PubMed Health⌕ Search

Biomedical subjects

Derek A Gould

Publications and source records attributed to Derek A Gould.

10 recordsLinked to original sources
PubMed2006

Metrics for an interventional radiology curriculum: a case for standardisation?

Interventional radiology training and assessment would benefit greatly from the introduction of simulation. Assessment methods should facilitate the highest standards of training and therefore must be chosen on the basis of evidence of impact on learning. A study of assessment in a training model shows the need for specialty specific metrics which were derived from a task analysis of interventional procedures.

Computer Simulation↗
PubMed2005

In vivo force during arterial interventional radiology needle puncture procedures.

To adequately simulate the forces generated during interventional radiological (IR) procedures, non intrusive in-vivo methods must be used. Using finger tip mounted, non intrusive capacitance force sensor pads (PPS, Los Angeles, California) we have been able to measure the forces involved in interventional radiology without a change in procedure technique. Data acquired during the process of calibration of the capacitance pads in conjunction with extensive in-vitro needle puncture force measurement using a commercially available tensile tester (Nene Industries, UK) are presented here.

Computer Simulation↗
PubMed2003

Transluminal occlusion of a pseudoaneurysm arising from a thoracic aortic graft patch using catheter delivery of thrombin.

A 39-year-old man with Marfan syndrome underwent replacement of the aortic valve, root, and ascending aorta for acute type A dissection. Subsequently, he underwent infrarenal aortic replacement for aortic rupture and then graft repair of a thoracoabdominal aneurysm with patch-bearing intercostals. After the third procedure, massive intraperitoneal hemorrhage required three subsequent laparotomies. CT scan showed two thoracic aortic pseudoaneurysms at the patch-graft junction that were sequentially embolized with transcatheter delivery of thrombin.

Adult↗
PubMed2003

Migration versus apparent migration: importance of errors due to positioning variation in plain radiographic follow-up of aortic stent-grafts.

PURPOSE: To demonstrate the influence of radiographic positioning on the assessment of stent-graft migration using plain radiographs following endovascular abdominal aortic aneurysm repair. METHODS: Equations were derived to correct for artifactual stent-graft migration introduced by geometric distortion due to variations in positioning between radiographs acquired at different times. A phantom system was used to validate the equations. RESULTS: Errors in stent position increase with (1) the distance of the aortic stent-graft from the midline and (2) differences in radiographic centering points in the craniocaudal direction; other variables have little effect. For typical stent positions, errors are small if the centering changes by <8 cm. Consistent radiographic positioning to within 4 cm on successive imaging studies limits errors to 1.5 mm. Even if artifactual migration is large, the true migration can be reliably calculated to within 2 mm. CONCLUSIONS: Artifactual migration due to variation in radiographic centering is not usually clinically significant if care is taken to center radiographs consistently. Radiographs in which artifactual migration may be important are readily identified, and mathematical correction is straightforward.

Aortic Aneurysm, Abdominal↗
PubMed2002

Diagnosis of an intracranial arteriovenous malformation using extracranial carotid Doppler sonography.

Carotid sonography is a well-established technique in the evaluation of patients with neurologic symptoms. We describe the case of a woman in whom duplex Doppler sonography of the extracranial carotid circulation showed high-velocity diastolic flow and a low resistance index without turbulence or morphologic abnormality of the artery. A suspected cause of this finding was low-resistance distal circulation secondary to low-resistance intracranial circulation due to an arteriovenous malformation. This diagnosis was later confirmed by CT. Because of the significant risk of bleeding associated with an asymptomatic intracranial arteriovenous malformation, duplex Doppler sonographic findings suggesting a low-resistance waveform in the presence of a morphologically normal carotid artery should prompt further imaging.

Adult↗
PubMed2002

Aneurysm neck diameter after endovascular repair of abdominal aortic aneurysms.

PURPOSE: To determine aneurysm neck diameter change after endovascular repair (EVR) of abdominal aortic aneurysm (AAA) and its relationship to stent-graft diameter. MATERIALS AND METHODS: The cases of 73 patients with AAAs who underwent EVR were reviewed retrospectively: 68 had preoperative imaging available. Neck diameter was reviewed by a single observer (M.F.B.) on preoperative, immediate postoperative, annual, and most recent contrast-enhanced computed tomographic scans. Baseline and follow-up neck diameters were compared with the manufacturers' values for unconstrained stent-graft diameters. RESULTS: Intraobserver error was 2 mm. Aneurysm neck diameter increased from 21.8 mm (range, 17-28 mm) at baseline to 22.8 mm (range, 19-30 mm) postoperatively and 25.8 mm (range, 19-31 mm; P <.001) at a mean follow-up of 25.5 months (range, 6.2-60.8 mo). Neck diameter increase was more than 2 mm in 24 patients (33%). Mean change in the first, second, third, and fourth years was +1.63 mm, +0.52 mm, +0.25 mm, and +0.33 mm, respectively. Baseline mean stent-graft oversizing was 2.9 mm (13.7%; range, -1 to +8 mm), which decreased to 0.7 mm (range, -4 to +6 mm) at latest follow-up. Neck diameter exceeded stent-graft diameter (mean, 1.8 mm; range, 1-4 mm) in 21 cases (28%) and by more than 2 mm in five cases (6.8%). When neck diameter change was correlated with change in sac diameter, it was found to be insignificant (P =.24); however, it was significantly correlated with baseline oversizing (P =.01). CONCLUSIONS: After EVR, the aneurysm neck dilates, mostly in the first 2 years, by greater than 2 mm in one third of patients. This is possibly related to the presence of the endograft. The associated reduction of stent-graft oversizing warrants continued vigilance for proximal endoleak.

Aged↗
PubMed2002

Detection of endoleak with enhanced ultrasound imaging: comparison with biphasic computed tomography.

PURPOSE: To compare unenhanced and enhanced ultrasound imaging to biphasic computed tomography (CT) in the detection of endoleak after endovascular abdominal aortic aneurysm (AAA) repair. METHODS: Fifty-three patients (44 men; mean age 70 years) were examined during 96 follow-up visits after endovascular AAA repair. All patients had color Doppler and power Doppler ultrasound studies performed before and after the administration of an ultrasound contrast agent. Biphasic (arterial and delayed) CT was performed on the same day, and the ultrasound and CT studies were independently scored to record the presence or absence of endoleak and the level of confidence in the observation. RESULTS: The sensitivity of the ultrasound techniques to detect endoleak improved with the use of ultrasound contrast media, ranging from a low of 12% with unenhanced color Doppler to 50% with enhanced power Doppler. However, the enhanced power Doppler failed to detect 9 type II endoleaks identified by CT (86% negative predictive value for endoleak). There were only 2 graft-related endoleaks in the study; one was diagnosed from the ultrasound image, but the other had nondiagnostic ultrasound scans because of poor views. CONCLUSIONS: Ultrasound scanning with or without contrast enhancement was not as reliable as CT in diagnosing type II endoleak. CT imaging remains our surveillance modality of choice.

Aged↗