The development and validation of a predictive model for recurrence in rectal cancer based on radiological and clinicopathological data.

OBJECTIVE: To develop a prediction model for recurrence by incorporating radiological and clinicopathological prognostic factors in rectal cancer patients. METHODS: All radiologic and clinicopathologic data of 489 patients with rectal cancer, retrospectively collected from a single institution between 2009 and 2013, were used to develop a predictive model for recurrence using the Cox regression. The model performance was validated on an independent cohort between 2015 and 2017 (N = 168). RESULTS: Out of 489 derivative patients, 103 showed recurrence after surgery. The prediction model was constructed with the following four significant predictors: distance from anal verge, MR-based extramural venous invasion, pathologic nodal stage, and perineural invasion (HR: 1.69, 2.09, 2.59, 2.29, respectively). Each factor was assigned a risk score corresponding to HR. The derivation and validation cohort were classified by sum of risk scores into 3 groups: low, intermediate, and high risk. Each of these groups showed significantly different recurrence rates (derivation cohort: 13.4%, 35.3%, 61.5 %; validation cohort: 6.2%, 23.7%, 64.7%). Our new model showed better performance in risk stratification, compared to recurrence rates of tumor node metastasis (TNM) staging in the validation cohort (stage I: 3.6%, II: 12%, III: 30.2%). The area under the receiver operating characteristic curve of the new prediction model was higher than TNM staging at 3-year recurrence in the validation cohort (0.853 vs. 0.731; p = .009). CONCLUSIONS: The new risk prediction model was strongly correlated with a recurrence rate after rectal cancer surgery and excellent for selection of high-risk group, who needs more active surveillance. KEY POINTS: • Multivariate analysis revealed four significant risk factors to be MR-based extramural venous invasion, perineural invasion, nodal metastasis, and the short distance from anal verge among the radiologic and clinicopathologic data. • Our new recurrence prediction model including radiologic data as well as clinicopathologic data showed high predictive performance of disease recurrence. • This model can be used as a comprehensive approach to evaluate individual prognosis and helpful for the selection of highly recurrent group who needs more active surveillance.

Histogram Analysis of Perfusion Parameters from Dynamic Contrast-Enhanced MR Imaging with Tumor Characteristics and Therapeutic Response in Locally Advanced Rectal Cancer.

PURPOSE: To explore the role of histogram analysis of perfusion parameters from dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) based on entire tumor volume in discriminating tumor characteristics and predicting therapeutic response in rectal cancer. MATERIALS AND METHODS: Thirty-seven DCE-MRIs of locally advanced rectal cancer patients who received chemoradiation therapy (CRT) before surgery were analyzed by pharmacokinetic model for quantification and histogram analysis of perfusion parameters. The results were correlated with tumor characteristics including EGFR expression, KRAS mutation, and CRT response based on the pathologic tumor regression grade (TRG). RESULTS: The area under the contrast agent concentration-time curve (AUC) skewness was significantly lower in patients with node metastasis. The vp histogram parameters were significantly higher in group with perineural invasion (PNI). The receiver operating characteristics (ROC) curve analyses showed that mode vp revealed the best diagnostic performance of PNI. The values of Ktrans and kep were significantly higher in the group with KRAS mutation. ROC curve analyses showed that mean and mode Ktrans demonstrated excellent diagnostic performance of KRAS mutation. DCE-MRI parameters did not demonstrate statistical significance in correlating with TRG. CONCLUSION: These preliminary results suggest that a larger proportion of higher AUC skewness was present in LN metastasis group and a higher vp histogram value was present in rectal cancer with PNI. In addition, Ktrans and kep histogram parameters showed difference according to the KRAS mutation, demonstrating the utility of the histogram of perfusion parameters derived from DCE-MRI as potential imaging biomarkers of tumor characteristics and genetic features.

Differentiation of acute cholecystitis from chronic cholecystitis: Determination of useful multidetector computed tomography findings.

The purpose of this study was to determine the diagnostic value of multidetector computed tomography (MDCT) imaging findings, to identify the most predictive findings, and to assess diagnostic performance in the diagnosis and differentiation of acute cholecystitis from chronic cholecystitis.In this retrospective study, we enrolled 382 consecutive patients with pathologically proven acute or chronic cholecystitis who underwent computed tomography (CT) within 1 month before surgery. The CT findings were compared and logistic regression analysis was used to identify significant CT findings in predicting acute cholecystitis. Diagnostic performance of each CT finding and of combined findings was also assessed.Statistically significant CT findings distinguishing acute cholecystitis from chronic cholecystitis were increased gallbladder dimension (85.5% vs 50.6%, P < .001), increased wall enhancement (61.8% vs 78.9%, P = .001), increased wall thickness (67.9% vs 31.1%, P < .001), mural striation (64.9% vs 28.3%, P < .001), pericholecystic haziness or fluid (66.4% vs 21.2%, P < .001), increased adjacent hepatic enhancement (80.0% vs 32.4%, P < .001), focal wall defect (9.2% vs 0, P < .001), and pericholecystic abscess (10.7% vs 0, P < .001). Subsequent multivariate logistic regression analysis revealed that increased adjacent hepatic enhancement [P = .006, odds ratio (OR) = 3.82], increased gallbladder dimension (P = .027, OR = 3.12), increased wall thickening or mural striation (P = .019, OR = 2.89), and pericholecystic haziness or fluid (P = .032, OR = 2.61) were significant predictors of acute cholecystitis. When 2 of these 4 CT findings were observed together, the sensitivity, specificity, and accuracy for the detection of acute cholecystitis were 83.2%, 65.7%, and 71.7%, respectively. When 3 of these 4 CT findings were observed together, the sensitivity, specificity, and accuracy were 56.5%, 84.5%, and 74.9%, respectively. When none of these 4 CT findings were observed, the negative predictive value was 96.4%.Increased adjacent hepatic enhancement, increased gallbladder dimension, increased wall thickening or mural striation, and pericholecystic fat haziness or fluid were the most discriminative MDCT findings for the diagnosis and differentiation of acute cholecystitis from chronic cholecystitis.

Performance of Gadoxetic Acid-Enhanced Liver Magnetic Resonance Imaging for Predicting Patient Eligibility for Liver Transplantation Based on the Milan Criteria.

PURPOSE: This study aimed to evaluate the accuracy of gadoxetic acid-enhanced magnetic resonance imaging (Gd-EOB-MRI) in predicting eligibility for liver transplantation in patients with hepatocellular carcinoma (HCC) based on Milan criteria (MC). MATERIALS AND METHODS: We reviewed Gd-EOB-MRI of 44 patients who underwent liver transplantation for HCC with cirrhosis for the presence/size of HCCs, vascular invasion, and transplant eligibility based on MC. Hepatocellular carcinoma was diagnosed based on conventional radiological hallmarks (arterial enhancement and washout) or the modified criteria. RESULTS: Among 44 patients, 16 was beyond MC. Sensitivity, specificity, and accuracy of conventional radiological hallmark and the modified criteria for predicting eligibility by MC were 31.3%, 96.3%, and 72.7%, and 68.8%, 96.3%, and 86.4%, respectively. CONCLUSIONS: Gd-EOB-MRI showed high specificity but poor sensitivity for assessing transplant eligibility based on MC when adopting the conventional radiological hallmarks of HCC. Our modified criteria showed significantly better sensitivity and accuracy than the conventional radiological hallmarks.

Risk factors of biliary intervention by imaging after living donor liver transplantation.

AIM: To determine the risk factors of biliary intervention using magnetic resonance cholangiopancreatography (MRCP) after living donor liver transplantation (LDLT). METHODS: We retrospectively enrolled 196 patients who underwent right lobe LDLT between 2006 and 2010 at a single liver transplantation center. Direct duct-to-duct biliary anastomosis was performed in all 196 patients. MRCP images routinely taken 1 mo after LDLT were analyzed to identify risk factors for biliary intervention during follow-up, such as retrograde cholangiopancreatography or percutaneous transhepatic biliary drainage. Two experienced radiologists evaluated the MRCP findings, including the anastomosis site angle on three-dimensional images, the length of the filling defect on maximum intensity projection, bile duct dilatation, biliary stricture, and leakage. RESULTS: Eighty-nine patients underwent biliary intervention during follow-up. The anastomosis site angle [hazard ratio (HR) = 0.48; 95% confidence interval (CI), 0.30-0.75, P < 0.001], a filling defect in the anastomosis site (HR = 2.18, 95%CI: 1.41-3.38, P = 0.001), and biliary leakage (HR = 2.52, 95%CI: 1.02-6.20, P = 0.048) on MRCP were identified in the multivariate analysis as significant risk factors for biliary intervention during follow-up. Moreover, a narrower anastomosis site angle (i.e., below the median angle of 113.3°) was associated with earlier biliary intervention (38.5 ± 4.2 mo vs 62. 1 ± 4.1 mo, P < 0.001). Kaplan-Meier analysis comparing biliary intervention-free survival according to the anastomosis site angle revealed that lower survival was associated with a narrower anastomosis site angle (36.3% vs 62.0%, P < 0.001). CONCLUSION: The biliary anastomosis site angle in MRCP after LDLT may be associated with the need for biliary intervention.

Optimal cut-off value of perfusion parameters for diagnosing prostate cancer and for assessing aggressiveness associated with Gleason score.

To determine cut-off value of dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) parameters for differentiation of prostate malignant from benign and cancer with high-grade Gleason score (GS) (GS>7) from low-grade GS (GS≤7), 35 patients (24 malignant and 11 benign) who underwent DCE-MRI were included. Difference between malignant and benign was statistically significant for all magnetic resonance parameters except Ve. The cut-off values were K(trans)=0.184min(-1), Kep=0.695min(-1), iAUC=4.219mmol/l/min, and ADC=1340.5mm(2)/s. A significant difference in mean values of K(trans) and Kep between cancer with high-grade GS and low-grade GS was also observed. K(trans) and Kep showed a significant correlation with GS.

Computed tomography and magnetic resonance imaging evaluation of lymph node metastasis in early colorectal cancer.

AIM: To assess the role of computed tomography (CT) and magnetic resonance imaging (MRI) and establish imaging criteria of lymph node metastasis in early colorectal cancer. METHODS: One hundred and sixty patients with early colorectal cancer were evaluated for tumor location, clinical history of polypectomy, depth of tumor invasion, and lymph node metastasis. Two radiologists assessed preoperative CT and/or MRI for the primary tumor site detectability, the presence or absence of regional lymph node, and the size of the largest lymph node. Demographic, imaging, and pathologic findings were compared between the two groups of patients based on pathologic lymph node metastasis and optimal size criterion was obtained. RESULTS: The locations of tumor were ascending, transverse, descending, sigmoid colon, and rectum. One hundred and sixty early colorectal cancers were classified into 3 groups based on the pathological depth of tumor invasion; mucosa, submucosa, and depth unavailable. A total of 20 (12.5%) cancers with submucosal invasion showed lymph node metastasis. Lymph nodes were detected on CT or MRI in 53 patients. The detection rate and size of lymph nodes were significantly higher (P = 0.000, P = 0.044, respectively) in patients with pathologic nodal metastasis than in patients without nodal metastasis. Receiver operating curve analysis showed that a cut-off value of 4.1 mm is optimal with a sensitivity of 78.6% and specificity of 75%. CONCLUSION: The short diameter size criterion of ≥ 4.1 mm for metastatic lymph nodes was optimal for nodal staging in early colorectal cancer.

Correlation of dynamic contrast-enhanced MRI perfusion parameters with angiogenesis and biologic aggressiveness of rectal cancer: Preliminary results.

PURPOSE: To investigate whether quantitative parameters derived from dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) are correlated with angiogenesis and biologic aggressiveness of rectal cancer. MATERIALS AND METHODS: A total of 46 patients with rectal cancer underwent DCE-MRI. Using a two-compartmental model, quantitative parameters (K(trans) , kep , ve , and iAUC) were calculated from the whole-transverse region of interest (ROI) and high K(trans) area ROI of entire tumors. Histological specimens were analyzed for tumor size; T/N stage; lymphatic, vascular, perineural invasion; expression of epidermal growth factor receptor (EGFR); and KRAS gene mutations. Tumor angiogenesis was evaluated based on the microvessel density (MVD) and the expression level of the vascular endothelial growth factor. Correlations of the DCE-MRI parameters with histological markers and angiogenesis were determined using Student's t-test and analysis of variance (ANOVA). RESULTS: The mean kep from high K(trans) area ROIs showed a significantly positive correlation with MVD (P = 0.030, r = 0.514, R(2) = 0.264). The mean kep from the whole-transverse ROIs showed a significant inverse correlation with T stage (T1 vs. T2-4, P = 0.021). EGFR-positive cancer displayed higher mean K(trans) (P = 0.045) and kep (P = 0.038) than EGFR-negative cancer in whole-transverse ROIs. CONCLUSION: These preliminary results suggest that the determination of kep of high K(trans) area permits the noninvasive estimation of tumor angiogenesis in rectal cancer and that DCE-MRI parameters can be used as imaging biomarkers to predict the biologic aggressiveness of the tumor and patient prognosis.

The association between ectopic fat in the pancreas and subclinical atherosclerosis in type 2 diabetes.

AIMS: Evidence that pancreatic fat accumulation has a role in obesity, metabolic syndrome and type 2 diabetes mellitus (DM) is emerging. However, data on the influence of pancreatic steatosis on subclinical atherosclerosis are lacking. METHODS: We examined 198 patients with type 2 DM. Pancreatic computed tomography (CT) attenuations were assessed using CT imaging. Obesity was defined as BMI ≥ 25 kg/m(2) according to the Asian-specific BMI cut-offs. We defined pancreatic steatosis as pancreatic attenuations below median levels. RESULTS: The pancreatic attenuations was significantly correlated with age (r=-0.302, p<0.001), visceral fat area (r=-0.194, p=0.006) and vascular stiffness (r=-0.242, p=0.001). In the non-obese group (BMI<25 kg/m(2)), pancreatic steatosis was associated with a higher prevalence of carotid artery plaque and vascular stiffness. In the non-obese group, patients with pancreatic steatosis, compared with those without, had an odds ratio (OR) of 3.1 (95% CI 1.2-8.1) for carotid atherosclerosis, after adjusting for age, gender and BMI. However, significant associations between pancreatic steatosis and atherosclerosis were not found in the obese group. CONCLUSION: Ectopic fat in the pancreas is strongly associated with carotid atherosclerosis in non-obese subjects with type 2 DM. This finding highlights the importance of pancreatic fat deposits related to a higher risk of cardiovascular disease, especially in non-obese subjects.

Intra- and interobserver reliability of gray scale/dynamic range evaluation of ultrasonography using a standardized phantom.

PURPOSE: To evaluate intra- and interobserver reliability of the gray scale/dynamic range of the phantom image evaluation of ultrasonography using a standardized phantom, and to assess the effect of interactive education on the reliability. METHODS: Three radiologists (a resident, and two board-certified radiologists with 2 and 7 years of experience in evaluating ultrasound phantom images) performed the gray scale/dynamic range test for an ultrasound machine using a standardized phantom. They scored the number of visible cylindrical structures of varying degrees of brightness and made a 'pass or fail' decision. First, they scored 49 phantom images twice from a 2010 survey with limited knowledge of phantom images. After this, the radiologists underwent two hours of interactive education for the phantom images and scored another 91 phantom images from a 2011 survey twice. Intra- and interobserver reliability before and after the interactive education session were analyzed using K analyses. RESULTS: Before education, the K-value for intraobserver reliability for the radiologist with 7 years of experience, 2 years of experience, and the resident was 0.386, 0.469, and 0.465, respectively. After education, the K-values were improved (0.823, 0.611, and 0.711, respectively). For interobserver reliability, the K-value was also better after the education for the 3 participants (0.067, 0.002, and 0.547 before education; 0.635, 0.667, and 0.616 after education, respectively). CONCLUSION: The intra- and interobserver reliability of the gray scale/dynamic range was fair to substantial. Interactive education can improve reliability. For more reliable results, double- checking of phantom images by multiple reviewers is recommended.

Comparison of RECIST, mRECIST, and choi criteria for early response evaluation of hepatocellular carcinoma after transarterial chemoembolization using drug-eluting beads.

OBJECTIVE: To determine appropriate imaging criteria for early response evaluation in patients with hepatocellular carcinoma treated with transarterial chemoembolization (TACE) using drug-eluting beads. METHODS: Seventy-six patients who underwent TACE with drug-eluting beads as a first-line treatment were included. Responses at 1 month after treatment were evaluated by comparing contrast-enhanced computed tomography or magnetic resonance imaging performed before TACE. Evaluations were performed according to Response Evaluation Criteria in Solid Tumors (RECIST), modified RECIST (mRECIST), and Choi criteria. Correlation with progression-free survival (PFS) was compared using the Kaplan-Meier method and log-rank test. RESULTS: Modified RECIST yielded a significant difference in PFS across the different response categories (P < 0.01); the Choi criteria exhibited a satisfactory difference in PFS, although the number of nonresponder patients was small (n = 5 [8.6%]). CONCLUSION: Application of mRECIST criteria at the 1-month follow-up computed tomography may be a reliable early predictor of outcome response in patients with hepatocellular carcinoma treated with TACE using drug-eluting beads.

Temporal evolution of multidetector CT findings after endoscopic submucosal dissection in patients with early gastric cancer: correlation with endoscopy.

OBJECTIVE: To assess changes over time in imaging findings retrospectively by multidetector CT (MDCT) with two-dimensional (2D) multiplanar reconstruction and three-dimensional (3D) CT gastrography (CTG), after endoscopic submucosal dissection (ESD) in patients with early gastric cancer (EGC), and to correlate 3D CT images with endoscopic appearance. MATERIALS AND METHODS: In this retrospective study, a total of 84 patients underwent ESD and were followed up with MDCT. Fifteen patients underwent CT twice, and 3 patients underwent CT 3 times. A total of 105 CTs were included in this study and 43 CTs contained 3D CTGs. Two radiologists in consensus interpreted CT images for lesion detectability, presence and characteristics of ulcer, focal wall thickening, perigastric fat infiltration, and overlying enhancing layer in 2D images. The presence of ulcer or subtle mucosal nodularity, ulcer mound, and fold convergence were analysed in 3D CT images. We also assessed the time interval between ESD and CT and analysed the temporal evolution of CT findings. The sensitivity, specificity, and overall accuracy of 3D CTG were assessed regarding endoscopic features as the gold standard. RESULTS: The mean interval between ESD and follow up CT was 76.9 days (median, 62; range, 2-223). No tumour recurrence in any lesion was found on follow-up endoscopic biopsy and also lymph node or distant metastasis was not observed on CT exams in the follow-up period. The lesion detectability in a total of 105 post-ESD 2D CT images was 42.0% (44/105), and 93.2% (41/44) of the detected lesions were visualizable 2 months after ESD. Focal wall thickening was observed during the entire follow-up period in all patients. Perigastric fat infiltration was observed in 4 lesions within 1 week of ESD. Overlying enhancing layer appeared in 27 lesions without temporal evolution. On a total of 43 post-ESD 3D CTG, lesion detectability was 76.7% (33/43), and lesions could be visualized for a longer period than by 2D CT images (223 days versus 99 days). Three-dimensional imaging features revealed ulcer, ulcer mound, and fold convergence. Ulcer mounds disappeared first (median, 12.5 days; range, 2-14 days after ESD), ulcers appeared up to 4 months after ESD (median, 14 days; range, 2-174 days after ESD) and fold convergence continued to the end of the study (median, 74 days; range, 2-223 days after ESD). We found that sensitivity, specificity, and overall accuracy of 3D CTG were 70.0%, 92.9%, 83.3% for ulcer, 28.6%, 100%, 71.4% for ulcer mound, and 71.4%, 100%, 75% for fold convergence regarding endoscopy, respectively. CONCLUSION: On follow-up 2D or 3D CT images after ESD, early findings were of perigastric fat infiltration, ulcer, and surrounding oedema. Focal wall thickening and fold convergence continued to be observed late in the study. The overlying enhancing layer did not show temporal evolution.

MR imaging findings of extraovarian endocervical mucinous borderline tumors arising from pelvic endometriosis.

We report MR imaging findings of a rare case of endocervical mucinous borderline tumor (MBT) involving the cul-de-sac and left fallopian tube arising from extensive pelvic endometriosis with pathologic correlation in a 35-year-old woman presented with vague pelvic pain. Endocervical MBT is a type of endometriosis-associated carcinoma. Imaging findings of endocervical MBT are unilocular or oligolocular cystic lesions with enhancing mural nodules, which are different from those of the more common intestinal type MBT.

Postoperative ileo-ileal intussusception following surgical resection of patent omphalomesenteric duct.

A female neonate with patent omphalomesenteric duct was treated by ductal excision. Six days following surgery, she developed vomiting and abdominal distension. On plain radiographs, distended bowel loops with multiple, air-fluid levels consistent with an intestinal obstruction were evident. Sonography demonstrated an ileo-ileal intussusception. At surgery, a 3-cm, ileo-ileal intussusception was noted proximal to the previous Lembert suture site and was manually reduced. Awareness of the possibility of small-bowel intussusception following surgery was critical to ensuring prompt and successful treatment of this infant.

Gliomatosis peritonei of the scrotal sac associated with an immature gastric teratoma.

A male infant presented with bilateral scrotal masses 7 months after removal of an immature gastric teratoma. After surgical excision, histology showed gliomatosis peritonei. We report an unusual presentation of gliomatosis peritonei arising from a rare lesion of immature gastric teratoma.

Kikuchi's disease in children: clinical manifestations and imaging features.

Previously published studies on Kikuchi disease (KD) have frequently addressed the computed tomography (CT) findings in the adult population, however, only a few studies have been reported for the pediatric age group. The purpose of this study is to analyze the clinical characteristics and imaging features of KD in children. Fifteen children (2-14 yr) who had a neck CT and pathology diagnosis of KD were included in this study. Clinical features, including the duration of lymphadenopathy and fever, prognosis, and laboratory values, were evaluated. We analyzed the sites, size, and lymph node pattern as seen on their CT scans. The median duration of fever was 10 days. Fourteen patients experienced improvement in their condition, although four of these patients experienced recurrent episodes of KD. All patients had affected cervical nodes at level V. Perinodal infiltrates were observed in the affected cervical nodes in 14 cases (93%), and non-enhancing necrosis was also noted within the affected cervical nodes in 10 cases (63%). In conclusion, the combination of imaging findings in conjunction with clinical findings of KD may help to determine whether or not to perform pathology analysis and follow-up studies.