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Congestive heart failure is a state of inadequate cardiac function under various etiologies. Cardiac imaging plays an important role for accurate detection of heart failure, assessment of severity of LV function, and precise analysis of tissue function in vivo. Recently, multislice CT(MSCT), magnetic resonance imaging (MRI), and positron emission tomography(PET) have been rapidly developed for clinical use for assessing patients with congestive heart failure. MSCT has been used for accurate assessment of LV function. Due to high spatial resolution, MSCT permits assessment of coronary stenosis without cardiac catheterization. MRI permits assessment of LV function and also tissue function. Particularly, infarcted myocardium is accurately delineated as an area of delayed enhancement by contrast enhancement MRI study. PET has been used for accurate assessment of myocardial viability based on the persistence of myocardial glucose metabolism. In addition, a various new PET tracers permit molecular and cellular function, such as neurotransmission and receptor function in vivo. These new imaging technique has a potential role for assessing risk stratification and providing appropriate treatment strategy.

Nuclear cardiology has played a significant role in the diagnosis and risk stratification of patients with coronary artery disease. MRI and multidector-row CT (MDCT) has recently been introduced in the field of clinical cardiology. For the management of patients with suspected coronary artery disease, it is important to understand the advantages and disadvantages of various imaging modalities. This review discusses the current roles and problems of these imaging modalities.

Iodine-123 beta-methyl iodophenylpentadecanoic acid (BMIPP) has been used for evaluating myocardial fatty acid metabolism in vivo. The whole body BMIPP imaging was acquired in 26 patients (11 with HCM, 11 with CAD and 4 with DCM) to calculate % uptake in the myocardium and to correlate its uptake with biochemical data, including blood sugar (BS), nonesterified fatty acid (NEFA) and insulin in the blood. BMIPP was administered at rest with overnight fasting state, and the anterior and posterior whole body imaging was performed one hour later. The background corrected whole myocardial counts were calculated to obtain %BMIPP uptake. In addition, the heart to mediastinum count ratio (H/M ratio) was calculated from the mean counts in the heart and the upper mediastinum in the anterior view. The %BMIPP uptake was 3.70 +/- 1.22% and H/M ratio was 2.30 +/- 0.23. The patients with DCM showed higher %BMIPP uptake values (DCM = 5.58 +/- 0.67% vs. CAD = 3.09 +/- 0.97% and HCM = 3.63 +/- 0.86%, both p < 0.01), but similar values of H/M ratio with other patients (DCM = 2.43 +/- 0.20, CAD = 2.22 +/- 0.25 and HCM = 2.32 +/- 0.20). Although the biochemical data varied at the time of the tracer administration, they were not significantly correlated with the %BMIPP uptake or H/M ratio. However, there was a significant correlation between %BMIPP uptake and H/M ratio with the correlation coefficient of 0.80 (p < 0.001). We conclude that the myocardial uptake of BMIPP is not influenced by the plasma substrate level under the fasting state.

Quantitative assessment of myocardial tracer uptake in stress-delayed thallium and resting BMIPP imagings were performed in 24 patients with coronary artery disease. Each distribution was displayed on the bull's eye polar map and % uptake of each distribution was calculated as a mean value in 9 myocardial segments on the polar map. Redistribution index (% delayed uptake minus % stress uptake on thallium images) and discordance index (% delayed thallium uptake minus % BMIPP uptake) were also calculated. Each parameter was compared to the visual uptake score and wall motion score on contract left ventriculography. Excellent correlations were obtained between % uptake and the uptake score in each tracer. The % thallium and BMIPP uptake also correlated with regional wall motion score. Furthermore, a significant correlation was observed between redistribution and discordance indexes in the mildly hypoperfused segments. These data indicate that the quantitative analysis of thallium and BMIPP distributions seems to be valuable to understand relationship between perfusion and regional wall motion. The discordant BMIPP uptake may represent asynergic but viable segments. However, several important factors, such as attenuation factor should be also taken into consideration for such quantitative analysis.

Recent studies suggested the potential use of 123I-N-isopropyl-p-iodoamphetamine (IMP) for the assessment of pathophysiology of epilepsy. We studied a case of epilepsy with increased accumulation of IMP. Brain SPECT scan of IMP was performed in a case of 31-year-old male with traumatic epilepsy. Increased accumulation of IMP was observed in the left temporal area on both early (20 min after injection) and delayed (3 hr) images of studied 6 weeks after the head trauma. X-CT did not show any abnormalities. The accumulation of IMP decreased as the symptom of the patient improved. The SPECT study performed 3 months after the accident showed slightly decreased uptake in the left temporal area on the early image with homogeneous uptake in the delayed image. These findings suggested the altered retention mechanism of IMP in this case.