The utility of PET/CT with 68Ga-DOTATOC in sarcoidosis: comparison with 67Ga-scintigraphy

Objective

This study was designed to compare the clinical efficacy of ⁶⁸Ga-DOTA-Tyr-octreotide (DOTATOC)-positron emission tomography (PET)/computed tomography (CT) with that of conventional ⁶⁷Ga-scintigraphy (GS), and to correlate quantitative parameters on DOTATOC-PET/CT with clinical data, in patients with sarcoidosis.

Methods

Twenty patients who were histologically and/or clinically diagnosed with sarcoidosis and underwent both DOTATOC-PET/CT and GS were analyzed in this study. The numbers of patients with positive findings for each organ were determined. The total numbers of involved nodal areas in the chest, as determined by DOTATOC-PET and gallium single-photon emission tomography (Ga-SPECT), were compared. The correlations between quantitative parameters on PET and clinical laboratory data were evaluated.

Results

DOTATOC-PET/CT was positive in 19 patients, being negative in only one patient with chronic inactive sarcoidosis, whereas GS was positive in 17 patients. DOTATOC-PET/CT visualized more lesions in lymph nodes, uvea, and muscles than did Ga-scintigraphy and identified more involved areas than did GS-SPECT (p < 0.0001). Whole-body active lesion volume showed a significant, but moderate correlation with angiotensin-converting enzyme level (ρ = 0.64, p = 0.0044).

Conclusions

PET/CT with DOTATOC may be superior to conventional GS in detecting sarcoidosis lesions, especially in lymph nodes, uvea, and muscles. Volumetric parameters in DOTATOC-PET/CT may be helpful in estimating the activity of sarcoidosis.