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C Muhle

Publications and source records attributed to C Muhle.

At least 55 records · Page 3Linked to original sources
PubMed1997

[Comparison of T2-weighted turbo spin-echo and ultrafast HASTE sequence in the diagnosis of cervical myelopathies and spinal stenoses and static and kinematic MRT of the spine].

PURPOSE: The purpose of this study was to compare HASTE-sequence with T2-weighted TSE-sequence in the detection of cervical myelopathy and cervical spinal stenosis in kinematic MRI. METHODS: 24 patients with degenerative disease of the cervical spine were studied. Images were evaluated according to the following criteria: artifacts, delineation of the vertebra, disks and degenerative changes, grade of spinal stenosis (grade 0-3) and evaluation of the cervical spinal cord. RESULTS: Due to image blurring and artifacts, evaluation and delineation of the cervical spine was possible in all cases in the T2-weighted TSE-sequence, but only in 23 of 24 patients using HASTE-sequence. Differentiation between osteophytes and disks was obtained in most cases (23/24) in the T2-weighted TSE-sequence but none in the HASTE-sequence. Cervical myelopathy was observed in 4 patients in T2-weighted TSE images but only in two cases using HASTE-sequence. Compared to T2-weighted TSE-sequence spinal canal stenosis was underestimated using HASTE-sequence. CONCLUSION: T2-TSE-sequence is superior to HASTE-sequence in the delineation of anatomical structures of the cervical spine, the grading of cervical spinal stenosis and the evaluation of cervical myelopathy.

Adult↗
PubMed1997

Kinematic MR imaging of the ankle--initial results with ultra-fast sequence imaging.

PURPOSE: In order to evaluate the advantages of ultra-fast MR sequences, kinematic MR imaging studies were performed in 4 patients with osteochondritis dissecans of the talus and in 12 healthy volunteers. MATERIAL AND METHODS: The patients and volunteers were placed inside a custom-made positioning device. Sagittal ultra-fast T2-weighted turbo gradient-echo sequences and HASTE sequences were obtained during active joint motion from dorsiflexion to plantar flexion. Eight sagittal slices were scanned separately to cover this ankle motion. In each slice, 8 to 10 images were obtained in 12-s or 18-s periods. RESULTS: Adequate image quality for analyzing the normal kinematics of the ankle was obtained in all subjects. At surgery, the osteochondral fragment was found to be mobile in 3 of the 4 of the patients. In none of these cases was fragment mobility observed on kinematic MR imaging. No motion of the fragments was observed in the fourth patient, neither at surgery nor on kinematic MR imaging. CONCLUSION: Ultra-fast MR imaging sequences made it possible to produce kinematic MR imaging studies of active joint motion. The positioning device was useful for guiding joint motion in patients and for obtaining adequate image quality.

Adult↗
PubMed1997

The total entropy for evaluating 31P-magnetic resonance spectra of the liver in healthy volunteers and patients with metastases.

RATIONALE AND OBJECTIVES: The authors describe the clinical status of liver tissue with only a single numerical quantity (total entropy) derived from spectroscopic data of 31P-magnetic resonance (MR) spectra. METHODS: Twenty-four patients with liver metastases and 20 volunteers were investigated with image-guided volume selective 31P-MR spectroscopy on a 1.5-T whole body scanner. From each in vivo 31P-MR spectrum, the ratios of phosphomonoester (PME)/beta-adenosine triphosphate (ATP), inorganic phosphate (Pi)/beta-ATP and phosphodiester (PDE)/ beta-ATP and the total entropy (H*) were calculated. Mean values and standard deviations were determined and significance of the differences were tested with Student's t test. RESULTS: For patients, the H* = 4.7 +/- 4.3, PME/beta-ATP 0.72 +/- 0.28, Pi/beta-ATP = 1.00 +/- 0.39, PDE/beta-ATP = 1.68 +/- 0.59. For the volunteers, H* = 7.6 +/- 2.5, PME/beta-ATP = 0.39 +/- 0.15, Pi/beta-ATP = 0.90 +/- 0.19, PDE/beta-ATP = 1.25 +/- 0.28. The total entropy of patients' spectra showed significantly lower values compared with those of volunteers. PME/beta-ATP and PDE/beta-ATP of the patients increased and differed significantly from volunteer data. CONCLUSIONS: It was demonstrated that the results of in vivo 31P-MR spectroscopy may be described with a single criterion by means of the total entropy.

Adenosine Triphosphate↗
PubMed1996

Influence of different fasting periods on P-31-MR-spectroscopy of the liver in normals and patients with liver metastases.

The purpose of this study was to determine the influence of different fasting periods on the in vivo P-31-MR spectroscopy of the healthy liver and patients with liver metastases. Image-guided localized P-31-MRS was performed in 24 patients with liver metastases and in 20 healthy volunteers. The spectra were obtained with a whole body scanner operating at 1.5 T using a surface coil. The P-31-MRS was performed after a fasting period of 3-5 h (group 1) and after overnight fasting (group 2). The PME/beta-NTP, PDE/beta-NTP and Pi/beta-NTP were calculated from P-31-MR spectra and were compared in relation to the nutrition status of the volunteers and patients. The PME/beta-NTP and PDE/beta-NTP were significantly increased in spectra of patients with metastases. There were no significant changes in the ratios of phosphorus metabolites in healthy liver tissue or in liver metastases after a fasting period of 3-5 h as compared with overnight fasting.

Adult↗
PubMed1996

[Preoperative differential diagnosis of cystic adnexal tumors: double-contrast MRT].

PURPOSE: Preoperative assessment of adnexal lesions as benign or malignant by MRI with gastrointestinal and intravenous contrast. METHODS: 46 patients with benign (n = 42) and malignant (n = 4) cystic adnexal tumours underwent MRI of the pelvis. Transaxial and coronal images were acquired using conventional T1- and T2-weighted SE-sequences after oral administration of superparamagnetic iron oxide particles (Ferristene). Additional T1-weighted SE-images were obtained immediately following gadodiamide (Gd DTPA-BMA) injection. RESULTS: MRI correctly classified the four malignant lesions, whereas nine histologically benign lesions were misdiagnosed as malignant. Intravenous contrast yielded a superior delineation of intratumor architecture. CONCLUSION: Due to exclusion of solid structures. MRI with oral and i.v. contrast enables to dismiss suspected malignity in cystic adnexal lesions. Because of the non-specificity of the macroscopic criteria of dignity, the MR diagnosis "malignity" is of limited value.

Adenocarcinoma↗
PubMed1996

Effect of intraarticular pressure on patellar position. Computed tomography study in cadaveric specimens.

RATIONALE AND OBJECTIVES: The purpose of the study was to evaluate the effect of articular fluid distention on patellar position at different degrees of knee angulation. METHODS: Patellar position in 10 cadaveric knee specimens was determined with 30, 100, and 200 mm Hg joint distention at 45, 20, and 5 degrees of knee flexion using computed tomography. Patellar tilting and lateromedial and anteroposterior displacement of the patellar position were analyzed. RESULTS: Lateral tilting increased with greater articular distention and decreasing knee flexion. At 5 degrees of flexion and 200 mm Hg of distention, change in lateral tilting ranged from -7 to +5 degrees. At 45 degrees of flexion and increased distention, the patellar shift ranged from 6 mm medialization to 1 mm lateralization for 200 mm Hg, but the patellar position was more variable at 5 degrees of flexion with increasing intraarticular pressure (range 7 mm medialization to 8 mm lateralization). With increasing articular pressure the patellae were increasingly displaced anteriorly with the most pressure-dependent changes at 45 and 20 degrees of knee flexion. CONCLUSIONS: Fluid distentions of the knee joint have unpredictable and varying effects on the patellar position and vary considerably among persons. When judging patellar position during arthroscopy and in patients with large joint effusions, the arthroscopist and radiologist should be aware of these effects.

Aged↗
PubMed1995

Cine MR imaging before and after realignment surgery for patellar maltracking -- comparison with axial radiographs.

OBJECTIVE: Comparison of motion-triggered cine magnetic resonance (MR) imaging and conventional radiographs for the assessment of operative results of patellar realignment. SUBJECTS AND METHODS: Fifteen patients with recurrent patellar dislocation or patellar subluxation were evaluated with conventional axial radiographs before and after realignment surgery by measuring the congruence angle (CA), lateral patellofemoral angle (LPFA), and lateral displacement (d). In eight patients the patellofemoral joint was additionally evaluated pre- and postoperatively with motion-triggered cine MR imaging by determining the bisect offset (BSO), lateral patellar displacement (LPD), and patellar tilt angle (PTA). RESULTS AND CONCLUSIONS: Significant differences between the pre- and postoperative measurements were found for all MR imaging parameters (BSO, LPD, PTA: p<0.01) but not for the conventional X-ray parameters (CA: p = 0.70, LPFA: p = 0.56; d: p = 0.04). Motion-triggered cine MR imaging was superior to conventional tangential radiographs for assessing the effectiveness of patellar realignment surgery.

Adolescent↗
PubMed1995

[Kinematic MRI in degenerative cervical spine changes].

AIM: To evaluate functional stenosis of the cervical spine, kinematic MRI was performed in 23 healthy volunteers and 23 patients with degenerative disease. MATERIAL AND METHOD: Kinematic MRI of the cervical spine was done from 50 degrees of inclination to 30 degrees of reclination. Depending on the maximum inclination and reclination the range of motion was divided into 9 equal angle positions. At each angle position sagittal T2* weighted gradient echo sequences were performed. RESULTS: In relation to the neutral position a physiological narrowing of the ventral epidural space was seen in healthy volunteers at inclination (50 degrees) in up to 50% and respectively widening at reclination (30 degrees) in up to 10%. An increase of spinal canal stenosis or even spinal cord compression was seen at inclination in 5 patients (22%) and in 15 patients (65%) at reclination. No change of spinal canal stenosis was found in three patients (13%). CONCLUSION: In patients with degenerative disease of the cervical spine kinematic MRI demonstrated in some patients functional spinal canal stenosis with myelon compression which was not seen in standard MRI. Therefore kinematic MR imaging can be recommended as a complementary examination in the early detection of functional myelon compression and in planning the further therapeutic work-up.

Adult↗
PubMed1995

In vivo P-31-MR-spectroscopy of focal hepatic lesions. Effectiveness of tumor detection in clinical practice and experimental studies of surface coil characteristics and localization technique.

RATIONALE AND OBJECTIVES: The influence of partial tumor sampling in a volume of interest (VOI) on the ratios of phosphorus metabolites was examined by localized phosphorus magnetic resonance spectroscopy (P-31-MRS). Experiments were performed to investigate the characteristics of the surface coil used and precession of spatial localization. METHODS: A total of 24 patients with liver metastases and 20 volunteers were studied by P-31-MRS. Patients were divided in two groups: VOI < 50% (n = 8) and VOI > 50% (n = 16) occupied by tumor. For evaluation of the surface coil and localization method (image selected in vivo spectroscopy), phantom studies were performed. RESULTS: Superficial focal liver tumors were detectable with a surface coil at a distance within the coil radius. The image selected in vivo spectroscopy permitted the study of phosphorus metabolism in a defined VOI, phosphomonoester/beta-adenosine triphosphate and phosphodiester/beta-adenosine triphosphate were elevated significantly in spectra of both patient groups. CONCLUSIONS: Detection of small tumor volumes within a VOI filled by less than 50% of the tumor is possible, with results statistically different from that in normal volunteers.

Adult↗
PubMed1995

Application of the maximum entropy method for evaluating phosphorus-31-magnetic resonance spectra in patients with liver metastases.

RATIONALE AND OBJECTIVES: The clinical feasibility and application of the maximum entropy method for data analysis from in vivo phosphorus-31-magnetic resonance (P-31-MR) spectra of the liver were determined. METHODS: Image-guided localized P-31-MR spectroscopy was performed in 24 patients with liver metastases and in 20 healthy volunteers. The spectra were obtained with a whole body scanner operating at 1.5 T using a surface coil. Phosphomonoester/beta-adenosine triphosphate (ATP), phosphodiester/beta-ATP, and inorganic phosphate/beta-ATP were calculated from the maximum entropy method-spectra and from spectra evaluated with standard data processing (Fourier transformation spectra). RESULTS: Phosphomonoester/beta-ATP and phosphodiester/beta-ATP were increased significantly with both methods in patients' spectra. Maximum entropy method spectra showed a distinct pattern with low noise. It was easier to determine peak borders and to attach resonances to the different metabolites using this method. CONCLUSIONS: Maximum entropy method is an alternative method for evaluation and quantification of P-31-MR spectra data and is preferred to standard data processing with Fourier transformation in cases of reduced signal-to-noise ratio of spectra.

Aged↗
PubMed1995

[Functional MRI of the femoropatellar joint].

Conventional X-ray examinations of the patellofemoral joint in 30 degrees, 60 degrees and 90 degrees of knee flexion demonstrate the position of the patella. On the other hand, they have been shown to be insufficient for the diagnosis of patellofemoral maltracking in the critical range between 30 degrees of flexion and full extension. Motion-triggered and ultrafast MRI offer new possibilities for functional diagnosis of the patello-femoral joint under active knee motion. Functional MRI of the patellofemoral joint is suggested as an alternative to arthroscopy, particularly in patients with anterior knee pain or suspected patellar maltracking.

Arthroscopy↗
PubMed1994

[High-resolution CT (HRCT) of the lung in Wegener's granulomatosis].

HRCT of the lung and plain chest X-ray were performed to reveal pulmonary manifestation in primary diagnostics or reevaluation of 35 patients with Wegener's granulomatosis. Pleural and parenchymal pathology was detected in chest X-ray of 20 (57%) and in HRCT of 30 (85.7%) patients. Granulomas with and without cavitations and with smooth or spiculated margins were deemed pathognomonic. Nonspecific findings were infiltrates, thickened interlobular septae and fibrotic changes of parenchyma and pleura. Ground glass opacities, traction bronchiectasis and small cysts were only visible on HRCT. As expected HRCT proved to be more sensitive in detecting subtle lung alterations than plain film chest X-ray. It helps to differentiate acute inflammatory and thus potentially curable processes from chronic fibrotic changes in Wegener's granulomatosis.

Adult↗
PubMed1994

Evaluation of patellar tracking in patients with suspected patellar malalignment: cine MR imaging vs arthroscopy.

OBJECTIVE: The purpose of this study was to compare results of motion-triggered cine MR imaging of active extension of the knee with arthroscopic findings in cases of suspected femoropatellar malalignment. SUBJECTS AND METHODS: Twenty patients with clinically proved or suspected patellar subluxation or dislocation were examined prospectively with motion-triggered cine MR imaging to analyze patellar tracking from 30 degrees of flexion to full extension during active extension of the knee. The patellar tracking pattern was evaluated by measuring the following: bisect offset and lateral patellar displacement to assess lateralization of the patella and the patellar tilt angle to assess tilting of patella. The slopes of the linear regression lines of the MR findings vs the knee angle position, representing the patellar tracking, and the position of the patella at 30 degrees and 0 degrees of flexion were correlated with a semiquantitative arthroscopic classification of patellar tracking that had four categories ranging from normal to highly abnormal. RESULTS: The results showed a significant correlation between the semiquantitative arthroscopic findings of patellar tracking and the slopes of the linear regression lines of the bisect offset, lateral patellar displacement, and patellar tilt angle, as measured with cine MR imaging (p < .01). The arthroscopic findings also correlated significantly with the position of the patella when the knee was extended (p < .01), but not with the knee flexed 30 degrees. CONCLUSION: We conclude that motion-triggered cine MR imaging of active extension of the knee enables the dynamic evaluation of patellar bracing and is therefore suitable for noninvasive analysis of patellar tracking.

Adult↗
PubMed1994

[Magnetic resonance tomography and computerized tomography of Wegener's granulomatosis of the orbits].

Of a total of 121 patients with histological proven Wegener's Granulomatosis, orbital involvement occurred in 12 cases. Eight of them underwent magnetic resonance imaging (MRI) of the head and brain, in 2 cases computed tomography (CT) was additionally performed. With MRI orbital granulomas had a low signal intensity in T1- and T2-weighted spin-echo sequences. After i.v. contrast medium administration an inhomogeneous enhancement was found. Because of the multiple imaging planes and high soft tissue contrast, orbital granulomas were better delineate with regard to the intraorbital muscles and the optic nerve using MRI than with CT. Osseous destruction and sclerosis of the orbital walls were demonstrated more effectively using CT. MRI and CT are thus complementary for diagnosing and staging, of orbital granulomas and periorbital involvement in Wegener's Granulomatosis.

Adult↗
PubMed1993

MRI of the head in Wegener's granulomatosis.

MRI of the head was performed in 25 patients suffering from Wegener's granulomatosis. 23 patients showed mucosal inflammation in the nasal cavity and in the paranasal sinuses, 10 patients had granulomas in the paranasal sinuses and in the orbits, 7 patients had cerebral lesions, 3 patients had submucosal hemorrhages in the paranasal sinuses and 3 patients showed bone erosions or destructions in the facial skeleton, which was visible only by CT.

Bone and Bones↗
PubMed1993

Patellar tracking patterns during active and passive knee extension: evaluation with motion-triggered cine MR imaging.

To evaluate the critical range of the patellofemoral joint motion from 30 degrees of knee flexion to full extension, motion-triggered cine magnetic resonance (MR) imaging was performed during active extension in 13 patients with confirmed patellar maltracking and 15 healthy subjects. Cine MR images were compared with static MR images obtained during incremental extension of the knee joint. To evaluate the patellar tracking pattern, the same imaging parameters (patellar tilt angle, bisect offset, and lateral patellar displacement) and section locations were used in the static and motion-triggered studies. Statistically significant differences between the passive and active knee motions were found in all three parameters in the group of patients and in the bisect offset in the control group. The comparison between patients and healthy subjects yielded statistically significant differences for all parameters in actively extended knees but not in passively extended knees. The results demonstrate the importance of dynamic patellar motion studies for diagnosis of patello-femoral maltracking.

Adolescent↗
PubMed1992

Motion-triggered cine MR imaging of active joint movement.

MRI cine studies of active physiological joint movement can provide additional functional information as a supplement to standard examinations. With the ankle joint as an example, it is shown that it is possible to measure kinematic MRI presentations of active joint movement. A pneumatic pressure transducer, a respiratory monitor, and an active differentiator transformed the skin muscle shifting of periodically performed joint movement to a pseudo-ECG, which finally triggered the MRI scanner as in cardiac cine MR imaging.

Ankle Joint↗