can be considered "more reliable" than using IQR/M of less than 0.21.

Presence of Sarcopenia and Its Rate of Change Are Independently Associated with Long-term Mortality in Patients with Liver Cirrhosis.

BACKGROUND: Sarcopenia is associated with a poor prognosis in patients with liver cirrhosis. However, it is not known whether the rate of skeletal muscle depletion is also associated with a poor prognosis. We investigated the prognostic impact of the rate of skeletal muscle depletion in patients with liver cirrhosis. METHODS: We included retrospectively all patients with liver cirrhosis who underwent both multiple computed tomography scans and hepatic venous pressure gradient (HVPG) measurements. RESULTS: A total of 131 patients with liver cirrhosis were enrolled. The mean age of the patients was 53.7 years and alcoholic liver disease was the most common cause (61.8%). Sixty-four patients (48.9%) were diagnosed with sarcopenia. The median changes in skeletal muscle area per year (ΔSMA/y) were -0.89%. During a median follow-up period of 46.2 months (range, 3.4-87.6), 45 patients (34.4%) died. In multivariate analyses, age, Child-Pugh score, HVPG, presence of sarcopenia and ΔSMA/y were independently associated with mortality. Cumulative mortality was significantly higher in patients with ΔSMA/y < -2.4% than those with ΔSMA/y ≥ -2.4% (log-rank test, P < 0.001). CONCLUSION: Both the presence and rate of change of sarcopenia are independently associated with long-term mortality in patients with liver cirrhosis.

Safety of Percutaneous Biopsy for Hepatic Angiosarcoma: Results of a Multicenter Korean Survey.

PURPOSE: To evaluate the incidence of severe bleeding and mortality associated with percutaneous biopsy for hepatic angiosarcoma in a multicenter retrospective cohort. MATERIALS AND METHODS: A retrospective review of 33 patients with biopsy-proven hepatic angiosarcoma (29 male; median age, 57 y; age range, 24-96 y) was performed at seven tertiary academic hospitals between January 1998 and March 2015. The mean maximum tumor size was 5.5 cm (range, 1.7-20 cm). An 18-gauge automated cutting biopsy needle was used with a freehand technique in all patients who underwent ultrasonography-guided percutaneous core needle biopsy on an inpatient basis. The incidences of severe bleeding and procedure-related mortality were evaluated per Society of Interventional Radiology (SIR) guidelines. RESULTS: There was a mean of 2.8 needle passes per patient during the procedure (range, 1-6). The overall incidence of severe bleeding events (SIR grade C/D) was 9.1% (3 of 33). Two patients were managed with blood transfusion, and one patient underwent embolization for bleeding control. No other major complications were encountered. There were no cases of mortality associated with the biopsy. CONCLUSIONS: Severe bleeding was not a frequent complication after percutaneous biopsy for hepatic angiosarcoma. The majority of bleeding complications could be controlled with conservative management.

Iterative reconstruction: comparison of techniques for reduced-dose liver computed tomography following transarterial chemoembolization for hepatocellular carcinoma.

Background Adaptive statistical iterative reconstruction (ASIR) and model-based iterative reconstruction (MBIR) algorithms have the potential to reduce dose while maintaining image quality. Purpose To compare computed tomography (CT) image quality and diagnostic performance among three reconstruction techniques - ASIR, MBIR, and filtered back projection (FBP) - after transcatheter arterial chemoembolization (TACE) of hepatocellular carcinomas (HCC). Material and Methods Of 60 patients that underwent initial TACE for HCCs, half underwent dynamic liver CT with conventional scanning protocol, and the other half with dose reduction to approximately 60% of conventional exposure. All images were reconstructed using three algorithms: FBP, ASIR, and MBIR. For objective analysis, image noise and signal-to-noise ratio (SNR) were compared. For subjective analysis, three radiologists independently assessed image quality. Ability to detect viable HCCs was also evaluated. Results MBIR and ASIR produced images with less noise and higher SNR compared with FBP regardless of radiation dosage ( P < 0.017). However, in terms of subjective parameters, such as image blotchiness, artifacts, and overall quality, MBIR was inferior to FBP and ASIR ( P < 0.001). Regarding diagnostic performance, there were no significant differences among reviewers in the detection of viable HCCs depending on the reconstruction algorithm, regardless of the dose reduction protocol ( P > 0.017). Conclusion Although subjective evaluations suggest that MBIR images are of lower quality compared with FBP and ASIR regardless of radiation dosage, there were no significant differences among reconstruction algorithms in diagnosis of viable HCC after TACE.

Diagnostic Performance of Shear Wave Elastography for Predicting Esophageal Varices in Patients With Compensated Liver Cirrhosis.

OBJECTIVES: The purpose of this study was to investigate the diagnostic performance of shear wave elastography (SWE) for predicting the presence of esophageal varices and high-risk esophageal varices in patients with compensated cirrhosis and to compare it with other nonspecific predictors and according to the presence of splenomegaly. METHODS: Clinical data from 103 patients with compensated cirrhosis who underwent sonography, SWE, and endoscopy were collected consecutively. Liver stiffness was measured by SWE. Comparisons of the accuracy of prediction between groups were made by areas under the receiver operating characteristic curves (AUROCs), and regression analyses were performed for the multiple variables related to the presence of esophageal varices and high-risk varices. RESULTS: The optimal cutoff values for predicting the presence of esophageal varices and high-risk varices were 13.9 and 16.1 kPa, respectively. The AUROC of liver stiffness for prediction of esophageal varices was significantly higher than the AUROCs of platelet count, spleen diameter, and platelet count/spleen diameter ratio (P = .025; P = .001; P = .027). For predicting esophageal varices in patients without splenomegaly, the AUROC of liver stiffness was higher than that of the platelet count/spleen diameter ratio. In multivariate logistic regression analysis, liver stiffness and the platelet count/spleen diameter ratio were independent predictors of esophageal varices (P < .001; P = .038). For the presence of high-risk varices, only liver stiffness was a statistically significant independent predictor (P = .012). CONCLUSIONS: In patients with compensated cirrhosis, liver stiffness measured by SWE is a new effective noninvasive diagnostic tool for predicting the presence of esophageal varices. It is more accurate than the platelet count/spleen diameter ratio, especially in patients without splenomegaly. In addition, the SWE value was the only effective independent factor for predicting high-risk esophageal varices.

Hilar cholangiocarcinoma: value of adding DW imaging to gadoxetic acid-enhanced MR imaging with MR cholangiopancreatography for preoperative evaluation.

PURPOSE: To assess the benefit of adding diffusion-weighted (DW) imaging to gadoxetic acid-enhanced magnetic resonance (MR) imaging and MR cholangiopancreatography in the preoperative evaluation of hilar cholangiocarcinoma. MATERIALS AND METHODS: The institutional review board approved this retrospective study and waived the requirement for informed consent. The study included 52 patients (36 men, 16 women; mean age, 63.4 years) with surgically confirmed hilar cholangiocarcinoma who underwent gadoxetic acid-enhanced MR imaging and DW imaging at 3.0 T between August 2010 and December 2011. Two observers independently reviewed two image sets--a gadoxetic acid set, including images from MR cholangiopancreatography, and a combined gadoxetic acid set and DW imaging set--to evaluate the tumor involvement of each biliary confluence and vascular and liver invasion by using receiver operating characteristic (ROC) curve analysis. RESULTS: For each observer, area under the ROC curve (Az) values for tumor involvement of the biliary confluence were 0.965 and 0.957 for the gadoxetic acid set and 0.980 and 0.975 for the combined set, respectively (P > .05). For detecting 105 biliary confluences with tumor involvement, the sensitivities with the combined set (97.1% [102 of 105] and 98.1% [103 of 105]) were higher than those with the gadoxetic acid set (91.4% [96 of 105] for both observers) (P = .029 and P = .016), although the specificities were similar with both image sets (P > .05). For the detection of liver invasion, the combined set (75.0% [15 of 20] for both observers) yielded better sensitivity than the gadoxetic acid set (50.0% [10 of 20] and 45.0% [nine of 20]) (P = .016 and P = .031). For evaluation of vascular invasion, the two image sets showed similar diagnostic performance. CONCLUSION: In the preoperative evaluation of hilar cholangiocarcinoma, the addition of DW imaging to gadoxetic acid-enhanced MR imaging could improve sensitivity in the evaluation of tumor extent along the bile duct and liver invasion.

Infiltrative hepatocellular carcinoma on gadoxetic acid-enhanced and diffusion-weighted MRI at 3.0T.

PURPOSE: To determine imaging features of infiltrative hepatocellular carcinoma (HCC) on 3T magnetic resonance imaging (MRI) including gadoxetic acid-enhanced and diffusion-weighted imaging (DWI). MATERIALS AND METHODS: Eighteen patients with infiltrative HCC underwent liver MRI that consisted of T1- and T2-weighted image (T2WI), gadoxetic acid-enhanced arterial, portal, 3-min late and 20-min hepatobiliary phase (HBP), and DWI. Two reviewers evaluated in consensus tumor characteristics and lesion conspicuity using a 4-point scale. The tumor-to-liver contrast ratio was also measured. RESULTS: Most of the tumors (n = 16, 88.9%) were seen as irregular permeative masses (4.0-23.0 cm, mean 10.5 cm in diameter) and the remaining two as poorly defined amorphous infiltration among thrombosed portal veins. Internal reticulation within the tumor was characteristic and was most frequently observed on 3-min late phase (n = 18), followed by HBP (n = 15). Tumor conspicuity and tumor-to-liver contrast ratio was highest with b-800 DWI, which was significantly higher than those of other images (P < 0.05). CONCLUSION: DWI provides the highest conspicuity for infiltrative HCC compared to unenhanced T1- and T2WI and gadoxetic acid-enhanced MRI. The gadoxetic acid-enhanced 3-min late image is useful in characterizing infiltrative HCC, as it clearly depicts internal reticulation in all tumors.

Mistargeting after fusion imaging-guided percutaneous radiofrequency ablation of hepatocellular carcinomas.

PURPOSE: To evaluate the incidence and causes of mistargeting after fusion imaging-guided percutaneous radiofrequency (RF) ablation of hepatocellular carcinomas (HCCs). MATERIALS AND METHODS: Between September 2011 and March 2013, 955 HCCs in 732 patients were treated with percutaneous RF ablation. Among them, ablation of 551 HCCs was accomplished under fusion imaging guidance, and seven mistargetings were noted in seven patients (male-to-female ratio = 6:1; mean age, 60.1 y; range, 47-73 y). The incidence of mistargeting and the cause of liver disease in the patients with mistargeting were evaluated. The causes of mistargeting were assessed according to the following classification: small size of HCC, subcapsular location, subphrenic location, confusion with pseudolesions, poor conspicuity of HCC, poor sonographic window, and poor electrode path. RESULTS: The incidence of mistargeting after fusion imaging-guided RF ablation was 1.3% (7 of 551). All patients with mistargeting were hepatitis B virus carriers. The most common cause of mistargeting was the small size of HCC (100%; 7 of 7), followed by confusion with surrounding pseudolesions (85.7%; 6 of 7), subcapsular (71.4%; 5 of 7) and subphrenic locations (71.4%; 5 of 7), poor conspicuity of the HCC (71.4%; 6 of 7), poor sonographic window (28.6%; 2 of 7), and poor electrode path (28.6%; 2 of 7). CONCLUSIONS: The incidence of mistargeting after fusion imaging-guided RF ablation was 1.3%. The most common cause of mistargeting was the small size of HCC, followed by confusion with surrounding pseudolesions, subcapsular and subphrenic locations, and poor conspicuity of the HCC.

Added value of diffusion-weighted MRI for evaluating viable tumor of hepatocellular carcinomas treated with radiotherapy in patients with chronic liver disease.

OBJECTIVE: The purpose of this article is to evaluate the added value of diffusion-weighted imaging (DWI) to the diagnostic performance of conventional MRI in diagnosing viable hepatocellular carcinoma (HCC) tumors treated with radiotherapy in patients with chronic liver disease. MATERIALS AND METHODS: Twenty-nine patients with viable tumor and 35 patients without viable tumor were enrolled. We assessed the signal intensity of viable tumor compared with irradiated liver on MRI and DWI. Signal intensity ratios and apparent diffusion coefficient (ADC) ratios of viable tumor to nonirradiated liver were also assessed on DWI with ADC maps. Two observers reviewed conventional MRI and combined MRI and DWI and rated them using a 5-point scale. Diagnostic performance was evaluated using a receiver operating characteristic (ROC) curve. RESULTS: Viable tumors showed hyperintensity on T2-weighted and arterial phase images (16/29 [55.2%]) and hypointensity on portal (22/29 [75.9%]), 3-minute late (19/29 [65.5%]), and hepatobiliary phase (23/29 [79.3%]) images. Twenty-seven (93.1%) viable tumors showed hyperintensity on DWI and hypointensity on ADC maps. Mean signal intensity ratios and ADC ratios of viable tumor on DWI with ADC maps were significantly higher and lower than those of irradiated liver. Diagnostic performance (area under the ROC curve) improved significantly after adding DWI, and interobserver agreement was moderate for conventional MRI (κ = 0.450) and good after adding DWI (κ = 0.748). CONCLUSION: Adding DWI to conventional MRI can improve the detection of viable HCC tumors treated with radiotherapy compared to conventional MRI alone.

Value of diffusion-weighted MRI for differentiating malignant from benign intraductal papillary mucinous neoplasms of the pancreas.

OBJECTIVE: The purpose of this study was to evaluate whether the use of diffusion-weighted MRI (DWI) increases diagnostic accuracy in the differentiation of malignant from benign intraductal papillary mucinous neoplasms (IPMNs) of the pancreas over the accuracy of contrast-enhanced MRI with MRCP. MATERIALS AND METHODS: A total of 61 patients with surgically resected IPMNs (19 malignant, 42 benign) who underwent gadoxetic acid-enhanced MRI, DWI, and MRCP were included. Two blinded observers evaluated two image sets, that is, conventional MRI with MRCP images versus combined conventional MRI with MRCP and DW images, and scored their confidence for malignancy of IPMNs. Qualitative analyses of the IPMNs were also conducted. Diagnostic performance (ROC curve analysis), accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were evaluated. The Fisher exact test was used to compare groups. RESULTS: The diagnostic performance (area under the ROC curve [Az]) with respect to predicting malignancy of IPMNs improved significantly for both observers after additional review of DW images (p < 0.05). The diagnostic accuracy, sensitivity, specificity, PPV, and NPV of combined conventional and DW images were higher than those of conventional MR images alone. Diffusion restriction was more often present in malignant IPMNs (78.9%) than in benign IPMNs (16.7%) (p < 0.001) with excellent interobserver agreement (ĸ = 0.965). CONCLUSION: Compared with conventional MRI alone, adding DWI to conventional MRI improves diagnostic accuracy with increased specificity for differentiating malignant from benign IPMNs of the pancreas.

Sarcopenia as a useful predictor for long-term mortality in cirrhotic patients with ascites.

This study aimed to assess and compare sarcopenia with other prognostic factors for predicting long-term mortality in cirrhotic patients with ascites. Clinical data of 65 among 89 patients with measurement of all parameters were consecutively collected. Sarcopenia was evaluated as right psoas muscle thickness measurement divided by height (PMTH) (mm/m). During a mean follow-up of 20 (range: 1-49) months, 19 (29.2%) of 65 patients died. The values of the area under the receiver operating characteristics curve (AUROC) of Child-Pugh score, Model for End-Stage Liver Disease (MELD) score, MELD-Na, and PMTH for predicting 1-yr mortality were 0.777 (95% CI, 0.635-0.883), 0.769 (95% CI, 0.627-0.877), 0.800 (95% CI, 0.661-0.900), and 0.833 (95% CI, 0.699-0.924), whereas hepatic venous pressure gradient was not significant (AUROC, 0.695; 95% CI. 0.547-0.818, P=0.053). The differences between PMTH and other prognostic variables were not significant (all P>0.05). The best cut-off value of PMTH to predict long-term mortality was 14 mm/m. The mortality rates at 1-yr and 2-yr with PMTH>14 mm/m vs. PMTH≤14 mm/m were 2.6% and 15.2% vs. 41.6% and 66.8%, respectively (P<0.001). The mortality in cirrhotic patients with PMTH≤14 mm/m was higher than those with PMTH>14 mm/m (HR, 5.398; 95% CI, 2.111-13.800, P<0.001). In conclusion, sarcopenia, evaluated by PMTH, is an independent useful predictor for long-term mortality in cirrhotic patients with ascites.

Differentiation of malignant from benign ampullary strictures: A prediction nomogram based on MR imaging and clinical findings.

PURPOSE: To construct a predictive nomogram based on contrast-enhanced magnetic resonance imaging (MRI) and clinical findings for differentiating malignant from benign ampullary strictures. METHOD: In this retrospective study, 76 patients with ampullary strictures (51 benign and 25 malignant) who underwent contrast-enhanced MRI were enrolled. Imaging findings were evaluated independently by two abdominal radiologists who reached consensus. Clinical findings were also collected. Significant findings for malignant ampullary strictures were assessed by univariable and multivariable logistic regression analyses. Based on the results of multivariable analysis, a nomogram to differentiate malignant from benign ampullary strictures was developed and internally validated. RESULTS: In multivariable analysis, presence of an ampullary mass (odds ratio [OR]: 8.42, p = 0.047), bulging ampulla (OR: 8.32, p = 0.033), diffusion restriction of the ampulla (OR: 42.76, p = 0.004) on MRI, and jaundice (OR: 12.41, p = 0.019) were significant predictors of malignant ampullary strictures. A predictive nomogram was constructed using these findings. Among them, diffusion restriction of the ampulla showed the highest OR and predictor score on the nomogram. The calibration plots for internal validation achieved strong agreement between the predicted probabilities and the actual rates of malignant ampullary strictures. CONCLUSION: A combination of significant contrast-enhanced MRI and clinical findings of ampullary mass, bulging ampulla, diffusion restriction of the ampulla, and jaundice may be useful in the prediction of malignant ampullary stricture.

Local ablation for hepatocellular carcinoma: 2024 expert consensus-based practical recommendation of the Korean Liver Cancer Association.

Local ablation for hepatocellular carcinoma (HCC), a non-surgical option that directly targets and destroys tumor cells, has advanced significantly since the 1990s. Therapies with different energy sources, such as radiofrequency ablation, microwave ablation, and cryoablation, employ different mechanisms to induce tumor necrosis. The precision, safety, and effectiveness of these therapies have increased with advances in guiding technologies and device improvements. Consequently, local ablation has become the firstline treatment for early-stage HCC. The lack of organized evidence and expert opinions regarding patient selection, pre-procedure preparation, procedural methods, swift post-treatment evaluation, and follow-up has resulted in clinicians following varied practices. Therefore, an expert consensus-based practical recommendation for local ablation was developed by a group of experts in radiology and hepatology from the Research Committee of the Korean Liver Cancer Association in collaboration with the Korean Society of Image-guided Tumor Ablation to provide useful information and guidance for performing local ablation and for the pre- and posttreatment management of patients.

Local Ablation for Hepatocellular Carcinoma: 2024 Expert Consensus-Based Practical Recommendations of the Korean Liver Cancer Association.

Local ablation for hepatocellular carcinoma (HCC), a non-surgical option that directly targets and destroys tumor cells, has advanced significantly since the 1990s. Therapies with different energy sources, such as radiofrequency ablation, microwave ablation, and cryoablation, employ different mechanisms to induce tumor necrosis. The precision, safety, and effectiveness of these therapies have increased with advances in guiding technologies and device improvements. Consequently, local ablation has become the first-line treatment for early-stage HCC. The lack of organized evidence and expert opinions regarding patient selection, pre-procedure preparation, procedural methods, swift post-treatment evaluation, and follow-up has resulted in clinicians following varied practices. Therefore, an expert consensus-based practical recommendation for local ablation was developed by a group of experts in radiology and hepatology from the Research Committee of the Korean Liver Cancer Association in collaboration with the Korean Society of Image-guided Tumor Ablation to provide useful information and guidance for performing local ablation and for the pre- and post-treatment management of patients.