Zhiyun Yang, Presenter: Nothing to Disclose

Mihran Naljayan BS, Abstract Co-Author: Nothing to Disclose

Horacio B. D'Agostino MD, Abstract Co-Author: Consultant, Oncura, Inc

Myocardial perfusion imaging (MPI) is a well-established method for evaluation of coronary artery disease (CAD). Soft tissue attenuation artifacts impair its accuracy. This study describes a simple strategy to differentiate MPI soft tissue attenuation artifacts from true perfusion defects.

The study includes 100 patients with MPI from October 2005-February 2006. Patient selection criteria included those with suspected CAD that had MPI and cardiac catheterization (CC) indicated for their evaluation. MPI was performed using thallium 201-chloride, 2.5-3.5 mCi for resting imaging; technetium-99m tetrofosmin, 20-30 mCi for stress imaging. Images were acquired on a GE DST.Xli gamma camera. Xeleris software was used for image processing. Studies were interpreted by a single nuclear medicine physician blinded regarding clinical and CC information. Sixteen parameters were used to interpret the study. CC findings were compared with MPI interpretation regarding which parameters were more reliable in diagnosing artifact defects vs. true lesions.

There were 127 MPI defects: coronary artery stenosis 70%, 49 defects. Combined use of four parameters (left ventricular volume [LVV], transient cavitary dilatation [TCD], margins, and severity of the defect) provided accuracy in distinguishing soft tissue attenuation artifact from true perfusion defect in 112 of the 127 MPI defects. Soft tissue artifacts can be distinguished using the following sequence: 1. LVV ≤ 80 ml associated to TCD ≥ 1.22= true perfusion defect (10 of 13 true defects). Of the 49 true defects, 13 defects have LVV ≤ 80 ml associated to TCD. 2. LVV > 80 ml regardless of TCD value, a fuzzy or irregular margin without marked severity= artifact (72 of 78 artifact defects).

In our experience artifacts were reliably differentiated from true perfusion defects by combining MPI parameter findings of left ventricular volume, TCD, margin, and severity of the lesion.

Soft tissue artifacts are present in up to 40% of MPI studies; therefore, this study is useful in making a diagnosis with efficiency, confidence, and accuracy.

Yang, Z, Naljayan, M, D'Agostino, H, Defect on Myocardial Perfusion Imaging: A Soft Tissue Artifact or a True Perfusion Defect? Practical Parameters to Improve Interpretation Accuracy.  Radiological Society of North America 2006 Scientific Assembly and Annual Meeting, November 26 - December 1, 2006 ,Chicago IL. http://archive.rsna.org/2006/4428880.html