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Objective To compare the quality of contrast enhancement and hepatic CT images acquired using bolus tracking technique at two different time points and those acquired with fixed scan delay technique using a previous bolus tracking data. Materials and methods Fifty patients who underwent 3 different hepatic CT exams (25-s fixed injection of 600 mg iodine (I)/kg or 100 mL of 370 mg I/mL nonionic contrast medium) were enrolled. The first and second exams were performed with a bolus tracking technique. The third exam was performed with a fixed scan delay technique using the first exam data. Differences in attenuation values in the abdominal organs were examined and evaluated visually on hepatic arterial phase images. Results There was no significant difference in the mean 50-HU threshold times between the first and second bolus tracking exams with intra-patient differences between them (1.3 ± 0.9 s). No significant intra-patient differences were noted in organ attenuation and visual evaluation on hepatic arterial phase images between the 3 exams. Conclusion The fixed scan delay technique using a previous bolus tracking data is feasible for hepatic CT exams to follow up hepatocellular carcinoma.

To compare primary tumor (18)F-fluorodeoxyglucose (FDG) maximum standardized uptake value (SUV(max)) and diffusion-weighted imaging (DWI) apparent diffusion coefficient (ADC) obtained in the same patients with head and neck squamous cell carcinoma (HNSCC) to clarify the prognostic significance of both indexes.The study population comprised 26 patients with HNSCC visible on both pretreatment FDG PET/CT and DWI. Correlation between SUV(max) and ADC (b values; 0 and 800 seconds/mm(2)) was analyzed by the Spearman's rank test. Disease-free survival (DFS) was calculated by the Kaplan-Meier method. Prognostic significance was assessed by the long-rank test and Cox proportional hazards analysis.SUV(max) and ADC correlated significantly and negatively (ρ = -0.566, P = 0.005). High (12.1) SUV(max) (P0.001), low (≤ 0.88) ADC (P = 0.009), high (T3-4) T stage (P = 0.030), and high (N2-3) N stage (P = 0.007) were significant in predicting poor 2-year DFS. The accuracy for predicting disease events was 81% (21/26) for SUV(max) (12.1) and 73% (19/26) for ADC(≤ 0.88) without significant difference between them (P = 0.52). Disease event hazards ratios for significant unadjusted SUV(max) (P = 0.015) and ADC (P = 0.039) remained significant when adjusted for other dichotomized clinical covariates (SUV(max); P = 0.009-0.039, ADC; P = 0.017-0.037) except SUV(max) for ADC and ADC for SUV(max) and T stage.These results suggest that pretreatment primary tumor SUV(max) and ADC correlate significantly and negatively and both may have similar potential to predict DFS or disease events of HNSCC.

We encountered two cases of epithelial-myoepithelial carcinoma (EMC), a rare low-grade malignant tumor of the parotid gland. These two EMCs showed similar imaging findings: gradual contrast enhancement on dynamic magnetic resonance imaging (MRI), intense (18)F-fluorodeoxyglucose (FDG) uptake in the solid tumor portion, and little enhancement and little FDG uptake in the hemorrhagic necrotic tumor portion. When a parotid gland tumor shows gradual MRI contrast enhancement and focally intense FDG uptake, EMC should be included in the differential diagnosis.

Aim To evaluate the usefulness of several parameters of 5 min compared to 10 min delayed contrast-enhanced CT in distinguishing adenomas from non-adenomas. Materials and methods The study population consisted of 94 patients (52 men and 42 women; mean age 62 years) with 103 adrenal lesions (75 adenomas and 28 non-adenomas). In each patient, unenhanced CT was followed by early, 5 and 10 min enhanced CT. Diagnostic parameters included delayed enhanced attenuation at 5 and 10 min, washout attenuation (WO) at 5 and 10 min, absolute percentage washout (APW) at 5 and 10 min, and relative percentage washout (RPW) at 5 and 10 min. The accuracy of each parameter for diagnosing adenomas from non-adenomas was calculated using receiver operating characteristic (ROC) analysis. Results Upon comparison between 5 and 10 min delayed contrast-enhanced CT for differentiating total adenomas or lipid-poor adenomas from non-adenomas, there was no significant difference in the area under the binomial ROC curve ( Az ) values of delayed enhanced attenuation (total adenomas versus non-adenomas, p = 0.164; lipid-poor adenomas versus non-adenomas, p = 0.178), WO (total adenomas versus non-adenomas, p = 0.216; lipid-poor adenomas versus non-adenomas, p = 0.230), APW (total adenomas versus non-adenomas, p = 0.401; lipid-poor adenomas versus non-adenomas, p = 0.870), or RPW (total adenomas versus non-adenomas, p = 0.160; lipid-poor adenomas versus non-adenomas, p = 0.780). Conclusion Five minute contrast-enhanced CT was as useful as 10 min contrast-enhanced CT for differentiation of adrenal adenomas from non-adenomas.

To evaluate the efficacy of automatic bolus tracking in multidetector row CT (MDCT) for pancreatic adenocarcinoma as compared with standard scan delay using the fixed duration contrast injection technique. Seventy-nine patients with pancreatic adenocarcinomas underwent three-phase enhanced CT with an individualized scan delay as determined by automatic bolus tracking (protocol 1) or an empiric scan delay (protocol 2). We evaluated enhancement of the aorta, portal vein, hepatic parenchyma, pancreatic parenchyma, and pancreatic adenocarcinoma during each phase. Two radiologists graded the conspicuity of pancreatic adenocarcinoma in the pancreatic parenchymal phase. The results for the different groups were statistically compared. Pancreatic parenchymal enhancement (mean ± standard deviation, 100.2 HU ± 17.6 vs. 88.5 HU ± 22.1; P

To retrospectively examine the diagnostic values of individual parameters obtained from unenhanced and 35-second and 5-minute contrast material-enhanced (enhanced) computed tomography (CT) in distinguishing adenomas, particularly lipid-poor adenomas, from nonadenomas and to determine the best diagnostic method by using these parameters.This retrospective study had institutional review board approval; the need for informed consent was waived. The study population consisted of 61 patients (20 men and 41 women; mean age, 58 years) with 68 adrenal masses (53 adenomas and 15 nonadenomas). In each patient, unenhanced CT was followed by 35-second and 5-minute enhanced CT. Adenomas were classified as 30 lipid-rich (or=10 HU) and 23 lipid-poor (10 HU) adenomas by using unenhanced attenuation. The diagnostic parameters were tumor size, unenhanced attenuation, 35-second and 5-minute enhanced attenuation, wash-in and washout attenuation, percentage enhancement washout ratio (PEW), and relative PEW (RPEW). The sensitivity, specificity, and accuracy for diagnosing adenomas were calculated by using a threshold level of each parameter determined by the least sum of false-positive and false-negative cases and a combination of the threshold levels with 100% specificity.The best results were obtained by using a combination of the threshold levels with 100% (15 of 15) specificity (presence of at least one of the following criteria for diagnosing adenomas: unenhanced attenuation ofor=19 HU, 5-minute attenuation ofor=50 HU, PEW ofor=45%, and RPEW ofor=31%). Sensitivity was 94% (50 of 53) or 87% (20 of 23) and accuracy was 96% (65 of 68) or 92% (35 of 38) for diagnosing total adrenal adenomas or lipid-poor adenomas, respectively.Combining the diagnostic parameters of the CT protocol can yield diagnostic results comparable to those with previously reported longer dynamic enhanced CT protocols.

We encountered a 49-year-old, multiparous female with a very rare isolated retroperitoneal uterine leiomyoma measuring 72 x 43 mm in diameter occurring 5 years after hysterectomy for fibroids. The case was preliminarily diagnosed as right ovarian cancer or fibroma. An edematous, isolated solid tumor in the right retroperitoneal cavity was surgically resected. Pathological findings demonstrated uterine leiomyoma.

The aim of this study was to compare the efficacy of two contrast materials with moderate and high iodine concentrations for the depiction of pancreatic adenocarcinoma. A series of 107 patients with histologically proven pancreatic adenocarcinoma underwent helical computed tomography. A fixed dose of 100 ml of iopamidol 300 (mg I/ml) was administered to 50 patients (group A) and iopamidol 370 (mg I/ml) to 57 patients (group B) at the same injection rate (3 ml/s). Unenhanced helical scans and contrast-enhanced scans for three phases (30, 70, and 300 s after starting the infusion of contrast material) were obtained. We evaluated enhancement of the aorta, portal vein, hepatic parenchyma, pancreatic parenchyma, and pancreatic adenocarcinoma during each phase. During all phases, both aortic and pancreatic enhancement were significantly greater in group B than in group A (P < 0.01). Enhancement of the portal vein and hepatic parenchyma was significantly greater at 70 and 300 s in group B than in group A (both P < 0.01). Tumor-to-pancreas contrast was significantly greater in group B than in group A at both 30 s (P < 0.01) and 70 s (P < 0.05). Administration of contrast material with a high iodine concentration is more effective for depicting pancreatic adenocarcinomas.

Intestinal malrotation is a rare anomaly of rotation and fixation of the midgut. Left-sided appendicitis occurs in association with two types of congenital anomalies, situs inversus and intestinal malrotation. We describe a rare case of left-sided acute appendicitis with intestinal malrotation in a 14-year-old boy, in which computed tomography (CT) was useful for a preoperative diagnosis.

We encountered a 9-year-old Japanese girl with Alagille syndrome. Her scintigraphic examinations of the liver were performed at the ages of 16 months and 9 years. 99mTc-PMT, a hepatobiliary imaging agent, was distributed homogeneously in the liver at the younger age, but unevenly produced an area of focally increased uptake in the medial segment of the liver surrounded by peripheral atrophy at the older age. 99mTc-GSA, a hepatoreceptor binding agent, was highly accumulated in the area, corresponding to the focally increased uptake of 99mTc-PMT. These imaging findings suggest that the pathophysiological and morphological changes of the liver occurred in our patient during the clinical course.

Paragonimiasis is an important re-emerging parasitosis in Japan. Although the lungs and pleural cavity are the principal sites affected with the parasite, ectopic infection can occur in unexpected sites such as skin and brain. This case report describes a patient with active hepatic capsulitis due to Paragonimus westermani infection. The patient was successfully treated with praziquantel at the dose of 75 mg/kg/day for 3 days.