Kanta Tanaka

MRI of the cervical nerve roots in the diagnosis of chronic inflammatory demyelinating polyradiculoneuropathy: a single-institution, retrospective case–control study

Objective To systematically evaluate the usefulness of assessing the cervical nerve roots by MRI for the diagnosis of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). Design Single-institution, retrospective case–control study. Setting A regional referral hospital. Participants We retrospectively enrolled 15 consecutive patients with CIDP who satisfied the European Federation of Neurological Societies/Peripheral Nerve Society (EFNS/PNS) typical and definite criteria and underwent cervical MRI. 30 control patients who had also undergone cervical MRI were included, matched with regard to sex, age and MRI system. The diagnoses of the control patients included cervical spondylosis (n=19), cervical spine trauma (n=2), infection (n=1), malignancies (n=4), demyelinating disorders (n=2) and neurodegenerative disorders (n=2). Measurement A radiologist determined the C5–C8 root diameters on the coronal short tau inversion recovery (STIR) images. Signal intensities of these roots were quantified as nerve-to-muscle contrast-to-noise ratios (CNRs), which were calculated using mean signal intensities of the roots and sternocleidomastoid muscle as well as SD of background noise. Statistical analyses were performed to determine the diagnostic accuracy of the diameters and nerve-to-muscle CNRs. Another radiologist reviewed MRI for ensuring reproducibility. Results The root diameters showed no significant differences between the patients with CIDP and control patients. The nerve-to-muscle CNRs were significantly higher in the patients with CIDP. We defined the sum of nerve-to-muscle CNRs of C5–C8 roots as the CNR score to serve as an index of overall signal intensity. The area under the receiver operating characteristic curve of CNR scores was 0.731. The reproducibility of the assessment procedure was satisfactory. Conclusions Our results suggest that assessment of the cervical nerve roots by MRI is useful for CIDP diagnosis when the signal intensities, rather than the diameters, are paid more attention on STIR images.

Normalization of sonographical multifocal nerve enlargements in a MADSAM patient following a good clinical response to intravenous immunoglobulin

Focal nerve enlargements at sites of conduction blocks can be visualized sonographically in patients with multifocal acquired demyelinating sensory and motor neuropathy (MADSAM). However, little is known about association between nerve morphological changes and treatment responses. Here we present a 73-year-old female MADSAM patient whose sonographical multifocal nerve enlargements normalized following a good treatment response. She was admitted to our department with progressive asymmetrical muscle weakness and sensory disturbances for 6 months. Ultrasonography revealed multifocal nerve enlargements at sites of electrophysiological demyelination. Intravenous immunoglobulin improved her symptoms and electrophysiological abnormalities. Six months later, ultrasonography revealed normalization of multifocal nerve enlargements. Contrary to our observations, one previous report described a MADSAM patient with persistent nerve enlargements at the sites of resolved conduction blocks. In this earlier patient, however, the time from onset to remission was approximately 30 months. Morphological changes of nerve enlargements in MADSAM may vary with treatment response.

A case of painful seizure accompanying ictal paresis and homonymous hemianopia due to post-stroke epilepsy

A 69-year-old female with an old infarct of the left parietotemporal lobe was admitted for the evaluation of suspected painful seizures accompanying ictal paresis. The painful seizure and ictal paresis involved her right extremities without convulsions, although intermittent tremulous movements were noted on the right upper extremity. She also showed right hemianopia during the seizure. Ictal scalp EEG demonstrated lateralized rhythmic sharply contoured delta activity intermingled with a large amount of spikes, sharp waves, and fast activity mainly on the posterior half of the left hemisphere. Ictal MRI showed restricted diffusion in the postcentral gyrus and dilatation of distal branches of the left middle cerebral artery (MCA). 99mTc-ECD SPECT revealed hyperperfusion on the left parietal cortex. Treatment with antiepileptic drugs successfully prevented seizure recurrence, then she was discharged home. On the follow-up SPECT after 1 month, the abnormal hyperperfusion disappeared. MRI demonstrated resolution of the restricted diffusion and the MCA dilatation. Taken together with the EEG abnormality and the transient abnormalities in SPECT and MRI, we concluded that her seizures were epileptic and that her painful seizures likely arise from the left primary somatosensory cortex. The mechanism of ictal paresis would be attributed to some disturbed functional architecture in the left primary motor cortex leading to loss of normal motor function through epileptic interference by ictal discharges. The same mechanism in the visual cortex could be assumed for her ictal hemianopia. Painful seizure and ictal paresis each is rarely encountered, even more so the combination thereof. These ictal manifestations might be difficult to differentiate from transient ischemic attack or postictal paresis, and thus EEG is essential to diagnose this treatable condition.

Incongruous, incomplete, homonymous hemianopia due to an infarction localized to the lateral geniculate body

A 45-year-old male was admitted with an acute-onset visual field defect. Goldmann perimetry revealed an incongruent, incomplete right homonymous hemianopia. The left eye showed a wedge-shaped, horizontal right hemianopia, whereas the right eye showed constriction of the right visual hemifield. MRI showed acute infarction localized to the left lateral geniculate body (LGB). LGB has a dual blood supply: from the anterior choroidal artery and from the lateral posterior choroidal artery (LPChA). The LPChA territory of LGB receives projection from the retinal area around the macula and horizontal meridian. Therefore, an LPChA territory infarction of LGB can cause a wedge-shaped, horizontal visual field defect. The visual field defect in our patient would be caused by an LPChA territory infarction of LGB. Our patient showed an incongruent homonymous hemianopia. LGB has six laminae, with the ipsilateral retinal fibers terminating in layers two, three, and five and the crossed fibers terminating in layers one, four, and six. The laminar structure provides the anatomical basis for the incongruous visual field defects in a case of partial lesion of LGB. Based on the present data, we believe that an ischemic lesion localized to LGB should be considered in patients presenting with incongruous, incomplete homonymous hemianopia.

Spontaneous cervical spinal epidural hematoma presenting with hemiplegia

A 78-year-old man presented to the emergency department at Tenri Hospital, for acute left limb weakness 3 h and 20 min after its onset. He had experienced severe neck pain 30 min before the development of limb weakness. On examination, left hemiplegia was noted without facial weakness (Fig. 1a,b). There was no ptosis or anisocoria. Sensation to pinpricks and light touch was intact. He had urinary retention. Computed tomography and magnetic resonance imaging (MRI) of the head showed no causative abnormality. MRI of the neck showed an epidural hematoma extending from vertebral levels C2 to C5 (Fig. 1c,d). Because the hemiplegia persisted, the patient underwent decompressive surgery 13 h after its onset (Fig. 1e,f). He recovered without any residual symptoms (Fig. 1g). Spontaneous spinal epidural hematoma is an important stroke mimic, because intravenous thrombolysis might worsen bleeding. Hemiparesis is a common presentation of cervical spontaneous spinal epidural hematoma according to a literature review. Neurologists should consider spontaneous spinal epidural hematoma in patients with acute hemiparesis not affecting the face, particularly in those with severe neck pain.