Potential savings in the diagnosis of vestibular schwannoma.

INTRODUCTION: Magnetic resonance imaging (MRI) is used to screen patients at risk for vestibular schwannoma (VS). These MRIs are costly and have an extremely low yield; only 3% of patients in the screening population has an actual VS. It might be worthwhile to develop a test to predict VS and refer only a subset of all patients for MRI. OBJECTIVE: To examine the potential savings of such a hypothetical diagnostic test before MRI. DESIGN: We built a decision analytical model of the diagnostic strategy of VS. Input was derived from literature and key opinion leaders. The current strategy was compared to hypothetical new strategies, assigning MRI to the following: (i) all patients with pathology, (ii) all patients with important pathology and (iii) only patients with VS. This resulted in potential cost savings for each strategy. We conducted a budget impact analysis to predict nationwide savings for the Netherlands and the United Kingdom (UK), and a probabilistic sensitivity analysis to address uncertainty. RESULTS: Mean savings ranged from €256 (95%CI €250 - €262) or approximately US$284 (95%CI US$277 - US$291) per patient for strategy 1 to €293 (95%CI €290 - €296) or approximately US$325 (95%CI US$322 - US$328) per patient for strategy 3. Future diagnostic strategies can cost up to these amounts per patient and still be cost saving. Annually, for the Netherlands, €2.8 to €3.2 million could be saved and €10.8 to €12.3 million for the UK. CONCLUSIONS: The model shows that substantial savings could be generated if it is possible to further optimise the diagnosis of VS.

Diagnostic accuracy of high-resolution T2-weighted MRI vs contrast-enhanced T1-weighted MRI to screen for cerebellopontine angle lesions in symptomatic patients.

OBJECTIVE: To evaluate diagnostic accuracy of high-resolution T2-weighted MRI (T2w) for detecting cerebellopontine angle (CPA) lesions compared to a combined protocol including gadolinium enhanced T1-weighted MRI (GdT1w). SETTING: Department of Radiology & Nuclear Medicine, Radboud University Medical Centre, Nijmegen, The Netherlands. PARTICIPANTS: A random sample of MRIs from 350 patients (700 CPAs) with asymmetrical audiovestibular complaints was used, acquired between 2013 and 2016. MAIN OUTCOME MEASURES: Sensitivity, specificity, positive and negative predictive values of T2w results compared to GdT1w and, in patients with any suggestion of CPA pathology, to the complete examination (T1w, GdT1w and T2w). Inter-rater agreement between an experienced neuroradiologist and a less experienced observer was calculated. RESULTS: Results of 678 CPAs in 340 patients were analysed. On T2w, the neuroradiologist identified all 27 lesions >2 mm in size out of a total of 30 CPA lesions (sensitivity: 90% [95% CI: 73.5%-97.9%]). Negative predictive value reached 99.5% (95% CI: 98.7-99.9). One missed lesion of 2 mm would have been detected in clinical practice, as this was one of 14 patients for which additional GdT1w would have been ordered based on T2w alone, increasing sensitivity to 93% (95% CI: 77.9%-99.2%) and negative predictive value to 99.7% (95% CI: 98.9%-100%). Inter-rater agreement for T2w was 98% (95% CI: 96.4-98.8). CONCLUSION: T2w has a very high diagnostic accuracy for the presence of CPA lesions in patients with asymmetrical audiovestibular complaints. However, in a screening protocol with T2w only, smallest vestibular schwannomas as well as rare differential diagnoses that probably only would be detected on GdT1w may remain unnoticed.

Chronic temporomandibular joint pain: two cases of osteoid osteoma and a review of the literature.

Osteoid osteoma is a benign bone tumour with self-limiting growth potential occurring in any part of the body. Two rare cases of a pathologically proven osteoid osteoma invading the temporomandibular joint (TMJ) are reported herein. This article also reviews the cases of osteoid osteoma of the craniofacial complex reported in the English-language literature to date. Although the clinical presentation of osteoid osteoma in the jaw differs from that of osteoid osteoma in the more common locations, the radiographic features are similar. In both cases presented, computed tomography revealed a small round osseous lesion with sharp margins in the TMJ. Bone scintigraphy was performed in order to differentiate the lesions from other osseous lesions. Both patients underwent surgical excision of the lesion with immediate relief of the pain. The importance of early recognition of the clinical and imaging characteristics of an osteoid osteoma of the TMJ is emphasized, in order to prevent misdiagnosis and avoid discouraging therapies.

Visualization of human inner ear anatomy with high-resolution MR imaging at 7T: initial clinical assessment.

BACKGROUND AND PURPOSE: In many centers, MR imaging of the inner ear and auditory pathway performed on 1.5T or 3T systems is part of the preoperative work-up of cochlear implants. We investigated the applicability of clinical inner ear MR imaging at 7T and compared the visibility of inner ear structures and nerves within the internal auditory canal with images acquired at 3T. MATERIALS AND METHODS: Thirteen patients with sensorineural hearing loss eligible for cochlear implantation underwent examinations on 3T and 7T scanners. Two experienced head and neck radiologists evaluated the 52 inner ear datasets. Twenty-four anatomic structures of the inner ear and 1 overall score for image quality were assessed by using a 4-point grading scale for the degree of visibility. RESULTS: The visibility of 11 of the 24 anatomic structures was rated higher on the 7T images. There was no significant difference in the visibility of 13 anatomic structures and the overall quality rating. A higher incidence of artifacts was observed in the 7T images. CONCLUSIONS: The gain in SNR at 7T yielded a more detailed visualization of many anatomic structures, especially delicate ones, despite the challenges accompanying MR imaging at a high magnetic field.

Neuropsychiatric systemic lupus erythematosus: lessons learned from magnetic resonance imaging.

OBJECTIVE: The clinical manifestations of nervous system involvement in systemic lupus erythematosus (neuropsychiatric SLE [NPSLE]) are highly diverse, and their etiology is incompletely understood. The aim of this study was to provide an inventory of abnormalities on conventional brain magnetic resonance imaging (MRI) in NPSLE and to interpret the findings in relation to possible underlying pathogenetic mechanisms. METHODS: MR images of the first episode of active NPSLE in 74 patients were retrospectively reviewed. All patients fulfilled the American College of Rheumatology (ACR) 1982 revised criteria for the classification of SLE and were classified according to the 1999 ACR case definitions for NPSLE syndromes. We excluded patients with a history of brain disease and patients in whom other mechanisms unrelated to SLE caused the neuropsychiatric symptoms. RESULTS: The principal findings were: 1) focal hyperintensities in white matter (WM) (49% of all patients) or both WM and gray matter (GM) (5% of all patients), suggestive of vasculopathy or vasculitis; 2) more widespread, confluent hyperintensities in the WM, suggestive of chronic hypoperfusion due to the same mechanisms; 3) diffuse cortical GM lesions (12% of all patients), compatible with an immune response to neuronal components or postseizure changes; and 4) absence of MRI abnormalities, despite signs and symptoms of active disease (42% of all patients). CONCLUSION: Several distinct brain MRI patterns were observed in patients with active NPSLE, suggestive of different pathogenetic mechanisms. To advance our understanding of the various processes leading to NPSLE, the radiographic manifestations may be a good starting point and useful for categorization of patients in further research.

Correlation of magnetization transfer ratio histogram parameters with neuropsychiatric systemic lupus erythematosus criteria and proton magnetic resonance spectroscopy: association of magnetization transfer ratio peak height with neuronal and cognitive dysfunction.

OBJECTIVE: To investigate whether, in neuropsychiatric systemic lupus erythematosus (NPSLE) patients, magnetization transfer ratio (MTR) histogram parameters are related to neurochemical findings obtained using proton magnetic resonance spectroscopy (1H-MRS) and to determine whether MTR histogram changes are linked to specific SLE and NPSLE characteristics. METHODS: Eighteen SLE patients (15 female, 3 male; mean +/- SD age 42.8 +/- 12.8 years), 34 NPSLE patients (32 female, 2 male; mean +/- SD age 35.9 +/- 12.2 years), and 15 healthy controls (14 female, 1 male; mean +/- SD age 44.7 +/- 9.6 years) underwent magnetization transfer imaging and 1H-MRS. Whole-brain MTR histogram parameters were associated with 1H-MRS metabolite ratios, certain SLE criteria, and neuropsychiatric syndromes. RESULTS: No differences were found in the MTR histogram parameters between SLE patients and NPSLE patients. NPSLE patients had a lower MTR histogram peak height than did the healthy controls. The MTR histogram peak height and the mean height were significantly associated with the N-acetylaspartate to creatinine ratio, suggesting neuronal dysfunction. Of all SLE criteria, renal dysfunction and arthritis were associated with MTR histogram parameters. After corrections for age, sex, and these SLE criteria, of the various neuropsychiatric syndromes only cognitive dysfunction was associated with the MTR histogram peak height. CONCLUSION: The MTR peak height is lower in NPSLE patients than in healthy controls. MTR peak height reflects neuronal dysfunction, as detected by 1H-MRS. Furthermore, the MTR peak height is associated with cognitive dysfunction but not with the other neuropsychiatric syndromes evaluated in our study.

Sources of variation in multi-centre brain MTR histogram studies: body-coil transmission eliminates inter-centre differences.

OBJECT: 1. Identify sources of variation affecting Magnetisation Transfer Ratio (MTR) histogram reproducibility between-centres. 2. Demonstrate complete elimination of inter-centre difference. MATERIALS AND METHODS: Six principle sources of variation were summarised and analysed. These are: the imager coil used for radiofrequency (RF) transmission, imager stability, the shape and other parameters describing the Magnetisation Transfer (MT) pulse, the MT sequence used (including its parameters), the image segmentation methodology, and the histogram generation technique. Transmit field nonuniformity and B1 errors are often the largest factors. PLUMB (Peak Location Uniformity in MTR histograms of the Brain) plots are a convenient way of visualising differences. Five multi-centres studies were undertaken to investigate and minimise differences. RESULTS: Transmission using a body coil, with a close-fitting array of surface coils for reception, gave the best uniformity. Differences between two centres, having MR imagers from different manufacturers, were completely eliminated by using body coil excitation, making a small adjustment to the MT pulse flip angle, and carrying out segmentation at a single centre. Histograms and their peak location and height values were indistinguishable. CONCLUSIONS: Body coil excitation is preferred for multi-centre studies. Analysis (segmentation and histogram generation) should ideally be carried out at a single site.

Selective gray matter damage in neuropsychiatric lupus.

OBJECTIVE: Damage of brain parenchyma in patients with primary diffuse neuropsychiatric systemic lupus erythematosus (NPSLE) has been indicated by magnetization transfer imaging (MTI). However, the location of MTI abnormalities is unknown. This study was undertaken to assess the distribution of MTI abnormalities over gray matter (GM) and white matter (WM) in SLE patients with a history of NP symptoms without explanatory magnetic resonance imaging (MRI) evidence of focal disease. METHODS: MTI was performed in 24 female SLE patients with a history of diffuse NP symptoms and 24 healthy female controls. Magnetization transfer ratio (MTR) maps were calculated for GM and WM separately, and GM and WM MTR histograms were generated. Univariate and multivariate analyses with age as an additional covariate were performed on the histogram parameters peak location (PL), peak height (PH), and mean MTR. RESULTS: Compared with controls, significantly reduced PH (mean +/- SD 136 +/- 22 arbitrary units versus 151 +/- 13 arbitrary units) and mean MTR (33.3 +/- 1.0 percent units versus 33.6 +/- 0.5 percent units) were found in the GM of NPSLE patients (P = 0.002 and P = 0.033, respectively, in multivariate analyses). No significant differences were observed for WM MTR parameters. CONCLUSION: This is the first study to demonstrate, using MTI, that in SLE patients with a history of NP symptoms and without explanatory focal abnormalities on MRI, the GM is particularly affected. These findings support the hypothesis that neuronal injury may underlie central nervous system manifestations in NPSLE.

Multisequence magnetic resonance imaging study of neuropsychiatric systemic lupus erythematosus.

OBJECTIVE: To investigate the relationship between magnetization transfer imaging (MTI), diffusion-weighted imaging (DWI), proton magnetic resonance spectroscopy (H-MRS), and T2 relaxometry findings in patients with primary neuropsychiatric systemic lupus erythematosus (NPSLE). METHODS: The study group consisted of 24 female patients (mean age 36 years [range 23-65]) who had had a variety of neuropsychiatric symptoms that were judged to be due to NPSLE according to the criteria of the American College of Rheumatology. Patients with current active disease were excluded from participation. Quantitative MTI, DWI, H-MRS, and T2 relaxometry data were acquired in all patients, and the correlation coefficients were calculated. RESULTS: MTI results reflecting a decrease in homogeneity of cerebral parenchyma correlated significantly with H-MRS results representing axonal damage. MTI results also correlated significantly with DWI results reflecting increased diffusivity in the cerebral parenchyma. Finally, MTI results reflecting decreased cerebral homogeneity correlated significantly with increased T2 relaxation time, associated with either edema or gliosis. Increased T2 relaxation time correlated significantly with DWI results reflecting increased diffusivity. With the exception of the correlation between H-MRS and MTI findings, there was no significant correlation between H-MRS results and any other parameter. CONCLUSION: The selected study parameters represent different biologic features in the human brain and can be informative with regard to different pathologic processes in NPSLE. The demonstrated associations between MTI, DWI, H-MRS, and T2 data in patients with a history of NPSLE suggest that there is one pathogenesis and/or common neuropathologic outcome in NPSLE despite differences in clinical presentation.

A neuroimaging follow up study of a patient with juvenile central nervous system systemic lupus erythematosus.

BACKGROUND: The course of central nervous system systemic lupus erythematosus (CNS-SLE) is largely unknown. New imaging techniques are available to assist in monitoring the disease course. OBJECTIVE: To report a case of juvenile CNS-SLE, in which magnetic resonance imaging (MRI) was used to assess disease activity. CASE REPORT: A 10-year-old female patient with SLE presented with convulsions; MRI and computed tomography (CT) of the cerebrum disclosed abnormalities. Despite adequate treatment, two years later she had a generalised convulsion, and MRI showed new lesions. MR spectroscopy (MRS) indicated neuronal loss, inflammation, and metabolically compromised tissue; magnetisation transfer imaging (MTI) showed an increase in whole brain lesion load. After exclusion of a malignancy, CNS-SLE was the most likely diagnosis, and cyclophosphamide pulses were administered. Initially, multiple sclerosis (MS)-like lesions regressed, but despite maximal immunosuppressive drugs, new lesions formed and disappeared. When immunosuppressive drugs had been stopped for six months MRI showed improved lesions and MTI histograms. DISCUSSION: In this case report, the anatomical substrate, metabolic aspect, neuroimaging, and clinical course of MS-like lesions in a child with CNS-SLE are described. The way in which radiological techniques can support clinical decision making in this young patient with progressive CNS-SLE is illustrated.

Imaging modalities in central nervous system systemic lupus erythematosus.

Within the past few years, a clearly defined case definition system for central nervous system systemic lupus erythematosus (CNS-SLE) has been established. This has allowed cross-study comparisons of patients fulfilling the specific case definitions. New imaging techniques used on the subgroup of CNS-SLE patients that did not have any evidence for infarctions suggest that in these patients symptoms are associated with a diffuse process in the brain. Most likely this process leads to axonal damage and demyelination, ultimately leading to cerebral atrophy. With respect to the diagnostic work-up of SLE patients with neuropsychiatric symptoms, it has become clear that cranial magnetic resonance imaging is the technique of choice. Preliminary studies using quantitative magnetic resonance imaging techniques suggest that patients with neuropsychiatric symptoms caused by active CNS-SLE can be differentiated from patients with the same symptoms caused by residual disease.

Global estimation of myelination in the developing brain on the basis of magnetization transfer imaging: a preliminary study.

BACKGROUND AND PURPOSE: In the developing brain, myelination occurs in an orderly and predetermined sequence. The aim of this study was to determine whether such changes can be tracked using volumetric magnetization transfer imaging. METHODS: Three-dimensional magnetization transfer imaging was performed in 50 children (age range, 0.6-190 months) with no evidence of developmental delay or structural abnormalities. Volumetric magnetization transfer ratio (MTR) parameters generated of the whole brain were mean MTR and height and location of the MTR histogram peak. Relationships between volumetric MTR parameters and age were assessed using nonlinear regression analysis. RESULTS: With age, all volumetric MTR parameters changed exponentially in a way that was best expressed by the function y = a + b.exp(-x/c) (P < .0001). The peak height of the MTR histogram was the parameter that changed most predictably and that continued to change for the longest period of time. CONCLUSION: With this preliminary study, we show that by using volumetric MTR analysis, it is possible to monitor changes in the developing brain, presumably the myelination progress. This method has a potential role for detecting myelination disorders in the pediatric population, for studying the natural history of these diseases, and for monitoring the effects of treatment.