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Thomas Pfammatter

Publications and source records attributed to Thomas Pfammatter.

26 records · Page 2Linked to original sources
PubMed2003

Aortoiliac and renal arteries: prospective intraindividual comparison of contrast-enhanced three-dimensional MR angiography and multi-detector row CT angiography.

PURPOSE: To compare contrast material-enhanced three-dimensional (3D) magnetic resonance (MR) angiography and multi-detector row computed tomographic (CT) angiography in the same patients for assessment of the aortoiliac and renal arteries, with digital subtraction angiography (DSA) as the standard of reference. MATERIALS AND METHODS: DSA, 3D MR angiography, and multi-detector row CT angiography were performed in 46 consecutive patients. A total of 769 arterial segments were analyzed for arterial stenosis by using a four-point grading system. Aneurysmal changes were noted. The time required for performing 3D reconstructions and image analysis of both MR and CT data sets was measured. Patient acceptance for each modality was assessed with a visual analogue scale. Statistical analysis of data was performed. RESULTS: Sensitivity of MR angiography for detection of hemodynamically significant arterial stenosis was 92% for reader 1 and 93% for reader 2, and specificity was 100% and 99%, respectively. Sensitivity of CT angiography was 91% for reader 1 and 92% for reader 2, and specificity was 99% and 99%, respectively. Differences between the two modalities were not significant. Interobserver and intermodality agreement was excellent (kappa = 0.88-0.90). The time for performance of 3D reconstruction and image analysis of CT data sets was significantly longer than that for MR data sets (P <.001). Patient acceptance was best for CT angiography (P =.016). CONCLUSION: There is no statistically significant difference between 3D MR angiography and multi-detector row CT angiography in the detection of hemodynamically significant arterial stenosis of the aortoiliac and renal arteries.

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PubMed2003

Evaluation of aortoiliac aneurysm before endovascular repair: comparison of contrast-enhanced magnetic resonance angiography with multidetector row computed tomographic angiography with an automated analysis software tool.

PURPOSE: The purpose of this study was to assess accuracy and reliability of a volumetric analysis of abdominal aneurysms on the basis of multidetector row computed tomographic angiography (CTA) and magnetic resonance angiography (MRA) with a commercially available automated vessel analysis software program. MATERIALS AND METHODS: Twenty patients with abdominal aortic aneurysms underwent preoperative CTA and MRA before endovascular repair. Postdeployment CTA was performed in 15 of these 20 patients (75%). All preoperative CTA and MRA and postdeployment CTA data sets were analyzed with an automated software tool. The length of the stent grafts on postdeployment CTA was measured and compared with the true length of the primary component. Two readers independently evaluated 13 vessel parameters on preoperative CTA and MRA, which are considered to be important in planning stent graft deployment. RESULTS: With the automated analysis software tool, all measurements could be performed on either CTA or MRA data sets. There was no statistically significant difference between postdeployment measurements of stent graft length on CTA and the true dimensions of the implanted stent grafts. Interobserver agreement for all of the measurements with either CTA or MRA was good to excellent (interclass coefficient, 0.71 to 0.99) with only minimal mean differences of measured dimensions between both readers (range, -2.0 to +2.3 mm, Bland-Altman). Intermodality agreement between CTA and MRA was good to excellent (interclass coefficient, 0.62 to 0.98) with small mean differences of measured dimensions between both methods (range, -4.1 to +2.1 mm, Bland-Altman). CONCLUSION: Volumetric measurement with an automated analysis software tool allows a fast, precise, and reliable noninvasive preoperative determination of all aortic dimensions on the basis of either CTA or MRA data sets.

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PubMed2002

Laser-induced thermotherapy of the vertebral body: preliminary assessment of safety and real-time magnetic resonance monitoring in an animal model.

RATIONALE AND OBJECTIVES: To evaluate the safety of percutaneous laser-induced thermotherapy (LITT) of vertebral bodies and the feasibility of monitoring the thermal effects with real-time magnetic resonance (MR) imaging. MATERIALS AND METHODS: Laser fibers were placed in nine vertebral bodies of two minipigs under CT-guidance. LITT was performed in an open 0.5 T MR scanner using an Nd: YAG laser source. A T1-weighted MR sequence was used for continuous color-coded temperature monitoring. Histology of the vertebral body and spinal cord were subsequently obtained. RESULTS: Thermal lesions of the vertebral bodies measured 8 to 11 mm (mean 9.3 mm) in diameter. Thermal injuries of the spinal cord were observed in all four levels in which cortical bone surrounding the spinal canal was damaged during needle placement and in none with intact cortical bone. MR monitoring of the thermal effect was possible only if acquired in breath-hold technique. CONCLUSIONS: An intact cortical bone seems to be a prerequisite for safe LITT of the vertebral body. Real-time MR-monitoring of the thermal effect in vertebral bodies and the spinal canal was feasible with breath-hold acquisition. Larger studies are necessary to further evaluate accuracy of real-time MR imaging.

Animals↗
PubMed2002

Short-term results of endovascular AAA repair with the Excluder bifurcated stent-graft.

PURPOSE: To evaluate the safety and efficacy of endovascular abdominal aortic aneurysm (AAA) repair with a commercial modular stent-graft. METHODS: Between February 1998 and May 2000, 66 consecutive patients (56 men; mean age 70 years, range 51-87) were recruited for a single-center study to examine the safety and efficacy of the Excluder stent-graft for endovascular AAA repair. The patients were predominantly asymptomatic (2 symptomatic) and categorized as ASA III or IV (62, 94%), with aneurysms that ranged from 35 to 89 mm in diameter (mean 56). Surveillance included clinical examination and computed tomographic aortography at discharge, 6 weeks, and at 6, 12, and 24 months. RESULTS: All endoprostheses were implanted as intended, but 1 patient succumbed to an intraprocedural brainstem infarction (1.5% 30-day mortality rate). The major and minor morbidity rates were 21% and 4.5%, respectively. Primary technical success at discharge was 68% (45/66), largely as the result of a 30% (20/66) endoleak rate. The aneurysm exclusion rate at 30 days was 88%. During the mean 5.8-month follow-up, no device migration, limb kinking, aneurysm rupture, or limb thrombosis was observed. CONCLUSIONS: Endoluminal AAA repair with the bifurcated Excluder stent-graft is safe and efficacious in the short term. Longer surveillance will have to demonstrate if the excellent early results can be maintained over the years.

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PubMed2002

Multidetector CT: detection of active hemorrhage in patients with blunt abdominal trauma.

OBJECTIVE: The aim of this study was to determine the imaging findings and the prevalence of active hemorrhage on contrast-enhanced multidetector CT in patients with blunt abdominal trauma. MATERIALS AND METHODS: Contrast-enhanced multidetector CT images of 165 patients with blunt abdominal trauma were reviewed for the presence of extravasated contrast agent, a finding that represents active hemorrhage. The site and appearance of the hemorrhage were noted on multidetector CT images. These findings were compared with surgical and angiographic results or with clinical follow-up. RESULTS: On multidetector CT images, active hemorrhage was detected in 22 (13%) of 165 patients with a total of 24 bleeding sites (14 intraperitoneal sites and 10 extraperitoneal sites). Active hemorrhage was visible most frequently as a jet of extravasated contrast agent (10/24 bleeding sites [42%]). Diffuse or focal extravasation was less frequently seen (nine [37%] and five [21%] bleeding sites, respectively). CT attenuation values measured in the aorta (mean, 199 H) were significantly higher than those measured in extravasated contrast material (mean, 155 H) (p < 0.001). Sixteen (73%) of 22 patients with active bleeding on multidetector CT images underwent immediate surgical or angiographic intervention. One patient received angiographic therapy 10 hr after undergoing multidetector CT, and five patients died between 1 and 3 hr after multidetector CT examination. CONCLUSION: Active hemorrhage in patients after blunt abdominal trauma is most frequently visible as a jet of extravasated contrast agent on multidetector CT. When extravasation is detected, immediate surgical or angiographic therapy is required.

Abdominal Injuries↗
PubMedDate not supplied

Endovascular therapeutic options for isolated iliac aneurysms with a working classification.

The purpose of this paper is to demonstrate a variety of stent-grafting and embolization techniques and describe a new classification for endovascular treatment of isolated iliac artery aneurysms. A total of 19 patients were treated for isolated iliac aneurysms. Depending on the proximal iliac neck and the uni-/bilaterality of common iliac artery aneurysms (CIAA's) the patient may be treated by a tube (Type Ia) or a bifurcated stent-graft (Type Ib) in addition to internal iliac artery embolization. Neck anatomy is also critical in determining therapeutical options for internal iliac artery aneurysms (IIAA's). These are tube stent-grafting plus internal iliac branch embolization (Type IIa), coiling of afferent and efferent internal iliac vessels (Type IIb) and IIAA packing (Type IIc). The average length of stay for these procedures was 3.8 days. During the mean follow-up of 20.9 months, aneurysm size remained unchanged in all but 4 patients. Reinterventions were necessary in option Type Ib (3/8 pat.) and Type Ia (1/7 pat.) due to extender stent-graft migration (n = 2) or reperfusion leaks (n = 2). We conclude that Iliac artery aneurysms may be successfully and safely treated by a tailored approach using embolization or a combination of embolization and stent-grafting. Long-term CT imaging follow-up is necessary, particularly in patients treated with bifurcated stent-grafts (Type Ib).

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PubMedDate not supplied

Transvenous biopsy of cavo-atrial tumors with the Quick-Core needle.

A variant application of the renal Quick-Core needle in 3 patients with cavo-atrial tumors is reported. In all 3 patients either a transjugular or transfemoral venous biopsy approach with this device yielded sufficient tissue for histological diagnosis at the first attempt. Bioptic diagnoses were confirmed either by surgery or radiological and clinical response to a specific chemotherapy. There were no procedure-related complications.

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