J Korean Orthop Assoc.  2021 Oct;56(5):398-403. 10.4055/jkoa.2021.56.5.398.

Availability of Positron Emission Tomography–Computed Tomography for the Diagnosis of the Soft Tissue Tumor through Ultrasound-Guided Biopsy

• Jun SB
• Kim JI
• Lee IS
• Song YS
• Choi KU

• KMID: 2521205
• DOI: http://doi.org/10.4055/jkoa.2021.56.5.398

Abstract

Purpose
A biopsy is needed to diagnose soft tissue tumors. However, it is extremely difficult to pinpoint the site of a tumor due to the heterogeneity of sarcomas. Thus, even when an open biopsy is conducted, it is difficult to diagnose a soft tissue tumor. In such cases, an ultrasound (US)-guided biopsy is used to improve the diagnostic accuracy. This study evaluated the accuracy of US-guided biopsy for a diagnosis of soft tissue tumors found initially in a magnetic resonance (MR) perfusion and assessed the availability of positron emission tomography–computed tomography (PET–CT) for a diagnosis of soft tissue tumors.
Materials and Methods
From January 2014 to December 2018, the US-guided biopsy was performed on 152 patients with a suspected soft tissue tumor found in an MR perfusion and 86 cases were definitively diagnosed with a soft tissue tumor. The accuracy of the US-guided biopsy was assessed retrospectively. Among the 86 cases, only MR perfusion was used before the biopsy in 50 cases, while both MR perfusion and PET–CT was conducted on 36 cases. The accuracy was analyzed to determine if the PET–CT could improve the precision of a biopsy.
Results
From 86 cases, 34 out of 50 cases, in which only MR perfusion had been conducted, matched the result of the definitive diagnosis and the US-guided biopsy. 32 out of 36 cases, in which both PET–CT and MR perfusion were conducted, matched the definitive diagnosis and the US-guided biopsy. These results show significant differences in the accuracy of US-guided biopsy. In the case of soft tissue sarcomas, 6 out of 12 cases, in which only MR perfusion had been conducted, matched the result of the definitive diagnosis and the USguided biopsy. 17 out of 18 cases, in which both PET–CT and MR perfusion were conducted, matched the definitive diagnosis. Moreover US-guided biopsy also showed significant differences in the accuracy of US-guided biopsy.
Conclusion
In diagnosing soft tissue tumors, a US-guided biopsy is a well-known tool for its high accuracy. However, the heterogeneity of sarcoma makes it difficult to locate the exact site for a biopsy using only MR perfusion. Thus, the use of PET–CT will meaningfully improve the accuracy of a diagnosis by precisely targeting the site for the US-guided biopsy.

Keyword

sarcoma; soft tissue tumor; ultrasound-guided biopsy; positron emission tomography computed tomography; magnetic resonance perfusion