Dr Randall on the Diagnostic Accuracy and Cost Effectiveness of MRI vs Ultrasound in STS

“In terms of diagnostic performance, [MRI and ultrasound] had similar accuracy.”

R. Lor Randall, MD, FACS, the David Linn Endowed Chair for Orthopedic Surgery, the chair of the Department of Orthopedic Surgery, and a professor at the University of California Davis Comprehensive Cancer Center, discussed findings from a comparison of the diagnostic accuracy, recurrence detection rates, cost effectiveness, and outcomes with MRI vs ultrasound disease surveillance in patients with soft tissue sarcoma of the extremity.

The study employed a PRISMA Scoping Review methodology, using databases such as PubMed, Embase, and Scopus for source identification, Randall began. The search range used for Scopus encompassed the years 1990 to 2025. Inclusion criteria dictated that only post-resection surveillance studies that used ultrasound, MRI, or both imaging modalities were included in the final analysis.

A large initial search yielded 366 potential studies; however, only 8 ultimately met the stringent criteria for inclusion in the review. The limited cohort of relevant literature was composed of 2 prospective studies, 4 retrospective studies, and 2 review papers. Across the 8 identified studies, the investigation encompassed data from 856 patients.

Regarding diagnostic performance, the review indicated that both MRI and ultrasound exhibited similar overall accuracy. The reported range for MRI sensitivity was 83% to 100%, coupled with a specificity rate range of 92.9% to 98.5%. The sensitivity rates with ultrasound were slightly lower, ranging from 75% to 100%, though the specificity rate range of this modality was comparable with that of MRI, spanning 79% to 97.6%. The analysis revealed that there was no statistically significant difference in diagnostic capability between the 2 modalities across the combined studies. Furthermore, the review highlighted the efficacy of hybrid protocols, noting that when both MRI and ultrasound were used in conjunction, 100% recurrence detection was achieved, compared with 65% detection when relying on MRI alone.

Data concerning the cost effectiveness of these imaging strategies are currently limited, according to Randall. However, he reported that previously published research has shown a large economic difference between the 2 modalities, with ultrasound shown to be less costly than MRI.

Regarding clinical outcomes, the identified local recurrence rates varied substantially across the studies, ranging from 10% to 46%. The median detection period for recurrence ranged from 12 months to 22 months. Imaging detection of disease generally preceded formal clinical examination. This operational sequence means that patients typically undergo imaging studies before consulting their providers, allowing the provider to review the imaging results prior to performing a physical exam; thus, clinical examination findings were not integrated into this assessment, Randall noted. However, the inclusion of ultrasound imaging scheduled between scheduled MRI scans was shown to facilitate an earlier average detection of recurrence, speeding up the local recurrence detection timeline by 3 to 6 months compared with standard MRI surveillance schedules.