Quantification of Muscle Metabolites Using Proton Magnetic Resonance Spectroscopy (1 H-MRS) for Incomplete Spinal Cord Injury Patients: Preliminary Study

@#Introduction: This preliminary study aimed to non-invasively evaluate choline (CHO), creatine (Cr) and intramyocellular lipid (IMCL) metabolites in skeletal muscles at pre- and post-functional electrical stimulation (FES) exercise among incomplete spinal cord injury (SCI) of American Spinal Injury Association Impairment Scale (ASIA-AIS) D patients using proton magnetic resonance spectroscopy or 1 H-MRS. Methods: These metabolites were measured from the vastus lateralis and semitendinosus muscles of three incomplete SCI ASIA-AIS D patients who completed the FES exercise and later underwent 3 Tesla (T) MRI (repetition time/echo time; TR/TE of 3500ms/100ms, field-ofview; FOV of 20cm, slice thickness of 6mm) and 1 H-MRS (TR/TE of 2000ms/31ms, voxel size of 20mm x 20mm x 35mm). Results: Out of those selected metabolites, only CHO value of vastus lateralis showed a statistically significant difference between pre- and post FES exercise 1 H-MRS scanning (p = 0.01). Conclusion: Therefore, this preliminary finding has postulated that the quantification of muscle metabolites using 1 H-MRS imaging could be used as a potential indicator in evaluating the muscle strength for incomplete SCI ASIA-AIS D patients after the completion of FES cycling exercise.

Delayed Dual-Time Point Imaging Protocol Improving Myocardial Uptake of 18-Fluorine Flouro Deoxyglucose (18F-FDG) During Viability Screening of Diabetes Mellitus Type 2 Patients Using Integrated Positron Emission Tomography/Computed Tomography (PET/CT) Imaging.

Aims: To investigate the effect of delayed imaging protocol and hypoglycemic agent on quantitative values obtained during myocardial viability 18F-FDG PET/CT assessment. Presentation of Case: Mr. A, a 72 year-old man, Madam B, a 73 year-old woman and Madam C, a 64 year-old woman, presented to the Centre for Diagnostic Nuclear Imaging, Universiti Putra Malaysia for myocardial viability assessment. All were diagnosed Diabetes Mellitus type II on oral hypoglycemic agent. Discussion: Our study showed an increased 18F-FDG uptake in the wall of LV after the delayed protocol was applied to the patients. One hour time elapsed before 18F-FDG injection is to allow optimal level of niacin in the blood for its action to lower the plasma FFA levels and encourage myocardial preference towards glucose metabolism. Oral glucose loading is given to stimulate insulin secretion and increase glucose utilization as the metabolic substrate. The approach of premedicating nicotinic acid like niacin can be a reliable hypolipidemic agent in shifting myocardial metabolism to glucose oxidative pathway in 18F-FDG PET/CT myocardial viability assessment. Delayed enhancement imaging has been shown to be effective, in both animals and humans, in identifying the presence, location, and extent of acute and chronic myocardial infarction in patients with ischemic cardiomyopathy. Furthermore, this technique may also be useful in assessing myocardial injury in patients with non-ischaemic heart disease. Conclusion: Delayed imaging is superior to early imaging. The improvement of the image quality leads to accurate assessment of the viable or non-viable myocardium.

Molecular imaging of plaques in coronary arteries with PET and SPECT / 老年心脏病学杂志（英文版）

Coronary artery disease remains a major cause of mortality. Presence of atherosclerotic plaques in the coronary artery is responsible for lu-men stenosis which is often used as an indicator for determining the severity of coronary artery disease. However, the degree of coronary lumen stenosis is not often related to compromising myocardial blood flow, as most of the cardiac events that are caused by atherosclerotic plaques are the result of vulnerable plaques which are prone to rupture. Thus, identification of vulnerable plaques in coronary arteries has become increas-ingly important to assist identify patients with high cardiovascular risks. Molecular imaging with use of positron emission tomography (PET) and single photon emission computed tomography (SPECT) has fulfilled this goal by providing functional information about plaque activity which enables accurate assessment of plaque stability. This review article provides an overview of diagnostic applications of molecular imaging tech-niques in the detection of plaques in coronary arteries with PET and SPECT. New radiopharmaceuticals used in the molecular imaging of coro-nary plaques and diagnostic applications of integrated PET/CT and PET/MRI in coronary plaques are also discussed.

Brown fat uptake of 18F-FDG on dual time point PET/CT imaging

The aim of this report was to assess the changes in the 18F-fluorodeoxyglucose (18F-FDG) uptake of brown fats on integrated positron emission tomography/computed tomography (PET/CT) imaging. The patient presented with an enlargement of the neck lymph nodes, and was suspicious for tuberculous lymphadenitis. A whole body PET/CT imaging was performed, followed by a delayed imaging of the neck and thoracic regions. A visually increased 18F-FDG uptake was taken as a positive finding. A semi-quantitative evaluation was performed using a maximum standardised uptake value (SUVmax), with a cut-off value above 2.5. There were a number of 18F-FDG avid activity areas seen at the supraclavicular, mediastinal, paravertebral and perirenal regions. These are in keeping with the physiological 18F-FDG uptake in brown fat. The differences in SUVmax between the two images ranged from -20 percent to +20 percent. Based on our observations, dual time point imaging may not be a reliable method for assessing the 18F-FDG uptake of brown fat.