Fasciola Hepatica Mimicking Malignancy on 18F-Fluorodeoxyglucose-Positron Emission Tomography/Computed Tomography.

A 48-year-old female with complaints of gastrointestinal symptoms such as abdominal pain, fatigue, vomiting, nausea, and weight loss was diagnosed with neuroendocrine tumor after removal of a 2 mm lesion from the stomach with endoscopic biopsy. Her magnetic resonance imaging that was performed due to on-going symptoms showed multiple linear hypointense lesions in the liver. Positron emission tomography/computed tomography (PET/CT) scan was performed for differential diagnosis, which showed high fluorodeoxyglucose (FDG) uptake in these lesions. Clinical and laboratory findings revealed the final diagnosis as Fasciola hepatica. The imaging features of this case is presented to aid in differentiating this infectious disease from malignancy and avoid misdiagnosis on FDG-PET/CT.

Validation of 18F-fluoro-4-thia-palmitate as a PET probe for myocardial fatty acid oxidation: effects of hypoxia and composition of exogenous fatty acids.

UNLABELLED: Fatty acid oxidation (FAO) is the predominant energy-producing pathway in the healthy heart. Abnormalities in FAO are associated with many ischemic and nonischemic disease states. The aim of the present study was to further validate 16-[(18)F]-fluoro-4-thia-palmitate ((18)F-FTP) as a metabolically trapped FAO probe in the isolated perfused rat heart model by examining both the effects of hypoxia and the effects of changes in exogenous fatty acid availability. METHODS: Hearts were excised from Sprague-Dawley rats and perfused in the Langendorff mode with Krebs-Henseleit solution under the following conditions: palmitate at 0.4 mmol/L with 95% oxygen, palmitate at 0.4 mmol/L with 35% oxygen, palmitate at 0.2 mmol/L plus oleate at 0.2 mmol/L with 95% oxygen, and palmitate at 0.2 mmol/L plus oleate at 0.2 mmol/L with 35% oxygen. Hearts were paced at 270 beats per minute, and the rate of left ventricular pressure change (LV dP/dt) was monitored. (18)F-FTP in the perfusion medium was administered for 20 min, and this step was followed by a 20-min washout period without tracer in the perfusion medium. (18)F kinetics in the whole heart were monitored externally, and the time-activity curves were analyzed to determine the fractional trapping rate for (18)F-FTP (FTR(FTP)). A "lumped constant" (LC) was defined as the ratio of FTR(FTP) to the fractional rate of oxidation of fatty acid in the perfusion medium. RESULTS: The kinetic data for (18)F-FTP demonstrated metabolic trapping of (18)F radioactivity that was insensitive to changes in the mixture of fatty acids in the perfusion medium but that was sensitive to the inhibition of mitochondrial FAO by hypoxia. LV dP/dt was reduced 47%-67% in hypoxic hearts relative to hearts with normal oxygenation (controls). FAO rates for palmitate and oleate were similar in group 3 (palmitate alone) and group 4 (palmitate and oleate). FAO was decreased 70%-76% with hypoxia, whereas FTR(FTP) was reduced 86%-88%, demonstrating hypersensitivity of a change in (18)F-FTP retention to FAO inhibition by oxygen deprivation. The (18)F-FTP LC was approximately 2 in myocardium with normal oxygenation and fell to 1.0-1.2 in hypoxic myocardium. CONCLUSION: The results confirm (18)F-FTP to be a metabolically trapped palmitate analog that is capable of indicating rates of myocardial oxidation of exogenous long-chain fatty acids. The heterogeneous nature of fatty acids in plasma does not alter the quantitative analysis of (18)F-FTP kinetics. However, the decreased LC value in hypoxic myocardium suggests the need to develop an understanding of the relationship of (18)F-FTP processing to natural fatty acids at key limiting transport and metabolism processes, analogous to previous studies examining the LC values for radiolabeled deoxyglucose tracers used to estimate the glucose metabolic rate.

Reliability of Web-based teledermatology consultations.

We studied the reliability of teledermatology diagnoses made using a Web-based system. Clinical photographs and information relating to 125 patients were placed on a Web server. Three dermatologists made the most likely diagnosis via a Web interface. The reference diagnosis was made in a face-to-face consultation with a fourth dermatologist; where appropriate it was confirmed histologically. The teledermatologists were correct in 57% of cases when viewing the images alone. Their diagnostic accuracy improved to 70% when additional clinical information was available. The rate of agreement between the teledermatologists ranged from 44% to 70% (kappa= 0.22-0.32). Seventy-seven per cent of the patients were correctly diagnosed by at least two dermatologists when clinical information was provided. A Web-based system appears to be reliable for teledermatology. A single well trained teledermatologist may give better results than a group of less well trained clinicians.

Dobutamine Tc-99m furifosmin SPECT in detection of coronary artery disease: evaluation of same day, rest-stress protocol.

The purpose of this study was to evaluate the feasibility and diagnostic accuracy of same day rest-stress myocardial perfusion SPECT (MP SPECT) protocol by using technetium-99m (Tc-99m) furifosmin in conjunction with dobutamine stress test in subjects in whom coronary artery disease (CAD) had been proven or excluded at coronary angiography (CA). The study group consisted of 25 patients (8 female and 17 male with a mean age of 53.04 +/- 8.56 yrs) unable to perform treadmill exercise or unsuitable for pharmacologic vasodilator stress testing. Ten mCi (370 MBq) of Tc-99m furifosmin was injected intravenously at rest. Sixty min after injection, planar and SPECT images were acquired. One hour later all patients underwent dobutamine stress test. At the peak stress, 20 mCi (740 MBq) of Tc-99m furifosmin was injected. Sixty min after stress dose injection, planar and SPECT images were acquired. Rest-stress planar and SPECT data were evaluated by using visual and quantitative analysis. Heart to adjacent organ (Heart/Lung; H/Lu and Heart/Liver; H/Li) activity ratios were calculated from anterior planar images by using regions of interest (ROI). SPECT data were interpreted by using 20 segment-5 point scoring system from short axis and vertical long axis slices. The results of rest-dobutamine stress Tc-99m furifosmin MP SPECT were compared with CA results. There were statistically significant differences between H/Lu and H/Li ratios at rest and stress conditions. Heart/adjacent organ activity ratios were similar and significant statistical difference could not be found between CA positive and CA normal patients. Sensitivity, specificity and accuracy for Tc-99m furifosmin SPECT study were calculated as 90%, 80% and 84% for left anterior descending (LAD), 87%, 94% and 92% for left circumflex (LCx) and 67%, 86% and 80% for right coronary artery (RCA), respectively. Overall sensitivity, specificity and accuracy were calculated as 83%, 87% and 85%, respectively. According to the results obtained in this study, it may be concluded that same day rest-dobutamine stress Tc-99m furifosmin SPECT protocol is a feasible and accurate technique in the evaluation of CAD, especially in patients unable to perform treadmill exercise or unsuitable for pharmacologic vasodilator stress testing.

Thallium-201 myocardial SPECT in a patient with mirror-image dextrocardia and left bundle branch block.

A 53-year-old male patient with a previous diagnosis of situs inversus with mirror-image dextrocardia underwent thallium-201 (Tl-201) stress-redistribution myocardial perfusion single photon emission computed tomography (SPECT). Electrocardiogram (ECG) obtained on right hemithorax revealed constant complete left bundle branch block. Tl-201 stress-redistribution SPECT images revealed abnormal perfusion with reversible ischemia in the anteroseptal, septal and inferoseptal walls. Coronary angiography performed 1 month after SPECT study was normal. This case illustrates that false positive reversible perfusion defects can be seen in patients with mirror-image dextrocardia associated with constant complete left bundle branch block. To our knowledge, this is the first reported case of mirror-image dextrocardia and constant complete left bundle branch block with false positive Tl-201 SPECT findings.

Incidental detection of pigmented villonodular synovitis on FDG PET.

18 Fluorine fluorodeoxyglucose (FDG) has been used extensively in positron emission tomographic (PET) imaging for oncology. FDG is a glucose analog demonstrating enhanced uptake in the majority of malignant as well as granulomatous lesions. Although a few cases of pigmented villonodular synovitis using bone scanning agents Tl-201 chloride, Ga-67 citrate, and Tc-99m pentavalent dimercaptosuccinic acid have been published, to our knowledge FDG PET imaging of pigmented villonodular synovitis has not.