Case report: Application of color Doppler sonography for the assessment of pulmonary consolidations in a dog

Abstract

A 1,5-year-old male Maltipoo was presented to the emergency service for dyspnea, weakness, and cough. An echocardiographic examination showed evidence of pulmonary hypertension with a McConnell sign. Lung ultrasound, including color Doppler, was performed and identified two distinct populations of lung consolidation. Color Doppler analysis of the first type of consolidation showed the absence of blood flow within regions of the consolidation and flow amputation. These findings were consistent with the "vascular sign" reported in human medicine and prompted consideration of pulmonary thromboembolism as a differential diagnosis. In the second type of consolidation, color Doppler identified blood flow within the pulmonary vessels of the consolidated lung, forming a "branching tree-like" pattern that followed the anatomical course of the pulmonary vasculature. These findings suggested that blood flow was preserved within the pulmonary vasculature of the consolidated lung and prompted consideration of inflammatory causes of pulmonary pathology. On recheck 6 days later, recanalization of the first type of consolidation was identified with color Doppler. The case was followed serially once a month for 5 months with LUS, which showed continued improvement. Based on a positive fecal Baermann test, a final diagnosis of Angiostrongylus vasorum was made. New or Unique information Provided-this is the first report of color Doppler LUS being used to characterize and help differentiate the cause of lung consolidation in dogs.

Keywords: color Doppler; consolidation; dog; lung ultrasonography (LUS); thromboembolic disease.

Figure 1

Diagram showing lung ultrasound examination protocol.

Figure 2

Color doppler still image of a triangular shaped consolidation within the lung referred to as a “wedge sign”. An absence of blood flow within the consolidated region is visible, giving the impression the blood flow is “amputated” (↑), which is referred to as the “vascular sign”. A comet-tail artifact (C-line) extends from the lower edge of the consolidation (←). Short artifacts originating at the pleural line (→) are also visible, referred to as I-lines. Finally, hyperechoic vertical artifacts, believed to be B-lines are also visible (*). To confirm these are B-lines the depth should be extended (10-15 cm) to ensure these vertical white artifacts continue to reach the far field. Performed at presentation. Thyroid presets.

Figure 3

Color doppler imaging of the triangular lung consolidation “wedge sign”, demonstrating recanalization of the consolidation over time (↑), (→) spared areas. Performed on day 6-recheck. Thyroid presets.

Figure 4

Color doppler still image of a triangular shaped consolidations “wedge sign” with a no flow, long hypoechogenic consolidation (A). Early recanalization of the consolidation using color doppler was seen 6 days following initiation of therapy (→) (B). Lung presets.