Lung perfusion with dual-energy multi-detector row CT: can it help recognize ground glass opacities of vascular origin?

Rationale and objectives: The aim of this study was to evaluate whether the spectral characterization of the iodine content of lung microcirculation could help identify ground-glass opacity (GGO) of vascular origin.

Materials and methods: Thirty-five consecutive patients with GGO of bronchioloalveolar (group 1; n = 24) and vascular (group 2; n = 11) origin underwent dual-energy multi-detector computed tomographic angiography of the chest using a standard injection protocol. For each patient, two radiologists evaluated by consensus the presence, location, and extent of GGO on diagnostic computed tomographic scans (ie, contiguous 1-mm-thick averaged images from both tubes) and characteristics of the corresponding areas on perfusion scans.

Results: A total of 443 segments with GGO were depicted on the diagnostic scans (group 1, n = 231; group 2, n = 212), always intermingled with areas of normal lung attenuation, with a mean of 12.7 segments with GGO per patient. Areas of GGO were located at the level of the upper lobes (n = 128), middle lobe and/or lingula (n = 81), and lower (n = 234) lobes, involving <25% (n = 165), 25% to 50% (n = 103), 50% to 75% (n = 155), and >75% (n = 20) of the segmental surface. The overall quality of perfusion scans was rated as interpretable in all patients. Perfusion scans depicted areas of hyperattenuation within segments of GGO with a significantly higher frequency in group 2 (211 of 212 [99.5%]) than in group 1 (27 of 231 [12%]) (P < .0001). Hyperattenuated areas of vascular origin were observed to match the areas of GGO in surface (203 of 211 [96%]) and contours (208 of 211 [98.6%]).

Conclusion: Dual-energy computed tomography can help recognize GGO of vascular origin.