Regional wall thickening in gated myocardial perfusion SPECT in a Japanese population: effect of sex, radiotracer, rotation angles and frame rates.
OBJECTIVE
Gated single-photon emission computed tomography (SPECT) imaging of myocardium by (99m)Tc and (201)Tl is used extensively to measure quantitative cardiac functional parameters. However, factors affecting normal values for myocardial functional parameters and population-specific standards have not yet been established. The aim of the study was to determine the effect of sex, radiotracer, rotation angles and frame rates on resting myocardial wall thickening (WT) and to develop a Japanese standard of normal values for WT.


METHODS
Data from a total of 202 patients with low possibility of having cardiac problems were collected from nine hospitals throughout Japan. Patients were divided into five groups according to study protocol, and WT was evaluated according to the 17-segment and four-region (basal, mid and apical regions and the apex) polar map distribution.


RESULTS
WT was generally higher in women than in men irrespective of the use of radiotracers, rotation angles or frame rates, and the difference was highly significant in the mid and apical regions. In any protocol used, resting myocardial thickening in the apex was higher than in the mid and apical regions, and thickening was lowest in the basal region, suggesting heterogeneous regional myocardial thickening (%) in normal subjects. Different rotation angles showed no significant change on WT, but different frame rates and tracers showed significant WT change in both sexes. Percent thickening of the myocardium was significantly higher in imaging by (99m)Tc-labelled tracers than in (201)Tl.


CONCLUSIONS
Sex, radiotracers and frame rates had a significant effect on myocardial thickening, and the importance of population-specific standards should be emphasized. A normal database can serve as a standard for gated SPECT evaluation of myocardial thickening in a Japanese population and might be applicable to Asian populations having a similar physique.
Akhter
Nasima
N
Department of Nuclear Medicine, Kanazawa University Hospital, 13-1 Takara-machi, Kanazawa, Ishikawa, Japan.
Nakajima
Kenichi
K
Okuda
Koichi
K
Matsuo
Shinro
S
Yoneyama
Tatsuya
T
Taki
Junichi
J
Kinuya
Seigo
S
D000368:Aged; D016477:Artifacts; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging* / Q000502:physiology*; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D011868:Radioisotopes; D012016:Reference Values; D012399:Rotation; D012727:Sex Characteristics; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*
D011868:Radioisotopes