MRI is a non-invasive imaging modality with a high contrast resolution useful in diagnosing intracranial artery dissections. However, conventional MRI techniques, including time-of-flight MR angiography or basi-parallel anatomical scanning provide only limited information because they focus on imaging findings rather than the vessel walls. A newly devised MRI technique, high-resolution vessel wall imaging (HRVWI), enables direct visualization of vessel wall and therefore more accurate diagnosis. With increasing use of HRVWI, physicians need to understand the clinical indications, MR sequences for assessment, optimization of acquisition parameters, and limitations in the interpretation of images. For precise interpretation of images, physicians should be aware of the pathological condition of intracranial artery dissection and its radiological findings. In this review, we provide an overview and principles of MRI assessment used for intracranial artery dissection paying special attention to its pathological findings and radiological presentations on HRVWI.

Alexander disease (ALXDRD) is a primary astrocyte disease caused by glial fibrillary acidic protein (GFAP) gene mutation. ALXDRD had been clinically regarded as a cerebral white matter disease that affects only children for about 50 years since the initial report in 1949; however, in the early part of the 21st century, case reports of adult-onset ALXDRD with medulla and spinal cord lesions increased. Basic research on therapies to reduce abnormal GFAP accumulation, such as drug-repositioning and antisense oligonucleotide suppression, has recently been published. The accumulation of clinical data to advance understanding of natural history is essential for clinical trials expected in the future. In this review, I classified ALXDRD into two subtypes: early-onset and late-onset, and detail the clinical symptoms, imaging findings, and genetic characteristics as well as the epidemiology and historical changes in the clinical classification described in the literature. The diagnostic criteria based on Japanese ALXDRD patients that are useful in daily clinical practice are also mentioned.

Over the course of the new coronavirus infectious disease (coronavirus disease 2019; COVID-19) pandemic, our social situation has been changing dramatically, in addition to the substantial efforts made for the early and appropriate management of COVID-19 and preventing this infection spreading. Recently, neurological symptoms associated with COVID-19 have been shown to be not uncommon, with headaches receiving attention as one of the main neurological symptoms. The frequency of headaches associated with COVID-19 ranged from 5.6% to 70.3%, based on 21 clinical studies and 8 meta-analyses. However, headaches were observed in 11.1% to 81.0% of non-COVID-19 individuals, including healthcare workers caring for COVID-19 patients. Although detailed descriptions of headaches were rarely provided in the literature obtained, in this article, I wil discuss the frequency and characteristics of headaches, and the pathophysiology of headaches as it relateds to COVID-19.

An 82-year-old man with advanced lung cancer who had declined aggressive therapy was transferred to our hospital due to sudden-onset consciousness disturbance, global aphasia, and right hemiplegia. An electrocardiogram showed atrial fibrillation, and brain MRI and MRA revealed acute ischemic lesions of the left hemisphere and occlusion of the left internal carotid artery (ICA), respectively. We diagnosed acute ischemic stroke due to left ICA occlusion and performed endovascular thrombectomy, which resulted in complete recanalization of the left ICA after retrieval of the culprit embolus. Pathological examination of the retrieved thrombus revealed the presence of tumor tissue, as well as fibrin or red blood cells. Treatment was continued after admission, but the patient died of respiratory failure on day 40 of hospitalization. Autopsy revealed invasion of the tumor in the pulmonary vein, but not in the wall of the left atrium where thrombi were present. However, pathological examination of these thrombi in the left atrium revealed tumor tissue, along with fibrin or red blood cells. These findings suggest that the wall of the left atrium, in which lung cancer had not invaded, may be an incubator of a mixed embolus containing tumor tissue and thrombi in a case of cerebral embolism associated with both lung cancer and atrial fibrillation.

We report a 77-year-old man who presented with numbness and weakness of the feet bilaterally, that had progressed over 13 years. He was diagnosed with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) on the basis of nerve conduction studies and a sural nerve biopsy; however, he was inadequately treated and his weakness had progressed. At 76 years of age, he developed spasticity in the legs as well as bladder and rectal incontinences. Gd-enhanced MRI revealed severe compression of the cervical cord by massively enlarged nerve roots. A cervical laminectomy was performed to decompress the cervical cord. A fascicular biopsy of the C5 dorsal root showed a prominent lymphocyte infiltration and edema. Repeated methylprednisolone pulse therapy and IVIg ameliorated the weakness. We concluded that the main cause of nerve root hypertrophy in this patient was active inflammation.

A 23-year-old man admitted to our hospital with headache and dysarthria. Head MRI showed multiple acute cerebral infarctions in the right posterior circulation. Atlantoaxial dislocation, atlas dysplasia and thrombotic occlusion of right vertebral artery (VA), and blood flow disruption due to cervical rotation was observed. The axial dental process bordered to the right VA, and repeated contact stimulation by cervical rotation may cause intimal damage resulting in thrombotic occlusion. In this case, various systemic malformations such as atrial septal defect, atlas posterior arch hypoplasia, bovine left common carotid bifurcation malformation, double inferior vena cava and horseshoe kidney may have been congenital syndromes. Atlantoaxial dislocation may be an important and under-recognized cause of stroke in young adults.

We report a case of severe sensory-motor axonal neuropathy on the lower extremities associated with diabetic ketoacidosis (DKA). A sixteen-year-old boy developed coma and admitted to our hospital. We diagnosed him with DKA based on remarkable hyperglycemia, severe acidosis with hyperketonemia. Intensive glycemic control with insulin was immediately started. He had complications of heart failure, rhabdomyolysis, and renal failure, which required intensive care including mechanical ventilation and hemodialysis. When recovered from the critical condition, he noticed severe weakness, numbness, and pain on the lower limbs, and urinary retention. On nerve conduction studies, both motor and sensory action potentials were absent. Serum anti-ganglioside antibodies were negative. Albuminocytologic dissociation was evident in the cerebrospinal fluid. MRI study revealed marked gadolinium enhancement of the cauda equina. After high-dose intravenous immunoglobulin treatment, he was relieved from leg pain, but the leg weakness and bladder bowel dysfunction did not show immediate improvement. It took approximately six months until he became able to stand and walk using ankle orthosis. Acute neuropathy is a rare complication of diabetes mellitus. Painful neuropathy is known to emerge in association with diabetic treatment, but it seldom causes severe motor disturbance. On the other hand, motor-dominant polyneuropathy has been reported to occur acutely along the treatment of DKA and hyperosmolar hyperglycemia syndrome (HHS). Present case and previous cases with DKA and HHS suggest that rapid correction of glucose level is one of the underlying factors of acute neuropathy related with diabetic treatment.

A 72-year-old man on hemodialysis for 7 years with end-stage renal disease was admitted to our institution due to an acute headache. Physical examination revealed normal signs except for noise on the back of his neck. His head CT and brain MRI showed no abnormal findings, while his MRA demonstrated abnormal signals in the left transverse to sigmoid sinus (T-S) suggesting a left dural arteriovenous fistula. After admission, his headache persisted and left orbital numbness also occurred. His digital subtraction angiography performed on the 5th day after admission showed no vascular malformation of either the T-S or cavernous sinus (CS). However, it showed occlusion of the left brachiocephalic vein (BCV) and the origin of the left internal jugular vein (IJV) resulting in intracranial venous reflux. These findings indicated the possibility that his acute headache was caused by intracranial venous reflux and increase of intracranial pressure resulting from the occlusion of the BCV ipsilateral to a dialysis shunt. Percutaneous transluminal angioplasty (PTA) for occlusion of the left BCV was performed on the 9th day and successful dilation of the lesion with a residual stenotic ratio less than 30 percent was obtained. After the angioplasty, venous reflux to the intracranial vein was markedly reduced and his headache and orbital numbness disappeared. One day after the procedure, MRA demonstrated the disappearance of the abnormal signals of the left T-S. Twelve months after discharge, he felt discomfort in the left of his face and the re-occlusion of the left VCV was demonstrated by angiography, therefore he received re-PTA. We recommend that physicians consider occlusion of the BCV ipsilateral to a dialysis shunt and intracranial venous reflux as a cause of acute headache in patients on hemodialysis.

A 17-year-old woman presented with transient consciousness impairment attack and convulsion after bathing and prolonged standing since age 12. EEG showed WHAM ( wake, high amplitude, anterior, male) type of phantom spikes that usually carry the high risk of epilepsy at age 13. At age 17, EEG wise generalized spike and wave complex was recorded once, and head-up tilt test was positive. She was carefully observed without antiepileptic drugs since convulsive syncope due to neurally mediated syncope was most likely. During the follow-up period, she had eventually unprovoked generalized tonic-clonic seizures (convulsive seizure) twice and thus she was started with antiepileptic drug with success. Although both convulsive syncope and convulsive seizure differ in nature and effects on quality of life, in this patient, the latter occurred later and both occurs together. It is important to distinguish them by means of the degree of convulsion and EEG finding.

We report a 62-year-old female with rheumatoid meningitis. She presented with mental disorder, loss of consciousness, generalized seizures, and cognitive impairment. Brain MRI demonstrated high intensity lesions and abnormal enhancement along the left frontal and parietal sulci. Her serum and cerebrospinal fluid were positive for anti-cyclic citrullinated peptides (CCP) antibody, and the antibody index of cerebrospinal fluid anti-CCP antibody increased, which led us to suspect rheumatoid meningitis. Her symptoms improved immediately by methylpredonisolone pulse therapy and anti-CCP antibody turned negative in cerebrospinal fluid. However, she revealed arthritis with the reduction of betamethasone and was diagnosed as rheumatoid arthritis. We suggest that the elevation of antibody index of cerebrospinal fluid anti-CCP antibody is useful in the diagnosis of rheumatoid meningitis preceding neurological symptoms without arthritis, and anti-CCP antibody in cerebrospinal fluid may be helpful as the evaluation of the treatment.