Breast Pseudoaneurysm in a Woman after Core Biopsy: Intravascular Glue Embolization.

Core needle biopsy of breast masses is a common procedure for tissue diagnosis of breast lesions. The incidence of complications is low, with pseudoaneurysm (PA) after core biopsy has been described in the literature, and the subsequent need for surgical management. Ultrasonography is the most common modality used for not only diagnosis but also treatment of a PA. Color Doppler images show a heterogeneous echoic lesion with whirling flow inside of the lesion. We describe a patient whose breast PA that developed after core needle biopsy was successfully treated with sonographically-guided intravascular glue embolization.

Comparison of Diagnostic Performance and Confidence between Contrast-Enhanced Computed Tomography Scan and Non-Contrast-Enhanced Computed Tomography Plus Abdomen Ultrasound for Hepatic Metastasis in Patients with Breast Cancer.

Background: The purpose of this study was to compare the performance between noncontrast-enhanced computed tomography (NECT) plus abdominal ultrasound (US) (NECT + US) with contrast-enhanced computed tomography (CECT) for the detection of hepatic metastasis in breast cancer patient with postsurgical follow-up. Methods: A total of 1470 patients without already diagnosed hepatic metastasis were included. All patients underwent US and multiphase CECT including the NECT. Independent reviewers analyzed images obtained in four settings, namely, abdominal US, NECT, NECT + US, and CECT and recorded liver metastases using a 5-grade scale of diagnostic confidence. Sensitivity, specificity (diagnostic performance), and area under the receiver operating characteristic curve (AUC, diagnostic confidence) were calculated. Interoperator agreement was calculated using the kappa test. Results: Reference standards revealed no metastases in 1108/1470 patients, and metastasis was detected in 362/1470 patients. Abdominal US (P < 0.01) and NECT (P = 0.01) significantly differed from CECT, but NECT + US did not significantly differ from CECT in terms of sensitivity (P = 0.09), specificity (P = 0.5), and AUC (P = 0.43). After an additional review of abdominal US, readers changed the diagnostic confidence scores of 106 metastatic lesions diagnosed using NECT. Interobserver agreements were good or very good in all four settings. Additional review of abdominal US with NECT allowed a change in the therapeutic plan of 108 patients. Conclusion: Abdominal US + NECT showed better diagnostic performance for the detection of hepatic metastases than did NECT alone; its diagnostic performance and confidence were similar to those of CECT.

Prediction of tumor recurrence and poor survival of ampullary adenocarcinoma using preoperative clinical and CT findings.

OBJECTIVES: To predict poor survival and tumor recurrence in patients with ampullary adenocarcinoma using preoperative clinical and CT findings. MATERIALS AND METHODS: A total of 216 patients with ampullary adenocarcinoma who underwent preoperative CT and surgery were retrospectively included. CT was assessed by two radiologists. Clinical and histopathological characteristics including histologic subtypes were investigated. A Cox proportional hazard model and the Kaplan-Meier method were used to identify disease-free survival (DFS) and overall survival (OS). A nomogram was created based on the multivariate analysis. The optimal cutoff size of the tumor was evaluated and validated by internal cross validation. RESULTS: The median OS was 62.8 ± 37.9, and the median DFS was 54.3 ± 41.2 months. For OS, tumor size (hazard ratio [HR] 2.79, p < 0.001), papillary bulging (HR 0.63, p = 0.049), organ invasion on CT (HR 1.92, p = 0.04), male sex (HR 1.59, p = 0.046), elevated CA 19-9 (HR 1.92, p = 0.01), pT stage (HR 2.45, p = 0.001), and pN stage (HR 3.04, p < 0.001) were important predictors of survival. In terms of recurrence, tumor size (HR 2.37, p = 0.04), pT stage (HR 1.76, p = 0.03), pN stage (HR 2.23, p = 0.001), and histologic differentiation (HR 4.31, p = 0.008) were important predictors of recurrence. In terms of tumor size on CT, 2.65 cm and 3.15 cm were significant cutoff values for poor OS and RFS (p < 0.001). CONCLUSION: Preoperative clinical and CT findings were useful to predict the outcomes of ampullary adenocarcinoma. In particular, tumor size, papillary bulging, organ invasion on CT, male sex, and elevated CA 19-9 were important predictors of poor survival after surgery. KEY POINTS: • Clinical staging based on preoperative clinical information and CT findings can be useful to predict the prognosis of ampullary adenocarcinoma patients. • In terms of survival, tumor size (HR 2.79), papillary bulging (HR 0.63), organ invasion on CT (HR 1.92), male sex (HR 1.59), and elevated CA 19-9 (HR 1.92) were important clinical predictors of poor survival. • Tumor size on CT was of special importance for both poor overall survival and disease-free survival, with optimal cutoff values of 2.65 cm and 3.15 cm, respectively (p < 0.001).

LI-RADS treatment response categorization on gadoxetic acid-enhanced MRI: diagnostic performance compared to mRECIST and added value of ancillary features.

OBJECTIVES: This study was conducted in order to assess the performance of the Liver Imaging Reporting and Data System (LI-RADS) treatment response (TR) (LR-TR) categorization on gadoxetic acid-enhanced MRI (Gd-EOB-MRI) for detecting viable tumors in hepatocellular carcinoma (HCC) treated with locoregional treatment (LRT) and to investigate the added value of ancillary features (AFs) to conventional enhancement-based criteria. METHODS: This retrospective study included 183 patients with Gd-EOB-MRI after LRT for HCC and appropriate reference standards for tumor viability (84 viable and 99 nonviable). Two independent radiologists assigned per-lesion mRECIST and TR categories (TR-nonviable, TR-equivocal, or TR-viable) according to the LR-TR algorithm and modified LR-TR algorithms including mLR-TR(TP) allowing transitional phase (TP) washout and mLR-TR(AF) allowing category adjustment by applying AFs. Diagnostic performances of imaging criteria were compared using the Cochran's Q test with post hoc analysis. RESULTS: For detecting viable tumors, LR-TR-viable resulted in sensitivities of 64.5%/39.3% and specificities of 98.0%/98.0% in reviewers 1/2. In comparison to LR-TR-viable, mRECIST-viable, mLR-TR(TP)-viable, and mLR-TR(AF)-viable showed significantly higher sensitivities (92.9%/94.0%, 77.4%/56.6%, and 86.9%/83.3% in reviewers 1/2) (ps < 0.001). The specificity of mRECIST-viable (73.7%/62.6%) was significantly lower than that of LR-TR-viable (ps < 0.001), while those of mLR-TR(TP)-viable and mLR-TR(AF)-viable were greater than 95% (98.0%/96.0% and 97.0%/96.0%), statistically equivalent to LR-TR-viable (ps > 0.05). TR-equivocal was least assigned on mLR-TR(AF) (1.1%/7.7%) than LR-TR (15.8%/32.2%) or mLR-TR(TP) (6.6%/23.5%) in both reviewers. CONCLUSION: The LR-TR algorithm on Gd-EOB-MRI provides a specific diagnosis of viable tumor but with limited sensitivity. By applying AFs in the category adjustment, more sensitive and confident diagnosis can be achieved without significant loss of specificity. KEY POINTS: • The LI-RADS treatment response (LR-TR) algorithm on Gd-EOB-MRI provides a highly specific diagnosis of viable HCC but with limited sensitivity. • The inferior sensitivity of LR-TR-viable category to that of mRECIST can be improved by applying ancillary features in the category adjustment.

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.

Comparison of submillisievert CT with standard-dose CT for urolithiasis.

BACKGROUND: Patients with renal stones receive multiple computed tomography (CT) examinations. We investigated whether submillisievert (sub-mSv) CT for stone detection could reduce radiation dose at exposure levels comparable to kidney, ureter, and bladder (KUB) radiography. PURPOSE: To evaluate the radiation dose exposure, diagnostic performance, and image quality of sub-mSv non-contrast CT using advanced modelled iterative reconstruction algorithm with spectral filtration for the detection of urolithiasis. MATERIAL AND METHODS: A total of 145 consecutive patients underwent non-contrast CT using a third-generation dual-source scanner to obtain two datasets, i.e. 16.7% (sub-mSv CT, tube detector A) and 100% (standard-dose CT, combination of tube detector A and B) tube loads with spectral filtration. The performance of sub-mSv CT for the detection of stones was analyzed by two readers and compared with that of standard-dose CT. Image quality was measured subjectively and objectively. RESULTS: In total, 171 stones were detected in 79 patients. The mean effective radiation doses of sub-mSv CT was 0.3 mSv. The sensitivity and specificity values for diagnosis of stones measuring ≥3 mm was 95.1% and 100% for sub-mSv CT. The sensitivity and specificity for all stone detection was 74.9% and 97.8%, respectivey, for sub-mSv CT. The image quality was lower for sub-mSv CT than for standard-dose CT (P < 0.01). CONCLUSION: Sub-mSv CT can be achieved with radiation doses close to KUB radiography. Sub-mSv CT with spectral filtration can be used to detect stones measuring ≥3 mm and be used as a follow-up imaging modality as an alternative to KUB radiography.

LI-RADS Version 2017 versus Version 2018: Diagnosis of Hepatocellular Carcinoma on Gadoxetate Disodium-enhanced MRI.

Background Few studies have reported on the diagnostic performance of Liver Imaging Reporting and Data System (LI-RADS) LR-5 or LR-5 V in the diagnosis of hepatocellular carcinoma (HCC) using MRI with gadoxetate disodium. Purpose To determine the diagnostic performance of LI-RADS version 2018 (hereafter, v2018) on gadoxetate disodium-enhanced MRI in comparison with LI-RADS version 2017 (hereafter, v2017) for the diagnosis of HCC in patients with cirrhosis or chronic hepatitis B viral infection or at high risk for HCC. Materials and Methods This retrospective study between January 2013 and October 2015 evaluated consecutive patients at high risk for HCC who had at least one observation of 10 mm or greater on gadoxetate disodium-enhanced MRI and no history of previous treatment for hepatic lesions. MRI features were reviewed by three radiologists. Observations were categorized according to LI-RADS v2018 and LI-RADS v2017. Per-observation sensitivity and specificity of LR-5 using LI-RADS v2017 and v2018 were compared using generalized estimating equation models. Results A total of 422 observations, including 234 HCCs confirmed by results of pathologic examination in 387 patients (305 men and 82 women; mean age ± standard deviation, 59 years ± 10), were included. In all observations, LI-RADS v2018 provided higher sensitivity than LI-RADS v2017 (81% [189 of 234] vs 68% [160 of 234], respectively; P < .001). In small observations (10-19 mm), LI-RADS v2018 yielded much higher sensitivity than LI-RADS v2017 (76% [34 of 45] vs 11% [five of 45], respectively; P < .001) with relatively little impairment of specificity (94% [121 of 128] vs 99% [127 of 128], respectively; P = .013). Conclusion Updated LR-5 criteria of Liver Imaging Reporting and Data System (LI-RADS) version 2018 on gadoxetate disodium-enhanced MRI can improve sensitivity in the diagnosis of small hepatocellular carcinomas (10-19 mm) with only slight impairment in specificity compared with the criteria of LI-RADS version 2017. © RSNA, 2019 Online supplemental material is available for this article.

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.

Preoperative CT Classification of the Resectability of Pancreatic Cancer: Interobserver Agreement.

Background Accurate assessment of local resectability of pancreatic cancer at initial workup is critical to determine the most appropriate management strategy among up-front operation, neoadjuvant treatment, or palliative treatment. Purpose To investigate the interobserver agreement of the preoperative CT classification of the local resectability of pancreatic cancer and to determine if radiologist experience level impacts evaluation, and to evaluate the reader performance in assessing resectability at CT in a subset of patients with a reference standard for local resectability. Materials and Methods This retrospective study was composed of patients with pathologic-analysis-confirmed pancreatic cancers between January 2013 and December 2014 who underwent baseline multiphasic contrast agent-enhanced CT. Eight board-certified radiologists with different levels of experience (more experienced, ≥6 years, n = 4; less experienced, 1st- or 2nd-year fellows, n = 4) reviewed the CT images and classified cancers as resectable, borderline resectable, or unresectable. Interobserver agreements were determined for all reviewers and subgroups of reviewers stratified according to experience (more vs less) by using Fleiss κ statistics. In patients with reference standards for local resectability, diagnostic performances of each reviewer were assessed by using receiver operating characteristic curve analysis. Results There were 110 patients (mean age, 61 years ± 11; 60 men) who were evaluated. Overall interobserver agreements were moderate for resectability classification (κ = 0.48; 95% confidence interval: 0.45, 0.50). Only 30.0% of patients (33 of 110) were given the same resectability classification from all reviewers. More experienced reviewers demonstrated higher agreement in category assignments than less experienced reviewers (κ = 0.55 [95% confidence interval: 0.50, 0.60] vs 0.43 [95% confidence interval: 0.38, 0.49], respectively). For prediction at CT of margin-negative (ie, R0) resections (n = 82), areas under the receiver operating characteristic curve of all reviewers were greater than 0.80 (range, 0.83-0.96). However, borderline resectable cancers showed diverse R0 rates ranging from 0% to 74% depending on the reviewers. Conclusion Considerable interobserver variability exists in the assignment at CT of the local resectability of pancreatic cancer, even among experienced radiologists. © RSNA, 2019 Online supplemental material is available for this article.

Natural History of Gastric Cancer: Observational Study of Gastric Cancer Patients Not Treated During Follow-Up.

BACKGROUND: Understanding the natural progression of untreated gastric cancer is critical for determining the disease prognosis as well as treatment options and timing. The aim of this study is to analyze the natural history of gastric cancer. PATIENTS AND METHODS: We included patients with gastric cancer who had not received any treatment and were staged using endoscopy/endoscopic ultrasonography and computed tomography on at least two follow-up visits during intervals of nontreatment. Tumor volumes were also measured in addition to the staging. Survival of each stage at diagnosis was also analyzed. RESULTS: A total of 101 patients were included. The mean follow-up period was 35.1 ± 34.4 months. The gastric cancer doubling time was 11.8 months for T1 and 6.2 months for T4. The progression time from early gastric cancer to advanced gastric cancer was 34 months. It decreased as the stages advanced: from 34 months between tumor-nodes-metastasis stage I and II to 1.8 months between stage III and IV. No variable was identified as a risk factor for cancer progression. The 5-year survival rates of untreated patients were 46.2% in stage I and 0% in stage II, stage III, and stage IV. CONCLUSIONS: The progression and doubling times of gastric cancer shorten as the stages advance. Objective data reported in this study can be a critical factor in determining treatment timing and screening interval.

CT reconstruction algorithms affect histogram and texture analysis: evidence for liver parenchyma, focal solid liver lesions, and renal cysts.

PURPOSE: To determine the effects of different reconstruction algorithms on histogram and texture features in different targets. MATERIALS AND METHODS: Among 3620 patients, 480 had normal liver parenchyma, 494 had focal solid liver lesions (metastases = 259; hepatocellular carcinoma = 99; hemangioma = 78; abscess = 32; and cholangiocarcinoma = 26), and 488 had renal cysts. CT images were reconstructed with filtered back-projection (FBP), hybrid iterative reconstruction (HIR), and iterative model reconstruction (IMR) algorithms. Computerized histogram and texture analyses were performed by extracting 11 features. RESULTS: Different reconstruction algorithms had distinct, significant effects. IMR had a greater effect than HIR. For instance, IMR had a significant effect on five features of liver parenchyma, nine features of focal liver lesions, and four features of renal cysts on portal-phase scans and four, eight, and four features, respectively, on precontrast scans (p < 0.05). Meanwhile, different algorithms had a greater effect on focal liver lesions (six in HIR and nine in IMR on portal-phase, three in HIR, and eight in IMR on precontrast scans) than on liver parenchyma or cysts. The mean attenuation and standard deviation were not affected by the reconstruction algorithm (p > .05). Most parameters showed good or excellent intra- and interobserver agreement, with intraclass correlation coefficients ranging from 0.634 to 0.972. CONCLUSIONS: Different reconstruction algorithms affect histogram and texture features. Reconstruction algorithms showed stronger effects in focal liver lesions than in liver parenchyma or renal cysts. KEY POINTS: • Imaging heterogeneities influenced the quantification of image features. • Different reconstruction algorithms had a significant effect on histogram and texture features. • Solid liver lesions were more affected than liver parenchyma or cysts.

CT prediction of resectability and prognosis in patients with pancreatic ductal adenocarcinoma after neoadjuvant treatment using image findings and texture analysis.

OBJECTIVES: To assess utility of CT findings and texture analysis for predicting the resectability and prognosis in patients after neoadjuvant therapy for pancreatic ductal adenocarcinoma (PDAC). MATERIALS AND METHODS: Among 308 patients, 45 with PDAC underwent neoadjuvant therapy (concurrent-chemoradiation-therapy, CCRT, n = 27 and chemotherapy, ChoT, n = 18) before surgery were included. All underwent baseline and preoperative CT. Two reviewers assessed CT findings and resectability. We analyzed relationship between CT resectability and residual tumor. CT texture values obtained by subtracting preoperative from baseline CT were analyzed using multivariate Cox/logistic regression analysis to identify significant parameters predicting resectability and prognosis. RESULTS: There were 30 patients without residual tumor (CCRT, n = 20; ChoT, n = 10) and 15 with residual tumor (CCRT, n = 7; ChoT, n = 8). Considering borderline as resectable was more accurate for R0 resectability than considering borderline as unresectable (68.9% vs 55.6% and 51.1%, p < 0.001). Particularly, neoadjuvant CCRT provided better accuracy than that in (p < 0.001). In CT texture analysis, higher subtracted entropy (cut-off: 0.03, HR 0.159, p = 0.005) and lower subtracted GLCM entropy (cut-off: -0.35, HR 10.235, p = 0.036) are important parameters for prediction of longer overall survival. CONCLUSION: CT findings with texture analysis can be useful for predicting a patient's outcome, including resectability and prognosis, after neoadjuvant therapy for PDAC. KEY POINTS: • Considering borderline resectable tumor as resectable have better accuracy for resectability. • Considering borderline as resectable, CCRT-patients have better resectability accuracy than chemotherapy-patients. • Higher subtracted entropy and lower subtracted GLCM entropy are predictors of favorable outcome.

Optimal CT protocol for the diagnosis of active bleeding in abdominal trauma patients.

OBJECTIVES: The aim of this study is to compare the radiologic diagnostic performance of arterial phase, portal phase and combined phase computed tomography (CT) for traumatic abdominal injury. In addition, this study is attempted to decrease lifetime attributable risks (LARs) of cancer due to radiation exposure by using optimal CT protocol. MATERIALS AND METHODS: A total of 114 consecutive patients with a traumatic abdominal injury and an abdominal hematoma on CT were enrolled at a single tertiary regional trauma center between January 2016 and March 2017. Each CT protocol set was independently reviewed by three radiologists, and the diagnostic performance of all three CT phases were compared with regard to the capability to detect active bleeding, contained vascular injuries, and organ injuries. Additionally, LARs for cancer incidence and mortality were calculated using dose-length product values, for each phase of CT. RESULTS: The pooled area under the receiver operating characteristic curves for the diagnosis of active bleeding, contained vascular injuries, and organ injuries ranged from 0.910 to 0.922, 0.643 to 0.723, and 0.948 to 0.915 for arterial, portal, and combined phase CT, respectively. There was no statistically significant difference in the diagnosis of active bleeding and organ injuries for any combination of two phase sets. The mean LARs for cancer incidence was 0.059%, 0.062% and 0.121% during arterial, portal and combined phase CT, respectively. CONCLUSION: Single phase CT could be a potential protocol for abdominal trauma patients. Use of single phase CT could significantly decrease the incidence of radiation-associated cancer in the future.

Virtual monoenergetic dual-layer, dual-energy CT enterography: optimization of keV settings and its added value for Crohn's disease.

OBJECTIVES: To determine the optimal keV on dual-layer, dual-energy CT enterography (dlDE-CTE) and to investigate the added value of virtual monoenergetic images (VMIs) for the diagnosis of active Crohn's disease (CD). METHODS: We collected 76 patients (including 45 CD patients) who underwent dlDE-CTE. CD was diagnosed using ileocolonoscopy. Conventional polychromatic images (PCI) were reconstructed using an iterative reconstruction algorithm at 120 kVp, and VMI at 40 keV (VMI40), 55 keV (VMI55), and 70 keV (VMI70). Contrast-to-noise ratio (CNR) was compared using Kruskal-Wallis test. Three radiologists independently reviewed PCI and subsequently combined PCI and the optimized VMI for the diagnosis of active CD using a 5-point scale. Multi-reader multi-case receiver operating characteristic analysis was performed. RESULTS: Mean ± standard deviation of CNRs for both normal (13.6±6.5, 6.1±3.2, 2.0±2.1, 1.9±1.6; P<0.001) and abnormal (9.4±7.3, 6.5±4.8, 4.9±3.1, 3.7±2.3; P<0.001) bowels were significantly greatest on VMI40, followed by VMI55, VMI70, and PCI. When VMI40 were added to PCI, overall area-under-the-curve of the three radiologists was significantly improved from 0.891 to 0.951 for diagnosing active CD (P=0.009). CONCLUSIONS: The lowest monoenergetic images (VMI40) provided the best CNR on dlDE-CTE. Furthermore, the diagnostic performance for diagnosing active CD can be significantly improved with the addition of VMI40. KEY POINTS: • CNR for both normal and abnormal bowel walls is greatest on VMI 40 . • Subjective image quality on VMI 40 is better than those on PCI. • When VMI 40 images are added to PCI, radiologists' diagnostic performance can be improved.

Risk stratification of gallbladder polyps larger than 10 mm using high-resolution ultrasonography and texture analysis.

OBJECTIVES: To assess important features for risk stratification of gallbladder (GB) polyps >10 mm using high-resolution ultrasonography (HRUS) and texture analysis. METHODS: We included 136 patients with GB polyps (>10 mm) who underwent both HRUS and cholecystectomy (non-neoplastic, n = 58; adenomatous, n = 32; and carcinoma, n = 46). Two radiologists retrospectively assessed HRUS findings and texture analysis. Multivariate analysis was performed to identify significant predictors for neoplastic polyps and carcinomas. RESULTS: Single polyp (OR, 3.680-3.856) and larger size (OR, 1.450-1.477) were independently associated with neoplastic polyps (p < 0.05). In a single or polyp >14 mm, sensitivity for differentiating neoplastic from non-neoplastic polyps was 92.3%. To differentiate carcinoma from adenoma, sessile shape (OR, 9.485-41.257), larger size (OR, 1.267-1.303), higher skewness (OR, 6.382) and lower grey-level co-occurrence matrices (GLCM) contrast (OR, 0.963) were significant predictors (p < 0.05). In a polyp >22 mm or sessile, sensitivity for differentiating carcinomas from adenomas was 93.5-95.7%. If a polyp demonstrated at least one HRUS finding and at least one texture feature, the specificity for diagnosing carcinoma was increased to 90.6-93.8%. CONCLUSION: In a GB polyp >10 mm, single and diameter >14 mm were useful for predicting neoplastic polyps. In neoplastic polyps, sessile shape, diameter >22 mm, higher skewness and lower GLCM contrast were useful for predicting carcinoma. KEY POINTS: • Risk of neoplastic polyp is low in <14 mm and multiple polyps • A sessile polyp or >22 mm has increased risk for GB carcinomas • Higher skewness and lower GLCM contrast are predictors of GB carcinoma • HRUS is useful for risk stratification of GB polyps >1 cm.

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.

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.

Intrahepatic Mass-Forming Cholangiocarcinoma: Relationship Between Computed Tomography Characteristics and Histological Subtypes.

OBJECTIVE: The aim of this study was to determine the value of multi-detector row computed tomography (MDCT) in differentiating the small-duct (SD) and large-duct (LD) types of intrahepatic mass-forming cholangiocarcinomas (IMCCs) and predicting patient prognosis. METHODS: The 4-phase MDCT image findings of 82 patients with surgically confirmed IMCCs (60 SD-type and 22 LD-type IMCCs) were compared between 2 types using univariate and multivariate analyses. Overall survival rates for 78 patients with available information were compared using the Kaplan-Meier method. RESULTS: Arterial hyperenhancement, round or lobulated contour, and lack of bile duct encasement were significant MDCT features suggesting the SD type, and lymph node enlargement was significantly associated with the LD type (all P's < 0.05). The presence of those 3 SD-type-suggestive features (MDCT-suggested SD type) demonstrated high specificity (90.9% [20/22]) in differentiating the SD type. Patients of MDCT-suggested SD type without lymph node enlargement (n = 24) demonstrated significantly better overall survival than other groups. CONCLUSIONS: Preoperative MDCT features of IMCCs can help differentiate the SD and LD types and predict patient prognosis.

Low-dose (2-mSv) computed tomography for suspected appendicitis: Applicability in an emergency department.

OBJECTIVES: To document the level of interobserver agreement and compare the diagnostic performances of emergency physicians and radiologists at interpreting low radiation CT images of acute appendicitis in adolescents and young adults. METHODS: One hundred and seven adolescents and young adult patients (aged 15 to 44years) that underwent 2-mSv low-dose CT for suspected acute appendicitis between June and December in 2013 were enrolled in this retrospective study. Three emergency physicians and three radiologists with different experiences of low-dose CT independently reviewed CT images. These six physicians rated the likelihood of acute appendicitis using a 5-point Likert scale. We calculated interobserver agreement and compared the diagnostic performances between emergency physicians and radiologists. And diagnostic confidence was also assessed using the likelihood of acute appendicitis. RESULTS: Acute appendicitis was pathologically confirmed in 42 patients (39%); the remaining 65 patients were considered not to have appendicitis. Fleiss' Kappa for reliability of agreement between emergency physicians and radiologists for the diagnosis of acute appendicitis was 0.720 (95% confidence intervals (CI), 0.685-0.726). Pooled areas under the receiver operating characteristics curve (AUC) for a diagnosis of appendicitis were 0.904 and 0.944 for emergency physicians and radiologists, respectively, and these AUC values were not significantly different (95% confidence interval, -0.087, 0.007; p=0.0855). CONCLUSION: The emergency physicians and radiologists showed good interobserver agreement and comparable diagnostic performances for appendicitis in adolescents and adults using low-dose CT images. Low-dose CT could be a useful tool for the diagnosis of appendicitis by emergency physicians.