Biomedical subjects
M A Jeffree
Publications and source records attributed to M A Jeffree.
Traumatic basilar pseudoaneurysm with a basilar-cavernous arteriovenous fistula.
A traumatic pseudoaneurysm of the basilar artery with a basilar-cavernous sinus arteriovenous fistula was diagnosed in a 12-year-old girl using CT, MRI and angiography. It was successfully treated by coil embolisation. We speculate on the mode of formation of this rare traumatic lesion.
Intrapituitary fluid levels following haemorrhage: MRI appearances in 13 cases.
Demonstration of fluid levels on MRI is well recognised in cerebral haematomas, tumours and cysts. The occurrence of fluid levels within haemorrhagic pituitary tumours has not previously been described in detail. Evidence of haemorrhage was identified in 27 of 125 pituitary tumours. Fluid levels occurred in 13 of these haemorrhagic tumours. No association with histological type was identified. Recognised risk factors for haemorrhage were identified in half of the cases.
Tentorial dural arteriovenous fistulae: endovascular treatment with transvenous coil embolisation.
Tentorial arteriovenous dural fistulae are uncommon. They are aggressive lesions: of all intracranial dural fistulae they are the most likely to present with haemorrhage. Treatment options include surgical excision or interruption of leptomeningeal draining veins and arterial embolisation in isolation or in combination with surgery. There has been one case report of treatment by percutaneous transvenous coil embolisation. We describe successful transvenous coil embolisation of two tentorial dural fistulae presenting with subarachnoid haemorrhage.
The porous, guidewire-directed, detachable aneurysm liner: a new concept in the endovascular treatment of intracranial aneurysms.
A new device for the endovascular treatment of aneurysms is described. It consists of a guidewire-directed porous liner or bag, detachably mounted on a microcatheter and designed to be inserted into an aneurysm and to be filled with detachable coils or other embolic agents. Several prototypes have been made. Preliminary in vitro and in vivo experiments have demonstrated its behavior in relatively wide-necked aneurysms.
MRI of an abscess of the cervical spinal cord in a case of Listeria meningoencephalomyelitis.
A case of Listeria meningoencephalomyelitis is described and the MRI appearances of an abscess of the cervical spinal cord are presented. The MRI appearances did not allow a definitive diagnosis before death.
Metastatic bronchial adenocarcinoma showing the "meningeal sign": case note.
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Calvarial thinning in low grade intracerebral gliomas presenting with epilepsy.
Intracranial gliomas can erode or thin the skull. These changes are detectable on conventional radiographs but they appear to be rare. Only a few examples of the appearances on computed tomography (CT) are recorded in the literature. This paper describes the CT appearances of 11 cases. All of the patients presented with epilepsy. In most the tumours were small and indolent. Some went undetected or misdiagnosed for several years because of a lack of familiarity with the appearances.
Computed tomography in suspected tarsal coalition. Examination of 26 cases.
Coronal plane computed tomography (CT) was performed in 26 consecutive patients with clinical suspicion of tarsal coalition. Twenty patients had plain CT and 6 had CT talocalcaneonavicular arthrography. Fifteen patients were found to have coalition. Of these 15 patients, 12 had talocalcaneal coalition (9 bilateral, 3 unilateral), 2 patients had combined talocalcaneal and calcaneonavicular coalitions, and the remaining patient had bilateral calcaneonavicular coalitions. Surgical findings corroborated the CT diagnosis in 9 patients with talocalcaneal coalition and in 2 patients with calcaneonavicular coalition. Ossified talocalcaneal coalitions were found in children aged 6 and 10 years, i.e., well below the conventionally stated age range of 12 to 16 years. CT is the investigation of choice in suspected tarsal coalition if plain radiography is not diagnostic. CT arthrography did not generally provide further information, but may be useful if plain CT is equivocal.
Indolent glioma: a cause of epilepsy.
We studied eight patients with indolent gliomas. In all eight cases, despite characteristic radiological features, there was a delay in diagnosis because of misinterpretation of the initial computed tomogram. These tumours are an important cause of epilepsy of childhood, and surgery may well alleviate the epilepsy and possibly achieve a long term 'cure'. Therefore it is important that a diagnosis is made early and the lesion completely excised.
Multiple ileal carcinoid tumours.
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Endoscopic diagnosis of a bleeding ileal carcinoid tumour.
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Re: Detailed per-oral small-bowel examination versus enteroclysis.
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A simple method for limiting angioplasty catheter balloon pressures.
Percutaneous angioplasty catheter balloons may rupture if over-inflated. Balloon inflation pressures are not always measured. We describe a simple and inexpensive method for limiting balloon inflation pressures, using no additional equipment.
Primary carcinoid tumours of the ileum: the radiological appearances.
Primary carcinoid tumours are rarely detected in the small intestine by conventional radiological methods. The radiological features are presented of 11 patients with primary small-intestinal carcinoids, in whom the tumour was demonstrated by the barium infusion technique. In four of these patients the site of the primary tumour was also demonstrated angiographically. We have found these methods valuable in identifying primary carcinoid tumours and consider them to be the investigations of choice in evaluating patients with suspected or established carcinoid syndrome.
Initial in vitro evaluation of a pediatric vortex-mixing membrane lung.
A new design for a pediatric membrane lung is described in this paper. The lung consists of eight blood compartments, each having six U-shaped blood channels, with microporous PTFE membranes supported on rigid plates in such a way that the membranes form furrowed blood channels. Two rolling diaphragm pumps are attached to the open ends of the U-shaped blood channels; these pumps are operated in antiphase. Mean flow is provided by a roller pump placed at the inlet end of the membrane lung. Pulsatile blood flow within the blood channels produces successive vortex formation and ejection, leading to good blood mixing and high efficiency in gas transport. The design of the rolling diaphragm piston pumps ensures that the blood prime volume is low (280 ml), and the grouping of the pumps at one end of the oxygenator allows the driving mechanism to be simple and compact. The relatively wide blood channels (minimum width 0.5 mm) and vortex mixing make priming the membrane lung particularly easy. The membrane area is 0.39 m2. Preliminary performance testing of the pediatric membrane lung was undertaken by pumping blood around a circuit containing a roller pump, the membrane lung, and a bubble oxygenator (to adjust the blood gases at the inlet to the membrane lung). In five such experiments it was shown that the membrane lung transferred 80 ml O2/min and 120 ml CO2/min at a blood flow rate of 1.5 L/min.
Gel layer limited haemofiltration rates can be increased by vortex mixing.
Haemofiltration has been used since 1976 as an alternative to haemodialysis in the treatment of chronic renal failure (1). Ultrafiltration flow rates (UFR) from blood are slow and it has been observed that when blood or plasma is ultrafiltered using highly permeable membranes, the UFR reaches a maximum which is independent of trans-membrane pressure (delta Pm) (2). We have confirmed this result during steady flow through an ultrafilter employing polyacrylonitrile membrane (Rhône Poulenc AN 69) but have also shown that this maximum can be exceeded by a factor of eight in the same device when vortex mixing is induced by pulsing the blood flow over furrowed channels.
A practical secondary-flow hemodialyzer.
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