Annals of Nuclear Medicine

, Volume 23, Issue 6, pp 569–577 | Cite as

Characterization of thymic masses using 18F-FDG PET-CT

  • Arvind Kumar
  • Subodh Kumar Regmi
  • Roman Dutta
  • Rakesh Kumar
  • Siddhartha Datta Gupta
  • Prasenjit Das
  • Dhanapathi Halanaik
  • Tarun Jindal
Original Article

Abstract

Background

The resectability and survival may be improved in thymoma and thymic carcinoma with multimodality therapy. Various diagnostic imaging modalities are required for accurate diagnosis and preoperative staging of thymic masses. The present prospective study was planned to evaluate if Fluorodeoxyglucose (FDG) PET-CT can help differentiate various thymic lesions noted on conventional imaging modalities.

Methods

A prospective study was undertaken in 23 patients who had shown either an anterior mediastinal mass consistent with thymic origin or suspicious for a thymic mass on contrast-enhanced computed tomography scan. All patients underwent whole body FDG PET-CT after intravenous injection of 370 MBq of FDG. The interpretation of PET-CT images was based on the following criteria: FDG uptake (present or absent), SUVmax, pattern of uptake, invasion to surrounding structures, presence of metastasis and necrosis. The results of PET-CT were correlated with the final histopathology following surgery. Statistical analysis was performed with SPSS 11.5 for Windows software. The mean SUVmax of the 3 groups of pathology was compared using the Kruskal–Wallis Test.

Results

Thymic hyperplasia had an enlarged thymus with mean SUVmax of 1.1. Low risk thymoma had large tumors and their mean SUVmax was 3. High risk thymoma had small tumors with mean SUVmax of 2.1. As a group, thymoma had mean SUVmax value of 2.3. All thymic carcinomas were large, and their mean SUVmax was 7. The difference between the mean SUVmax for thymic hyperplasia, thymoma and thymic carcinoma was statistically significant. The difference between the SUVmax of high risk and low risk thymoma was not significant.

Conclusion

18F-FDG PET-CT can help characterize various thymic lesions noted on conventional imaging modalities. However, larger prospective studies are further required to substantiate these findings.

Keywords

FDG PET-CT Thymic carcinoma Thymoma Thymic hyperplasia 

Abbreviations

PET-CT

Positron emission tomography computed tomography

FDG

Fluorodeoxyglucose

SUVmax

Maximum standardized uptake value

FWHM

Full-width half maximum

MBq

Mega Becquerel

VATS

Video-assisted thoracoscopic surgery

Notes

Acknowledgments

This project was supported by All India Institute of Medical Sciences, New Delhi, India.

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Copyright information

© The Japanese Society of Nuclear Medicine 2009

Authors and Affiliations

  • Arvind Kumar
    • 1
  • Subodh Kumar Regmi
    • 1
  • Roman Dutta
    • 1
  • Rakesh Kumar
    • 2
  • Siddhartha Datta Gupta
    • 3
  • Prasenjit Das
    • 3
  • Dhanapathi Halanaik
    • 2
  • Tarun Jindal
    • 1
  1. 1.Department of Surgical DisciplinesAll India Institute of Medical SciencesNew DelhiIndia
  2. 2.Department of Nuclear MedicineAll India Institute of Medical SciencesNew DelhiIndia
  3. 3.Department of PathologyAll India Institute of Medical SciencesNew DelhiIndia

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