PubMed Health⌕ Search

Biomedical subjects

T Hilbertz

Publications and source records attributed to T Hilbertz.

14 recordsLinked to original sources
PubMed1992

[Visualized three-dimensional reconstruction and image analysis in orthopedics and trauma surgery].

Computer tomography is a commonly used technique for detecting pathological alterations in soft tissue and the skeleton. The remote access to image informations as well as the allocation of display and processing tools via networks enables improved diagnostic and therapeutic practice in orthopaedic and traumatologic surgery. The realization of a user friendly image analysis system displays and processes the acquired images in a modality oriented manner. Our method is based on a unique file format and specific evaluation procedures to produce the input data for three-dimensional display and algorithms for the individual design of implants. Our image analysis system can process the data of conventional computer tomographies with three or more mm distance. In contrast to the available systems there is a low significance of radiation effects.

Computer Graphics↗
PubMed1992

[Pre- and postoperative NMR tomographic studies in avascular femur head necrosis].

46 patients with avascular necrosis of the femoral head were examined by T2- and T1-weighted MR before and after infusion of Gd-DTPA. Both sides were involved in 12 cases. The classification was done according to Ficat. In early stages and in postoperative studies a correlation of signal intensity after infusion of Gd-DTPA and clinical symptoms was found. Hyperintensity of the avascular area or of the implanted material was assumed to be vascularised or vital components in 4 cases of Ficat I and in 15 postoperative studies. Contrariwise, we found in 5 patients with severe postoperative symptoms, low signal intensity areas due to avascular regions.

Contrast Media↗
PubMed1992

[Acute cholecystitis: percutaneous transhepatic drainage].

Despite emerging endoscopic techniques for treatment of gallbladder diseases the operative cholecystectomy is the treatment of choice in acute cholecystitis. Percutaneous cholecystostomy is an alternative treatment modality in poor surgical risk patients. In 19 out of 36 patients with percutaneous cholecystostomy no subsequent cholecystectomy was performed. A long-term observation of these 19 patients showed normal function of the gallbladder in ultrasound studies, thus percutaneous drainage can be a definitive treatment for acute cholecystitis in selected cases.

Aged↗
PubMed1992

Visualization of multimodal image information in medicine.

Radiological and clinical practice can be enhanced by improved access to multimodal image informations. Analysis, visualization, method characteristic image processing and image synthesis is needed not only for the interpretation of the images but also for performing effective consultations with clinical colleagues and computer supported therapy planning and control strategies. The distributed system RADVIS (radiological visualization) is presented which enables the fast display, three dimensional visualization and the modality oriented analysis of multimodal image informations. Based on a unique image format, modality specific evaluation procedures and two- or three dimensional processing tools of image analysis produce the input data for therapy planning programs. The easy use of this multimedia visualisation tool enables radiologists and clinicians to deal with their image data. The description of methods and procedures of the prototype, as well as typical examples of radiologic practice will demonstrate the efficiency of the presented system.

Humans↗
PubMed1991

[Digital peripheral angiography with pace shifting and subtraction. Comparison with the standard procedure].

In a prospective randomised study including 60 patients digital peripheral angiography with stepping and subtraction (DPSA) was compared to DPA without subtraction (DPA), DSA without stepping and conventional angiography. Using conventional angiography, complementary series were necessary in 8 out of 20 patients. This number could be reduced to 3 out of 20 patients using DPSA and DSA respectively. Examination time could thus be shortened by about 20%. The amount of contrast medium could also be reduced by 15 to 20%. Both digital subtraction techniques supplied superior image quality especially in the lower limb in comparison with conventional and digital peripheral angiography without subtraction. X-ray exposure was similar for conventional angiography and DPSA. DSA without subtraction revealed a three times increased dose. Our results indicate that DPA with the possibility of image subtraction is a desirable new technique and might become the method of choice in peripheral angiography in the future.

Angiography↗
PubMed1990

[Use of digital subtraction arthrography in lesions of the rotator cuff--comparison with ultrasound].

60 patients with suspected lesion of the rotator cuff were examined by digital subtraction arthrography and the results were compared to ultrasound. The dynamic study of digital subtraction arthrography visualised in 22 of 23 complete or incomplete cuff tears the exact location of the extravasation of the contrast medium. All diagnoses were confirmed by surgery. Problems of conventional arthrography were not seen by the digital method.

Acromioclavicular Joint↗
PubMed1989

MR imaging of the breast with Gd-DTPA: use and limitations.

Between August 1985 and November 1987, 150 patients with 167 biopsy-proved lesions were examined with magnetic resonance (MR) imaging enhanced with gadolinium diethylenetriaminepentaacetic acid, mammography, and palpation. Of these patients, 113 with 123 lesions were also examined with ultrasound. Enhancement above 300 normalized units (NU) on MR images was considered significant; between 250 and 300 NU, borderline; and below 250, nonsignificant. All 27 fibroadenomas and 70 of 71 carcinomas showed significant enhancement; one carcinoma showed borderline enhancement. Nonproliferative dysplasia showed nonsignificant enhancement in 15 of 16 cases and significant enhancement in one, whereas proliferative dysplasia showed usually diffuse enhancement varying from nonsignificant (five of 30 cases) to borderline (five of 30 cases) to significant (20 of 30 cases). In the nonblind evaluation of the modalities, MR imaging compared favorably. When limitations of the technique were considered, MR imaging seemed beneficial as a supplement in selected, diagnostically difficult cases.

Adenofibroma↗
PubMed1988

[Endocrine orbitopathy: a comparison of computerized tomographic results and orthoptic findings].

The correlation between the loss of function of the extrinsic rectus eyemuscles and their appearance on computed tomography images in patients with Graves' disease was examined. Pathologic changes of a single rectus eyemuscle normally blockade the movement of the corresponding antagonistic muscle. This is caused by the impossibility to relax due to fibrotic alterations. Nevertheless there are some hints, which indicate, that in some cases, especially concerning the lateral rectus muscle, the inherent function of the thickened muscle is restricted.

Adult↗
PubMed1988

[Dynamic contrast medium studies with flash sequences in nuclear magnetic resonance tomography of the breast].

In this study the dynamic contrast behavior after Gd-DTPA of different breast tissues and tumors has been investigated with a series of T1-weighted FLASH-sequences during the first 5 minutes after the application of Gd-DTPA. The results of these dynamic FLASH-measurements have been compared to the results of the SE-sequences 6-10 and 11-15 minutes after Gd-DTPA in 40 patients with 54 different breast tissues. It could be shown that in a number of cases a better differentiation (e.g. DD between carcinomas and proliferative dysplasia) was possible on FLASH-scans early after contrast medium than on the late SE-scans. Only the distinction between non-proliferative and proliferative dysplasia was better on the late SE-scans. Evaluation of the enhancement dynamics may be helpful in some cases as an additional information. Further investigations are necessary to confirm these findings and to assess their value.

Breast↗
PubMed1986

[Computed tomography in endocrine orbitopathy: the effects of varying gantry tilt and patient positioning on the measurement of eye muscle thickness and the possibilities for correction].

Thickening of eye muscles in endocrine orbitopathy can be demonstrated particularly impressively in coronary computed tomograms. However, when measuring the height and width of rectus eye muscles manifesting pathologic changes, the measurement is increased by a deviation from the coronary section plane; this is due to different tilting of the gantry. This often leads to an incorrect stage classification and makes objective observation of the course (e.g., under therapy) impossible. By converting the measured values into the actual extent of the muscles by means of the cosine set, appreciable changes in the pattern and frequency of affection of the rectus eye muscles were found in 121 patients examined.

Adult↗
PubMedDate not supplied

Peripheral DSA with automated stepping.

Peripheral digital angiography can be applied with automated stepping and in digital subtracted technique to evaluate the complete lower extremities angiographically with one single injection of contrast medium. Altogether 25 DSA-examinations were compared with non-substracted technique. By DSA-technique additional series could be reduced to only those, where significantly different flow in both extremities necessitated different timing as known from conventional angiography. DSA-technique with automated stepping may in the future totally replace conventional angiography of the peripheral arteries.

Angiography↗
PubMedDate not supplied

Gd-DTPA enhanced MR imaging of the breast in patients with postoperative scarring and silicon implants.

Sixty patients with postoperative scarring with (30) or without (30) silicon implants have been examined by magnetic resonance (MR) with Gd-diethylenetriamine pentaacetic acid. The 60 patients consisted of 28 patients with obvious normal or abnormal findings and of 32 diagnostically difficult patients, who were referred to MR because of uncertain mammographic and/or clinical findings. Scarring older than 6 months postoperatively did not enhance noticeably, whereas scarring younger than 6 months postoperatively enhanced variably (nonsignificant, borderline, or significant). Since all carcinomas larger than the slice thickness enhance significantly (as also confirmed by other studies) contrast enhanced MR allowed an excellent discrimination between scarring older than 6 months and malignancy. Good visualization of the tissue around silicon implants proved to be another advantage of MR. When its use in the diagnostically difficult cases was analyzed, MR proved quite helpful in 23 of 32 cases by excluding or demonstrating malignancy.

Biopsy↗
PubMedDate not supplied

Administration of gadopentetate dimeglumine in MR imaging of intracranial tumors: dosage and field strength.

PURPOSE: To investigate the efficacy of 0.025, 0.05 and 0.1 mmol/kg gadopentetate dimeglumine in MR imaging of patients with intracranial tumors at mid and high field strength. METHODS: In 88 patients, an open-label phase III multicenter dose-finding study was performed at 0.5, 1.0, and 1.5 T MR units. Before and after (5, 15, 25 minutes) intravenous administration of gadopentetate dimeglumine, imaging was performed with T1-weighted spin-echo sequences. RESULTS: With 0.1 mmol/kg yielding the highest values, tumor enhancement and numerical tumor/brain contrast showed dose-dependent 5-minute postcontrast values (P less than 0.05). Compared to 5-minute postcontrast values, there was no significant change at 15 and 25 minutes. Although the lowest values of enhancement were found at 0.5 T, differences in enhancement among the field strengths were not statistically significant. The numerical data were confirmed by visual assessment of tumor/brain contrast. Eighty to 90% of cases had diagnostically valuable enhancement at 0.1 mmol/kg, 50% at 0.05 mmol/kg, and 10% at 0.025 mmol/kg (P less than 0.05). There were no adverse events. CONCLUSION: Our results confirm that 0.1 mmol/kg gadopentetate dimeglumine is more effective at enhancing intracranial tumors than lower doses at mid and high field MR units.

Adult↗