Erschienen in:
01.02.2011 | Original Article
Semi-automated algorithm for calculating heart-to-mediastinum ratio in cardiac Iodine-123 MIBG imaging
verfasst von:
Koichi Okuda, MS, Kenichi Nakajima, MD, Tetsuo Hosoya, Takehiro Ishikawa, MS, Takahiro Konishi, NMT, Kosuke Matsubara, PhD, Shinro Matsuo, MD, Seigo Kinuya, MD
Erschienen in:
Journal of Nuclear Cardiology
|
Ausgabe 1/2011
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Abstract
Background
We have developed novel software for semi-automatically measuring heart-to-mediastinum (H/M) ratio in cardiac Iodine-123 (123I)-labeled meta-iodobenzylguanidine (MIBG) imaging. Our aim is to improve the reproducibility of the H/M ratio using the semi-automated method as opposed to the manual method.
Methods and Results
The software algorithm automatically determined the mediastinal region of interest (ROI) using information from 123I-MIBG uptake of the heart, lung, liver, and thyroid after a cardiac circular ROI was manually set. A total of 37 patients who underwent both early and delayed 123I-MIBG imaging was retrospectively selected. The heart-to-mediastinum (H/M) ratios were calculated by both semi-automated and manual methods and assessed for the intra- and inter-observer variability. All H/M ratios were classified into three groups: normal, slight abnormality, and severe abnormality. The H/M ratios with the new method were higher than those obtained manually (P<.001). In the test-retest reliability, the intra-class correlation coefficient from the semi-automated method showed excellent reproducibility for early (0.99) and delayed (0.99) imaging. The Bland-Altman plots demonstrated better agreement using the semi-automated method (a range of 95% limits −0.11 to 0.10) than that in the manual method (−0.34 to 0.27). The inter-observer agreement was also good using the semi-automated method (κ = 0.866).
Conclusions
The H/M ratio using the semi-automated method showed high reproducibility in both early and delayed imaging.