Advanced MRI Center: a 3 Tesla Magnetic Resonance system for preclinical, translational and clinical imaging studies

The Advanced MRI Center, located in the UMass Medical School building, is a research core facility providing the latest magnetic resonance imaging and spectroscopy capabilities to UMass scientists. It is equipped with a Philips Achieva 3.0T X-series whole-body scanner and radiofrequency coils for studying all organs of the human body, and small and large animals, such as mice, rats, rabbits, dogs, sheep and non-human primates. The center also includes a radiofrequency coil lab, a nurses’ station, two patient holding rooms and two patient changing rooms. The Center’s specialized techniques are able to elucidate functional, physiological and biochemical information from all organs of the body. The 3.0 Tesla system features the Quasar Dual gradient system with industry leading performance specifications, that allow high-level diffusion tensor imaging and functional MRI (fMRI) applications in humans, and high resolution imaging studies in small animal studies. A fMRI stimulus delivery system, a MRI compatible goggle set with eye tracking system, microphone and earphones are available for facilitating fMRI studies. Small animal monitoring and gating system and an MR compatible Anesthesia system with heater and ventilator option are also available. The 3.0T MR system is also equipped with a Multi-nuclear spectroscopy system, which provide the ability to perform 13C, 31P, 7Li, 23Na and other nuclei spectroscopy and imaging. Technical and clinical expertise for collaborative research is also provided

442. LV Expressing MR Reporter Genes Allows In Vivo Monitoring of Stem Cell Gene Therapy

Somatic stem cells (SSC) have raised interest because of their therapeutic potential in both cell-based and gene therapy applications. Towards this goal, tracking the fate of either delivered cells or of genetically modified endogenous cells is of utmost importance. Diverse imaging approaches are available for cell tracking and among these MRI shows a greater resolution and allows direct anatomic correlation and long-term studies of dynamic cell migration on living animals. Superparamagnetic iron oxide (SPIO) has been used to label SSC in vitro and to make them detectable in vivo upon transplantation. However, major limitations of this approach are the progressive dilution of the contrast media among cell progeny and the need for ex vivo SPIO loading. We thus explored an alternative strategy based on the combination of lentiviral vectors (LV), which efficiently transduce SSC both ex vivo and in vivo and allow long-term expression in their progeny, and MR reporter genes, able to increase iron uptake and accumulation into different cell types

Development and validation of a new MRI simulation technique that can reliably estimate optimal in vivo scanning parameters in a glioblastoma murine model

BACKGROUND: Magnetic Resonance Imaging (MRI) relies on optimal scanning parameters to achieve maximal signal-to-noise ratio (SNR) and high contrast-to-noise ratio (CNR) between tissues resulting in high quality images. The optimization of such parameters is often laborious, time consuming, and user-dependent, making harmonization of imaging parameters a difficult task. In this report, we aim to develop and validate a computer simulation technique that can reliably provide optimal in vivo scanning parameters ready to be used for in vivo evaluation of disease models. METHODS: A glioblastoma murine model was investigated using several MRI imaging methods. Such MRI methods underwent a simulated and an in vivo scanning parameter optimization in pre- and post-contrast conditions that involved the investigation of tumor, brain parenchyma and cerebrospinal fluid (CSF) CNR values in addition to the time relaxation values of the related tissues. The CNR tissues information were analyzed and the derived scanning parameters compared in order to validate the simulated methodology as a reliable technique for optimal in vivo scanning parameters estimation. RESULTS: The CNRs and the related scanning parameters were better correlated when spin-echo-based sequences were used rather than the gradient-echo-based sequences due to augmented inhomogeneity artifacts affecting the latter methods. Optimal in vivo scanning parameters were generated successfully by the simulations after initial scanning parameter adjustments that conformed to some of the parameters derived from the in vivo experiment. CONCLUSION: Scanning parameter optimization using the computer simulation was shown to be a valid surrogate to the in vivo approach in a glioblastoma murine model yielding in a better delineation and differentiation of the tumor from the contralateral hemisphere. In addition to drastically reducing the time invested in choosing optimal scanning parameters when compared to an in vivo approach, this simulation program could also be used to harmonize MRI acquisition parameters across scanners from different vendors

MRI Evidence of Cerebellar and Extraocular Muscle Atrophy Differently Contributing to Eye Movement Abnormalities in SCA2 and SCA28 Diseases.

PURPOSE Spinocerebellar ataxias type 2 and 28 (SCA2, SCA28) are autosomal dominant disorders characterized by progressive cerebellar and oculomotor abnormalities. We aimed to investigate cerebellar, brainstem, and extraocular muscle involvement in the mitochondrial SCA28 disease compared with SCA2. METHODS We obtained orbital and brain 1.5 T-magnetic resonance images (MRI) in eight SCA28 subjects, nine SCA2, and nine age-matched healthy subjects. Automated segmentation of cerebellum and frontal lobe was performed using Freesurfer software. Manual segmentations for midbrain, pons, and extraocular muscles were performed using OsiriX. RESULTS Eye movement abnormalities in SCA2 subjects were characterized by slow horizontal saccades. Subjects with SCA28 variably presented hypometric saccades, saccadic horizontal pursuit, impaired horizontal gaze holding, and superior eyelid ptosis. Quantitative brain MRI demonstrated that cerebellar and pons volumes were significantly reduced in both SCA2 and SCA28 subjects compared with controls (P < 0.03), and in SCA2 subjects compared with SCA28 (P < 0.01). Midbrain and frontal lobe volumes were also significantly reduced in SCA2 compared to controls (P < 0.03), whereas these volumes did not differ between SCA2 and SCA28 and between SCA28 and control subjects. The extraocular muscle areas were 37% to 48% smaller in SCA28 subjects compared with controls (P < 0.002), and 14% to 36% smaller compared with SCA2 subjects (P < 0.03). Extraocular muscle areas did not differ between SCA2 and controls. CONCLUSIONS Our MRI findings support the hypothesis of different cerebellar and extraocular myopathic contributions in the eye movement abnormalities in SCA2 and SCA28 diseases. In SCA28, a myopathic defect selectively involving the extraocular muscles supports a specific impairment of mitochondrial energy metabolism

Quantitative MRI Harmonization to Maximize Clinical Impact: The RIN-Neuroimaging Network

Neuroimaging studies often lack reproducibility, one of the cardinal features of the scientific method. Multisite collaboration initiatives increase sample size and limit methodological flexibility, therefore providing the foundation for increased statistical power and generalizable results. However, multisite collaborative initiatives are inherently limited by hardware, software, and pulse and sequence design heterogeneities of both clinical and preclinical MRI scanners and the lack of benchmark for acquisition protocols, data analysis, and data sharing. We present the overarching vision that yielded to the constitution of RIN-Neuroimaging Network, a national consortium dedicated to identifying disease and subject-specific in-vivo neuroimaging biomarkers of diverse neurological and neuropsychiatric conditions. This ambitious goal needs efforts toward increasing the diagnostic and prognostic power of advanced MRI data. To this aim, 23 Italian Scientific Institutes of Hospitalization and Care (IRCCS), with technological and clinical specialization in the neurological and neuroimaging field, have gathered together. Each IRCCS is equipped with high- or ultra-high field MRI scanners (i.e., ≥3T) for clinical or preclinical research or has established expertise in MRI data analysis and infrastructure. The actions of this Network were defined across several work packages (WP). A clinical work package (WP1) defined the guidelines for a minimum standard clinical qualitative MRI assessment for the main neurological diseases. Two neuroimaging technical work packages (WP2 and WP3, for clinical and preclinical scanners) established Standard Operative Procedures for quality controls on phantoms as well as advanced harmonized quantitative MRI protocols for studying the brain of healthy human participants and wild type mice. Under FAIR principles, a web-based e-infrastructure to store and share data across sites was also implemented (WP4). Finally, the RIN translated all these efforts into a large-scale multimodal data collection in patients and animal models with dementia (i.e., case study). The RIN-Neuroimaging Network can maximize the impact of public investments in research and clinical practice acquiring data across institutes and pathologies with high-quality and highly-consistent acquisition protocols, optimizing the analysis pipeline and data sharing procedures

The Radiology Department during the COVID-19 pandemic: a challenging, radical change

Since the first cases of SARS-CoV-2 pneumonia reported in Wuhan in December 2019, the Coronavirus Disease 2019 (COVID-19) has rapidly spread worldwide, and Radiology Departments have to face significant changes in order to cope with this sanitary emergency. We would like to share our experience with the outbreak of COVID-19 in our Radiology Department at the Humanitas Clinical and Research University Hospital, a tertiary level center located in Milan, Italy. In particular, we would like to share some actions we undertook in our activities that other Radiology Departments might ponder to take into consideration

Metachromatic Leukodystrophy: Too Frequent (Mis)Diagnosis

Recently, Wu et al1 reported the case of an adult patient with late-onset cobalamin C disease who received an incorrect diagnosis of adult metachromatic leukodystrophy (MLD). In this patient, the disease onset was characterized by acute psychiatric symptoms and spastic paraparesis. A brain magnetic resonance imagining (MRI) scan performed 2 months after the onset showed an area of hyperintensity on fluid-attenuated inversion recovery images in the right occipital subcortical white matter. The involvement of bilateral occipital white matter and centrum semiovale was evident at a follow-up MRI that was performed 21 months after the onset. At this time, arylsulfatase A (ARSA) enzyme activity was tested in peripheral blood leukocytes, and the results showed that the levels were half of the normal lower limit. Metachromatic leukodystrophy was suspected and the patient underwent genetic testing. This is an interesting case, but in our opinion, it is confounding to emphasize MLD in the differential diagnosis because it could have been ruled out much sooner