Paul Douglas Evans MD, Presenter: Nothing to Disclose

Chad Michael Miller MD, Abstract Co-Author: Nothing to Disclose

Daniele Marin MD, Abstract Co-Author: Nothing to Disclose

Sandra Stinnett MS, MPH, Abstract Co-Author: Nothing to Disclose

Terence Zekon Wong MD, PhD, Abstract Co-Author: Nothing to Disclose

Lisa Mei-ling Ho MD, Abstract Co-Author: Nothing to Disclose

To determine diagnostic accuracy and inter-reader agreement of quantitative and qualitative methods in evaluation of adrenal nodules using CT/PET.

65 adrenal nodules (44 adenomas, 21 metastases) were retrospectively identified in 51 patients (31 men, 20 women, mean age 65, age range 45-84) with a history of lung cancer who underwent a CT/PET scan (Discovery ST, GE). Three readers with 1, 5, and 8 years of experience independently performed two quantitative measurements [SUVmax and SUVratio(adrenal nodule SUVmax/liver SUVavg)] and one qualitative assessment of each adrenal nodule (0 is adrenal nodule avidity<liver; 1 is avidity=liver; 2 is avidity>liver; 3 is avidity>>liver). Mean SUVmax and SUVratio of adrenal adenomas and metastases were determined for each reader. Accuracy, sensitivity, and specificity for detection of adenomas were calculated for each method by each reader using threshold values of ≤3.1 for SUVmax, ≤1.0 for SUVratio, and <2 for qualitative assessment. Intra-class correlation coefficient (ICC) and % agreement with kappa statistic were calculated for quantitative and qualitative methods.

Mean SUVmax of adenomas and metastases for readers 1, 2 and 3 were respectively 2.8±1.4 and 11.7±7.8; 2.6±1.3 and 11.0±7.3; and 2.7±1.4 and 10.5±7.7. For three readers, mean SUVratio of adenomas and metastases were 0.96±0.53 and 4.1±2.9; 0.92±0.61 and 3.7±2.7; 0.95±0.53 and 3.8±2.8. Mean sensitivity and specificity for SUVmax was 83% (range 79-89%) and 95% (range 86-100%). Mean sensitivity and specificity for SUVratio was 79% (range 73-86%) and 94% (range 86-100%). Mean sensitivity and specificity for qualitative assessment was 95% (range 93-98%) and 81% (range 71-86%). Mean diagnostic accuracy was 86% (range 81-92%), 85% (range 77-89%), and 91% (range 86-94%), for SUVmax, SUVratio, and qualitative assessment, respectively. ICC for quantitative measurements was 97-99% (95%CL 0.93-0.98). Percent agreement for qualitative assessment was 91-95% (95%CL 0.61-1.0) and kappa statistic was 0.78-0.89 (95%CL 0.61-1.0).

Both quantitative and qualitative methods demonstrate high diagnostic accuracy and excellent inter-reader agreement across all levels of reader experience.

Quantitative and qualitative methods are both accurate and reliable methods for distinguishing benign adenomas from metastases in patients with a known primary lung malignancy undergoing CT/PET.

Evans, P, Miller, C, Marin, D, Stinnett, S, Wong, T, Ho, L, CT/PET Characterization of Adrenal Nodules: Diagnostic Accuracy and Interreader Agreement Using Quantitative and Qualitative Methods.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11008553.html