PURPOSE: To retrospectively compare diagnostic value of coregistered fluorine 18 fluorodeoxyglucose positron emission tomographic (PET) and computed tomo-graphic (CT) scans obtained with low-dose nonenhanced CT (PET/CT) with those routinely obtained with contrast material-enhanced CT for staging and restaging of disease in patients with Hodgkin disease or high-grade non-Hodgkin lymphoma.
MATERIALS AND METHODS: Sixty patients (mean age, 39.6 years � 17.1 [standard deviation]) with Hodgkin disease (n = 42) or high-grade non-Hodgkin lymphoma (n - 18) were included in this retrospective study. AJI patients underwent PET/CT and contrast-enhanced CT within a maximum of 24 days (mean, 9.1 days � 7.0) of each other for staging (n - 19) or first follow-up examination (n = 41). Findings were extracted from original written reports (PET/CT, contrast-enhanced CT) and compared with findings of reference standard, which included biopsy or follow-up with clinical, laboratory, or other imaging findings. For statistical analysis, sensitivity and specificity were calculated with findings of the reference standard. Agreement of both methods was determined with Cohen K and McNemar tests on a per-patient basis.
RESULTS: For evaluation of lymph node involvement, sensitivity of PET/CT and contrast-enhanced CT was 94% and 88%, and specificity was 100% and 86%, respectively. For evaluation of organ involvement, sensitivity of PET/CT and contrast-enhanced CT was 88% and 50%, and specificity was 100% and 90%, respectively. Agreement of both methods was excellent (K = 0.84) for assignment of lymph node involvement but only fair (K = 0.50) for extranodal disease. A difference with P < ,05 (McNemar test) was considered significant in regard to exclusion of disease with PET/CT, compared with contrast-enhanced CT.
CONCLUSION: PET/CT performed with nonenhanced CT is more sensitive and specific than is contrast-enhanced CT for evaluation of lymph node and organ involvement, especially regarding exclusion of disease, in patients with Hodgkin disease and high-grade non-Hodgkin lymphoma.