Quantitative Computed Tomography (CT) Analysis of Pulmonary Pattern in Dogs Affected by Pneumonia, Before and After Intravenous Contrast Medium Administration
Alveolar pattern of the lung field is usually caused by several lung involvements such as edema, hemorrhage and pneumonia, but differentiation using radiography is usually impossible.
Evaluation of Hounsfield unit (HU) and lung pattern of pneumonia in dogs using computed tomography (CTscan) technique and confirmation by CT-assisted fine needle aspiration (FNA) as a safe diagnostic procedure.
In this study, 10 dogs with respiratory distress suspected for pneumonia were selected and radiography and counting blood cells (CBC) were used for evaluation of lung pattern and cytology. Before and after contrast medium injection, CT-scans of the lung field were achieved. Finally in transverse CT sections, FNA of involved lung lobes was taken for cytologic evaluation. After the confirmation of pneumonia, CT scans reevaluated with more attention and pulmonary pattern was described. HU of involved regions were measured.
In all of patients, ventral region of the lungs especially cranial and middle lung lobes were involved. The involvement of left lungs were prominent. The mean HU of healthy lung was -778, and HU of unhealthy lung parenchyma before contrast medium study was between 31 till 39, after contrast study was between 46 till 70. It means the HU has been significantly increased. Also the contrast of the involved lung regions was increased which this helped to differentiate the unhealthy lung tissue from the adjacent soft tissues. Hematology tests in all of the patients were represented the infection.
Both CT-scan and CT-assisted-FNA from the lung, for the diagnosis of pulmonary disorders such as pneumonia, are beneficial and practical methods.