Magnetic resonance imaging features of presumed intracerebral hemorrhages in dogs show a significant association between apparent diffusion coefficient peripheral layer and estimated bleeding age and commonly exhibit a T2 blackout effect.

In humans, intracranial hematomas commonly exhibit a T2 blackout effect (BOE) with diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) maps. Published descriptions of comparable findings in dogs with intracerebral hemorrhages are lacking. Aims of this retrospective observational study were to describe the appearance of presumed intracerebral hemorrhages (PICHs) in DWI regardless of the underlying etiology and presence of T2 blackout effect (T2 BOE) in dogs and to test potential associations with DWI and ADC findings versus the estimated age of the hemorrhage. Magnetic resonance imaging studies of dogs with presumed PICHs based on the combined evaluation of T2*W gradient echo and/or susceptibility-weighted imaging, T1W and T2W images were enrolled. The age of the hemorrhage was estimated according to published criteria based on T1W and T2W sequences. The association between the age of the hemorrhage and the appearance of each finding (stratified or mixed), their signal intensities in DWI/ADC and the presence of the T2 BOE, was evaluated. A total of 35 PICHs were included: 13 of them were stratified and 22 had a mixed aspect. Only the ADC appearance of the peripheral layer in stratified PICHs was significantly associated with estimated age of the hemorrhage (p = .033), being hypointense in all hyperacute cases and hypo-/isointense in acute cases. The T2 BOE was present in 29/35 PICHs. The DWI sequences showed limited utility to date PICHs in this study population. As in humans, the T2 BOE was commonly seen in DWI and ADC maps of dogs with PICHs.

MRI and CT features of a disc herniation through a fractured lumbar vertebra causing lumbar spinal cord compression in a dog.

A 5-year-old intact male Saint Bernard was presented for paraparesis following a fall down the stairs. Magnetic resonance imaging revealed a chronic fragmentation of the dorsocaudal aspect of the second lumbar vertebral body (L2). Material migrated from the L2 to L3 intervertebral space through the fractured caudal vertebral endplate into the vertebral body and reached the vertebral canal, resulting in a severe extradural compressive myelopathy. Computed tomography confirmed the vertebral fragmentation. Histology of surgically removed compressive material revealed fibrocartilaginous material. The uncommon route of the extruded disc material through a fractured vertebral body makes this case of traumatic disc extrusion unusual.

Can MRI differentiate between ring-enhancing gliomas and intra-axial abscesses?

Gliomas of the brain may appear as expansile ring-enhancing masses in MRI studies, mimicking the appearance of intra-axial abscesses. The aims of this study were to compare the MRI features of ring-enhancing gliomas and intra-axial brain abscesses in dogs and cats and to identify the characteristics that might help differentiate them. For this multicenter, retrospective, and observational study, the inclusion criteria were as follows: (a) a definitive diagnosis of glioma or abscess based on cytological or histopathological examination following CSF collection or surgical biopsy/necropsy, respectively; (b) MRI study performed with a high- or low-field MRI scanner, including a same plane T1W pre- and postcontrast, a T2W and a T2 FLAIR sequence in at least one plane. If available, delayed T1W postcontrast, T2*W GE, DWI/ADC, and SWI sequences were also evaluated. Sixteen patients were diagnosed with ring-enhancing gliomas, and 15 were diagnosed with intra-axial abscesses. A homogenous signal on T1W (P = 0.049) and T2W (P = 0.042) sequences, a T2W (P = 0.005) or T2*W GE (P = 0.046) peripheral hypointense halo, and an even enhancing capsule (P = 0.002) were significantly associated with brain abscesses. A progressive central enhancement on delayed T1W postcontrast sequences was correlated with ring-enhancing gliomas (P = 0.009). The combination of the following features was suggestive of brain abscess: homogeneous T1W or T2W signal intensity, a T2W or T2*W GE peripheral hypointense halo and an evenly enhancing capsule. Central progression of enhancement on delayed T1W postcontrast sequences was suggestive of glioma.

Negative hepatic computed tomographic attenuation pattern in a dog with vacuolar hepatopathy and hepatic fat accumulation secondary to cushing's syndrome.

This report describes an unusual computed tomographic (CT) hepatic pattern, characterized by negative attenuation values (from -19.59 to -28.85 Hounsfield Units, HU) in a canine patient with severe Cushing's syndrome. Attenuation values of the splenic parenchyma (63.26 HU) and abdominal fat (-118.34 HU) were within normal limits. The negative hepatic attenuation values allowed a CT diagnosis of severe hepatic fatty infiltration that was subsequently confirmed by tissue-core biopsy and histopathological examination.

Prevalence, MRI findings, and clinical features of lumbosacral intervertebral disc protrusion in French Bulldogs diagnosed with acute thoracic or lumbar intervertebral disc extrusion.

Introduction: Intervertebral disc protrusion (IVDP) is a neurological disorder commonly observed at the lumbosacral junction of old, medium-to-large breeds, non-chondrodystrophic dogs. Although uncommon, lumbosacral IVDP can also be seen in chondrodystrophic dogs, among them French Bulldogs (FBs) and could be associated with congenital vertebral malformations in this breed. This study aims to evaluate the prevalence, clinical features, and MRI characteristics of lumbosacral IVDP and congenital vertebral malformations in FBs diagnosed with thoracic or lumbar intervertebral disc extrusion (IVDE) and to evaluate the possible interference of the neurologic deficits related to chronic IVDP on neurological examination. Materials and methods: This is a single-center, retrospective case series. A search for FBs diagnosed with IVDE affecting the thoracic or lumbar regions is done on the database of the AniCura I Portoni Rossi Veterinary Hospital (Zola Predosa, Bologna, Italy). Eligible dogs have a complete medical report and a high-field MRI of the lumbosacral junction. MRIs of the lumbosacral junction are evaluated to determine the position of IVDP, cranial intervertebral foraminal stenosis, and signs of nerve root involvement. Radiographs, when available, are reviewed to identify the presence of lumbosacral congenital vertebral malformations. Results: Eighty FBs are included in the study. The prevalence of lumbosacral IVDP among FBs is 91.3%. Among FBs with lumbosacral IVDP, 45.0% show concurrent cranial intervertebral foraminal stenosis, 28.8% exhibit concurrent nerve root involvement, 56.2% appear to be asymptomatic for lumbosacral changes, while 15.1% manifest a decreased or absent withdrawal reflex as a supposed consequence of chronic lumbosacral IVDP. Congenital vertebral malformations are detected in 10 dogs. Conclusion: The results of this study support the hypothesis that lumbosacral IVDP is frequent in FBs presenting with thoracic or lumbar IVDE. In over half the dogs lumbosacral IVDP appears to be asymptomatic; however, in other cases, chronic lumbosacral IVDP seems to cause neurological deficits that may lead to erroneous localization of acute IVDE, representing a confounding factor for clinicians.

Triple-Phase Multidetector Computed Tomography in Distinguishing Canine Hepatic Lesions.

The liver has a unique vascular supply, and triple-phase contrast-enhanced computed tomography examinations are being performed in order to characterize liver lesions. This study aimed to look for any associations between the attenuation values of liver lesions and their histological classification. The inclusion criteria for this retrospective study were focal or multifocal liver lesions and histological diagnosis. All of the dogs underwent pre-contrast and triple-phase postcontrast computed tomography (CT) examinations with identical timings of the postcontrast series. Thirty-one dogs were included in the study, and various benign and malignant pathologies were identified. The results did not identify any significant differences between the benign and malignant liver lesions, nor between the individual histological diagnoses. Inflammatory lesions were significantly different compared to the normal liver parenchyma, and significant hypoattenuation was found in the portal and delayed venous phases. Hemangiosarcomas were significantly hypoattenuating to the normal liver parenchyma in the pre-contrast and arterial phases, and also to all of the benign lesions in the arterial phase. The other pathologies showed variable attenuation patterns in the different postcontrast phases, and differentiation was not possible. On the basis of this study, triple-phase contrast-enhanced computed tomography cannot differentiate between benign and malignant liver lesions, and biopsy and further histological analysis are necessary.

Prevalence, distribution, and clinical characteristics of hemangiosarcoma-associated skeletal muscle metastases in 61 dogs: A whole body computed tomographic study.

BACKGROUND: Skeletal muscle metastases (SMMs) have been described sporadically in canine oncology. HYPOTHESIS/OBJECTIVES: To determine the prevalence, localization, and clinical signs of SMMs associated with hemangiosarcoma (HSA) in a population of dogs presented for whole body computed tomography (CT). ANIMALS: Dogs with a histologically confirmed HSA and a tissue core specimen or fine needle aspirate of suspected metastatic lesions were included in the study. METHODS: Retrospective study. Dogs with a final diagnosis of visceral or muscular HSA that underwent whole body CT scan were enrolled in the study. Final diagnosis of primary tumor and SMMs was reached by histology, cytology, or both. Signalment, clinical signs, localization of the primary lesion, and metastases characteristics were reviewed. RESULTS: Sixty-one dogs met the inclusion criteria. Skeletal muscle metastases were detected in 15 dogs (24.6%) and all of these dogs had also metastases in ≥1 sites. Presence of SMMs was significantly higher in males but was not significantly related to age, neuter status, breed, localization, and dimensions of the primary tumor. Nine of 15 (60.0%) dogs with SMMs showed lameness or reluctance to move whereas these signs were not recorded in any of the 42 dogs without SMMs (P < .001). CONCLUSION AND CLINICAL IMPORTANCE: Prevalence of SMMs in our population of dogs with HSA was higher in comparison to previous studies in the human and veterinary medical literature. Whole body CT is recommended for staging of dogs with HSA, because SMMs could be missed by clinical examination and traditional diagnostic imaging modalities.