Brain damage in commercial breath-hold divers.

BACKGROUND: Acute decompression illness (DCI) involving the brain (Cerebral DCI) is one of the most serious forms of diving-related injuries which may leave residual brain damage. Cerebral DCI occurs in compressed air and in breath-hold divers, likewise. We conducted this study to investigate whether long-term breath-hold divers who may be exposed to repeated symptomatic and asymptomatic brain injuries, show brain damage on magnetic resonance imaging (MRI). SUBJECTS AND METHODS: Our study subjects were 12 commercial breath-hold divers (Ama) with long histories of diving work in a district of Japan. We obtained information on their diving practices and the presence or absence of medical problems, especially DCI events. All participants were examined with MRI to determine the prevalence of brain lesions. RESULTS: Out of 12 Ama divers (mean age: 54.9±5.1 years), four had histories of cerebral DCI events, and 11 divers demonstrated ischemic lesions of the brain on MRI studies. The lesions were situated in the cortical and/or subcortical area (9 cases), white matters (4 cases), the basal ganglia (4 cases), and the thalamus (1 case). Subdural fluid collections were seen in 2 cases. CONCLUSION: These results suggest that commercial breath-hold divers are at a risk of clinical or subclinical brain injury which may affect the long-term neuropsychological health of divers.

Anatomical evaluation of the dural sinuses in the region of the torcular herophili using three dimensional CT venography.

RATIONALE AND OBJECTIVES: The torcular herophili, or "confluence of the sinuses," shows various configurations with other venous sinuses, as revealed by angiography. The aims of this study were to evaluate anatomic variations of this confluence and to assess their clinical relevance using three-dimensional (3D) computed tomographic (CT) venography. MATERIALS AND METHODS: The torcular herophili and its relevant venous sinuses were analyzed using 3D CT venography in 120 adults, consisting of 76 patients who were proven to have aneurysms and 44 patients who were proven to have no vascular malformations or aneurysms after the examinations. Three-dimensional CT venography was performed following the arterial phase of 3D CT angiography without any additional injection of contrast material. Three-dimensional volume-rendered venous images were reconstructed on a workstation and reviewed. RESULTS: The superior sagittal sinus (SSS) drained into the transverse sinus (TS) in four patterns: the SSS reached the centrally located confluence, where it divided into the bilateral TS (20.0%); the SSS was prematurely duplicated into the right and left limbs and drained into the same side TS (26.7%); the SSS drained exclusively into the right TS (44.2%); or the SSS drained exclusively into the left TS (9.2%). The draining pattern of the straight sinus was also classified into four types. The right TS was larger than the left TS. The right TS were higher compared to the left TS. Persistent occipital sinuses were recognized in 57.5% of the subjects. Finally, persistent falcial sinuses were seen in 2.5% of the subjects. A septum in the SSS and complicated venous channels in the confluence were each seen in only one case. CONCLUSION: Three-dimensional CT venography is useful as a noninvasive method to evaluate the confluence and its relevant dural sinuses and can provide useful information for surgical intervention.

[Case report of traumatic hemorrhage from the anterior choroidal artery].

Traumatic hemorrhage from the anterior choroidal artery is very rare. A 74-year-old male was admitted to our hospital immediately after a traffic accident. CT on admission showed right intracerebral hematomas in the posterior limb of the internal capsule and the upper part of the right cerebral peduncle. Neurological examination revealed that the patient had left hemiparesis and transient mute, pseudobulbar sign and peduncular hallucination. The absence of hypertensive asymptomatic microbleeds in other basal ganglia supported the verdict of traumatic injury of the anterior choroidal artery. The tear mechanism of the anterior choroidal artery might have been caused by an impact to the parietal region directed toward the tentorium.

[Isolated trigeminal sensory neuropathy due to pontine infarction of the root entry zone--report of two cases].

Secondary trigeminal neuralgia and isolated trigeminal neuropathy due to ischemic lesion of the pons are very rare. We report 2 patients with pontine infarct transecting the central trigeminal pathways resulting in trigeminal neuropathy and/or neuralgia. Case 1: A 48-year-old female presented with lancinating pain and paresthesia and hypesthesia in the right V2 and V3 distributions. Magnetic resonance imaging (MRI) of the brain demonstrated a wedge-shaped infarct at the root entry zone (REZ) of the right trigeminal nerve in the pons. Case 2: A 66-year-old female presented with paresthesia and hypesthesia in the right V1, V2 and V3 distributions. MRI demonstrated a small wedge-shaped infarct at REZ. This infarction of the REZ may have led to produce the isolated trigeminal neuralgia and trigeminal neuropathy.

A randomized, double-blind study comparing the safety and efficacy of clopidogrel versus ticlopidine in Japanese patients with noncardioembolic cerebral infarction.

BACKGROUND: Patients treated with ticlopidine require careful hematologic monitoring. Clopidogrel may have greater tolerability. However, no direct comparison of these two drugs has been reported and evidence of improved safety with clopidogrel is not yet established in the Japanese population. A comparison of both agents was therefore conducted in Japanese stroke patients. METHODS: Patients with noncardioembolic cerebral infarction were randomized to clopidogrel 75 mg or ticlopidine 200 mg once daily for 52 weeks. The primary endpoint was safety; the major secondary endpoint was the incidence of vascular events. RESULTS: Clopidogrel was associated with significantly fewer safety events than ticlopidine (7.0 versus 15.1%; p < 0.001) and no significant difference in efficacy between the two treatments was seen [hazard ratio 0.977 (95% confidence interval: 0.488-1.957)]. CONCLUSIONS: In Japanese stroke patients, clopidogrel 75 mg is better tolerated than ticlopidine 200 mg once daily.

[Rapid disappearance of acute epidural hematoma by percutaneous aspiration of subperiosteal hematoma--case report].

We present the case of an 8-year-old boy who was injured in a bicycle accident and was admitted with a right frontal skull fracture, an acute epidural hematoma, a right frontal laceration, and a subperiosteal hematoma on admission. After the frontal cutaneous suture, the subperiosteal hematoma was aspirated by the percutaneous needle. Two hours later, a CT scan revealed that the epidural hematoma was disappeared. It is speculated that the subperiosteal and epidural hematoma communicated via the skull fracture thus necessitating the evacuation of the epidural hematoma by subperiosteal aspiration.

Effect of the Ca antagonist nilvadipine on stroke occurrence or recurrence and extension of asymptomatic cerebral infarction in hypertensive patients with or without history of stroke (PICA Study). 1. Design and results at enrollment.

BACKGROUND: We examined the effect of a Ca antagonist (nilvadipine) on the occurrence or recurrence of symptomatic stroke in hypertensive patients with MRI-defined asymptomatic cerebral infarction (ACI), periventricular hyperintensity (PVH), and deep and subcortical white matter hyperintensity (DSWMH), with or without a history of stroke, and evaluated the effect of long-term treatment on the lesions. METHODS: Patients with hypertension and incidental ACI were divided into those with (group B, 235 patients) or without (group A, 181 patients) a history of symptomatic stroke, and were given nilvadipine 4-8 mg/day for 3 years. Primary evaluation points were occurrence of symptomatic ischemic stroke and development or extension of asymptomatic ischemic lesions. RESULTS: Male sex, hyperuricemia, diabetes, maximum diameter of infarction and PVH severity were stronger risk factors for group B. Numbers of cerebral infarctions were 31 +/- 28 (group A) and 42 +/- 32 (group B) at enrollment (p < 0.001). Infarctions were larger and located more frequently on the internal capsule, putamen, thalamus and brainstem in group B. The severity of PVH and DSWMH paralleled the number of cerebral infarctions in both groups. CONCLUSION: The study design and status of asymptomatic ischemic brain lesions in hypertensive subjects at enrollment are presented.

[Conjugate deviation in ischemia of medial medullary oblongata--report of three cases].

Medial medullary infarct (MMI) is a rare type of brain stem infarction. Its clinical picture was characterized by contralateral hemiparesis, deep sensory disturbance, and ipsilateral hypoglossal paresis, but conjugate deviation or nystagmus is uncommon as initial symptom. Case 1: A 73-year-old man developed vomiting and vertigo. Examination revealed right conjugate deviation and horizontal nystagmus beating toward the left side, and numbness on his right upper limb,but no hypoglossal nerve palsy. Cranial MRI demonstrated an infarction in the left paramedian region of the upper medulla and thrombus of the left vertebral artery. Case 2: A 74-year-old man suffered from dizziness and nausea. He showed left conjugate deviation and right-beating horizontal nystagmus without Horner syndrome or hypoglossal nerve palsy. MRI disclosed an infarction in the right upper medial medulla. MRA revealed the right dissecting vertebral artery. Case 3: A 71-year-old man developed vertigo when watching at TV. He showed transient left conjugate deviation and transient motor paresis on the left upper limb. MRI showed the thickened wall of the right vertebral artery but no abnormal ischemic lesion. Digital subtraction angiograms revealed the dissecting right vertebral artery. All ischemic events limited to the upper third of the medulla were caused by the vertebral artery lesions, and prognosis was good. The unilateral MMI lesion in the nucleus prepositus hypoglossi and/or the medullary reticular formation caused contralesional shift of the eyes and ipsilesional nystagmus. The upper MMI will be characterized by a triad of contralateral hemiparesis, deep sensory disturbance and abnormal ocular motor findings.

CT angiography in the evaluation of intracranial occlusive disease with collateral circulation: comparison with MR angiography.

The purpose of this study is to determine whether three-dimensional computed tomography angiography (CTA) is superior to magnetic resonance angiography (MRA) in the evaluation of collateral circulation in patients with intracranial arterial occlusive disease. Conventional angiography was used as the standard reference. Collateral vessels were well visualized by CTA, but not by MRA, while conventional angiography revealed leptomeningeal collateral vessels that were filled in a retrograde fashion. CTA is superior to MRA for evaluating collateral vessels.

Curvilinear T1 hyperintense lesions representing cortical necrosis after cerebral infarction.

Curvilinear T1 hyperintense lesions in the cerebral cortex in patients with subacute infarction were investigated for: (1) the presence or absence of T2* hypointensity and (2) correlations with neuropathologic findings. Thirty-six consecutive patients with subacute to chronic embolic infarction, in whom curvilinear hyperintense lesions in the infarcted cortex were seen on T1-weighted images, underwent echo-planar gradient-echo (GRE-EPI) T2*-weighted imaging. GRE-EPI T2*-weighted imaging revealed no evidence of hemorrhage within the curvilinear T1 hyperintense lesions of the cerebral cortex in all of the patients. In 11 of the 36 patients, focal hypointense lesions were seen in the depth of infarcted gyri on GRE-EPI T2*-weighted images. In the remaining 25 patients, no T2* hypointensities were seen in the infarct zone. Pathological correlation was performed in a patient with middle cerebral artery infarction and curvilinear hyperintense lesions on postmortem T1-weighted images. In the autopsied brain, curvilinear T1 hyperintense lesions corresponded to necrosis of all the cortical layers on histological examination. These data suggest that curvilinear hyperintense lesions in the cerebral cortex on T1-weighted images during the subacute to chronic period of cerebral infarction may not represent hemorrhage.

[Delayed epidural bleeding caused by traumatic pseudoaneurysm of the middle meningeal artery: case report].

A 16-year-old man who presented with delayed bleeding of epidural hematoma is reported. Computed tomography (CT) on admission demonstrated a small amount of right epidural hematoma and a small fracture of the right lateral orbital wall. He was treated conservatively. Repeated CT scans and magnetic resonance (MR) imaging revealed no growth in the epidural hematoma, but demonstrated flow void sign at the medial side of the hematoma on MR images. After 8 days, CT scan presented the regrowth of the hematoma, so we planned the removal of hematoma. Epidural hematoma due to the rupture of a traumatic pseudoaneurysm of the middle meningeal artery is rare. Especially, since traumatic lesions were diagnosed by CT, it was unusual to be able to diagnose the pseudoaneurysm of middle meningeal artery preoperatively. The cases of epidural hematoma treated conservatively should be followed up by MR imaging and MR angiography using the fat suppression technique.

[Rapid improvement of callosal edema by thiamine administration in Marchiafava-Bignami disease: a case report].

Marchiafava-Bignami disease (MBD) associated with chronic alcoholism is a fatal disorder characterized by demyelination of the corpus callosum. A 62-year-old Japanese man, a heavy drinker for his last over 10 years, was admitted to our hospital because of acute onset of speech disturbance. The first MR images showed abnormal signal intensity of the corpus callosum, which was a typical finding of MBD, but no signal abnormality on diffusion-weighted images. At three days after large doses of thiamine administration, MR studies revealed the disappearance of callosal high signal intensity. His symptom gradually improved, the pathogenesis and therapy of MBD were discussed.

Practical visualization of internal structure of white matter for image interpretation: staining a spin-echo T2-weighted image with three echo-planar diffusion-weighted images.

BACKGROUND AND PURPOSE: To our knowledge, no method satisfactory for clinical use has been developed to visualize white matter fiber tracts with diffusion-weighted MR imaging. The purpose of this study was to determine whether superposition of a spin-echo T2-weighted image and a color-coded image derived from three orthogonal diffusion-weighted images could show fiber tract architecture of the brain with an image quality appropriate for accurate reading with a computer monitor. METHODS: MR images from 50 consecutive cases were reviewed. Three diffusion-weighted images per section were acquired with three orthogonal motion-probing gradients. These images were registered to a corresponding spin-echo T2-weighted image. A color-coded image was synthesized from three diffusion-weighted images by assigning red, green, or blue to each diffusion-weighted image and then adding a spin-echo T2-weighted image with a weighting factor. The ability of the superposed image to delineate the white matter pathways was evaluated on the basis of the known anatomy of these pathways and qualitatively compared with that of the spin-echo T2-weighted image. RESULTS: The main white matter fiber pathways, in particular the superior longitudinal fascicle, corpus callosum, tapetum, optic radiation, and internal capsule, were more clearly and easily identified on the superposed image than on the spin-echo T2-weighted image. The time required to produce the superposed image was approximately 40 minutes. CONCLUSION: Superposition of a spin-echo T2-weighted image and a color-coded image created from three orthogonal diffusion-weighted images showed structures of the brain that were not clearly visible on the spin-echo T2-weighted image alone. Such superposition presents images that are easy to interpret correctly.

Detection of deoxygenation-related signal change in acute ischemic stroke patients by T2*-weighted magnetic resonance imaging.

BACKGROUND AND PURPOSE: Acute decreases in the MR T2*-weighted signal have been reported in experimental models of middle cerebral artery occlusion. This has been attributed to blood deoxygenation in association with an increased brain oxygen extraction fraction. The aim of this study was to detect this signal by susceptibility-weighted MR imaging in acute ischemic stroke patients. METHODS: Dynamic susceptibility contrast-enhanced MR (DSC-MR) imaging was performed within 4 hours of stroke onset in 6 patients with unilateral cerebral artery occlusion (middle cerebral artery, n=5; internal carotid artery, n=1). Cerebral blood volume was estimated on a pixel-by-pixel basis. DSC-MR images taken before arrival of the contrast medium were examined visually to identify hypointense areas. Bilateral regions of interest were set in the middle cerebral artery territory for comparison of the mean signal intensity. A semilogarithmic plot of signal intensity versus cerebral blood volume for every pixel in the region of interest was also analyzed. RESULTS: The side on which the hypointense area was seen was significantly correlated with the side of arterial occlusion. The mean signal intensity was significantly smaller on the affected side than on the contralateral side. The semilogarithmic plot of signal intensity versus cerebral blood volume indicated greater deoxyhemoglobin concentrations for the ipsilateral than for the contralateral region of interest. CONCLUSIONS: DSC-MR images allow detection of hypointensity in the affected cerebral hemisphere in acute ischemic stroke patients. Such hypointensity may indicate increased oxygen extraction fraction (misery perfusion) and may provide information valuable to patient care.