Abstract
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Objectives To compare and assess the utility of different diagnostic modalities including CECT, MIBG whole body imaging with SPECT-CT and 68GaDOTANOC PET-CT for diagnosis of patients suspicion with pheochromocytoma.
Methods We prospectively evaluated the data of 31 patients (Age: 34.35±20.26 years; male/female:18/13) with symptomatically and biochemically suspicious for pheochromocytoma, who underwent abdomino-pelvic CECT, MIBG whole body with SPECT-CT and 68GaDOTANOC PET-CT from August 2010 to December 2014 All 31 patients have definitive anatomical lesion in CECT images. MIBGandPET-CT images were reviewed by two nuclear medicine physicians who were blinded to all details except for primary diagnosis. Clinical and imaging follow-up (minimum- 12 months) with histopathology (when available) were taken as reference standard.
Results Out of the 31 patients, 15 patients were truly positive for primary disease. Of which11 patients were localized for the primary disease in adrenal and remaining in extra- adrenal locations, which was urinary bladder. Of the 31 MIBG imaging, twelve were true positive, 16 were true negative, none was false positive and 3 were false negative. While in 68Ga DOTANOC PET-CT, eleven were true positive, 15 were true negative, one was false positive and 4 were false negative. The overall sensitivity, specificity, PPV, NPV and accuracy of MIBG were 80% [95% CI: 92-96], 100% [95% CI: 79-100], 100% [95% CI: 73-100], 84% [95% CI: 60-96%] and 80% respectively. Comparatively, sensitivity, specificity, PPV, NPV and accuracy of 68Ga DOTANOC PET-CT were 92% [95% CI: 61-99], 79% [95% CI: 54-94], 73% [95% CI: 45-92], 94% [95% CI: 70-99%] and 73% respectively. Of 15 positive patients, 68Ga DOTANOC PET-CT changed the management by additionally identified metastatic disease in 2 patients (distant lymph node and skeletal metastasis each patient).
Conclusions 68Ga-FDG PET-CT and MIBG appears to be highly specific for diagnosis of patients with pheochromocytoma and couplementry for this purpose.