Relationships Among Subgross Anatomy, Computed Tomography, and Histologic Findings in Dogs With Disease Localized to the Pulmonary Acini

Abstract

During computed tomography (CT), the appearance of disease involving the pulmonary acinus may be described using terms such as atelectasis, ground-glass opacity, or consolidation. These CT signs, however, have not been correlated with histologic findings in canine pulmonary disease. To facilitate interpretation of lung diseases by CT signs, our goals were to review the morphologic organization of the lung and evaluate the medical records of four dogs with different types of pulmonary acinar disease. Anatomic review focused on understanding the pulmonary acinus and the secondary pulmonary lobule; the secondary pulmonary lobule is a fundamental unit for interpretation in people. All dogs had similar CT findings of fully expanded lungs with increased attenuation and partial-to-complete obscuring of the pulmonary blood vessels. Histologic findings varied between dogs and included partial-to-complete filling of airspaces with cells or fluid, interstitial thickening, increased capillary blood volume, or a combination of these findings. Final diagnoses were hemorrhagic pneumonia, bronchiolar carcinoma, metastatic mammary adenocarcinoma, and pulmonary edema. In summary, the morphologic organization of the lungs is complex and has implications for diagnostic interpretation needing further evaluation in dogs. In this study, increased lung attenuation during CT due to disease localized to the pulmonary acini was due to the displacement of air from the lungs and not to the microscopic distribution of lesions within the pulmonary acinus. Imaging descriptors that classify diseases according to structures larger than the pulmonary acini, for example, regions of the secondary pulmonary lobule or larger, may be appropriate for dogs.

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“…Dogs are similar to cats and also lack secondary pulmonary lobules, and the pulmonary acinus has been suggested to be the important highresolution CT (HRCT) unit of the canine lung. 26 The acinus is defined as the region of the lung supplied by a single terminal bronchiole, representing the smallest functional unit of the lung. Because it is smaller than the secondary pulmonary lobule that is the smallest visible structure on HRCT, we believe that the pulmonary acinus is not a replaceable term as the important HRCT unit of the feline (or canine) lung.…”

Bronchoalveolar lavage affects computed tomographic and radiographic characteristics of the lungs in healthy dogs

“…Computed tomography (CT) is a sensitive diagnostic tool to localize lung lesions because of its high spatial resolution without superimposition. Because it provides information on airway structure and lung parenchyma, CT use to investigate respiratory symptoms has been increasing in veterinary medicine .…”

Serial CT features of pulmonary leptospirosis in 10 dogs

“…We could observe how solid c­onsolidations on D0 scans had transformed into GGO three days later. This change from airspace consolidation to ground-glass opacity has been reported in sequential thoracic radiographs in people with LPHS (Im and others 1989) and may reflect degrees of airspace filling (Scrivani and others 2012). Solid nodules and ground-glass nodules were found in 8/10 and 10/10 dogs on their initial scan, respectively.…”