Incremental prognostic value of RNA ejection fraction measurements during pharmacologic stress testing: a comparison with clinical and perfusion variables.

UNLABELLED: This investigation examined the prognostic power of first-pass radionuclide angiocardiography (RNA) ejection fraction compared with clinical information and myocardial perfusion imaging in patients undergoing pharmacologic stress testing. The value of RNA and myocardial perfusion imaging in predicting death or nonfatal myocardial infarction (MI) is well established. However, limited information exists on the usefulness of combined myocardial perfusion imaging and RNA to predict prognosis, especially in patients undergoing pharmacologic stress testing. METHODS: We identified 240 patients who underwent pharmacologic stress testing with myocardial perfusion imaging and combined RNA. The patients were followed for a mean of 1.4 y. Cox proportional hazards models were used to assess the value in predicting death and MI. Multivariable models were generated to assess the independent incremental predictive value of clinical and nuclear imaging variables. Kaplan-Meier survival and event-free survival estimates were examined in patients with low (< or = 45%) versus high (>45%) ejection fractions. RESULTS: Clinical information, myocardial perfusion imaging, and RNA ejection fraction were significant predictors of the death/MI composite outcome (chi(2) = 7.4, 14.0, and 21.8, respectively). The addition of myocardial perfusion imaging to the clinical information provided incremental prognostic information (chi(2) = 15.2). The addition of RNA ejection fraction provided further predictive information (chi(2) = 22.5). However, when RNA ejection fraction was first added to the clinical information, myocardial perfusion imaging had no incremental prognostic value. CONCLUSION: For hard cardiac events, RNA ejection fraction provides prognostic information besides that provided by clinical and myocardial perfusion imaging. In patients who cannot exercise and are undergoing noninvasive evaluation with pharmacologic stress testing and myocardial perfusion imaging, ejection fraction should be measured simultaneously for risk assessment optimization.

Efficiency comparison between 99m Tc-tetrofosmin and 99m Tc-sestamibi myocardial perfusion studies.

The purpose of this investigation was to compare the efficiency of two different imaging protocols using two different clinically available 99mTc labelled myocardial perfusion tracers. One thousand one hundred and thirty-four imaging studies were performed prospectively, using either 99mTc-tetrofosmin or 99mTc-sestamibi, alternating the use of each tracer for a total period of 8 months. 99mTc-tetrofosmin rest studies were performed with injections of 259MBq-370MBq and imaging 30 min later. Exercise studies were performed with injections of 777MBq-1.11GBq and imaging 20 min later. 99mTc-sestamibi studies used doses similar to those in the 99mTc-tetrofosmin studies. Imaging followed a standard procedure, at 60 min after rest injection, and 30 min after exercise. For patients undergoing pharmacological stress testing99mTc-sestamibi was imaged 45 min after injection and 99mTc-tetrofosmin was imaged 30 min after injection. Variables analysed were (1) injection-to-imaging time for the procedure, and (2) the number of repeated scans because of extra cardiac activity. The completion time for the rest study was significantly shorter for 99mTc-tetrofosmin compared to 99mTc-sestamibi (47.7+/-21.7 min vs 74.3+/-25.8 min P<0.0001). Likewise, the total study time was shorter for 99mTc-tetrofosmin compared to 99mTc-sestamibi (90+/-32.7 min vs 124+/-37 min, P<0.0001). More importantly, the number of repeated scans was higher with 99mTc-sestamibi compared to 99mTc-tetrofosmin, 21.4% vs 10%, P=0.001 for rest studies and 16.4% vs 7.9% P=0.001 [corrected] for rest and stress. It was concluded that, using a same day rest/stress protocol, 99mTc-tetrofosmin provided higher patient throughput with fewer repeat scans. These factors may be considered for efficiency improvement in nuclear cardiology laboratories using 99mTc perfusion tracers.

Whole-body Tc-99m sestamibi scintigraphy in the follow-up of differentiated thyroid carcinoma.

PURPOSE: This study evaluated the potential of Tc-99m sestamibi whole-body scan (WBMIBI) as an alternative to whole-body I-131 scan (WBI) for the follow-up of patients with differentiated thyroid carcinoma. MATERIALS AND METHODS: We evaluated 99 consecutive patients with differentiated thyroid carcinoma who had total or nearly total thyroidectomy followed by an ablative dose of I-131 (86 women, 13 men; mean age, 44 +/- 12 years). WBMIBI was performed and serum thyroglobulin (TG) levels were obtained at least 6 months after I-131 treatment. All persons were receiving levothyroxine therapy. RESULTS: From the total of 110 studies performed, WBMIBI and TG were in agreement in 96% and discordant in 4%. From the 27 crossed studies (WBMIBI x TG) with at least one abnormal result, 16 were compared with WBI. In four cases, the WBI did not reveal functioning thyroid tissue when both TG and WBMIBI indicated tumoral activity. In one case of pulmonary metastasis confirmed by chest radiographs, with a normal TG value, the results of both WBMIBI and WBI were positive. CONCLUSIONS: WBMIBI should be considered as a scintigraphic method in the follow-up of differentiated thyroid carcinoma. This technique can show the sites of tumoral activity with optimal image resolution, particularly in those with abnormal TG and negative WBI results, and it is a potentially valuable tool in patients with anti-TG antibodies. The WBI in patients having ablation should be reserved only for therapy planning.

Imaging of bladder cancer: update on current approaches for diagnosis.

Imaging plays a mainstay role in evaluation of patients with bladder cancer, especially for diagnosis, local and distant staging and treatment follow up. In this article, we aim to review and to update conventional and functional imaging methods used in clinical management of bladder cancer.

The evolving role of nuclear molecular imaging in cancer.

BACKGROUND: Novel therapies targeted to specific tumor pathways are entering the clinic. The need for in vivo monitoring of resulting molecular changes, particularly with respect to the tumor microenvironment, is growing. Molecular imaging is evolving to include a variety of imaging methods to enable in vivo monitoring of cellular and molecular processes. OBJECTIVES: This article reviews the emerging role of molecular imaging in the development of improved therapeutic strategies that provide better patient selection for therapeutic personalization (i.e. determine which therapies have the greatest chance of success given the individual patient's disease genetic, and phenotypical profile). METHODS: In order to illustrate the utility of integrating molecular imaging into therapy development strategies, current and emerging applications of nuclear molecular imaging strategies will be compared with conventional strategies. Proposed methods of integrating molecular imaging techniques into cancer therapeutic development and limitations of these techniques will be discussed. RESULTS/CONCLUSION: Molecular imaging provides a variety of new tools to accelerate the development of cancer therapies. The recent drive to develop molecular imaging probes and standardize molecular imaging techniques is creating the scaffolding for the evolving paradigm shift to personalized cancer therapy.

Poststress measurements of left ventricular function with gated perfusion SPECT: comparison with resting measurements by using a same-day perfusion-function protocol.

PURPOSE: To investigate the relationship between the development of ischemia during stress testing and the changes in left ventricular ejection fraction (LVEF) measurements obtained after stress and at rest with a same-day perfusion-function imaging protocol. MATERIALS AND METHODS: One hundred twenty-six patients underwent a same-day rest-stress (61%) or stress-rest (39%) protocol and gated single photon emission computed tomography (SPECT). Perfusion analysis was performed with a 12-segment model. Defects were scored (0 = no defect, 1 = mild defect, 2 = moderate defect, and 3 = severe defect); differences between the summed stress and resting scores of greater than three indicated substantial ischemia. RESULTS: Resting and poststress LVEFs correlated significantly (r = 0.97, P <.001); however, patients with and patients without ischemia had significant differences in poststress versus resting LVEFs (-4.0 vs 1.0, respectively; P <.01). In patients with ischemia versus patients without ischemia, subgroup analysis stress-rest (-2.5 vs 1.0, P =.047) and rest-stress (-4.0 vs 1.0, P =.006) protocols yielded similar results. CONCLUSION: In patients with clinically important stress-induced perfusion abnormalities, the LVEF after stress was significantly lower than the LVEF at rest with same-day rest-stress and stress-rest imaging protocols. In the clinical setting, poststress LVEFs may be lower than true resting measurements, particularly in patients with moderate to severe stress-induced ischemia.