Po-Pang Tsai’s research while affiliated with China Medical University Hospital and other places

The American Journal of Gastroenterology is published by Nature Publishing Group (NPG) on behalf of the American College of Gastroenterology (ACG). Ranked the #1 clinical journal covering gastroenterology and hepatology*, The American Journal of Gastroenterology (AJG) provides practical and professional support for clinicians dealing with the gastroenterological disorders seen most often in patients. Published with practicing clinicians in mind, the journal aims to be easily accessible, organizing its content by topic, both online and in print. www.amjgastro.com, *2007 Journal Citation Report (Thomson Reuters, 2008)

The improvement of the resolution of rapid scanning in multidetector computed tomography (CT) has an increased accuracy that allows for the demonstration of the relationship of the pulmonary arteries and lung lesions, even in the peripheral lung. The purpose of this study is to evaluate the relationship between the pulmonary arteries and lung lesions by CT, and to use this relationship to distinguish between benign and malignant lung lesions. The relationships of the lung lesions and the adjacent pulmonary artery were recorded as encasement, displacement, penetration, in the margin, and disconnection. Statistical analyses were then performed to evaluate the relationship of the pulmonary arteries to each lesion with a focus toward the possibility of malignancy and the degree of pulmonary arterial encasement in the lesion. The relationship between the pulmonary arteries and lung lesions had a statistically significant difference between benignancy and malignancy (P < 0.001). Inter-observer agreement was substantial (κ = 0.639; 95% CI: 0.518-0.719). The average degrees of pulmonary arterial encasement in benign and malignant lesions were 52.1% ± 27.3% and 71.8% ± 18.8%, respectively (P = 0.011). The ROC curve showed that the degree of pulmonary arterial encasement had a moderate discriminating ability in diagnosing lung carcinoma, and the area under the curve was 0.738. The best cutoff value was 44.4%. The relationships of the pulmonary arteries to lung lesions and the degree of pulmonary arterial encasement could be used in differentiating benignancy from malignancy not only for central lung lesions but also peripheral lung lesions.

The objective of this study was to estimate the subsequent cancer risk of women after receiving hysterosalpingography (HSG) by conducting a nationwide retrospective cohort study. We identified a study cohort of 4371 patients who had had a HSG examination and a comparison cohort of 17, 484 women without HSG examination between 1998 and 2005. Both cohorts were followed up until the end of 2010 to measure the incidence of cancer. The risk of developing cancer for patients with HSG was assessed using the Cox proportional hazard model. In the multivariate analyses, the HSG cohort did not have a significantly greater risk of cancer (Hazard Ratio [HR] = 1.02, 95% CI = 0.79-1.31) than the non-HSG cohort. The HR was highest for genital cancer (HR = 1.32, 95% CI = 0.77-2.25), followed by urinary system cancer (HR = 1.11, 95% CI = 0.23-5.40), and abdominal cancer not involving the GU system (HR = 1.04, 95% CI = 0.53-2.03), all of which were non-significant elevations. The cancer incidence rates, especially that for urinary system cancer, were increased in the HSG cohort, but the increase in cancer incidence was small and not statistically significant.

To estimate the subsequent cancer risk of children receiving post voiding cystourethrography (VCUG), a nationwide population-based retrospective cohort study with the data from the Taiwan National Health Insurance Research Database (NHIRD) were used for the analysis. In the VCUG cohort, 31,908 participants younger than 18 years of age who underwent VCUG between 1997 and 2008 were identified from the NHIRD. A comparison cohort, the non-VCUG cohort, was randomly selected among children without VCUG examination histories during 1997-2008, frequency matched for age (every 5 years), sex, geographic region area, parents' occupation, and index year based on a 1:4 ratio. Cox's proportional hazard regression analysis was conducted to estimate the subsequent cancer risk of children receiving VCUG. The overall cancer risk of the VCUG cohort is 1.92-fold (95 % CI = 1.34-2.74) higher than that of the non-VCUG cohort with statistical significance. The genital cancer and urinary system cancer risks of the VCUG cohort are respectively 6.19-fold (95 % CI = 1.37-28.0) and 5.8-fold (95 % CI = 1.54-21.9) higher than those of the non-VCUG cohort with statistical significance. The hazard ratios are higher in genital cancer, urinary system cancer (the major radiation exposure area), and cancer of the abdomen, except for the genitourinary system (the minor radiation exposure area), in sequence. Pediatric VCUG is associated with increased subsequent cancer risk, especially in the genitourinary system.

The reproducibility of corticospinal diffusion tensor tractography (DTT) for a guideline is important before longitudinal monitoring of the therapy effects in stroke patients. This study aimed to establish the reproducibility of corticospinal DTT indices in healthy subjects and chronic hemiparetic stroke patients. Written informed consents were obtained from 10 healthy subjects (mean age 25.8±6.8 years), who underwent two scans in one session plus the third scan one week later, and from 15 patients (mean age 47.5±9.1 years, 6-60 months after the onset of stroke, NIHSS scores between 9 and 20) who were scanned thrice on separate days within one month. Diffusion-tensor imaging was performed at 3T with 25 diffusion directions. Corticospinal tracts were reconstructed using fiber assignment by continuous tracking without and with motion/eddy-current corrections. Intra- and inter-rater as well as intra- and inter-session variations of the DTT derived indices (fiber number, apparent diffusion coefficient (ADC), and fractional anisotropy (FA)) were assessed. Intra-session and inter-session coefficients of variations (CVs) are small for FA (1.13-2.09%) and ADC (0.45-1.64%), but much larger for fiber number (8.05-22.4%). Inter-session CVs in the stroke side of patients (22.4%) are higher than those in the normal sides (18.0%) and in the normal subjects (14.7%). Motion/eddy-current correction improved inter-session reproducibility only for the fiber number of the infarcted corticospinal tract (CV reduced from 22.4% to 14.1%). The fiber number derived from corticospinal DTT shows substantially lower precision than ADC and FA, with infarcted tracts showing lower reproducibility than the healthy tissues.

We propose a fully automated algorithm that is able to select a discriminative feature set from a training database via sequential forward selection (SFS), sequential backward selection (SBS), and F-score methods. We applied this scheme to microcalcifications cluster (MCC) detection in digital mammograms for early breast cancer detection. The system was able to select features fully automatically, regardless of the input training mammograms used. We tested the proposed scheme using a database of 111 clinical mammograms containing 1,050 microcalcifications (MCs). The accuracy of the system was examined via a free response receiver operating characteristic (fROC) curve of the test dataset. The system performance for MC identifications was Az = 0.9897, the sensitivity was 92%, and 0.65 false positives (FPs) were generated per image for MCC detection.

Lymphangioleiomyomatosis (LAM) is an extremely rare disease. It most commonly involves the lung; however, benign angiomyolipoma of the kidney may be present. Diffuse type LAM is even rarer. This report presents a case of lymphangi- oleiomyomatosis in bilateral lungs, kidneys, liver, retrocrural space and retroperitoneal space without stigmata of tuberous sclerosis.