Inés Carrera

Use of magnetic resonance imaging for morphometric analysis of the caudal cranial fossa in Cavalier King Charles Spaniels

OBJECTIVEnTo perform morphometric analysis of the caudal cranial fossa in Cavalier King Charles Spaniels (CKCSs), to assess the relationship between caudal fossa dimensions and the frequency of magnetic resonance imaging (MRI) features of occipital abnormalities in CKCSs (with and without syringomyelia), and to compare caudal cranial fossa measurements in CKCSs with measurements of 2 groups of mesaticephalic dogs.nnnANIMALSn70 CKCSs and 80 mesaticephalic (control) dogs.nnnPROCEDURESnDogs were placed into 4 groups as follows: Labrador Retrievers (n = 40), spaniel-type dogs (40; English Springer Spaniels and Cocker Spaniels), CKCSs with syringomyelia (55), and CKCSs without syringomyelia (15). Multiple morphometric measurements (linear, angular, and area) were obtained from cranial midsagittalT2-weighted magnetic resonance images including the brain and cervical portion of the spinal cord. Several specific MRI findings were also recorded for CKCSs that appeared to affect the occipital bone and cervicomedullary junction.nnnRESULTSnNo significant difference was identified among breeds in control groups and between sexes in any of the groups for all morphometric measurements. Significant differences were identified in CKCSs, compared with mesaticephalic dogs, in the area of the caudal cranial fossa and for several linear measurements that reflected the length of the ventral aspect of the occipital bone. These differences were greater in CKCSs with syringomyelia. All CKCSs had abnormalities in occipital bone shape.nnnCONCLUSIONS AND CLINICAL RELEVANCEnCKCSs had a shallower caudal cranial fossa and abnormalities of the occipital bone, compared with those of mesaticephalic dogs. These changes were more severe in CKCSs with syringomyelia.

Computed Tomographic Features of Incomplete Ossification of the Canine Humeral Condyle

OBJECTIVESnTo describe computed tomographic (CT) features of canine elbows with incomplete ossification of the humeral condyle (IOHC) and investigate co-existing incongruence in the elbow joint.nnnSTUDY DESIGNnCase control study.nnnANIMALSnDogs with IOHC (n=20; 38 elbows) and 25 normal elbows.nnnMETHODSnElbows with IOHC and normal elbows were assessed by CT. Standardized dorsal and sagittal reconstructions were created at 3 levels using image analysis software to obtain single measurements of the humero-radial and humero-ulnar joint spaces. On dorsal plane reconstructions, joint space measurements were obtained at the center point of the humero-radial and humero-ulnar articulations. Joint incongruity was defined as the difference between the humero-radial and the humero-ulnar joint spaces.nnnRESULTSnNineteen dogs (95%), all Spaniel breeds, had either bilateral IOHC demonstrable as a saw-toothed intercondylar complete or incomplete hypoattenuating defect with hyperattenuating margins, or IOHC with contralateral humeral condylar fracture (HCF). Joint incongruity values for IOHC were compared with those of normal elbows. Significant differences were noted at the levels of the medial coronoid apex (P<.0001) and base (P<.004) indicative of humero-ulnar incongruence. Evidence of medial coronoid disease in 10 elbows (26%) and degenerative joint disease in 30 elbows (79%) was also found.nnnCONCLUSIONSnPresence of elbow incongruence may be an underlying factor in failure of ossification centers to fuse leading to IOHC.nnnCLINICAL RELEVANCEnIOHC is clearly defined by CT, and it should be considered in larger Spaniel breeds, with a chronic forelimb lameness or HCF.

Radiographic analysis of trochlear notch sclerosis in the diagnosis of osteoarthritis secondary to medial coronoid disease.

Trochlear notch sclerosis (TNS) as assessed by radiography has been shown to be increased in elbow dysplasia (ED) associated medial coronoid process disease (MCD). The aims of this study were to investigate whether two defined radiographic tests evaluating TNS would increase the sensitivity of detecting osteoarthritis secondary to MCD, and to assess whether there was a correlation between increasing TNS with severity of MCD. Sixty-one dogs with MCD (121 elbows) were selected from the imaging database. The controls were nine cadavers (18 disease-free elbows). Standard International Elbow Working Group radiographs and CT scans were taken of each elbow. Plain radiographs were analysed using various assessments: osteophyte grade (0-3), coronoid grade (0-3), TNS descriptive grade (0-3) and TNS ratio. The TNS ratio was calculated from the depth of ulnar sclerosis at the level of the disto-cranial margin of the humeral condyles divided by the cranio-caudal ulna depth. The TNS descriptive assessment and ratio both increased the overall sensitivity of diagnosing osteoarthritis secondary to MCD above the other radiographic tests. The sensitivity of the TNS ratio at <0.3 mm was 91%-96% and the TNS descriptive assessment was 77%-96%. Radiographic TNS significantly increased with increasing severity of coronoid disease grade as evaluated by CT p < 0.01. The finding that TNS increases the sensitivity of diagnosing osteoarthritis secondary to MCD is valuable to those that have neither a CT scanner nor arthroscopy readily available. The assessments described in this study are easy to apply and do not require any sophisticated technology in order to detect sclerosis.

In vivo proton magnetic resonance spectroscopy for the evaluation of hepatic encephalopathy in dogs

OBJECTIVEnTo investigate clinical use of proton magnetic resonance spectroscopy ((1)H MRS) and to compare metabolic brain bioprofiles of dogs with and without hepatic encephalopathy.nnnANIMALSn6 dogs with hepatic encephalopathy and 12 control dogs.nnnPROCEDURESnConventional MRI and single-voxel (1)H MRS were performed with a 3-T magnet. Images for routine MRI planes and sequences were obtained. Single-voxel (1)H MRS was performed with a point-resolved sequence with a short echo time (35 milliseconds) and voxel of interest placement at the level of the basal ganglia. Metabolites of interest included the glutamine-glutamate complex (sum quantification of glutamate and glutamine), myoinositol, N-acetyl aspartate, total choline, and creatine. Data were analyzed with postprocessing fitting algorithm software, and metabolite concentration relative to water and ratios with creatine as the reference metabolite were calculated.nnnRESULTSnCompared with control dogs, dogs with hepatic encephalopathy had specific changes, which included significantly higher concentration relative to water of the glutamine-glutamate complex and significantly lower concentration of myoinositol. Choline and N-acetyl aspartate concentrations were also slightly lower in dogs with hepatic encephalopathy than in control dogs. No differences in creatine concentration were detected between groups.nnnCONCLUSIONS AND CLINICAL RELEVANCEn(1)H MRS aided in the diagnosis of hepatic encephalopathy in dogs, and findings supported the assumption that ammonia is a neurotoxin that manifests via glutamine-glutamate complex derangements. Use of (1)H MRS may provide clinically relevant information in patients with subclinical hepatic encephalopathy, equivocal results of bile acids tests, and equivocal ammonia concentrations or may be helpful in monitoring efficacy of medical management.

Regional metabolite concentrations in the brain of healthy dogs measured by use of short echo time, single voxel proton magnetic resonance spectroscopy at 3.0 Tesla

OBJECTIVEnTo investigate regional differences of relative metabolite concentrations in the brain of healthy dogs with short echo time, single voxel proton magnetic resonance spectroscopy ((1)H MRS) at 3.0 T.nnnANIMALSn10 Beagles.nnnPROCEDURESnShort echo time, single voxel (1)H MRS was performed at the level of the right and left basal ganglia, right and left thalamus, right and left parietal lobes, occipital lobe, and cerebellum. Data were analyzed with an automated fitting method (linear combination model). Metabolite concentrations relative to water content were obtained, including N-acetyl aspartate, total choline, creatine, myoinositol, the sum of glutamine and glutamate (glutamine-glutamate complex), and glutathione. Metabolite ratios with creatine as the reference metabolite were calculated. Concentration differences between right and left hemispheres and sexes were evaluated with a Wilcoxon signed rank test and among various regions of the brain with an independent t test and 1-way ANOVA.nnnRESULTSnNo significant differences were detected between sexes and right and left hemispheres. All metabolites, except the glutamine-glutamate complex and glutathione, had regional concentrations that differed significantly. The creatine concentration was highest in the basal ganglia and cerebellum and lowest in the parietal lobes. The N-acetyl aspartate concentration was highest in the parietal lobes and lowest in the cerebellum. Total choline concentration was highest in the basal ganglia and lowest in the occipital lobe.nnnCONCLUSIONS AND CLINICAL RELEVANCEnMetabolite concentrations differed among brain parenchymal regions in healthy dogs. This study may provide reference values for clinical and research studies involving (1)H MRS performed at 3.0 T.

Computed tomographic features of feline nasopharyngeal polyps.

The computed tomographic (CT) findings of histopathologically confirmed nasopharyngeal polyps are described in 13 cats. Most polyps were mildly hypoattenuating to adjacent muscles and isoattenuating to soft-tissue (n= 13), homogeneous (n = 12) and with ill-defined borders (n = 10) on precontrast images. After contrast medium administration, the polyps were homogeneous (n = 11), with well-defined borders (n = 13), oval (n = 13), and had rim enhancement (n = 13). Nasopharyngeal polyps were pedunculated in 11 cats with a stalk-like structure connecting the polyp through the auditory tube to an affected tympanic bulla. All cats had at least one tympanic bulla severely affected, with CT images identifying: (1) complete (n = 12) or partial (n = 1) obliteration of either the dorsal or ventral compartments with soft-tissue attenuating material; (2) pathologic expansion (n = 13) with wall thickening (n = 10) that was asymmetric in nine cats; and (3) identification of a polyp-associated stalk-like structure (n = 11). Nine cats had unilateral tympanic bulla disease ipsilateral to the polyp, and four cats had bilateral tympanic bulla disease, most severe ipsilateral to the polyp with milder contralateral pathologic changes. Two cats had minimal osteolysis of the tympanic bulla. Enlargement of the medial retropharyngeal lymph node was seen commonly (n = 8), and in all cats it was ipsilateral to the most affected tympanic bulla. One cat had bilateral lymphadenopathy. CT is an excellent imaging tool for the supportive diagnosis of nasopharyngeal polyps in cats. CT findings of a well-defined mass with strong rim enhancement, mass-associated stalk-like structure, and asymmetric tympanic bulla wall thickening with pathologic expansion of the tympanic bullae are highly indicative of an inflammatory polyp.

Effects of hypotension and/or hypocapnia during sevoflurane anesthesia on perfusion and metabolites in the developing brain of piglets—a blinded randomized study

Hypotension (HT) and/or hypocapnia (HC) are frequent complications occurring during pediatric anesthesia and may cause cerebral injury in the developing brain.

Evaluation of intracranial neoplasia and noninfectious meningoencephalitis in dogs by use of short echo time, single voxel proton magnetic resonance spectroscopy at 3.0 Tesla

OBJECTIVE To investigate metabolite concentrations of the brains of dogs with intracranial neoplasia or noninfectious meningoencephalitis by use of short echo time, single voxel proton magnetic resonance spectroscopy ((1)H MRS) at 3.0 T. ANIMALS 29 dogs with intracranial lesions (14 with neoplasia [3 oligodendromas, 3 glioblastomas multiformes, 3 astrocytomas, 2 lymphomas, and 3 meningiomas] and 15 is with noninfectious meningoencephalitis) and 10 healthy control dogs. PROCEDURES Short echo time, single voxel (1)H-MRS at 3.0 T was performed on neoplastic and noninfectious inflammatory intracranial lesions identified with conventional MRI. Metabolites of interest included N-acetyl aspartate (NAA), total choline, creatine, myoinositol, the glutamine-glutamate complex (Glx), glutathione, taurine, lactate, and lipids. Data were analyzed with postprocessing fitting algorithm software. Metabolite concentrations relative to brain water content were calculated and compared with results for the healthy control dogs, which had been previously evaluated with the same (1)H MRS technique. RESULTS NAA, creatine, and Glx concentrations were reduced in the brains of dogs with neoplasia and noninfectious meningoencephalitis, whereas choline concentration was increased. Concentrations of these metabolites differed significantly between dogs with neoplasia and dogs with noninfectious meningoencephalitis. Concentrations of NAA, creatine, and Glx were significantly lower in dogs with neoplasia, whereas the concentration of choline was significantly higher in dogs with neoplasia. Lipids were predominantly found in dogs with high-grade intra-axial neoplasia, meningioma, and necrotizing meningoencephalitis. A high concentration of taurine was found in 10 of 15 dogs with noninfectious meningoencephalitis. CONCLUSIONS AND CLINICAL RELEVANCE (1)H MRS provided additional metabolic information about intracranial neoplasia and noninfectious meningoencephalitis in dogs.

Short- and Long-Term Outcomes After Arthroscopic Treatment of Young Large Breed Dogs With Medial Compartment Disease of the Elbow

OBJECTIVESnTo report short- and long-term outcomes after arthroscopic treatment in young large breed dogs affected by medial coronoid process disease (MCPD) and identify variables affecting outcome.nnnSTUDY DESIGNnProspective observational case series.nnnANIMALSnLarge breed dogs <3 years old (nu2009=u200915; 23 elbows).nnnMETHODSnMCPD was confirmed by radiography, computed tomography, and arthroscopy. Dogs were treated by arthroscopy. Variables recorded at time of treatment included radioulnar incongruity (RUI) and degree of cartilage erosion. Variables recorded before, 6 weeks, and ≥23 months after surgery included radiographic score for osteoarthritis, trochlear notch sclerosis, muscle circumference, range of motion (ROM), and the load distribution of vertical ground reaction forces between thoracic and pelvic limbs.nnnRESULTSnA greater load distribution to the pelvic limbs was identified preoperatively in dogs with RUI than in dogs with congruent elbows. Load distribution was not significantly improved at 6 weeks compared with preoperatively. Muscle circumference and vertical impulse distributions were improved at long-term evaluation despite an increased osteoarthritis score. This improvement was more obvious in dogs with RUI or a high degree of cartilage erosion at initial presentation.nnnCONCLUSIONnSome evidence of improvement in long-term function was found in dogs with MCPD after arthroscopic treatment. RUI and cartilage erosion at the time of diagnosis were associated with more lameness preoperatively but did not affect the final gait assessment or osteoarthritis score in this small cohort.

A newly designed radiation therapy protocol in combination with prednisolone as treatment for meningoencephalitis of unknown origin in dogs: a prospective pilot study introducing magnetic resonance spectroscopy as monitor tool

BackgroundA plethora of treatment options have been described for canine meningoencephalitis of unknown origin (MUO), yet a gold standard has not been established. The aim of this prospective pilot study was to document the effect of a newly designed 30 Gray (Gy) radiation therapy (RT) protocol plus corticosteroids as treatment for focal and multifocal MUO, to monitor clinical and imaging changes during the course of the disease with conventional magnetic resonance imaging (MRI) and proton MR Spectroscopy (H-1 MRS) and to detect the occurrence of radiation related side effects.ResultsSix dogs (3 with focal and 3 with multifocal lesions) were included in the study. The RT protocol used consisted of 30 Gy in 10 fractions. The neurological status of all six dogs improved during RT, with 3 of 6 cases returning to a normal condition. One dog was euthanized early during follow-up (<3 weeks after end of RT). Three month follow up MRI was normal in one dog and improved in 3 dogs and H-1 MRS normalized in 4. In the dog without improvement of the MRI lesions, the N-acetyl aspartate continued to decrease, while choline and creatine concentrations remained stable during that time. This dog was euthanized 18 month after the end of RT due to relapse. One dog was lost to follow up 12 month after completion of RT. The other 3 dogs are still alive at the time of writing.ConclusionsRT with 30 Gy in 10 fractions can provide an additional option for anti-inflammatory treatment of focal and multifocal MUO. The protocol used for treatment monitoring was feasible while no side effects of RT could be observed during the follow up period. Moreover, H-1 MRS could represent a new and non-invasive tool to control the progression of the disease during the treatment course.