CNS demyelination associated with immune dysregulation and a novel CTLA-4 variant

Background:

The cytotoxic T-lymphocyte antigen-4 (CTLA-4) pathway acts as a negative immune regulator of T-cell activation and promotes self-tolerance.

Case:

We report the first case of biopsy-proven central nervous system inflammatory demyelination in the context of primary immunodeficiency and a novel CTLA-4 variant.

Conclusion:

This case has significant implications for the development of novel treatments for autoimmune conditions including multiple sclerosis and further emphasises the need for caution with clinical use of CTLA-4 immune checkpoint inhibitors in those with a history of inflammatory demyelination.

Internal Carotid Artery Test Balloon Occlusion Using Single Photon Emission Computed Tomography Scan in the Management of Complex Cerebral Aneurysms and Skull Base Tumors: A 20-Year Review

BACKGROUND

Test balloon occlusion (TBO) is important in the management of complex cerebrovascular and skull base lesions when permanent occlusion (PO) of a parent artery may be indicated. Several adjuncts may be used to increase the sensitivity of TBO to predict whether PO will be tolerated. This is an observational study to evaluate the utility of internal carotid artery (ICA) TBO using single photon emission computed tomography (SPECT) scan in the management of complex vascular pathology and skull base tumors.

METHODS

All TBO procedures performed over a 20-year period were analyzed. Clinical assessment and angiographic collateral flow were combined with semi-quantitative cerebral blood flow analysis using ^99mTc hexamethylpropylene-amine oxime SPECT scan during ICA TBO. Evaluation of collateral circulation after TBO, and the complications of TBO and the safety of PO after successful TBO were evaluated.

RESULTS

Eighty-three patients underwent TBO without complication. Of 45 patients with satisfactory TBO, 28 proceeded to PO. Three patients developed transient ischemic symptoms thought to be embolic in origin. Thirty-eight patients had unsatisfactory TBO, of whom 15 required PO accompanied by a bypass procedure. Forty patients in the series did not undergo permanent vessel occlusion.

CONCLUSIONS

SPECT scan-enhanced TBO is an important component of the management of complex vascular pathology and skull base tumors, permitting safe PO of the parent vessel and definitive treatment of the main pathology.

Erdheim-Chester disease: 25-year history with early CNS involvement

We report a case of Erdheim-Chester disease (ECD) with a 25-year history following initial presentation with diabetes insipidus and brainstem involvement. The exceptionally long history is particularly notable, given that ECD is a life-threatening disorder and there is a recognised association between central nervous system involvement and poor outcome. The case is a timely reminder of the presenting features of the condition, given the emergence of potential new treatment options.

Ovarioleukodystrophy due to EIF2B5 mutations

Ovarioleukodystrophy-the co-occurrence of leukodystrophy and premature ovarian failure-is a rare presentation now recognised to be part of the clinical spectrum of vanishing white matter disease. We describe a woman with epilepsy and neuroimaging changes consistent with leukoencephalopathy who presented with non-convulsive status epilepticus after starting hormone replacement therapy in the context of premature ovarian failure. Genetic testing confirmed her to be a compound heterozygote for EIF2B5 mutations; the gene encodes a subunit of eukaryotic translation initiation factor 2B. Mutations in EIF2B1-5 result in vanishing white matter disease. We highlight the importance of ovarian failure as a diagnostic pointer to eukaryotic translation initiation factor 2B (eIF2B)-related ovarioleukodystrophy and present a brief literature review of ovarioleukodystrophy.

Tumefactive demyelination presenting during bevacizumab treatment

We report the emergence of tumefactive demyelination during treatment with intravitreal bevacizumab (Avastin). This is of particular significance given that bevacizumab is currently being assessed as a potential treatment option for neuromyelitis optica, another demyelinating condition.

The negative predictive value of CT angiography in the setting of perimesencephalic subarachnoid hemorrhage

Background

Perimesencephalic subarachnoid hemorrhage (PMSAH) is only rarely associated with a ruptured cerebral aneurysm and CT angiography (CTA) has very good sensitivity and specificity for aneurysm detection. The necessity for invasive imaging with digital subtraction angiography (DSA) is therefore debatable. We chose to assess the negative predictive value (NPV) of CTA in a series of patients with PMSAH treated at our institution over a 9-year period.

Methods

We retrospectively assessed the diagnostic yield of DSA after initial negative CTA in patients with a PMSAH pattern defined as blood centered anterior to the midbrain and/or pons within the pre-pontine or interpeduncular cistern with possible quadrigeminal or ambient cistern extension; possible extension into the basal parts of the sylvian fissures but not the lateral sylvian fissures; possible extension to the cisterna magna but not centered on the cisterna magna; and possible extension into the fourth ventricle and occipital horns of the lateral ventricles.

Results

Using this definition of PMSAH, of 72 patients, one patient showed a potentially significant finding on DSA that was not demonstrated on initial CTA (NPV 98.61% (95% CI 92.47% to 99.77%)). However, when cisterna magna extension was excluded from the definition of PMSAH, no false negative CTAs in 56 patients were encountered (NPV 100% (95% CI 93.56% to 100.00%)).

Conclusions

The NPV of normal CTA for an arterial abnormality in patients with PMSAH is high and our results therefore question the role of invasive imaging. The findings also suggest that a prospective study designed to clarify the necessity of performing DSA in this population would be feasible.

Is long-term follow-up of adequately coil-occluded ruptured cerebral aneurysms always necessary? A single-center study of recurrences after endovascular treatment

PURPOSE

Aneurysm recurrence following coil occlusion is well recognized. However, there is controversy as to how long these patients should be followed up after coiling to detect reopening. We aimed to identify the rate of late reopening and the risk factors for reopening in a large single-center cohort of ruptured aneurysms that appeared adequately occluded at 6 months. We also aimed to assess whether rates of recurrence have altered over time with improving coil and angiographic technology.

METHODS

Patients treated between 1996 and 2010 were assessed and those with both 6-month initial and subsequent long-term follow-up with either digital subtraction angiography or magnetic resonance angiography were included. Aneurysms were stratified by features such as size, neck width, anatomical location and time of treatment: 1996-2005 (cohort 1) and 2006-2010 (cohort 2). ORs for risk of recurrence were calculated for aneurysm features and rates of recurrence in each cohort were compared using a χ(2) test.

RESULTS

437 patients with 458 adequately occluded aneurysms at 6 months had mean long-term follow-up of 31 months; 57 (12.4%) were large (≥ 10 mm) and 104 (22.7%) were wide-necked (>4 mm). Nine aneurysms (2%) showed significant late anatomical deterioration whereby retreatment was considered or undertaken. The risk was greater for large aneurysms (≥ 10 mm) (OR 15.61, 95% CI 3.79 to 64.33, p=0.0001) or wide-necked aneurysms (>4 mm) (OR 12.70, 95% CI 2.60 to 62.13, p=0.0017). The frequency of significant late anatomical deterioration and retreatment was also less common in those treated in cohort 2 (p<0.05). No completely occluded aneurysm at 6 months demonstrated significant late recurrence.

CONCLUSIONS

Most aneurysms adequately occluded at 6 months did not show evidence of late recurrence. Large and wide-neck aneurysms are, however, at greater risk of later recurrence.

Endovascular therapy in hyperacute ischaemic stroke: history and current status

This is a literature review on to the use of endovascular therapy in hyperacute ischaemic stroke secondary to large vessel occlusion (LVO). The prognosis for LVO is generally poor and the efficacy of intravenous tissue plasminogen activator (IV TPA) in the treatment of this subtype of stroke is questionable. It is well documented that recanalisation is associated with improved outcomes but IV TPA has limited efficacy in LVO recanalisation and the complication rates are higher for IV TPA in this stroke subset. Improved recanalisation rates have been demonstrated with intra-arterial TPA and first and second generation mechanical techniques but the rate of favourable outcome has not overtly mirrored this improvement. Several controversial trials using these early techniques have recently been published but fail to reflect modern practice which centres on the use of stent-retriever technology. This has been proven to be superior to older techniques. Not only are recanalisation rates higher, but the speed of recanalisation is greater and clinical results are improved. Multiple observational studies demonstrate consistently high rates of LVO recanalisation; TICI 2b/3 in the order of 65-95% and, rates of favourable outcome (mRS 0-2) in the order of 55% (42.5-77%) in clinically moderate to severe stroke with complicating symptomatic haemorrhage in the order of 1.5-15%. A major factor determining outcome is time to treatment but success has been demonstrated using these devices with bridging therapy, after IV TPA failure or as a stand-alone treatment.

Endovascular treatment of 300 consecutive middle cerebral artery aneurysms: clinical and radiologic outcomes

BACKGROUND AND PURPOSE

There is controversy as to the best mode of treating MCA aneurysms. We report the results of a large endovascular series of patients treated at our center.

MATERIALS AND METHODS

This study was a retrospective analysis of a prospectively acquired data base. All patients with saccular MCA aneurysms treated between November 1996 and June 2012 were included. World Federation of Neurosurgical Societies grade, aneurysm site, size, and aneurysm neck size were recorded, along with clinical outcome assessed with the Glasgow Outcome Scale and radiographic occlusion assessed with the Raymond classification at 6 months and 2.5 years.

RESULTS

A total of 295 patients with 300 MCA aneurysms were treated including 244 ruptured aneurysms (80.7%). The technical failure rate was 4.3% (13 patients). Complete occlusion or neck remnant was achieved in 264 (91.4%). Complications included rupture in 15 patients (5%), thromboembolism in 17 patients (5.7%), and early rebleeding in 3 patients (1%). Overall permanent procedural-related morbidity and mortality were seen in 12 patients (7.8%). Of the ruptured aneurysms, 189 (79.4%) had a favorable clinical outcome (Glasgow Outcome Scale score, 4-5). A total of 33 patients (13.6%) died. On initial angiographic follow-up, aneurysm remnant was seen in 18 aneurysms (8.1%). A total of 13 patients (4.3%) were re-treated.

CONCLUSIONS

Our experience demonstrates that endovascular treatment of MCA aneurysms has an acceptable safety profile with low rates of technical failure and re-treatment. Therefore, coiling is acceptable as the primary treatment of MCA aneurysms.

Endovascular treatment of children with cerebral venous sinus thrombosis: a case series

BACKGROUND

Cerebral venous sinus thrombosis is a potentially serious condition affecting 0.56 to 0.67 per 100,000 children annually; adverse outcomes are common. The standard of care is anticoagulation with heparin. A proportion of patients, however, remain in a severe clinical condition and in these, endovascular therapy is an alternative treatment. There is little published literature on the use of endovascular treatments in children with cerebral venous sinus thrombosis.

METHODS

We retrospectively reviewed case notes and imaging in a consecutive series of nine children treated using endovascular therapy after diagnosis of cerebral venous sinus thrombosis. Clinical presentation, decision to escalate therapy, methods of recanalization, and clinical outcome were assessed.

RESULTS

Nine children were treated (age range 18 months to 16 years). Diagnosis was made by computed tomography, computed tomography venography, magnetic resonance imaging, or magnetic resonance venography. Seven children were in a coma; one had signs of raised intracranial pressure with progressive cranial nerve palsies; and one was drowsy with a fluctuating hemiparesis. Eight children had been treated with heparin without improvement. Several endovascular methods were used including local tissue plasminogen activator, microguidewire and catheter disruption, balloon angioplasty, and thromboaspiration using the Penumbra device. Eight children had good functional outcomes. One child died as a result of uncontrolled intracranial hypertension secondary to cerebral venous sinus thrombosis.

CONCLUSION

Endovascular therapy may have a role in the treatment of cerebral venous sinus thrombosis in children when medical therapy has failed and the patient is in a poor clinical condition.

Thrombus length estimation in acute ischemic stroke: a potential role for delayed contrast enhanced CT

PURPOSE

Thrombus length has been shown to be an important determinant of recanalization using intravenous thrombolysis in hyperacute ischemic stroke. Various studies have attempted to quantify thrombus based on non-contrast CT (NCCT) or CT angiography (CTA). However, thrombus may not be seen on NCCT, and CTA may fail to delineate the distal extent of the thrombus. Contrast enhanced CT (CECT) following CTA can be used to estimate infarct core, but we investigated whether the angiographic data available on these images provided reliable information on thrombus length.

MATERIALS AND METHODS

15 consecutive patients, mean age 81 years (range 63-93), with terminal internal carotid artery or M1-middle cerebral artery occlusions underwent NCCT, CTA (bolus tracked technique), and CECT (acquired 80 s post initial CTA injection). Three radiologists assessed thrombus length on thin slice NCCT, and CTA and CECT.

RESULTS

CTA overestimated thrombus length relative to NCCT (p<0.001) and CECT (p<0.001). There was less difference between CTA and CECT estimation in patients with good collateral scores (p<0.05). There was good correlation between NCCT and CECT (Pearson's correlation coefficient=0.90, 95% CI 0.81 to 0.95, p<0.001). Inter-rater reliability assessed using intraclass correlation was 0.95 (95% CI 0.87 to 0.98) for NCCT and 0.98 (95% CI 0.94 to 0.99) for CECT.

CONCLUSIONS

CTA regularly overestimates thrombus length as the distal end of the thrombus is not delineated. This can be overcome through the use of a CECT acquisition which can reliably be used to estimate thrombus length.

A rare cause of neural foraminal widening

The differential diagnosis for lesions causing neural foraminal widening is vast. The majority are solitary benign peripheral nerve sheath tumours, such as neurofibromas or schwannomas. We present a case of a rare cause of neural foraminal expansion secondary to a posterior thoracic extradural angiolipoma. We describe the presence of chemical shift artefact on post gadolinium T1-weighted imaging as indirect evidence of a fatty component. This potentially important diagnostic sign may raise the suspicion of angiolipoma, especially in an isointense or hypointense dumbbell lesion on T1-weighted imaging, and has not been described previously in this context. Accurate radiological diagnosis of an angiolipoma is important to reduce unexpected haemorrhagic complications from biopsy or resection of the lesion.

Retained and fractured microcatheter: a cause of transient ischaemic attacks: endovascular management using carotid stents

A retained microcatheter is a rare complication of endovascular treatment of cerebral aneurysms. We describe such a case that was complicated by delayed microcatheter fracture within the internal carotid artery and subsequent thrombo-embolism resulting in transient ischaemic attacks. We also describe endovascular management of this complication through the use of several carotid stents.

Endovascular therapy for acute basilar artery occlusion: a review of the literature

Basilar artery occlusion is an infrequent form of acute stroke; clinical outcomes are heterogeneous, but the condition can be fatal. There is a lack of randomized controlled trial data in this field. Case series suggest that patients who are recanalized have much better outcomes than those who are not, and it is generally accepted that intra-arterial techniques achieve high rates of recanalization. Controversially, several studies, including a meta-analysis and registry-based investigation, that have compared intravenous thrombolysis (IVT) and intra-arterial treatment suggest similar outcomes. However, there are many potential sources of bias in each of these studies, precluding a firm conclusion. Indeed, there are many confounding factors that can influence the outcome including severity of presentation, site of occlusion, clot load, degree of collateral flow, timing of therapy, agent used for recanalization and dose of thrombolytic agent. Additionally, pretreatment infarct core imaging using diffusion-weighted imaging and the posterior circulation Acute Stroke Prognosis Early CT Score (pc-ASPECTS) scoring systems have been shown to predict outcome and therefore may be useful in selecting patients for aggressive therapy. Protocols combining intravenous agents such as glycoprotein IIb/IIIa receptor antagonists or thombolytics agents with intra-arterial techniques ('bridging' therapy) have shown encouraging improvements in neurological outcome and survival. Furthermore, initial case series describing the use of mechanical clot extraction devices or aspiration catheters suggest high rates of recanalization. What would be useful is a randomized trial comparing IVT, endovascular approaches and a combined IVT/endovascular approach. However, the small numbers of patients and multiple confounding factors are barriers to the development of such a trial.

Retreatment of previously embolized cerebral aneurysms: the risk of further coil embolization does not negate the advantage of the initial embolization

BACKGROUND AND PURPOSE

A significant minority of aneurysms treated by endovascular means undergo additional subsequent therapy to treat aneurysm recurrence. Our study was undertaken to determine the risk of additional coil embolization of aneurysms recurring following endovascular therapy.

MATERIALS AND METHODS

Patients were identified during a 10-year period from prospectively collated data bases at 2 different neuroscience institutions. Patient outcome was obtained from the data bases or the patient's neurosurgical records. Occlusion grade was assessed at the time of treatment and at follow-up angiography as complete, near-complete, or incomplete.

RESULTS

Of a total of 1834 aneurysms in 1631 patients, 100 aneurysms in 99 patients treated between January 1996 and December 2005 required additional coiling because of an enlarging remnant and subtotal occlusion. This comprised 6% of the patients treated and 8% of the total followed. Thromboembolic events complicated 3 retreatment procedures, but all 3 patients remain independent. Ninety-five patients were followed for 8-103 months (mean, 42.3 months) by conventional or MR angiography.

CONCLUSION

Coil embolization of aneurysm recurrences has a low complication rate and leads to satisfactory occlusion in most cases. The risk from additional coil embolization does not negate the advantage of the initial embolization.

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.

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.

Trigeminal neuralgia caused by microarteriovenous malformations of the trigeminal nerve root entry zone: symptomatic relief following complete excision of the lesion with nerve root preservation

OBJECT

Within a series of 341 consecutive patients who underwent posterior fossa surgery for trigeminal neuralgia (TN), in five the cause was found to be a microarteriovenous malformation (micro-AVM) located in the region of the trigeminal nerve root entry zone (REZ). The surgical management and clinical outcomes of these cases are presented.

METHODS

Patients were identified from a prospectively collected database of all cases of TN treated at one institution between 1980 and 2000. Presentation was clinically indistinguishable from TN caused by vascular compression. Preoperative imaging, including computerized tomography scanning (two cases) and magnetic resonance (MR) imaging and MR angiography (three cases), failed to demonstrate an AVM except for one case in which multiple abnormal vessels were identified in the trigeminal REZ on an MR image obtained using a 1.5-tesla magnet. All patients underwent a standard retromastoid craniotomy. In all cases a small AVM embedded in the trigeminal REZ was identified and completely excised, with preservation of the trigeminal nerve. All patients experienced immediate relief of pain following surgery. Postoperatively, in one patient a small pontine hematoma developed, resulting in permanent trigeminal nerve anesthesia in the V2 and V3 divisions. All patients were free from pain at a mean follow-up period of 30 months.

CONCLUSIONS

These rare lesions are usually angiographically occult, but may sometimes be identifiable on high-resolution MR images. Total microsurgical resection with nerve preservation is possible, although operative complications are relatively common, reflecting the intimate association between these lesions and the pons. Complete resection is advised not only for symptom relief, but also to eliminate the theoretical risk of pontine hemorrhage.

Middle cranial fossa arachnoid cysts: not always a benign entity

Arachnoid cysts are often discovered as incidental findings on cranial imaging. A rare manifestation is described in a child presenting acutely with symptoms and signs of raised intracranial pressure.

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.

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.

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.

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

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.

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.

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.

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.

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.

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.

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.

Renal transplant sonography: correlation of Doppler and biopsy results in cellular rejection

Seventy-one patients with allograft dysfunction had concomitant Doppler sonography and percutaneous biopsy. Forty-one had biopsy proven acute cellular rejection and eight had acute cellular rejection in combination with acute tubular necrosis. Real time ultrasonic appearance and various parameters of Doppler waveform were studied and compared with 30 controls who had a long period of stable function with no previous episodes of rejection or acute tubular necrosis (ATN). Morphological appearances were unhelpful in diagnosing rejection. A resistive index greater than 0.8 in the study group was highly specific for dysfunction but could not differentiate between acute rejection and ATN. However, two patients in the control group of normal transplants had a resistive index of 0.83. An early to mid diastolic notch was highly specific for acute rejection but of low sensitivity. It may be the only Doppler indication of cellular rejection and may be present when the resistive index is in the normal range.

The potential use of diuresis Doppler sonography in PUJ obstruction

Three cases of proven PUJ (pelvi-ureteric junction) obstruction in whom duplex Doppler sonography was performed are described. In one case, there was a duplex transplant kidney with PUJ obstruction of the lower pole moiety. The resistive index of an interlobar lower pole artery was markedly elevated compared to that of an artery in the upper unobstructed moiety. In the other two cases, the resistive index of interlobar arteries of native kidneys increased significantly following intravenous frusemide simultaneous with an increase in the degree of pelvicalyceal dilatation. It is proposed that diuresis Doppler sonography may provide additional diagnostic information in patients with PUJ obstruction, and that the method warrants further evaluation.

Osteomesopyknosis: a benign familial disorder of bone

A family with osteomesopyknosis is described. This condition is a rare benign bone dysplasia, characterized by patchy sclerosis predominantly involving the axial skeleton. The radiographic appearances may be confused with osteoblastic metastases, renal bone disease and other sclerosing bone disorders. As routine blood tests and isotope bone scans are normal in osteomesopyknosis, differentiation is readily achieved.