ABSTRACT Neurofibromatosis type 1 (NF1) is a common inherited tumor predisposition syndrome with multisystem involvement of the central and peripheral nervous systems, vasculature, skeleton, skin, and internal organs. Many clinically relevant manifestations are internal, age‐dependent, progressive, or initially asymptomatic, making imaging central to diagnosis, surveillance, and treatment. This review provides a radiology‐centered overview of the major imaging manifestations of NF1 and emphasizes pattern recognition, modality selection, and imaging features that should prompt closer follow‐up, functional imaging, or tissue diagnosis with a focus on the pediatric population. The review covers optic pathway and non‐optic gliomas, plexiform neurofibromas, malignant peripheral nerve sheath tumors, abdominal neoplasms, focal areas of signal intensity/unidentified bright objects (FASIs/UBOs), NF1‐associated vasculopathy, and musculoskeletal dysplasias. MRI is the primary modality for evaluating CNS tumors, FASIs/UBOs, plexiform neurofibromas, spinal and paraspinal disease, dural ectasia, and whole‐body tumor burden. Diffusion‐weighted imaging and Fluordesoxyglucose (FDG)‐PET/MRI provide complementary information when malignant transformation of a plexiform neurofibroma is suspected. CT, CTA, MRA, ultrasound, radiography, and catheter angiography remain important in selected settings, particularly for skeletal dysplasia, intracranial and systemic vasculopathy, renovascular hypertension, and preoperative planning. NF1 imaging requires an integrated multisystem approach rather than isolated organ‐based interpretation. Careful assessment of lesion morphology, anatomic distribution, interval change, and clinical context enables clinicians to distinguish typical benign manifestations from findings suggestive of progression, malignant transformation, or clinically relevant vascular and skeletal complications.
BACKGROUND AND PURPOSE:We investigated whether early transcranial Doppler (TCD) ultrasound asymmetry indices could serve as bedside predictors of hemorrhagic transformation (HT) and 90-day outcome after successful endovascular thrombectomy (EVT). METHODS:Patients with successful reperfusion (thrombolysis in cerebral infarction [TICI] ≥2b) after M1-segment EVT who underwent bilateral TCD within 8 h post-EVT were included. Ipsilateral-to-contralateral ratios for mean flow velocity (MFV) and pulsatility index (PI) were calculated for M1 (segment of the middle cerebral artery) and M2 (segment of the middle cerebral artery) segments. Multivariate logistic regression identified independent predictors of HT and poor 90-day outcome. RESULTS:Among seventy patients (mean age 69.9 ± 6.7 years; 58.5% male), TCD was performed 5.3 ± 1.6 h after EVT. HT occurred in 45 patients (64.2%). Independent predictors of HT were younger age (p = 0.012), higher baseline NIHSS (p = 0.025), lower M2 PI ratio (p < 0.0001), and higher M2 MFV ratio (p = 0.010). Parenchymatous hemorrhage was predicted only by lower M2 PI ratio (p < 0.001). Poor 90-day outcome occurred in 35.7% and was associated with older age (p = 0.027), atrial fibrillation (p = 0.002), lower M2 PI ratio (p = 0.004), and higher M1 MFV ratio (p = 0.043). An M2 PI ratio ≤0.79 was associated with poor 90-day outcome with 89% specificity and 80% sensitivity (area under the curve [AUC] 0.91). CONCLUSIONS:Early M2 PI ratio was associated with PH-type HT and poor 90-day outcome; however, given the small sample size, wide confidence intervals, and lack of external validation, these findings remain hypothesis-generating rather than ready-to-use prognostic tools. Larger studies are needed to confirm these preliminary observations.
BACKGROUND AND PURPOSE:Brain magnetic resonance imaging (MRI) is an essential component for outpatient neurological evaluation, though access to timely imaging at the point of care is not feasible for most outpatient neurology practices. Portable ultra-low-field MRI systems offer a potential solution, but studies describing their clinical performance in routine outpatient neurology practice remain limited. This study evaluated clinical concordance and patient experience of portable MRI (pMRI) compared to standard-of-care MRI (sMRI) in independent neurology practices. METHODS:In this prospective, multicenter study, adults presenting to outpatient neurology clinics and requiring clinically indicated brain MRI completed imaging with both pMRI (0.064 T) and sMRI (91% 3 T, 9% 1.5 T) in the neurology clinic. All examinations were independently reviewed by board-certified neuroradiologists in a blinded, randomized fashion without access to clinical history. The primary endpoint was patient-level concordance between modalities for the presence or absence of abnormal findings. Discordant cases underwent post hoc unblinded paired review with clinical history to assess clinical significance. Secondary endpoints included patient-reported experience, assessed using a structured questionnaire evaluating noise, comfort, claustrophobia, anxiety, and overall experience on 10-point Likert scales, as well as modality preference. RESULTS:Among 125 participants imaged for common outpatient indications, including headache (40%), cognitive impairment or dementia (16%), multiple sclerosis follow-up (16%), and tumor surveillance (16%), portable and sMRI demonstrated 92% concordance on blinded review. Following clinically informed post hoc review, concordance increased to 98%. pMRI was rated more favorably across all patient experience domains (p < 0.001), and participants preferred pMRI (61%) over sMRI (14%) by a 4:1 ratio. CONCLUSIONS:In outpatient neurology practices, pMRI images demonstrated high clinical concordance with sMRI for identifying the presence or absence of structural brain abnormalities and were strongly preferred by patients. These findings support the use of pMRI as a practical point-of-care imaging tool for neurology patients, enabling timely access to structural neuroimaging during the clinical encounter.
BACKGROUND AND PURPOSE:Zotarolimus-eluting stents (ZES) are increasingly used off-label for intracranial atherosclerotic disease (ICAD), yet foundational preclinical data evaluating procedural delivery and short-term vascular safety in cerebral anatomy is sparse. We evaluated the procedural feasibility and 30-day clinical safety of the Onyx Frontier ZES in a canine intracranial model. METHODS:In a prospective study, 12 healthy canines on dual antiplatelet therapy underwent basilar artery implantation of a 2.0 × 8.0 mm Onyx Frontier ZES. Vertebral artery tortuosity was angiographically graded as Type I (mild), II (moderate), or III (severe). Endpoints focused on procedural success and 30-day clinical safety, monitored via angiography, serial neurological examinations, and clinical pathology. RESULTS:Technical success was 100% (12/12) despite challenging anatomy (mean basilar artery diameter: 1.39 mm). Tortuosity distribution was 33.3% Type I, 58.3% Type II, and 8.3% Type III. Post-deployment angiographic narrowing consistent with transient vasospasm was observed in 7/12 animals, without flow limitation; with only one requiring intra-arterial verapamil for resolution. One instance (8.3%) of self-limiting contrast extravasation occurred at the distal basilar artery without long-term sequelae. At 30 days, there was 0% mortality and no procedure-related neurological adverse events. Serial clinical pathology panels demonstrated an absence of systemic organ toxicity or sustained systemic inflammation. CONCLUSION:Implantation of the Onyx Frontier ZES is highly feasible in sub-2 mm, tortuous intracranial vessels. The platform demonstrated an excellent 30-day clinical safety profile, providing essential procedural and early clinical data to support future integrated regulatory evaluations for ICAD.
BACKGROUND AND PURPOSE:Spinal muscular atrophy (SMA) leads to progressive lower motor neuron loss. While neurophysiological techniques such as CMAP and MUNIX indirectly estimate motor unit number, few imaging-based biomarkers exist. We aimed to assess whether MRI-derived facial nerve diameters distinguish adult SMA patients from controls and correlate with clinical status. METHODS:We conducted a cross-sectional study including 22 adult SMA patients (Types II/III) and 14 age and sex-matched healthy controls at a single center. All participants underwent 3T brain MRI with bFFE sequences. Diameters of facial nerves were measured bilaterally at their brainstem root entry zones. Clinical assessments included ambulation status, facial weakness, Hammersmith Functional Motor Scale Expanded (HFMSE), and Motor Function Measure (MFM-32). RESULTS:There were four patients with SMA Type II and 18 with type III. Median age was 31.5 years. Facial nerve diameters were significantly reduced in patients compared with controls (right: median 1.15 vs. 1.40 mm; left: 1.14 vs. 1.35 mm). Within patients, ambulant individuals showed larger facial diameters than non-ambulant ones. Patients with clinical facial weakness had markedly smaller diameters. Diameters correlated with MFM (ρ up to 0.65) and HFMSE (ρ up to 0.68), while the facial-to-trigeminal ratio correlated even more strongly (ρ up to 0.73). No associations were found with disease duration. CONCLUSIONS:In this exploratory study, facial nerve diameter and the facial-to-trigeminal ratio showed promising associations with motor function in adult SMA, including in patients without overt facial weakness. These easily measurable MRI parameters warrant further investigation as potential biomarkers of motor neuron involvement.
