Exp Clin Endocrinol Diabetes 2013; 121 - P28
DOI: 10.1055/s-0033-1336698

Functional characterisation of adrenal lesions using [123I]IMTO-SPECT/CT

S Hahner 1, MC Kreissl 2, M Fassnacht 3, H Hänscheid 4, S Bock 1, FA Verburg 5, P Knödler 6, K Lang 1, C Reiners 4, AK Buck 4, B Allolio 1, A Schirbel 4
  • 1Universitätsklinik Würzburg, Endocrinology and Diabetology, Würzburg, Germany
  • 2Klinikum Augsburg, Nuclear Medicine, Augsburg, Germany
  • 3Universitätsklinik München, Klinikum Innenstadt, Endocrinology and Diabetology, München, Germany
  • 4Universitätsklinik Würzburg, Nuclear Medicine, Würzburg, Germany
  • 5Universitätsklinik Aachen, Nuclear medicine, Aachen, Germany
  • 6Universitätsklinik Würzburg, Radiology, Würzburg, Germany

Aims: Adrenal tumors are highly prevalent and represent a wide range of different pathological entities. Conventional imaging often provides only limited information on the origin of these lesions. Novel specific imaging methods are, therefore, of great clinical interest. We have recently developed [123I]iodometomidate ([123I]IMTO) as a new radiotracer for specific molecular imaging of CYP11B1/2 enzymes.

Objective: Evaluation of the clinical utility of [123I]iodometomidate ([123I]IMTO) imaging for non-invasive characterization of adrenal masses

Methods: 51 patients with an adrenal lesion underwent [123I]IMTO imaging after injection of 185 MBq [123I]IMTO. Sequential planar whole body scans until 24 hours p.i. and SPECT/CT imaging 4 – 6h p.i. were performed.

Results: Adrenocortical tissue showed high and specific tracer uptake with short investigation time and low radiation exposure. Qualitative analysis of SPECT/CT data resulted in a sensitivity of 89% and a specificity of 85% for differentiating adrenocortical tumors from lesions of non-adrenocortical origin. ROC analysis of semiquantitative data revealed a sensitivity of 83% and a specificity of 86% for identification of adrenocortical lesions at a cut-off value of tumor- to-liver ratio of 1.3.

Conclusions: [123I]IMTO is a highly specific radiotracer for imaging of adrenocortical tissue with short investigation time and low radiation exposure. Due to the general availability of SPECT technology, [123I]IMTO scintigraphy has the potential to become a widely used tool to non-invasively characterize the biology of adrenal lesions.