Masao Miyagawa MD, PhD, Presenter: Nothing to Disclose

Yoshiko Nishiyama MD, Abstract Co-Author: Nothing to Disclose

Rami Yokoyama, Abstract Co-Author: Nothing to Disclose

Kana Sakamoto Ide, Abstract Co-Author: Nothing to Disclose

Takuya Matsuda, Abstract Co-Author: Nothing to Disclose

Masashi Nakamura, Abstract Co-Author: Nothing to Disclose

Yuki Tanabe, Abstract Co-Author: Nothing to Disclose

Teruhito Mochizuki MD, Abstract Co-Author: Nothing to Disclose

I-123 Metaiodobenzylguanidine (MIBG) has been used to assess sympathetic nerve activity, but most studies have used planar imaging to measure heart-to-mediastinum ratiio (H/M). Cardiac cadmium-zinc-telluride (CZT) SPECT is inherently tomographic imaging, so it is incapable of chest planar imaging. The aim of the study is to obtain the H/M by utilizing CZT SPECT and validate the utility of it in comparison with H/M measured by planar imaging with Anger camera in the same patient (pt). 

Seventy-one consecutive pts with suspected Parkinson' disease (36 males; 69±11 y) were included. Ten min after injection of 111 MBq MIBG, early planar imaging with 8 min was performed first on a dual-head Anger camera equipped with an extended LEGP collimator, immediately followed by CZT SPECT (DNM 530c; GE Healthcare) with 20 min. Delayed imaging was performed in the same manner 5 hrs after injection. Early and delayed H/M on the planar images were analyzed with the conventional region-of interest (ROI) technique. For the CZT SPECT, transaxial images with 4 mm thickness were reconstructed, then 40 coronal images were stacked using a Volumetrix softwere. On the summed coronal images, the heart ROI was manually drawn and the 3x5 pixels of the mediastinum ROI was set. H/M was calculated by dividing the mean counts in the heart voxel-of-interest (VOI) divided by the mean counts in the mediastinum VOI. Same VOIs were semi-automatically set on the delayed coronal images.  

The intra- and inter-observer correlation coefficients were 0.93 and 0.89 for early H/M, and 0.91 and 0.89 for delayed H/M, respectively. Early H/Ms obtained from the planar imaging was 2.23±0.58, which was significantly higher than those of CZT SPECT (2.0±0.83, P<0.0001). There was a good correlation between them (Y=1.26X - 0.82, R2=0.78, P<0.0001). Delayed H/Ms obtained from the planar imaging was 2.17±0.93, which was significantly higher than those of CZT SPECT (1.71±0.97, P<0.0001). An excellent correlation was found between them (Y=0.989X - 0.44, R2=0.89, P<0.0001).

H/M measured on the summed coronal image of the CZT SPECT with MIBG had an excellent correlation with that from the planar imaging with conventional Anger camera. Thus, it may become an acceptable alternative to the planar H/M.

Measurement of H/M utilizing CZT SPECT with MIBG is feasible nd reliable. It may become an acceptable alternative to the planar H/M.

Miyagawa, M, Nishiyama, Y, Yokoyama, R, Ide, K, Matsuda, T, Nakamura, M, Tanabe, Y, Mochizuki, T, Heart-to Mediastinum Ratio Measured from I-123 MIBG SPECT with CZT Camera: Direct Comparison with the Planar Imaging.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14017730.html