Clinical utility of prone imaging in patients with suspected respiration motion artifacts and claustrophobia

Objectives The objective of this study was to compare prone and supine imaging in patients with suspected respiratory motion artifact on attenuation corrected (AC) myocardial perfusion SPECT (MPS).

Methods Seventy pts referred for indicated MPS with Tc-99m perfusion tracers were evaluated with AC SPECT. Imaging was performed using standard parallel hole collimation with a Siemens Symbia T16 SPECT/CT. SPECT was performed over 180° contoured orbits at 3° increments for 15-20 sec per view into 128x128 matrices and 4.8 mm pixels in the prone and supine positions. Study time was 15-20 min and images were attenuation corrected using CT images acquired immediately before MPS. 28 pts were low likelihood normals and 14 pts had document coronary heart disease (CHD). Images including raw data cine and sinogram displays were review for respiratory and patient motion. Images were scored both respiratory and patient motion from 0 (no motion) to 4 (severe motion). Standard long and short axis displays were compared for quality, normalcy and correlation with angiography. Standard 17 segment scoring and blackout polarmap analyses were employed (Corridor4DM).

Results Assessment of raw data cine displays demonstrated significantly lower scores for prone images (0.8±1.0 prone as 1.5±1.2 supine, p<0.05). In normals the summed stress scores (SSS) were significantly lower with prone imaging (1.7±2.4 prone as 7.3±4.3 supine, p<0.01) and blackout defect sized were significantly lower (3.1±4.7 prone as 11.2±9.0 supine, p<0.01). Significantly more pts were normal imaged prone (39 prone as 14, p<0.001). In pts with documented CHD, SSS (6.8±7.1 prone as 5.6±4.7 supine, p=NS) and blackout analyses (14.0±15.3 prone as 9.8±8.7 supine, p=NS) were not significantly different. Eleven pts were able to tolerate only prone imaging due to claustrophobia.

Conclusions In patients with suspected respiratory motion artifacts and claustrophobia, prone imaging is a useful alternative to supine imaging demonstrating improved image quality and accuracy