03:54 PM Abstract No. 128 Accuracy of diagnostic ultrasound, CT, and MRI compared with volumetric cone-beam CT measurement in predicting hyperplastic prostate gland volume

Abstract

To evaluate accuracy of hyperplastic prostate gland volume measurement by ellipsoid volume calculation using ultrasound, CT or MRI images, compared to volumetric measurement made with cone-beam CT. 142 patients who underwent PAE from May 2013 through August 2018 were retrospectively reviewed. All available preprocedural transabdominal ultrasound (US), CT, and MRI studies or reports were reviewed and estimated prostate gland volumes (PGV) using ellipsoid volume calculation (V=4/3*πabc) were recorded. During each PAE case, axial pelvic cone-beam CT (CBCT) images were acquired with coronal and sagittal images reconstructed. PGVs were re-measured with these images, both using ellipsoid volume calculation (CBCT-E) and slice-by-slice three dimensional volumetric measurement (CBCT-V). Patients were excluded if preprocedural or procedural measurements were unavailable. Comparisons were made using paired Student T-tests. 63 patients had preprocedural transabdominal ultrasound PGV measurements with mean PGV of 122.5mL, compared to corresponding CBCT-E mean PGV of 140.0mL and CBCT-V mean PGV of 161.9mL obtained during PAE. 32 patients had pelvic CT gland volume measurements with mean PGV of 225.2mL, compared to their corresponding CBCT-E mean PGV of 223.0mL and CBCT-V mean PGV of 254.8mL obtained during PAE. 13 patients had preprocedural pelvic MRI gland volume measurements, with mean PGV of 152.6mL, compared to corresponding CBCT-E mean PGV of 192.3mL and CBCT-V mean PGV of 214.6mL obtained during PAE. 27 patients had no prior imaging available, but had CBCT-E mean PGV of 119.2mL and CBCT-V mean PGV of 153.9mL obtained during PAE. When compared to CBCT-V, ultrasound underestimated PGV by 24% (P<0.0001), CT underestimated PGV by 12% (P<0.01), CBCT-E underestimated PGV by 14% (P<0.0001), and MRI underestimated PGV by 29% (P<0.0001). Diagnostic imaging modalities, particularly ultrasound, significantly underestimated PGV in this study. Correction factors may better calibrate assessment of PGV and thereby further truncate appropriate procedural treatment options for symptomatic prostatic hyperplasia. Importantly, PAE has been shown to be effective regardless of gland size1.