Parametric polar maps of regional myocardial beta-adrenoceptor density

Citation
Rm. De Jong et al., Parametric polar maps of regional myocardial beta-adrenoceptor density, J NUCL MED, 40(4), 1999, pp. 507-512
Citations number
31
Categorie Soggetti
Radiology ,Nuclear Medicine & Imaging","Medical Research Diagnosis & Treatment
Journal title
JOURNAL OF NUCLEAR MEDICINE
ISSN journal
01615505 → ACNP
Volume
40
Issue
4
Year of publication
1999
Pages
507 - 512
Database
ISI
SICI code
0161-5505(199904)40:4<507:PPMORM>2.0.ZU;2-7
Abstract
Quantification of myocardial beta-adrenoceptor density (B-max) is of intere st in cardiac diseases in which altered function of the sympathetic nervous system is thought to play a pathophysiological role. PET provides an unriv aled means of taking regional measurements of cardiac microcirculatory func tion, tissue metabolism and autonomic nervous system activity. Measurements in small regional areas may be biased because of increased noise levels. T his study examined the parametric polar map approach for the regional quant ification of B-max. Methods: Dynamic PE-T with parametric polar map imaging was performed in 10 healthy volunteers and 4 patients with hypertrophic ca rdiomyopathy using (S)-[C-11]-(4-(3-tertiarybutylamino-2-hydroxypropoxy)-be nzidimazole-2)-on hydrochloride (CGP)-12177 and a double-injection protocol . Time-activity curves were corrected for partial volume, spill-over and wa ll motion effects. The mean B-max of the left ventricle was calculated in t wo ways. First, the average time-activity curve of all segments, having the highest achievable signal-to-noise ratio, was used to calculate B-max(mTAC ) (the myocardial beta-adrenoceptor density of the left ventricle calculate d using the average time-activity curve). The bias in B-max(mTAC) introduce d by noise is minimal. Second, an estimate of whole-heart receptor density was calculated using the polar map method by averaging the values of B-max obtained for 576 individual segments. In these calculations, three differen t filters (3 x 5, 3 x 9 and 3 x 13 segments) were used to smooth the time-a ctivity curves before calculating B-max. Mean values of whole-left-ventricu lar receptor density obtained by averaging regional values using the differ ent filters (B-max(PMF1/2/3)) were compared with B-max(mTAC) to assess bias introduced by the polar map approach. Segments with a calculated B-max out side the range 0.1-50 pmol/g were considered unreliable and were excluded f rom the analysis. Results: The differences between the two methods of calcu lating B-max were small (7.8%, 4.8% and 3.2%, with the three filters, respe ctively). Reliable results were obtained in >95% of the segments and in 9 v olunteers and all 4 patients. Conclusion: When using PET for the quantifica tion of beta-adrenoceptor density, the regional variation in B-max can be r eliably assessed using the parametric polar map approach.