Wilson T. Lao

Inflammatory pseudotumor of the spleen: CT and MRI findings.

We report the CT and MRI findings of an inflammatory pseudotumour of the spleen, which is an extremely rare benign inflammatory lesion. CT scans obtained 1 h after contrast administration and T2-weighted MRI images clearly demonstrated the central fibrosis and peripheral granuloma of this lesion.Inflammatory pseudotumors rarely occur in the spleen. We report such a case with characteristic computed tomography (CT) and magnetic resonance imaging (MRI) findings. A CT scan showed an isodense nodular mass with gradual mild enhancement on delayed-phase contrast-enhanced images. MRI showed a mass with isointense signal on T1-weighted images and hypointense signal on T2-weighted images. The tumor mass showed progressive inhomogeneous enhancement on gadolinium-enhanced images. The patient received splenectomy, and histologic diagnosis was compatible with inflammatory pseudotumor.

MRI of hemangiopericytoma in the sacrum

Osseous hemangiopericytoma is rare. We present a case of a 30-year-old woman with low-back pain with radiation to the left buttock for 1 month. Magnetic resonance imaging (MRI) showed a tumor mass with areas of serpentine signal void pattern in the sacrum suggestive of a vascular tumor. Neither calcifications nor layered blood serum were noted. Histological diagnosis was compatible with osseous hemangiopericytoma.

Follicular dendritic cell sarcoma of the omentum: multidetector computed tomography findings.

We report computed tomography (CT) findings for a rare case of follicular dendritic cell sarcoma of the greater omentum from a 47-year-old female patient. The tumor presented ash a palpable mass lesion in the umbilical region for the last two months. Multidetector CT scan of the abdomen showed a 14-cm soft-tissue mass with calcification and necrosis within the greater omentum. As a result, a follicular dendritic cell sarcoma should be considered in the differential diagnosis of a solitary omentum mass, especially one with coarse and chunk-like calcifications.

Practice Standards Developed and Quality Improvement for Use of Coronary CT Angiography in Taiwan

BACKGROUND Coronary artery disease (CAD) has been the second most common cause of death in Taiwan over the past 10 years. The mortality rate has increased 8.1% from 2015 (81.8 per 100,000) to 2016 (88.5 per 100,000) as a result of aging [1]. Most patients with CAD are asymptomatic; early detection and treatment can reduce the incidence of acute myocardial infarction [2,3]. Recent advances in medical technology (such as CT tomography angiography [CCTA]) have improved detection of coronary arterial stenosis by increasing image quality, lowering radiation exposure, and being less invasive [4-6]. To avoid inappropriate invasive coronary angiography, CCTA with at least 64 slices can be used to rule out obstructive coronary stenoses [7]. Standardization for CCTA use in screening asymptomatic patients and diagnosing symptomatic patients with CAD risk is lacking in Taiwan. Our aim was to develop standards of practice and evaluate their performance at our hospital.

The proper use of coronary calcium score and coronary computed tomography angiography for screening asymptomatic patients with cardiovascular risk factors

Early detection and treatment of coronary artery disease (CAD) can reduce incidences of acute myocardial infarction. In this study, we determined the proper use of contributing risk factors and coronary artery calcium score (CACS) when screening asymptomatic patients with coronary arterial stenoses using coronary computed tomography angiography (CCTA). We reviewed 934 consecutive patients who received CACS and CCTA between December 2013 and November 2016. At least one cardiovascular disease risk factor was present in each of the 509 asymptomatic participants. Patients were grouped based on CACS into “zero,” “minimal” (0 < CACS ≤ 10), “mild” (10 < CACS ≤ 100), “moderate” (100 < CACS ≤ 400), and “excessive” (CACS > 400). Males over 45 years old with diabetes mellitus and hypertension had a higher risk of significant coronary stenosis. In multivariate analysis, age, sex, hypertension, and diabetes mellitus remained significant predictors of stenosis. A CACS of zero occurred in 227 patients (44.6%). There were no significant differences between the “zero” and “minimal” groups (p = 0.421), but the “mild,” “moderate,” and “excessive” groups showed correlations with significant coronary stenosis. Age, sex, diabetes mellitus, and hypertension were associated with higher risk of significant coronary stenosis. Asymptomatic patients with CACSs of zero do not require CCTA, and thereby avoid unnecessary radiation exposure.

Assessment of radiation safety in cardiac CT angiography

Abstract This study investigates the radiation dose and image quality of patients not receiving &bgr;-blockers for cardiac CT angiography (CCTA) with or without the optimization of electrocardiographic (ECG) pulsing window. The differences in patient characteristics are also characterized. Normal-weight and obese patients (n = 154) with heart rates between 65 and 80 beats per minutes (bpm) during the prospective axial scanning were enrolled retrospectively. The ECG pulsing windows were set at 50% to 75% (Group A) or 60% to 75% (Group B) of the R-R interval for patients with heart rate variability higher than or not exceeding ±5 bpm, respectively. The effective doses of individual patient were estimated from the dose length product of the CCTA scan. Two radiologists independently reviewed the images and applied a 4-point Likert scale for image quality assessment. The patients’ characteristics were compared along with the patients’ effective doses between groups. The optimized pulsing window significantly reduced the average radiation dose for normal-weight and obese patients by 33% and 27%, respectively. The CCTA image quality of patients in Group A was not different overall from those obtained from Group B. Nondiabetic obese patients were more likely to be accepted for the use of the optimized pulsing window. Unlike obese patients, normal-weight patients revealed no characteristic difference between Groups A and B. This study indicates an equivalent efficacy of using optimized pulsing windows for reducing the radiation dose for patients without &bgr;-blocker administration between different body weight groups. Nevertheless, gender and diabetic status became prominent characteristics in the obese group when matching up with the optimized pulsing window.

Laparoscopy-Associated Inferior Mesenteric Vein Thrombosis

Inferior mesenteric vein thrombosis is a rare complication after laparoscopic procedures. We presented a case of a 55-year-old woman who suffered from abdominal pain for two days. She received laparoscopic left hemicolectomy for sigmoid colon cancer two weeks ago. Computed tomography scan revealed a thrombus of the inferior mesenteric vein. The patient was managed conservatively in hospital. Her condition improved gradually without further symptoms and she was discharged after two weeks.