[Imaging features of lung carcinoma, pulmonary tuberculoma, and inflammatory pseudotumor on helical incremental dynamic CT scan--a report of 44 cases].

Background & Objective: Lung carcinoma, pulmonary tuberculoma, and inflammatory pesudotumor are the most common solitary pulmonary nodules (SPN). Computed tomography (CT) is the major diagnostic examination of them. Most recent reports focused on their morphologic features on CT. The differential diagnoses are still difficult. This study was to explore their imaging features on helical incremental dynamic CT scan according to the differences of their hematal supply, and get more information for the diagnosis and differential diagnosis.

Methods: Incremental dynamic CT scan was performed on 115 cases of solitary pulmonary nodule. Of the 44 cases proved by postoperative pathology, 30 were lung carcinoma, 7 were pulmonary tuberculoma, and 7 were inflammatory pesudotumor.

Results: Of the 30 cases of lung carcinoma, 7 were mildly enhanced, 14 were moderately enhanced, 5 were highly enhanced, 2 were remarkably enhanced, and 7 were not enhanced; 9 had peak enhancement began at 18-28 s after injection, 17 began at 30-39 s, and 4 began at 40-44 s, with an average time of 32 s. Of the 7 cases of tuberculoma, 5 were not enhanced, and 2 were cricoid enhanced. All the 7 cases of inflammatory pesudotumor were remarkably enhanced, with the peak enhancement value of over 100 Hu in all cases; the peak enhancements began at 26 s, 28 s, 30 s, 32 s, 33 s, 110 s, and 122 s, respectively, after injection.

Conclusion: Helical incremental dynamic CT is helpful in differential diagnoses of lung carcinoma, pulmonary tuberculoma, and inflammatory pesudotumor.