Detection of skeletal muscle metastasis: torso FDG PET-CT versus contrast-enhanced chest or abdomen CT

Acta Radiol. 2015 Jul;56(7):860-6. doi: 10.1177/0284185114556927. Epub 2014 Nov 18.

Abstract

Background: Skeletal muscle metastasis (SMM) in cancer patients has not been sufficiently evaluated regarding prevalence and proper method of detection.

Purpose: To determine the prevalence of SMM and compare the diagnostic competencies for SMM of torso F-18 fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET-CT) and contrast-enhanced chest or abdomen CT.

Material and methods: We investigated 18,225 PET-CT studies of 6359 cancer patients performed from 2005 to 2012. The PET-CT studies describing potential SMM were retrieved and the corresponding medical records were reviewed. The gold standard for SMM was histopathologically-proven SMM or imaging study-based disease progression. The detectability of SMM was compared between PET-CT and contrast-enhanced CT.

Results: Twenty-six patients had 84 SMM lesions, representing a SMM prevalence of 0.41%. Lung cancer was the most common SMM-associated malignancy (54%) and the gluteal/pelvic girdle muscle was the most frequently involved SMM site (37%). All 84 SMM lesions were visualized on PET-CT (100%). Of these PET-CT positive 84 SMM lesions, 51 lesions were in the CT field of view (FOV) (61%), whereas 33 lesions were out of the CT FOV (39%). Among these 51 lesions, 17 lesions showed rim-enhancing nodules/masses (33%), eight lesions showed homogeneously enhancing nodules (16%), three lesions showed heterogeneously enhancing nodules (6%), and 23 SMM lesions (45%) were non-diagnostic by CT. All 51 SMM lesions within CT FOV were detected on PET-CT (100%), whereas only 28 were visualized on CT (54.9%), resulting in a significant difference (P < 0.005). On average, 2.6 more organs with concomitant metastases were found when SMM was revealed by PET-CT.

Conclusion: The prevalence of SMM was as low as 0.41% in the current large cohort of cancer patients. Torso PET-CT was a more competent modality than contrast-enhanced CT in the detection of SMM.

Keywords: Computed tomography (CT); malignancy; metastasis; neoplasm; positron emission tomography-computed tomography (PET-CT); skeletal muscle.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Contrast Media*
  • Female
  • Fluorodeoxyglucose F18*
  • Humans
  • Korea / epidemiology
  • Male
  • Middle Aged
  • Multimodal Imaging / methods
  • Muscle Neoplasms / diagnosis*
  • Muscle Neoplasms / secondary*
  • Muscle, Skeletal / diagnostic imaging
  • Positron-Emission Tomography*
  • Prevalence
  • Radiographic Image Enhancement / methods
  • Radiography, Abdominal
  • Radiography, Thoracic
  • Radiopharmaceuticals
  • Reproducibility of Results
  • Retrospective Studies
  • Tomography, X-Ray Computed*
  • Torso / diagnostic imaging

Substances

  • Contrast Media
  • Radiopharmaceuticals
  • Fluorodeoxyglucose F18