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Biomedical subjects

J Neuerburg

Publications and source records attributed to J Neuerburg.

At least 55 records · Page 3Linked to original sources
PubMed1993

[The MR morphology of hemangiomas and lymphangiomas of the peripheral soft issues--a correlation with angiography and histology].

A retrospective analysis of the morphology and signal behaviour of T1, proton and T2-weighted spin-echo sequences has been carried out on 21 haemangiomas and 2 lymphangiomas of the peripheral soft tissues which had been examined by MRT. In 11 cases the diagnosis was confirmed histologically and in 12 by angiography. The majority of haemangiomas (19 cases) and both lymphangiomas showed hyperintense signals on T2-weighted spin-echo sequences; 2 lesions did not conform to this behaviour. MRT was a sensitive method for demonstrating vessels with high flow velocities so that it was possible to distinguish high flow haemangiomas by MRT. Apart from one thrombosed haemangioma, all 9 haemangiomas examined with iv Gd-DTPA showed homogeneous contrast uptake except for vessels with high flow velocities. One lymphangioma examined with iv Gd-DTPA was characterised by non-homogeneous contrast uptake.

Angiography, Digital Subtraction↗
PubMed1992

[MR tomography of colorectal diseases with a negative rectal contrast medium].

The potential of the generic kaopectate (Upjohn) as a negative rectal contrast agent in MR imaging was investigated in the assessment of colorectal disease. 45 MR examinations in patients with colorectal disease (colorectal carcinoma 25 patients, inflammatory disease 12 patients, miscellaneous disorders of the colon 8 patients) were evaluated. All examinations were performed with T1 and T2 weighted SE sequences after rectal application of kaopectate. Gd-DTPA enhanced T1 SE sequences were obtained as well. Kaopectate revealed a signal void of the lumen of the large intestine in T1 and T2 weighted SE sequences. Intravenous administration of Gd-DTPA enabled good differentiation of contrast-enhanced malignant or inflammatory tissue and the low signal lumen of the bowels. No side effects were noted.

Adult↗
PubMed1991

Muscle cross-section measurement by magnetic resonance imaging.

Muscle cross-section areas were measured by magnetic resonance imaging (MRI) in the thigh of a human cadaver, the results being compared with those obtained by photography of corresponding anatomic macroslices. A close correlation was found between MRI and photographic evaluation, differences between the methods ranging from nil to 9.5%, depending on the scan position and the muscle groups. In vivo MRI measurements were performed on 12 female and 16 male students, the objectivity, the test-retest reliability and the variability of the MRI measurements being studied by fixing the scan position either manually or by coronary scan. The latter method appeared to be more objective and reliable. The coefficients of variation for muscle cross-section areas measured by MRI were in the range of those for the planimetry of given cross-section areas. Allowing for differentiation between several small muscle bundles in a given area, MRI proved to be a suitable method to quantify muscle cross-sections for intra- and interindividual analysis of muscle size.

Adult↗
PubMed1991

[Intravascular ultrasound for support in percutaneous interventional treatment].

The potential of intravascular ultrasound (IVUS) as an adjunct to angiography was investigated in 54 interventional procedures (13 venous lesions, 41 arterial lesions: stent placement in 31, atherectomy in 7, balloon dilation in 6, thrombectomy in 5, placement of vena cava filters in 3, foreign body retrieval in 2 cases). IVUS offered additional information to angiography in 30 cases; the therapeutic concept was changed because of IVUS findings in 18 cases. Severity of dissections or stenoses was more accurately depicted by IVUS compared to angiography. IVUS allowed an exact measurement of vessel diameter and a correct positioning of stents and caval filters.

Catheterization, Peripheral↗
PubMed1990

Magnetic resonance imaging of acute and long-term alterations following extracorporeal shock wave lithotripsy in rats.

The kidneys of 30 rats were treated by extracorporeal shock wave lithotripsy (ESWL) with different doses of extracorporeal shock waves: 500, 1,000 and 2,000. The animals were sacrificed after 24 h, 7, 14 or 35 days. Magnetic resonance (MR) imaging at 1.5T was used to evaluate the effects of ESWL on T1- and T2-weighted (spin echo 600/22, 1,600-2,000/90) images compared to histology and macroscopy. The severity of pathologic changes correlated dose dependently with the number of shock waves given (500-2,000). The MR findings following ESWL in 50 kidneys included diffuse loss of the corticomedullary junction (n = 20), perirenal and subcapsular fluid (n = 23), intrarenal foci of increased (n = 16) or decreased (n = 8) signal intensity, and loss of distinction between renal, splenic or hepatic contours (n = 7), detected macroscopically as adhesions. Subcapsular and intrarenal findings corresponded to acute hematomas and organized fibrotic tissue morphologically. In long-term groups MR revealed fibrotic shrinkage of the renal convexity as indentation of the kidney surface (n = 12). MR imaging is a sensitive method for the detection of specific alterations following ESWL, especially intrarenal changes, which are important for possible long-term lesions after ESWL.

Animals↗
PubMed1990

Gadolinium-enhanced magnetic resonance imaging in the staging of urinary bladder neoplasms.

Magnetic resonance imaging (MRI) proved to be an important diagnostic tool in the correct staging of bladder neoplasms. The advantage of multiplane imaging and high soft-tissue contrast may be extended by the use of MRI contrast media such as the gadoliniumdiethylene-triaminepentaacetic acid complex. In 60 patients with suspected or proved bladder tumors, the results of preoperative gadolinium-enhanced MRI were correlated with the histopathologic findings. The staging accuracy of infiltrating tumors was 83% and sensitivity and specificity 86% and 83%, respectively. Three tumors could only be localized after administration of gadolinium. All active tumors demonstrated significant contrast enhancement after intravenously injected gadolinium. Small papillary tumors or carcinoma in situ remain problematic to preoperative staging procedures. The advantages of gadolinium-enhanced MRI will best be employed in the exact pretherapeutic staging of infiltrative bladder neoplasms or in restaging procedures after chemotherapy and radiotherapy.

Adenocarcinoma↗
PubMed1990

[Carcinoma in a Zenker's diverticulum. Contribution of computed tomography and magnetic resonance tomography].

A case of carcinoma arising in a posterior pharyngeal pulsion diverticulum is reported. The radiologic work-up included computed tomography and magnetic resonance. Both these modern cross-sectional imaging methods allow conclusive differentiation of filling defects, which is known to be difficult in many cases with conventional imaging techniques. Filling defects due to carcinoma are easily recognized and differentiated from those caused by inspissated food debris as they are enhanced following i.v. administration of contrast medium. In addition, the depth of infiltration can be established.

Aged↗
PubMed1989

The value of magnetic resonance imaging at 1.5 T in the evaluation of the scrotal content.

50 patients with a broad variety of scrotal disorders were evaluated in form of a prospective study by high-resolution scrotal sonography and magnetic resonance imaging at 1.5 T with high-resolution surface coils. Basic anatomic correlations to normal structures of the scrotum were studied in 4 fresh cadaver testicles without pathology. Magnetic resonance imaging is sensitive and specific, but time-consuming and expensive.

Genital Diseases, Male↗
PubMed1988

[Paget's disease of bone: MR characteristics at 1.5 T].

Thirteen patients with confirmed Paget's disease were examined using a 1.5 T MR tomograph. Five patients had polyostotic and eight patients monostotic forms of the disease. The results of these MR examinations were compared with the results of MR examinations performed on patients with osseous changes of different origin (metastases of breast cancer and prostate cancer, osteomyelitis, bone marrow infiltration due to acute lymphatic leukaemia and plasmocytoma). MR tomography permits evaluation of bone marrow space, osseous changes, and the surrounding soft tissue. Areas of sclerotic bone, thickened corticalis and bands of connective tissue in the marrow space were recognised as structures with no signal in T1- and T2-weighted images. The red and yellow marrows showed normal signal intensity patterns, although they were often reduced in size.

Aged↗
PubMedDate not supplied

Gadolinium-enhanced T1-weighted versus T2-weighted imaging of scrotal disorders: is there an indication for MR imaging?

To evaluate the use of gadopentetate dimeglumine in magnetic resonance (MR) imaging of scrotal disorders, the clinical, ultrasound, and MR imaging data of 29 patients (age range, 19-75 years) with various intra- and extratesticular disorders were retrospectively analyzed. T1- and T2-weighted spin-echo images (T1-T2 group) were compared with T1-weighted spin-echo images before and after intravenous administration of gadopentetate dimeglumine (T1-Gd group). A receiver operating characteristic (ROC) analysis of the findings was undertaken. Better contrast between tumor and parenchyma and a clearer demonstration of the tunica albuginea were noted in the T1-T2 group (although not of diagnostic relevance). ROC analysis revealed no differences between the two imaging groups in the diagnosis of tumor, trauma, hydrocele, or hemorrhage; however, epididymitis was diagnosed more easily with contrast enhancement (0.8834 vs 0.7759, P = .04) and the diagnosis of orchitis was expressed more strongly (0.8221 vs 0.7184, P = .17). Four of the five observers were more confident in making the diagnosis with contrast enhancement. With MR imaging, the diagnosis was correctly suggested in three patients in whom clinical and ultrasound data were inconclusive. Gadolinium-enhanced MR imaging gives additional information in scrotal disorders and facilitates diagnosis. It may be helpful when findings at physical examination and ultrasound differ and when plain T1- and T2-weighted images are equivocal.

Adult↗
PubMedDate not supplied

Gd-DTPA-cascade-polymer: potential blood pool contrast agent for MR imaging.

Gadolinium-DTPA (diethylenetriaminepentaacetic acid)-cascade-polymer, a potential new blood pool contrast agent for magnetic resonance (MR) imaging, was compared with a known blood pool agent, Gd-DTPA-polylysine, in an animal model. The relative signal intensities of liver, renal cortex, pancreas, and trunk muscle were assessed in 12 pigs between 4 seconds and 120 minutes after injection of a 20 mumol/kg dose of each contrast agent, by using a FLASH (fast low-angle shot) sequence. Except for muscle, all tissues showed visible enhancement after injection of either contrast agent. After injection of Gd-DTPA-polymer, enhancement patterns in the liver, renal cortex, and pancreas were similar to those seen after injection of Gd-DTPA-polylysine. No statistically significant differences in enhancement between the two contrast agents were found at any time point. The authors conclude that the contrast kinetics of Gd-DTPA-cascade-polymer are similar to those of Gd-DTPA-polylysine and that this agent may also be used as a blood pool contrast agent for MR imaging.

Animals↗
PubMedDate not supplied

Visualization of MR-compatible catheters by electrically induced local field inhomogeneities: evaluation in vivo.

The purpose of this study was to assess the feasibility of a newly developed field inhomogeneity catheter for interventional MRI in vivo. Different prototypes of a field inhomogeneity catheter (pigtail and multipurpose configuration, balloon catheters) were investigated in pigs. The catheters were introduced in Seldinger technique via the femoral vessels over a guidewire on an interventional MR system (Philips Gyroscan NT combined with a C-arm fluoroscopy unit [Philips BV 212]). Catheters were placed in veins and arteries. The catheter position was controlled by a fast gradient-echo sequence (turbo field echo [TFE]). Catheters were introduced over a guidewire without complications in all cases. Using the field inhomogeneity concept, catheters were easily visualized in the inferior vena cava and the aorta by the fast gradient-echo technique on MR in all cases. Although aortic branches were successful cannulated, the catheters were not well displayed by the TFE technique due to the complex and tortuous anatomy. All animals survived the experiments without complications. MR-guided visualization of a field inhomogeneity catheter is a simple concept that can be realized on each MR scanner and may allow intravascular MR-guided interventions in future.

Animals↗
PubMedDate not supplied

Neointima formation following arterial placement of self-expanding stents of different radial force: experimental results.

PURPOSE: Radial force delivered by self-expanding stents has been discussed as a factor affecting thickness of neointima formation. METHODS: Two types of Wallstents were studied experimentally in vitro and in vivo. Due to an altered braiding angle of the stent filaments, one stent type (LS type) delivers half the radial force to the vascular wall than the conventional type. The radial force was evaluated in a compression-expansion test which related changes in stent length to the compressing force. Fourteen LS and 16 conventional stents were implanted into 15 femoropopliteal arteries of 10 dogs. Autopsy was performed after 4 weeks (14 stents) or 6 months (16 stents). RESULTS: All stents remained patent over the follow-up period with no evidence of stenosis. Neointimal overgrowth was complete and smooth in all. Medial atrophy was a constant finding after placement of both types. Neointimal thickness did not exceed 100 microns after 4 weeks and 6 months and did not significantly differ between LS stents and conventional stents. CONCLUSION: It is concluded that in normal dogs self-expanding stents of the Wallstent type do not induce neointimal buildup that exceeds 100 microns in the femoropopliteal artery. A reduced radial force was not found to result in reduced neointima formation.

Animals↗
PubMedDate not supplied

Iliocaval stenosis and iliac venous thrombosis in retroperitoneal fibrosis: percutaneous treatment by use of hydrodynamic thrombectomy and stenting.

A case of bilateral iliac stenosis and caval stenosis due to retroperitoneal fibrosis was treated by caval stenting and iliac balloon angioplasty, but was complicated by subsequent iliac thrombosis. Venous thrombectomy was successfully achieved by hydrodynamic thrombectomy, and iliac patency was stabilized by bilateral stent insertion.

Angioplasty, Balloon↗