Computed tomography diagnosis of transomental hernia,

13 N-NH 3 PET/CT in oncological disease Abstract 13N-Ammonia (13N-NH3) is widely used positron emission tomography/computed tomography (PET/CT) radiotracer for the measurement of myocardial blood perfusion; the possible role of 13N-NH3 PET or PET/CT in oncological disease is not yet clear. Aim of this review is to evaluate the diagnostic performances of 13N-NH3 PET in this field. A comprehensive computer literature search of the PubMed/MEDLINE, Scopus, and Embase databases was conducted including articles up to June 2019. Eighteen articles were finally included in the review. From the analyses of the selected studies, the following main findings could be drawn: (1) 13N-NH3 PET is useful in discriminating between gliomas and non-neoplastic brain lesions, and among gliomas between high-grade and low-grade gliomas; (2) 13N-NH3 PET have better diagnostic performance than 18F-FDG in studying gliomas; (3) a combination of 13N-NH3 PET and 18F-FDG PET may be useful to differentiate between several cerebral lesions (gliomas, cerebral lymphoma, meningioma); (4) only preliminary results about the positive impact in liver and prostate cancer.

MRI appearance change during stereotactic radiotherapy for large brain metastases and importance of treatment plan modification during treatment period Abstract Purpose We aimed to evaluate the magnetic resonance imaging (MRI) appearance changes during stereotactic radiotherapy (SRT) for large sized brain metastases, and analyze the lesions necessitating treatment plan modification. Materials and methods A total of 23 patients (27 lesions, >2 cm in tumor diameter) underwent SRT and all lesions were evaluated the appearance changes which had the necessity of the treatment plan modification. The appearance change of tumor during SRT was evaluated using gadolinium-enhanced MRI. The reasons of the modification were classified into tumor reduction, tumor enlargement, displacement, and shape change. Results Among the 27 lesions, 55.6% required the treatment plan modification. The reasons were tumor reduction in six lesions, tumor enlargement in three lesions, displacement in three lesions, and shape change in three lesions. The planning target volume (PTV) size changed up to 43.0% and the shift of center of PTV was a maximum of 1.7 mm. The pathological status (adenocarcinoma vs others) and timing of steroid administration (prior vs after SRT start) were the predictive factors of tumor changes required the modification. Conclusions As tumor changes might occur even during short period of SRT, the treatment plan evaluation and modification were important in SRT for large brain metastases.

Computed tomography findings of ceftriaxone-associated biliary pseudocholelithiasis in adults Abstract Purpose This study aimed to characterize the computed tomography (CT) findings of pseudolithiasis and investigate the outcomes and natural history in adult patients receiving CTRX therapy. Methods A total of 17 patients were diagnosed with CTRX-associated biliary pseudolithiasis on CT between April 2013 and March 2017. The medical records, characteristics, complications, treatment options, and outcomes of these patients were examined. Serial CT images and the form, density, and location of pseudolithiasis were reviewed by two radiologists. Results Of the 17 patients with CTRX-associated pseudolithiasis, seven were men and ten were women. The median patient age was 78 years (range 31–88 years). The median interval from CTRX administration to the diagnosis of pseudolithiasis was 10 days (range 4–32 days). The CT findings of pseudolithiasis included a sludge pattern (11 patients [64.7%]), stone pattern (two patients [11.8%]), and stone plus sludge pattern (four patients [23.5%]). Seven patients (41.2%) showed gall bladder enlargement along with a common bile duct (CBD) stone. Two patients with CBD stones underwent endoscopic CBD stone removal. The median time to pseudolithiasis resolution after CTRX cessation was 69 days. Conclusion The high-density sludge pattern is the most common typical CT finding of CTRX-associated pseudolithiasis in adults.

Renal pelvic and ureteral wall thickening in renal cell carcinoma: prevalence, cause, and clinical significance Abstract Purpose This study was performed to characterize renal pelvic and ureteral wall thickening (PUWT) in renal cell carcinoma (RCC) patients, including prevalence, cause, and detailed radiological findings based on contrast-enhanced CT, and to correlate these features with corresponding pathological findings. Materials and methods 152 patients pathologically diagnosed with RCC by surgery were included. Two radiologists retrospectively evaluated the presence of PUWT and the radiological characteristics based on CT. Relationships among clinical characteristics, CT findings, and PUWT were evaluated. Pathological findings of PUWT were also investigated. Results The prevalence of RCC-related PUWT was 10% (N = 15). PUWT was frequently observed in cases with advanced TNM stage. Tumor thrombus, sinus extent, and peritumoral neovascularity were significantly more frequent in cases with PUWT. PUWT was observed at the pelvis or from the pelvis to the upper ureter. Fourteen of 15 cases in which the pelvic/ureteral wall was pathologically investigated did not show any pathological abnormalities. Conclusion The prevalence of PUWT was 10% and most cases were thought to be caused by temporary vascular dilatation in the pelvis and ureter, which is a secondary condition caused by hypervascular RCC, and not a direct result of tumor invasion.

Usefulness of histologic differences and perivascular infiltration for preoperative T staging of advanced gastric cancer using computed tomography Abstract Purpose This study aimed to determine whether histologic differences and perivascular infiltration are useful for clinical T staging of advanced gastric cancer (AGC). Materials and methods This retrospective study included 160 patients with pathologically confirmed AGC who had available preoperative stomach computed tomography (CT). Using stomach CT, they were classified according to standard T stage, histologic T stage, and perivascular T stage. Accuracy of each T stage criteria was analyzed. Perivascular infiltrations for the evaluation of prognosis were correlated with time to tumor progression by log-rank test. Results There was a significant difference between the accuracies of the standard and histologic T stages (p < 0.001), whereas there was no significant difference between the standard and perivascular T stages (p = 0.07). In 121 patients who were pathologically confirmed as having T3 or T4a tumor, there was a significant difference between the standard and perivascular T stage (p < 0.001). In patients having T3 or T4a tumor, time to tumor progression of the negative perivascular infiltration subgroup was significantly longer than the positive subgroup. Conclusion Consideration of histologic differences and perivascular infiltration may be useful for clinical T staging of AGC.

Tc-99m PMT scintigraphy in the diagnosis of pediatric biliary atresia Abstract Purpose Hepatobiliary scintigraphy plays an important role in the differentiation of biliary atresia (BA) and non-BA. The usefulness of 99mTc-iminodiacetic acid (IDA) derivatives in BA diagnosis is reported in several papers. In contrast, there are no comprehensive data on differentiating BA from non-BA using 99mTc-N-pyridoxyl-5-methyl-tryptophan (PMT). Our objective was to evaluate the usefulness of 99mTc-PMT scintigraphy in the diagnosis of BA. Materials and methods 52 infants who received 99mTc-PMT scintigraphy for suspected BA were retrospectively evaluated. Preoperative cholangiograms or follow-ups were used as the gold standard for diagnosis of BA. We analyzed the utility of 99mTc-PMT scintigraphy, various clinical and investigational parameters in the diagnosis of BA. Results The final diagnoses in this group were BA (67.3%) and non-BA (32.7%). 99mTc-PMT scintigraphy, stool color change, total bilirubin, direct bilirubin, aspartate aminotransferase (AST) and γ-glutamyl transferase (γ-GTP) led to distinguishing between BA and non-BA in univariate analysis. Subsequent multivariate logistic regression analysis indicated that 99mTc-PMT scintigraphy and γ-GTP were independent predictors of BA. The diagnostic accuracy of 99mTc-PMT scintigraphy was 94.2%. Conclusions 99mTc-PMT scintigraphy is more accurate in the diagnosis of BA than other conventional examinations. In addition, false positives of 99mTc-PMT scintigraphy could be reduced by combining γ-GTP level monitoring.

Perilesional emphysema as a predictor of risk of complications from computed tomography-guided transthoracic lung biopsy Abstract Purpose This study evaluated whether or not patterns of emphysema and their qualitative and quantitative severity can predict the risk of complications with post-computed tomography (CT)-guided transthoracic lung biopsy (TTLB). Materials and methods Three hundred and ninety-seven patients who underwent CT-guided TTLB in 2010–2018 were retrospectively reviewed. The severity of emphysema and presence of perilesional emphysema were assessed visually using the Fleischner Society classification. Ninety seven of the 397 patients underwent quantitative analysis of emphysema. Complications, including pneumothorax, chest tube insertion, and hemorrhage, were assessed by post-TTLB CT and radiographic imaging. The grade of hemorrhage was categorized into three groups. Independent risk factors for pneumothorax and hemorrhage were assessed by univariate and multivariate logistic regression analyses. Results Pneumothorax occurred in 48.6% of cases and hemorrhage in 70.5%. Perilesional emphysema was significantly associated with pneumothorax (odds ratio 6.720; 95% confidence interval 3.265–13.831, p < 0.001) and hemorrhage (odds ratio 3.877; 95% confidence interval 1.796–8.367; p = 0.001). The severity of visual and quantitative emphysema was not a significant risk factor for pneumothorax or hemorrhage (p > 0.05). Perilesional emphysema was significantly associated with the grade of hemorrhage (p < 0.001). Conclusion Perilesional emphysema can estimate the risk of iatrogenic complications from CT-guided TTLB.

Machine learning-based quantitative texture analysis of conventional MRI combined with ADC maps for assessment of IDH1 mutation in high-grade gliomas Abstract Purpose To assess the performance of texture analysis of conventional magnetic resonance imaging (MRI) and apparent diffusion coefficient (ADC) maps in predicting IDH1 status in high-grade gliomas (HGG). Materials and methods A total of 142 patients with HGG were included in the study. IDH1 mutation was present in 48 of 142 HGG (33.8%). Patients were randomly divided into the training cohort (n = 96) and the validation cohort (n = 46). Texture features were extracted via regions of interest on axial T2WI FLAIR, post-contrast T1WI, and ADC maps covering the whole volume of the tumors. The training cohort was used to train the random forest classifier, and the diagnostic performance of the pre-trained model was tested on the validation cohort. Results The random forest model of conventional MRI sequences and ADC images achieved diagnostic accuracy of 82.2% and 80.4% in predicting IDH1 status in the validation cohorts, respectively. The combined model of T2WI FLAIR, post-contrast T1WI, and ADC images exhibited the highest diagnostic accuracy equating 86.94% in the validation cohort. Conclusion Texture analysis of conventional MRI sequences enhanced by ML analysis can accurately predict the IDH1 status of HGG. Adding textural analysis of ADC maps to conventional MRI results in incremental diagnostic performance.