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Biomedical subjects

J Biederer

Publications and source records attributed to J Biederer.

32 records · Page 2Linked to original sources
PubMed2001

[Value of kinematic MRI in the evaluation of patients with exacerbated pain in cervical spine motion compared with static MRI].

OBJECTIVE: To assess the clinical value of kinematic MR imaging in patients with cervical radiculopathy and increasing symptoms after provocative maneuvers at flexion, extension, axial rotation and coupled motion of the cervical spine. METHODS: Thirty-five patients with cervical disc herniation or cervical spondylosis in whom symptoms were elicited at flexion, extension, axial rotation and coupled motion were studied inside a positioning device using T2-weighted TSE, 2D-FLASH, and reformatted 3D DESS and 3D-FISP sequences. The images were evaluated for the size of disc herniations, the foraminal size and cervical cord displacement at provocative position compared with neutral position (0 degree). In addition, the value of kinematic MR images were interpretated with regard to changes in the therapeutic procedure and intraoperative patient positioning. RESULTS: Compared with the neutral position (0 degree) a change in disc herniations was not found in any (0%) of the provocative positions. In five patients (14%) cervical cord displacement was noted at axial rotation. The foraminal size varied depending on the provocative position, increasing at flexion and decreasing at extension. CONCLUSION: Kinematic MR imaging in patients with cervical radiculopathy and increasing symptoms at provocative maneuvers provides no additional information for the therapeutic decision-making process.

Biomechanical Phenomena↗
PubMed2001

[Comparison of biphasic spiral CT and MnDPDP-enhanced MRI in the detection and characterization of liver lesions].

INTRODUCTION: To evaluate the efficacy of biphasic spiral CT and MnDPDP (Teslascan, Nycomed Amersham) enhanced MR imaging to detect and classify liver lesions. MATERIALS AND METHODS: 39 patients with known or suspected liver lesions were included into this study and examined with biphasic spiral CT and MnDPDP-enhanced MRI. 25 histological reports and 1 extreme increased serum AFP value could be obtained from 22 patients, therefore only these 26 proven lesions were included into this analysis. RESULTS: From 39 patients CT revealed in 54% (14 lesions) and MRI in 54% correct (i.e., corresponding to the histology) diagnosis. Correct CT/wrong MRT diagnosis and vice versa was present in only 2 lesions each. Differentiating into benign versus malignant lesion was successful in 73% for MRI and 77% for CT. In 81% MRI revealed the correct type of lesion (hepatocellular or non-hepatocellular) vs. 77% with CT. Sensitivity/specificity for differentiation into benign/malignant lesions was 86%/70% (MRI) and 87%/77% (CT) and for differentiation of the lesions origin 100%/80% (MRI) and 80%/75% (CT), these differences were not significant. MnDPDP-enhanced MRI showed significantly more lesions than non-enhanced MRI. CONCLUSION: MnDPDP-enhanced MRI is better than CT in differentiating hepatocellular liver lesions from non-hepatocellular lesions. After contrast enhancement with MnDPDP significantly more lesions could be evaluated in MRI. MnDPDP improves, in combination with biphasic helical CT, the diagnosis of liver lesions.

Adenoma↗
PubMed2001

Magnetic resonance imaging of the lung with a volumetric interpolated 3D-gradient echo sequence.

OBJECTIVE: To evaluate the feasibility of a magnetic resonance imaging protocol for the lung using a volumetric interpolated 3D-gradient echo sequence (3D-GRE). SUBJECTS AND METHODS: A T(1)-weighted 3D-GRE sequence was used for volumetric interpolated breath-hold examinations ("VIBE") of the lung in twelve healthy volunteers (TR/TE 4.5/1.9 ms, flip-angle 12 degrees, matrix 502 X 512 [interpolated]). Three coronal 80 mm slabs (16 aportitions, 2.5 mm slices) were added to 3D data sets for multi-planar reformations. No contrast material was applied. Artifacts and resolution o vessel and airway structures in each lung segment were evaluated by two observers (12 volunteers, 228 lung segments). RESULTS: The protocol provided excellent images of vascular and tracheo-bronchial structures with very moderate pulsation artifacts. 224/228 lung segments were imaged with "good" (146/228) or "sufficient" quality (78/228). Segmental and sub-segmental vessels (5th order) were identified due to bright flow signal without administration of contrast material. Walls of segmental bronchi (3rd order) were delineated in all parts of the lung. CONCLUSIONS: The high spatial resolution, the excellent visualization of lung anatomy, the low rate of artifacts without respiratory triggering and the short acquisition times are clear advantages of the 3D-GRE (VI-BE) sequence compared to existing 2D-GRE strategies for MRI of the lung.

Adolescent↗
PubMed2000

Spontaneous intracranial haematomas caused by neoplasms.

We report about 50 patients with spontaneous intracerebral haematomas (ICH) caused by intracranial neoplasms to assess the underlying histological condition, their presentation on admission, diagnostic work-up, treatment, histological diagnosis, and clinical outcome. These patients were identified in a prospective series of 2041 patients with intracranial neoplasms and 692 patients with spontaneous ICH, which were both consecutively collected over a nine-year-period. The frequency of ICH in patients with intracranial neoplasms was 2.4%. The frequency of tumour related ICH in the ICH group was 7.2%. The leading cause of tumour related ICH were metastases of extracranial origin (n = 18; 36%), followed by glioblastoma multiforme (n = 15; 30%). Nine patients (18%) had benign primary intracranial neoplasms. On admission 18 patients were somnolent (36%) and 14 patients (28%) were comatose. In 29 cases (58%) ICH was the first clinical sign of neoplastic disease, while in 21 patients (42%) a malignant tumour was already known. We operated on 45 patients (90%), four patients (8%) were not operated on because of poor clinical condition and died, one patient refused surgical treatment. Six patients (12%) died despite surgery. This series confirms the importance of a proper neuroradiological and clinical work-up of patients with suspected tumour related ICH followed by operative treatment and histological confirmation of the diagnosis. This is supported by the fact that 18% of patients had prognostically favourable intracranial tumours which would not otherwise have been adequately treated.

Acute Disease↗
PubMed2000

Quantitation of renal perfusion using arterial spin labeling with FAIR-UFLARE.

Quantitative perfusion imaging of human kidneys was performed using arterial spin labeling MRI with a fast spin echo readout-sequence. Perfusion maps of centrally located single slices were obtained in axial and coronal orientations. In ten healthy volunteers, the mean value of perfusion was 213+/-55 mL/(100g min) with a range from 140 to 319 mL/(100g min). These results are in accordance with literature data, considering the fact that FAIR only measures the perfusion component normal to the imaging plane. Intra-individual reproducibility errors of +/-11% were smaller than the natural interindividual variability of renal perfusion (SD = +/- 25%). Perfusion in the cortex was approximately 3-4 times higher compared to the medulla. Considering the relatively high resolution of 2x2x10 mm3, the ability to quantify perfusion, and the lack of ionizing radiation and contrast media, this technique should prove useful in diagnosing renal pathologies that are associated with reductions in tissue perfusion.

Adult↗
PubMed2000

[Digital subtraction angiography of the extremities using step-translation technique].

PURPOSE: To evaluate, how routine application of i.a. DSA with the step-translation technique using a single contrast bolus can effectively reduce radiation exposure and the amount of contrast media in comparison to standard peripheral DSA. METHOD/MATERIALS: 100 patients with peripheral arterial occlusive disease were assessed with step-translation DSA, 100 with standard DSA using the same equipment. Imaging quality was rated two observers, judgement by consensus. Comparison of the technical data (radiation dose, contrast media) was based on pairs of patients with similar constellations of stenoses to reduce selection bias. RESULTS: Step-translation DSA was of high imaging quality from the iliac vessels to the popliteal artery. In the distal leg, imaging was often impaired by effects like unilaterally delayed contrast flow due to high grade stenosis or motion artifacts. 53% of the step translation DSA required 1 or 2, 29% more than two additional DSA runs. Including the additional runs, the average radiation exposure and the amount of contrast media (2434 cGycm2/128 ml) were comparable to those of standard DSA (2461 cGycm2/144 ml). CONCLUSIONS: Step-translation DSA provides high quality images. In routine application realization of the advantages over standard DSA such as reduction of examination times, radiation exposure and amounts of contrast media may be impaired by poorly collateralized stenoses or motion artifacts demanding additional series.

Aged↗
PubMed2000

[Contrast media-enhanced 3D MR angiography before endovascular treatment of aneurysm in the abdominal aorta, iliac artery and peripheral vessels].

PURPOSE: The value of DSA for the measurement of aortic and peripheral arterial aneurysm dimensions before endovascular treatment is limited by projection effects. It was evaluated if additional gadolinium-enhanced three-dimensional MR angiography (3D-CEMRA) could compensate for the disadvantages of DSA. MATERIALS AND METHODS: 21 patients with 35 aneurysms in the abdominal aorta (14), iliac (9) and femoropopliteal vessels (12) were assessed with DSA (7 with calibrated catheter, 14 with yardstick) and 3D-CEMRA (TR/TE 7.8/2.1 ms, flip-angle 40 degrees, Matrix 512 x 224, FOV 500 mm, eff. slice 1.8 mm). We measured and compared aneurysm dimensions on both modalities. 3D-CEMRA was regarded as the reference method to evaluate the dimension of DSA-projection effects. RESULTS: Diameter and length of aneurysms were underestimated on DSA with the yardstick as reference. The deviation ranged from 15% (+/- 5%) in the aorta to 21% (+/- 10%) in the iliac vessels. Only with calibrated catheters as reference (7/21 DSA), were the distances on DSA correlated well with MRA. In 2/35 aneurysms 3D-CEMRA detected thrombosis with difference between length of inner lumen dilatation on DSA and whole aneurysm length. 2/5 accessory renal arteries found on DSA were not detected on 3D-CEMRA. CONCLUSIONS: 3D-CEMRA is a valuable adjunct to DSA for pre-interventional diagnostics of aortic and peripheral arterial aneurysms. It provides exact evaluation of aneurysm dimensions and information about partial thrombosis.

Aneurysm↗
PubMed1999

MR imaging of musculoskeletal trauma to the pelvis and the lower limb.

Magnetic resonance imaging can be used in the trauma setting to detect fractures and associated soft tissue injuries of the musculoskeletal system. Magnetic resonance imaging complements plain radiography and CT for evaluating cancellous bone, cartilage and growth-plate injuries, and intra- and extraarticular supporting soft tissue structures. This review outlines typical applications and imaging consideration for injuries of the pelvis and lower extremity.

Bone and Bones↗
PubMed1999

Late aneurysm formation in a femoro-popliteal polytetrafluoroethylene graft.

Since improvement in the material, true aneurysms and pseudoaneurysm formations have become relatively rare complications after femoro-popliteal reconstruction with polytetrafluoroethylene (PTFE) grafts. We report a case of late graft rupture and pseudoaneurysm formation within the straight femoral part of a femoro-popliteal bypass with reinforced (PTFE-wrapped) Gore-Tex graft. The rupture occurred 7 years after implantation without history of direct traumatization. Intraoperatively the whole bypass showed macro- and microscopically visible deterioration of the wall with almost complete disruption at the site of the aneurysm. The graft had to be replaced completely. In conclusion, we recommend continuous long-term follow-up of these patients preferably with duplex ultrasonography.

Aneurysm, False↗
PubMed1999

[The x-ray follow-up study of the cervical spine after anterior fusion with titanium disk implants].

PURPOSE: We examined the postoperative changes of the cervical spine after treatment of cervical nerve root compression with anterior cervical discectomy and fusion with a new titanium intervertebral disc. PATIENTS AND METHODS: 37 patients were examined prior to, as well as 4 days, 6 weeks, and 7 months after surgery. Lateral view X-rays and functional imaging were used to evaluate posture and mobility of the cervical spine, the position of the implants, and the reactions of adjacent bone structures. RESULTS: Implantation of the titanium disc led to post-operative distraction of the intervertebral space and slight lordosis. Within the first 6 months a slight loss of distraction and re-kyphosis due to impression of the implants into the vertebral end-plates were found in all patients. We noted partial infractions into the vertebral end-plates in 10/42 segments and slight mobility of the implants in 14/42 segments. Both groups of patients showed reactive spondylosis and local symptoms due to loosening of the implants. The pain subsided after onset of bone bridging and stable fixation of the loosened discs. CONCLUSIONS: The titanium intervertebral disc provides initial distraction of the fusion segments with partial recurrence of kyphosis during the subsequent course. Loosening of the implants with local symptoms can be evaluated with follow-up X-rays and functional imaging.

Adult↗
PubMed1999

[Rotational digital subtraction angiography of carotid bifurcation stenosis].

PURPOSE: A prospective study was designed to evaluate, whether multiplanar imaging with rotational digital subtraction angiography (R-DSA) could improve assessment of carotid artery bifurcation stenosis. PATIENTS AND METHODS: 45 patients with suspected stenosis of the ICA were examined with DSA in standard projections (0 degree-(45 degrees)-90 degrees) and additional R-DSA of each ICA from 0-90 degrees in 10 degrees steps. We compared imaging quality and degree of stenosis as well as exposure of the patients to radiation and contrast media. RESULTS: 79/82 R-DSA (96%) were suitable for evaluation of stenosis, 58/82 (70%) matched the quality standard of single projection DSA. Specificity and sensitivity of the R-DSA to diagnose high grade ACI stenosis were 100% and 94%, respectively. 7/79 R-DSA revealed a higher and 3/79 a lower degree of stenosis than the corresponding DSA. Regarding the degree of stenosis there was no significant difference between the two modalities (p > 0.05), but R-DSA detected 4 stenoses greater than 60% that were estimated to be lower than 60% by DSA. Radiation dose for R-DSA was equivalent to one DSA run (170 cGycm2). The average amount of contrast media (25 ml) was slightly higher than for 2-3 single-projection DSA (19.8 ml). CONCLUSIONS: R-DSA provides high quality imaging of the carotid bifurcation with multiplanar projections facilitating exact grading of vessel stenosis. The number of cases (n = 2) is to small to judge the value of R-DSA as to (tandem-) stenosis of the distal ICA. Still, diagnostic value and low radiation exposure justify the use of R-DSA as additional series to standard protocols.

Adult↗
PubMed1998

MRI follow-up in a case of clinically diagnosed Creutzfeld-Jakob disease.

We report the case of a 75-year-old woman suffering from Creutzfeld-Jakob disease (CJD). As brain biopsy was refused, diagnosis had to be based on clinical examination, EEC and findings on cranial MRI. Over a 4-month period MRI examinations demonstrated progressive cortical atrophy and bilateral enhanced signal intensity on T2-weighted images of caudate nuclei and putamina indicating development of spongioform degeneration. As clinical course and the characteristic pattern of brain lesions corresponded to cases of neuropathologically confirmed CJD, we suggest that MRI should be considered a valuable diagnostic tool in clinical diagnosis of the disease.

Aged↗
PubMed1998

[The assessment of the morphological changes after ventral diskectomy by thin-section computed tomography].

PURPOSE: We examined the changes of the intervertebral body space, the morphology of bone cement interponates and vertebrae after cervical discectomy and ventral fusion with high resolution CT. MATERIALS AND METHODS: CT scans were performed on 25 patients preoperatively, one week and six months after cervical discectomy and ventral fusion. RESULTS: There was no change in the size of the interponates. During follow-up new ossifications were found in 18 of the patients, two of them with neurological deficits. While directly after surgery the sagittal spinal canal diameter was enlarged, six months later particularly the lateral width was found to be reduced. After surgery soft tissue already narrowed the spinal canal in similar shape as the former prolapse. CONCLUSION: We conclude that postoperative neurologic deficits can only be partially explained by the described structural changes, because similar findings were made in uncomplicated postoperative courses as well as in patients with deficits.

Adult↗