PubMed Health⌕ Search

Biomedical subjects

R Tomczak

Publications and source records attributed to R Tomczak.

At least 19 recordsLinked to original sources
PubMed2001

Endograft treatment of anastomotic aneurysms following conventional open surgery for infrarenal aortic aneurysms.

OBJECTIVE: to evaluate the use of endograft therapy for treating anastomotic aneurysm following open surgical repair of infrarenal aneurysms of the abdominal aorta. METHODS: four male patients (age 47-75 years) at high surgical risk (ASA IV n=3, ASA III n=1) developed secondary aneurysms at the site of the central (four aneurysms) and additional peripheral (two aneurysms) anastomosis of their tube or bifurcation prosthesis an average of 13 years (range 1-23 years) after conventional open surgical correction of infrarenal aneurysm of the abdominal aorta. In two patients, there was covered rupture of the aneurysm sac. The aneurysm diameter was 4.8 cm, 8.0 cm, 7.4 cm, 7.0 cm, respectively (mean 6.8 cm). Follow-up included helical CT imaging at 1 week, 3 months and 6 months postoperatively. RESULTS: anastomotic aneurysm was successfully treated in all four cases. No evidence of endoleak was observed during the follow-up period. Two patients died 14 and 18 days after surgery due to myocardial infarction and cerebrovascular accident. The endovascular repair of the two patients who died was intact. CONCLUSION: although no long-term results are available, the use of a graft-in-graft method to repair anastomotic aneurysms following conventional implantation of tube or bifurcation prostheses appears to be effective, particularly in patients at high surgical risk.

Aged↗
PubMed2001

Multimodal cranial neuronavigation: direct integration of functional magnetic resonance imaging and positron emission tomography data: technical note.

OBJECTIVE: This is the first report of the direct integration of functional magnetic resonance imaging (fMRI) and positron emission tomography (PET) data into cranial neuronavigation. METHODS: In a patient with a left precentral oligodendroglioma (World Health Organization Grade III), the Zeiss MKM system (Carl Zeiss Co., Oberkochen, Germany) was used for navigation based on thin-slice, T1-weighted, contrast-enhanced magnetic resonance imaging (MRI) scans. fMRI and methionine PET data were integrated by landmark matching, with reference to skin fiducials. RESULTS: The inaccuracy of the image fusion between fMRI and T1-weighted MRI data was 1.7 mm, that between PET and T1-weighted MRI data was 4.3 mm, and that for the subsequent registration of the navigation was 1.2 mm. The correct fMRI localization of the precentral gyrus was intraoperatively verified by cortical somatosensory evoked potential (phase-reversal) monitoring. Although the tumor was not clearly defined in the MRI scans, [11C]methionine PET demonstrated a clear tumor border, enabling us to achieve gross total tumor removal without postoperative functional deficits. CONCLUSION: Functional neuronavigation permits observation and preservation of relevant brain areas. Other functional areas (such as short-term memory areas) that can be detected only by fMRI might also warrant future monitoring. The simultaneous integration of fMRI and PET data adds a new dimension to cranial neuronavigation, enabling the observation of tumors in relation to functional cortical areas (in our case, the motor strip).

Brain↗
PubMed2001

Percutaneous techniques for managing maldeployed or migrated stents.

PURPOSE: To report our experience in the percutaneous management of dislocated endovascular stents. METHODS: During a 6-year period, 28 (2.7%) patients with a maldeployed or migrated endovascular stent (20 Palmaz, 5 Wallstent, 2 Memotherm, and 1 AVE) were recognized among 1021 patients undergoing noncardiac vascular stent procedures. Percutaneous stent management was performed using balloon catheters, gooseneck snares, grasping forceps, or additional stent implantation on the basis of the stent type, degree of expansion, mechanical characteristics, and location of the stent. RESULTS: Three stents that embolized into the pulmonary artery were left in situ, but percutaneous management was successful in 23 (92%) of the remaining 25 dislocated stents (12 venous and 13 arterial stents). Twelve stents were repositioned in an alternate, stable position or the primarily intended location; 4 stents were anchored by a second stent, and 7 stents were removed percutaneously. In the 2 failed cases, the stents were retrieved using a minor surgical procedure. There were 2 minor groin hematomas but no secondary complications during a median follow-up of 26.2 months (range 1-62). CONCLUSIONS: Percutaneous management of migrated or maldeployed endovascular stents is highly effective with few complications. On the basis of our findings, these techniques should be considered the therapy of choice.

Adult↗
PubMed2001

Thrombus formation in aortic endografts.

PURPOSE: To examine the incidence of intraprosthetic thrombotic deposits in aortic endografts. METHODS: Transfemoral implantation of tube or bifurcated stent-grafts was performed in 82 patients (75 men; average age 67.7 years, range 25-88) for treatment of aneurysms of the abdominal (n = 73) or thoracic (n = 9) aorta in a 3.5-year period. Patients underwent 3-phase helical computed tomographic (CT) examinations at 3-month intervals. The length and cross-sectional area of any thrombotic deposits were measured from axial and 3-dimensional CT images. RESULTS: Over a 12.1-month mean follow-up, intraluminal deposits of thrombotic material were observed in 19 (23.2%) patients, all with infrarenal endografts that were predominately of a bifurcated design. The first signs of thrombus formation occurred on average 7 months postoperatively (range 1 week to 20 months). In 16 patients, nonocclusive deposits of thrombotic material were seen in the aortic segment of the endograft; a graft limb was involved in 5 patients. Three graft limbs occluded owing to kinking; no thrombus was seen on CT scans taken prior to occlusion. In 3 cases the thrombotic deposits disappeared completely from the prosthesis lumen during follow-up. CONCLUSIONS: Based on this small experience, nearly 1 in 5 patients may experience some degree of intraluminal thrombus following endovascular treatment of aortic aneurysms. Whether the deposition of thrombus is influenced by the geometry of the aortic stent-graft or by flow conditions within the prosthetic lumen must be determined in future studies.

Adult↗
PubMed2001

Endovascular interventions on persistent sciatic arteries.

PURPOSE: To report our experience with interventional procedures used to treat complete and incomplete persistent sciatic arteries (PSA). CASE REPORTS: Three female patients with PSAs displayed varying symptoms referable to this rare anatomical variant. In the first woman, a 1-year history of intermittent lower limb ischemia and an acute event prompted angiography, which demonstrated proximal occlusion of 2 crural vessels and a partially thrombosed sciatic artery aneurysm. To prevent further embolism, the aneurysm was excluded with a stent-graft. Endograft patency and aneurysm exclusion have been maintained up to 22 months. In a 41-year-old diabetic with chronic limb ischemia and digital gangrene, a flow-limiting stenosis of the sciatic artery was stented, restoring adequate pedal perfusion. The stent remained patent at the 18-month follow-up. The third patient suffered from a tumor-related pelvic hemorrhage originating from retrograde perfusion through the PSA, which had been ligated during previous surgery. Attempted embolization via a collateral connection between the incomplete PSA and the popliteal artery failed, and the patient died. CONCLUSIONS: Vasculopathies involving the sciatic artery are uncommon but may be amenable to interventional techniques, such as coil embolization and stent implantation. PSA aneurysm exclusion with a stent-graft may represent a new therapeutic alternative to standard surgery that obviates potential sciatic nerve damage, but the durability of the repair remains to be determined.

Adult↗
PubMed2001

Results of applying ADCON-L gel after lumbar discectomy: the German ADCON-L study.

OBJECT: Failed-back syndrome is still an unsolved problem. Use of ADCON-L gel, already commercially available, has been proven to reduce postoperative scarring in animal experiments. The authors of two controlled clinical studies have also shown positive results when applying the gel. They did not, however, establish patient-oriented endpoints. The authors report a study of ADCON-L in which they focus on patient-oriented endpoints. METHODS: Patients with lumbar disc herniation were randomized to an ADCON-L-treated or control group. Therapeutic success was evaluated using the validated Hannover Questionnaire on Activities of Daily Living (FFbH) 6 months after surgery. The study took place between November 14. 1996, and April 20, 1998, in eight neurosurgical centers in Germany. A total of 398 patients was recruited; 41 patients dropped out during follow up. The mean functional FFbH score (100 points = all activities are possible without problem; 0 points = no activity is possible) was 78.5 points in the ADCON-L-treated group compared with 80 points in the control group. Furthermore, in terms of secondary outcome variables, the ADCON-L group did not have an advantage over the control group. Only the mean magnetic resonance imaging score showed a slight advantage of ADCON-L over the control group. CONCLUSIONS: The authors found no positive effect of treatment with ADCON-L gel in patients in whom one-level lumbar microdiscectomy was performed. Because of its rather large sample size and its homogeneity, the study had sufficient power to detect even small differences between the two groups.

Activities of Daily Living↗
PubMed2000

In vivo imaging of activated microglia using [11C]PK11195 and positron emission tomography in patients after ischemic stroke.

Neuroprotective strategies are currently being developed for stroke patients. Although the focus is on the development of early treatment the importance of late pathogenetic events is increasingly recognized. To investigate the microglial reaction in stroke we used a marker for activated microglia, [11C]PK11195, and PET in five patients with ischemic stroke 5-53 days after infarction. In one patient serial measurements were made. We demonstrated in each individual and at each point in time that a microglial reaction takes place in the area where T1 weighted MRI (magnetic resonance imaging) shows intensity changes. We consider this PET method as a promising tool to study the late pathogenetic consequences of cerebral infarction and to evaluate neuroprotective strategies with respect to the consequences of the microglial activation.

Adult↗
PubMed2000

[Ischemia of the lower extremity due to a persistent a. ischiadica--a possible interventional therapeutic approach].

The sciatic artery is a rarely seen variant of the vessels of the lower limb. Anatomically it is the prolongation of the inferior gluteal artery and accompanies the sciatic nerve from the sciatic foramen to the knee. More than other vessels, the sciatic artery shows vasculopathies like diffuse dilatation or aneurysms. This report describes an interesting case of embolic acute ischemia, caused by a persistent sciatic artery with an aneurysm. We treated the ischemia with intra-a. lysis and bridged the aneurysm with an covered stent.

Acute Disease↗
PubMed2000

MRI in the diagnosis of small bowel disease: use of positive and negative oral contrast media in combination with enteroclysis.

The aim of the study was to evaluate the additional findings of MRI following small bowel enteroclysis and to compare the efficacy of negative and positive intraluminal contrast agents. Fifty patients with inflammatory or tumorous small bowel disease were investigated by small bowel enteroclysis and consecutive MRI using breathhold protocol (T1-weighted fast low-angle shot, T2-weighted turbo spin echo). Patients were randomly assigned to either receiving a positive oral (Magnevist, Schering, Berlin, Germany) or a negative oral MR contrast media (Abdoscan, Nycomed, Oslo, Norway). The pattern of contrast distribution, the contrast effect, presence of artifacts, as well as bowel wall and extraluminal changes, were determined and compared between the contrast type using Fischer's exact test. Sensitivity, specificity, and diagnostic accuracy for MRI and enteroclysis were calculated. Twenty-seven patients had clinically proven Crohn's disease and two patients surgically proven small bowel tumours. Magnetic resonance imaging had important additional findings as abscesses and fistulae in 20 patients. Surgically compared sensitivities were 100 and 0% for MRI and enteroclysis, for the detection of abscesses, and 83.3 and 17 % for the diagnosis of fistulae, respectively. Bowel wall thickening was more reliably detected with use of positive oral contrast media without intravenous enhancement (p < 0.001), whereas postcontrast negative oral contrast media allow for a superior detection (p < 0.001). T2-weighted sequences were necessary with use of negative oral contrast media, because loop abscesses may be masked. Magnetic resonance imaging should be performed in all patients with suspicion of extraintestinal complications, because the complications are more reliably detected by MRI. Negative oral contrast media show advantages with the use of intravenous contrast but can mask loop abscesses using only T1-weighted imaging.

Abscess↗
PubMed2000

Diagnosis of papillomas of the breast: value of magnetic resonance mammography in comparison with galactography.

The aim of this study was evaluation of MRI alone and in combination with mammography and galactography in the diagnosis of intraductal papillomas. From 1994 to 1998, a total of 48 women presenting with pathologic mammary secretion underwent galactography and magnetic resonance mammography (MRM). Thirty-five patients aged 16-71 years (average age 46 years) subsequently underwent surgery or diagnostic puncture and the histologic findings were compared with the results of the radiologic examination. Histology revealed papillomas in 16 cases. In 6 of these patients, there was associated malignant degeneration. Malignancy without associated papilloma was observed in 3 cases. Galactography displayed a sensitivity of 94% and a specificity of 79% with five false-positive findings and one false-negative finding in the recognition of intraductal papillomas. Malignant processes were detected by mammography/galactography in only one instance. Magnetic resonance mammography visualized pathologic contrast medium uptake in 8 of 9 cases of malignant disease (sensitivity 89%). One patient with in situ ductal carcinoma escaped detection with MRM. Papillomas showed no or below-the-threshold-lying contrast uptakes with no specific sign suggestive of papilloma. Galactography in combination with mammography remains the primary diagnostic procedure in cases of pathologic mammary secretion or suspected papilloma. The addition of MRI permits exclusion of malignant disease with a high degree of certainty; thus, expectant management in individual cases with negative findings appears justified.

Breast↗
PubMed2000

Brain activation during human navigation: gender-different neural networks as substrate of performance.

Visuospatial navigation in animals and human subjects is generally studied using maze exploration. We used functional MRI to observe brain activation in male and female subjects as they searched for the way out of a complex, three-dimensional, virtual-reality maze. Navigation activated the medial occipital gyri, lateral and medial parietal regions, posterior cingulate and parahippocampal gyri as well as the right hippocampus proper. Gender-specific group analysis revealed distinct activation of the left hippocampus in males, whereas females consistently recruited right parietal and right prefrontal cortex. Thus we demonstrate a neural substrate of well established human gender differences in spatial-cognition performance.

Adult↗
PubMed2000

Does successful embolization of endoleaks lead to aneurysm sac shrinkage?

PURPOSE: To determine whether embolization of endoleaks after endovascular repair of aortic aneurysms is associated with a decrease in the diameter of the aneurysm. METHODS: Fifteen patients (13 men; median age 76 years) demonstrated primary endoleaks persisting > or =3 months after endovascular abdominal aortic aneurysm repair with a variety of commercial endografts. In 8 patients, coil embolization failed to completely obliterate the leak, whereas embolotherapy proved successful in the remaining 7 patients. Surveillance of endoleaks and the effect of their embolization on aneurysm size were followed with serial computed tomographic (CT) scans. Follow-up after embolization extended for at least 12 months. RESULTS: Patients with persistent leak exhibited a slight increase in mean aneurysm area from 21.41+/-4.25 to 22.47+/-6.70 cm2. Medians differed from 20.03 (range 16.59-28.73) to 23.03 (range 14.14-33.69) cm2 (p = 0.0078, 95% confidence interval [CI] = 0.0075 to 0.0081). Successfully treated patients, however, showed a mean decrease from 20.58+/-3.63 (median 19.87) to 16.36+/-6.46 cm2 (median 18.10) at 1 year (p = 0.0156, 95% CI = 0.0151 to 0.0160). The medians differed significantly between groups (p < 0.05). CONCLUSIONS: Persistent endoleaks after endovascular aortic aneurysm treatment led to an increase in the diameter of the aneurysm, whereas complete occlusion was associated with a significant decrease in aneurysm diameter.

Aged↗
PubMed2000

MRI with mangafodipir trisodium in the detection of pancreatic tumours: comparison with helical CT.

The aim was to compare spiral CT and MRI enhanced with mangafodipir trisodium (Mn-DPDP) in the detection and staging of pancreatic lesions. 20 patients with suspected pancreatic cancer were included in a phase III study. Triphasic spiral CT (4 ml s-1) and MRI (axial T1 weighted turbo spin echo with and without fat suppression, T1 weighted gradient echo and T2 weighted turbo spin echo at 1.5 T) were performed. All sequences were repeated following contrast medium using the same instrument settings as in the unenhanced sequences. Mn-DPDP was administered by slow injection of 5 mumol kg-1 body weight. Imaging results were correlated with surgery, laparoscopy, biopsy and/or follow-up. Eight pancreatic adenocarcinomas were present. Ten patients had chronic pancreatitis, and two showed a stenosing papillitis. CT detected eight malignant lesions and MRI detected seven. One pancreatic cancer was not detected with MRI. CT and MRI excluded malignancy in nine patients. MRI and CT returned three false positive results. Mn-DPDP improved delineation of the lesion, resulting in a higher level of diagnostic confidence. Differentiation between pseudotumorous lesions in chronic pancreatitis and pancreatic carcinoma was difficult due to similar slight contrast enhancement. Owing to better delineation of the lesion and the higher confidence in diagnosis, MRI with Mn-DPDP may have the potential to improve the detection rate and the staging accuracy of focal pancreatic lesions. These results need to be confirmed in a larger patient trial.

Adult↗
PubMed2000

[Double-helical CT pitfall: the native hyperdense basilar artery].

PURPOSE: The unenhanced signs of basilar thrombosis at computed tomography (CT) is the hyperdense visualization of the basilar artery due to intravascular thrombosis. In patients who are clinically asymptomatic, hyperdense visualization of the basilar artery can be observed, if scanned with a double helical CT. Purpose of the present study was to evaluate the diagnostic significance of these changes seen at double-helical CT. MATERIAL AND METHOD: Ten patients patients underwent double-helical CT of a portion of the base of the skull. In each case, 5-mm and 10-mm fused slices were obtained. The patency of the visualized vessels was then documented using contrast-enhanced images. RESULTS: The differences in attenuation between the 5-mm and 10-mm fused slices obtained at native examinations were a median 11 HU. Subsequent contrast enhanced studies documented patency of the examined vessels. CONCLUSION: The present data show that the hyperdense basilar artery as a sign of thrombotic occlusion is not valid when thin, fused slices are obtained at double-helical CT.

Adult↗
PubMed2000

Functional cranial neuronavigation. Direct integration of fMRI and PET data.

OBJECTIVE: We report our first experiences with the direct integration of fMRI data into cranial neuronavigation. METHOD: For navigation we used the MKM system and thin-sliced T1 contrast enhanced images. As a first step 21 patients had fMRI for localization of the precentral gyrus, 2 patients for Broca area detection. By anatomical correlation, these functional data were indirectly compared to the intraoperative findings using cortical SSEP (n=20) or cortical stimulation (n=3). Encouraged by these preliminary results, we started the direct integration of fMRI into neuronavigation in June 1999, followed by PET in January 2000, enabling us to compare functional images with intraoperative findings directly. fMRI and PET data were integrated by landmark matching referring on skin fiducials. Meanwhile, fMRI data of 8 patients (6 motorcortex, 2 Broca) and PET images of 1 patient were directly integrated into neuronavigation. Six out of 8 patients had additional cortical monitoring, 2/8 were exclusively operated on by functional neuronavigation. RESULTS: Using indirect comparison between fMRI and intraoperative findings we observed a good correlation in every case for the motorcortex, but only in 1/2 for the speech area. In all 6 direct integrated fMRI cases, these findings corresponded well to the conventional ones. Both patients with sole functional navigation did not have any postoperative neurological deficit. The inaccuracy of the fMRI ifT1 matching was 2. 7 mm (sigma=0.9 mm) and 1.3 mm (sigma=0.4 mm) of the subsequent referenciation of the navigation. The tumor delinement shown by 11C-methionine PET could be proven by intraoperative biopsy outside its indicated tumor margin. The inaccuracy of the PET matching was 0. 8 mm. CONCLUSION: Functional neuronavigation enables to visualize and preserve relevant brain areas. Other functional areas like short-term memory, which solely can be detected by fMRI might also be monitored in the future. The integration of PET data expect to gain a better differentiation of tumor and edema.

Adult↗