[Repetitive rhythmic spikes in epileptic children]

Repetitive rhythmic spikes (RRSs') sometimes appear periodically for 0.2-2.0 seconds at localized in epileptic children. We selected 11 patients (male 6, female 5) with RRSs for this study. Ages were 3-15 years (average 10.7 years). We counted the number of spikes which were recorded on the scalp EEG. The duration of RRSs and the differences of amplitude between large and small spikes on monopolar montages were examined. We also studied the appearance of spikes under different recording conditions; waking and sleep stages, photic stimulation and hyperventilation. Furthermore, we made two dimensional joint-dot plotting for the interval between repetitive spikes. RRSs were classified into two groups. In the first group, joint-dots of RRSs were locally observed between 0.2-0.8 sec. In the second, they were disseminated between 0.2-2.0 sec. In two groups, spikes were mainly observed in the sleep EEG (stage 1). The average number of spikes in the first group was 18.7/min, and that in the second was 25.7/min. The average difference of the amplitude between large and small spikes was 103 microV in the first group, and 88 microV in the second group. The average duration of spikes was 54.2 msec in the first group and 62.4 msec in the second group. From these results, it was assumed that some of spikes in the first group occurred in the surface of the cortex and that some of spikes in the second group were projected from the deep region in the cortex.

Spontaneous abdominal aortic dissection: case report and review

An abdominal aortic dissection was incidentally imaged by contrast infusion computed tomography (CT) in a patient with an abdominal liposarcoma. Previously reported cases of spontaneous abdominal aortic dissection with radiographs are reviewed.

Fogging effect and MR imaging: a case report of pontine infarction

We used serial MR imaging to examine a pontine infarct in an aged man. The fogging effect was observed on the images obtained 12 days after ictus. Knowledge of the fogging effect is important for a correct interpretation of MR imaging.

[MR imaging of basilar artery aneurysms]

Eight patients with basilar artery aneurysms (five fusiform, two saccular and one giant aneurysm) were studied by MRI at 1.5 tesla. Dilated lumen of basilar artery was detected in seven of eight patients on T2-weighted axial images. Deformity of pons was demonstrated in six of eight patients on T1-weighted midsagittal images. A fusiform aneurysm, 5 mm in diameter, could not be diagnosed by MRI. It was therefore concluded that MR imaging is relatively useful for diagnosing basilar artery aneurysms.

Asymptomatic Bochdalek hernia diagnosed by magnetic resonance imaging

An asymptomatic mass at the base of the left lung was examined by computed tomography (CT) and magnetic resonance (MR) imaging. Coronal and sagittal T1-weighted MR images provided a definitive diagnosis of Bochdalek hernia.

MR imaging of wallerian degeneration in the human brain stem after ictus

Magnetic resonance (MR) imaging of wallerian degeneration in the brain stem was studied in 30 hemiplegic patients within 12 months of ictus. As early as 25 days after the ictus, decreased signal intensities on proton-density(PD)-weighted images were observed in the brain stem ipsilaterally. This hypointensity gradually approached an isointense stage during 70-80 days after the ictus, abnormal intensities were not detected in any pulse sequence. We termed this phenomenon "Fogging effect of wallerian degeneration". In later stages, at least 81 days after the ictus, increased signal intensities on T2-weighted images, with or without decreased signal intensities on T1-weighted images, were observed in the brain stem, ipsilaterally. Finally, at least six months after the ictus, mild shrinkage of the ipsilateral brain stem was newly detected on the T1-weighted images. MR imaging has proven to be a sensitive diagnostic modality for evaluating wallerian degeneration in the brain stem.

[Intracranial lipoma; MR imaging]

Reported here are five patients with intracranial lipoma. Three of these had pericallosal lipoma. One patient had a lipoma in the quadrigeminal cistern. The remaining one had a lipoma in the interpeduncular cistern. All of these tumors were clearly demonstrated and were homogeneously hyperintense on T1-weighted MR images. One patient with a pericallosal lipoma had also partial agenesis of the corpus callosum. However, all patients had no symptoms relating these tumors. It was concluded that MR imaging is useful for diagnosing intracranial lipomas and associating anomalies.

CT of malignant mesenchymoma of the esophagus

Malignant mesenchymoma rarely originates from the gastrointestinal tract. Here we describe a case of an esophageal origin in a 50-year-old man. Computed tomography contributed to the diagnosis by having shown unique ossifications in the tumor.

[MR imaging of acute hemorrhagic brain infarction]

Six patients with acute hemorrhagic brain infarct were imaged using spin-echo (SE) pulse sequences on a 1.5 Tesla MR scanner. Including two patients with repeated MR imaging, a total of eight examinations, all performed within 15 days after stroke, were analyzed retrospectively. Four patients revealed massive hemorrhages in the basal ganglia or cerebellum and three cases demonstrated multiple linear hemorrhages in the cerebral cortex. On T1-weighted images, hemorrhages were either mildly or definitely hyperintense relative to gray matter, while varied from mildly hypointense to hyperintense on T2-weighted images. T1-weighted images were superior to T2-weighted images in detection of hemorrhage. CT failed to detect hemorrhages in two of five cases: indicative of MR superiority to CT in the diagnosis of acute hemorrhagic infarcts.

[MRI of middle cerebral artery occlusion]

Magnetic resonance imagings (MRIs) of ten patients with angiographically proved middle cerebral artery (MCA) occlusion were retrospectively reviewed. Eight of the ten patients had cerebral infarcts, one had an intraventricular hemorrhage, and the remaining one had no significant abnormalities. All patients were examined by the 1.5 Tesla SIGNA (GE), using spin-echo pulse sequences. In all patients, occluded MCA could be detected by MRI. All occluded arteries showed absence of flow void and were demonstrated as iso- or hyperintense structures relative to gray matter on T1-weighted images, iso- or hypointense on T2-weighted images. In eight of the ten patients, absence of flow void in the sylvian fissure was observed on T2-weighted images. Thus, MRI was proved to be a pertinent diagnostic modality for evaluating MCA occlusions.

[MRI of internal carotid occlusion and high-grade carotid stenosis]

Magnetic resonance imaging (MRI) of twelve patients with angiographically proved internal carotid artery (ICA) occlusions and a patient with high-grade ICA stenosis was retrospectively reviewed. In one of the occluded ICA cases, the bilateral ICAs were involved. All patients were examined by a 1.5 Tesla system, using spin-echo pulse sequences. Both absence of normal flow void and decreased caliber of the cavernous portion of the ICA were detected in all patients. In ten of the thirteen occluded ICAs, flow void was completely absent. Most of the occluded arteries were isointense relative to gray matter on T1-weighted images, and were mildly hypointense on T2-weighted images. "Partial flow void" was observed in four cases, including the high-grade stenosis patient. So-called "border zone infarcts" were detected in seven patients (eight hemispheres). In three of the thirteen cases, however, cerebral infarcts relating to the ICA occlusions or high-grade stenosis were not observed. Since detection of abnormal ICA before cerebral infarct has occurred is extremely significant, we want to stress that abnormal ICA must be routinely searched for in the routine review of MRI of the head.

MR imaging of intracranial vertebral artery occlusion

Magnetic resonance (MR) images of nine patients with intracranial vertebral artery occlusion (five proved, four presumed) have been reviewed. In two of nine, both vertebral arteries were occluded and in five of the nine, the basilar artery was also blocked. All occluded arteries showed absence of flow void and were clearly demonstrated as mildly hypo- approximately mildly hyperintense structures to brainstem parenchyma on the T1-weighted images. In two of five patients with basilar artery occlusion, retrograde filling of the distal basilar artery was detected. Thus, MR imaging, in particular the T1-weighted image, is a pertinent diagnostic modality for evaluating intracranial vertebral artery occlusion. Angiography does not seem to be required for confirmation.

Case report--MR imaging of chronic persistent hepatic encephalopathy

The MR images of a patient with chronic persistent hepatic encephalopathy are described. Mild cortical atrophy and multiple symmetrical hyperintense lesions were observed on T2-weighted MR images. No such case has been previously described in the literature.

[Acute hypertensive intracranial hemorrhage: MR imaging at 1.5T]

Twelve patients with acute hypertensive intracranial hemorrhage underwent magnetic resonance (MR) imaging within 7 days after the ictus. T1-weighted (TR = 400 msec; TE = 20 msec) and T2-weighted (TR = 2000 msec; TE = 80 msec) images were obtained on a 1.5 Tesla MR system. Signal intensities of hematomas were carefully evaluated and were compared with white matter intensity. A 9-hour-old hematoma was mildly hypointense on T1-weighted images, and was mildly hyperintense on T2-weighted images, suggesting a reflection of the high water content. On T2-weighted images, thin peripheral hypointense rim, probably due to deoxyhemoglobin, was also observed. Both of 15-hour-old hematoma and 21-hour-old hematoma had peripheral hypointensity on T2-weighted images. Both of 39-hour-old hematoma and 43-hour-old hematoma had central hyper-intensity on T1-weighted images and iso-to-mild central hypointensity on T2-weighted images, suggesting a reflection of decreased water content. A 3-day-old hematoma had thin peripheral iso-to-mild hyperintense rim on T1-weighted images, presumably due to intracellular methomoglobin. A 5-day-old hematoma had thin peripheral hyperintense rim on T2-weighted images, probably due to free methemoglobin. A 7-day-old hematoma was hyperintense on T1-weighted images and was mildly hypointense to hyperintense on T2-weighted images, presumably due to mixed intracellular methemoglobin and free methemoglobin.

[A variation of May-Thurner syndrome: a case report]

A 48-year-old man admitted with the complaint of a swollen left leg. Abdominal computed tomography demonstrated a tortuous left common iliac artery and a collapsed left common iliac vein. Contrast left iliac venogram revealed complete occlusion of the left common iliac vein. Abdominal aortography showed a tortuous left common iliac artery, which was thought to be compressing the left common iliac vein.

[Prophylactic embolization for unruptured aneurysm of the splenic artery; a case report]

A 67-year-old woman with liver cirrhosis underwent computed tomography (CT). The CT scan incidentally disclosed a large aneurysm of the splenic artery. Then, embolization therapy was performed using steel coils. No complications occurred. Usefulness of prophylactic embolization for unruptured aneurysm of the splenic artery was reported.

[MR imaging of cerebellar infarct]

Twenty-six patients with cerebellar infarct were studied with MR imaging at 1.5 T. Thirty-one infarctions were observed. Both T1- and T2-weighted images were useful for diagnosing cerebellar infarct. Large cerebellar infarcts were most frequently observed at the PICA territory. Small cerebellar infarcts were located in the border-zone between the SCA and the PICA territories. It was concluded that MR imaging is very useful for diagnosing cerebellar infarct.

Arteriovenous malformation of the corpus callosum associated with persistent primitive trigeminal artery--case report

A 16-year-old girl with a large, ruptured arteriovenous malformation (AVM) of the corpus callosum was studied by computed tomography and angiography. The relatively large nidus of the AVM was located mainly in the anterior portion of the corpus callosum, and there was a smaller nidus in the splenium. She also had a persistent primitive left trigeminal artery (PTA). This is the first reported case of an AVM with extensive callosal involvement associated with a PTA. She underwent radiation therapy and remained asymptomatic for 2 years thereafter.

[Computed tomography of calcaneal fractures--comparison with conventional radiography]

Computed tomography (CT) and conventional radiography were compared in 52 calcaneal fractures. As for CT, direct coronal imagings were performed in all and direct axial imagings were added in 27 of them. Conventional radiography included lateral, axial, and Anthonsen (oblique) views. Overall CT detected 7 more of the incongruity of the posterior facet, 9 more of the bulging of the lateral wall, and 6 more of the fracture of the sustentaculum tali than conventional radiography. In addition the entrapment of the peroneal tendons between the calcaneal body and the fibular malleolus could be evaluated only with CT. These informations are indispensable for the proper treatment of the fractures and we conclude that CT is useful in evaluating calcaneal fractures.

[MR imaging of brainstem infarction]

Thirty-three patients with old brainstem infarct were studied with MR imaging at 1.5T. T1-weighted images were most useful for diagnosing brainstem infarct. Brainstem infarcts were most frequently observed at the central portion of the mid pons. All of the lesions of three patients with medullary infarct were right sided. Both of the lesions of two patients with midbrain infarct were relatively large. Brainstem infarcts frequently accompanied supratentorial lacunar infarcts and subcortical arteriosclerotic encephalopathy.

Wallerian degeneration of the corticospinal tract in the brain stem: MR imaging

Magnetic resonance imaging (MRI) of wallerian degeneration of the corticospinal tract in the brain stem was studied in 25 patients with chronic supratentorial vascular accidents. In the relatively early stages, at least three months after ictus, increased signal intensities in axial T2-weighted images--with or without decreased signal intensities in axial T1-weighted images--were observed in the brain stem ipsilaterally. In later stages, at least six months after ictus, shrinkage of the brain stem ipsilaterally--with or without decreased signal intensities--was clearly observed in axial T1-weighted images. MRI is therefore regarded a sensitive diagnostic modality for evaluating wallerian degeneration in the brain stem.

[Magnetic resonance imaging in lateral medullary (Wallenberg's) syndrome]

Eight patients with a clinical diagnosis of lateral medullary (Wallenberg's) syndrome were studied with magnetic resonance imaging (MRI) at 1.5 Tesla. On T1-weighted axial images, small hypointense lesion (infarct) was demonstrated in the region of lateral medulla in 6 patients. Ipsilateral hemiatrophy of the medulla was revealed in one patient. In the remaining one patient, a thrombosed vertebral artery was disclosed. It was therefore concluded that MRI is useful diagnostic modality for Wallenberg's syndrome.

Arteriovenous malformation of the pancreas associated with mesenteric varices: case report and review of the literature

A 53-year-old man with an arteriovenous malformation of the pancreas associated with extensive mesenteric varices, liver cirrhosis, and hepatocellular carcinoma with arterioportal shunting was diagnosed by angiography. This is the first report of such a case with portal hypertension.

Selective catheterization of the brachiocephalic arteries via the right brachial artery

Selective intra-arterial digital subtraction angiography of the brachiocephalic arteries using the right brachial artery approach was successfully performed for 169 of 173 patients, 33 of whom were outpatients. Catheterization was unsuccessful for four patients; two of them elderly hypertensive men with tortuous brachial arteries, and two of them middle-aged obese women for whom arterial puncture could not be performed. 4-F modified Simmons type catheters were used in this study. Selective catheterizations of both common carotid arteries were successfully performed in all but one patient, a woman whose aberrant right subclavian artery prevented bilateral common carotid arterial catheterizations. Selective catheterizations of the right vertebral and left subclavian arteries, though relatively difficult, were successfully performed in 84.2% and 93.9% of patients, respectively. The mean examination time for a four-vessel study was 24.3 min. No major complications were encountered. Thus, transbrachial selective catheterization of the brachiocephalic arteries proved to be safe, useful, and relatively easy to perform.