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In patients with supratentorial intracerebral haemorrhage (ICH), it is important to discriminate superficial (lobar) and deep (basal ganglia) location, since this has consequences for research and prognosis. Haemorrhages at these sites have different causes and different risk factors. We studied the interobserver variation between three radiologists in classifying fifty large haematomas on CT as deep or lobar. The kappa values were almost perfect, ranging from 0.88 to 0.96. We conclude that the assessment of CT by radiologist is a reliable method to discriminate between lobar versus deep origin even for large intracerebral haematomas.

Objectives: This study was performed to assess the extent of functional involvement of the affected hemisphere in Sturge Weber syndrome in comparison with the uninvolved hemisphere. To this end beta activity in the electroencephalogram (EEG) was measured, both before and after administration of diazepam intravenously (i.v.)., Methods: In 9 patients asymmetry in beta band activity was studied before and after diazepam administration. Several beta bands and asymmetry parameters were calculated. beta band asymmetries were compared with structural abnormalities (magnetic resonance imaging, MRI)., Results: Total beta activity was reduced in the involved hemisphere in all patients after diazepam administration. In 3 patients functional abnormalities were found in brain regions that were structurally intact., Conclusions: Decreased diazepam-enhanced beta activity in the EEG is a sensitive criterion of functional abnormality. In patients with subtle structural abnormalities diazepam-enhanced EEG may have added value in diagnosing functional involvement and in monitoring disease progression in patients.

Object: The purpose of this study was to compare computerized tomography (CT) angiography and digital subtraction (DS) angiography studies in patients with subarachnoid hemorrhage (SAH) to assess their vascular anatomy relevant to cerebral aneurysm surgery., Methods: From a prospective series of 100 patients with SAH, the authors selected 73 patients whose CT angiography studies were of adequate quality and in whom DS angiography of both carotid arteries had been performed. Eleven patients with no DS angiographic studies of the vertebrobasilar artery were only evaluated for the anterior half of the circle of Willis. Anterior communicating arteries (ACoAs), both precommunicating anterior cerebral arteries (A1 segments), both posterior communicating arteries (PCoAs), and both precommunicating posterior cerebral arteries (P1 segments) were assessed on CT angiography and DS angiography by two independent observers., Conclusions: Computerized tomography angiography compares well with DS angiography for visualizing normal-sized arteries, and is superior for visualizing ACoAs and hypoplastic A1 and P, segments. Important preoperative aspects such as dominant A1 segments and PCoAs are equally well seen using either modality. Neither method enabled the authors to visualize more than 50% of PCoAs. Use of CT angiography can provide the required preoperative anatomical information for aneurysm surgery in most patients with SAH.

Purpose: To compare movement of the normal medullary cone when the patient has changed from a supine to prone position with that in patients with known or suspected tethered spinal cord syndrome., Materials and Methods: Fifty-six individuals divided into three groups were examined with lumbar spine magnetic resonance (MR) imaging performed with the patient in the prone and supine positions. Group 1 consisted of 15 healthy volunteers and six patients with a herniated disk; group 2, 25 patients clinically suspected of having a tethered cord; and group 3, 10 patients who previously had undergone tethered cord surgery., Results: All group 1 subjects showed distinct and statistically significant medullary cone movement (range, 21%--41%); no patient in group 3 showed movement (Wilcoxon rank sum test, P <.001). In group 2, the 20 patients in whom a definite diagnosis of tethered cord syndrome was made on the basis of initial supine MR image findings showed no movement, whereas two of five patients with normal supine MR images had abnormal and decreased cone movement at prone imaging., Conclusion: Prone MR imaging has no additional value when the supine MR image has clearly shown the cause of tethering or in patients who have undergone tethered cord surgery, but it can provide additional information in patients clinically suspected of having a tethered cord and in whom supine MR imaging depicted no abnormalities.

Sometimes, the clinical presentation of a brain tumour mimics that of stroke or vice versa, as exemplified in the following three patients. In a 73-year-old patient the initial clinical picture was compatible with a brachial plexus lesion, as the weakness in his right hand appeared to have a traumatic, and not a central nervous system related, cause. When he experienced a focal seizure, the CT scan of the brain revealed a lesion in the motor cortex. This was presumed to be an infarction due to the lack of mass effect and the absence of contrast enhancement. Shortly afterwards the patient deteriorated and a follow-up scan revealed a large contrast-enhancing lesion. During surgery this proved to be a glioblastoma multiforme. A 76-year-old man was suffering from a progressive neurological deficit. An MRI scan of the brain revealed a contrast-enhancing lesion and a chest X-ray revealed an asymptomatic lung tumour; the diagnosis 'brain metastasis' was made. The surgeon removed the lung tumour, which proved to be a carcinoma. Later, when the patient was referred to the neurosurgeon for extirpation of the presumed brain metastasis, the MRI scan revealed that the lesion had decreased in size and no longer exhibited contrast enhancement. The metastasis proved to be an infarction. A 53-year-old man presented with sudden loss of consciousness due to a haemorrhage in the occipital lobe. An angiogram did not reveal a vascular malformation and during surgery no abnormal tissue was seen. The patient almost made a complete recovery. However, several months later he developed an elevated intracranial pressure due to a large occipital high-grade glioma, which had caused the original haemorrhage.

A retrospective analysis of the clinical presentations and neuroimaging characteristics of 33 patients with a primary central nervous system lymphoma (PCNL) who received cranial radiotherapy was performed to assess incidence of and risk factors for radiation-induced encephalopathy. CT and MRI scans were revised by a neurologist and a radiologist in conference. White matter abnormalities before and after radiotherapy on the last scan before recurrence were quantified according to a semi-quantitative scale. All available medical records were retrieved and reviewed with respect to demographic and tumor-related variables, treatment modalities, disease-free and overall survival and clinical symptoms and signs of encephalopathy. CT and MRI scans showed severe white matter lesions in 75% of 20 patients and in 86% of patients aged more than 60 years. Forty percent of patients presented with new clinical signs of cognitive impairment a median of 14.5 months after initial diagnosis (8.5 months after radiotherapy). The risk of white matter lesions appeared greater in patients aged >60 (RR 1.2, 95% CI = 0.8-2.0), in patients with prior white matter lesions (RR 1.3, 95% CI = 0.8-2.1) and in patients with multifocal cerebral lymphoma (RR 1.5, 95% CI = 1.0-2.1). In conclusion, the risk of white matter lesions and clinical symptoms and signs of encephalopathy is high in patients treated by radiotherapy for PCNL. The risk appears to be greatest in older patients, patients with multifocal tumor and in those with prior white matter lesions on CT or MRI.

Objective: MR angiography may be an appropriate tool to screen for unruptured intracranial aneurysms. Feasibility, test characteristics, and interobserver agreement in evaluation of MR angiograms were assessed by members of the MARS (Magnetic resonance Angiography in Relatives of patients with Subarachnoid hemorrhage) Study Group., Subjects and Methods: We screened 626 first-degree relatives of a consecutive series of 193 patients with subarachnoid hemorrhage examined at two institutions. We used MR imaging and MR angiography (three-dimensional time-of-flight imaging at both institutions and additional three-dimensional phase-contrast imaging at one institution). Three observers independently assessed the MR angiograms. Conventional angiography was performed in relatives with possible or definite aneurysms on MR angiography and was considered the standard of reference., Results: Thirty-three aneurysms were found in 25 (4%; 95% confidence interval [CI], 3-6%) of 626 relatives. Thirteen (8%) of 169 relatives who refused screening had MR-related reasons; an additional six persons could not be screened because of contraindications for MR imaging (pregnancy, n = 1; claustrophobia, n = 5). The positive predictive value of MR angiography was 100% (95% CI, 79-100%) for "definite" aneurysms and 58% (95% CI, 28-85%) for "possible" aneurysms. Sensitivity of MR angiography was estimated at 83% (95% CI, 65-94%) and specificity at 97% (95% CI, 94-98%). Interobserver agreement in the evaluation of MR angiograms was poor (kappa < .30), probably because different diagnostic strategies used by individual observers resulted in different use of the assessment category "possible aneurysm.", Conclusion: MR angiography is a feasible screening tool for detection of intracranial aneurysms. Positive predictive value, sensitivity, and specificity are acceptable when at least two neuroradiologists independently assess MR angiograms.

Object: The purpose of this study was to determine prospectively whether and to what extent computerized tomography (CT) angiography can serve as the sole imaging method for a preoperative workup in patients with ruptured intracranial aneurysms., Methods: During a 1-year period, all patients who presented to the authors' hospital with subarachnoid hemorrhage demonstrated by unenhanced CT scanning or lumbar puncture underwent CT angiography. Two radiologists evaluated the CT angiography source images and maximum intensity projection slabs and arrived at a consensus. They categorized the quality of the CT angiography as adequate or inadequate and classified aneurysms that were detected as definitely or possibly present. The parent artery of anterior communicating artery aneurysms was identified by asymmetrical anterior cerebral artery size and asymmetrical aneurysm location. The parent artery was indicated by the larger A1 segment in cases of asymmetrical A1 size. Only CT angiograms of adequate quality that revealed aneurysms classified as definitely present and with an unequivocal parent artery were presented to the neurosurgeons, who decided whether preoperative digital subtraction (DS) angiography should still be performed. Forty-nine of the 100 studied patients did not undergo surgery because of poor clinical condition, nonaneurysmal cause of the hemorrhage, or endovascular treatment of the ruptured aneurysm. Of the 51 patients who underwent surgery, radiologists required DS angiography in 17 patients; the imaging technique provided greater certainty in 13 instances. The neurosurgeons required DS angiography 11 times; this provided additional information in two instances. Twenty-three (45%) of the 51 patients were surgically treated successfully on the basis of CT angiography findings alone., Conclusions: Computerized tomography angiography can replace DS angiography as the preoperative neuroimaging technique in a substantial proportion of patients with ruptured intracranial aneurysms.

Background and Purpose: It is important to recognize a perimesencephalic pattern of hemorrhage in patients with subarachnoid hemorrhage (SAH), because in 95% of these patients the cause is nonaneurysmal and the prognosis is excellent. The purpose of this study was to investigate whether CT angiography can accurately exclude vertebrobasilar aneurysms in patients with perimesencephalic patterns of hemorrhage and therefore replace digital subtraction angiography (DSA) in this setting., Methods: In 40 patients with posterior fossa SAH as shown on unenhanced CT, 2 radiologists independently evaluated unenhanced CT for distinguishing between perimesencephalic and nonperimesencephalic pattern of hemorrhage and assessed CT angiography for detection of aneurysms. All patients subsequently underwent DSA or autopsy., Results: Observers agreed in 38 of 40 patients (95%) in differentiating perimesencephalic and nonperimesencephalic patterns of hemorrhage on unenhanced CT. On the CT angiograms, both observers detected a vertebrobasilar aneurysm in 16 patients and no aneurysm in 24 patients. These findings were confirmed by DSA or autopsy. No patients with a perimesencephalic pattern of hemorrhage were found to have an aneurysm on either CT angiography or DSA., Conclusions: Good recognition of a perimesencephalic pattern of hemorrhage is possible on unenhanced CT, and CT angiography accurately excludes and detects vertebrobasilar aneurysms. DSA can be withheld in patients with a perimesencephalic pattern of hemorrhage and negative CT angiography.

Rationale and Objectives: To evaluate the diagnostic relevance of ipsilateral atrophy of the collateral white matter in the parahippocampal gyrus (ACWMp) and temporal lobe gray/white matter demarcation loss (GWDL) on magnetic resonance imaging in patients with histologically confirmed hippocampal sclerosis. In the second part of this investigation, histologic specimens were analyzed to find an explanation for GWDL., Methods: Retrospective visual assessment of hippocampal signal intensity and size and of ACWMp and GWDL was performed using 4- to 5-mm coronal T2-weighted spin-echo magnetic resonance images of 80 patients with histologically proven hippocampal sclerosis and of 30 age-matched controls without epilepsy. Frequency of occurrence and likelihood ratios of ACWMp and GWDL were calculated and their contribution to the diagnosis of hippocampal sclerosis was assessed, particularly in patients with no or restricted hippocampal abnormalities (either high signal or smaller size) on magnetic resonance imaging. The second part of the study involved the morphologic histologic assessment of neocortical temporal lobe specimens of all patients. Myelin density was evaluated in specimens of a subgroup of six patients with hippocampal sclerosis and GWDL on MRI and six patients with hippocampal sclerosis without GWDL., Results: ACWMp was found in 68% and GWDL in 65% of patients with hippocampal sclerosis on magnetic resonance imaging. Both features had an infinite positive likelihood ratio. Sixty-two patients (77.5%) had concomitant hippocampal signal increase and smaller size. Eighteen patients (22.5%) had no or restricted hippocampal abnormalities on magnetic resonance imaging. When using ACWMp and GWDL as additional diagnostic parameters, 13 of these 18 patients were more unambiguously diagnosed as having hippocampal sclerosis. No significant morphologic differences were found between GWDL-positive and GWDL-negative specimens. A significantly lower average myelin stain was found in the white matter of the GWDL-positive group compared to the GWDL-negative group., Conclusions: ACWMp and GWDL can improve the visual diagnosis of hippocampal sclerosis, particularly in patients with no or restricted hippocampal abnormalities. These results suggest that loss of myelin may be the underlying cause of GWDL in association with hippocampal sclerosis.

A 6-year-old boy developed progressive motor weakness and areflexia. The clinical picture, combined with electrophysiological findings, indicated a diagnosis of Guillain-Barré syndrome (GBS). MRI on admission revealed spinal cord swelling and increased signal intensity within the cord. It is concluded that, since a degree of central nervous system involvement can occasionally be part of the spectrum of GBS, swelling of the spinal cord without contrast enhancement does not exclude a diagnosis of GBS.

Rationale and Objectives: Definition of optimal magnetic resonance (MR) scanning plane and conventional MR sequence for the detection of mesial temporal sclerosis (MTS)., Methods: Coronal and axial T2-weighted images and axial T2-weighted images parallel to the long axis of the hippocampus (APLAH) and coronal inversion recovery (IR) images were obtained in patients with medically intractable temporal lobe epilepsy in their phase 1 preoperative evaluation. Thirty-three consecutive MR scans were reviewed by a panel of three radiologists. Twenty-three patients had MR abnormalities consistent with MTS, and ten scans were normal. To assess the best single scanning technique, another group of three radiologists, who were masked to all patient data, individually assessed the different planes and sequences of the 33 studies presented separately in a random fashion. For each plane and sequence, the likelihood (L) ratio for the correct diagnosis was determined separately., Results: For all planes considered separately, a likelihood ratio of 4.4 was optimal for the coronal T2-weighted images. The likelihood ratio of APLAH T2 was 2.2; of axial T2, 3.9; of coronal IR, indefinite because of 100% specificity., Conclusions: For the assessment of MTS, coronal T2-weighted images were considered the best single scanning technique.

We studied whether magnetic resonance (MR) imaging of the brachial plexus is useful to distinguish multifocal motor neuropathy (MMN) from lower motor neuron disease (LMND) and whether abnormalities resemble those of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). We compared MR images of the brachial plexus of nine patients with MMN with scans from five patients with CIDP, eight patients with LMND, and 174 controls. In two patients with MMN, and in three patients with CIDP, the MR images showed an increased signal intensity on the T2-weighted images of the brachial plexus. Two other patients with MMN demonstrated a more focal, increased signal intensity on the T2-weighted images, occurring in one patient only in the axilla, and in the other patient in the axilla and in the ventral rami of the roots. MR images of the brachial plexus of eight patients with LMND were normal. The distribution of the MR imaging abnormalities corresponded with the distribution of symptoms of the patients: asymmetrical in MMN and symmetrical in CIDP. These findings demonstrate that MR imaging abnormalities of the brachial plexus in patients with MMN resemble those seen in CIDP and may be useful to distinguish MMN from LMND.

Osteochondroma of the mandibular condyle is extremely rare and may cause signs and symptoms like those seen in patients with temporomandibular joint dysfunction. Differentiation between osteochondroma and condylar hyperplasia is not possible on histologic grounds alone, but the radiographic and intraoperative findings together are usually sufficient to establish a definite diagnosis.

Two temporomandibular joints from one specimen were investigated using magnetic resonance imaging and cryosectioning. Magnetic resonance images, photography of the tissue block surface, and on-tape histologic sections were compared. The left joint was imaged and sectioned in a coronal plane, and the right joint in an angulated coronal plane parallel to the long axis of the condyle. The temporomandibular joint disc could be seen in coronal and angulated coronal scans. The posterior band was imaged in angulated coronal magnetic resonance scans throughout the temporomandibular joint both medically and laterally. In coronal scans only parts of the disc proper could be seen, depending on the level of imaging or sectioning. The densely plaited fibrous tissue of the intra-articular tissues could be seen in magnetic resonance imaging, primarily anterior to the condyle; this tissue corresponded to the low signal intensity in magnetic resonance imaging. Medical and lateral disc attachments as well as the temporomandibular joint capsule were imaged in some of the magnetic resonance scans in both the coronal and the angulated coronal scans. In diagnosing anteromedial, medial, and lateral disc displacements, angulated coronal temporomandibular joint scanning is preferred over coronal scanning.

Purpose: To determine the frequency of appearance of various MR signs in mesial temporal sclerosis, to determine the optimal scanning planes for their visualization, and to propose a histologic explanation for the diminished demarcation between gray and white matter in the temporal lobe, a frequent MR finding in patients with mesial temporal sclerosis., Methods: MR scans of 14 surgically treated patients with epilepsy and histologically proven mesial temporal sclerosis were assessed for the presence of six features: feature 1, high signal intensity in the hippocampus; 2, reduced hippocampal size; 3, ipsilateral atrophy of the hippocampal collateral white matter; 4, enlarged temporal horn; 5, reduced gray-white matter demarcation in the temporal lobe; and 6, decreased temporal lobe size., Results: Feature 1 was present in 14 patients and was best appreciated on the T2-weighted images in planes parallel to the long axes of the hippocampi. Feature 2, present in 12 patients, and feature 6, present in 9 patients, were optimally seen in the coronal planes and on the inversion-recovery sequences in particular. Feature 3, present in 12 patients, was optimally seen on the coronal T2-weighted images. Feature 4, seen in 11 patients, was equally well seen in all planes (transverse, coronal, and parallel to the long axes of the hippocampi). Feature 5, seen in 10 patients, was best appreciated on the T2-weighted images in the planes of the long axes of the hippocampi. Histologic investigation of the temporal lobe white matter in the 10 patients with feature 5 demonstrated on the MR scan showed abnormalities in 7 cases. Oligodendroglia cell clusters were found in 6, with concomitant corpora amylacea in 1 case and perivascular macrophages with pigment a sole finding in another case., Conclusion: Of the six features found in cases of mesial temporal sclerosis on MR, increased hippocampal signal intensity is the most consistent. A decreased gray-white matter demarcation in the temporal lobe parenchyma is also a frequent feature of this disease. A combination of multiple scanning planes results in an optimal demonstration of lesions.

Purpose: To determine whether the lumbosacral junction of the vertebral column can be identified with sonography in newborns and infants and thus serve as a method for counting the lumbar and sacral vertebral bodies., Methods: In 32 newborns and infants, the number of ossified vertebral bodies distal to the lumbosacral junction was counted with sonography and radiography., Results: Sonographic and radiographic findings agreed in 29 of 32 examinations (91%)., Conclusions: The lordotic transition at the lumbosacral junction can be identified with sonography in the majority of newborns and infants, allowing intraspinal structures to be related to a specific vertebral level.

Two temporomandibular joints originating from one specimen were investigated using magnetic resonance imaging and cryosectioning. Magnetic resonance images, photographs of the surface of the tissue block, and on-tape sections were compared. The left joint was imaged and sectioned in a sagittal plane, the right joint in a plane perpendicular to the long axis of the condyle. The densely plaited fibrous tissue of the disc proper correlated extremely well with the low signal intensity in magnetic resonance imaging. The transition between the densely plaited fibrous tissue and the looser tissue of the posterior attachment was located anterior to the thickest part of the intra-articular tissues in most sections of the specimen. The temporomandibular joint disc could be seen in angulated as well as in sagittal magnetic resonance scans. The posterior band was imaged best in angulated magnetic resonance scans throughout the temporomandibular joint.

The purpose of this study was to test the hypothesis that a high lactate signal and a low N-acetyl-aspartate/choline ratio in neonates with postasphyxial encephalopathy indicated a high chance of an adverse outcome in vivo when proton magnetic resonance spectroscopy was used. Twenty-one full-term asphyxiated neonates were examined at a mean postnatal age of 7.1 d. Five patients died, and five survivors had handicaps. Eleven of the 16 survivors (seven without handicaps and four with handicaps) had a second examination at 3 mo of age. After magnetic resonance imaging, spectra were obtained at 1.5 tesla. A 20-mm-thick slice was selected through the basal ganglia. After optimizing the B-0 field, we used a double spin-echo pulse sequence (90-180-180 degrees) with a time to repeat of 2000 ms and a time to echo of 272 ms. Two-dimensional spectroscopic imaging was performed by 32 x 32 phase encoding steps in two directions in a 225-mm field of view, resulting in 1-mL volumes, followed by computerized processing. Neuromotor development was examined at 6 wk, 3 mo, and every 3 mo thereafter. Lactate resonances were seen only in the five patients with grade 3 postasphyxial encephalopathy. Lactate was distributed diffusely (n = 4), or localized in areas of infarction (n = 1). N-acetyl-aspartate/choline ratios were significantly lower in the patients with an adverse outcome than in the survivors without handicaps, both neonatally (p < 0.005, Wilcoxon's rank sum test) and at 3 mo (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

This paper deals with the impact MRI may have on radiotherapy treatment planning of brain tumors. The authors analyzed differences in size and position of treatment fields as indicated by three observers (two radiotherapists and one neuroradiologist) using CT or MR based radiotherapy planning procedures for cerebral-gliomas. Large differences in field size and position were found in non CT contrast enhancing tumors, all low grade gliomas. Small differences were found in contrast enhancing lesions including the high grade gliomas. We conclude that implementation of MRI in radiotherapy treatment planning leads to a greater precision in treatment fields for non CT contrast enhancing lesions.

In this paper the effects of reducing the flip angle of the 90-degree observation pulse in inversion recovery imaging are described and analyzed. When incorporated in an IR sequence with a short inversion time (STIR), reduction to the 90-degree pulse allows a significant shortening of the repetition time without loss in contrast, although at the expense of some signal/noise. The generalized STIR sequence thus combines the previously reported advantages of a conventional STIR sequence--suppression of ghost artifacts from abdominal wall movement, suppression of chemical shift and boundary artifacts, additive effects of N(H), T1 and T2 on image contrast--with reduced power deposition and the advantages resulting from shorter repetition times, viz, single heart-beat triggering, increased number of signal averages for suppression of motion artifacts, acquisition of interleaved contiguous slices without cross-talk or considerable time savings when the number of required slices is limited. The proposed method is demonstrated and experimentally verified by imaging experiments on phantoms and human subjects. In principle the method is applicable to all cases where STIR imaging has been proven to be successful.

In craniomandibular disorders the diagnosis of internal derangements plays an important role. Findings from the history and the examination of active movements mostly lead to a working diagnosis. Additional orthopedic tests and radiological examination (e.g. arthrography) give more precise information. MRI (Magnetic Resonance Imaging) is a new technique with which the temporomandibular soft tissues can be imaged in a non-invasive way without the use of radiation. The position and configuration of the disc can be visualized both in the intercuspidal position and with various degrees of mouth opening.

Two patients with retroperitoneal cystic lymphangioma are reported with a review of the medical literature. In one, the patient was asymptomatic from the lesion but had a computed tomography (CT) and an ultrasound to evaluate the extent of disease with a known carcinoma of the colon. The second patient presented with an acute abdominal pain requiring surgical management. CT on this patient showed multiple cystlike cavities filled with fluid, in a retroperitoneal location. The preoperative diagnosis of retroperitoneal cystic lymphangioma was confirmed at surgery. Magnetic resonance (MR) performed on the second patient gave better delineation of craniocaudal extent and showed one of the cysts to have probable hemorrhage.

In a case of diffuse xanthogranulomatous pyelonephritis, computed tomography (CT) and magnetic resonance (MR) were used. The MR proved to be more precise in the preoperative evaluation of inflammatory extension to the spleen and into the abdominal wall. The CT was more accurate in excluding spread to the colon.

Computed tomography (CT) is considered a useful modality in the diagnosis of hip abnormalities in children. In this article a procedure is described, using low dose CT with thick slices and integration of different images, in which radiation exposure is in ranges equal to the conventional methods. This makes CT the method of choice for routine examination.