Acute cholecystitis: predictive clinico-radiological assessment for conversion of laparoscopic cholecystectomy.

BACKGROUND: Previous studies evaluating predictive factors for the conversion from laparoscopic to open cholecystectomy have reported conflicting conclusions. PURPOSE: To create a risk assessment model to predict the conversion from laparoscopic to open cholecystectomy in patients with acute calculous cholecystitis. MATERIAL AND METHODS: A retrospective review of patients with acute calculous cholecystitis with available preoperative contrast-enhanced computed tomography (CT) findings who underwent laparoscopic cholecystectomy was performed. Forty-four parameters-including demographics, clinical history, laboratory data, and CT findings-were analyzed. RESULTS: Among the included 581 patients, conversion occurred in 113 (19%) cases. Multivariate analysis identified obesity (odd ratio [OR] 2.58, P = 0.04), history of abdominal surgery (OR 1.78, P = 0.03), and prolonged prothrombin time (OR 1.98, P = 0.03) as predictors of conversion. In preoperative CT findings, the absence of gallbladder wall enhancement (OR 3.15, P = 0.03), presence of a gallstone in the gallbladder infundibulum (OR 2.11, P = 0.04), and inflammation of the hepatic pedicle (OR 1.71, P = 0.04) were associated with conversion. Inter-observer agreement for CT study interpretation was very good (range 0.81-1.00). A model was created to calculate the risk for conversion, with an area under the receiver operating characteristic curve of 0.87. The risk for conversion, estimated based on the number of factors identified, was in the range of 5.3% (with one factor) to 86.4% (with six factors). CONCLUSION: Obesity, history of abdominal surgery, prolonged prothrombin time, absence of gallbladder wall enhancement, presence of a gallstone in the gallbladder infundibulum, and inflammation of the hepatic pedicle are associated with conversion of laparoscopic to open cholecystectomy.

Quantitative Assessment of Liver Function by Using Gadoxetic Acid-enhanced MRI: Hepatocyte Uptake Ratio.

Purpose To determine whether hepatocyte uptake ratios derived at gadoxetic acid-enhanced MRI correlate with quantitative measures of liver function and can help to identify contraindication to major hepatectomy. Materials and Methods Between August 2016 and October 2016, 50 study participants with chronic liver disease or cirrhosis underwent liver MRI at 3.0 T including T1 mapping and elastography. Liver function was quantitatively assessed by using the indocyanine green retention test (ICG R15). T1 maps were obtained by using the Look-Locker sequence before and 10 minutes after gadoxetic acid administration (0.025 mmol/kg). The relationship between ICG R15 and the following MRI parameters was evaluated: pre- and postcontrast T1 values of the liver, hepatocyte uptake ratio representing the amount of contrast media solely taken into hepatocytes, liver volume, and degree of enhancement at the common bile duct. Diagnostic performance of the hepatocyte uptake ratio to identify patients with ICG R15 greater than 20% (ie, contraindication to hepatectomy) was compared with other parameters by using areas under the receiver operating characteristic curve. Results Hepatocyte uptake ratio showed a negative correlation with ICG R15 r of -0.78 (P < .001). In participants with chronic liver disease or Child-Pugh class A, those with ICG R15 of 20% or less showed higher hepatocyte uptake ratio than those with ICG R15 greater than 20% (P < .001). Hepatocyte uptake ratios demonstrated better performance for helping to detect ICG R15 greater than 20% than did liver volume (area under the curve, 0.96 vs 0.70; P = .01). Conclusion Hepatocyte uptake ratios are negatively correlated with liver function as measured by indocyanine green retention test and provide acceptable diagnostic performance for helping to identify participants who have contraindications to major hepatectomy. © RSNA, 2018 Online supplemental material is available for this article. See also the editorial by Reeder in this issue.

Correction to: Magnetic resonance with diffusion-weighted imaging improves assessment of focal liver lesions in patients with potentially resectable pancreatic cancer on CT.

The original version of this article, published on 19 January 2018, unfortunately contained a mistake.

Preoperative MDCT Assessment of Resectability in Borderline Resectable Pancreatic Cancer: Effect of Neoadjuvant Chemoradiation Therapy.

OBJECTIVE: The purpose of this study is to evaluate the diagnostic performance of MDCT in assessing tumor resectability in patients with borderline resectable pancreatic cancers after receiving neoadjuvant chemoradiation therapy (CRT) in comparison with those undergoing upfront surgery. SUBJECTS AND METHODS: Thirty-seven patients with borderline resectable pancreatic cancers were randomly allocated to the neoadjuvant CRT group (arm 1; n = 18) or up-front surgery group (arm 2; n = 19). Three radiologists rated the likelihood of local resectability on a 5-point scale at preoperative MDCT in two separate sessions (session 1: post-CRT of arm 1, baseline of arm 2; session 2: using new imaging criteria reflecting the changes during CRT of arm 1). The AUC of each reviewer, as well as sensitivity, specificity, and accuracy based on consensus interpretation, were compared between arms and sessions. RESULTS: For local resectability (n = 30), AUC values at session 1 were 0.664, 0.669, and 0.588 for reviewers 1, 2, and 3, respectively, and were not significantly different between arms 1 (n = 15; 0.759, 0.713, and 0.593) and 2 (n = 15; 0.852, 0.685, and 0.722) (p > 0.05). In arm 1, MDCT sensitivity, specificity, accuracy were 22%, 100%, and 53%, respectively, at session 1 versus 78%, 67%, and 73%, respectively, at session 2 (p > 0.05). CONCLUSION: In patients with borderline resectable pancreatic cancers, neoadjuvant CRT did not significantly decrease the performance of MDCT for the prediction of local resectability. However, by considering post-CRT changes, such as nonprogression in tumor-vascular contact, MDCT may provide better sensitivity for locally resectable disease.

Magnetic resonance with diffusion-weighted imaging improves assessment of focal liver lesions in patients with potentially resectable pancreatic cancer on CT.

PURPOSE: To investigate added value of MRI to preoperative staging MDCT for evaluation of focal liver lesions (FLLs) in potentially resectable pancreatic ductal adenocarcinomas (PDACs). MATERIALS AND METHODS: In patients with potentially resectable PDACs after staging MDCT (n=167), characteristics of FLLs were scored as benign, indeterminate or metastases on an MDCT set and combined MDCT and MRI set by two readers, independently. Size of hepatic lesions was measured and detection rate of hepatic metastasis unsuspected by MDCT and diagnostic yield of MRI for FLLs were assessed. RESULTS: Reader-averaged figure-of-merit (FOM) of the combined set was significantly higher than that of MDCT alone (0.94 vs. 0.86, p=.028). In the negative-on-CT group, the diagnostic yield of MRI was 1.5-2.3% (2/133 and 3/133 for readers 1 and 2, respectively). In the indeterminate-on-CT group, MRI yield was 10.5-13.6% (2/19 and 3/22) and in patients with suspicious-metastasis-on-CT, 8.3-26.7% (1/12 and 4/15). All lesions with false-positive and false-negative CT findings were ≤1 cm. CONCLUSION: In potentially resectable PDACs, addition of MRI with DWI can provide significantly better diagnostic performance in characterization of focal liver lesions, especially for small-sized (≤ 1 cm) MDCT-indeterminate or suspicious metastasis lesions, aiding in determination of appropriate operation candidates. KEY POINTS: • Addition of MRI provides better diagnostic performance in characterization of liver lesions. • Combined interpretation of MRI and MDCT provided less frequent indeterminate liver lesions. • Diagnostic yield of MRI was high in CT-indeterminate or suspicious metastatic lesions. • Operation candidates can be determined with greater confidence in potentially resectable PDACs.

Preoperative tumor restaging and resectability assessment of gastric cancers after chemotherapy: diagnostic accuracy of MDCT using new staging criteria.

PURPOSE: To evaluate the diagnostic performance of preoperative MDCT for tumor restaging and determination of resectability in gastric cancers after chemotherapy using new staging criteria. METHODS: This retrospective study was approved by our institutional review board and the requirement for informed consent was waived. Thirty-seven patients with initially unresectable gastric cancers who had received chemotherapy followed by surgery were included. Two independent radiologists reviewed preoperative MDCT images to determine the TNM staging and rate the overall likelihood of resectability using a 5-point scale (5: definitely unresectable, 1: definitely resectable). New post-chemotherapy MDCT criteria do not use non-enhancing perigastric infiltrations, non-enhancing lymph nodes (LNs), and subtle remaining infiltrations after marked decrease in the size of distant metastases for T, N, and M upstaging, respectively. Discrepancies in TNM staging were resolved by a third reviewer. The diagnostic performances of MDCT were assessed using pathologic results or operation records as reference standards. RESULTS: For predicting resectability, the areas under the ROC curve were 0.885 and 0.882 (95% CIs 0.737-0.966 and 0.733-0.964) in reviewers 1 and 2, respectively, with substantial inter-reader agreement (weighted κ = 0.689). Sensitivities and specificities of MDCT for tumor restaging on a consensus review were 80.0% (4/5) and 100% (29/29) for T4b, 35.3% (6/17) and 81.3% (13/16) for N-positive, and 63.6% (7/11) and 100% (26/26) for M1, respectively. CONCLUSIONS: For gastric cancers after chemotherapy, new MDCT criteria demonstrated high specificities for T4b and M-staging and good performances to predict resectability before conversion surgery.