Magnetic resonance metrics for identification of cuprizone-induced demyelination in the mouse model of neurodegeneration: a review.

Neurodegenerative disorders, including Multiple Sclerosis (MS), are heterogenous disorders which affect the myelin sheath of the central nervous system (CNS). Magnetic Resonance Imaging (MRI) provides a non-invasive method for studying, diagnosing, and monitoring disease progression. As an emerging research area, many studies have attempted to connect MR metrics to underlying pathophysiological presentations of heterogenous neurodegeneration. Most commonly, small animal models are used, including Experimental Autoimmune Encephalomyelitis (EAE), Theiler's Murine Encephalomyelitis (TMEV), and toxin models including cuprizone (CPZ), lysolecithin, and ethidium bromide (EtBr). A contrast and comparison of these models is presented, with focus on the cuprizone model, followed by a review of literature studying neurodegeneration using MRI and the cuprizone model. Conventional MRI methods including T1 Weighted (T1W) and T2 Weighted (T2W) Imaging are mentioned. Quantitative MRI methods which are sensitive to diffusion, magnetization transfer, susceptibility, relaxation, and chemical composition are discussed in relation to studying the CPZ model. Overall, additional studies are needed to improve both the sensitivity and specificity of MRI metrics for underlying pathophysiology of neurodegeneration and the relationships in attempts to clear the clinico-radiological paradox. We therefore propose a multiparametric approach for the investigation of MR metrics for underlying pathophysiology.

Distinguishing Tumor Cell Infiltration and Vasogenic Edema in the Peritumoral Region of Glioblastoma at the Voxel Level via Conventional MRI Sequences.

RATIONALE AND OBJECTIVES: The peritumoral region of glioblastoma (GBM) is composed of infiltrating tumor cells and vasogenic edema, which are difficult to distinguish manually on MRI. To distinguish tumor cell infiltration and vasogenic edema in GBM peritumoral regions, it is crucial to develop a method that is precise, effective, and widely applicable. MATERIALS AND METHODS: We retrieved the image characteristics of 379,730 voxels (marker of tumor infiltration) from 28 non-enhanced gliomas and 365,262 voxels (marker of edema) from the peritumoral edema region of 14 meningiomas on conventional MRI sequences (T1-weighted image, the contrast-enhancing T1-weighted image, the T2-weighted image, the T2-fluid attenuated inversion recovery image, and the apparent diffusion coefficient map). Using the SVM classifier, a model for predicting tumor cell infiltration and vasogenic edema at the voxel level was developed. The accuracy of the model's predictions was then evaluated using 15 GBM patients who underwent stereotactic biopsies. RESULTS: The area under the curve (AUC), accuracy, sensitivity, and specificity of the prediction model were 0.93, 0.84, 0.83, and 0.85 in the training set, and 0.90, 0.82, 0.83, and 0.83 in the test set (704,992 voxels), respectively. The pathology verification of 28 biopsy points with an accuracy of 0.79. CONCLUSION: At the voxel level, it seems possible to forecast tumor cell infiltration and vasogenic edema in the peritumoral region of GBM based on conventional MRI sequences.

A Review of Brain and Pituitary Gland MRI Findings in Patients with Ataxia and Hypogonadism.

The association of cerebellar ataxia and hypogonadism occurs in a heterogeneous group of disorders, caused by different genetic mutations often associated with a recessive inheritance. In these patients, magnetic resonance imaging (MRI) plays a pivotal role in the diagnostic workflow, with a variable involvement of the cerebellar cortex, alone or in combination with other brain structures. Neuroimaging involvement of the pituitary gland is also variable. Here, we provide an overview of the main clinical and conventional brain and pituitary gland MRI imaging findings of the most common genetic mutations associated with the clinical phenotype of ataxia and hypogonadism, with the aim of helping neuroradiologists in the identification of these disorders.

Added Value of Viscoelasticity for MRI-Based Prediction of Ki-67 Expression of Hepatocellular Carcinoma Using a Deep Learning Combined Radiomics (DLCR) Model.

This study aimed to explore the added value of viscoelasticity measured by magnetic resonance elastography (MRE) in the prediction of Ki-67 expression in hepatocellular carcinoma (HCC) using a deep learning combined radiomics (DLCR) model. This retrospective study included 108 histopathology-proven HCC patients (93 males; age, 59.6 ± 11.0 years) who underwent preoperative MRI and MR elastography. They were divided into training (n = 87; 61.0 ± 9.8 years) and testing (n = 21; 60.6 ± 10.1 years) cohorts. An independent validation cohort including 43 patients (60.1 ± 11.3 years) was included for testing. A DLCR model was proposed to predict the expression of Ki-67 with cMRI, including T2W, DW, and dynamic contrast enhancement (DCE) images as inputs. The images of the shear wave speed (c-map) and phase angle (φ-map) derived from MRE were also fed into the DLCR model. The Ki-67 expression was classified into low and high groups with a threshold of 20%. Both c and φ values were ranked within the top six features for Ki-67 prediction with random forest selection, which revealed the value of MRE-based viscosity for the assessment of tumor proliferation status in HCC. When comparing the six CNN models, Xception showed the best performance for classifying the Ki-67 expression, with an AUC of 0.80 ± 0.03 (CI: 0.79-0.81) and accuracy of 0.77 ± 0.04 (CI: 0.76-0.78) when cMRI were fed into the model. The model with all modalities (MRE, AFP, and cMRI) as inputs achieved the highest AUC of 0.90 ± 0.03 (CI: 0.89-0.91) in the validation cohort. The same finding was observed in the independent testing cohort, with an AUC of 0.83 ± 0.03 (CI: 0.82-0.84). The shear wave speed and phase angle improved the performance of the DLCR model significantly for Ki-67 prediction, suggesting that MRE-based c and φ-maps can serve as important parameters to assess the tumor proliferation status in HCC.

Treatment Response and Prognosis Evaluation in High-Grade Glioma: An Imaging Review Based on MRI.

In recent years, the development of advanced magnetic resonance imaging (MRI) technology and machine learning (ML) have created new tools for evaluating treatment response and prognosis of patients with high-grade gliomas (HGG); however, patient prognosis has not improved significantly. This is mainly due to the heterogeneity between and within HGG tumors, resulting in standard treatment methods not benefitting all patients. Moreover, the survival of patients with HGG is not only related to tumor cells, but also to noncancer cells in the tumor microenvironment (TME). Therefore, during preoperative diagnosis and follow-up treatment of patients with HGG, noninvasive imaging markers are needed to characterize intratumoral heterogeneity, and then to evaluate treatment response and predict prognosis, timeously adjust treatment strategies, and achieve individualized diagnosis and treatment. In this review, we summarize the research progress of conventional MRI, advanced MRI technology, and ML in evaluation of treatment response and prognosis of patients with HGG. We further discuss the significance of the TME in the prognosis of HGG patients, associate imaging features with the TME, indirectly reflecting the heterogeneity within the tumor, and shifting treatment strategies from tumor cells alone to systemic therapy of the TME, which may be a major development direction in the future. LEVEL OF EVIDENCE: 5 TECHNICAL EFFICACY STAGE: 4.

Contrasting the brain imaging features of MOG-antibody disease, with AQP4-antibody NMOSD and multiple sclerosis.

BACKGROUND: Identifying magnetic resonance imaging (MRI) markers in myelin-oligodendrocytes-glycoprotein antibody-associated disease (MOGAD), neuromyelitis optica spectrum disorder-aquaporin-4 positive (NMOSD-AQP4) and multiple sclerosis (MS) is essential for establishing objective outcome measures. OBJECTIVES: To quantify imaging patterns of central nervous system (CNS) damage in MOGAD during the remission stage, and to compare it with NMOSD-AQP4 and MS. METHODS: 20 MOGAD, 19 NMOSD-AQP4, 18 MS in remission with brain or spinal cord involvement and 18 healthy controls (HC) were recruited. Volumetrics, lesions and cortical lesions, diffusion-imaging measures, were analysed. RESULTS: Deep grey matter volumes were lower in MOGAD (p = 0.02) and MS (p = 0.0001), compared to HC and were strongly correlated with current lesion volume (MOGAD R = -0.93, p < 0.001, MS R = -0.65, p = 0.0034). Cortical/juxtacortical lesions were seen in a minority of MOGAD, in a majority of MS and in none of NMOSD-AQP4. Non-lesional tissue fractional anisotropy (FA) was only reduced in MS (p = 0.01), although focal reductions were noted in NMOSD-AQP4, reflecting mainly optic nerve and corticospinal tract pathways. CONCLUSION: MOGAD patients are left with grey matter damage, and this may be related to persistent white matter lesions. NMOSD-AQP4 patients showed a relative sparing of deep grey matter volumes, but reduced non-lesional tissue FA. Observations from our study can be used to identify new markers of damage for future multicentre studies.

Advanced Magnetic Resonance Imaging in Pediatric Glioblastomas.

The shortly upcoming 5th edition of the World Health Organization Classification of Tumors of the Central Nervous System is bringing extensive changes in the terminology of diffuse high-grade gliomas (DHGGs). Previously "glioblastoma," as a descriptive entity, could have been applied to classify some tumors from the family of pediatric or adult DHGGs. However, now the term "glioblastoma" has been divested and is no longer applied to tumors in the family of pediatric types of DHGGs. As an entity, glioblastoma remains, however, in the family of adult types of diffuse gliomas under the insignia of "glioblastoma, IDH-wildtype." Of note, glioblastomas still can be detected in children when glioblastoma, IDH-wildtype is found in this population, despite being much more common in adults. Despite the separation from the family of pediatric types of DHGGs, what was previously labeled as "pediatric glioblastomas" still remains with novel labels and as new entities. As a result of advances in molecular biology, most of the previously called "pediatric glioblastomas" are now classified in one of the four family members of pediatric types of DHGGs. In this review, the term glioblastoma is still apocryphally employed mainly due to its historical relevance and the paucity of recent literature dealing with the recently described new entities. Therefore, "glioblastoma" is used here as an umbrella term in the attempt to encompass multiple entities such as astrocytoma, IDH-mutant (grade 4); glioblastoma, IDH-wildtype; diffuse hemispheric glioma, H3 G34-mutant; diffuse pediatric-type high-grade glioma, H3-wildtype and IDH-wildtype; and high grade infant-type hemispheric glioma. Glioblastomas are highly aggressive neoplasms. They may arise anywhere in the developing central nervous system, including the spinal cord. Signs and symptoms are non-specific, typically of short duration, and usually derived from increased intracranial pressure or seizure. Localized symptoms may also occur. The standard of care of "pediatric glioblastomas" is not well-established, typically composed of surgery with maximal safe tumor resection. Subsequent chemoradiation is recommended if the patient is older than 3 years. If younger than 3 years, surgery is followed by chemotherapy. In general, "pediatric glioblastomas" also have a poor prognosis despite surgery and adjuvant therapy. Magnetic resonance imaging (MRI) is the imaging modality of choice for the evaluation of glioblastomas. In addition to the typical conventional MRI features, i.e., highly heterogeneous invasive masses with indistinct borders, mass effect on surrounding structures, and a variable degree of enhancement, the lesions may show restricted diffusion in the solid components, hemorrhage, and increased perfusion, reflecting increased vascularity and angiogenesis. In addition, magnetic resonance spectroscopy has proven helpful in pre- and postsurgical evaluation. Lastly, we will refer to new MRI techniques, which have already been applied in evaluating adult glioblastomas, with promising results, yet not widely utilized in children.

Conventional MRI findings in hereditary degenerative ataxias: a pictorial review.

PURPOSE: Cerebellar ataxias are a large and heterogeneous group of disorders. The evaluation of brain parenchyma via MRI plays a central role in the diagnostic assessment of these conditions, being mandatory to exclude the presence of other underlying causes in determining the clinical phenotype. Once these possible causes are ruled out, the diagnosis is usually researched in the wide range of hereditary or sporadic ataxias. METHODS: We here propose a review of the main clinical and conventional imaging findings of the most common hereditary degenerative ataxias, to help neuroradiologists in the evaluation of these patients. RESULTS: Hereditary degenerative ataxias are all usually characterized from a neuroimaging standpoint by the presence, in almost all cases, of cerebellar atrophy. Nevertheless, a proper assessment of imaging data, extending beyond the mere evaluation of cerebellar atrophy, evaluating also the pattern of volume loss as well as concomitant MRI signs, is crucial to achieve a proper diagnosis. CONCLUSION: The integration of typical neuroradiological characteristics, along with patient's clinical history and laboratory data, could allow the neuroradiologist to identify some conditions and exclude others, addressing the neurologist to the more appropriate genetic testing.

The role of "penumbra sign" and diffusion-weighted imaging in adnexal masses: do they provide a clue in differentiating tubo-ovarian abscess from ovarian malignancy?

PURPOSE: To evaluate the role of "penumbra sign", diffusion-weighted imaging (DWI), and the apparent diffusion coefficient (ADC) value in differentiating tubo-ovarian abscess (TOA) from ovarian malignancy. MATERIAL AND METHODS: Thirty-six patients with 50 adnexal masses (tubo-ovarian abscess, n = 24; ovarian malignancy, n = 26), who underwent magnetic resonance imaging (MRI) with DWI, were retrospectively evaluated. "Penumbra sign" (hyperintense rim on T1W images), diffusion restriction, and mean apparent diffusion coefficient (ADC) values from cystic (c-ADC) and solid (s-ADC) components were evaluated for all the masses. RESULTS: "Penumbra sign" on T1W images was significantly more common in the TOA group (n = 21, 87.5%) than in the ovarian malignancy group (n = 2, 7.7%) (p < 0.001). Similarly, diffusion restriction in the cystic component was more frequent in the TOA group (n = 24, 100% vs. n = 2, 10.5%; p < 0.001). In contrast, diffusion restriction in the solid component was more common in the ovarian malignancy group (n = 5, 20.8% vs. n = 26, 100%; p < 0.001). The mean c-ADC value was significantly lower in TOAs (p < 0.001). A c-ADC value of 1.31 × 10-3 mm2/s may be an optimal cut-off in distinguishing TOAs from ovarian malignancies. Conversely, the mean s-ADC value was significantly lower in the ovarian malignancy group (p < 0.001). An s-ADC value of 0.869 × 10-3 mm2/s may be an optimal cut-off in differentiating ovarian malignancies from TOAs (p < 0.001). ROC curve analysis showed that c-ADC values had a higher diagnostic accuracy than s-ADC values. CONCLUSIONS: "Penumbra sign" on T1W images, diffusion characteristics, and ADC values provide important clues in addition to conventional MR imaging features in differentiating TOA from ovarian malignancy.

The Diagnostic Value of Conventional MRI and CT Features in the Identification of the IDH1-Mutant and 1p/19q Co-Deletion in WHO Grade II Gliomas.

RATIONALE AND OBJECTIVES: The classification of patients based on pathology and molecular features is important for improving WHO grade II glioma patient prognosis, especially for the initially diagnosed patients. Less invasive and more convenient methods for the prediction of the pathological type and gene status are desired. MATERIALS AND METHODS: This study investigates the ability to use conventional magnetic resonance imaging (MRI) and computed tomography (CT) features for determining the Isocitrate Dehydrogenase (IDH)-mutant and 1p/19q-codeletion status, through a retrospective review of information obtained from 189 WHO grade II glioma patients. Diffuse astrocytoma (IDH-mutant), Diffuse astrocytoma (IDH- wildtype) and Oligodendroglioma (IDH-mutant and 1p/19q co-deletion) were included in this cohort. All patients were divided into IDH-mutant group and IDH-wildtype group according to the IDH R132H mutation status. Moreover, all patients were divided into 1p/19q co-deletion group and 1p/19q non-codeletion group according to the 1p and 19q chromosome status. Patients underwent pre-operative CT and MRI scans, followed by operation and histopathological analyses, including immunohistochemistry and polymerase chain reaction analysis for IDH mutants, and fluorescence capillary electrophoresis analysis for the 1p/19q co-deletion. The χ2 test, logistical regression and receiver operating characteristic curve analysis were conducted for statistical analysis. RESULTS: IDH-mutant group patients exhibited a higher calcification frequency (25.2% vs 2.4%, p = 0.006) and lower frequency of T1 enhancement (20.4% vs 38.1%, p = 0.028) comparing patients in IDH-wildtype group, while 1p/19q co-deletion group patients exhibited a higher calcification frequency (46.67% vs 2.6%, p < 0.001) and lower homogenous signal frequency in T2WI (12.0% vs 31.6%, p = 0.014), sharp lesion margins (14.7% vs 43.0%, p = 0.010), T2/fluid attenuated inversion recovery mismatch signs (22.7% vs 50.9%, p = 0.001), and subventricular zone involvement (64.0% vs 15.8%, p = 0.021) comparing patients in 1p/19q non-codeletion group. According to the results of receiver operating characteristic analysis, these features were observed to have certain diagnostic abilities, especially with regard to combination parameters, which had a high diagnostic capability, with an area under the curve of 0.848. CONCLUSION: Conventional MRI and CT features, which still represent the most convenient and widely used predictive method, might be a promising noninvasive predictor for differentiating between varied WHO grade II gliomas. Patients with calcification and T1 nonenhancement are more likely to be IDH-mutant. Moreover, patients with noncalcification, homogenous signal, sharp lesion margins, subventricular zone involvement on T2 and T2/fluid attenuated inversion recovery mismatch signs are more likely to be 1p/19q non-codeletion.

Acute optic nerve lesions in first-ever NMOSD-related optic neuritis using conventional brain MRI: A Latin American multicenter study.

BACKGROUND: Few studies regarding MRI-defined acute optic nerve lesions (aONL) in patients with first-ever neuromyelitis optica spectrum disorder (NMOSD)-related optic neuritis (ON) have been reported worldwide and none of them was conducted in Latin America (LATAM). Therefore, we aimed to assess the frequency of aONL at disease onset using conventional brain MRI in LATAM. METHODS: We reviewed the medical records and brain MRIs (≤30 days from ON onset) of patients with ON as first lifetime NMOSD attack. Patients from Argentina (n=48), Ecuador (n=24), Brazil (n=22), Venezuela (n=10) and Mexico (n=8) were included, and further divided into two subgroups according to either presence (P-MRI) or absence (A-MRI) of aONL (T2 hyperintensity and/or contrast enhancement). Clinical, paraclinical, imaging and prognostic data were compared. RESULTS: A total of 112 patients were included and aONL were found in 86 (76.7%) at disease onset. Aquaporin-4 antibodies were detected in 69.6%. Non-Caucasian patients comprised 59.8% of the total cohort. In P-MRI, conventional brain MRI showed isolated or combined unilateral (54.4%, [8.5% of these aONL were associated with chiasmatic lesions]) and bilateral (46.6%, [35.9% of these aONL were associated with chiasmatic lesions]) lesions. Thus, 100% of chiasmatic lesions were associated with unilateral or bilateral lesions. No statistically significant differences were found in age, gender, ethnicity, clinical course, mean follow-up time, disability, and spinal cord MRI findings. However, rituximab use was higher in P-MRI than in A-MRI (p=0.006). CONCLUSIONS: More than three quarters of LATAM patients with first-ever NMOSD-related ON have aONL detected by brain MRI. Unilateral lesions were the most common finding. Further studies including different ethnicities are needed to assess the generalizability of our results.

Newer magnetic resonance imaging techniques in neurocysticercosis.

INTRODUCTION: The definitive diagnosis of neurocysticercosis continues to be challenging. We evaluate the role of newer magnetic resonance imaging techniques including constructive interference in steady state, susceptibility-weighted imaging, arterial spin labelling and magnetic resonance spectroscopy in the diagnosis of neurocysticercosis. AIMS AND OBJECTIVES: To study the utility of newer magnetic resonance imaging sequences in the diagnosis of neurocysticercosis. PATIENTS AND METHODS: Eighty-five consecutive patients with neurocysticercosis attending a tertiary care hospital and teaching centre in northern India were included in the study. The diagnosis of neurocysticercosis was made by the Del Brutto criteria. All patients received treatment according to standard guidelines and were followed at 3-month intervals. The following magnetic resonance sequences were performed at baseline: T1 and T2-weighted axial sequences; T2 fluid-attenuated inversion recovery axial sequences; diffusion-weighted imaging; susceptibility-weighted imaging; pre and post-contrast T1-weighted imaging; heavily T2-weighted thin sections (constructive interference in steady state); arterial spin labelling (n = 19); and magnetic resonance spectroscopy (n = 24). RESULTS: The mean (±SD) age was 29.4 ± 12.9 years and 76.5% were men. Seizures were the commonest symptom (89.4%) followed by headache (24.3%), encephalitis (9.4%) and raised intracranial pressure (9.4%). Scolex could be visualised in 43.7%, 55.5% and 61.2% of neurocysticercosis patients using conventional, susceptibility-weighted angiography and constructive interference in steady state imaging sequences, respectively. Susceptibility-weighted angiography and constructive interference in steady state images resulted in significantly higher (P < 0.01) visualisation of scolex compared to conventional sequences. CONCLUSION: Newer magnetic resonance imaging modalities have a lot of promise for improving the radiological diagnosis of neurocysticercosis.

Comparison of Conventional, Diffusion, and Perfusion MRI Between Low-Grade and Anaplastic Extraventricular Ependymoma.

OBJECTIVE. The purpose of this study was to investigate and compare conventional MRI, DWI, and dynamic susceptibility contrast-enhanced perfusion-weighted imaging (DSC-PWI) characteristics between low-grade and anaplastic extraventricular ependymomas. MATERIALS AND METHODS. Twenty-six patients with extraventricular ependymomas (19 anaplastic and seven low-grade) who underwent preoperative MRI were enrolled in this retrospective study. Conventional MRI and DWI were performed in all patients; DSCPWI was performed in 15 patients (11 with anaplastic ependymoma and four with low-grade ependymoma). Demographics, conventional MRI features, minimum relative apparent diffusion coefficient (rADCmin), and maximum relative cerebral blood volume (rCBVmax) of the low-grade and anaplastic ependymomas were compared. Diagnostic performance with optimal cutoff values was determined. RESULTS. Anaplastic extraventricular ependymomas were more likely to be located in the superficial supratentorial cerebral hemisphere (p = 0.026) and to present with pial and cortical involvement (p = 0.028 and 0.013, respectively) and necrotic degeneration (p = 0.014). The mean rADCmin ± SD of anaplastic ependymoma was significantly lower than that of low-grade ependymoma (0.8 ± 0.2 vs 1.2 ± 0.3, p = 0.002). The mean rCBVmax of anaplastic ependymoma was significantly higher than that of low-grade ependymoma (15.7 ± 5.3 vs 9.0 ± 4.4, p = 0.042). The cutoff values in grading extraventricular ependymoma were 1.02 for rADCmin and 10.43 for rCBVmax. Combining conventional MRI, DWI, and DSC-PWI allowed the best differentiation of low-grade and anaplastic ependymoma (AUC = 1.00). CONCLUSION. Conventional MRI, DWI, and DSC-PWI techniques may aid in assessing and grading extraventricular ependymomas.

Longitudinal analysis of white matter and cortical lesions in multiple sclerosis.

PURPOSE: The goals of this study were to assess the performance of a novel lesion segmentation tool for longitudinal analyses, as well as to validate the generated lesion progression map between two time points using conventional and non-conventional MR sequences. MATERIAL AND METHODS: The lesion segmentation approach was evaluated with (LeMan-PV) and without (LeMan) the partial volume framework using "conventional" and "non-conventional" MR imaging in a two-year follow-up prospective study of 32 early RRMS patients. Manual segmentations of new, enlarged, shrunken, and stable lesions were used to evaluate the performance of the method variants. The true positive rate was estimated for those lesion evolutions in both white matter and cortex. The number of false positives was compared with two strategies for longitudinal analyses. New lesion tissue volume estimation was evaluated using Bland-Altman plots. Wilcoxon signed-rank test was used to evaluate the different setups. RESULTS: The best median of the true positive rate was obtained using LeMan-PV with non-conventional sequences (P < .05): 87%, 87%, 100%, 83%, for new, enlarged, shrunken, and stable WM lesions, and 50%, 60%, 50%, 80%, for new, enlarged, shrunken, and stable cortical lesions, respectively. Most of the missed lesions were below the mean lesion size in each category. Lesion progression maps presented a median of 0 false positives (range:0-9) and the partial volume framework improved the volume estimation of new lesion tissue. CONCLUSION: LeMan-PV exhibited the best performance in the detection of new, enlarged, shrunken and stable WM lesions. The method showed lower performance in the detection of cortical lesions, likely due to their low occurrence, small size and low contrast with respect to surrounding tissues. The proposed lesion progression map might be useful in clinical trials or clinical routine.

Magnetic resonance-guided direct shoulder arthrography for the detection of superior labrum anterior-posterior lesions using an open 1.0-T MRI scanner.

PURPOSE: Direct magnetic resonance arthrography (MRA) offers increased diagnostic accuracy compared to conventional magnetic resonance imaging (MRI) in the detection of superior labrum anterior-posterior (SLAP) lesions. The aim of the present study was to present the technique of magnetic resonance-guided direct shoulder arthrography (MDSA), to evaluate the diagnostic value of this novel MRA procedure to detect SLAP lesions in comparison to the currently practiced MRI, and to correlate the radiological findings to the respective arthroscopic findings. MATERIAL AND METHODS: Fifty-six patients with clinical signs of a SLAP lesion underwent both MRI examination and MDSA prior to arthroscopic surgery. The MRI of both interventions were compared with the arthroscopic findings. Statistical analysis was performed using the McNemar test. RESULTS: Sensitivity, specificity, and accuracy for detecting SLAP lesions were 23%, 88%, and 54% on MRI and 80%, 81%, and 80% on MDSA, respectively. Sensitivity (p < 0.001) and accuracy (p = 0.001) in detection of SLAP lesions were significantly higher by MDSA whereas accuracy showed no significant differences (p = 0.625). CONCLUSIONS: The MDSA can be performed in an open 1.0-T MRI scanner with a high level of technical success and a reasonable methodical effort. The modification of MRA provides the requirements as a practicable routine shoulder magnetic resonance examination including arthrography to detect SLAP lesions. The diagnostic value is significantly better than MRI examinations without included arthrography, which currently predominates the clinical practice to investigate shoulder pathology.

Noninvasive assessment of H3 K27M mutational status in diffuse midline gliomas by using apparent diffusion coefficient measurements.

PURPOSE: H3 K27M-mutant diffuse midline gliomas are associated with worse prognosis than H3 K27M wild-type gliomas. In the present study, we sought to evaluate the conventional magnetic resonance imaging (cMRI) of H3 K27M-mutant glioma and examine whether diffusion-weighted imaging (DWI) derived apparent diffusion coefficient (ADC) could noninvasively predict H3 K27M mutational status in brain diffuse midline gliomas. MATERIALS AND METHODS: The institutional review board approved this study and waived the requirement for informed consent. Thirty-eight patients with brain diffuse midline gliomas were retrospectively reviewed. The parameters of preoperative cMRI were evaluated. The minimal ADC, peritumoral ADC, ratio of minimal ADC, and ratio of peritumoral ADC were measured, and significant differences between the two groups were identified by logistic regression analysis adjusted for age and tumor location. Receiver operating characteristic curves and logistic regression analysis adjusted for age and tumor location were used to assess the diagnostic performances of the minimal ADC, peritumoral ADC, ratio of minimal ADC, and ratio of peritumoral ADC. RESULTS: H3 K27M-mutant gliomas in different locations have diverse imaging characteristics. Minimal ADC, peritumoral ADC, ratio of minimal ADC, and ratio of peritumoral ADC values were significantly lower in the H3 K27M-mutant gliomas than in the wild-type gliomas (P < 0.05). The combination of ratio of minimal ADC and ratio of peritumoral ADC provided the largest area under the curve (AUC) of 0.872 in defining H3 K27M-mutational status. CONCLUSIONS: The combination of ratio of minimal ADC and ratio of peritumoral ADC can noninvasively detect the H3 K27M mutational status in brain diffuse midline gliomas.

Conventional Structural Magnetic Resonance Imaging in Differentiating Chronic Disorders of Consciousness.

Differential diagnosis of unresponsive wakefulness syndrome (UWS) and minimally conscious state (MCS) is one of the most challenging problems for specialists who deal with chronic disorders of consciousness (DOC). The aim of the current study was to develop a conventional MRI-based scale and to evaluate its role in distinguishing chronic disorders of consciousness (Disorders of Consciousness MRI-based Distinguishing Scale, DOC-MRIDS). Data were acquired from 30 patients with clinically diagnosed chronic disorders of consciousness. All patients underwent conventional MRI using a Siemens Verio 3.0 T scanner, which included T2 and T1 sequences for patient assessment. Diffuse cortical atrophy, ventricular enlargement, sulcal widening, leukoaraiosis, brainstem and/or thalamus degeneration, corpus callosum degeneration, and corpus callosum lesions were assessed according to DOC-MRIDS criteria, with a total score calculation. The ROC-analysis showed that a reasonable threshold DOC-MRIDS total score was 5.5, that is, patients with DOC-MRIDS total score of 6 and above were classified as UWS and 5 and below as MCS, with sensitivity of 82.4% and specificity of 92.3%. The novel structural MRI-based scale for the assessment of typical brain lesions in patients with chronic DOC is relatively easy to apply, and provides good specificity and sensitivity values for discrimination between UWS and MCS.

Value of conventional MRI and diffusion tensor imaging parameters in predicting surgical outcome in patients with degenerative cervical myelopathy.

BACKGROUND: In addition to conventional magnetic resonance imaging (cMRI), diffusion tensor imaging (DTI) has been investigated as a potential diagnostic and prognostic tool for patients with degenerative cervical myelopathy (DCM). OBJECTIVE: To assess the efficacy of cMRI and DTI parameters in prediction of surgical outcome in DCM patients. METHODS: One hundred and forty-two patients with DCM who underwent presurgical cMRI and DTI of the cervical spine were included. Quantitative parameters obtained by cMRI included compression ratio (CR), transverse area (TA), and signal intensity ratio (SIR). DTI was evaluated for apparent diffusion coefficient (ADC) and fractional anisotropy (FA). The Japanese Orthopaedic Association (JOA) score and recovery rate were used to evaluate clinical outcomes. A JOA recovery rate < 50% was defined as a poor surgical outcome. The relationship of surgical outcome with various imaging parameters was examined. Receiver operating characteristic (ROC) curves were used to measure the predictive ability and determine the best cut-off values of the quantitative parameters. RESULTS: By ROC curve analyses of imaging parameters, the largest area under the ROC curve (AUC) was for FA (0.750), followed by ADC (0.719), TA (0.716), SIR (0.673), and CR (0.591). The cut-off values with the best compromise between sensitivity and specificity were set at 0.390 for FA, 1.344 × 10-3 mm2/s for ADC, 46.02 mm2 for TA, 1.556 for SIR, and 26.56% for CR. Multivariate logistic regression model revealed that JOA score ⩽ 8 points, TA ⩽ 46.02 mm2, and FA ⩽ 0.390 were independently associated with poor surgical outcome. The AUC value for the three-predictor model was 0.871, indicating strong predictive discrimination, and was significantly higher than the AUC value for the model containing only the JOA score (0.763; P= 0.003). CONCLUSIONS: JOA score is a reasonable predictor of surgical outcome in DCM. However, a model inclusive of TA and FA provides superior predictive ability. Thus, quantitative analysis of cMRI and DTI is useful for predicting surgical outcome in DCM.

Comparison of MRI techniques for detecting microadenomas in Cushing's disease.

OBJECTIVE Many centers use conventional and dynamic contrast-enhanced MRI (DMRI) sequences in patients with Cushing's disease. The authors assessed the utility of the 3D volumetric interpolated breath-hold examination, a spoiled-gradient echo 3D T1 sequence (SGE) characterized by superior soft tissue contrast and improved resolution, compared with DMRI and conventional MRI (CMRI) for detecting microadenomas in patients with Cushing's disease. METHODS This study was a blinded assessment of pituitary MRI in patients with proven Cushing's disease. Fifty-seven patients who had undergone surgery for Cushing's disease (10 male, 47 female; age range 13-69 years), whose surgical findings were considered to represent a microadenoma, and who had been examined with all 3 imaging techniques were included. Thus, selection emphasized patients with prior negative or equivocal MRI on referral. The MRI annotations were anonymized and 4 separate imaging sets were independently read by 3 blinded, experienced clinicians: a neuroradiologist and 2 pituitary surgeons. RESULTS Forty-eight surgical specimens contained an adenoma (46 ACTH-staining adenomas, 1 prolactinoma, and 1 nonfunctioning microadenoma). DMRI detected 5 adenomas that were not evident on CMRI, SGE detected 8 adenomas not evident on CMRI, including 3 that were not evident on DMRI. One adenoma was detected on DMRI that was not detected on SGE. McNemar's test for efficacy between the different MRI sets for tumor detection showed that the addition of SGE to CMRI increased the number of tumors detected from 18 to 26 (p = 0.02) based on agreement of at least 2 of 3 readers. CONCLUSIONS SGE shows higher sensitivity than DMRI for detecting and localizing pituitary microadenomas, although rarely an adenoma is detected exclusively by DMRI. SGE should be part of the standard MRI protocol for patients with Cushing's disease.

What are the differentiating clinical and MRI-features of enchondromas from low-grade chondrosarcomas?

OBJECTIVES: To evaluate the role of clinical assessment, conventional and dynamic contrast-enhanced MRI in differentiating enchondromas from chondrosarcomas of long bone. METHODS: The following clinical and MRI findings were assessed: age, gender, pain, pain attributable to lesion, tumour location, tumour length, presence, depth of endosteal scalloping, bone marrow oedema, soft tissue oedema, cortical destruction, periosteal reaction, bone expansion, macroscopic fat, calcification, soft tissue mass, haemorrhage, dynamic contrast-enhanced MRI. Clinical and MRI findings were compared with histopathological grading. RESULTS: Sixty patients with central chondroid tumours were included (27 enchondromas, 10 cartilaginous lesions of unknown malignant potential, 15 grade 1 chondrosarcomas, 8 high-grade chondrosarcomas). Pain attributed to lesion, tumour length, endosteal scalloping > 2/3, cortical destruction, bone expansion and soft tissue mass were differentiating features between enchondromas and grade 1 chondrosarcomas. Dynamic contrast-enhanced MRI could not differentiate enchondromas from grade 1 chondrosarcomas. CONCLUSIONS: Previously reported imaging signs of chondrosarcomas are useful in the diagnosis of grade 1 lesions but have lower sensitivity than in higher grade lesions. Deep endosteal scalloping is the most sensitive imaging sign of grade 1 chondrosarcomas. Pain due to the lesion is an important clinical sign of grade 1 chondrosarcomas. Dynamic contrast-enhanced MRI is not useful in differentiating enchondromas from grade 1 chondrosarcomas. KEY POINTS: • Differentiation of enchondroma from low-grade chondrosarcoma is challenging for radiologists and pathologists. • The utility of clinical assessment, conventional and dynamic contrast-enhanced MRI was uncertain. • Clinical assessment and conventional MRI aid in differentiating enchondromas from low-grade chondrosarcoma. • Dynamic contrast-enhanced MRI cannot differentiate enchondromas from grade 1 chondrosarcoma.