Cardiac CT angiography compared with myocardial perfusion stress testing on downstream resource utilization.

BACKGROUND: Nuclear myocardial perfusion stress (MPS) testing and cardiac computed tomographic angiography (CCTA) are commonly used noninvasive tests. Limited studies exist comparing their clinical and cost outcomes. OBJECTIVES: We compared the clinical and cost outcomes of MPS with CCTA in a symptomatic cohort. METHODS: We retrospectively identified 241 symptomatic patients without known coronary artery disease (CAD) who underwent MPS between May 2006 and April 2008. A comparison group of 252 age- and sex-matched symptomatic patients without known CAD underwent 64-slice CCTA during the same period. The primary outcome was the per-patient rate of posttest clinical evaluations and cardiac testing for the presenting symptom. Total direct costs were also compared. RESULTS: The group consisted of 44% women of mean age 53 ± 10 years. There were no differences in risk factors or pretest probability of obstructive CAD (83% intermediate risk) between groups. During mean follow-up of 30 ± 7 months, we found no difference between CCTA and MPS in per-patient rates of any posttest evaluation or testing, 24.6% versus 27.7% (P = 0.44), respectively. CCTA patients had lower utilization of invasive angiography (3.3% vs 8.1%; P = 0.02) and a nonsignificant trend toward reduced downstream cardiac testing (11.5% vs 17.0%; P = 0.08). Including the evaluation of significant incidental findings (7.1% in CCTA), mean direct costs were significantly lower using CCTA ($808; 95% CI, $611-$1005) compared with MPS ($1315; 95% CI, $1105-$1525; P <0.001). CONCLUSIONS: Low-intermediate risk patients without known CAD who underwent CCTA, compared with MPS, had similar rates of posttest evaluations, fewer invasive catheterizations, and lower overall evaluation costs.

The added benefit of a dedicated neck F-18 FDG PET-CT imaging protocol in patients with suspected recurrent differentiated thyroid carcinoma.

PURPOSE: To retrospectively analyze whether adding a delayed high-resolution dedicated neck F-18 FDG positron emission tomography-computerized tomographic (PET-CT) imaging protocol in patients with recurrent differentiated thyroid cancer increases the number of abnormal foci within the neck. MATERIALS AND METHODS: Seventeen PET-CT studies from a total of 10 patients with suspected recurrent differentiated thyroid cancer between March 2003 and June 2004 were retrospectively reviewed. Each study included a whole body acquisition (WBA), followed by higher resolution dedicated neck acquisition (DNA). Two board-certified nuclear medicine physicians reviewed either the DNA or WBA for each study and recorded the number of abnormal foci, along with presence or absence of a soft tissue abnormality, and maximum standardized uptake value for each foci. Consensus review was used for all discrepancies. Statistical analysis was performed to determine whether there was a statistically significant increase in the number of studies demonstrating new abnormal foci with the addition of a DNA. RESULTS: Five of 17 studies demonstrated an increase in the number of abnormal foci with the addition of the DNA (P < 0.04). A total of 8 abnormal foci were noted on the WBA, 4 of which were within the neck. Eleven additional abnormal foci were seen on the DNA. All abnormal foci within the neck had corresponding soft tissue abnormalities except for one. CONCLUSION: Adding a higher resolution delayed DNA to the WBA for patients undergoing PET-CT imaging to detect recurrent thyroid cancer increases the number of abnormal sites of FDG accumulation.

Low-iodine diet revisited: importance in nuclear medicine imaging and management.

PURPOSE: The need for a low-iodine diet (LID) to maximize the results of radioactive iodine uptake (RAIU), nuclear medicine thyroid scintigraphy, and ultimately treatment of thyroid cancer patients is widely accepted. Failure to follow the prescribed diet can alter RAIU results, thyroid scan findings, and poststudy management. OBJECTIVE: Provided is a case presentation that illustrates the need for adequate patient understanding and compliance with the LID. METHODS: We present the clinical history, laboratory values, and pertinent imaging of a 21-year-old woman with papillary thyroid cancer. The patient's post-thyroidectomy I-123 and 2 subsequent thyroid (I-123 and post-RAI ablation I-131) scintigraphy examinations are reviewed as well as the patient's urine iodine levels. RESULTS: In this case of a woman with papillary thyroid cancer, the nuclear medicine whole body and neck pinhole images revealed that compliance to an LID positively impacts the overall management. After an LID was followed, the patient's urine iodine level appropriately declined from the previously elevated level. Initial negative results on thyroid scintigraphy caused by noncompliance with the LID became positive when the patient adhered to the prescribed dietary regimen. CONCLUSION: An LID is an integral element in the management of differentiated thyroid cancer. Proper guidance and emphasis on the implementation of the diet needs to be provided to patients. Noncompliance may lead to false negative imaging results, misleading the medical professionals and patient. Potentially inadequate management of the patient's thyroid cancer may follow.