ARRS 2022 Abstracts

RETURN TO ABSTRACT LISTING


1473. Comparison of Diagnostic Accuracy of MRI and Dual-Energy CT for Detection of Enhancement in Renal Masses
Authors * Denotes Presenting Author
  1. Trevor McGrath *; The Ottawa Hospital; University of Ottawa
  2. Faraz Ahmad; The Ottawa Hospital; University of Ottawa
  3. Paul Sathiadoss; The Ottawa Hospital; University of Ottawa
  4. Mohammad Haroon; The Ottawa Hospital; University of Ottawa
  5. Matthew McInnes; The Ottawa Hospital; University of Ottawa
  6. Patrick Bossuyt; Amsterdam University Medical Centers
  7. Nicola Schieda; The Ottawa Hospital; University of Ottawa
Objective:
The purpose of this study was to compare subjective and quantitative diagnostic accuracy of DECT and MRI for detection of enhancement in renal masses.

Materials and Methods:
We retrospectively searched our institutional Picture Archiving and Communications System (PACS) for consecutive patients who underwent rapid-kVp-switch renal protocol DECT between December 1, 2015 and June 1, 2020. Patients were eligible for inclusion if they had a renal mass of =10 mm, underwent renal protocol MRI within 12 months of DECT, and had an acceptable reference standard. Subjective enhancement (5-point scale Likert scale: definitely enhancing, likely enhancing, indeterminate, likely not-enhancing, definitely not enhancing) and quantitative enhancement (iodine concentration and attenuation or signal intensity [SI] ratio for DECT and MRI respectively) were evaluated for each mass independently by two fellowship-trained radiologists. Iodine concentration was = 1.2 mg/mL, attenuation change was = 20 HU, and SI was = 15% defined enhancement.

Results:
Twenty-four patients with 41 renal masses met inclusion criteria: 17 solid masses (six clear cell renal cell carcinoma [RCC], nine papillary RCC, one chromophobe RCC, and one oncocytoma) and 24 benign cysts (20 simple cysts and four hemorrhagic/proteinaceous cysts). Sensitivity and specificity of subjective enhancement on DECT using iodine overlay images was 94.1% (95% CI 71.3 – 99.9%) and 95.2% (95% CI 76.2 - 99.9%) respectively. Sensitivity and specificity of subjective enhancement on subtraction MRI was 94.1% (95% CI 71.3 – 99.9%) and 100% (95% CI 83.9 - 100%), respectively. Sensitivity and specificity of quantitative iodine concentration on DECT was 82.4% (95% CI 56.6 – 96.2%) and 95.2% (95% CI 76.2 - 99.9%) respectively. Sensitivity and specificity of attenuation measurements was 88.2% (95% CI 63.6 – 98.5%) and 100% (95% CI 83.9 - 100%), respectively. Sensitivity and specificity of SI-ratio was 88.2% (95% CI 63.6 – 98.5%) and 71.4% (95% CI 47.8 – 88.7%), respectively. Subjective enhancement assessment correctly identified 8/9 papillary RCC as enhancing for both DECT iodine overlay images and subtraction MRI. Quantitative iodine concentration on DECT correctly identified 6/9 papillary RCC as enhancing. Attenuation measurements and SI-ratio correctly identified 7/9 papillary RCC as enhancing.

Conclusion:
Subjective and quantitative diagnostic performance of DECT is similar to subtraction MRI for the detection of enhancement in renal masses, including a robust number of histologically confirmed low-enhancing papillary RCC.