Utility of a semi-quantification and automatic statistical analysis for the interpretation of brain perfusion SPECT in Alzheimer's disease

Introduction. - As the visual interpretation of the brain perfusion SPECT for the diagnosis of Alzheimer's disease might be difficult, it is wished to benefit from techniques allowing to improve the diagnostic accuracy especially for the inexperienced readers. Materials and methods. - Three readers retrospectively interpreted 77 Tc-99m-ECD SPECT studies within the context of suspected neurodegenerative disease. The probability of Alzheimer's disease was quoted from 1 to 5, and the optimum sensitivity and specificity values were determined from ROC curves. The readers also attributed a hypoperfusion score to 13 brain regions; a diagnosis was obtained from this semi-quantification using a simple logic rule. The SPECT scans were also analyzed using the Planet Neuro software and a diagnosis was reached from a threshold for 2 of the 90 analyzed regions. The gold standard was established by a comprehensive neurological evaluation with at least 5 years of follow-up. Results. - The sensitivities and specificities of the three readers were 50%, 56%, 28% and 76%, 83% and 90%, respectively. Using the semi-quantification they were 50%, 67%, 61% and 54%, 85%, 69%. The results of two readers were more in agreement. Using the automatic quantification, sensitivity was 78% and specificity 81%. Conclusion. - The semi-quantification seems to ameliorate the results of and the agreement between certain readers. However, the automatic quantification seems to be the only way of assisting all of the readers to improve their diagnostic performances. (C) 2014 Elsevier Masson SAS. All rights reserved.