RT Journal Article SR Electronic T1 Assessment of Clinical Impact in the Application of Chang Attenuation Correction to Lung Ventilation/Perfusion SPECT JF Journal of Nuclear Medicine Technology JO J. Nucl. Med. Technol. FD Society of Nuclear Medicine SP 290 OP 294 DO 10.2967/jnmt.110.086470 VO 39 IS 4 A1 Sina Izadyar A1 Sassan Saber A1 Ali Gholamrezanezhad YR 2011 UL http://tech.snmjournals.org/content/39/4/290.abstract AB The presence of a highly nonuniform distribution of attenuating tissues in the thorax may lead to attenuation artifacts and inaccuracies in reconstructed lung ventilation/perfusion SPECT images. The Chang algorithm is an easily applicable and accessible method of attenuation correction. The advantages inherent in the technique prompted us to evaluate the effect of using Chang attenuation correction on the quality of lung SPECT images and the clinical impact on interpretation. Methods: Lung scintigraphy started with planar and SPECT ventilation scans using 81mKr. A few minutes after the ventilation scintigraphy, planar and SPECT perfusion studies using 99mTc-macroaggregated albumin were performed. The Chang algorithm was applied for attenuation correction. Afterward, standard SPECT processing was performed on the images, leading to images in the horizontal, coronal, and sagittal planes. The same studies were also processed to the same planes without application of attenuation correction. Finally, all scintigraphic images were reviewed by 2 nuclear medicine academic clinicians, and a final diagnosis was reached by consensus, categorizing the studies into 3 groups—normal, low/intermediate, and high probability—for pulmonary embolism. Results: The study included 45 patients (16 men and 29 women) with a mean age of 50.0 y. Between the 2 noncorrected and attenuation-corrected readings, 16 diagnoses remained the same. However, after attenuation correction, 13 patients were moved to lower categories (i.e., from high probability to normal or low/intermediate probability or from low/intermediate probability to normal) and 16 patients were moved to higher categories (i.e., from low/intermediate probability to high probability or from normal to low/intermediate or high probability). The difference between noncorrected and attenuation-corrected readings was statistically significant (P < 0.01). Conclusion: After attenuation correction, subjective image quality and sharpness improved, leading in some cases to increased confidence on the part of the readers. The Chang attenuation correction method may have the potential to be considered as an alternative approach toward attenuation correction in those situations in which the additional radiation burden of CT is not acceptable.