Iodine-123 metaiodobenzylguanidine imaging and carbon-11 hydroxyephedrine positron emission tomography compared in patients with left ventricular dysfunction.
BACKGROUND
Although both (123)I-metaiodobenzylguanidine ((123)I-MIBG) imaging and (11)C-hydroxyephedrine ((11)C-HED) positron emission tomography (PET) are used for assessing cardiac sympathetic innervation, their relationship remains unknown. The aims were to determine whether (123)I-MIBG parameters such as heart-to-mediastinum ratio (H/M) are associated with quantitative measures by (11)C-HED PET and to compare image quality, defect size, and location between (123)I-MIBG single-photon emission computed tomography (SPECT) and (11)C-HED PET.


RESULTS
Twenty-one patients (mean left ventricular ejection fraction, 39 ± 15%) underwent (123)I-MIBG imaging and (11)C-HED PET. Early (15-minute), late (3-hour) H/M, and washout rate (WR) were calculated for (123)I-MIBG. Myocardial retention and WR was calculated for (11)C-HED. Using a polar map approach, defect was defined as the area with relative activity <60% of the maximum. Both the early (r=0.76) and late (r=0.84) (123)I-MIBG H/M were correlated with (11)C-HED retention. (123)I-MIBG WR was correlated with (11)C-HED WR (r=0.57). Defect size could not be measured in 3 patients because of poor quality (123)I-MIBG SPECT, whereas (11)C-HED defect was measurable in all patients. Although defect size measured by early or late (123)I-MIBG SPECT was closely correlated with that by (11)C-HED PET (early: r=0.94; late: r=0.88), the late (123)I-MIBG overestimated defect size particularly in the inferior and septal regions.


CONCLUSIONS
(123)I-MIBG H/M gives a reliable estimate of cardiac sympathetic innervation as measured by (11)C-HED PET. Furthermore, despite the close correlation in defect size, (11)C-HED PET appears to be more suitable for assessing regional abnormalities than does (123)I-MIBG SPECT.
Matsunari
Ichiro
I
The Medical and Pharmacological Research Center Foundation, Hakui, Japan. matsunari@mprcf.or.jp
Aoki
Hirofumi
H
Nomura
Yusuke
Y
Takeda
Nozomi
N
Chen
Wei-Ping
WP
Taki
Junichi
J
Nakajima
Kenichi
K
Nekolla
Stephan G
SG
Kinuya
Seigo
S
Kajinami
Kouji
K
D019797:3-Iodobenzylguanidine; D000368:Aged; D000369:Aged, 80 and over; D004809:Ephedrine / Q000031:analogs & derivatives*; D005260:Female; D006321:Heart / Q000294:innervation*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D049268:Positron-Emission Tomography; D011237:Predictive Value of Tests; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012189:Retrospective Studies; D013318:Stroke Volume; D013564:Sympathetic Nervous System / Q000000981:diagnostic imaging* / Q000503:physiopathology; D015899:Tomography, Emission-Computed, Single-Photon; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000503:physiopathology; D016277:Ventricular Function, Left
D019275:Radiopharmaceuticals; C065363:3-hydroxyephedrine; D019797:3-Iodobenzylguanidine; D004809:Ephedrine