Real-word application of the AT(N) classification and disease-modifying treatment eligibility in a hospital-based cohort.

BACKGROUND AND OBJECTIVES: The AT(N) classification system stratifies patients based on biomarker profiles, including amyloid-beta deposition (A), tau pathology (T), and neurodegeneration (N). This study aims to apply the AT(N) classification to a hospital-based cohort of patients with cognitive decline and/or dementia, within and outside the Alzheimer's disease (AD) continuum, to enhance our understanding of the multidimensional aspects of AD and related disorders. Furthermore, we wish to investigate how many cases from our cohort would be eligible for the available disease modifying treatments, such as aducanemab and lecanemab. METHODS: We conducted a retrospective evaluation of 429 patients referred to the Memory Center of IRCCS San Raffaele Hospital in Milan. Patients underwent clinical/neuropsychological assessments, lumbar puncture, structural brain imaging, and positron emission tomography (FDG-PET). Patients were stratified according to AT(N) classification, group comparisons were performed and the number of eligible cases for anti-ß amyloid monoclonal antibodies was calculated. RESULTS: Sociodemographic and clinical features were similar across groups. The most represented group was A + T + N + accounting for 38% of cases, followed by A + T - N + (21%) and A - T - N + (20%). Although the clinical presentation was similar, the A + T + N + group showed more severe cognitive impairment in memory, language, attention, executive, and visuospatial functions compared to other AT(N) groups. Notably, T + patients demonstrated greater memory complaints compared to T - cases. FDG-PET outperformed MRI and CT in distinguishing A + from A - patients. Although 61% of the observed cases were A + , only 17% of them were eligible for amyloid-targeting treatments. DISCUSSION: The AT(N) classification is applicable in a real-world clinical setting. The classification system provided insights into clinical management and treatment strategies. Low cognitive performance and specific regional FDG-PET hypometabolism at diagnosis are highly suggestive for A + T + or A - T + profiles. This work provides also a realistic picture of the proportion of AD patients eligible for disease modifying treatments emphasizing the need for early detection.

Combining semi-quantitative rating and automated brain volumetry in MRI evaluation of patients with probable behavioural variant of fronto-temporal dementia: an added value for clinical practise?

PURPOSE: To evaluate the diagnostic value of combined semiquantitative and quantitative assessment of brain atrophy in the diagnostic workup of the behavioural-variant of frontotemporal dementia (bvFTD). METHODS: Three neuroradiologists defined brain atrophy grading and identified atrophy pattern suggestive of bvFTD on 3D-T1 brain MRI of 112 subjects using a semiquantitative rating scale (Kipps'). A quantitative atrophy assessment was performed using two different automated software (Quantib® ND and Icometrix®). A combined semiquantitative and quantitative assessment of brain atrophy was made to evaluate the improvement in brain atrophy grading to identify probable bvFTD patients. RESULTS: Observers' performances in the diagnosis of bvFTD were very good for Observer 1 (k value = 0.881) and 2 (k value = 0.867), substantial for Observer 3 (k value = 0.741). Semiquantitative atrophy grading of all the observers showed a moderate and a poor correlation with the volume values calculated by Icometrix® and by Quantib® ND, respectively. For the definition of neuroradiological signs presumptive of bvFTD, the use of Icometrix® software improved the diagnostic accuracy for Observer 1 resulting in an AUC of 0.974, and for Observer 3 resulting in a AUC of 0.971 (p-value < 0.001). The use of Quantib® ND software improved the diagnostic accuracy for Observer 1 resulting in an AUC of 0.974, and for Observer 3 resulting in a AUC of 0.977 (p-value < 0.001). No improvement was observed for Observer 2. CONCLUSION: Combining semiquantitative and quantitative brain imaging evaluation allows to reduce discrepancies in the neuroradiological diagnostic workup of bvFTD by different readers.

Neural stem cell transplantation in patients with progressive multiple sclerosis: an open-label, phase 1 study.

Innovative pro-regenerative treatment strategies for progressive multiple sclerosis (PMS), combining neuroprotection and immunomodulation, represent an unmet need. Neural precursor cells (NPCs) transplanted in animal models of multiple sclerosis have shown preclinical efficacy by promoting neuroprotection and remyelination by releasing molecules sustaining trophic support and neural plasticity. Here we present the results of STEMS, a prospective, therapeutic exploratory, non-randomized, open-label, single-dose-finding phase 1 clinical trial ( NCT03269071 , EudraCT 2016-002020-86), performed at San Raffaele Hospital in Milan, Italy, evaluating the feasibility, safety and tolerability of intrathecally transplanted human fetal NPCs (hfNPCs) in 12 patients with PMS (with evidence of disease progression, Expanded Disability Status Scale ≥6.5, age 18-55 years, disease duration 2-20 years, without any alternative approved therapy). The safety primary outcome was reached, with no severe adverse reactions related to hfNPCs at 2-year follow-up, clearly demonstrating that hfNPC therapy in PMS is feasible, safe and tolerable. Exploratory secondary analyses showed a lower rate of brain atrophy in patients receiving the highest dosage of hfNPCs and increased cerebrospinal fluid levels of anti-inflammatory and neuroprotective molecules. Although preliminary, these results support the rationale and value of future clinical studies with the highest dose of hfNPCs in a larger cohort of patients.

Imaging characterization of an adult H3 K27M-altered diffuse midline glioma of the medulla oblongata with a confounding steroid response.

We report an uncommon, infratentorial localization of adult H3 K27M-altered diffuse midline glioma arising in a particularly rare site (medulla oblongata). In addition to this unusual presentation, the lesion exhibited a substantial contrast enhancement and size decrease after dexamethasone, generating diagnostic dilemmas. Histology, molecular details, advanced Magnetic Resonance imaging features and differential diagnoses are here described and discussed, as well as common misconceptions about steroid-sensitive mass lesions, and practical difficulties for clinicians involved in the process of making diagnosis.

Amyloid-Related Imaging Abnormalities and ß-Amyloid-Targeting Antibodies: A Systematic Review.

IMPORTANCE: After more than a decade of research and development of clinical trials testing anti-ß-amyloid monoclonal antibodies (mAbs), extensive experience has been gained regarding the effects of these treatments in patients with Alzheimer disease (AD). On the verge of an expected large-scale introduction in the clinical setting after the recent US Food and Drug Administration approval of aducanumab, shared knowledge regarding amyloid-related imaging abnormalities (ARIAs) is of paramount importance. OBJECTIVE: To summarize available evidence on ARIAs from randomized clinical trials (RCTs) testing anti-ß-amyloid mAbs in patients with AD and to provide a comprehensive update about risk factors, clinical correlates, and implications for withholding and reinitiating treatment. EVIDENCE REVIEW: In this systematic review, a literature search of MEDLINE/PubMed, Embase, and Cochrane Library and a search of ClinicalTrials.gov were conducted through September 15, 2021. Publications describing RCTs, secondary analyses of RCT data, and case reports of ARIAs were included. Strengths of clinical data were graded according to the Oxford Centre for Evidence-Based Medicine. FINDINGS: Twenty-two RCTs, 11 secondary analyses of RCTs, and 1 case report, including in total 15 508 adult patients (8483 women [54.7%]; mean [SD] age, 69.6 [8.3] years) were selected for inclusion. Signal alterations that included parenchymal edema and sulcal effusion leading to transient hyperintensities on fluid-attenuated inversion recovery and T2-weighted sequences were termed ARIA-E, whereas those consisting of hemosiderin deposits, including parenchymal microhemorrhages and leptomeningeal superficial siderosis, were termed ARIA-H. Apolipoprotein E (ApoE) ε4 genotype was the main risk factor for both ARIA types; ARIA-E incidence was further associated with treatment dose, affecting the 55% of ApoE ε4 carriers in the high-dose aducanumab treatment group. Both ARIA types manifested early during study course, and symptomatic cases accounted for the 6.1% to 39.3% of ARIA-E cases at higher treatment doses across RCTs, whereas ARIA-H cases were generally asymptomatic. Most ARIA-E cases resolved with treatment withholding, although corticosteroid administration was required anecdotally. ARIA-E recurrence after dose reinitiation or adjustment varied from 13.8% to 25.6% across RCTs. CONCLUSIONS AND RELEVANCE: Evidence suggests that ARIAs are frequent, mostly asymptomatic collateral events of amyloid-modifying therapies, highlighting the need for standardized clinical and neuroradiological management protocols in real-world clinical settings.

Diagnostic efficacy and safety of gadoteridol compared to gadobutrol and gadoteric acid in a large sample of CNS MRI studies at 1.5T.

PURPOSE: To evaluate safety and diagnostic accuracy of gadoteridol vs. other macrocyclic gadolinium-based contrast agents (GBCAs) in a large cohort of consecutive and non-selected patients referred for CE-MRI of the CNS. MATERIAL AND METHODS: Between November 2017 and March 2018, we prospectively enrolled a consecutive cohort of patients referred for neuroradiological CE-MRI (1.5T MRI). Image quality and adverse events were assessed. Diagnostic performance was determined for a subgroup of patients with truth standard findings available. Comparison was made between patients receiving gadoteridol and patients receiving other macrocyclic GBCAs. Inter-reader agreement (kappa) between two expert neuroradiologists was calculated for the diagnosis of malignancy. RESULTS: Overall, 460 patients (220M/240F; mean age 54±16 years) were enrolled of which 230 received gadoteridol (Group 1) and 230 either gadoteric acid or gadobutrol [n=83 (36.1%) and n=147 (63.9%), respectively; Group 2]. Image quality was rated as good or excellent in both groups. The sensitivity, specificity and diagnostic accuracy for determination of malignancy was 88.2%, 96.5% and 95.4%, respectively, for Group 1 and 93.7%, 97.4% and 96.9%, respectively, for Group 2, with no significant differences between groups (P>0.75) for any determination. Inter-reader agreement for the identification of malignancy was excellent [K=0.877 (95%CI: 0.758-0.995) and K=0.818 (95%CI: 0.663-0.972) for groups 1 and 2, respectively; P=0.0913]. Adverse events occurred in 5 of 460 (1.09%) patients overall, with no significant difference (P=0.972) between groups. CONCLUSION: Gadoteridol was safe and guaranteed good image quality without significant differences when compared to gadobutrol and gadoteric acid in a wide range of CNS pathologies.

Breakthrough Invasive Fungal Infections in Allogeneic Hematopoietic Stem Cell Transplantation.

Despite the recent introduction of mold-active antifungal prophylaxis (MAP), breakthrough invasive fungal infections (b-IFI) still represent a possible complication and a cause of morbidity and mortality in hematological patients and allogeneic hematopoietic stem-cell transplantation recipients (HSCT). Data on incidence and type of b-IFI are limited, although they are mainly caused by non-fumigatus Aspergillus and non-Aspergillus molds and seem to depend on specific antifungal prophylaxis and patients' characteristics. Herein, we described the clinical presentation and management of two cases of rare b-IFI which recently occurred at our institution in patients undergoing HSCT and receiving MAP. The management of b-IFI is challenging due to the lack of data from prospective trials and high mortality rates. A thorough analysis of risk factors, ongoing antifungal prophylaxis, predisposing conditions and local epidemiology should drive the choice of antifungal treatments. Early broad-spectrum preemptive therapy with a lipid formulation of amphotericin-B, in combination with a different mold-active azole plus/minus terbinafine, is advisable. The therapy would cover against rare azole-susceptible and -resistant fungal strains, as well as atypical sites of infections. An aggressive diagnostic work-up is recommended for species identification and subsequent targeted therapy.

The role of CE-MRA of the supraortic vessels in the detection of associated intracranial pathology.

BACKGROUND: Contrast-enhanced magnetic resonance angiography (CE-MRA) has become a very popular imaging technique in the evaluation of the extracranial vessels pathology, while it is not commonly used to rule out intracranial vascular pathology. On the contrary, 3D time of flight MRA (TOF-MRA) has a solid role in the study of intracranial arterial vessels disease. MATERIALS AND METHODS: One hundred and eight patients were consecutively included in the study. All patients were submitted to a 3 Tesla 3D CE-MRA imaging to rule out extracranial vessels pathology. A comparison was made with a 3D-TOF sequence acquired at the same time in the assessment of intracranial vessels diseases such as steno-occlusion, dissection, and aneurysms. RESULTS: With regard to steno-occlusive disease, Spearman's rank correlation coefficient was of 0.56 for stenosis detection and of 0.57 for occlusive disease detection. The two techniques shared similar results in the evaluation of anterior circulation, while 3D-TOF found higher grades of stenosis for posterior circulation. With regard to dissection, Spearman's rank correlation coefficient was of 0.7. 3D-TOF depicted more intramural hematoma (Spearman's rank = 0.46), while CE-MRA showed more pseudo-aneurysms (Spearman's rank = 0.56). Both the technique equally evaluated the presence of intracranial aneurysms (Spearman's rank = 1). CONCLUSION: CE-MRA can be considered a reliable tool to rule out intracranial pathology associated to supraortic steno-occlusive disease, also allowing time reduction. In the suspicion of dissection a T1-weighted sequence has to be added to detect the presence of a subacute vessel wall hematoma.

First-in-Man Study Evaluating the Emblok Embolic Protection System During Transcatheter Aortic Valve Replacement.

OBJECTIVES: This study sought to evaluate the feasibility of complete cerebral protection during transcatheter aortic valve replacement (TAVR) with a novel embolic protection device. BACKGROUND: Evidences and data about new cerebral embolic protection devices are lacking and scarce. METHODS: A prospective, nonrandomized, multicenter, first-in-man pilot study designed to evaluate the efficacy and safety of cerebral embolic protection utilizing the Emblok embolic protection system (Innovative Cardiovascular Solutions, Grand Rapids, Michigan) during TAVR. The Emblok is a transfemoral aortic filter that provide full coverage of the epiaortic vessels. Brain diffusion-weighted magnetic resonance imaging (DW-MRI) was performed at baseline and 2 to 5 days after TAVR. Primary endpoints were technical success and immediate cerebral embolic burden after TAVR, defined as number and volume of new brain lesions detected with DW-MRI at days 2 to 5 post-TAVR compared with baseline. RESULTS: A total of 20 subjects were enrolled. The Emblok system was successfully positioned in all the cases. At 30-day follow-up, no major adverse cardiovascular and cerebrovascular events occurred. Nineteen (95%) patients had new ischemic defects at post-procedural DW-MRI. The median number of new lesions per patient was 10.00 (interquartile range [IQR]: 4.75 to 15.25). The total new lesion volume was 199.9 mm3 (IQR: 83.9 to 447.5 mm3) and the mean lesion volume per lesion was 42.5 mm3 (IQR: 21.5 to 75.6 mm3). Histopathologic analysis showed evidence of significant debris in 18 (90%) filters. CONCLUSIONS: The Emblok embolic protection system appears to be feasible and safe during TAVR. The device was successfully placed and retrieved in all cases and no neurological events were observed. Cerebral total new lesion volume was similar to other trials on cerebral protection during TAVR, thus warranting a larger study. (European Study Evaluating the Emblok Embolic Protection System During TAVR; NCT03130491).

Islet transplantation stabilizes hemostatic abnormalities and cerebral metabolism in individuals with type 1 diabetes.

OBJECTIVE Islets after kidney transplantation have been shown to positively affect the quality of life of individuals with type 1 diabetes (T1D) by reducing the burden of diabetes complications, but fewer data are available for islet transplantation alone (ITA). The aim of this study was to assess whether ITA has a positive impact on hemostatic and cerebral abnormalities in individuals with T1D. RESEARCH DESIGN AND METHODS Prothrombotic factors, platelet function/ultrastructure, and cerebral morphology, metabolism, and function have been investigated over a 15-month follow-up period using ELISA/electron microscopy and magnetic resonance imaging, nuclear magnetic resonance spectroscopy, and neuropsychological evaluation (Profile of Mood States test and paced auditory serial addition test) in 22 individuals with T1D who underwent ITA (n = 12) or remained on the waiting list (n = 10). Patients were homogeneous with regard to metabolic criteria, hemostatic parameters, and cerebral morphology/metabolism/function at the time of enrollment on the waiting list. RESULTS At the 15-month follow-up, the group undergoing ITA, but not individuals with T1D who remained on the waiting list, showed 1) improved glucose metabolism; 2) near-normal platelet activation and prothrombotic factor levels; 3) near-normal cerebral metabolism and function; and 4) a near-normal neuropsychological test. CONCLUSIONS ITA, despite immunosuppressive therapy, is associated with a near-normalization of hemostatic and cerebral abnormalities.

Allogeneic hematopoietic stem cell transplantation for neuromyelitis optica.

Neuromyelitis optica is a rare neurological autoimmune disorder characterized by a poor prognosis. Immunosuppression can halt disease progression, but some patients are refractory to multiple treatments, experiencing frequent relapses with accumulating disability. Here we report on durable clinical remissions after allogeneic hematopoietic stem cell transplantation in 2 patients suffering from severe forms of the disease. Immunological data evidenced disappearance of the pathogenic antibodies and regeneration of a naive immune system of donor origin. These findings correlated with evident clinical and radiological improvement in both patients, warranting extended clinical trials to investigate this promising therapeutic option.

Near normalization of metabolic and functional features of the central nervous system in type 1 diabetic patients with end-stage renal disease after kidney-pancreas transplantation.

OBJECTIVE: The pathogenesis of brain disorders in type 1 diabetes (T1D) is multifactorial and involves the adverse effects of chronic hyperglycemia and of recurrent hypoglycemia. Kidney-pancreas (KP), but not kidney alone (KD), transplantation is associated with sustained normoglycemia, improvement in quality of life, and reduction of morbidity/mortality in diabetic patients with end-stage renal disease (ESRD). RESEARCH DESIGN AND METHODS: The aim of our study was to evaluate with magnetic resonance imaging and nuclear magnetic resonance spectroscopy ((1)H MRS) the cerebral morphology and metabolism of 15 ESRD plus T1D patients, 23 patients with ESRD plus T1D after KD (n = 9) and KP (n = 14) transplantation, and 8 age-matched control subjects. RESULTS: Magnetic resonance imaging showed a higher prevalence of cerebrovascular disease in ESRD plus T1D patients (53% [95% CI 36-69]) compared with healthy subjects (25% [3-6], P = 0.04). Brain (1)H MRS showed lower levels of N-acetyl aspartate (NAA)-to-choline ratio in ESRD plus T1D, KD, and KP patients compared with control subjects (control subjects vs. all, P < 0.05) and of NAA-to-creatine ratio in ESRD plus T1D compared with KP and control subjects (ESRD plus T1D vs. control and KP subjects, P ≤ 0.01). The evaluation of the most common scores of psychological and neuropsychological function showed a generally better intellectual profile in control and KP subjects compared with ESRD plus T1D and KD patients. CONCLUSIONS: Diabetes and ESRD are associated with a precocious form of brain impairment, chronic cerebrovascular disease, and cognitive decline. In KP-transplanted patients, most of these features appeared to be near normalized after a 5-year follow-up period of sustained normoglycemia.

High incidence of severe cyclosporine neurotoxicity in children affected by haemoglobinopaties undergoing myeloablative haematopoietic stem cell transplantation: early diagnosis and prompt intervention ameliorates neurological outcome.

BACKGROUND: Neurotoxicity is a recognized complication of cyclosporine A (CSA) treatment. The incidence of severe CSA-related neurological complications following hematopoietic stem cell transplantation (HSCT) is 4-11%. METHODS: We describe 6 cases of CSA related neurotoxicity out of 67 matched related HSCT performed in paediatric Middle East patients affected by haemoglobinopaties (5 beta thalassemia major, 1 sickle cell disease-SCD). Conditioning regimen consisted of iv busulphan, cyclophosphamide and graft-versus-host-disease (GvHD) prophylaxis with CSA, methylprednisolone, methotrexate and ATG. RESULTS: All 6 patients presented prodromes such as arterial hypertension, headache, visual disturbances and vomiting, one to two days before overt CSA neurotoxicity. CSA neurotoxicity consisted of generalized seizures, signs of endocranial hypertension and visual disturbances at a median day of onset of 11 days after HSCT (range +1 to +40). Brain magnetic resonance imaging (MRI) performed in all subjects showed reversible leukoencephalopathy predominantly in the posterior regions of the brain (PRES) in 5/6 patients. EEG performed in 5/6 patients was always abnormal. Neurotoxicity was not explainable by high CSA blood levels, as all patients had CSA in the therapeutic range with a median of 178 ng/ml (range 69-250). CSA was promptly stopped and switched to tacrolimus with disappearance of clinical and radiological findings. All patients are symptoms-free at a median follow up of 882 days (range 60-1065). CONCLUSIONS: Our experience suggests that paediatric patients with haemoglobinopaties have a high incidence of CSA related neurological events with no correlation between serum CSA levels and neurotoxicity. Prognosis is good following CSA removal. Specific prodromes such as arterial hypertension, headache or visual disturbances occurring in the early post-transplant period should be carefully evaluated with electrophysiological and MRI-based imaging in order to intervene promptly and avoid irreversible sequels.

High-dose cytarabine plus high-dose methotrexate versus high-dose methotrexate alone in patients with primary CNS lymphoma: a randomised phase 2 trial.

BACKGROUND: Chemotherapy with high-dose methotrexate is the conventional approach to treat primary CNS lymphomas, but superiority of polychemotherapy compared with high-dose methotrexate alone is unproven. We assessed the effect of adding high-dose cytarabine to methotrexate in patients with newly diagnosed primary CNS lymphoma. METHODS: This open, randomised, phase 2 trial was undertaken in 24 centres in six countries. 79 patients with non-Hodgkin lymphoma exclusively localised into the CNS, cranial nerves, or eyes, aged 18-75 years, and with Eastern Cooperative Oncology Group performance status of 3 or lower and measurable disease were centrally randomly assigned by computer to receive four courses of either methotrexate 3.5 g/m(2) on day 1 (n=40) or methotrexate 3.5 g/m(2) on day 1 plus cytarabine 2 g/m(2) twice a day on days 2-3 (n=39). Both regimens were administered every 3 weeks and were followed by whole-brain irradiation. The primary endpoint was complete remission rate after chemotherapy. Analysis was by intention to treat. This study is registered with ClinicalTrials.gov, number NCT00210314. FINDINGS: All randomly assigned participants were analysed. After chemotherapy, seven patients given methotrexate and 18 given methotrexate plus cytarabine achieved a complete remission, with a complete remission rate of 18% (95% CI 6-30) and 46% (31-61), respectively, (p=0.006). Nine patients receiving methotrexate and nine receiving methotrexate plus cytarabine achieved a partial response, with an overall response rate of 40% (25-55) and 69% (55-83), respectively, (p=0.009). Grade 3-4 haematological toxicity was more common in the methotrexate plus cytarabine group than in the methotrexate group (36 [92%] vs six [15%]). Four patients died of toxic effects (three vs one). INTERPRETATION: In patients aged 75 years and younger with primary CNS lymphoma, the addition of high-dose cytarabine to high-dose methotrexate provides improved outcome with acceptable toxicity compared with high-dose methotrexate alone. FUNDING: Swiss Cancer League.

Detection of cerebral metastases on magnetic resonance imaging: intraindividual comparison of gadobutrol with gadopentetate dimeglumine.

BACKGROUND: Contrast-enhanced magnetic resonance (MR) imaging with gadolinium-based contrast agents is widely used for the detection of cerebral metastases with standard contrast agents. Newer developments in MR contrast agents have led to a higher relaxivity and/or concentration for these agents. PURPOSE: To assess the effectiveness of a standard dose of 1.0 M gadobutrol compared with a standard dose of gadopentetate dimeglumine for the MR detection of brain metastases. MATERIAL AND METHODS: 27 patients with at least one cerebral metastasis were examined twice with contrast-enhanced MR imaging, using gadobutrol at 0.1 ml/kg and gadopentetate dimeglumine at 0.2 ml/kg (i.e., identical gadolinium dosage of 0.1 mmol/kg bodyweight). The interval between examinations was 18 hours, and the order of injection was fully randomized. Images were acquired using a three-dimensional (3D) fast gradient echo sequence, and evaluated in blinded fashion by two experienced neuroradiologists in consensus in terms of the total number of lesions detected at each examination in each patient and qualitatively in terms of the lesion conspicuity observed. RESULTS: A total of 67 lesions were detected after gadobutrol compared with 65 lesions detected after gadopentetate dimeglumine. In two patients, a lesion was seen only after gadobutrol. Qualitative comparison of images revealed improved lesion conspicuity after gadobutrol in 10/27 cases compared with 0/27 cases after gadopentetate dimeglumine, and equivalent conspicuity in 17/27 cases (P=0.002, gadobutrol vs. gadopentetate dimeglumine). CONCLUSION: At equal gadolinium dosage, gadobutrol appears to offer significant advantages over gadopentetate dimeglumine for the visualization of brain metastases, with particular benefit for improving the conspicuity of detected lesions.

High relaxivity contrast agents in MR angiography of the carotid arteries.

Magnetic Resonance Angiography (MRA) is one of the most practical diagnostic imaging modalities in the field of neurovascular imaging where risks associated with catheter angiography are high. Evaluation of the extracranial supraortic vessels, and in particular the carotid arteries, is the major field of application for MRA. Before the development of rapid contrast-enhanced (CE) acquisition sequences, the major limitations of MRA pertaining to the carotid arteries was the limited volume of study when 3D time-of-flight (TOF) images were acquired, and the saturation effects together with low spatial resolution and movement artifacts when 2D TOF images were acquired. Although technical improvements helped overcome some of these limitations, MRA was still not considered a valid diagnostic alternative to DSA for the evaluation of carotid artery stenosis until the advent of CE acquisitions. Most published studies on CE-MRA of the carotid arteries have been performed with standard gadolinium-based chelates which have similar r1 relaxivity values. Newer gadolinium chelates such as gadobenate dimeglumine (Multihance, Gd-BOPTA, Bracco) have higher intravascular r1 relaxivity than other agents such as Gd-DTPA. This leads to higher vascular peak enhancement of longer duration which has proven beneficial for improving vascular contrast. CE-MRA is today considered a highly suitable replacement for conventional MRA techniques and DSA for the evaluation of extracranial carotid artery disease. Compared with unenhanced MRA sequences, CE-MRA permits complete and reliable evaluation of the internal carotid artery from the bifurcation to the intracranial segment. Moreover, the technique offers better overall accuracy for the depiction of tight stenosis and more confident diagnosis of real carotid occlusion versus subocclusive stenosis.