Acne Scars

Nucl Med Commun. 2009 May 30; Liu Q, Zhao S, Yan C, Lu M, Jiang S, Zhang Y, Li S, Liu Y, Yang M, He ZOBJECTIVES: We sought to compare delayed-enhancement MRI (DE-MRI) with Tc-sestamibi and F-fluorodeoxyglucose (F-FDG) single-photon emission computed tomography (SPECT) for the assessment of myocardial viability. METHODS: Thirty-four patients with prior myocardial infarction underwent DE-MRI and Tc-sestamibi/F-FDG SPECT. The area of delayed enhancement by DE-MRI was defined as scar tissue. The region with concordantly reduced perfusion and glucose metabolism was defined as nonviable myocardium. In a 17-segment model, the segmental extent of hyperenhancement was compared with segmental Tc-sestamibi and F-FDG uptake defect. All segments were divided into five different severities by segmental extent of hyperenhancement in DE-MRI and were classified into different viability situations by segmental Tc-sestamibi and F-FDG uptake in SPECT. RESULTS: A total of 578 segments were studied. Sensitivity and specificity of DE-MRI in identifying segments with flow/metabolism match were 61.32 and 95.35%, respectively. Semiquantitatively assessed relative MRI scar tissue correlated well with Tc-sestamibi and F-FDG SPECT (r = 0.63, P = 0.0284). However, of the 431 segments defined as normal by DE-MRI, 82 segments (19%) were scored as nonviable by F-FDG SPECT. During these segments, 48 showed less than 50% reduced F-FDG uptake, 25 showed 50-75% reduced F-FDG uptake, and nine showed no F-FDG uptake. CONCLUSION: MRI hyperenhancement as a marker of myocardial scar closely agrees with Tc-sestamibi and F-FDG SPECT. Nuclear technology and DE-MRI show their own predominance and limitation in assessment of myocardial viability and detecting irreversibly injured tissue.