Liver fluke disease is a chronic parasitic inflammatory disease of the bile ducts. Infection occurs through ingestion of fluke-infested, fresh-water raw fish. The most well-known species that cause human infection are Clonorchis sinensis, Opisthorchis viverrini and Opisthorchis felineus. Adult flukes settle in the small intrahepatic bile ducts and then they live there for 20-30 years. The long-lived flukes cause long-lasting chronic inflammation of the bile ducts and this produces epithelial hyperplasia, periductal fibrosis and bile duct dilatation. The vast majority of patients are asymptomatic, but the patients with heavy infection suffer from lassitude and nonspecific abdominal complaints. The complications are stone formation, recurrent pyogenic cholangitis and cholangiocarcinoma. Approximately 35 million people are infected with liver flukes throughout the world and the exceptionally high incidence of cholangiocarcinoma in some endemic areas is closely related with a high prevalence of liver fluke infection. Considering the impact of this food-borne malady on public health and the severe possible clinical consequences, liver fluke infection should not be forgotten or neglected.

Objective: We wanted to differentiate between transient ischemic attack (TIA) and minor stroke using fractional anisotropy and three-dimensional (3D) fiber tractography. Materials and Methods: The clinical data, conventional magnetic resonance imaging (MRI), diffusion weighted imaging (DWI) and diffusion tensor imaging (DTI) were obtained for 45 TIA patients and 33 minor stroke patients. The fractional anisotrophy ratio (rFA) between the lesion and the mirrored corresponding contralateral normal tissue was calculated and analyzed. The spatial relationship between the lesion and the corticospinal tract (CST) was analyzed and the lesion sizes in the minor stroke patients and TIA patients were compared. Results: Twenty-two of the 45 TIA patients (49%) revealed focal abnormalities following DWI. The rFA was significantly lower (p < 0.05) in the stroke patients (0.71 ${\pm}$ 0.29) compared to that of the TIA patients (1.05 ${\pm}$ 0.37). The CST was involved in almost all stroke lesions, but it was not involved in 68% of the TIA lesions. The TIA patients had significantly lower CST injury scores (3.25 ${\pm}$ 1.75) than did the stroke patients (8.80 ${\pm}$ 2.39) (p = 0.004). Conclusion: Our data indicate that TIA and minor stroke can be identified by analyzing the rFA and the degree of CST involvement, and this may also allow more accurate prediction of a patient's long-term recovery or disability.

Objective: The aim of this study was to use fractal dimension (FD) analysis on multidetector CT (MDCT) images for quantifying the morphological changes of the pulmonary artery tree in patients with pulmonary hypertension (PH). Materials and Methods: Fourteen patients with PH and 17 patients without PH as controls were studied. All of the patients underwent contrast-enhanced helical CT and transthoracic echocardiography. The pulmonary artery trees were generated using post-processing software, and the FD and projected image area of the pulmonary artery trees were determined with ImageJ software in a personal computer. The FD, the projected image area and the pulmonary artery pressure (PAP) were statistically evaluated in the two groups. Results: The FD, the projected image area and the PAP of the patients with PH were higher than those values of the patients without PH (p < 0.05, t-test). There was a high correlation of FD with the PAP (r = 0.82, p < 0.05, partial correlation analysis). There was a moderate correlation of FD with the projected image area (r = 0.49, p < 0.05, partial correlation analysis). There was a correlation of the PAP with the projected image area (r = 0.65, p < 0.05, Pearson correlation analysis). Conclusion: The FD of the pulmonary arteries in the PH patients was significantly higher than that of the controls. There is a high correlation of FD with the PAP.

Objective: To evaluate the usefulness of an automated system for quantification and discrimination of usual interstitial pneumonia (UIP) and nonspecific interstitial pneumonia (NSIP). Materials and Methods: An automated system to quantify six regional high-resolution CT (HRCT) patterns: normal, NL: ground-glass opacity, GGO: reticular opacity, RO: honeycombing, HC: emphysema, EMPH: and consolidation, CONS, was developed using texture and shape features. Fifty-four patients with pathologically proven UIP (n = 26) and pathologically proven NSIP (n = 28) were included as part of this study. Inter-observer agreement in measuring the extent of each HRCT pattern between the system and two thoracic radiologists were assessed in 26 randomly selected subsets using an interclass correlation coefficient (ICC). A linear regression analysis was used to assess the contribution of each disease pattern to the pulmonary function test parameters. The discriminating capacity of the system between UIP and NSIP was evaluated using a binomial logistic regression. Results: The overall ICC showed acceptable agreement among the system and the two radiologists (r = 0.895 for the abnormal lung volume fraction, 0.706 for the fibrosis fraction, 0.895 for NL, 0.625 for GGO, 0.626 for RO, 0.893 for HC, 0.800 for EMPH, and 0.430 for CONS). The volumes of NL, GGO, RO, and EMPH contribute to forced expiratory volume during one second ($FEV_1$) (r = 0.72, $\beta$ values, 0.84, 0.34, 0.34 and 0.24, respectively) and forced vital capacity (FVC) (r = 0.76, $\beta$ values, 0.82, 0.28, 0.21 and 0.34, respectively). For diffusing capacity ($DL_{CO}$), the volumes of NL and HC were independent contributors in opposite directions (r = 0.65, $\beta$ values, 0.64, -0.21, respectively). The automated system can help discriminate between UIP and NSIP with an accuracy of 82%. Conclusion: The automated quantification system of regional HRCT patterns can be useful in the assessment of disease severity and may provide reliable agreement with the radiologists' results. In addition, this system may be useful in differentiating between UIP and NSIP.

Objective: We wanted to evaluate the image quality, diagnostic accuracy and radiation exposure of 64-slice dual-source CT (DSCT) coronary angiography according to the heart rate in symptomatic patients during daily clinical practice. Materials and Methods: We performed a retrospective search for the DSCT coronary angiography reports of 729 consecutive symptomatic patients. For the 131 patients who underwent invasive coronary angiography, the image quality, the diagnostic performance (sensitivity, specificity, positive predictive value [PPV] and negative predictive value [NPV] for detecting significant stenosis ${\geq}$ 50% diameter) and the radiation exposure were evaluated. These values were compared between the groups with differing heart rates (HR): mean HR < 65 or ${\geq}$ 65 and HR variability (HRV) < 15 or ${\geq}$ 15. Results: Among the 729 patients, the CT reports showed no stenosis or insignificant coronary artery stenosis in 72%, significant stenosis in 26% and non-diagnostic in 2%. For the 131 patients who underwent invasive coronary angiography, 95% of the patients and 97% of the segments were evaluable, and the overall per-patient/per-segment sensitivity, the perpatient/per-segment specificity, the per-patient/per-segment PPV and the per-patient/per-segment NPV were 100%/90%, 71%/98%, 95%/88% and 100%/97%, respectively. The image quality was better in the HR < 65 group than in the HR ${\geq}$ 65 group (p = 0.001), but there was no difference in diagnostic performance between the two groups. The mean effective radiation doses were lower in the HR < 65 or HRV < 15 group (p < 0.0001): 5.5 versus 6.7 mSv for the mean HR groups and 5.3 versus 9.3 mSv for the HRV groups. Conclusion: Dual-source CT coronary angiography is a highly accurate modality in the clinical setting. Better image quality and a significant radiation reduction are being rendered in the lower HR group.

Objective: The purpose of this study is to determine the effects of propranolol on the left ventricular (LV) volume during CT coronary angiography. Materials and Methods: The LV volume of 252 normal Chinese subjects (126 subjects with propranolol medication and 126 age- and gender-matched Chinese subjects without medication) was estimated using 64 slices multi-detector CT (MDCT). The heart rate difference was analyzed by the logistic linear regression model with variables that included gender, age, body height, body weight, systolic blood pressure (SBP), diastolic blood pressure (DBP) and the dosage of propranolol. The following global LV functional parameters were calculated: the real-end diastolic volume (EDV), the real-end systolic volume (ESV) and the real-ejection fraction (EF). Results: The female subjects had a greater decrease of heart rate after taking propranolol. The difference of heart rate was negatively correlated with the dosage of propranolol. The real-EDV, the real-ESV and the real-EF ranged from 48.1 to 109 mL/$m^2$, 6.1 to 57.1 mL/$m^2$ and 41% to 88%, respectively. There was no significant difference in the SBP and DBP between the groups without and with propranolol medication (123 ${\pm}$ 17 and 80 ${\pm}$ 10 mmHg; 120 ${\pm}$ 14 and 80 ${\pm}$ 11 mmHg, respectively). The real-EDV showed no significant difference between these two groups, but the real-ESV and real- EF showed significant differences between these two groups (69.4 ${\pm}$ 9.3 and 70.6 ${\pm}$ 8.9 mL/$m^2$ 23.5 ${\pm}$ 5.7 and 25.6 ${\pm}$ 3.7 mL/$m^2$, 66.5 ${\pm}$ 5.1% and 63.5 ${\pm}$ 4.6%, respectively). Conclusion: The difference of heart rate is significantly influenced by gender and the dosage of propranolol. Propranolol will also increase the ESV, which contributes to a decreased EF, while the SBP, DBP and EDV are not statistically changed.

Objective: We wanted to describe the three-dimensional (3D) anatomic variations of the femoral vein (FV) and popliteal vein (PV) in relation to the accompanying artery using CT venography. Materials and Methods: We performed a retrospective review of 445 bilateral (890 limbs) lower limb CT venograms. After the 3D relationship between the FV and PV and accompanying artery was analyzed, the presence or absence of variation was determined and the observed variations were classified. In each patient, the extent and location of the variations and the location of the adductor hiatus were recorded to investigate the regional frequency of the variations. Results: There were four distinct categories of variations: agenesis (3 limbs, 0.3%), multiplication (isolated in the FV: 190 limbs, 21%; isolated in the PV: 14 limbs, 2%; and in both the FV and PV: 51 limbs, 6%), anatomical course variation (75 limbs, 8%) and high union of the tibial veins (737 limbs, 83%). The course variations included medial malposition (60 limbs, 7%), anterior rotation (11 limbs, 1%) and posterior rotation (4 limbs, 0.4%). Mapping the individual variations revealed regional differences in the pattern and frequency of the variations. Conclusion: CT venography helps to confirm a high incidence of variations in the lower limb venous anatomy and it also revealed various positional venous anomalies in relation to the respective artery.

Objective: We wanted to validate the additional merit of the thinner coronal reformation images from multidetector CT (MDCT) for making the diagnosis of hepatic cysts. Materials and Methods: For the 90 benign hepatic cysts confirmed on MRI, the transverse (5-mm thickness) and additional coronal (2-mm thickness) reformation images from MDCT were compared with each other in terms of the Hounsfield units (HUs) and the size of each hepatic cyst. Results: The attenuations (mean: 17.2 HUs, standard deviation: ${\pm}$ 14.4) on the thinner coronal images were significantly lower than those (mean: 40.7 HUs: standard deviation: ${\pm}$ 20.6) on the thicker transverse images for the small hepatic cysts (${\leq}$ 10 mm on the transverse image, p < 0.01). Twenty-three (79%) of the 29 cysts between 5 mm and 10 mm and 21 (51%) of 41 lesions up to 5 mm showed a mean HU value of 20 or less on the coronal reformation images. Conclusion: By reducing the partial volume effect, routine coronal reformation of MDCT with a thinner section thickness can provide another merit for making a confidential diagnosis of many small sub-centimeter hepatic cysts, and these small cysts are not easily characterized on the conventional transverse images.

Objective: The purpose of this study was to investigate retrospectively the clinical procedural performance of CT-guided needle biopsy for retroperitoneal lesions. Materials and Methods: CT-guided needle biopsy was performed in 74 consecutive patients (M:F = 44:30; mean age, 59.7 years) with retroperitoneal lesions between April 1998 and June 2009. The target lesion ranged from 1.5 to 12.5 cm in size. The biopsy access path ranged from 3.5 to 11.5 cm in depth. A biopsy specimen was obtained using an 18-gauge core needle under a CT or CT-fluoroscopy guidance and with the patient under local anesthesia. The histopathological diagnoses from the biopsies were obtained. The diagnostic confirmation of the subtype of lymphoma was evaluated. Results: Satisfactory biopsy samples were obtained in 73 (99%) of 74 patients and a pathological diagnosis was made in 70 (95%) of 74 patients. Sixty three lesions were malignant (45 lymphomas, nine primary tumors, nine lymph node metastases) and seven were benign. The subtype of lymphoma was specified in 43 (96%) of 45 patients who were diagnosed with lymphoma. Analysis of the value of CT-guided biopsy in this series indicated 63 true positives, zero false positive, six true negatives and five false negatives. This test had a sensitivity of 93%, a specificity of 100% and an accuracy of 93%. No major complications were seen and minor complications were noted in seven patients (five with local hematomas, two with transient pain at the puncture site). Conclusion: CT-guided needle biopsy for retroperitoneal lesions is highly practical and useful, and particularly for determining the subtypes in patients with lymphoma.

Objective: Clear depiction of the common bile duct is important when evaluating neonatal cholestasis in order to differentiate biliary atresia from other diseases. During MR cholangiopancreatography, the T2-shortening effect of gadolinium can increase the contrast-to-noise ratio (CNR) of the bile duct and enhance its depiction. The purpose of this study was to confirm, by performing a phantom study, the T2-shortening effect of gadolinium, to evaluate the effect of different gadolinium chelates with different gadolinium concentrations and different magnetic field strengths for investigating the optimal combination of these conditions, and for identifying the maximum CNR for the evaluation of the biliary system. Materials and Methods: MR imaging using a T2-weighted single-shot fast spin echo sequence and T2 relaxometry was performed with a sponge phantom in a syringe tube. Two kinds of contrast agents (Gd-DTPA and Gd-EOB-DTPA) with different gadolinium concentrations were evaluated with 1.5T and 3T scanners. The signal intensities, the CNRs and the T2 relaxation time were analyzed. Results: The signal intensities significantly decreased as the gadolinium concentrations increased (p < 0.001) with both contrast agents. These signal intensities were higher on a 3T (p < 0.001) scanner. The CNRs were higher on a 1.5T (p < 0.001) scanner and they showed no significant change with different gadolinium concentrations. The T2 relaxation time also showed a negative correlation with the gadolinium concentrations (p < 0.001) and the CNRs showed decrease more with Gd-EOB-DTPA (versus Gd-DTPA; p < 0.001) on a 3T scanner (versus 1.5T; p < 0.001). Conclusion: A T2-shortening effect of gadolinium exhibits a negative correlation with the gadolinium concentration for both the signal intensities and the T2 relaxation time. A higher CNR can be obtained with Gd-DTPA on a 1.5T MRI scanner.

Elastography is an ultrasound-based newer imaging technique that is currently being used for the evaluation of breast lesions and hepatic pathology. It is also being evaluated for characterizing lesions of the prostate, thyroid, cervix and lymph nodes. We have applied real-time sonoelastography to a variety of musculoskeletal pathologies and here we report the findings of elastography for the evaluation of various musculoskeletal pathologies. Elastography of musculoskeletal lesions is not yet being routinely used in clinical practice, but it is being extensively researched.

We report a case of thymic hyperplasia accompanied by pericardial lipomatosis and right facial hemihypertrophy in an 8-year-old boy. On imaging studies, the hyperplastic thymus had prominent curvilinear and nodular fatty areas simulating a fat-containing anterior mediastinal mass, which is an unusual finding in children. To our knowledge, this is the first report on a child with a combination of thymic hyperplasia, pericardial lipomatosis, and right facial hemihypertrophy. The radiologic findings are presented with a brief discussion.

Hepatic involvement of amyloidosis is common. Diffuse infiltration with hepatomegaly is a usual radiologic finding of hepatic amyloidosis. To our knowledge, this is the first case of amyloidosis involving the liver that presented as a mass.

We report here on the redistributed regional ventilation abnormalities after the administration of a bronchodilator and as seen on xenon-inhaled dual-energy CT in a patient with asthma. The improved ventilation seen in the right lower lobe and the decreased ventilation seen in the right middle lobe after the administration of a bronchodilator on xenon-inhaled dual-energy CT could explain a positive bronchodilator response on a pulmonary function test. These changes may reflect the heterogeneity of the airway responsiveness to a bronchodilator in patients with asthma.

Pericardial fat necrosis is an infrequent cause of acute chest pain and this can mimic acute myocardial infarction and acute pericarditis. We describe here a patient with the magnetic resonance imaging (MRI) findings of pericardial fat necrosis and this was correlated with the computed tomography (CT) findings. The MRI findings may be helpful for distinguishing pericardial fat necrosis from other causes of acute chest pain and from the fat-containing tumors in the cardiophrenic space of the anterior mediastinum.

We present two cases of individual pulmonary vein atresia without vestige of an involved pulmonary vein. On CT, we noted the absence or interruption of normal pulmonary venous structures, and the presence of abnormal vascular structures that represented collaterals for the involved lung parenchyma. On angiography, the atretic pulmonary vein was found to drain into the other ipsilateral pulmonary veins through the collaterals.