Efficacy of PET/CT to exclude leiomyoma in patients with lesions suspicious for uterine sarcoma on MRI

Taiwan J Obstet Gynecol. 2017 Aug;56(4):508-513. doi: 10.1016/j.tjog.2017.05.003.

Abstract

Objective: To analyze the efficacy of positron emission tomography/computed tomography (PET/CT) for the diagnosis of uterine sarcoma.

Materials and methods: Thirty-four patients evaluated between January 2010 and March 2015 were retrospectively enrolled. All patients in whom uterine sarcoma was suspected based on contrast-enhanced magnetic resonance imaging (MRI) findings (heterogeneous, high signal intensity on T2-weighted images and/or high intensity on T1-weighted images) underwent PET/CT for further assessment. Patients were divided into 2 groups based on postoperative pathological findings: uterine sarcoma (n = 15) and leiomyoma (n = 19). The maximum standardized uptake value (SUVmax) of all lesions was measured using PET/CT; we calculated the optimal cutoff value for diagnosing sarcoma.

Results: The median SUVmax for uterine sarcoma and leiomyoma was 12 and 4.1, respectively; these values were significantly different. An SUVmax of greater than 7.5 was able to exclude leiomyoma with 80.8% sensitivity and 100% specificity (area under the curve, 95.3%). A cutoff SUVmax of 7.5 yields 100% specificity, and a cutoff SUVmax of 4.4 yields a 100% negative predictive value (NPV). The combination of PET/CT and lactate dehydrogenase (LDH) levels had a sensitivity of 86.6%, specificity of 100%, positive predictive value of 100%, and an NPV of 90.4%. No relation between histopathology or International Federation of Gynecology and Obstetrics (FIGO) stage and 18-fluoro-2-deoxy-d-glucose uptake value on PET/CT was seen. The surgical outcome trended toward a correlation with the SUVmax, although this was not statistically significant.

Conclusions: In patients with MRI findings consistent with either uterine sarcoma or leiomyoma, PET/CT can decrease the false-positive rate by setting an optimal cutoff SUVmax of 7.5. Using this cutoff can avoid unnecessary surgery.

Keywords: Leiomyoma; MRI; PET/CT; Uterine sarcoma.

Publication types

  • Evaluation Study

MeSH terms

  • Adult
  • Aged
  • Area Under Curve
  • False Positive Reactions
  • Female
  • Fluorodeoxyglucose F18
  • Humans
  • Leiomyoma / diagnostic imaging*
  • Magnetic Resonance Imaging*
  • Middle Aged
  • Positron Emission Tomography Computed Tomography*
  • Radiopharmaceuticals
  • Reference Values
  • Retrospective Studies
  • Sarcoma / diagnostic imaging*
  • Sensitivity and Specificity
  • Uterine Neoplasms / diagnostic imaging*

Substances

  • Radiopharmaceuticals
  • Fluorodeoxyglucose F18