Radiographic staging of sarcoidosis has traditionally been based upon the finding on plane CXR. We compared CXR findings with those of CT scan in confirmed cases of sarcoidosis in order to assess whether CXR underestimated parenchymal disease.
We retrospectively reviewed CXRs, CT-scans and single-breath diffusing capacity (DLCO) in 73 patients (51 females, 22 males, age range:27–60 years; mean age:45.3 years) with biopsy-proven sarcoidosis.
Based on CXR findings, all cases were categorized as follows: stage I: 42 (58%), stage II: 17 (23%), stage III: 14 (19%). Of 42 cases categorized as stage I on CXR, 34 (81%) had stage I disease on CT scan while remaining 8 (19%) were actually stage II by CT scan. All of the 17 cases categorized as stage II by CXR were also stage II by CT scan. Of 14 cases classified as stage III by CXR, 13 (93%) were stage III by CT scan while 1 (7%) had stage II disease. Of 34 cases categorized as stage I on CXR as well as CT scan, only 4 (12%) showed impairment in DLCO. Of 8 cases categorized as stage I on CXR but stage II on CT scan, 6 (75%) showed impairment in DLCO (*P=0.0001).
Proportions compared by Z-test; α set at 0.05.
CXR correctly diagnosed 81% of stage I sarcoidosis while CT scan diagnosed 100% of Stage 1 disease (*P=0.009). Underdiagnosis of stage II disease by CXR was also reflected by impairment in DLCO among incorrectly classified Stage II cases.CLINICAL IMPLICATION: CT scan should replace CXR for accurate staging of sarcoidosis because CXR underestimates parenchymal disease.
G. Wardeh, None.