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Biomedical subjects

K R Thomson

Publications and source records attributed to K R Thomson.

At least 19 recordsLinked to original sources
PubMed1998

Dynamic gadolinium DTPA-enhanced magnetic resonance of intravascular stents.

RATIONALE AND OBJECTIVES: Magnetic resonance contrast enhancement depends on the timing of image acquisition. Human trials have demonstrated efficacy of renal artery stents on salvage of renal function. This study assessed the ability of dynamic gadolinium (Gd)-DTPA administration to demonstrate renal and iliac artery stent patency compared to conventional angiography as the gold standard. METHODS: Seven subjects with eight stents referred for angiography underwent dynamic magnetic resonance studies, all with renal artery stenting. All were examined with conventional angiography and after dynamic Gd-DTPA infusion. Coronal magnetic resonance images were acquired using a GE Signa 1.5 T magnet (fast spoiled gradient echo; echo time = 4.2 ms; repetition time = 68-150 ms; flip angle = 75 degrees) 0 to 600 seconds after 0.1 mmol/Kg Gd-DTPA intravenous bolus injection during sequential breath-hold acquisitions 13 to 32 seconds each. RESULTS: All eight stents were visualized with 100% accurate patency documentation. CONCLUSIONS: Fast spoiled gradient echo magnetic resonance imaging with bolus Gd-DTPA administration can provide adequate time and spatial resolution to demonstrate arterial stent patency.

Aged↗
PubMed1998

Detection of renal arteries with fast spin-echo magnetic resonance imaging.

With the increasing use of non-invasive imaging with MR and volumetric CT to evaluate renal arteries, the ability to accurately detect the number and state of native renal arteries becomes critical if conventional angiography is to be supplanted in these settings. The present study evaluated the utility of a fast spin-echo (FSE) T2-weighted sequence to detect the number and course of renal arteries and their ostia compared to conventional angiography. Ten patients underwent conventional catheter angiography either for renal artery stenosis evaluation or as potential renal donors. Each patient then had an MR study of the renal arteries and kidneys with FSE MR (TR = 4000 ms, TE = 102 ms, eight-echo train length, 5-mm-thick interleaved 128 phase encodes, superior and inferior saturation pulses, number of excitations (NEX) = 4, on a 1.5-T superconducting magnet (GE, Milwaukee, WI, USA). Images were reviewed by two 'blinded' radiologists and renal arteries were counted and their ostia were evaluated. Results were compared with angiography and inter- and intra-observer statistics were calculated. All 10 patients underwent MR successfully, nine for renal artery stenosis (RAS) evaluation and one was a renal donor. A total of 24 renal arteries were imaged in 19 kidneys. Fast spin-echo MR is 95% accurate (95% CI: 88-100%) in detection of renal arteries, with no statistical difference between FSE MR and catheter angiography (McNemar P = 0.0). Inter- and intra-observer statistics demonstrate good-to-excellent agreement in renal artery detection (kappa: 0.63-0.90). In one case of RAS evaluation an incidental adrenal mass was detected as the aetiology of the patient's hypertension. Fast spin-echo MR can be a useful adjunct as part of the imaging for renal arteries with MRI.

Female↗
PubMed1998

Stenting in malignant and benign vena caval obstruction.

Expandable metallic stents have been used with considerable success for the palliation of malignant vena caval obstruction. The role of stenting in vena caval obstruction of benign aetiology is less well defined. A review of 11 patients stented for vena caval obstruction and a review of recent series in the literature is presented. Of the 11 patients, seven patients had involvement of the superior vena cava (SVC), and four patients had inferior vena caval (IVC) obstruction. Seven cases had malignant vena caval obstruction, with a benign aetiology (SVC n = 3; IVC n = 1) in the other four cases. All seven patients treated with SVC stents experienced complete resolution or significant improvement in symptoms with no recurrence over the duration of available follow-up, over an average of 4.3 months (range: 1 week-12 months). Only one of four IVC lesions stented resulted in a good clinical response. All four patients with vena caval obstruction of benign aetiology had a good outcome. One patient experienced a small pulmonary embolus following SVC stent insertion without further sequelae. No other serious complications were encountered. Stenting can provide prompt relief of vena caval obstruction with low morbidity, and high patency rates in both benign and malignant vena caval lesions.

Adult↗
PubMed1997

Interventional radiology.

One of the most interesting things about interventional radiology is how techniques have been borrowed from other areas. The lateral thinking which characterises this new specialty has allowed it to flourish even while it has lost "turf" to other specialties. Inevitably, primary referral to interventional radiologists will happen in the same way as referral to, say, surgeons or cardiologists dose already. Those who administer health funds and medical education will need to adjust to this new situation. This article provides examples of many treatment tasks that the interventional radiologist now tackles.

Angioplasty↗
PubMed1995

Thrombolytic therapy for basilar artery thrombosis in the puerperium.

A case is presented of a woman in whom basilar artery thrombosis developed 14 days post partum. She was successfully treated with intraarterial urokinase. This case demonstrates that complete neurologic recovery can be achieved after recanalization of the basilar artery with thrombolytic therapy.

Angiography↗
PubMed1995

Stent placement in coeliac and superior mesenteric arteries to restore vascular perfusion following aortic dissection.

The main trunks of both coeliac and superior mesenteric arteries were sheared off the abdominal aorta by an anterior dissection that spared the renal arteries. Both vessels were cannulated and a Walstent inserted across the false lumen to restore normal coeliac and superior mesenteric perfusion. This produced a successful haemodynamic and angiographic result with improvement in the patient's clinical condition.

Aged↗
PubMed1995

Analgesia and sedation in interventional radiological procedures.

The use of intravenous analgesia and anxiolytics in interventional radiology improves the patient's tolerance of potentially painful and prolonged procedures and allows the radiologist better control of the course of the procedure being undertaken. Monitoring of the patient's oxygen saturation, pulse rate, respiration, blood pressure and cardiac rhythm during a procedure is essential. Fentanyl and midazolam is a combination that is effective and convenient to use because both agents are relatively short acting, have little cardiovascular depression and are easily reversible (with naloxone and flumazenil). They are a better alternative to pethidine and diazepam because they can be more tightly titrated and controlled and are safer and more suitable for use in outpatients. Monitoring for respiratory depression is important and special care must be taken in the elderly and patients with hepatic, renal or chronic airways disease. General anaesthesia may be unavoidable in patients who are unstable, unco-operative or who have raised intracranial pressure.

Aged↗
PubMed1995

Post-cholecystectomy haemobilia: enjoying a renaissance in the laparoscopic era?

Trauma to the right hepatic artery during biliary surgery can lead to false aneurysm formation. Subsequent rupture into the biliary system, which may occur after a considerable delay, will then result in major haemobilia. This report details five cases referred to the Royal Melbourne Hospital over a 12 month period, four of which followed initial laparoscopic procedures, and emphasizes important management procedures to prevent and treat this previously rare complication.

Aged↗
PubMed1995

Cerebral venography and manometry in idiopathic intracranial hypertension.

Cerebral venography and manometry in nine patients with idiopathic intracranial hypertension consistently showed venous hypertension in the superior sagittal sinus and proximal transverse sinuses, with a significant drop in venous pressure at the level of the lateral third of the transverse sinus. The abnormality, clearly demonstrated by manometry, was not well shown on the venous phase of cerebral angiography. The appearance of the transverse sinus on venography varied from smooth tapered narrowing to discrete intraluminal filling defects that resembled mural thrombi. Two patients with intracranial hypertension due to minocycline did not show venous hypertension.

Adolescent↗
PubMed1994

Bacteriological studies of open versus closed contrast medium delivery systems in angiography.

The aim of this study was to evaluate the safety of the 'open' method of contrast medium delivery in the angiographic theatre, in which contrast medium is decanted into open galley pots on sterile trolleys. The air bacterial load within the angiographic theatre was sampled before and during angiographic procedures. The relationship of staff and patient activity to bacterial load was assessed. Samples of Iopromide (Ultravist 370; Schering Pty Ltd, Sydney, NSW, Australia) decanted into galley pots were taken for bacterial culture at the end of seven patient procedures. Air bacterial loads were comparable with operating theatre levels and were heaviest during staff activity. Three of seven samples taken at the end of angiographic procedures from air-exposed galley pots yielded contaminants, but the number of bacteria was below that required to produce septicaemia under normal conditions. These results suggest that the open system of contrast medium delivery can be safely used, providing that bacterial checks of room contamination are performed and personnel entry into the theatre is strictly limited.

Air Microbiology↗
PubMed1994

Multiple doses of contrast medium from a single container: bacteriological studies.

Preparations of Iopromide (Ultravist 370; Schering Pty Ltd, Sydney, NSW, Australia), brain/heart infusion broth (BHI; positive growth control) and distilled water (negative control) were inoculated with 10(3) to 10(4) Pseudomonas aeruginosa, Escherichia coli or Staphylococcus aureus cells and incubated at 37 degrees C. Slow decreases (up to one log) were observed in each organism's count in Iopromide and distilled water at room temperature and in S. aureus and E. coli in Iopromide and distilled water at 35 degrees C until 6-8 h, when counts stabilized. BHI cultures showed logarithmic increases. P. aeruginosa counts increased (half log over 8 h) in Ultravist at 37 degrees C. Radiology laboratories were shown to have similar airborne bacterial loads to operating theatres. Samples from repeatedly entered Iopromide bottles showed no contamination. Multiple intravenous doses from a single bottle of non-ionic contrast medium can safely be used as a cost-saving measure provided scrupulous attention is paid to aseptic preparation. Unused decanted contrast medium should be discarded after 4 h.

Bacteria↗
PubMed1994

Transjugular intrahepatic portal-systemic shunts (TIPS)--initial experience and clinical outcome.

BACKGROUND: The clinical role of the transjugular intrahepatic portal-systemic shunt (TIPS) has not been fully defined. AIMS: To determine the technical results of TIPS and the clinical outcome of patients undergoing the procedure. METHODS: Retrospective audit of the results of the first 31 procedures performed in Melbourne. RESULTS: Thirty procedures were performed for variceal haemorrhage, one procedure was for ascites. The aetiology of the liver disease was cirrhosis due to alcohol in 20, cryptogenic in five, chronic viral infection in four, and autoimmune chronic active hepatitis in one. Nodular regenerative hyperplasia was present in one patient. Seventy-seven per cent of procedures were considered successful based on the angiographic demonstration of shunt patency at the end of the procedure. The in-hospital mortality in all patients undergoing TIPS was 45% and was 42% in patients undergoing technically successful TIPS. Only age could be identified as predictive of death in hospital. In patients leaving hospital, we found a rebleeding rate of 57% with one patient dying of bleeding, one requiring balloon tamponade and two requiring variceal sclerotherapy. Hepatic trauma was documented in six cases, shunt thrombosis in four cases, stent displacement in two cases and severe hepatic encephalopathy in one case. CONCLUSIONS: TIPS has the potential to decompress the portal venous system, but the procedure is technically complex and should be performed in the knowledge that mortality and morbidity can be relatively high, particularly in patients whose condition is poor.

Adult↗
PubMed1993

Superselective catheterisation with the "Explorer" catheter.

An Australian-manufactured, superselective catheter is available for deep catheterisation of target vessels using a coaxial technique. The catheter is compatible with standard micro coils and is able to deliver embolic particles of appropriate size.

Catheterization↗
PubMed1989

Acute dissection of the aorta: which test?

With the recent advent of computerized tomography (CT) and magnetic resonance imaging, the clinician is now faced with a variety of tests for the investigation of suspected acute aortic dissection. Forty-two patients were referred to the Department of Radiology over a 4.5-year period for the investigation of suspected dissection; 20 were diagnosed as having the condition. From the results of the evolving experience, it is believed that all patients suspected of having this disease should be studied with a three level dynamic CT in the first instance because the presence or absence of dissection and the type of dissection (type A or type B) can be determined with confidence.

Acute Disease↗