Impact diagnostique de la TEMP–TDM dans l’exploration des tumeurs endocrines

Abstract

Image fusion using single photon emission computed tomography–computed tomography (SPECT–CT) associates functional and morphological images. This study evaluates the added value of SPECT–CT, obtained with a hybrid SPECT–CT gamma camera, on anatomic localization and diagnostic impact in assessment of endocrine tumours and pheochromocytomas. Method Six months prospective study was undertaken including 33 consecutive exams encompassing 20 Somatostatin Receptor Scintigraphies (SRS) and 13 123I-meta-iodo-benzyl-guanidine (MIBG) scans. Two experienced nuclear medicine physicians independently analysed independently planar and SPECT images in a first time, then, SPECT–CT fused images in a second time. They evaluated two parameters: SPECT–CT impact on anatomic localization (LA) and its diagnostic impact (ID). Each parameter was scored according three levels of evaluation. Results An added value of SPECT–CT images was evidenced in 55% of cases on the anatomic localization and in 41% of the patients on the diagnostic impact. Therefore, a more important benefit was noted when SPECT was positive (LA: 90%; ID: 70%) than when it was negative (LA: 15%; ID: 8%). Furthermore, the added value proved higher for the SRS compared to MIBG scans. Conclusion SPECT–CT fusion images obtained by a hybrid system is more relevant to determine anatomic localization and more accurate than SPECT alone, particularly in the assessment of endocrine tumours. The added value of SPECT–CT seems to be lower for MIBG scans in the assessment of pheochromocytomas.