Transcranial Doppler sonographic findings in granulomatous meningoencephalitis in small breed dogs

Abstract

Granulomatous meningoencephalitis (GME) is an acute, progressive, and often fatal inflammatory disease of the central nervous system, affecting mainly small and toy dog breeds. A definitive diagnosis of GME can only be achieved through histopathologic examination of samples collected after death. This retrospective study describes transcranial Doppler ultrasonography (TDS) findings in dogs with confirmed clinical histopathology of GME. Eleven dogs were selected for this study. Sonographic findings in B-mode demonstrated diffuse decreased brain parenchyma echogenicity in 9 dogs, ventriculomegaly in 8 dogs, brain atrophy in 4 dogs, and hyperechoic focal lesions in 6 dogs. Color Doppler imaging revealed more obvious vessels of the arterial circle in 10 dogs. Spectral Doppler examination was performed in 10 dogs to detect the 6 major cerebral arteries of interest. The examination showed normal and high resistive index (RI) values in the outlined arteries. The TDS findings were consistent with pathology found on postmortem examination.

Figure 1

Transtemporal window, dorsal plane. Note the lateral symmetrical ventriculomegaly. LLV — left lateral ventricle, RLV — right lateral ventricle (1, 2 — width of lateral ventricles).

Figure 2

Transtemporal window, oblique dorsal plane. Note between the “x” marks, increased echogenicity areas that demonstrate focal lesions. RCH — right cerebral hemisphere, LCH — left cerebral hemisphere.

Figure 3

Transtemporal window, oblique dorsal plane. Note that color Doppler imaging was performed to identify the arterial circle. RCA — rostral cerebral artery, MCA — middle cerebral artery, CCA — caudal cerebral artery, LCH — left cerebral hemisphere.

Figure 4

Transtemporal window, oblique dorsal plane. Note the normal typical Doppler spectral waveform of the Rostral Cerebral Artery: low resistance and high diastolic velocity pattern. PSV — peak systolic velocity, EDV — end diastolic velocity, RI — resistive index, LCH — left cerebral hemisphere.