Hepatic tuberculosis: a rare cause of fluorodeoxyglucose hepatic superscan with background suppression on positron emission tomography

Fluorodeoxyglucose (FDG) hepatic superscan refers to the diffuse intense uptake of 18F-FDG in the liver on positron emission tomography (PET), with reduced physiological activity in the brain and heart. The common causes include lymphoma and metastasis. In this case report, we describe the imaging features of tuberculosis as a rare cause of FDG hepatic superscan. PET imaging may be the only clue to a diagnosis of hepatic tuberculosis, as other imaging modalities may demonstrate only nonspecific hepatomegaly. It is important to consider this entity in the differential diagnosis of patients presenting with FDG hepatic superscan and proceed with liver biopsy for a definitive diagnosis.

Experimental Evaluation of Accelerated T1rho Relaxation Quantification in Human Liver Using Limited Spin-Lock Times

OBJECTIVE: It was reported lately that to obtain consistent liver T1rho measurement, at 3T MRI using six spin-lock times (SLTs), is feasible. In this study, the feasibility of using three or two SLT points to measure liver T1rho relaxation time was explored. MATERIALS AND METHODS: Seventeen healthy volunteers underwent 36 examinations. Three representative axial slices were selected to cut through the upper, middle, and lower liver. A rotary echo spin-lock pulse was implemented in a 2D fast field echo sequence. Spin-lock frequency was 500 Hz and the spin-lock times of 1, 10, 20, 30, 40, and 50 milliseconds (ms) were used for T1rho mapping. T1rho maps were constructed by using all 6 SLT points, three SLT points of 1, 20, and 50 ms, or two SLTs of 1 and 50 ms, respectively. Intra-class correlation coefficient (ICC) and Bland and Altman plot were used to assess the measurement agreement. RESULTS: Two examinations were excluded, due to motion artifact at the SLT of 50 ms. With the remaining 34 examinations, the ICC for 6-SLT vs. 3-SLT T1rho measurements was 0.922, while the ICC for 6-SLT vs. 2-SLT T1rho measurement was 0.756. The Bland and Altman analysis showed a mean difference of 0.19 (95% limits of agreement: -1.34, 1.73) for 6-SLT vs. 3-SLT T1rho measurement, and the mean difference of 0.89 (95% limits of agreement: -1.67, 3.45) for 6-SLT vs. 2-SLT T1rho measurement. The scan re-scan reproducibility ICC (n = 11 subjects) was 0.755, 0.727, and 0.528 for 6-SLT measurement, 3-SLT measurement, and 2-SLT measurement, respectively. CONCLUSION: Adopting 3 SLTs of 1, 20, and 50 ms can be an acceptable alternative for the liver T1rho measurement, while 2 SLTs of 1 and 50 ms do not provide reliable measurement.

Characteristics of rat lumbar vertebral body bone mineral density and differential segmental responses to sex hormone deficiency: a clinical multidetector computed tomography study / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To investigate sex hormone deficiency related osteoporosis and efficacy of different therapies.</p><p><b>METHODS</b>Orchiectomized and ovariectomized rat models are used to investigate sex hormone deficiency related osteoporosis and efficacy of different therapies. A rat vertebral body can be longitudinally divided into central portion, which contain more trabecular bone, and para-endplate portions which contain more compact bone. In matured male and female Wistar and Sprague-Dawley rat lumbar spines, we investigated baseline bone mineral density (BMD) characteristics and the differential segmental responses in bone loss within the lumbar vertebral body post gonadal surgery with clinical multidetector computed tomography.</p><p><b>RESULTS</b>Para-endplate sections had a higher BMD than central sections. The cephalad para-endplate sections had a higher BMD than the caudad para-endplate sections. Eight weeks after gonadal removal, there was more bone loss in central sections than para-endplate sections. The relative difference of bone loss between para-endplate and central sections was more apparent in male rats than in female rats. There was more bone loss in caudad sections than cephalad sections; this lead to a further increase of BMD difference between caudad para-endplate sections and cephalad para-endplate sections post gonadal surgery.</p><p><b>CONCLUSION</b>The approach described in this study provided a consistent way to study BMD change within predominantly compact bone portion and trabecular bone portion of the vertebral body.</p>