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Biomedical subjects

S A Renowden

Publications and source records attributed to S A Renowden.

At least 19 recordsLinked to original sources
PubMed2005

Some patients with multiple sclerosis have neurovascular compression causing their trigeminal neuralgia and can be treated effectively with MVD: report of five cases.

The role of trigeminal ganglion percutaneous injection and radio-frequency lesioning procedures for the treatment of trigeminal neuralgia (TGN) in multiple sclerosis (MS) is well established. There is general acceptance that microvascular decompression (MVD) cannot be an appropriate treatment due to the view that the underlying aetiology is a demyelinating plaque affecting the root entry zone of the trigeminal pathway. Recently, MR-imaging has been used in the preoperative investigation of this group of patients demonstrating that neurovascular compression can occasionally be the responsible mechanism and that MVD can be the treatment of choice. We present five cases with MS and TGN. All the patients had failed to respond to medical treatment or percutaneous procedures. Magnetic resonance imaging demonstrated evidence of neurovascular compression in four cases. All the patients underwent MVD. Postoperatively four of the five patients made an uncomplicated recovery, were pain-free and fully satisfied with the result (mean follow-up 38.75 months; range 8-59 months). One patient developed recurrent pain 1 week following surgery and went on to have a total sensory rhizotomy. TGN in MS can be caused by neurovascular compression, which may be identified on MR-imaging. MVD has offered satisfactory short-term outcome for at least 2 years and does not inflict sensory loss. Longer follow-up will determine whether the outcome in MS patients will be as successful as in the TGN patients who do not suffer from MS.

Adult↗
PubMed2003

How accurate is magnetic resonance angiography in predicting neurovascular compression in patients with trigeminal neuralgia? A prospective, single-blinded comparative study.

Ninety-two patients with trigeminal neuralgia (TGN) were investigated prior to posterior fossa surgery with magnetic resonance imaging (MRI) and contrast-enhanced magnetic resonance angiography (MRA). The preoperative investigation was matched to one consultant neuroradiologist (co-author) who was blinded to the side of symptomotology. The imaging results were compared with the operative findings in all patients. In 76 patients MRA showed present neurovascular compression in accordance with surgical findings. Eight cases had no compression either on MRA or intraoperatively. Eight predictions of no compression were false and there was no false positive. Based on surgical findings, the sensitivity of MRA was 90.5% and the specificity 100%. In 19 cases MRA predicted bilateral compression of the trigeminal nerves. Only two cases had clinically bilateral TGN. We conclude that MRA with gadolinium enhancement is an extremely sensitive and specific method for demonstrating compression in TGN. As a result posterior fossa surgery can be recommended with confidence, and microvascular decompression remains the treatment of choice for TGN at the authors' centre.

Contrast Media↗
PubMed1996

Pictorial review: MR imaging of neuronal migration anomalies.

Neuronal migration anomalies form a spectrum of congenital brain malformations with a variety of clinical manifestations. The widespread use of MRI in the investigation of neurological symptoms, and particularly in the imaging of epilepsy, has made the correct recognition and interpretation of these disorders important. This pictorial summary describes the typical clinical features and the MR appearances of this group of conditions. For a more detailed review which includes pathological correlation, the reader should refer to an excellent article by Barkovitch and colleagues (Barkovitch A.J., Gressens P, Evrard P. Formation, maturation and disorders of brain neocortex.

Brain↗
PubMed1995

Spontaneous intracranial hypotension.

The clinical features and radiological appearances of spontaneous intracranial hypotension are described in three patients and the medical literature is reviewed. Awareness of this condition and its differentiation from more sinister meningitic processes is important to avoid unnecessary invasive investigations and to allow prompt diagnosis and effective treatment.

Adult↗
PubMed1995

Embolisation of recently ruptured intracranial aneurysms.

Patients with subarachnoid haemorrhage due to the rupture of aneurysms unsuitable for craniotomy and clipping have been treated by coil embolisation within three weeks. Sixty nine of 75 consecutive patients were successfully treated. Procedure related complications occurred in 10 patients, resulting in permanent neurological deficits in three and one death (4.8%). The Glasgow outcome scores at six weeks were 53 grade 1, seven grade 2, four grade 3, and five grade 5. These results are comparable with surgical series despite a high proportion of aneurysms in the posterior cerebral circulation.

Adult↗
PubMed1995

Thrombosis in giant basilar tip aneurysms during coil embolization.

Two patients with giant basilar tip aneurysms underwent coil embolization, one with both platinum fiber and platinum Guglielmi detachable coils and the other with Guglielmi detachable coils only. In both cases, spontaneous intraaneurysmal thrombosis occurred outside the coil mass, presumably a result of disruption of the intraaneurysmal flow pattern.

Adult↗
PubMed1995

Selective amygdalohippocampectomy for hippocampal sclerosis: postoperative MR appearance.

PURPOSE: To analyze the anatomic consequences of selective amygdalohippocampectomy (AH) in patients with hippocampal sclerosis and to correlate the clinical outcome with the MR appearance. METHODS: Seventeen patients were examined with clinical and neuropsychologic examination and cranial MR after AH (7 transcortical AH, 10 trans-Sylvian AH). The clinical and neuropsychologic outcomes after AH were compared with those of anterior lobectomy (ATL). RESULTS: There was no significant difference in seizure cure between transcortical or trans-Sylvian AH and ATL. However, patients with left AH fared significantly better in terms of verbal IQ and nonverbal memory when compared with those with left ATL. Verbal memory and cognition were not significantly different in the two AH groups. Variable amounts of hippocampal and amygdala remnants were found in both AH groups and did not correlate with seizure cure. White matter change consistent with gliosis probably secondary to wallerian degeneration was demonstrated in the anterior temporal lobe to a mean distance of 4.5 cm after transcortical AH and to a lesser degree as a consequence of trans-Sylvian AH. Nine patients (53%) (4 transcortical All, 5 trans-Sylvian AH) demonstrated wallerian degeneration in the optic radiations after surgery. All had incomplete contralateral quadrantanopia. CONCLUSIONS: There is more secondary damage to the temporal lobe after AH than was previously recognized. The extent of hippocampal and amygdala resection in AH do not seem to be directly related to seizure cure. Visual field defects are common in AH because of the anterior but variable course of the optic radiations

Adolescent↗
PubMed1994

The value of MRI in angiogram-negative intracranial haemorrhage.

In one year, cerebral angiograms were performed for intracranial haemorrhage (ICH) on 334 patients. No cause for haemorrhage could be identified in 41 (12%), 30 of whom had predominantly subarachnoid (SAH) and 11 predominantly parenchymal haemorrhage (PH). These patients were prospectively examined by cranial MRI 1-6 weeks after the ictus. The MRI studies were positive in 7 patients (17%). In the 30 patients examined after SAH, 2 studies were positive, showing an aneurysm in one case and a brain stem lesion of uncertain aetiology in the other. In those examined after PH, cavernous angiomas were shown in 2, a tumour in 1 and a vascular malformation in another; useful diagnostic information was thus obtained in 36% of this group.

Adult↗
PubMed1994

Unusual magnetic resonance and neuropathological findings in hemimegalencephaly: report of a case following hemispherectomy.

Hemimegalencephaly is a rare disorder manifest by early epilepsy, mental retardation and hemiplegia. The neuropathology has been described in only 15 cases to date. The present case provides a further description of the pathology in a hemispherectomy specimen and shows unusual features, including cystic breakdown of the white matter possibly related to the long duration of the features, including cystic breakdown of the white matter possibly related to the long duration of the disease; the subject was 13 years older than previously documented cases. MRI findings were also unusual in showing mass effect and ventricular compression in the affected hemisphere, features not previously described in hemimegalencephaly.

Adolescent↗
PubMed1993

The effective use of magnetic resonance imaging in the diagnosis of acoustic neuromas.

The diagnostic approach to acoustic neuromas is complex but these tumours are infrequent in patients even with a suggestive clinical picture. Easy access to an efficient, reliable and cost effective investigation is desirable. Magnetic resonance imaging is now the imaging modality of choice and this paper shows that it may be used effectively as the sole investigation. T2-weighted (T2W) fast spin echo axial images taking 1 min 37 s to acquire were compared with T1-weighted (T1W) gadolinium-enhanced axial images, taking 5 min 11 s to acquire, in 157 patients. The T2W images were satisfactory alone in 43% of patients and allowed confident diagnosis of seven of the nine acoustic neuromas. Partial volume artefact and CSF flow artefact resulted in equivocal examinations in the remaining patients. Using both sequences in every patient, imaging time was 7 min 41 s and at least 40 patients could be examined in 1 day, thus ensuring efficient patient throughput. We suggest that T2W fast spin echo axial images be routinely obtained and that only when they are equivocal should T1W gadolinium-enhanced axial sequences be employed.

Adolescent↗
PubMed1993

Case report: spontaneous thrombosis of a spinal dural AVM (Foix-Alajouanine syndrome)--magnetic resonance appearance.

We describe a patient with a classical presentation of a spinal dural arteriovenous malformation which probably underwent spontaneous thrombosis. This is known as the Foix-Alajouanine syndrome. The diagnosis was not made in this patient until after cord infarction had occurred. The clinical and radiological features of spinal vascular malformations are reviewed because prompt treatment may halt or even reverse their neurological manifestations.

Arteriovenous Malformations↗
PubMed1993

Study of the anatomy of the extradural region using magnetic resonance imaging.

We have studied magnetic resonance images of the lumbar spine of 39 subjects to examine the anatomy of the lumbar extradural region. The segmental nature of the posterior extradural region at each lumbar level may explain reports of easier cranial passage of extradural catheters introduced by the paramedian approach. This approach may thus provide a more reliable route for rapid introduction of an extradural catheter during the needle-through-needle, combined spinal-extradural technique.

Adolescent↗
PubMed1993

Isolated atraumatic third nerve palsy: clinical features and imaging techniques.

We have reviewed 34 consecutive patients imaged for an isolated third nerve palsy over a 2-year period. With pupil sparing the third nerve palsy was most often due to ischaemic microvascular disease. The commonest cause of a third nerve palsy with pupillary involvement was a posterior communicating artery aneurysm. Clinical features such as speed of onset, pain and completeness of palsy were not reliable in the diagnosis of either the nature or the location of the cause. Pupillary involvement was however often associated with a compressive lesion. Imaging along the whole course of the nerve is recommended for adequate evaluation.

Adult↗
PubMed1992

Duplex and colour flow sonography in the diagnosis of post-biopsy arteriovenous fistulae in the transplant kidney.

Arteriovenous fistulae are a common sequel to percutaneous biopsy of the transplant kidney. The majority close spontaneously, but a proportion progress and may require embolization or surgical closure. They are characterized by a very pulsatile (arterialized) venous flow. The arteries sometimes demonstrate a low resistive index and/or high velocities, but normal values may be encountered. On colour flow Doppler the most characteristic appearance is a mosaic of colour due to a combination of tissue vibration and turbulence.

Adolescent↗