Description and clinical relevance of the variable conformation of canine spinal arachnoid diverticula.

The conformation of spinal arachnoid diverticula (SAD) and their clinical implications are poorly characterized in dogs. This retrospective cross-sectional study describes different SAD conformations in dogs and aims to identify if there is an association between SAD conformation and clinical features, localization, syringomyelia (SM) presence, concurrent vertebral condition, treatment option, and short as well as long-term outcome. Sixty-two dogs were included (12 cervical and 50 thoracolumbar SAD). All dogs with a cervical SAD had a cranial tethered conformation and were not included in the statistical analysis. Half of the dogs with a thoracolumbar SAD were cranial tethered, and the other half were caudal tethered. SM associated with SAD had a moderate prevalence in the cervical region (58.3%) and a high prevalence in the thoracolumbar region (82%). All dogs with the presence of SM and caudal tethered SAD had a cranial positioned SM, and all dogs with SM and a cranial tethered SAD had a caudal positioned SM. The SM absolute length and SM length/L2 ratio were significantly higher (P = .018, respectively) in the caudal tethered SAD compared with the cranial tethered SAD. The short-term outcome was statistically different (P = .045) between caudal and cranial tethered thoracolumbar SAD, but not the long-term outcome (P = .062). Multivariable logistic regression identified thoracolumbar caudal tethered SAD conformation had a better short-term outcome (P = 0.017, OR: 0.043, CI: 0.003-0.563), independently of SM length measurements. SAD conformation in dogs can influence SM formation. A possible link between short-term outcome and SAD conformation was found, but further research is warranted.

Confirmed and presumed canine insulinomas and their presumed metastases are most conspicuous in the late arterial phase in a triple arterial phase CT protocol.

Arterial enhancement is the commonly described characteristic of canine insulinomas in contrast-enhanced computed tomography (CECT). However, this finding is also reported as inconsistent. The main aim of this single-center retrospective observational study was to describe the contrast enhancement (CE) pattern of canine presumed and confirmed insulinomas and presumed metastases in three consecutive (early, mid, and late) arterial phases. Included dogs had a medical-record-based clinical or cytological/histopathological diagnosis of insulinoma and quadruple-phase CECT. The arterial phases were identified according to published literature. The arterial enhancement of confirmed and presumed lesions was assessed using a visual grading score. Twelve dogs with a total of 17 pancreatic nodules were analyzed. Three dogs had multiple pancreatic nodules and nine had solitary findings. Four insulinomas were histopathologically confirmed. Late arterial phase (LAP) images demonstrated the largest number of pancreatic nodules reaching the highest enhancement scores (n = 13, 76%). All analyzed dogs had CT evidence of arterially enhancing nodules in the liver (n = 12), seven in the hepatic, splenic, or colic lymph nodes, and three in the spleen. Three out of five sampled livers and three lymph nodes were metastatic. All sampled spleens were benign. Avid arterial enhancement was the most dominant feature of canine presumed and confirmed insulinomas and presumed metastases in quadruple-phase CECT. The highest enhancement scores were observed primarily in LAP, followed by MAP. Authors, therefore, recommend including LAP in the standard CT protocol for dogs with suspected pancreatic insulinomas.

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.

Early CT in dogs following traumatic brain injury has limited value in predicting short-term prognosis.

Traumatic brain injury is associated with a high risk of mortality in veterinary patients, however publications describing valid prognostic indicators are currently lacking. The objective of this retrospective observational study was to determine whether early CT findings are associated with short-term prognosis following traumatic brain injury (TBI) in dogs. An electronic database was searched for dogs with TBI that underwent CT within 72 h of injury; 40 dogs met the inclusion criteria. CT findings were graded based on a Modified Advanced Imaging System (MAIS) from grade I (normal brain parenchyma) to VI (bilateral lesions affecting the brainstem with or without any foregoing lesions of lesser grades). Other imaging features recorded included presence of midline shift, intracranial hemorrhage, brain herniation, skull fractures, and percentage of total brain parenchyma affected. Outcome measures included survival to discharge and occurrence of immediate onset posttraumatic seizures. Thirty dogs (75%) survived to discharge. Seven dogs (17.5%) suffered posttraumatic seizures. There was no association between survival to discharge and posttraumatic seizures. No imaging features evaluated were associated with the study outcome measures. Therefore, the current study failed to identify any early CT imaging features with prognostic significance in canine TBI patients. Limitations associated with CT may preclude its use for prognostication; however, modifications to the current MAIS and evaluation in a larger study population may yield more useful results. Despite this, CT is a valuable tool in the detection of structural abnormalities following TBI in dogs that warrants further investigation.

Heart to spine measurements to detect left atrial enlargement in dogs with mitral insufficiency.

BACKGROUND: Radiography is useful to determine left atrial (LA) size when echocardiography is not available. Recently, the authors have described Radiographic Left Atrial Dimension (RLAD) as a new radiographic measurement to assess LA size. The objective of this study was to assess the clinical usefulness of 2 new radiographic measurements to detect and quantify left atrial enlargement (LAE) compared to RLAD and using left atrium to aortic root (LA/Ao) ratio as gold standard. These new measurements, bronchus-to-spine (Br-Spine) and RLAD-to-spine (RLAD-Spine) may be more precise in cases were LA boundaries are not well defined. Fifty dogs, 25 with and 25 without LAE were recruited. Reference LA/Ao ratio was assessed by 2D echocardiography and LAE was considered if LA/Ao > 1.6. Br-spine was measured as a straight vertical line from the main stem bronchus to the ventral border of the vertebra situated immediately dorsal to the heart base. RLAD-Spine was measured from RLAD endpoint perpendicularly to spine. The correlation of RLAD, Br-Spine and RLAD-Spine methods with LA/Ao and their sensitivity and specificity for detecting LAE were calculated. Receiver Operating Characteristic (ROC) curves were used to estimate the optimal cut-off for each method. RESULTS: Correlations between Br-Spine, RLAD-Spine, RLAD and LA/Ao ratio were - 0.66, - 0.76 and 0.89 respectively (P < 0.001). Sensitivity at the optimal cut-off values for detecting LAE were 32.0, 64.0 and 96.0%, respectively. Specificity was 96.0% in all cases. CONCLUSION: Br-Spine and RLAD-Spine were less sensitive radiographic measurements than RLAD in detecting LAE in dogs. Both Br-Spine and RLAD-Spine may not be good alternatives to RLAD.

A radiographic measurement of left atrial size in dogs.

BACKGROUND: The dimensions of the left atrium in cases with mitral regurgitation are an indirect measurement of its severity. The objective of this study was to evaluate the value of a new radiographic measurement, the radiographic left atrial dimension (RLAD), for detecting left atrial enlargement (LAE) in dogs. Thirty one dogs without LAE and 46 dogs with LAE were recruited in a prospective fashion. Reference left atrium dimension was measured by standard left atrium to aorta ratio (LA/Ao) by 2D echocardiography. LAE was considered if LA/Ao > 1.6. Left atrium dimension was then quantified on lateral radiographs by measuring RLAD. Vertebral heart size (VHS) was measured and RLAD was obtained by drawing a line bisecting the 90 degrees angle defined by the long and short cardiac axes lines of the VHS, up to the dorsal edge of the left atrium and comparing its length to T4's vertebral body length. The correlation of VHS and RLAD methods with LA/Ao was estimated, as well as their sensitivity and specificity for detecting LAE. Receiver Operating Characteristic (ROC) curves were used to estimate the optimal decision criteria for each method. RESULTS: A positive correlation was observed between RLAD and LA/Ao (r = 0.82). RLAD's sensitivity and specificity for detecting LAE when evaluated at the optimal cut-off value, 1.8 vertebrae, were 93.5 and 96.8% respectively. RLAD showed high reproducibility and repeatability. CONCLUSION: RLAD appears to be a clinically useful radiographic measurement for evaluating left atrial dimensions. RLAD would provide clinicians with a simple and cost-effective tool for evaluating and monitoring LAE.

A case series of 37 surgically managed, paraplegic, deep pain negative French bulldogs, with thoracolumbar intervertebral disc extrusion, from two English referral centres.

Background: Thoracolumbar intervertebral disc extrusions (TL-IVDEs) are a common spinal disorder in dogs, especially within chondrodystrophic breeds. Loss of deep pain perception is a well-documented negative prognostic indicator in dogs with TL-IVDE. The objectives of this study were to report the rate of return of deep pain perception and independent ambulation in surgically treated, paraplegic, deep pain perception negative French bulldogs with TL-IVDEs. Methods: A retrospective case series of deep pain perception negative dogs with TL-IVDE presenting to two referral centres between 2015 and 2020 was conducted. Medical and MRI records were reviewed, including the following quantitative MRI changes: lesion length, extent of spinal cord swelling and severity of spinal cord compression. Results: Thirty-seven French bulldogs met the inclusion criteria, with 14 of 37 (38%) regaining deep pain perception by the time of discharge (median hospitalisation 10.0 days [interquartile range 7.0-15.5 days]) with two dogs independently ambulatory (6%). Ten of the 37 dogs were euthanased during hospitalisation. Significantly fewer dogs (3/16, 19%) with L4-S3 lesions regained deep pain perception compared to 11 of 21 (52%) of dogs with T3-L3 lesions (p = 0.048). Quantitative MRI changes were not associated with the return of deep pain perception. After discharge, with a median 1-month follow-up period, an additional three dogs regained deep pain perception and five dogs became independently ambulatory (17/37 [46%] and 7/37 [19%], respectively). Conclusions and clinical importance: This study adds support to the contention that the recovery of French bulldogs with TL-IVDE from surgery is poor compared with other breeds; further prospective, breed-controlled studies are indicated.

What Is Your Diagnosis?

In collaboration with the American College of Veterinary Radiology.

Clinical and magnetic resonance imaging findings in 92 cats with clinical signs of spinal cord disease.

Medical records of 92 cats presented with clinical signs of spinal cord disease, which had undergone magnetic resonance imaging (MRI), were reviewed. The cats were grouped into seven categories based upon the diagnosis suggested by results of MRI, cerebrospinal fluid analysis and other diagnostic procedures: neoplastic (n=25), inflammatory or infectious (n=13), traumatic (n=8), vascular (n=6), degenerative (n=5), anomalous (n=3) and those with an unremarkable MRI (n=32). There were two independent predictors of abnormal MRI findings: severity of clinical signs and presence of spinal pain. Abnormal MRI findings and speed of onset of disease were significantly associated with survival. For the 32 cats with unremarkable MRI findings, only nine died due to spinal disease and, therefore, the median survival time (MST) was not reached (lower 95% confidence interval (CI)=970 days). For the 60 cats with abnormal MRI findings, 37 died due to their disease and the MST was 138 days (95% CI: 7-807).

Central nervous system infection with Staphylococcus intermedius secondary to retrobulbar abscessation in a dog.

In this report, we describe a case of retrobulbar abscessation in a dog that was initially diagnosed as masticatory myositis and treated with immunosuppressive doses of corticosteroids. Secondary bacterial infection of the central nervous system (CNS) occurred and was definitively diagnosed by the analysis and culture of the cerebrospinal fluid. This is the first time that retrobulbar infection has been definitively shown to result in secondary bacterial infection of the CNS in the dog and highlights the importance of ruling out infectious causes of retrobulbar disease before assuming and treating for an immune-mediated etiology.

Concurrent medical conditions and long-term outcome in dogs with nontraumatic intracranial hemorrhage.

Nontraumatic intracranial hemorrhage is bleeding originating from the brain or surrounding structures. It results from blood vessel rupture and may be primary or secondary in origin. The magnetic resonance imaging (MRI) characteristics of 75 dogs with nontraumatic intracranial hemorrhage were reviewed to determine signalment; intracranial compartment involved, size and number of lesions; type and prevalence of concurrent medical conditions; and long-term outcome. Hemorrhagic lesions were intraparenchymal (n = 72), subdural (n = 2) or intraventricular (n = 1). Thirty-three of 75 dogs had a concurrent medical condition. A concurrent condition was detected in 13 of 43 dogs with a single lesion ≥5 mm and included Angiostrongylus vasorum infection, intracranial lymphoma and meningioma. Of the 20 dogs with multiple lesions ≥5 mm, 7 had A. vasorum infection, 2 had hemangiosarcoma metastasis, 5 had suspected brain metastasis, and 1 was septicemic. Of the 12 dogs with multiple lesions, 2 had hyperadrenocorticism, 2 had chronic kidney disease, and 1 had hypothyroidism. Of these five dogs, all were hypertensive and four died within 12 months. No dog had a single lesion <5 mm. Long-term outcome was favorable in 26 of 43 dogs with single lesions ≥5 mm, 6 of 20 dogs with multiple lesions ≥5 mm, and 8 of 12 dogs with multiple lesions <5 mm. A. vasorum infection was the most common concurrent condition in dogs with nontraumatic intracranial hemorrhage (16/75), with an excellent outcome in 14 of 16 dogs. Prognosis in nontraumatic intracranial hemorrhage is reported in terms of concurrent medical conditions and the number and size of lesions.

Use of transsplenic injection of agitated saline and heparinized blood for the ultrasonographic diagnosis of macroscopic portosystemic shunts in dogs.

We describe the use of ultrasonography-guided percutaneous splenic injection of agitated saline and heparinized blood for the diagnosis of portosystemic shunts (PSS) in 34 dogs. Agitated saline mixed with 1 ml of heparinized autologous blood was injected into the spleen of 34 sedated dogs under sonographic guidance. The transducer was then sequentially repositioned to visualize the portal vein, the caudal vena cava, and the right atrium through different acoustic windows. It was possible to differentiate between intrahepatic and extrahepatic shunts depending on the entry point of the microbubbles into the caudal vena cava. Portoazygos shunts and portocaval shunts could be differentiated based on the presence of microbubbles in the caudal vena cava and/or the right atrium. In one dog, collateral circulation due to portal hypertension was identified. In dogs with a single extrahepatic shunt, the microbubbles helped identify the shunting vessel. The technique was also used postoperatively to assess the efficacy of shunt closure. All abnormal vessels were confirmed by exploratory laparotomy or with ultrasonographic identification of the shunting vessel. Ultrasound-guided transsplenic injection of agitated saline with heparinized blood should be considered as a valuable technique for the diagnosis of PSS; it is easy to perform, safe, and the results are easily reproducible.

Imaging diagnosis--celiac artery pseudoaneurysm associated with a migrating grass awn.

The ultrasound and computed tomography findings of a retroperitoneal pseudoaneurysm associated with a grass awn are described in a 10-month-old dog. Ultrasound was used to localize the lesion and surrounding reaction as well as to determine its relationship with the celiac artery, but inadequate Doppler settings hindered the diagnosis of its vascular nature. Dual phase CT enabled further characterization, particularly its close relationship with the major retroperitoneal vessels. The imaging examination was fundamental in recommending nonsurgical therapy. The dog died as a consequence of the rupture of this pseudoaneurysm. A grass awn was confirmed.

Ultrasonographic appearance of the intravascular transit of agitated saline in normal dogs following ultrasound guided percutaneous splenic injection.

Portosystemic shunts (PSSs) allow portal blood to bypass the liver and enter the systemic circulation. Definitive diagnosis requires surgical identification, positive contrast portography, ultrasonography, or scintigraphy. This study was designed as a preliminary step to developing an alternative/adjuvant protocol to these imaging modalities. The main goals were to establish a technique for ultrasound-guided percutaneous trans-splenic injection of agitated saline, to evaluate the feasibility of performing the test to explore the postsplenic portal vasculature highlighted by the microbubbles, and to ascertain whether agitated saline microbubbles cross the sinusoidal barrier. Agitated saline was injected into the spleen of 20 healthy sedated dogs under sonographic guidance. The transducer was then repositioned to visualize the portal vein, the caudal vena cava, and the right atrium through different acoustic windows. Satisfactory results were achieved in all dogs. The microbubbles were visualized in all dogs as small intense echo signals within the portal vein at the level of the porta hepatis immediately after injection. In 18 out of 20 dogs, the echogenic signal of the microbubbles disappeared immediately once within the hepatic parenchyma, whereas in two dogs, the echoes from the microbubbles lasted for several seconds within the intrahepatic portal vasculature. The absence of microbubbles beyond the sinusoidal barrier in all of the healthy dogs included in this study makes trans-splenic injection of agitated saline a candidate as an adjuvant technique for the diagnosis of PSS, being easy to perform and repeat, as well as safe and technically feasible.

Ultrasonography of the medial iliac lymph nodes in the dog.

Sixty-one medial iliac lymph nodes of 38 different dogs (eight with adenocarcinoma of the apocrine glands of the anal sac, 13 with multicentric lymphoma, six with multicentric lymphoma but in clinical remission, and 11 control dogs) were evaluated to assess the ability of ultrasound to identify and interrogate these lymph nodes across the different groups and to differentiate these groups using different sonographic parameters. Ultrasound proved to be useful to assess canine medial iliac lymph nodes. An increase in size or number of detected lymph nodes or finding rounder or heterogeneous lymph nodes could differentiate lymph nodes of dogs of the control group from lymph nodes of dogs with lymphoma or an adenocarcinoma of the apocrine glands of the anal sac. Subcategories of malignancy could not be differentiated. More studies need to be performed, both with patients with reactive lymph nodes and also focusing on other canine superficial lymph nodes, before generalizing the results of this study to other areas or diseases.

Magnetic resonance imaging of the presumed normal canine adrenal glands.

Forty-three dogs without evidence of endocrine disease that underwent spinal or abdominal magnetic resonance imaging (MRI) for clinical reasons were studied. Because the procedures were not optimized for inclusion of the adrenal glands, they were not always visible in all planes. Eighty-five of the 86 adrenal glands were seen and only the left gland in a 6-month-old Irish wolfhound could not be found. The right adrenal gland lay cranial to the left in all of the animals in which both glands were seen. The best landmarks for localization of the glands were vascular; both adrenal glands were always cranial to the ipsilateral renal vessels and in the region of the celiac and cranial mesenteric arteries. Various measurements were made on all the available scan planes. In some dogs the whole adrenal gland was difficult to visualize clearly, and this hindered the measuring process, especially when the right adrenal gland was in close contact with the caudal vena cava. The adrenal glands were mainly linear in shape but also had a variable degree of modification of their poles, especially the cranial pole of the right adrenal gland, which tended to be consistently wider and to present different shapes (rounded, arrowhead, inverted P, hook-shaped, triangular, or dome-shaped). Two main patterns of signal intensity were seen on fast spin echo (FSE) sequences (T2-weighted, T1-weighted, and T1-weighted after administration of a paramagnetic contrast medium): homogeneous and hypointense to surroundings or a corticomedullary type pattern with a hyperintense central area surrounded by a hypointense rim of tissue. The outline of the left adrenal gland was always very clear. The clarity of outline of the right adrenal gland was more variable, especially if it was in contact with the liver or the caudal vena cava. It was felt that the amount of retroperitoneal fat was not as important as stated in the human literature for visualization of the adrenal glands and that with an appropriate selection of scan planes and pulse sequences good assessment of the adrenal glands can be performed with MRI in canine patients.