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Takamura T, Horiguchi Y, Kanna M, Matsushita H, Sudo Y, Kikuchi S, Ueda T, Sasaki R, Morita Y. Validation of prone myocardial perfusion SPECT with a variable-focus collimator versus supine myocardial perfusion SPECT with or without computed tomography-derived attenuation correction. Ann Nucl Med 2015; 29:890-6. [PMID: 26307758 DOI: 10.1007/s12149-015-1019-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Accepted: 08/12/2015] [Indexed: 02/01/2023]
Abstract
OBJECTIVE The purpose of this study is to evaluate whether prone myocardial perfusion single-photon emission computed tomography (MPS) with thallium-201 acquired through a variable-focus collimator (IQ-SPECT) can correct for soft-tissue attenuation. METHODS Thirty-nine patients underwent thallium-201 stress MPS with IQ-SPECT. Delayed images acquired with the patients in the prone position were compared with delayed images obtained with the patients in the supine position with computed tomography-derived attenuation correction (CTAC) (S-CTAC images) or without CTAC (S-NCTAC images). Quantitative tracer uptake (QTU) and semi-quantitative defect scores were determined for the 17 standard myocardial segments. Segments were categorized into anterior-anteroseptal, lateral, inferior, and apex, and areas with defect decision were determined by using the defect scores. RESULTS Image quality in the prone images was similar to that of S-NCTAC and S-CTAC images. In male patients, QTU in prone images was equivalent to that in S-CTAC images in the anterior-anteroseptal area, but was significantly lower than that in S-CTAC images in the inferior area. In female patients, QTU in prone images was similar to that in S-CTAC images in the anterior-anteroseptal, lateral, and inferior areas. In male and in female patients, QTU in the apex was significantly greater in the prone images than that in the S-CTAC images. In the combined male and female patient group, the defect decision for prone images was similar to that for S-CTAC images in the anterior-anteroseptal, lateral, and inferior areas. Apical defects were observed more frequently in S-CTAC images than in prone or S-NCTAC images. CONCLUSIONS Fewer artificial defects were observed in the apex of images acquired by prone imaging than by S-CTAC imaging. Prone images improved attenuation and had similar defect decision as S-CTAC images in the anterior-anteroseptal, lateral, and inferior areas.
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Affiliation(s)
- Tomoko Takamura
- Department of Cardiology, National Hospital Organization Sagamihara National Hospital, 18-1 Sakuradai, Minami-ku, Sagamihara City, Kanagawa, 252-0392, Japan
| | - Yoriko Horiguchi
- Department of Cardiology, National Hospital Organization Sagamihara National Hospital, 18-1 Sakuradai, Minami-ku, Sagamihara City, Kanagawa, 252-0392, Japan.
| | - Masahiko Kanna
- Department of Cardiology, National Hospital Organization Sagamihara National Hospital, 18-1 Sakuradai, Minami-ku, Sagamihara City, Kanagawa, 252-0392, Japan
| | - Hirooki Matsushita
- Department of Cardiology, National Hospital Organization Sagamihara National Hospital, 18-1 Sakuradai, Minami-ku, Sagamihara City, Kanagawa, 252-0392, Japan
| | - Yuta Sudo
- Department of Cardiology, National Hospital Organization Sagamihara National Hospital, 18-1 Sakuradai, Minami-ku, Sagamihara City, Kanagawa, 252-0392, Japan
| | - Shinnosuke Kikuchi
- Department of Cardiology, National Hospital Organization Sagamihara National Hospital, 18-1 Sakuradai, Minami-ku, Sagamihara City, Kanagawa, 252-0392, Japan
| | - Tomohiro Ueda
- Department of Radiology, National Hospital Organization Sagamihara National Hospital, Kanagawa, Japan
| | - Ryo Sasaki
- Department of Radiology, National Hospital Organization Sagamihara National Hospital, Kanagawa, Japan
| | - Yukiko Morita
- Department of Cardiology, National Hospital Organization Sagamihara National Hospital, 18-1 Sakuradai, Minami-ku, Sagamihara City, Kanagawa, 252-0392, Japan
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Abstract
OBJECTIVES Decreases in apical and apex activities - namely, 'apical thinning' - are a well-known phenomenon in attenuation-corrected (AC) myocardial perfusion. The aim of this study was to compare actual myocardial thickness derived from a multidetector-row computed tomography with AC myocardial perfusion count from a hybrid single-photon emission computed tomography/computed tomography to investigate the cause of apical thinning. METHODS We enrolled 21 participants with a low likelihood of coronary artery disease (mean age 65 ± 21 years, 13 men) from 185 consecutive patients and 11 healthy volunteers, who independently underwent ⁹⁹mTc-sestamibi single-photon emission computed tomography/computed tomography and 64-slice multidetector-row computed tomography scans. AC and non-AC myocardial perfusion counts and thickness were measured on the basis of a 17-segment model and averaged at the apex, apical, mid, and basal walls. RESULTS Myocardial thickness at the apex was significantly thinner than that at the apical and mid walls (5.1 ± 1.3, 7.3 ± 1.3, and 9.9 ± 2.4 mm, respectively; P<0.005). AC count at the apex was significantly lower than that at the apical and mid regions (76.0 ± 5.5, 82.8 ± 4.7, and 85.6 ± 3.8, respectively; P<0.002). Moderate relationship was observed between myocardial thickness and AC count (y=-10.5 + 0.22x, r=0.54, P<0.0001. No relationship was found between thickness and non-AC count (r=0.16, P=0.263). CONCLUSION The low apex and apical counts were caused by anatomical thinning of the myocardium in AC myocardial perfusion imaging. Attenuation correction provided an accurate relationship between myocardial count and thickness because of the partial volume effect.
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