T2W Hyperintense Research Articles

Magnetic resonance imaging findings in dogs with steroid-responsive meningitis-arteritis in the UK and their clinical significance: 53 cases (2013-2021).

To describe the MRI findings in a UK referral population of dogs with steroid-responsive meningitis-arteritis and to determine if they were associated with any specific clinical features or outcomes. We performed a multi-centre retrospective case series of dogs diagnosed with steroid-responsive meningitis-arteritis in the UK that underwent MRI. Blinded consensus review of the MRI studies was performed and the findings described. The presence or absence of specific MRI abnormalities were analysed for significant associations with presenting signs, results of investigations or case outcomes. Fifty-three dogs were included. The most common MRI findings were paravertebral muscle changes (30/53; 56.6%), meningeal contrast enhancement (13/41; 31.7%) and spinal cord parenchymal T2-W hyperintensity (15/53; 28.3%). Haemorrhage was observed in five of 53 (9.4%) cases - three intradural-extramedullary, one intramedullary and one extradural. Following binary logistic regressions, T2-W spinal cord parenchymal hyperintensity had a significant positive association with paresis/paralysis (odds ratio 14.86, 95% confidence interval 1.42 to 154.99) as did haemorrhage (odds ratio 16.12, confidence interval 2.05 to 126.73). Fifty-two (98.1%) dogs survived to discharge. Relapse occurred in nine of 29 (31.0%) dogs with sufficient follow-up, and no MRI finding had a significant relationship with its occurrence. Magnetic resonance imaging findings for steroid-responsive meningitis-arteritis can be severe and extensive, as can the clinical presentation. The presence of paresis/paralysis should raise concern for haemorrhage, though most dogs still have a good prognosis.

External auditory canal atresia affecting the horizontal canal of a 2‐year‐old Labrador Retriever dog

AbstractA 2‐year‐old, female neutered, Labrador Retriever dog was presented with left otalgia. Otoscopic examination revealed a blind ending left external ear canal. Magnetic resonance imaging confirmed an abrupt narrowing of the lateral aspect of the horizontal canal, medial to which the remaining horizontal ear canal and middle ear cavities contained well‐delineated, homogenous, T2w, fluid‐attenuated inversion recovery and T1w hyperintense, non‐contrast enhancing material. A diagnosis of external auditory canal atresia was made based on the imaging findings. Considering the patient's age and absence of preceding trauma, a congenital cause was considered most likely. Surgical treatment by way of a total ear canal ablation with lateral bulla osteotomy was performed. At the re‐check appointment, the surgical site had healed well and there were no associated complications noted; a telephone call with the owner 5 months later documented no clinical concerns.

Potential thresholds of critically increased cardiac-related spinal cord motion in degenerative cervical myelopathy.

New diagnostic techniques are a substantial research focus in degenerative cervical myelopathy (DCM). This cross-sectional study determined the significance of cardiac-related spinal cord motion and the extent of spinal stenosis as indicators of mechanical strain on the cord. Eighty-four DCM patients underwent MRI/clinical assessments and were classified as MRI+ [T2-weighted (T2w) hyperintense lesion in MRI] or MRI- (no T2w-hyperintense lesion). Cord motion (displacement assessed by phase-contrast MRI) and spinal stenosis [adapted spinal canal occupation ratio (aSCOR)] were related to neurological (sensory/motor) and neurophysiological readouts [contact heat evoked potentials (CHEPs)] by receiver operating characteristic (ROC) analysis. MRI+ patients (N = 31; 36.9%) were more impaired compared to MRI- patients (N = 53; 63.1%) based on the modified Japanese Orthopedic Association (mJOA) subscores for upper {MRI+ [median (Interquartile range)]: 4 (4-5); MRI-: 5 (5-5); p < 0.01} and lower extremity [MRI+: 6 (6-7); MRI-: 7 (6-7); p = 0.03] motor dysfunction and the monofilament score [MRI+: 21 (18-23); MRI-: 24 (22-24); p < 0.01]. Both patient groups showed similar extent of cord motion and stenosis. Only in the MRI- group displacement identified patients with pathologic assessments [trunk/lower extremity pin prick score (T/LEPP): AUC = 0.67, p = 0.03; CHEPs: AUC = 0.73, p = 0.01]. Cord motion thresholds: T/LEPP: 1.67 mm (sensitivity 84.6%, specificity 52.5%); CHEPs: 1.96 mm (sensitivity 83.3%, specificity 65.6%). The aSCOR failed to show any relation to the clinical assessments. These findings affirm cord motion measurements as a promising additional biomarker to improve the clinical workup and to enable timely surgical treatment particularly in MRI- DCM patients. www.clinicaltrials.gov, NCT02170155.

A Case Report of Spinal Cord Edema and Cervical Spondylosis Masquerading as Chronic Inflammatory Demyelinating Polyneuropathy (CIDP)

A 64-year-old previously-healthy male presented with 2-year history of progressive neurological symptoms of numbness and muscle weakness involving all 4 limbs. There was gait disturbance, urinary and fecal incontinence. On examination, the left upper limb had normal tone, diminished deep tendon reflexes and power of 4/5 with wasting both in proximal and distal muscles. There were reduced pinprick pain and temperature sensations below the elbow bilaterally with intact vibration and proprioception. Both lower limbs had increased tone, diminished deep tendon reflexes, power of 3/5 with wasting both in proximal and distal muscles with unequivocal plantar reflex bilaterally. There were reduced pinprick pain and temperature sensations below the knee on right and below the ankle on left with intact vibration and proprioception. Nerve Conduction Studies (NCS) were done which showed axonal type of denervation in all limbs. MRI scan of Cervical Spine showed T2W hyperintense signals and narrowing of spinal canal from C3 to C7 region. The final diagnosis was spinal cord edema in the cervical region and cervical spondylosis causing spinal cord compression. Keywords: Chronic Inflammatory Demyelinating Polyneuropathy (CIDP), Spinal cord edema, Cervical spondylosis, Nerve Conduction Studies (NCS), MRI scan, Case report.

Diffuse paediatric-type high-grade glioma, H3-wildtype and IDH-wildtype: case series of a new entity.

Diffuse paediatric-type high-grade glioma, H3-wildtype and IDH-wildtype (pHGG) is a rare and aggressive brain tumor characterized by a specific DNA methylation profile. It was recently introduced in the 5th World Health Organization classification of central nervous system tumors of 2021. Clinical data on this tumor is scarce. This is a case series, which presents the first clinical experience with this entity. We compiled a retrospective case series on pHGG patients treated between 2015 and 2022 at our institution. Data collected include patients' clinical course, surgical procedure, histopathology, genome-wide DNA methylation analysis, imaging and adjuvant therapy. Eight pHGG were identified, ranging in age from 8 to 71years. On MRI tumors presented with an unspecific intensity profile, T1w hypo- to isointense and T2w hyperintense, with inhomogeneous contrast enhancement, often with rim enhancement. Three patients died of the disease, with overall survival of 19, 28 and 30months. Four patients were alive at the time of the last follow-up, 4, 5, 6 and 79months after the initial surgery. One patient was lost to follow-up. Findings indicate that pHGG prevalence might be underestimated in the elderly population.

Bagel sign in neuro Behçet's disease myelitis: neuroimages.

Neuro-Behçet's disease (NBD) is a chronic heterogenous autoimmune disorder. It may involve central or pripheral nervous system but rarely shows spinal cord involvement (SCI). Bagel Sign is a unique sign of SCI due to NBD. It is a central T2W hyperintense lesion with a hypointense core on axial magnetic resonance imaging (MRI). This sign may be a complete or an incomplete ring with or without post-contrast enhancement. Here we report a patient with NBD whose primary presentaion was transverse myelitis. A 14-year-old patient was admitted due to triparesis and urinary retention. He had T2W hyperintensities from the left basal ganglion down to the T10 level. A similar anteromedial spot has been described in anterior spinal cord infarction which favors an ischemic pathogenesis for NBD. To our knowledge this is the first report of Bagel Sign and longitudinally extensive transverse myelitis with gray matter involvement.

High‐field magnetic resonance imaging findings in a young dog with septic arthritis of the shoulder joint

AbstractA 7‐month‐old, female Rough Collie with a history of diagnosis and treatment for steroid‐responsive meningitis‐arteritis was presented with a history of recurrent fever and lethargy and progressive lameness. Magnetic resonance imaging revealed a large fluid intensity lesion (T2W hyperintense to muscle, T1W hypointense and in both sequences isointense to joint fluid) centred on the medial aspect of the right shoulder joint with outpouching into the surrounding muscle. On post‐contrast T1W images, there was extensive enhancement of the synovium and of the outpouching within the subscapularis muscle (centrally non‐enhancing consistent with abscessation, haemorrhage or necrosis). Bacteriological culture and sensitivity testing on fluid of the shoulder joint and lesion revealed monoculture of multidrug‐resistant Pseudomonas aeruginosa. This case report illustrates the value of magnetic resonance imaging in the diagnosis of musculoskeletal pathology.

Cerebral White Matter Demyelination in Vitamin B12 Deficiency: A Case Report

Vitamin B12 deficiency has been classically associated with subacute combined degeneration of the cord. It can be readily recognized on magnetic resonance imaging as T2W hyperintensity of the dorsal column. Cerebral changes are being increasingly notified, especially in the elderly population. The authors report the case of a 33-year-old patient and describe the imaging characteristics.

A different indication of pisphosphonates: Bone marrow edema

Abstract Introduction Bone marrow edema (BME) is an uncommonly diagnosed, reversible condition most often affecting the hip of middle-aged men. BME is characterized clinically by the onset of disabling bone pain, usually at a single skeletal site, generally in the lower limbs and most often the hip. Diagnosis is often delayed. The increased bone turnover and low bone mineral density may indicate a potential role for bisphosphonate therapy in BME. There is some evidence of the successful use of intravenous bisphosphonates in the treatment of BME of the hip. We aimed to present two cases of BME that were successfully treated with bisphosphonates. Clinical Case 1: A 41-year-old male patient presented with left inguinal pain. His past medical history was unremarkable. The visual analog scale (VAS) was 8–9. On physical examination, there was a limited range of motion (ROM) on the left hip. Laboratory results were within normal limits. Non-contrast MRI revealed signal intensity changes consistent with BME in the left femoral head and neck of the femur, which was hypointense in T1W sections and hyperintense in T2W sections. With assisted mobilization, 3 mg IV ibandronic acid, calcium and vitamin D replacement was started. Pain control was achieved one week after bisphosphonate infusion. Complete resolution of bone marrow edema was seen in the MRI taken 2 months later (Figure 1). Bisphosphonate treatment with alendronate was completed for one year. Clinical Case 2: A 59-year-old male patient presented with right hip pain that limits his walking. He was diagnosed with BME and avascular necrosis as a result of clinical and radiological evaluation in the center he applied and he underwent a right femoral core decompression operation. He was evaluated in our clinic due to ongoing pain and limitation of movement 5 months after the operation. On physical examination, there was limited ROM on right hip. All the results of laboratory tests were normal. MRI revealed signal changes consistent with bone marrow edema in the right femoral head and neck of the femur, which was hypointense in T1W sections and hyperintense in T2W sections. With assisted mobilization, 3 mg IV ibandronic acid, calcium and vitamin D replacement was started. Pain control was achieved 10 days after bisphosphonate infusion, and he returned to working life 1 month later. Complete resolution of the BME was observed in MRI performed 10 weeks later. Completion of the bisphosphonate treatment with alendronate for 1 year was planned. Conclusion The hip is the most frequently involved joint, with diffuse BME pattern in the femoral head and intertrochanteric region observed on MRI. BME may be a precursor to avascular necrosis when the diagnosis is delayed or the treatment is not well managed. Therefore, optimal timing of medical intervention is very important. Treatment with bisphosphonates is an effective and safe treatment. Additionally, providing early mobilization may prevent the risk of avascular necrosis and the workforce loss.

Quantitative susceptibility mapping for differentiating multiple sclerosis from cerebral small vessel disease

Background and Purpose: With the increasing prevalence of cerebrovascular risk factors in young adults, accurate differentiation of multiple sclerosis (MS) from cerebral small vessel disease (SVD) remains challenging because of the significant overlap in the appearance of white matter lesions on conventional magnetic resonance (MR) images. The purpose of this study was to use quantitative susceptibility mapping (QSM) to differentiate patients with MS from patients with SVD. Materials and Methods: Thirty-two patients with relapsing-remitting MS and 40 patients with SVD were selected in this institution review board-approved retrospective study. All patient examinations included QSM and T2-weighted FLAIR (T2w). All T2w hyperintense lesions were analyzed on QSM for susceptibility relative to normal-appearing white matter and were evaluated for the presence of hyperintense rims and the central vein sign. Receiver operating characteristic (ROC) curve analysis was performed to assess the diagnostic accuracy of differentiating MS patients from SVD patients. Results: The mean susceptibility value of SVD lesions was significantly lower than MS lesions (2.31 ± 9.68 ppb vs. 27.77 ± 20.27 ppb, p &lt; 0.001). Of MS patients and MS lesions, 68.8% and 22.2% had hyperintense rims on QSM, respectively. Of MS patients and MS lesions, 75% and 37.6% had a central vein sign on QSM, respectively. Lesion susceptibility values allowed accurate differentiation MS from SVD with an area under the ROC curve (AUC) = 0.848 for lesion differentiation, AUC = 0.999 for patient differentiation, and an optimal cut-off susceptibility value of 14.88 ppb. Conclusions: Magnetic susceptibility measured using QSM allows accurate differentiation of MS patients from SVD patients.

Ischemic stroke can have a T1w hyperintense appearance in absence of intralesional hemorrhage.

Magnetic resonance imaging (MRI) signal changes associated with ischemic stroke are typically described as T2w and FLAIR hyperintense, and T1w isointense lesions. Intralesional T1w hyperintensity is generally attributed to either a hemorrhagic stroke, or an ischemic stroke with hemorrhagic transition, and has an associated signal void on gradient echo (GE) sequences. Cases of ischemic stroke with T1w hyperintense signal in absence of associated signal void on GE sequences have been sporadically demonstrated in human stroke patients, as well as in dogs with experimentally induced ischemia of the middle cerebral artery. This multicenter retrospective descriptive study investigates the presence of T1w hyperintensity in canine stroke without associated signal void on GE sequences. High field (1.5 Tesla) MRI studies of 12 dogs with clinical presentation, MRI features, and cerebrospinal fluid results suggestive of non-hemorrhagic stroke were assessed. The time between the observed onset of clinical signs and MRI assessment was recorded. All 12 patients had an intralesional T1w hyperintense signal compared to gray and white matter, and absence of signal void on T2*w GE or SWI sequences. Intralesional T1w hyperintensities were either homogenously distributed throughout the entire lesion (6/12) or had a rim-like peripheral distribution (6/12). The mean time between the recorded onset of clinical signs and MRI assessment was 3 days; however, the age range of lesions with T1w hyperintense signal observed was 1–21days, suggesting that such signal intensities can be observed in acute, subacute, or chronic stages of ischemic stroke. Follow-up was recorded for 7/12 cases, all of which showed evidence of neurological improvement while in hospital, and survived to discharge. Correlation of the age and MRI appearance of lesions in this study with similar lesions observed in human and experimental studies suggests that these T1w hyperintensities are likely caused by partial tissue infarction or selective neuronal necrosis, providing an alternative differential for these T1w hyperintensities observed.

IMG-05 Imaging characteristics of CNS NB-FOXR2 – a retrospective and MULTI-INSTITUTIONAL DESCRIPTION OF 25 CASES

BACKGROUND: The CNS neuroblastoma with forkhead box R2 (CNS NB-FOXR2) activation is one of the new embryonal tumor entities in the WHO CNS tumor classification 2021. The data currently available suggest a comparably favourable outcome after craniospinal irradiation and chemotherapy. The entity is poorly characterized on imaging. We therefore aimed to describe imaging features in a multi-center patient cohort. MATERIAL AND METHODS: Molecularly and histologically confirmed CNS NB-FOXR2 tumors were retrospectively collected at six pediatric oncology centers. The imaging features on preoperative MRI and CT data were recorded by 8 experienced pediatric (neuro)radiologists in consensus. RESULTS: Twenty-five patients were identified (13 females). The majority of tumors were large at presentation (mean 115 ± SD 83 ml), showed mostly none or little perifocal edema, enhanced only partly, were often calcified and/or hemorrhagic, were always T2w hyperintense to gray matter, and often had cystic and/or necrotic components. The min. mean ADC values were relatively low (mean 687.8 ± SD 136.3 in 10-6mm2/s). The tumors originated never infratentorial and were never centered in the midline. Metastases were rare. CONCLUSIONS: For the first time, imaging characteristics of the recently described CNS NB-FOXR2 are described in a multi-center cohort. The results of this study may assist in diagnosing these tumors preoperatively. Collaborative pooling of cases is important to gain insight into typical imaging features of rare tumors, especially in view of the increasing molecular-driven subtyping.

Thinking Beyond Adenocarcinoma of Prostate: A Case Series of T2W Hyperintense Prostatic Lesions

The T2-weighted sequences form an integral part of multiparametric Magnetic Resonance Imaging (MRI) protocol performed for evaluation of the prostate. Most commonly encountered prostatic pathologies are adenocarcinoma and benign prostatic hyperplasia, which are mostly T2W hypointense and heterogeneously hypointense, respectively. Apart from prostatic cysts, only a small proportion of prostatic lesions demonstrate predominantly high signal intensity on T2-weighted sequences. Herein, the authors present three such cases with T2W hyperintense prostatic lesions. The first case (60-year-old male) was a prostatic abscess, which apart from T2W hyperintensity, showed central restricted diffusion and peripheral enhancement. The second case (40-year-old male) was a cystic lesion in left side of prostate, which was an ectopic ureterocele opening into the prostatic urethra with associated left renal agenesis. The third case (35-year-old male) was of a metastatic prostatic malignancy, which was a rare prostatic sarcoma. Radiologists should be cognizant of such conditions so as to enable them to make accurate diagnosis and guide appropriate patient management.

MRI Evaluation of Invasive Sinonasal Mucormycosis in Post COVID-19 Patients: A Retrospective Study

Introduction: Mucormycosis is also known as phycomycosis or zygomycosis, is caused by a saprophytic fungal infection. During the second wave of coronavirus disease-2019 (COVID- 19), secondary complication among clinically severe COVID-19 with or without diabetes was the involvement of the paranasal sinuses, rhino-orbitalocerebral, cutaneous, gastric and lungs by mucormycosis. The disease progresses rapidly within a few hours to days, causing cranial nerve palsies and intracranial spread of the disease. Early imaging is helpful in assessing the extent of the spread of the disease and complications and planning the treatment. Aim: The purpose of this study is to assess the distinct MRI findings in invasive sinonasal mucormycosis in post COVID-19 patients and also to describe the various patterns of extension. Materials and Methods: This retrospective study was carried out on post COVID patients with imaging features of invasive sinonasal mucormycosis in the rural population of Hoskote, Bangalore, who underwent MRI at MVJ Medical College and Research Hospital, Hoskote, Bangalore, India in a tertiary care center, between May 2021 to July 2021. A total of 20 patients met the inclusion criteria. The various imaging features of invasive sinonasal mucormycosis were evaluated and tabulated, along with a description of its extensions. All the data obtained from the study was compiled with Microsoft Excel (2019 version). Results: The study showed a male predominance with a mean age of 47.5 years. The most commonly involved sinus was the ethmoid sinus, seen in all 20 patients (100%), followed by a combination of the ethmoid and maxillary sinus 10 (50%). MRI showed T2W hyperintense mucosal thickening with hypointense contents within the involved sinuses in all cases, hypointensity along the turbinates and nasal septum and heterogeneous post contrast enhancement. The intraorbital extension was seen in 15 patients (75%), intracranial involvement in 4 patients (20%), bone involvement in 2 cases (10%) and pterygopalatine fossa involvement in 5 patients (25%), face involvement seen in 2 patients (10%). Conclusion: Magnetic Resonance Imaging (MRI) aids in a thorough evaluation of intracranial and soft tissue involvement, orbital, skull base invasion, perineural spread and vascular invasion. MRI demonstrates variable signal intensity depending on the sinus contents and variable enhancement patterns with a lack of enhancement due to tissue necrosis, an early finding of mucormycosis. Therefore, radiologists should be aware of the imaging findings and evaluation of the extensions, which can lead to early diagnosis and timely management, reducing the morbidity and mortality rates.

The sellar region as presenting theater for hematologic malignancies-A 17-year single-center experience.

Hematological neoplastic mass lesions of the sellar region are rare. We identified five cases of hematological malignancy with first presentation in the sellar region from our departmental database of 1,405 patients (0.36%) with sellar lesions diagnosed over the 17-year period (2005-2021). All patients were females (mean age 55.2 ± 3.4 years). One patient had multiple myeloma (MM), one patient had acute myeloid leukemia (AML), while three other patients had lymphoma (intravascular lymphoma (IVL, n = 1) or non-Hodgkin's lymphoma (NHL, n = 2). Most patients presented with ophthalmoplegia, and one patient with diabetes insipidus (DI), with short duration of symptoms (median 30 days). All patients had an elevated erythrocyte sedimentation rate and altered blood count, while patients with lymphoma had elevated lactate dehydrogenase (LDH). Sellar mass was demonstrated in three patients while the patient with IVL had an empty sella and in the AML patient posterior lobe T1W hyperintensity was lost. Two patients (IVL and NHL) presented with multiple anterior pituitary deficiencies and one patient (AML) had DI. All patients were treated with chemotherapy. Two patients responded well to treatment (one had reversed hypopituitarism), while three patients died. Differential diagnosis of sellar-parasellar pathology should include suspicion of hematological malignancy, particularly in patients with short duration of nonspecific symptoms, neurological signs (ophthalmoplegia), blood count alterations and LDH elevation, pituitary dysfunction and imaging features atypical for pituitary adenoma. Early diagnosis is crucial for timely initiation of hematological treatment aimed at inducing disease remission and partial or full recovery of pituitary function.

A study on clinical outcomes of Rathke's cleft cyst in patients managed conservatively.

The primary objective was to investigate the clinical presentation, hormonal dysfunction, imaging characteristics and natural history of RCCs that were managed conservatively. Secondary objective was to identify factors associated with cyst progression. A retrospective review of patients with the clinical diagnosis of RCC-identified from word search from radiology reports that were followed up from January 1999 to March 2019 was performed. The demographics, clinical data, radiological features and outcomes were reviewed and analyzed. 105 patients were identified with a median follow up of 6years. 68 patients (64.8%) were managed conservatively from diagnosis till last follow up while 37 patients (35.2%) underwent surgery, with 26 operated at time of diagnosis and 11 operated upon monitoring. For patients managed conservatively from diagnosis till last follow up, incidental finding was the most common presentation. 19.1% had either one or more axes of hormonal dysfunction, with hypogonadism and hypocortisolemia being the commonest ones. Imaging features were variable. 66.2% of patients had T2W hyperintensity on MRI. Pathognomonic feature of intracystic nodule was present in only 14.7% of patients. Among the 79 patients with repeated MRI imaging (68 from conservative group and 11 from surgical group), 32.9% of patients developed cyst progression while 67.1% had either static disease or regression in size of RCC. Median time to progression of cyst was 14months. Longer median follow up duration and presence of pituitary stalk displacement at presentation were associated with cyst progression. Only one patient developed new endocrine dysfunction. 2/3 of the RCCs had static disease or even regression in the size of the cyst. They rarely gave rise to additional endocrine dysfunction by adopting observant approach. Cyst progression was demonstrated in 1/3 of patients. Conservative treatment remained a reasonable treatment for patients without significant symptoms.

MRI radiomics to differentiate between low grade glioma and glioblastoma peritumoral region.

The peritumoral region (PTR) of glioblastoma (GBM) appears as a T2W-hyperintensity and is composed of microscopic tumor and edema. Infiltrative low grade glioma (LGG) comprises tumor cells that seem similar to GBM PTR on MRI. The work here explored if a radiomics-based approach can distinguish between the two groups (tumor and edema versus tumor alone). Patients with GBM and LGG imaged using a 1.5T MRI were included in the study. Image data from cases of GBM PTR, and LGG were manually segmented guided by T2W hyperintensity. A set of 91 first-order and texture features were determined from each of T1W-contrast, and T2W-FLAIR, diffusion-weighted imaging sequences. Applying filtration techniques, a total of 3822 features were obtained. Different feature reduction techniques were employed, and a subsequent model was constructed using four machine learning classifiers. Leave-one-out cross-validation was used to assess classifier performance. The analysis included 42 GBM and 36 LGG. The best performance was obtained using AdaBoost classifier using all the features with a sensitivity, specificity, accuracy, and area of curve (AUC) of 91%, 86%, 89%, and 0.96, respectively. Amongst the feature selection techniques, the recursive feature elimination technique had the best results, with an AUC ranging from 0.87 to 0.92. Evaluation with the F-test resulted in the most consistent feature selection with 3 T1W-contrast texture features chosen in over 90% of instances. Quantitative analysis of conventional MRI sequences can effectively demarcate GBM PTR from LGG, which is otherwise indistinguishable on visual estimation.

Association of neurologic signs with high-field MRI findings in 100 dogs with osseous-associated cervical spondylomyelopathy.

Although osseous-associated cervical spondylomyelopathy (OA-CSM) findings have been well described using magnetic resonance imaging (MRI), there are no large-scale published studies on the associations between dog size, age, high-field MRI and neurologic findings. Using a retrospective, observational study design, we aimed to investigate an association between neurologic and high-field MRI characteristics in OA-CSM. Records were reviewed for dogs diagnosed with OA-CSM using high-field MRI. One-hundred dogs were included: 73/100 (73%) were giant breeds, 27/100 (27%) large breeds. Mean and median ages were, respectively, 3.1 and 2 years (0.3-9.75 years), with 2.6 and 2 years for giant-breed; and 4.4 and 4 years for large-breed dogs. The majority of dogs were male (75%) with chronic presentation (89%), more than one site of spinal cord compression (78%) and foraminal stenosis (91%). Dogs with multiples sites of spinal cord compression were more likely to have severe spinal cord compression (p<0.001), severe foraminal stenosis (p<0.001) and ligamentum flavum/soft tissue proliferation (p=0.03) than those with a single compressive site. There was a weak correlation between neurologic grade and severity of spinal cord compression (r=0.27; p=0.007), number of affected sites (r=0.24; p=0.0183) and spinal cord T2W hyperintensity (r=0.24; p=0.0152). Intervertebral disc degeneration was seen in 80% of dogs. Age did not appear to have a prominent role in the manifestation of OA-CSM. This study showed that OA-CSM affects a sizeable proportion of young large-breed, in addition to giant-breed dogs.

MRI findings in a young dog with gliomatosis cerebri.

A 3-year-old male entire boxer presented with a 3-week history of lethargy, hyporexia, hypersalivation, low-head carriage, pelvic limb tremors and intermittent vestibular ataxia. Neurological examination revealed kyphosis, wide-based stance, an alternating head tilt, left leaning, bilateral positional ventral strabismus and intermittent vertical nystagmus. Exacerbation of neurological signs and increased extensor tone in all limbs were noticed after dorsal extension of the neck. Neuroanatomical localisation was cerebellum and/or brainstem. Haematology, biochemistry and blood pressure were within normal limits. Serology for common infectious diseases was negative. MRI demonstrated non-enhancing mild T2W and FLAIR hyperintensity and swelling of the whole cerebellum with more marked hyperintensity on the ventrolateral left hemisphere/flocculus (Fig. 1A,B,C). Increased intracranial pressure was suspected based on rostral transtentorial and foramen magnum herniation, cervical syringomyelia and lateral ventricular dilation, and therefore cerebrospinal fluid was not collected. Thoracic and abdominal CT was unremarkable. Differential diagnoses included inflammation (meningoencephalitis of unknown origin [MUO]), protozoal cerebellitis) or neoplasia (glioma/gliomatosis cerebri, lymphoma). MUO was considered likely; immunosuppressive prednisolone and mycophenolate and prophylactic clindamycin were started. After mild improvement, signs were static for 5 months. Mycophenolate was discontinued at 3 months due to gastrointestinal signs; owner declined another chemotherapeutic and prednisolone was continued. Two months later, the dog deteriorated (intention tremors, ataxia, intermittent collapses), with cerebellar changes being static on repeat MRI (Fig. 1D,E,F). Intravenous cytarabine was tried without response. Owners elected euthanasia. Histopathology revealed a disseminated proliferation of presumed glial origin infiltrating the subpial region, molecular layer, nuclei and white matter of the cerebellum bilaterally, the cerebrum, medulla, midbrain, hippocampus and medial geniculate bodies, consistent with gliomatosis cerebri (type 1). This case demonstrates a rare pattern of gliomatosis cerebri predominantly affecting the cerebellum. There was little progression in the imaging changes over a 5-month period, with clinical stability upon treatment.

Targeted Blood Brain Barrier Opening With Focused Ultrasound Induces Focal Macrophage/Microglial Activation in Experimental Autoimmune Encephalomyelitis

Experimental autoimmune encephalomyelitis (EAE) is a model of multiple sclerosis (MS). EAE reflects important histopathological hallmarks, dissemination, and diversity of the disease, but has only moderate reproducibility of clinical and histopathological features. Focal lesions are less frequently observed in EAE than in MS, and can neither be constrained to specific locations nor timed to occur at a pre-specified moment. This renders difficult any experimental assessment of the pathogenesis of lesion evolution, including its inflammatory, degenerative (demyelination and axonal degeneration), and reparatory (remyelination, axonal sprouting, gliosis) component processes. We sought to develop a controlled model of inflammatory, focal brain lesions in EAE using focused ultrasound (FUS). We hypothesized that FUS induced focal blood brain barrier disruption (BBBD) will increase the likelihood of transmigration of effector cells and subsequent lesion occurrence at the sonicated location. Lesion development was monitored with conventional magnetic resonance imaging (MRI) as well as with magnetic resonance elastography (MRE) and further analyzed by histopathological means. EAE was induced in 12 6–8 weeks old female C57BL/6 mice using myelin oligodendrocyte glycoprotein (MOG) peptide. FUS-induced BBBD was performed 6, 7, and 9 days after immunization in subgroups of four animals and in an additional control group. MRI and MRE were performed on a 7T horizontal bore small animal MRI scanner. Imaging was conducted longitudinally 2 and 3 weeks after disease induction and 1 week after sonication in control animals, respectively. The scan protocol comprised contrast-enhanced T1-weighted and T2-weighted sequences as well as MRE with a vibration frequency of 1 kHz. Animals were sacrificed for histopathology after the last imaging time point. The overall clinical course of EAE was mild. A total of seven EAE animals presented with focal T2w hyperintense signal alterations in the sonicated hemisphere. These were most frequent in the group of animals sonicated 9 days after immunization. Histopathology revealed foci of activated microglia/macrophages in the sonicated right hemisphere of seven EAE animals. Larger cellular infiltrates or apparent demyelination were not seen. Control animals showed no abnormalities on MRI and did not have clusters of activated microglia/macrophages at the sites targeted with FUS. None of the animals had hemorrhages or gross tissue damage as potential side effects of FUS. EAE-animals tended to have lower values of viscoelasticity and elasticity in the sonicated compared to the contralateral parenchyma. This trend was significant when comparing the right sonicated to the left normal hemisphere and specifically the right sonicated compared to the left normal cortex in animals that underwent FUS-BBBD 9 days after immunization (right vs. left hemisphere: mean viscoelasticity 6.1 vs. 7.2 kPa; p = 0.003 and mean elasticity 4.9 vs. 5.7 kPa, p = 0.024; right vs. left cortex: mean viscoelasticity 5.8 vs. 7.5 kPa; p = 0.004 and mean elasticity 5 vs. 6.5 kPa; p = 0.008). A direct comparison of the biomechanical properties of focal T2w hyperintensities with normal appearing brain tissue did not yield significant results. Control animals showed no differences in viscoelasticity between sonicated and contralateral brain parenchyma. We here provide first evidence for a controlled lesion induction model in EAE using FUS-induced BBBD. The observed lesions in EAE are consistent with foci of activated microglia that may be interpreted as targeted initial inflammatory activity and which have been described as pre-active lesions in MS. Such foci can be identified and monitored with MRI. Moreover, the increased inflammatory activity in the sonicated brain parenchyma seems to have an effect on overall tissue matrix structure as reflected by changes of biomechanical parameters.