Biomedical subjects

S Trattnig

Publications and source records attributed to S Trattnig.

At least 73 records · Page 4Linked to original sources

PubMed1997

[Comparison of diagnostic sensitivity in meniscus diagnosis of MRI examinations with a 0.2 T low-field and a 1.5 T high field system].

The aim of this study was to evaluate the reliability of a low field strength MRI unit (0.2 T; Esaote, Biomedica) and a high field strength MRI unit (1.5 T; Siemens) in detecting meniscal lesions. Twenty patients were investigated on a 0.2-T low-field MRI unit and a 1.5-T high-field MRI unit for meniscal lesions. Evaluation was performed of four meniscal compartments (anterior and posterior medial and lateral meniscus), for a total of 80 observations. The reliability of diagnosis was ranked qualitatively on a three-point scale. Investigations of the high-field MRI unit revealed a meniscal tear in 6 patients and ruled out a tear in 14 patients. Evaluation of individual meniscal compartments revealed diagnosis with high confidence in 58 observations and with moderate confidence in 22 observations. Investigations of the low-field MRI unit revealed a meniscal tear in 5 patients and ruled out tears in 15 patients. Evaluation of individual meniscal compartments revealed diagnosis with high confidence in 39 observations, with moderate confidence in 38 observations, and with low confidence in 3 observations. The diagnosis in high- and low-field images was identical in 98.7% of cases; in one patient observations from the high-field unit changed the therapeutic management. Diagnostic reliability was significantly higher with high-field strength MR imaging. Low field strength MR imaging shows comparatively high diagnostic accuracy for meniscal lesions compared to high field strength imaging; however, we demonstrated a significantly higher confidence in diagnosis with high-field MR imaging.

Adult↗

PubMed1997

[MRI diagnosis of lesions of the anterior cruciate ligament--comparison of 1.0 Tesla and 0.2 Tesla. Initial results].

The purpose of our study was to compare the diagnostic performance of a 0.2-T MRI unit and a 1.0-T MRI unit in the evaluation of the anterior cruciate ligament in patients with clinically suspected lesions of this ligament. Twenty four patients with clinically suspected lesions of the anterior cruciate ligament underwent MRI of the knee on both 0.2-T and 1.0-T MRI units. Three independent observers evaluated the examinations for primary and secondary signs of a tear of the anterior cruciate ligament. Frequency of these signs was determined for both modalities, and observer agreement was assessed using the kappa statistic. Sixteen of 24 patients had signs of tears of the anterior cruciate ligament on the 1.0-T unit; the 0.2-T unit detected primary signs in 15/16 (93%) patients and secondary signs in 7/12 (43%) patients. In 8 patients the 1.0 T unit showed neither primary nor secondary signs for tears of the anterior cruciate ligament; in these patients the 0.2-T unit detected primary signs in 1/8 cases (12%), and secondary signs in 3/8 cases (37%). Observer agreement was very good for the 1.0-T unit and fair for the 0.2-T unit. There is no substantial difference between 1.0-T units and 0.2-T MRI units in the visualisation of primary signs of tears of the anterior cruciate ligament. In the visualisation of secondary signs, 1.0-T units are superior to 0.2-T units, and there is a surprisingly high rate of false-positive results with the 0.2-T unit. As to the reproducibility of the results, the 1.0-T unit is far superior to the 0.2-T unit.

Adult↗

PubMed1997

[MRI in radiologically occult scaphoid fractures. Initial experiences with 1.0 Tesla (whole body-middle field equipment) versus 0.2 Tesla (dedicated low-field equipment)].

The study was performed to determine the diagnostic value of different MR systems and field strengths in patients with occult scaphoid and wrist fractures. Twelve patients with clinical suspicion of a scaphoid fracture but normal plain radiographs were examined by MRI. A dedicated 0.2-T unit (Esaote) and a 1.0-T unit (NT10, Philips) were used. Coronal T1W-SE, STIR, and T2*W-GE sequences were obtained with both systems. Images were evaluated for a bone marrow abnormality, a trabecular or cortical fracture line, and were compared to the 6-week follow-up radiographs. Seven wrist fractures were found at 0.2 T and 1.0 T, proven in the follow-up radiographs. A bone marrow abnormality was present in all seven fractures on both systems. Trabecular and cortical fracture lines were visualized at 0.2 T in four cases and at 1.0 T in seven cases. Low-field MR imaging at 0.2 T and mid-field MR imaging at 1.0 T seem to be equivalent in the diagnosis of a fracture in radiographically occult scaphoid and wrist fractures. In the visualization of fracture details, important for therapeutic and prognostic considerations, 1.0 T seems to be superior.

Adolescent↗

PubMed1997

Intraoperative and early postoperative colour Doppler sonography after carotid artery reconstruction: follow-up of technical defects.

We studied 50 patients with intraoperative colour-coded Doppler sonography (CCDS) after carotid artery reconstruction. Technical defects could be detected in 19 cases (38 %): residual plaques in 9, flaps in 8 and strictures in 2. In 9 cases (18 %) the carotid endarterectomy was revised. One residual plaque and one residual stricture caused thrombosis at the operative site a few hours postoperatively. One of the patients with residual plaques developed a high-grade stenosis within the follow-up period. Of the patients with residual plaques two had a medium-grade stenosis at follow-up. Six flaps decreased in size or disappeared within 1 week after operation. No patient with a flap developed a stenosis within the follow-up period. Our findings seem to indicate that correction of intimal flaps less than 10 mm in size is not necessary.

Aged↗

PubMed1997

Progressive multifocal leukoencephalopathy in AIDS: initial and follow-up CT and MRI.

We sought to determine the value of follow-up CT and MRI in patients with acquired immuno-deficiency syndrome (AIDS) and progressive multifocal leukoencephalopathy (PML). We reviewed 50 CT and 19 MRI examinations performed in 21 biopsy- or autopsy-proven cases of PML; 17 patients had follow-up examinations (mean time 5.9 weeks). The radiological examinations were correlated with pathological findings at autopsy. On initial imaging studies, 73 lesions were found. On follow-up, the most striking feature was rapid progression in both size and number of the lesions (from a mean of 3.2 to 6.9 per patient). One third of the patients showed increasing mass effect. A central area suggesting necrosis, of variable size, was found in 12/16 patients. Autopsy revealed macroscopic necrotic changes in the lesions in 11/16 patients.

AIDS Dementia Complex↗

PubMed1997

Degenerative joint disease: cartilage or vascular disease?

The aetiology of degenerative joint disease is multifactorial, but one main cause is overloading (mechanical stress). While until recently it was well accepted that this represented primarily a disorder of cartilage with reactive subchondral changes, there is now some evidence that it might be primarily a subchondral problem with secondary changes in the articular cartilage. Early subchondral changes include redistribution of blood supply with marrow hypertension, oedema and probably micro-necrosis. These findings are very similar to those in avascular necrosis of bone and raise the question of a vascular aetiology. While these first reports need further proof, it seems clear that the articular cartilage and subchondral regions are one functional unit, in which the subchondral region is more stress sensitive. Recently described channels connecting these two regions strengthen this opinion. These new concepts are exciting and may make a major impact in the near future on the management of and research into degenerative joint disease.

Bone and Bones↗

PubMed1997

Imaging of avascular necrosis of bone.

The etiology of avascular necrosis (AVN) is multifactorial. Independent of its etiology and localization it shows typical pathologies and radiological images. In the early stages localized subchondral edema is characteristic. In 50 % of all cases accompanying joint effusion may be found. Due to necrosis of the cells of bone marrow and bone fibrovascular, reactions with hyperemia can be delineated. These reactions allow us to visualize necrosis indirectly. The best imaging methods are MRI and, to a lesser extent, bone scintigraphy. In later stages calcification as well as new bone formation and microfractures are typically demonstrated and visualized best with plain X-rays and CT. Why reparations in many cases, particularly in the hip, are incomplete and may stop in any stage is unknown. Over years clinically complete silent AVNs are not an uncommon finding. Prognosis depends on the localization and size of the AVN. The number of repair mechanisms is best outlined with contrast-enhanced MRI and return of fatty marrow.

Bone and Bones↗

PubMed1997

The course of the prevertebral segment of the vertebral artery: anatomy and clinical significance.

BACKGROUND: The so called "pretransverse or prevertebral segment" of the vertebral artery is defined from its origin at the subclavian artery to its entry into the respective transverse foramen. In surgery, angiography, and in all noninvasive procedures it is of great importance to know the exact details of the course and the origin of this segment of the vessel as well as in which percentages real abnormalities can be found. METHODS: The VI segment of the vertebral artery was investigated both in anatomic preparations and clinical studies. A total of 402 vertebral arteries were evaluated (70 anatomic preparations in different forms, 181 patients, 95 angiographies of the aortic arch, and 86 color coded doppler sonographies). RESULTS: A contorted course was found in 157 (39%) cases. The plane of tortuosities demonstrated by the respective vessels was found to be horizontal in 40 (44.9%) cases, sagittal in 30 (33.7%) cases, and frontal in 19 (21.4%) cases. In 51 (32.5%) cases the contorted pathway was on the right side, and in 106 (68%) cases, on the left. A hypoplasia was found in 16 (10%) cases--11 (4.8%) right and 5 (2.2%) left. We further differentiated the convexity lying either medially or laterally in the transverse or frontal plane, or oriented dorsally or ventral in the sagittal plane. The exact location of the origin of the artery on the circumference of the subclavian artery (47% cranial, 44% dorsal, 3% ventral, 6% caudal) and also the average values of length and diameter are described. No significant differences between tortuous and nontortuous vessels were found with respect to length and diameter. A real abnormality of the origin of the vertebral artery was found in 8 (3.5%) cases. CONCLUSIONS: The described morphologic variations and frequencies of the VI segment of the vertebral artery have clinical applications in a wide field of pathologies in that region. To know about these findings seems to be very important not only in diagnosis (angiography, color coded doppler sonography) but also in their surgical and endovascular treatment.

Aorta, Thoracic↗

PubMed1997

Occult fractures of the scaphoid. The diagnostic usefulness and indirect economic repercussions of radiography versus magnetic resonance scanning.

Scaphoid fractures that are not visible on initial radiographs are notoriously difficult to diagnose. This prospective study compared four-view plain radiography at an average of 14 days after injury, with high-definition macroradiography and magnetic resonance imaging at presentation. Initial magnetic resonance imaging was superior to repeat scaphoid radiography for the confirmation or exclusion of fractures as well as for the detection of associated wrist injuries. Macroradiography was unsuitable for screening for occult scaphoid fractures.

Adolescent↗

PubMed1997

Overuse of hyaline cartilage and imaging.

Traumatic injury to joints may involve articular cartilage alone or result in osteochondral fractures which may impair mechanical properties of articular cartilage. Injuries of articular cartilage alone with visible tissue disruption and osteochondral fractures are now visualized by MRI which is the only modality for direct non-invasive visualization of articular cartilage. Three-dimensional T1-weighted gradient-echo sequences with fat-suppression provide high accuracy in the detection of cartilage surface defects. Fast spin echo imaging with heavy T2-weighting demonstrates cartilage defects in the presence of joint effusion accurately too, but minimal slice thickness in 2D-imaging is limited. For correct staging of osteochondral fractures, which determines further therapy, intraarticular administration of contrast media may be necessary. Repetitive direct blunt trauma or high-energy joint loading can cause cartilage damage without visible tissue disruption. To demonstrate this early stage of chondral injury special techniques and agents are necessary. These include diffusion weighted imaging, measurements of magnetization transfer as a function of collagen concentration, proton density mapping to plot the distribution of water in hyaline cartilage and sodium imaging to visualize ions bound to proteoglycans or intraarticular application of Mangan selectively bound to proteoglycans. Although promising techniques, they are still experimental. With recent developments of repair of cartilage defects by cartilage grafts, osteochondral autografts and transplantation, MRI becomes the method of choice in the noninvasive evaluation of injured articular cartilage and follow-up studies.

Cartilage, Articular↗

PubMed1997

[Determination of cartilage thickness in the ankle joint. an MRT (1.5)-anatomical comparative study].

PURPOSE: The aim of this study was to evaluate the accuracy of MRI in the measurement of cartilage thickness of the ankle joint in comparison to pathologic and histologic specimens. PATIENTS AND METHODS: The ankle joints of four fresh cadaver feet were imaged on a 1.5T MR-unit in the coronal plane. Standard T1-weighted spin echo (SE) and a T1-weighted 3D-GE (FLASH-3D) sequence with fat saturation were applied. Following MR imaging, the talus was explanted and cut parallel to the MR images for macroscopic evaluation and histologic specimens were prepared. MRI measurements of the cartilage thickness of the talus were carried out in two ways: without and with consideration of a transition zone of intermediate signal intensity between hyperintense cartilage and hypointense cortical bone. The data were compared with the anatomic specimens as the gold standard expressing the difference as a percentage value. On histologic specimens thickness of deep calcified cartilage layer was measured. RESULTS: Measurements without the transition zone showed a mean underestimation of talus cartilage thickness of 46.8% (41.3-52.1) for T1-SE and 47.5% (43.1-52.1) for fat saturated FLASH-3D images. Considering the transition zone the mean values were 25.0% (23.1-26.2) and 14.1% (6.7-21.5). The histologic specimens showed a three-fold increase of thickness of deep calcified cartilage layer. CONCLUSIONS: Measurements of the cartilage layer of the ankle joint on MR images are only accurate if the transition zone (calcified cartilage layer) is considered and the optimal pulse sequence (FLASH-3D-fat-sat) is applied.

Aged↗

PubMed1997

[MRI of the regions of the inner ear and cerebellopontine angle using a 3D T2-weighted turbo spin-echo sequence. Comparison with conventional 2D T2-weighted turbo spin-echo sequences and T1-weighted spin-echo sequences].

PURPOSE: To assess the value of a three-dimensional (3D) T2-weighted turbo spin-echo sequence (3D T2-TSE) in comparison to conventional two-dimensional (2D) T2-weighted TSE and unenhanced and enhanced T1-weighted spin-echo sequences (SE) in imaging anatomic structures and pathologic changes of the inner ear and cerebellopontine angle. PATIENTS AND METHODS: The inner ear and cerebellopontine angle were investigated by MRI in three healthy volunteers and 18 patients performing a 2D T2-weighted turbo spin-echo sequence and a 3D T2-TSE in the axial plane. In the patient study, 2D T1-weighted SE sequences both before and after the i.v. injection of gadopentetate dimeglumine in both the axial and coronal plane were performed in addition. RESULTS: Only the 3D T2-TSE enabled an accurate imaging of the anatomic structures. In cases of pathology, the 3D T2-TSE provided additional information to the performed 2D sequences. The combination of the 3D T2-TSE with unenhanced and enhanced 2D T1-weighted SE enabled the most accurate diagnosis in cases of pathology. CONCLUSIONS: Accurate depiction of anatomic structures of the inner ear and cerebellopontine angle could be obtained by 3D T2-TSE only. The most accurate diagnosis in cases of pathology was provided by the combination of the 3D T2-TSE with unenhanced and enhanced 2D T1-weighted spin-echo sequences.

Adult↗

PubMed1997

Primary neuroendocrine (merkel cell) carcinoma of the anterior skull base.

A case of a primary neuroendocrine (Merkel cell) carcinoma arising in the anterior skull base involving the dura, both frontal lobes, and the paranasal sinuses is presented. The tumor was completely removed by an enlarged bifrontal transbasal approach. The neuropathological, immunohistological, and electron microscopical investigation revealed all characteristics of a Merkel cell carcinoma, normally presenting as a skin carcinoma of the head and neck. The history, treatment, neuropathology, and possible explanation for this rare manifestation are discussed.

Case Reports↗

PubMed1997

MR-guided joint puncture and real-time MR-assisted contrast media application.

OBJECTIVE: To develop, in MR arthrography of the shoulder joint, an MR-guided technique for localizing the needle puncture and confirming the intracapsular needle-tip position by visualization of the contrast media inflow. MATERIAL AND METHODS: Three unfixed human shoulder specimens were examined on a 1.0 T MR unit. On the basis of MR-compatible markers, the optimal entrance point for puncturing the joint was determined. The precise localization of the needle tip (MR-compatible 0.7-mm needle) in the shoulder joint was determined with rapid localizer GRE sequences in 2 orthogonal planes. To confirm the intracapsular position of the needle tip, diluted Gd-DTPA was applied via a long connecting tube and contrast medium inflow into the joint space was controlled on an LCD screen in real-time MR imaging (local-look technique). RESULTS: MR-compatible markers on the skin allowed the rapid determination of the optimal entrance point for needle puncture. An adequate localization of the intra-articular needle-tip position was possible in all specimens although significant artifacts were present on rapid localizer GRE sequences which resulted in an increase in the apparent width of the needle shaft. Real-time MR imaging of the contrast medium inflow was made possible by the local-look technique and LCD screen on the MR unit and this allowed confirmation of the intracapsular position. CONCLUSION: In MR arthrography of the shoulder, an MR-guided technique in conjunction with the LCD screen and real-time MR imaging would seem to be a practical alternative to conventional fluoroscopic guidance.

Artifacts↗

PubMed1997

MR imaging of meniscal subluxation in the knee.

PURPOSE: The aim of this study was to establish diagnostic criteria for meniscal subluxation, and to determine whether there was any connection between meniscal subluxation and other common meniscal and knee-joint abnormalities. MATERIAL AND METHODS: The normal position of the meniscal body was assessed in 10 asymptomatic volunteers. MR signs of meniscal subluxation were evaluated retrospectively in 60 symptomatic patients with pain in the knee, impaired mobility, and/or joint swelling who had no clear diagnosis after the evaluation of case history, clinical examination, and radiography. The criterion for subluxation of the meniscus was defined as a distance of > or = 3 mm between the peripheral border of the meniscus and the edge of the tibial plateau. RESULTS: In the volunteers, the mean distance from the medial meniscus to the edge of the tibial plateau was 0.07 mm, and that from the lateral meniscus was 0 mm. In 55 symptomatic patients without meniscal subluxation, the mean distance from the meniscus to the edge of the tibial plateau was 0.27 mm. Five patients (8%) had evidence of meniscal subluxation, 4 in the medial meniscus and one in the lateral meniscus. The most commonly associated knee abnormality was joint effusion in 5 knees and osteoarthritis in 2 knees. CONCLUSION: Meniscal subluxation was not a rare finding with MR imaging in patients with painful knees. Meniscal subluxation was associated with other knee abnormalities such as joint effusion or osteoarthritis.

Adolescent↗

PubMed1997

GRASE: ultra-fast turbo gradient spin-echo sequence. A new approach to fast MR imaging of the musculoskeletal system.

PURPOSE: Ultra-fast gradient and spin-echo (GRASE) imaging is a hybrid of turbo spin-echo (TSE) and echo-planar imaging (EPI). One scan consists of several spin echoes (SEs) (turbo factor, TF), each of which consists of a number of gradient echoes (EPI factor, EF). The aim of our study was to evaluate different combinations of TF and EF in GRASE imaging and to test its usefulness in musculoskeletal imaging. MATERIAL AND METHODS: On a 1.0 T MR unit, 11 GRASE sequences with different combinations of TF and EF (TR/TE 2150/120 ms) were evaluated in phantom studies with respect to signal-to-noise (S/N) ratio, nonuniformity of images, and geometrical distortion. From this study, the optimal GRASE-sequence was applied to 25 patients with different joint pathologies and compared to a T2-weighted TSE sequence (TR/TE 2855/130 ms). Lesion visualization, conspicuity, overall image quality, and artifacts were qualitatively analyzed by two observers independently of each other. RESULTS: With respect to S/N ratio, signal nonuniformity, and geometrical distortion, the GRASE sequence with TF/EF 7/3 (S/N 47; signal nonuniformity 11.7%; distortion 1 pixel) proved to be superior to the other GRASE sequences within a scanning time of less than 120 s. In a clinical study, the GRASE sequence proved superior to T2-weighted TSE (without fat suppression) in the visualization of bone-marrow and soft-tissue lesions (p < 0.001) and ligamentous injuries, although the image quality was inferior.

Artifacts↗

PubMed1997

Differentiation of benign and malignant breast lesions: MR imaging versus Tc-99m sestamibi scintimammography.

PURPOSE: To compare the accuracies of magnetic resonance (MR) imaging and scintimammography in differentiating benign from malignant breast lesions. MATERIALS AND METHODS: MR imaging was performed in 66 women with 75 lesions during intravenous administration of gadopentetate dimeglumine. Planar and single photon emission computed tomographic (SPECT) scintimammography were performed (with 740 MBq technetium-99m sestamibi administered intravenously) in all 66 patients with 75 lesions and in 64 patients with 73 lesions, respectively. MR imaging and scintimammographic studies were independently evaluated by using signal intensity measurements versus time or focal tracer uptake to differentiate benign from malignant lesions. Histopathologic proof was obtained in 63 lesions. Twelve lesions were monitored with follow-up. RESULTS: MR imaging was false-negative in one and false-positive in nine lesions. Planar scintimammography was false-negative in 10 and false-positive in six lesions. SPECT scintimammography was false-negative in four and false-positive in 10 lesions. Sensitivities and specificities for malignancy were, respectively, 96% and 82% for MR imaging, 62% and 88% for planar scintimammography, and 83% and 80% for SPECT scintimammography. CONCLUSION: Both MR imaging and scintimammography are useful in the evaluation of breast cancer. MR imaging is more sensitive and as specific as scintimammography.

Adult↗

PubMed1997

Radiographically occult scaphoid fractures: value of MR imaging in detection.

PURPOSE: To evaluate the diagnostic value of magnetic resonance (MR) imaging in patients with clinical suspicion of scaphoid fractures and normal initial plain radiographs. MATERIALS AND METHODS: MR imaging was performed within 7 days after trauma in 42 patients with clinical suspicion of scaphoid fractures and normal plain radiographs. T1-weighted spin-echo, T2*-weighted gradient-echo, and short inversion time inversion-recovery (STIR) sequences were performed. MR images were evaluated independently by two radiologists. Six-week follow-up radiographs were used as a standard to diagnose fractures. RESULTS: MR imaging depicted occult fractures of the scaphoid bone in 14 patients (33%), the capitate bone in four (10%), the trapezium in one (2%), and the distal radius in two (5%). All wrist fractures were detected with a combination of STIR and T1-weighted spin-echo sequences. The sensitivity and specificity for detection of radiographically occult fractures of the wrist were 100% each for the first and 95% and 100%, respectively, for the second radiologist with an almost perfect interobserver agreement (K = 0.953). CONCLUSION: MR imaging has a high sensitivity for detection of fractures of the scaphoid bone and wrist not evident on plain radiographs and may enable early diagnosis and treatment.

Adolescent↗