Case report: Intracranial meningeal melanocytoma: a cause of high signal on T1- and low signal on T2-weighted MRI.
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Adult↗
Biomedical subjects
R D Laitt
Publications and source records attributed to R D Laitt.
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.
Adult↗
Necrotising orbital cellulitis.
PURPOSE: To report 2 cases of severe necrotising orbital cellulitis which illustrate the need for aggressive surgical management to prevent blindness. METHODS: The case records of 2 patients with necrotising orbital cellulitis were reviewed. RESULTS: Both patients had orbital cellulitis associated with sinusitis. Each case was characterised by the rapid development of severe systemic toxicity, extensive soft tissue necrosis and abscess formation. One patient developed panophthalmitis and the eye had to be eviscerated. The other patient underwent repeated surgical drainage of multiple orbital abscesses. This led to resolution of the infection and preservation of vision. CONCLUSIONS: Atypical rapidly progressive necrotising orbital cellulitis may occasionally be encountered. In such cases, aggressive surgical drainage of orbital abscesses is crucial to prevent blindness and death.
Abscess↗
Significance of CSF area measurements in cervical spondylitic myelopathy.
Mild clinical myelopathy can occur without cord compression, and asymptomatic cord compression seen on MRI is common. The aim of this study was to ascertain the MRI features which best correlate with early clinical myelopathy. The study was conducted on three groups: group A, 20 patients with clinical myelopathy and MRI evidence of cervical spondylosis; group B, 20 patients without myelopathy, but with other clinical and MRI evidence of cervical spondylosis; and group C, 10 normal volunteers with no MRI evidence of spondylosis. The cross-sectional area (CSA) of the spinal cord (SP-CSA), spinal canal (SC-CSA) and CSF space (CSF-CSA) were measured on T1-weighted axial images at the level of the most severe spinal canal stenosis. The severity of myelopathy was assessed using a simple scoring system giving a score from 0 (normal) to 11 (severe). Subjective demonstration of cord compression on sagittal images was an insensitive indicator of clinical myelopathy. All three measures of cross-sectional area were significantly smaller in Group A than in B (p<0.01). The reduction in SP-CSA was the only independent prognosticator for severity of myelopathy (p<0.005) accounting for 63% of the variation in myelopathy score. All three variables showed a significant correlation with the presence of myelopathy (p<0.01); however, logistic regression analysis showed a decrease in CSF-CSA to be the only independent significant prognosticator of the presence of clinical myelopathy (p<0.02). Reduction of the CSF space to less than 0.7 cm2 was associated with a 90% chance of clinical myelopathy (specificity 83%).
Adult↗
Magnetic resonance imaging in the investigation of sensorineural hearing loss: is contrast enhancement still necessary?
High resolution T2-weighted magnetic resonance (MR) imaging has been proposed as a rapid, inexpensive means of investigating patients with sensorineural deafness, particularly to exclude vestibular schwannomas. Whether the accepted 'gold standard' of contrast-enhanced T1-weighted images can be omitted, however, remains controversial. Over a 22-month period the use of axial turbo-spin echo T2-weighted images (T2W) were prospectively compared with contrast-enhanced T1-weighted spin echo scans in the evaluation of 513 patients presenting with audiovestibular symptoms. A 2-D T2W turbo spin echo (TSE) sequence with 3 mm slices was used in 340 patients while a 3-D sequence with overlapping 1 mm slices was used in 173 patients. The T2-weighted image findings were documented and subsequently compared with contrast-enhanced images. With the 2-D sequence 24 patients (25 lesions) had internal auditory meatus (IAM)/cerebello-pontine angle (CPA) masses identified by contrast-enhanced T1-weighted images, all of which were seen on the T2-weighted TSE sequence; there was one false positive 'mass' on the T2-weighted scans and one false negative case of IAM dural enhancement on T1-weighted imaging; six were considered normal initially on the T2-weighted images although three were subtly abnormal in retrospect. With the 3-D sequence three acoustic neuromas were all identified correctly with no false positive and only one false negative result (labyrinthitis). The 2-D and 3-D images were judged technically inadequate for clinical assessment in 15 and nine per cent respectively. We conclude that mass lesions of the IAM/CPA can be reliably identified on T2W TSE imaging but labyrinthine lesions may be missed without contrast enhancement. This is of particular importance in planning the management of neurofibromatosis type 2. Non-neoplastic disorders of the inner ear are also likely to be missed.
Adolescent↗
The role of MR angiography in the pretreatment assessment of intracranial aneurysms: a comparative study.
BACKGROUND AND PURPOSE: With developments in coil technology, intracranial aneurysms are being treated increasingly by the endovascular route. Endovascular treatment of aneurysms requires an accurate depiction of the aneurysm neck and its relation to parent and branch vessels preoperatively. Our goal was to estimate the clinical efficacy of MR angiography (MRA) in the pretreatment assessment of ruptured and unruptured intracranial aneurysms. We compared MRA source data (axial acquired partitions), multiplanar reconstruction (MPR) of these data, as well as maximum intensity projection (MIP) and 3D-isosurface images with intraarterial digital subtraction angiography (IA-DSA). METHODS: The study was performed in 29 patients with 42 intracerebral aneurysms. The MRA data were examined in four different forms--as axial source data, MPR images of the source data, and MIP and 3D isosurface--rendered images. A composite standard of reference for each aneurysm was then constructed using this information together with the IA-DSA findings by looking at aneurysm detection rate, aneurysm morphology, neck interpretation, and branch vessel relationship to the aneurysm. All techniques, including conventional IA-DSA, were then scored independently on a five-point scale from 1 (non diagnostic) to 5 (excellent correlation with the standard of reference) for each of the aneurysm components as compared with the composite picture. An overall score for each technique was also obtained. RESULTS: Of the 42 aneurysms examined, 34 were small (<10 mm), six were large (10-25 mm), and two were giant (>25 mm). Three aneurysms were not detected with MRA. These were smaller than 3 mm and either in an anatomically difficult location (middle cerebral artery bifurcation) or obscured by adjacent hematoma. Two large aneurysms were depicted as undersized by IA-DSA owing to the presence of intramural thrombus shown by MRA axial source data. IA-DSA received the highest scores overall and in three of the four subgroups. Three-dimensional isosurface reconstructions scored higher than did IA-DSA for depiction of the aneurysm neck, although this difference was not significant. The MPR and 3D-isosurface images were comparable to those of IA-DSA in all categories. MPR images were particularly useful for defining branch vessels and the aneurysm neck. MIP images scored poorly in all subgroups (P < .005) compared with IA-DSA findings, except for in aneurysm detection. Source data images were significantly inferior to those of IA-DSA in all categories (P < .005). CONCLUSION: MRA is currently inferior to IA-DSA in pretreatment assessment of intracranial aneurysms, and can miss small lesions (<3 mm). It can, however, provide complementary information to IA-DSA, particularly in anatomically complex areas or in the presence of intramural thrombus. If MRA is used in aneurysm assessment, a meticulous technique with reference to both axial source data and MPR is mandatory. The axial source data should not be interpreted in isolation. Three-dimensional isosurface images are comparable to those of IA-DSA and are more reliable than are MIP images, which should be interpreted with caution.
Adult↗
Demonstration of cerebral perfusion abnormalities in moyamoya disease using susceptibility perfusion- and diffusion-weighted MRI.
We describe the use of diffusion-weighted imaging and perfusion MRI using a contrast-medium bolus in the preoperative investigation for young man presenting with a cerebral ischaemic episode as a manifestation of moyamoya disease.
Adolescent↗
Constructive interference in steady-state 3D Fourier-transform MRI in the management of hydrocephalus and third ventriculostomy.
We describe the use of three-dimensional Fourier transform constructive imaging in the steady state (CISS) MRI in the assessment of patients with hydrocephalus. We have found it of value both as a diagnostic investigation and in the follow-up of patients treated by third ventriculostomy.
Adolescent↗
Familial tumoral calcinosis: association with cerebral and peripheral aneurysm formation.
Two siblings with histologically and radiologically proven tumoral calcinosis presented with cerebral and peripheral aneurysms. The brother died of a ruptured subclavian artery aneurysm after surgical repair of brachial, iliofemoral and coeliac axis aneurysms. Magnetic resonance and catheter angiography in the sister demonstrated marked carotid dysplasia and a left ophthalmic segment aneurysm, not amenable to treatment. We believe this is the first reported case of familial aneurysms in association with tumoral calcinosis.
Aneurysm↗
Use of single-slice thick slab phase-contrast angiography for the diagnosis of dural venous sinus thrombosis.
The aim of this study was to examine the reliability of single-slice phase-contrast angiography (SSPCA) as a rapid technique for the investigation of suspected dural venous sinus occlusion. Images were obtained on 25 normal volunteers to document the accuracy of SSPCA in the demonstration of slow flow states. Normal volunteers were imaged using sagittal and coronal SSPCA (slice thickness 13 cm, matrix 256 x 256, TR 14 ms, TE 7 ms, flip angle 20 degrees, peak velocity encoding rate 30 cm/s). Sinus patency and flow rate were confirmed by measurement of flow in the superior sagittal and transverse sinuses using quantified single-slice phase difference images. Imaging was performed in 50 patients undergoing routine brain scans in order to determine the optimal slice orientation for clinical use. Twenty-one patients with suspected dural venous sinus thrombosis were also investigated with SSPCA and the diagnosis confirmed by one or more alternative imaging techniques. Imaging time was 29 s per acquisition and image quality was good in all cases. Variations in dural sinus patency and flow in normal volunteers were accurately predicted by SSPCA (kappa = 0.92). Use of a single angulated slice (130 mm thick, para-sagittal image angled 30 degrees towards coronal and 30 degrees towards transverse) provided sufficient separation of right- and left-sided venous structures to allow use of a single projection. The presence and extent of sinus occlusions in 14 patients and the absence of thrombosis in 7 were accurately identified by SSPCA. Sensitivity and specificity in this limited study were both 100%. The SSPCA technique takes less than 30 s and provides a reliable and rapid technique for the diagnosis of dural venous sinus thrombosis.
Adult↗
MRI and CT in a case of pituitary abscess.
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Abscess↗
Tinnitus as the presenting symptom in a case of Lhermitte-Duclos disease.
Dysplastic gangliocytoma or Lhermitte-Duclos disease (LDD) is a hamartomatous malformation of the cerebellar hemisphere that usually presents with signs of increased intracranial pressure or symptoms of cerebellar dysfunction. In this paper, we report a case of LDD presenting with tinnitus, and postulate a probable mechanism for this unusual presentation.
Cerebellar Neoplasms↗
Comparison of three-dimensional visualization techniques for depicting the scala vestibuli and scala tympani of the cochlea by using high-resolution MR imaging.
BACKGROUND AND PURPOSE: Cochlear implantation requires introduction of a stimulating electrode array into the scala vestibuli or scala tympani. Although these structures can be separately identified on many high-resolution scans, it is often difficult to ascertain whether these channels are patent throughout their length. The aim of this study was to determine whether an optimized combination of an imaging protocol and a visualization technique allows routine 3D rendering of the scala vestibuli and scala tympani. METHODS: A submillimeter T2 fast spin-echo imaging sequence was designed to optimize the performance of 3D visualization methods. The spatial resolution was determined experimentally using primary images and 3D surface and volume renderings from eight healthy subjects. These data were used to develop the imaging sequence and to compare the quality and signal-to-noise dependency of four data visualization algorithms: maximum intensity projection, ray casting with transparent voxels, ray casting with opaque voxels, and isosurface rendering. The ability of these methods to produce 3D renderings of the scala tympani and scala vestibuli was also examined. The imaging technique was used in five patients with sensorineural deafness. RESULTS: Visualization techniques produced optimal results in combination with an isotropic volume imaging sequence. Clinicians preferred the isosurface-rendered images to other 3D visualizations. Both isosurface and ray casting displayed the scala vestibuli and scala tympani throughout their length. Abnormalities were shown in three patients, and in one of these, a focal occlusion of the scala tympani was confirmed at surgery. CONCLUSION: Three-dimensional images of the scala vestibuli and scala tympani can be routinely produced. The combination of an MR sequence optimized for use with isosurface rendering or ray-casting algorithms can produce 3D images with greater spatial resolution and anatomic detail than has been possible previously.
Adult↗
Optic neuritis: MR imaging with combined fat- and water-suppression techniques.
PURPOSE: To examine the benefits of combined fat- and water-suppressed T2-weighted magnetic resonance (MR) images in the diagnosis of optic neuritis. MATERIALS AND METHODS: MR imaging was performed with a 1.5-T unit in five healthy volunteers and 18 patients (21 nerves). All patients had abnormalities of visual evoked potentials and fulfilled the clinical criteria for the diagnosis of optic neuritis. Imaging was performed within 4 weeks of diagnosis (n = 12) or between 3 and 6 months after diagnosis (n = 6). Coronal images were obtained throughout the course of the optic nerve with use of three sequences: (a) short inversion time inversion recovery with fast spin-echo (SE) acquisition, (b) selective partial inversion-recovery (SPIR) prepared T2-weighted fast SE acquisition, and (c) SPIR-fluid-attenuated inversion recovery (FLAIR) with fast SE acquisition. RESULTS: Neuritic segments were demonstrated in all 21 symptomatic nerves. The extent of neuritic involvement (number of images showing abnormality) was significantly greater with the SPIR-FLAIR sequence (P < .01). The contrast ratio between neuritic optic nerve and orbital fat, normal nerve, and cerebral spinal fluid was significantly greater with SPIR-FLAIR than with the other sequences (P < .001). SPIR-FLAIR images also improved demonstration of optic nerve atrophy in chronic neuritis when compared with the other sequences. CONCLUSION: The SPIR-FLAIR sequence offers important advantages over current methods in the demonstration of optic neuritis.
Adult↗
Hereditary spinal osteochondromas in diaphyseal aclasia.
We present cases of cervical cord compression in father and son with diaphyseal aclasia. Both patients were investigated with plain radiography, CT and MRI. We believe this to be the first report of spinal cord compression in first-degree relatives with diaphyseal aclasia.
Adolescent↗
Blunt carotid arterial trauma.
Blunt injury to the carotid arteries in the neck, either by direct or indirect forces, is rare but may produce a devastating outcome with long term morbidity. Injury results in either dissection of the vessel wall or pseudoaneurysm formation. Secondary thromboembolic disease results in cerebral infarction. In a seven year period, from April 1987 to April 1994, 2024 patients with blunt injury to the head and neck were admitted to our institution. In this group eight patients (0.4%) were identified with injury to the carotid arteries, seven with dissection and one with pseudoaneurysm formation. Injury was caused by either hyperextension or lateral hyperflexion of the neck. External signs of trauma to the neck were absent in three patients. In all patients there was an associated head injury. Three suffered transient loss of consciousness and a fourth had a transient ischaemic attack 36 h after the injury. CT brain scans performed at the time of initial injury in these patients were all normal. The remaining four patients had no neurological deficit at initial presentation. In no case was injury to the carotid artery suspected. Focal neurological signs and symptoms developed in all cases following a variable latent period ranging from 4 h to 75 days. CT or MRI at this time revealed areas of cerebral infarction. Diagnosis of carotid injury was made at angiography in all cases. These lesions are treatable if diagnosed prior to the development of extensive infarction. Patients developing focal neurological signs secondary to cerebral infarction after a latent period following head and neck trauma should therefore be considered as having a vascular lesion in the neck and referred for urgent cerebral angiography.
Adult↗
Cystic optic nerve meningioma presenting with acute proptosis.
A 37-year-old woman presented with acute left-sided proptosis. Magnetic resonance imaging demonstrated a solid intraconal mass lesion with an associated 'capping' cyst. This lesion was resected and found on histological examination to be optic nerve sheath meningioma. Small perineural cysts have been reported with optic nerve sheath meningioma but we believe this to be the first reported case of a large peritumoral cyst associated with this type of mass lesion. We speculate on the aetiology of the cyst and the associated acute proptosis.
Acute Disease↗
Late aggressive meningioma following prophylactic cranial irradiation for acute lymphoblastic leukaemia.
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Cranial Irradiation↗