Apical thinning: real or artefact?

• DOI: 10.1097/mnm.0b013e3282f4a22e
• Publication Date: 2009-03-05T15:16:50Z
• Authors: Nicola J. Purser; Ian S. Armstrong; Heather A. Williams; Christine M. Tonge; Richard S. Lawson
• Keywords: Correction for attenuation; Apex (geometry); Thinning; Torso

Apical thinning is a well-known phenomenon in myocardial perfusion SPECT, often attributed to reduced thickness at the apex of left ventricle. Attenuation correction processing appears exaggerate this effect. Although currently there agreement that apical counts are not diagnostic indicator, opinions differ over cause effect; we sought clarify using results from phantom study.A commercially available anthropomorphic torso was expanded attachments mimicking tissue and bone create three phantoms increasing size. These were imaged dual-headed gamma camera low-dose CT-based attenuation correction. The data processed iterative reconstruction, with without correction.The cardiac insert had uniform wall yet defects characteristic appeared after correction, severity Before flare activity seen corresponding position size defect Further investigations showed following: depth-dependent resolution responsible; more noticeably dependent on addition breast than attenuating material; artefact unique one particular algorithm; number iterations artefact.Data acquisition methods thought be responsible for apparent defect. This study therefore demonstrates simply an anatomical feature but can also introduced by use