Marinos Kontzialis

High-Resolution 3D Magnetic Resonance Imaging of the Sixth Cranial Nerve: Anatomic and Pathologic Considerations by Segment.

Background: Weakness of the sixth cranial nerve is the most common cause of an ocular motor cranial nerve palsy. It is often difficult to identify a corresponding abnormality on neuroimaging to correlate with the clinical examination. Evidence Acquisition: High-resolution 3D skull base magnetic resonance imaging (MRI) allows for visualization of the sixth nerve along much of its course and may increase sensitivity for abnormalities in regions that previously were challenging to evaluate. In this review, the authors share their experience with high-resolution imaging of the sixth nerve. Results: For each segment, anatomic features visible on high-resolution imaging are described along with relevant pathologic entities. Conclusions: We present a segmental approach to high-resolution 3D MRI for evaluation of the sixth nerve from the nuclear to the orbital segment.

Spinal Nerve Root Enhancement on MRI Scans in Children: A Review.

Spinal nerve root enhancement in pediatric patients is generally nonspecific, and clinical and laboratory correlation is essential. Nerve root enhancement indicates lack of integrity of the blood‐nerve barrier. In this review, we will present a range of pediatric conditions that can present with spinal nerve root enhancement including inflammatory, infectious, hereditary, and neoplastic causes. Familiarity with the various pathologic entities associated with spinal nerve root enhancement is important for a concise differential diagnosis in the appropriate clinical setting. This will avoid unnecessary additional investigations.

Lesions in the Splenium of the Corpus Callosum on MRI in Children: A Review

A wide variety of conditions may involve the splenium of the corpus callosum on magnetic resonance imaging in children. A single cause may present with different patterns of splenial involvement, and multiple diseases may have similar imaging findings. Keeping this limitation in mind, the goal of this text is to assist in the diagnostic process of pediatric neurological diseases that are characterized by prominent involvement of the splenium of the corpus callosum on imaging. The various pathologies will be reviewed and categorized based on etiology, reversibility, and pattern of additional or associated findings. Transient splenial lesions in children are an uncommon radiologic finding of unknown etiology in a long list of conditions that may present with altered consciousness, and it usually carries a favorable prognosis. The discussion continues with the presentation of diseases inflicting irreversible damage on the splenium. Familiarity with the various causes implicated in splenial injury may assist in the formulation of differential diagnosis in the appropriate clinical setting using an easily recognizable imaging finding.

Teaching NeuroImages: Dyke-Davidoff-Masson in Sturge-Weber syndrome.

A 13-year-old boy with long-standing seizures presented with a port wine stain involving the left V1 trigeminal distribution, right hemiparesis, and left-sided glaucoma. MRI showed typical manifestations of Sturge-Weber syndrome (SWS) with cerebral atrophy and extensive pial angiomatosis1 (figure). Images also demonstrated findings of Dyke-Davidoff-Masson syndrome (DDMS) with compensatory calvarial expansion as a consequence of long-standing cerebral hemiatrophy.2 DDMS usually results from early insults to the developing brain. Symptoms reflect the underlying injury and include seizures, mental retardation, hemiparesis, and facial asymmetry. Seizure management in SWS is challenging and may include medical therapy or surgery in refractory cases.

Acute Brain Imaging in Children: Can MRI Replace CT as a Screening Tool?

To determine if axial T2‐weighted imaging can serve as screening tool for pediatric brain imaging.

Evaluation: Imaging Studies

The malignant or benign nature of a salivary gland (SG) tumor can be predicted with reasonably high accuracy by imaging. There is some overlap between the imaging findings of benign and malignant tumors, particularly for low-grade malignancies, and tissue diagnosis remains necessary for definitive diagnosis. Magnetic resonance imaging is the modality of choice for the evaluation of salivary neoplasms, as it allows for delineation of local infiltration, perineural spread and intracranial extension. This review will focus on the advanced imaging techniques that help to characterize SG tumors. A brief overview of the conventional imaging features of SG neoplasms is necessary before a discussion of the advanced imaging methods.

Susceptibility-weighted imaging in Todd paralysis

A 10-year-old boy presented with left hemiplegia and facial droop after prolonged seizure activity overnight. MRI showed hypoperfusion involving the right cerebral hemisphere. Susceptibility-weighted imaging (SWI) demonstrated prominence of ipsilateral draining veins, indicating increased deoxyhemoglobin content within the hypoperfused territory (figure).1 There was no acute infarct. Weakness improved over several hours and the patient was discharged after returning to baseline. While the pathophysiology of Todd paralysis remains elusive, prior reports have documented reversible hypoperfusion.2 SWI is a robust and relatively novel imaging technique that is highly sensitive to deoxyhemoglobin and can be an adjunct in the evaluation of perfusion abnormalities.

Hirayama disease: the importance of adequate flexion MRI for diagnosis

We read with great interest the recent correspondence by Cortese et al. [1], who described the importance of an early diagnosis of Hirayama disease (HD) in a patient who underwent conservative therapy. Herein, we stress the critical role of adequate flexion during dynamic MRI in the diagnosis of HD based on our recent experience. HD is a benign self-limiting disease that causes distal upper limb weakness and atrophy, which progresses over 2–4 years, followed by spontaneous arrest usually within 5 years. HD is thought to occur secondary to spinal cord compression by the posterior dural sac during neck flexion leading to ischemic damage to the anterior horns. The dynamic anterior shift of the dural sac is considered indicative of early progressive disease [2]. Imaging findings on neutral position MRI that should alert the physician include loss of normal cervical spine lordosis, loss of attachment between the posterior dural sac and subjacent lamina, lower cervical cord atrophy, and spinal cord T2 hyperintensity without evidence of extrinsic cord compression [3]. Flexion MRI is the appropriate next diagnostic step in suspected cases. An otherwise healthy 20-year-old male presented with a 2-year history of progressive right hand weakness and right upper extremity atrophy below the elbow. On clinical examination, there was no evidence of fasciculations, spasticity, or sensory deficits, and the atrophic changes spared the brachioradialis muscle. Needle electromyography showed chronic neurogenic changes in the form of fastfiring high-amplitude motor units. HD was suspected, and MRI of the cervical spine with flexion was ordered, which showed abnormal cord signal and segmental volume loss at C5–C6 (Fig. 1a). However, inadequate flexion with a tucked chin failed to demonstrate the expected anterior displacement of the posterior dural sac on the initial scan (Fig. 1b). Given the high clinical suspicion, MRI of the cervical spine was repeated in 3 months, when adequate flexion reproduced unequivocal imaging findings (Fig. 1c). Axial T2-weighted images in neutral position and flexion demonstrated abnormal cord signal, cord deformity and loss of attachment of the dural sac from the subjacent lamina (Fig. 2). HD is a slow progressive disease that can have good prognosis if detected and treated at an early stage and this case highlights the importance of adequate flexion MRI in & Marinos Kontzialis mkontzi1@jhmi.edu; marinoskon@gmail.com

Rheumatoid Pachymeningitis: A Rare Complication of Rheumatoid Arthritis

Rheumatoid pachymeningitis is a rare complication of rheumatoid arthritis (RA) and is a diagnosis of exclusion1,2. A 57-year-old male from El Salvador with a history of longstanding seropositive, nonerosive RA and interstitial lung disease, who was noncompliant with medical treatment, presented with severe occipital headache for about 8 months. The headache was associated with photophobia, phonophobia, and nausea, and was exacerbated by bending, laying supine, …

Teaching NeuroImages: Distinct brain microhemorrhage pattern in critical illness associated with respiratory failure

A 51-year-old man with dementia presented with altered mental status and unremarkable initial brain CT and MRI. Hospitalization was complicated by aspiration pneumonia, hypoxia, and acute respiratory distress syndrome requiring intubation. He improved with antibiotics, but 1 week later developed seizures. MRI revealed new multiple microhemorrhages involving the subcortical white matter, internal capsules, and corpus callosum, sparing the deep white matter and deep gray nuclei (figure). This distinctive pattern is seen in critically ill patients with respiratory failure1 and resembles high altitude exposure.2 It is important to distinguish this from other causes of microhemorrhages including hypertension, diffuse axonal injury, and amyloid angiopathy.