The relationship between coronary artery calcification and myocardial perfusion in asymptomatic women.

BACKGROUND AND OBJECTIVES: No data are available in Saudi Arabia on the relationship between coronary artery calcification (CAC) and myocardial perfusion scintigraphy (MPS) in asymptomatic women, for determining subclinical coronary artery disease (CAD). The main objective of this study was to investigate the relationship between the presence of CAC and stress-induced myocardial ischemia by MPS in asymptomatic women. DESIGN AND SETTING: Single-center retrospective study over a 2-year period. METHODS: One hundred and one women (mean [SD] age, 56 [11] years) without known CAD underwent both MPS and CAC scanning within 3 months. The frequency of ischemia by MPS was compared with the presence or absence of CAC and the number of CAD risk factors. RESULTS: The prevalence of ischemic MPS was 22% (22/101). Among the 22 patients with ischemic MPS, the CAC score was 0 in 5 patients of 22 (23%), 1 to 200 in 4 patients of 22 (18%), and more than 200 in 13 patients of 22 (59%) (P=.0001). In contrast, among the 79 patients with normal MPS, the CAC score was 0 in 44 of 79 (56%) patients, 1 to 200 in 25 of 79 (32%), and more than 200 in 10 of 79 (13%). The presence or absence of CAC was the single most important predictor of the MPS result (P=.0001). CONCLUSIONS: Moderate to severe CAC is associated with ischemic MPS in more than 50% of asymptomatic women with 2 or more CAD risk factors. Abnormal MPS is rarely associated with a 0 CAC score. Normal MPS does not exclude subclinical CAD. Therefore, CAC screening is an appropriate initial screening test for CAD in asymptomatic women.

Clinical use of combined positron emission tomography and computed tomography in thymoma recurrence.

The aim of this study is to evaluate the efficacy of hybrid fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) for surveillance and follow-up of thymoma patients to detect recurrent disease. A retrospective chart review was performed on 37 thymoma patients who underwent FDG-PET/CT-scans during postoperative follow-up. The following information was obtained: clinical indication for FDG-PET/CT, the results of the FDG-PET/CT, particularly with regard to the additional diagnostic imaging information, the localization of the disease and subsequent clinical patient management. A total of 51 CT-scans were performed on 37 patients providing sensitivity and specificity for thymoma recurrence of 71% and 85%, respectively. Forty-five FDG-PET/CT-scans were performed on the same group of patients with an overall sensitivity and specificity of 82% and 95%, respectively. Notably, FDG-PET/CT sensitivity when employed for diagnosis of thymoma recurrence in the anterior mediastinum has reached 100% (CT has shown only 55% sensitivity for the detection of anterior mediastinal thymoma recurrence). Our preliminary study demonstrates that during follow-up after thymoma excision, FDG-PET/CT is superior to computed tomography alone in the detection and localization of mediastinal recurrence. In particular, the combined structural and metabolic information of FDG-PET/CT enhances the diagnostic confidence in lesion characterization.

18F-FDG imaging: pitfalls and artifacts.

18F-FDG PET is emerging as a useful tool in the staging and restaging of many malignant neoplasms, such as lymphoma, lung cancer, colorectal cancer, head and neck cancer, breast cancer, and melanoma. To accurately interpret 18F-FDG findings one must be familiar with the normal physiologic distribution of the tracer, frequently encountered physiologic variants, and benign pathologic causes of 18F-FDG uptake that can be confused with a malignant neoplasm. The objectives of this article are to (a) describe the mechanism of 18F-FDG uptake, (b) list the patient preparation and pertinent patient history before 18F-FDG imaging, (c) describe the whole-body physiologic distribution of 18F-FDG, (d) list and discuss normal physiologic variants, and (e) list and discuss benign pathologic causes of 18F-FDG uptake.