Carmela Russo

In vivo dentate nucleus MRI relaxometry correlates with previous administration of Gadolinium-based contrast agents

AbstractObjectivesTo evaluate changes in T1 and T2* relaxometry of dentate nuclei (DN) with respect to the number of previous administrations of Gadolinium-based contrast agents (GBCA).MethodsIn 74 relapsing-remitting multiple sclerosis (RR-MS) patients with variable disease duration (9.8±6.8 years) and severity (Expanded Disability Status Scale scores:3.1±0.9), the DN R1 (1/T1) and R2* (1/T2*) relaxation rates were measured using two unenhanced 3D Dual-Echo spoiled Gradient-Echo sequences with different flip angles. Correlations of the number of previous GBCA administrations with DN R1 and R2* relaxation rates were tested, including gender and age effect, in a multivariate regression analysis.ResultsThe DN R1 (normalized by brainstem) significantly correlated with the number of GBCA administrations (p<0.001), maintaining the same significance even when including MS-related factors. Instead, the DN R2* values correlated only with age (p=0.003), and not with GBCA administrations (p=0.67). In a subgroup of 35 patients for whom the administered GBCA subtype was known, the effect of GBCA on DN R1 appeared mainly related to linear GBCA.ConclusionsIn RR-MS patients, the number of previous GBCA administrations correlates with R1 relaxation rates of DN, while R2* values remain unaffected, suggesting that T1-shortening in these patients is related to the amount of Gadolinium given.Key Points• In multiple sclerosis, previous Gadolinium administrations correlate with dentate nuclei T1 relaxometry. • Such correlation is linked to linear Gadolinium chelates and unrelated to disease duration or severity. • Dentate nuclei T2* relaxometry is age-related and independent of previous Gadolinium administrations. • Changes in dentate nuclei T1 relaxometry are not determined by iron accumulation. • MR relaxometry can quantitatively assess Gadolinium accumulation in dentate nuclei.

The Framingham cardiovascular risk score in multiple sclerosis.

Cardiovascular risk factors can increase the risk of multiple sclerosis (MS) and modify its course. However, such factors possibly interact, determining a global cardiovascular risk. Our aim was to compare the global cardiovascular risk of subjects with and without MS with the simplified 10‐year Framingham General Cardiovascular Disease Risk Score (FR) and to evaluate its importance on MS‐related outcomes.

Unilateral proptosis in thyroid eye disease with subsequent contralateral involvement: retrospective follow-up study

BackgroundThe purpose of this retrospective follow-up study is to evaluate the prevalence of patients with thyroid eye disease presenting with apparent unilateral proptosis and determine the occurrence of exophthalmos in contralateral non-proptotic eye over the time. Associated features with this event were evaluated.MethodsA cohort of 655 consecutive patients affected by thyroid eye disease with a minimum follow-up of 10 years was reviewed. Exophthalmos was assessed by using both Hertel exophthalmometer and computed tomography (CT). The influence of age, gender, hormonal status and of different therapies such as corticosteroids, radiotherapy and surgical decompression on this disease progression was evaluated.ResultsA total of 89 patients (13.5%) (95% confidence interval [CI] 15%-10%) had clinical evidence of unilateral exophthalmos at the first visit. Among these, 13 patients (14%) (95% CI 22%-7%) developed subsequent contralateral exophthalmos. The increase of protrusion ranged from 2 to 7 mm (mean of 4.2). The time of onset varied from 6 months to 7 years (mean time: 29 months). Smoking status, young age and surgical decompression are significantly associated with development of contralateral proptosis (p< .05).ConclusionsAsymmetric thyroid eye disease with the appearance of unilateral exophthalmos at the initial examination is a fairly frequent event, while subsequent contralateral proptosis occurs less commonly. However, physicians should be aware that young patients, particularly if smokers, undergoing orbital decompression in one eye may need further surgery on contralateral side over time.

A Novel Multiparametric Approach to 3D Quantitative MRI of the Brain.

Magnetic Resonance properties of tissues can be quantified in several respects: relaxation processes, density of imaged nuclei, magnetism of environmental molecules, etc. In this paper, we propose a new comprehensive approach to obtain 3D high resolution quantitative maps of arbitrary body districts, mainly focusing on the brain. The theory presented makes it possible to map longitudinal (R 1), pure transverse (R 2) and free induction decay (R2*) rates, along with proton density (PD) and magnetic susceptibility (χ), from a set of fast acquisition sequences in steady-state that are highly insensitive to flow phenomena. A novel denoising scheme is described and applied to the acquired datasets to enhance the signal to noise ratio of the derived maps and an information theory approach compensates for biases from radio frequency (RF) inhomogeneities, if no direct measure of the RF field is available. Finally, the results obtained on sample brain scans of healthy controls and multiple sclerosis patients are presented and discussed.

Diffusion Weighted MR Imaging of Primary and Recurrent Middle Ear Cholesteatoma: An Assessment by Readers with Different Expertise

Introduction and Purpose. Diffusion weighted imaging (DWI) has been proven to be valuable in the diagnosis of middle ear cholesteatoma. The aims of our study were to evaluate the advantage of multi-shot turbo spin echo (MSh TSE) DWI compared to single-shot echo-planar (SSh EPI) DWI for the diagnosis of cholesteatoma. Material and Methods. Thirty-two patients with clinical suspicion of unilateral cholesteatoma underwent preoperative MRI (1.5T) with SSh EPI and MSh TSE. Images were separately analyzed by 4 readers with different expertise to confirm the presence of cholesteatoma. Sensitivity, specificity, diagnostic accuracy, and positive (PPV) and negative predictive values (NPV) were assessed for each observer and interrater agreement was assessed using kappa statistics. Diagnosis was obtained at surgery. Results. Overall MSh TSE showed higher diagnostic accuracy and lower negative predictive value (NPV) compared to conventional SSh EPI. Interreader agreement between the observers revealed the superiority of MSh TSE compared to SSh EPI. Interrater agreement among all the four observers was higher by using MSh TSE compared to SSh EPI. Conclusion. Our findings suggest that MSh TSE DWI has higher sensitivity for detection of cholesteatoma and lower probability of misdiagnosis. MSh TSE DWI is useful in guiding less experienced observers to the diagnosis.

MRI Features of Spinal Solitary Fibrous Tumors A Report of Two Cases and Literature Review

Spinal solitary fibrous tumors (SFT) are very rare neoplasms occurring in the spinal canal, with only 38 cases reported in ten years since the first description. We describe two cases of SFT of the spine and review 33 well-documented cases in the literature to define distinctive radiological and surgical features raising the suspicion of a spinal SFT before histological verification. A 67-year-old man with cervical myeloradiculopathy had a large extramedullary tumor of the cervical spinal canal extending from C4 to C7. On MRI the tumor was isointense on T1-sequences and hypointense on T2-sequences, and had marked contrast enhancement. At surgery, the tumor was intradural extramedullary, with no dural or root attachment, but it was adherent to the cord. Complete tumor removal was achieved with good outcome. A 75-year-old man with progressive thoracic myelopathy had an intramedullary tumor at C6 and C7 level, which was hypointense on T1- and T2-weighted images of MRI. At surgery, the tumor was intramedullary and strongly adherent to the cord; it was successfully removed. Both tumors were composed of elongated cells with a collagen-matrix background. Immunohistochemical staining was positive for vimentin, CD34, and bcl-2, and negative for EMA and S-100 protein. A careful analysis of our own and the other reported cases of spinal SFTs may disclose some peculiar features of this rare tumor. A spinal intramedullary or extramedullary tumor, hypointense on T2-weighted images of MRI, which intraoperatively shows hard consistency, scarce vascularization, no nerve root involvement, no or weak dural attachment, absence of arachnoidal interface, and adherence to the spinal cord may suggest the diagnosis of SFT.

The “eye of the tiger” sign in pure akinesia with gait freezing

The “eye of the tiger” is a neuroradiologic sign due to iron deposition in the globus pallidus: it appears as diffuse low signal intensity with a central area of high signal intensity confined to the globus pallidus. The “eye of the tiger” sign has been associated with neurodegeneration with brain iron accumulation type 1 (NBIA1), a condition caused by mutations in the gene encoding pantothenate kinase 2 (PANK2). However, the specificity of this neuroradiologic sign has been already challenged and it has been described in other neurodegenerative diseases. Here, we report the first case of a patient suffering from pure akinesia with gait freezing with the “eye of the tiger” sign in T2-weighted MRI sequences. All clinical, laboratory and radiologic data excluded other diagnosis and genetic testing excluded PANK2 mutations suggesting that the “eye of the tiger” is not specific for NBIA1 and may also occur in other movement disorders.

Redefining the Pulvinar Sign in Fabry Disease

BACKGROUND AND PURPOSE: The pulvinar sign refers to exclusive T1WI hyperintensity of the lateral pulvinar. Long considered a common sign of Fabry disease, the pulvinar sign has been reported in many pathologic conditions. The exact incidence of the pulvinar sign has never been tested in representative cohorts of patients with Fabry disease. The aim of this study was to assess the prevalence of the pulvinar sign in Fabry disease by analyzing T1WI in a large Fabry disease cohort, determining whether relaxometry changes could be detected in this region independent of the pulvinar sign positivity. MATERIALS AND METHODS: We retrospectively analyzed brain MR imaging of 133 patients with Fabry disease recruited through specialized care clinics. A subgroup of 26 patients underwent a scan including 2 FLASH sequences for relaxometry that were compared with MRI scans of 34 healthy controls. RESULTS: The pulvinar sign was detected in 4 of 133 patients with Fabry disease (3.0%). These 4 subjects were all adult men (4 of 53, 7.5% of the entire male population) with renal failure and under enzyme replacement therapy. When we tested for discrepancies between Fabry disease and healthy controls in quantitative susceptibility mapping and relaxometry maps, no significant difference emerged for any of the tested variables. CONCLUSIONS: The pulvinar sign has a significantly lower incidence in Fabry disease than previously described. This finding, coupled with a lack of significant differences in quantitative MR imaging, allows hypothesizing that selective involvement of the pulvinar is a rare neuroradiologic sign of Fabry disease.

Improving SNR in Susceptibility Weighted Imaging by a NLM-based denoising scheme

The combination of magnitude and phase information inherent in Susceptibility-Weighted Imaging (SWI) greatly benefits from high-resolution MRI acquisitions. The application of a denoising filter to produce SWI images with higher signal-to-noise ratio (SNR) while preserving small structures from excessive blurring is therefore extremely desirable, but non-trivial, as the distribution of magnitude and phase noise may introduce biases during image restoration. Here we present a new dedicated noise removal algorithm based on the Non-Local Means (NLM) filter and compare its results with the original SWI and “standard” NLM-denoised human brain images. Both the visual assessment by two expert readers and the quantitative evaluation of the contrast changes of the voxel intensities demonstrated that the images restored with the proposed algorithm fared consistently better than the other two schemes, showing that a proper handling of noise in the complex MRI dataset may lead to visible improvements of the overall SWI quality.

Coexistence of cavernous hemangioma and other vascular malformations of the orbit. A report of three cases.

Coexistence of orbital cavernous hemangioma and other vascular malformations is unusual and few cases have been reported. We describe the clinical and radiological features of three cases of orbital cavernous hemangiomas associated with other vascular malformations, selected reviewing a series of 181 cases of cavernous hemangiomas. All patients were males (age ranging from 43 to 67 years) without vascular systemic disorders and/or a clinical syndrome. They experienced slow progressive exophthalmos. One of them developed acute pulsatile proptosis (case 2), while another experienced slow progressive diplopia (case 3). In one case vascular lesions were bilateral (case 3) and in two patients two different lesions coexisted in the same orbit (cases 1 and 2). All patients underwent surgical excision, which was partial in two cases. Two patients had cavernous hemangiomas in association with a venous malformation (a varix in case 1 and a lymphangioma in case 2), while in the other ones (case 3) cavernous hemangioma was associated with a low-flow arteriovenous malformation. No patient denied visual impairment postoperatively. Few cases of orbital cavernous hemangiomas coexisting with other vascular malformations have been reported in the literature. This entity seems to be an association of different variants of orbital vascular malformations, presenting with a wide spectrum of clinical forms and probably with the same pathogenesis.