Endovascular treatment of PICA aneurysms.

Endovascular treatment of aneurysms of the posterior inferior cerebellar artery (PICA) avoids manipulation of the brainstem or lower cranial nerves and should therefore carry a lower risk of neurological morbidity than surgical clipping. We reviewed our experience of 23 patients with PICA aneurysms treated by endovascular occlusion with Guglielmi detachable coils and documented their long-term outcome on follow-up. We observed a 28 day procedure-related neurological morbidity of 13% (3/23 patients). One patient suffered permanent neurological complications. There were no procedure-related deaths. None of our patients suffered a re-bleed from their treated aneurysms. Our series shows endovascular treatment of ruptured PICA aneurysms to be safe and effective.

Magnetic resonance imaging in the diagnosis and management of choroid plexus carcinoma in children.

BACKGROUND: Choroid plexus carcinoma (CPC) is a rare tumour occurring in childhood. The MRI features are not well described. OBJECTIVE: To characterise the MRI features of CPC in children and to describe the role of MRI in post-surgical management. MATERIALS AND METHODS: The pre- and post-operative MRI examinations of five children with histologically proven CPC treated at this hospital were reviewed. RESULTS: The tumour was supratentorial in two patients and infratentorial in three patients. Pre-operative MRI showed heterogeneous enhancing tumours with irregular margins, parenchymal invasion and surrounding oedema. Cystic change within the tumour was present in all patients. Curvilinear signal voids were seen in two patients and punctate signal voids in one. All patients had hydrocephalus. In one patient a fourth-ventricular metastasis was present at diagnosis. In all cases, surgical resection was incomplete. Follow-up found long-term survival in one patient who had been treated with chemotherapy and further surgery. CONCLUSION: The MRI characteristics of CPC are nonspecific, but intraventricular location with tumour heterogeneity, parenchymal invasion and oedema may be useful features in diagnosis. MRI is valuable in the initial diagnosis, surgical planning and follow-up of children with these rare tumours.

Craniovertebral abnormalities in Type VI mucopolysaccharidosis (Maroteaux-Lamy syndrome).

INTRODUCTION: The craniovertebral abnormalities found in patients with Type VI mucopolysaccharidosis (Maroteaux-Lamy syndrome) are described, and the indications for and outcomes of surgery in this group are assessed. METHODS: The clinical histories and radiological findings in all patients with Type VI mucopolysaccharidosis treated at Royal Manchester Children's Hospital during the past 10 years were reviewed. RESULTS: The typical findings in patients with this disease are of canal stenosis at the level of the foramen magnum and upper cervical spine with or without cord compression. The stenosis is secondary to thickening of the posterior longitudinal ligament. Atlantoaxial instability is rare. Of nine patients under regular clinical review, four underwent decompressive surgery for cervical cord compression. Three of the four showed improvement in their neurological symptoms and signs postoperatively. Of the children reviewed, six had radiological evidence of cord compression, although only those with neurological signs or symptoms were treated surgically. DISCUSSION: Despite the often formidable anesthetic challenge, surgery is indicated in those patients who present with progressive neurological deficit due to cervical myelopathy. Surgery can be undertaken safely if the associated medical problems in these children are recognized and managed appropriately.

The Oxfordshire Community Stroke Project classification in the early hours of ischemic stroke and relation to infarct site and size on cranial computed tomography.

BACKGROUND AND PURPOSE: The Oxfordshire Community Stroke Project (OCSP) classification clinically subdivides cerebral infarction into total anterior circulation (TACS), partial anterior circulation (PACS), posterior circulation (POCS) and lacunar (LACS) syndromes. We compared the OCSP classification in patients presenting within 12 hours of onset of stroke with infarct site and size on computed tomography (CT) brain scan at 5 to 7 days. METHODS: OCSP classification was prospectively assigned by 1 of 3 observers in 43 patients presenting within 12 hours of stroke. CT brain scan was performed on admission to exclude primary intracerebral hemorrhage. Repeat CT brain scan at 5 to 7 days was used to classify recent visible infarction as total anterior circulation infarction (TACI), partial anterior circulation infarction (PACI), lacunar circulation infarction (LACI), or posterior circulation infarction (POCI). For each OCSP subtype, sensitivity and specificity were calculated by using CT classification as a standard. RESULTS: Median (range) interval from onset of stroke symptoms to OCSP classification was 5.0 (1.5, 11.75) hours. Thirty-seven patients had ischemic stroke, with recent visible infarction in 34 (92%). Sensitivity and specificity of each OCSP subtype was TACS (0.80, 0.82), PACS (0.56, 0.79), LACS (0.33, 0.88), and POCS (1.00, 0.97). Overall, 65% of OCSP subtypes assigned were correct when compared to CT classification. CONCLUSIONS: In this small study, we have shown that the OCSP classification within 12 hours of ischemic stroke onset compares with CT classification at 5 to 7 days. Larger studies are required to evaluate the validity of the OCSP classification in the early hours of ischemic stroke in guiding appropriate patient selection for acute stroke therapy and interventions.

Incidental findings on magnetic resonance imaging screening for cerebellopontine angle tumours.

The otolaryngologist who requests magnetic resonance imaging (MRI) scans to exclude cerebellopontine angle (CPA) tumours may discover incidental pathologies. We retrospectively reviewed the results of 644 consecutive MRI screening scans with the aim of identifying findings other than CPA tumours. Two hundred and eighty-nine (45 per cent) scans featured one or more anomalies or abnormalities, including CPA tumour (23, four per cent), vascular loop (30, five per cent), basilar artery ectasia (13, two per cent), multiple high signal areas (135,21 per cent), brain atrophy (52, eight per cent), sinus findings (56, nine per cent), middle ear/mastoid disease (34, five per cent), and a variety of other findings (39, six per cent) including clinically serious lesions (11, two per cent). The significance and management of these incidental findings is discussed. The majority were not clinically significant but the occasional presence of a serious incidental pathology should be borne in mind. Basilar artery ectasia and multiple high signal areas may be responsible for the symptoms investigated by MRI, and screening for cerebrovascular disease risk factors in such patients may be appropriate.

Calculation of pulsed NMR signal in I = 3/2 quadrupolar spin system.

The rf pulse response of I = 3/2 spin system experiencing first order quadrupolar splitting is studied using density matrix approach. A general expression is derived in terms of spin populations, quadrupole splitting and duration and amplitude of the rf pulse for calculating the NMR signal arising due to the centre line and satellite resonances for the situation where the impressed rf pulse excites the resonances selectively as well as non-selectively. The necessary 4 X 4 transformation matrix obtained analytically by diagonalyzing the Hamiltonian are used to get the expression for the centre line response. The satellite signals are obtained in the same way but by using the numerical values of the roots of the related quartics. The widths of the corresponding pi/2-pulses are calculated for different initial spin populations. The variations of this pulse-width and the corresponding signal amplitude as a function of satellite splitting are studied.

Magnetic resonance imaging of the hypothalamic-pituitary axis in the diagnosis of growth hormone deficiency.

In order to investigate the relationship between pituitary appearance and the diagnosis of growth hormone deficiency (GHD), we have assessed magnetic resonance imaging (MRI) scans and GH status during provocation tests in 110 patients (78 males; median age 9.8, range 0.1-20 yr), evaluated for possible GH disorders. On the basis of pituitary function tests, patients were divided into GH deficient (GH peak < 15 mIU/l [5.8 ng/ml]) (n = 82) or GH sufficient (GH peak > 15 mIU/l) (n = 28). The former were further divided into those with multiple hormone deficits (MPHD) (n = 19) or isolated GHD - severe IGHD (peak GH < 8 mIU/l [3.1 ng/ml]) or partial IGHD (8-15 mIU/l). The appearance of the hypothalamic-pituitary (H-P) axis was classified as: (1) normal, (2) isolated hypoplastic stalk (HPS), (3) isolated hypoplastic anterior lobe (HPAL) (PHT SDS < -2.0), (4) HPS + HPAL or (5) ectopic posterior lobe (EPL). The last two were considered severe abnormalities. PHT SDS (mean +/- SD -2.0 +/- 2.2) was correlated to log peak GH levels in the whole group (r = 0.45; p < 0.0001) and in the GHD group (r = 0.39; p < 0.0001). Sixty-five out of 82 in the GHD group had a H-P axis abnormality (45 severe abnormalities), while 13 out of the 28 patients in the GH sufficient group also had an abnormality (3 severe, but none with an EPL). All patients with MPHD had a MRI abnormality, most commonly an EPL (79%). Thus the presence of any MRI abnormality as a marker for GHD would generate a sensitivity of 79%, but a specificity of only 54%, indicating that this could not be used to confirm GHD. However, the presence of either an EPL or HPS + HPAL on MRI is highly specific (100% and 89% respectively) and predictive of GHD (positive predictive value 100% and 79% respectively), indicating that these abnormalities provide confirmation of the diagnosis. We recommend that if clinical, auxological and biochemical data indicate a diagnosis of GHD, then a MRI scan should be undertaken to define the pituitary anatomy and to help confirm the diagnosis.

Solitary exostosis of the thoracic spine. Early diagnosis and treatment.

STUDY DESIGN: A case report. OBJECTIVE: To highlight the importance of early diagnosis and treatment of vertebral exostosis. SUMMARY OF BACKGROUND DATA: Few cases of spinal cord compression caused by solitary thoracic exostoses have been reported. METHOD: A solitary exostosis in the midline of the neural arch of the fifth thoracic vertebra, causing compression of the spinal cord documented on both magnetic resonance and computed tomographic examinations, is reported in a 51-year-old woman who had normal findings in a neurologic examination. RESULTS: The exostosis was successfully excised. CONCLUSION: Accurate preoperative diagnosis of vertebral exostoses is possible using magnetic resonance and computed tomography. Early excision avoids the development of a permanent neurologic deficit.

Pain drawings in the assessment of nerve root compression: a comparative study with lumbar spine magnetic resonance imaging.

STUDY DESIGN: Prospective comparative study of pain drawings with findings on lumbar spine magnetic resonance imaging. OBJECTIVES: To assess the ability of the pain drawing to predict the presence of nerve root compression. SUMMARY OF BACKGROUND DATA: Most research work has concentrated on the ability of the pain drawing to act as a screening method for psychological distress with less work directed at the influence the anatomic abnormality has on the pain drawing. METHODS: One hundred thirty-four consecutive outpatients attending for lumbar magnetic resonance imaging in the investigation of back and leg pain completed pain drawings and psychological testing immediately before the examination. The pain drawing was analyzed by previously reported criteria, and the magnetic resonance imaging was assessed independently for the presence of nerve compression by three radiologists. Multivariate stepwise discriminant analysis was used to identify patients with nerve compression on the basis of their pain drawing. RESULTS: Nerve compression was predicted by numbness in the anterolateral aspect of the foot. There was considerable overlap in the appearances of the pain drawings between patients with and without nerve compression, and the pain drawing correctly classified only 58% of patients with nerve compression. CONCLUSIONS: The pain drawing is not a good predictor of nerve compression on magnetic resonance imaging in a group of patients investigated for back and leg pain. It should be interpreted with caution and in light of the full clinical picture.

Experiences with functional magnetic resonance imaging at 1 tesla.

Functional magnetic resonance imaging (fMRI) has been performed on a standard 1 T system using a pulse sequence developed to utilize blood oxygen level dependent (BOLD) contrast and an off-line analysis routine using correlation techniques. The sequence and the data analysis routine have been validated by reproducing the conventional hand movement paradigm studies reported by numerous other workers. Our work has then been extended to investigate cerebral foci for a tonic pain stimulus and the cortical representation of oesophageal stimulation. Both these studies relate to paradigms where the expected BOLD signal is significantly less than that encountered for motor or visual cortex paradigms. The results show good agreement with other modalities (positron emission tomography, magnetoencephalography and cortical evoked potentials). Performing fMRI at 1 T is slightly controversial. However, our successful study of demanding paradigms, using a standard clinical 1 T imaging system, has important implications for many other users operating at this field strength.

Measurement of vertebral rotation in adolescent idiopathic scoliosis using three-dimensional magnetic resonance imaging.

STUDY DESIGN: This report examines a technique for measurement of axial vertebral rotation using magnetic resonance imaging. OBJECTIVES: To assess the reproducibility of three-dimensional magnetic resonance imaging in the measurement of vertebral rotation at individual endplates in patients with adolescent idiopathic scoliosis. SUMMARY OF BACKGROUND DATA: Deformity in the sagittal and coronal planes in patients with adolescent idiopathic scoliosis can be readily assessed from plain radiographs, but the degree of deformity in the axial plane is more difficult to determine. Plain film techniques have inherent inaccuracies because of loss of definition of anatomic landmarks, and the use of computed tomography is limited by the high radiation dose associated. Magnetic resonance imaging provides a means of imaging scoliotic deformity that allows multiplanar reconstruction and that involves no use of ionizing radiation. METHODS: Ten patients with adolescent idiopathic scoliosis were imaged in a Siemens 1-Tesla impact scanner. Three-dimensional volume images of the apical five vertebrae were obtained in the axial plane and were postprocessed through multiplanar reconstruction. Sections through the superior and inferior endplates of each vertebra were selected in the sagittal and coronal planes, allowing axial reconstructions to be obtained in the plane of each endplate. Vertebral rotation was measured by identifying datum points on the inner surfaces and at the junction of the laminas and comparing the angle subtended by these points with a vertical drawn by the computer. Measurements were obtained from the single scanning sequence on two occasions by one observer and on one occasion by a second observer. Interobserver and intraobserver error was evaluated and correlation with readings obtained from plain films using Perdriolle's torsiometer method assessed. RESULTS: The interobserver variation had a mean of 3.02 degrees (range, 0-10 degrees) and a 95% confidence interval of [2.51 degrees, 3.53 degrees]. The intraobserver variation had a mean of 2.56 degrees (range, 0-7 degrees) and a 95% confidence interval of [1.83 degrees, 3.29 degrees]. The mean difference between measurements obtained from magnetic resonance imaging and plain film was 3.29 degrees (range, 0-12 degrees) with a 95% confidence interval of [1.43 degrees, 5.15 degrees]. CONCLUSIONS: The degree of vertebral rotation can be accurately and reproducibly assessed by three-dimensional magnetic resonance imaging. Measurements can be made through individual endplates that allow assessment of the relative amount of intervertebral and intravertebral deformity.

MRI of the brain and craniocervical junction in Morquio's disease.

We reviewed MRI of the brain and cervical spine in 11 patients with Morquio's disease. No abnormality was seen in the brain. The odontoid peg was abnormal in all patients, with varying degrees of cord compression due to an anterior soft tissue mass and indentation by the posterior arch of the atlas. The degree of cord compression was more marked than suggested by the symptoms and signs. We recommend MRI of the cervical spine in children with Morquio's disease before the development of neurological symptoms, to optimise the timing and type of surgical intervention.

MRI appearance of popliteal cysts in childhood.

Popliteal cysts are soft fluid-filled lesions of synovial origin which result from extrusion of joint fluid into the gastrocnemiosemimembranous bursa. They may occur in any age group, but 22-33 % occur in the first 15 years of life. In this age group they are rarely associated with intraarticular abnormalities and therefore rarely require treatment. This case report shows the magnetic resonance imaging (MRI) appearances of a popliteal cyst in two children.

MRI of lumbar spondylosis: a comparison of sagittal T2 weighted and three sequence examinations.

The aim of this study was to determine whether a single T2 weighted sagittal sequence could replace the conventional three sequence examination of the lumbar spine. The T2 weighted sagittal image of 79 lumbar spine MRI examinations were retrospectively reported by three radiologists. Features relating to degenerative disease were recorded and an assessment made of whether further sequences were likely to add information. On a separate occasion the T1 weighted and T2 weighted sagittal and T2 weighted axial sequences were reported blind in relation to the initial assessment. Areas of disagreement were resolved by consensus opinion. The T2 weighted sequence was compared with the three sequences, taking the three sequence examination as the standard. Disc protrusions were diagnosed from the T2 weighted sagittal images with a sensitivity of 38% and a specificity of 97%. 22 discs reported as a disc bulge on the T2 weighted sequence were re-classified as a disc protrusion on axial images because of their focal nature. Central canal stenosis was diagnosed on the T2 weighted sagittal sequence with a sensitivity of 60% and a specificity of 95%. After assessing the T2 weighted sequence, it was thought unlikely that further sequences would add extra information in 60% of cases (48/79). However, further information was obtained in 21% of these cases (10/48) when all the sequences were assessed. The extra information gained by using all three sequences was considered to be of greater benefit than the time saved by using a single T2 sagittal sequence. Other diagnoses where the additional sequences proved helpful are discussed.

The cortical topography of human swallowing musculature in health and disease.

Because no detailed information exists regarding the topographic representation of swallowing musculature on the human cerebral cortex in health or disease, we used transcranial magnetic stimulation to study the cortical topography of human oral, pharyngeal and esophageal musculature in 20 healthy individuals and the topography of pharyngeal musculature in two stroke patients, one with and one without dysphagia. Our results demonstrate that swallowing musculature is discretely and somatotopically represented on the motor and premotor cortex of both hemispheres but displays interhemispheric asymmetry, independent of handedness. Following stroke, dysphagia appeared to be associated with smaller pharyngeal representation on the intact hemisphere, which increases in size with recovery of swallowing.

Magnetic resonance imaging of the brain, neck and cervical spine in mild Hunter's syndrome (mucopolysaccharidoses type II).

Magnetic resonance imaging (MRI) of the brain, neck and cervical spine of five patients with the mild variant of Hunter's syndrome (iduronate sulphate sulphatase deficiency, mucopolysaccharidosis Type II, MPS II) are described and compared with the few available reports in the literature. The most prominent abnormalities in the brain include ventriculomegaly and brain atrophy, the presence of well defined cystic areas of decreased signal on T1- and increased signal on T2-weighted images, of the thalamus, basal ganglia and brain stem, and decreased signal on T1-weighted and increased signal changes on T2-weighted sections of the periventricular and subcortical white matter. A giant cisterna magna was present in four patients and a J-shaped sella in three. Thickening of the soft tissue posterior to the odontoid peg was present with associated canal stenosis in all cases resulting in compression of the cervical cord in four cases. All patients had ill-defined decreased signal on T1-weighted and increased signal changes on T2-weighted sections within the cord. In some, this was associated with cord expansion. Airway narrowing was a common finding. Disc dehydration and the classical platyspondyly with antero-inferior beaking of the vertebral bodies was seen.

Symptomatic spinal hemangiomas in association with cutaneous hemangiomas. A case report.

STUDY DESIGN: This case report describes a patient with associated vertebral and peripheral vascular malformations presenting with a painful scoliosis. OBJECTIVES: To treat the vertebral osseous lesion successfully with embolization. SUMMARY OF BACKGROUND DATA: Although vertebral vascular malformations are well described, the association with peripheral lesions is uncommon. When associated peripheral vascular malformations occur, they are usually in tissues derived from the same embryonic segment, which was not the case in this instance. METHODS: After investigation with angiography, this patient's vertebral osseous lesion was treated by embolization. RESULTS: This patient's pain has been abolished since embolization. Her scoliosis has not progressed during follow-up. CONCLUSIONS: This case illustrates the association between spinal and peripheral vascular malformations, and that this association is not always metameric. It highlights the fact that invasive procedures other than surgery are a valuable part of the therapeutic armamentarium.