Biomedical subjects

C Muhle

Publications and source records attributed to C Muhle.

At least 37 records · Page 2Linked to original sources

PubMed1999

Kinematic CT and MR imaging of the patellofemoral joint.

Anterior knee pain is a frequently encountered orthopedic symptom and is often associated with patellofemoral malalignment, which may cause chondromalacia of the patella. The difficulty in determining the patellar position between 0 degrees and 30 degrees of knee flexion with a conventional axial radiographic examination is well known. The introduction of computed tomography (CT) and magnetic resonance (MR) imaging for the diagnosis of knee joint abnormalities has enabled assessment of the patellar position in this critical range. More recently, emphasis has been placed on dynamic visualization of patellar motion to detect an abnormal tracking pattern. The important influence of the quadriceps muscle on the patellar tracking pattern is well known and has been examined during active knee extension by the use of ultrafast CT, and motion-triggered and ultrafast MR imaging. This article provides an overview of the current status of kinematic CT and MR imaging in the diagnosis of patellofemoral alignment, its clinical implications, and future directions.

Arthralgia↗

PubMed1999

Transverse ligament and its effect on meniscal motion. Correlation of kinematic MR imaging and anatomic sections.

RATIONALE AND OBJECTIVES: To evaluate the effect of the transverse ligament on translation of the menisci. METHODS: Six cadaveric knees were examined by MR imaging inside a positioning device before and after transecting the transverse ligament. The knees were examined at various positions: extension, 30 degrees of flexion, 60 degrees of flexion, and full flexion. Sagittal T1-weighted spin-echo images were generated at each knee position and evaluated for statistical differences with regard to anterior-posterior meniscal excursion. RESULTS: Statistically significant differences in meniscal excursion were found before and after transsecting the transverse ligament for anterior-posterior meniscal motion of the anterior horn of the medial meniscus at 30 degrees of knee flexion. No such significant differences were found, however, at 60 degrees of flexion and full flexion in anterior-posterior meniscal excursion of the anterior or posterior horn of either meniscus before and after transsecting the transverse ligament. CONCLUSIONS: The transverse ligament has a restricting effect on anterior-posterior excursion of the anterior horn of the medial meniscus at lower degrees of knee flexion.

Aged↗

PubMed1999

Iliotibial band friction syndrome: MR imaging findings in 16 patients and MR arthrographic study of six cadaveric knees.

PURPOSE: To define magnetic resonance (MR) imaging findings in patients with the iliotibial band friction syndrome (ITBFS) and to correlate these findings with anatomic features defined at magnetic resonance (MR) arthrography in cadavers. MATERIALS AND METHODS: The anatomic relationship of the iliotibial tract (ITT) to the lateral recesses of the knee joint and the lateral femoral epicondyle was investigated with MR arthrography at full extension and at 30 degrees and 60 degrees of knee flexion in six cadaveric knees. Seventeen MR imaging studies in 16 patients with ITBFS were evaluated. RESULTS: In the cadaveric study, no interference of the lateral synovial recess with the lateral femoral epicondyle at full extension and at 30 degrees and 60 degrees of knee flexion was observed. In all specimens, correlation of MR images with macroscopic and microscopic sections revealed no primary bursa between the lateral femoral epicondyle and the ITT. In clinical studies, MR imaging findings of poorly defined signal intensity abnormalities or circumscribed fluid collections were located in a compartmentlike space confined laterally by the ITT and medially by the meniscocapsular junction, the lateral collateral ligament, and the lateral femoral epicondyle. CONCLUSION: MR imaging accurately depicts the compartmentlike distribution of signal intensity abnormalities in patients with ITBFS.

Adolescent↗

PubMed1999

Bicipitoradial bursitis: MR imaging findings in eight patients and anatomic data from contrast material opacification of bursae followed by routine radiography and MR imaging in cadavers.

PURPOSE: To use radiography and magnetic resonance (MR) imaging after contrast material opacification of the bursae in cadaveric specimens to demonstrate the anatomy of the bicipitoradial bursa and to report MR imaging findings in patients with bicipitoradial bursitis. MATERIALS AND METHODS: Bicipitoradial bursa in eight cadaveric elbows were injected with a solution containing gadodiamide, iodinated contrast agent, and gelatin. Radiographs and MR images were obtained in each specimen, with both supination and pronation of the forearm. The morphology and relationships of the bursa were studied. Anatomic sections subsequently were obtained. MR imaging studies in eight patients with bicipitoradial bursitis were also evaluated. RESULTS: The bicipitoradial bursa revealed a smooth outline and a wide base along the superficial aspect of the radius. The mean volume of contrast material that could be injected before extravasation was 4 mL. The mean size of the bursa was 1.8 x 2.5 cm. The bicipitoradial bursa enveloped the biceps tendon, with internal septation seen in two cases. Displacement of the superficial branch of the radial nerve by the bursa was found in two specimens. Communication between the bicipitoradial bursa and elbow joint was not observed. In patients, MR imaging demonstrated fluid collections in the bicipitoradial bursa in all cases, with compression of branches of the radial nerve in two cases. CONCLUSION: The anatomy of the bicipitoradial bursa is demonstrated with radiography and MR imaging of bursae. MR imaging allows accurate diagnosis of bicipitoradial bursitis and its effects on adjacent structures.

Adult↗

PubMed1999

Ligaments and tendons of the ankle. Evaluation with low-field (0.2 T) MR imaging.

PURPOSE: To investigate the value of MR imaging using a low-field imaging unit (0.2 T) for the evaluation of ligaments and tendons of the ankle. MATERIAL AND METHODS: Twelve ankle specimens were studied using low-field MR imaging (0.2 T). The Achilles tendon, the tibialis posterior tendon, and the lateral collateral ligaments were evaluated for the presence of degenerative changes and partial and complete tears. Visibility and overall image quality were analyzed by qualitative evaluation. RESULTS: Low-field MR images of the 24 tendons were interpreted as normal in 11 cases, showing degenerative changes in 9 cases and a partial tear in 1 case. Visualization was regarded as not sufficient for a diagnosis in 3 cases. Of the 36 ligaments, 14 were regarded as normal while degenerative changes were seen in 5 cases and a tear in 2 cases. In 13 cases, no diagnosis could be established, and in 2 cases only a probable diagnosis was established. The best overall quality was obtained with the use of T1 spin-echo (680/20/4) and T2 multi-echo (3000/40/1) images. CONCLUSION: Optimized protocols for examination of the ankle using low-field MR imaging may allow evaluation of the Achilles and tibialis posterior tendons, but these protocols may not be as useful for diagnosing ligamentous changes.

Achilles Tendon↗

PubMed1999

Kinematic MR imaging in surgical management of cervical disc disease, spondylosis and spondylotic myelopathy.

PURPOSE: To estimate the clinical value and influence of kinematic MR imaging in patients with degenerative diseases of the cervical spine. MATERIAL AND METHODS: Eighty-one patients were examined with a 1.5 T whole body magnet using a positioning device. Cervical disc disease was classified according to clinical and radiographic findings into 4 stages: stage I=cervical disc disease (n=13); stage II=spondylosis (n=42); stage III=spondylosis with restricted motion (n=11); and stage IV=cervical spondylotic myelopathy (n=15). Findings on kinematic MR images were compared to those on flexion and extension radiographs, myelography, CT-myelography and static MR imaging. Furthermore, the influence of kinematic MR imaging on surgical management and intra-operative patient positioning was determined. RESULTS: Additional information obtained by kinematic MR imaging changed the therapeutic management in 7 of 11 (64%) patients with stage III disease, and in 13 of 15 (87%) patients with stage IV disease. Instead of an anterior approach, a posterior surgical approach was chosen in 3 of 11 patients (27%) with stage III disease and in 6 of 15 patients (40%) with stage IV disease. Hyperextension of the neck was avoided intra-operatively in 4 patients (27%) with cervical spondylotic myelopathy, and in 1 patient with stage II (2%) and in 1 patient with stage III (9%) disease. Kinematic MR imaging provided additional information in all patients with stages III and IV disease except in 1 patient with stage III disease, when compared to flexion and extension radiographs, myelography, CT-myelography and static MR examination. CONCLUSION: Kinematic MR imaging adds additional information when compared to conventional imaging methods in patients with advanced stages of degenerative disease of the cervical spine.

Cervical Vertebrae↗

PubMed1998

Biomechanical aspects of the subarachnoid space and cervical cord in healthy individuals examined with kinematic magnetic resonance imaging.

STUDY DESIGN: In vivo flexion-extension magnetic resonance imaging studies of the cervical spine were performed inside a positioning device. OBJECTIVE: To determine the functional changes of the cervical cord and the subarachnoid space that occur during flexion and extension of the cervical spine in healthy individuals. SUMMARY OF BACKGROUND DATA: As an addition to static magnetic resonance imaging examinations, kinematic magnetic resonance imaging studies of the cervical spine were performed to obtain detailed information about functional aspects of the cervical cord and the subarachnoid space. The results were compared with published data of functional flexion-extension myelograms of the cervical spine. METHODS: The cervical spines of 40 healthy individuals were examined in a whole-body magnetic resonance scanner from 50 degrees of flexion to 30 degrees of extension, using a positioning device. At nine different angle positions, sagittal T1-weighted spin-echo sequences were obtained. The images were analyzed with respect to the segmental motion, the diameter of the subarachnoid space, and the diameter of the cervical cord. RESULTS: The segmental motion between flexion and extension was 11 degrees at C2-C3, 12 degrees at C3-C4, 15 degrees at C4-C5, 19 degrees at C5-C6, and 20 degrees at C6-C7. At flexion, a narrowing of the ventral subarachnoid space of up to 43% and a widening of the dorsal subarachnoid space of up to 89% (compared with the neutral position, 0 degrees) were observed. At extension, an increase in the diameter of the ventral subarachnoid space of up to 9% was observed, whereas the dorsal subarachnoid space was reduced to 17%. At flexion, there was a reduction in the sagittal diameter of the cervical cord of up to 14%, and, at extension, there was an increase of up to 15%, compared with the neutral position (0 degrees; these values varied depending on the cervical segment. Statistically significant differences (P < 0.05) were found between flexion and extension in the diameter of the ventral and dorsal subarachnoid space and in the diameter of the cervical cord. CONCLUSIONS: Compared with the results of previous studies using functional cervical myelograms, kinematic magnetic resonance imaging provides additional noninvasive data concerning the physiologic changes of the cervical subarachnoid space and the cervical cord during flexion and extension in healthy individuals.

Adult↗

PubMed1998

Evaluation of articular cartilage thickness of the humeral head and the glenoid fossa by MR arthrography: anatomic correlation in cadavers.

OBJECTIVE: To evaluate the accuracy of MR arthrography in determining the thickness of articular cartilage of the humeral head and glenoid fossa. DESIGN AND PATIENTS: MR arthrography of the glenohumeral joint was performed in 17 cadaveric shoulders. Articular cartilage thickness was measured on the MR arthrographic images and corresponding anatomic sections. RESULTS: The correlation coefficients for MR arthrographic measurement versus anatomic measurement of the cartilage thickness were 0.7324 and 0.8757 for humeral head and glenoid fossa, respectively. With regard to the humeral head, there was a tendency to overestimate regions of thin cartilage and underestimate regions of thick cartilage. This tendency was not found in the assessment of glenoid cartilage. The mean of the absolute value of MR-anatomic differences was similar on the glenoid side (0.27 mm) and the humeral side (0.29 mm). The accuracy of measurement was significantly better on the glenoid side (Fisher's r-to-Z transformation: Z=5.21, P=0.000001). CONCLUSION: MR arthrography causes a moderate degree of error in the naked-eye measurement of the cartilage of the glenohumeral joint. The accuracy is higher on the glenoid side than on the humeral side.

Aged↗

PubMed1998

Critical evaluation of the specificity of MRI and TVUS for differentiation of malignant from benign adnexal lesions.

The aim of our work was to study the specificity of MRI in comparison with transvaginal US for differentiation of malignant from benign adnexal lesions. A total of 67 patients with clinically suspicious adnexal lesions were evaluated by MRI. Transaxial and coronal images were acquired using T1-weighted sequences before and following IV contrast and T2-weighted sequences. In all patients transvaginal ultrasound examinations (TVUS) were performed. For both imaging modalities each lesion was classified separately as either benign or malignant according to previously published criteria. Pathologic findings were available in 65 cases. Both MRI and TVUS correctly classified the 12 malignant lesions (sensitivity 100 %). Specificity (MRI: 78.2 %, TVUS: 65.5 %) and accuracy (MRI: 82 %, TVUS: 71.6 %) were higher with MRI than with TVUS, but differences were statistically not significant (p = 0.18 and p = 0.20, chi-square test). There was agreement/disagreement between findings of MRI and US in 52/15 lesions. The macroscopic criteria for malignancy are unspecific and result in a limitation of the specificity of both MRI and TVUS. The MRI technique is a valuable adjunct to TVUS by enabling further clarification of adnexal tumors with equivocal complex or solid vaginal sonographic findings.

Adnexal Diseases↗

PubMed1998

Skeletal involvement and follow-up in linear nevus sebaceous syndrome.

Linear nevus sebaceous syndrome is a rare neurocutaneous syndrome in which associated radiographic findings of the peripheral skeletal system are uncommon. We report a follow-up study of a patient with mainly unilateral changes of the skeletal system involving the thorax and the right arm and leg.

Abnormalities, Multiple↗

PubMed1998

[Ultra-rapid T2-weighted MR imaging during suspended respiration for the examination of focal lesions of the liver: a comparison of TSE, HASTE and HASTE-STIR sequences using a CP body array coil].

PURPOSE: A comparison of ultra rapid T2-weighted HASTE and HASTE-STIR sequences during suspended respiration for the detection of focal lesions of the liver. MATERIAL AND METHODS: Twenty-one patients (59 +/- 12 years) with a total of 33 focal lesions (7 < or = 1 cm, 19 < or = 3 cm; 17 cystic liquid and 16 solid lesions) were examined with a 1.5 T MR apparatus. Sequences: T2 weighted HASTE (TEeff = 64 ms, 90 ms), HASTE-STIR (TEeff = 64 ms, 81 ms) TSE (TE = 132 ms) and T1-weighted FLASH 2D. RESULTS: The T2-weighted TSE and both HASTE sequences showed all the lesions. Two out of the 33 lesions were not demonstrated by the other sequences. Best image quality without movement artefacts and the best resolution of the lesions in the T2-weighted sequences, with the most favourable contrast/noise ratio (36.6 +/- 33.1) and signal/noise ratio (20.8 +/- 10.5) resulted from the HASTE 90, followed by the HASTE 64 sequence (27.5 +/- 24.2; 24.6 +/- 9.1). Both these techniques were superior to the TSE sequence (23.9 +/- 29.4; 13.9 +/- 7.4), which resulted in movement artifacts. With the HASTE-STIR sequences it was possible to show 31 and 32 of the 33 lesions respectively, with very good resolution but poor signal/noise ratio. CONCLUSION: HASTE sequences have the potential of improving the diagnosis of focal liver lesions.

Adenoma↗

PubMed1998

Exacerbated pain in cervical radiculopathy at axial rotation, flexion, extension, and coupled motions of the cervical spine: evaluation by kinematic magnetic resonance imaging.

RATIONALE AND OBJECTIVES: The authors evaluate the functional changes in patients with cervical radiculopathy and increasing symptoms after provocative maneuvers at flexion, extension, axial rotation, and coupled motions of the cervical spine. METHODS: Twenty-one patients with cervical disc herniation (n = 17) or cervical spondylosis (n = 4) in whom symptoms were elicited at flexion, extension, axial rotation, and coupled motions of the cervical spine were studied. The patients were examined inside a positioning device by using a circular surface coil for signal reception. At neutral position (0 degrees) and at provocative positions sagittal T2-weighted turbo spin-echo, axial T2-weighted two-dimensional flash sequence, sagittal three-dimensional (3D) fast imaging with steady state precision sequence and coronal 3D double-echo-in-the-steady-state sequences were obtained. The 3D sequences were reformatted in the axial and oblique coronal planes perpendicular to the exiting nerve roots. The images were evaluated for the size of disc herniations, the foraminal size and cervical cord rotation or displacement at provocative position compared with neutral position (0 degrees). RESULTS: Compared with neutral position (0 degrees), change in size of disc herniation was not found in any (0%) of the provocative positions. In five (24%) patients cervical cord rotation or displacement was noted at axial rotation. The foraminal size increased at flexion, axial rotation to the opposite side of pain and flexion combined with axial rotation to the opposite side of the pain. The foraminal size decreased at extension combined with axial rotation to the side of the pain. A decrease or no change in foraminal size was observed at either extension or axial rotation to the side of the pain. CONCLUSIONS: In patients with cervical disc herniation or cervical spondylosis, exacerbated pain at defined provocative maneuvers is related more to changes in the foraminal size and to nerve root motion with, in some cases, cervical cord rotation or displacement than to changes in the size of herniated discs.

Adult↗

PubMed1998

Evaluation of the triangular fibrocartilage and the scapholunate and lunotriquetral ligaments in cadavers with low-field-strength extremity-only magnet. Comparison of available imaging sequences and macroscopic findings.

RATIONALE AND OBJECTIVES: The authors assessed the ability of a low-field-strength extremity-only magnet to provide visualization of the triangular fibrocartilage and the scapholunate and lunotriquetral ligaments. METHODS: Twelve human wrists were examined with a 0.2 T extremity-only magnet. T1-weighted spin echo, proton density-weighted, and T2-weighted turbo spin echo, short-tau inversion recovery, and three-dimensional gradient recalled echo images were acquired, and sections of the specimens were then made that corresponded to the magnetic resonance images. Masked imaging analyses were correlated with macroscopic and limited histopathologic findings. RESULTS: Low-field-strength extremity-only magnet allowed consistent visualization of the triangular fibrocartilage and accurate assessment of a small number of complete tears of the triangular fibrocartilage. The scapholunate ligaments in all cases were identified using a combination of imaging sequences. Consistent visualization of the lunotriquetral ligament with a low-field-strength extremity magnet was difficult. CONCLUSIONS: Magnetic resonance imaging with a low-field-strength extremity-only magnet can be used to visualize the triangular fibrocartilage and the scapholunate ligament, but not the lunotriquetral ligament.

Aged↗

PubMed1998

Dynamic changes of the spinal canal in patients with cervical spondylosis at flexion and extension using magnetic resonance imaging.

RATIONALE AND OBJECTIVES: The authors determine the dynamic changes of the spinal canal during flexion and extension in patients with cervical spondylosis. METHODS: Forty-six patients were studied inside a whole-body magnetic resonance (MR) scanner with between 50 degrees of flexion and 30 degrees of extension, using a positioning device. At neutral position (0 degree) and maximum flexion and extension sagittal T2-weighted turbo spin echo sequences were acquired. RESULTS: A significant (P < or = 0.05) increase of spinal stenosis was found at extension (48%, 22 of 46 patients) when compared with flexion (24%, 11 of 46). Cervical cord compression was diagnosed at flexion in 5 patients (11%) and at extension in 9 patients (20%). Concerning the number of patients with cervical cord compression at flexion and extension, significant differences (P < or = 0.05) were found in patients with degenerative changes at four segments compared with patients with one segment involvement. CONCLUSIONS: Magnetic resonance imaging identified a significant percentage of increased spinal stenosis at flexion and, especially, at extension, which was not observed at neutral position (0 degree). Flexion and extension MR imaging demonstrates additional information using a noninvasive technique concerning the dynamic factors in the pathogenesis of cervical spondylotic myelopathy.

Adult↗

PubMed1998

Evaluation of patellar cartilage in cadavers with a low-field-strength extremity-only magnet: comparison of MR imaging sequences, with macroscopic findings as the standard.

PURPOSE: To assess a low-field-strength extremity-only magnet in the evaluation of patellar cartilage abnormalities. MATERIALS AND METHODS: Four regions in each of 10 patellae from cadavers were examined in the transaxial plane with a 0.2-T extremity-only magnet and the following sequences: T1-weighted spin echo, proton density- and T2-weighted turbo spin echo, short inversion time inversion recovery, and two- and three-dimensional gradient echo with and without magnetization transfer contrast subtraction. Lesions depicted with MR imaging and seen in anatomic sections of the patellae were classified according to a modified standardized arthroscopic grading system. MR imaging and pathologic correlation was then analyzed. RESULTS: On the basis of macroscopic findings, 14 of 40 cartilage regions were found to be intact, grade 2A lesions were present in eight regions, grade 2B lesions in eight, and grade 3 lesions in 10. For the various MR imaging techniques, sensitivity was 25%-62% for grade 2A lesions, 50%-75% for grade 2B lesions, and 60%-90% for grade 3 lesions. Specificity was 81%-97% for grades 2A and 2B lesions, and 80%-97% for grade 3 lesions. Accuracy was 75%-82% for grade 2A lesions, 75%-92% for grade 2B lesions, and 80%-92% for grade 3 lesions. CONCLUSION: High-grade cartilaginous lesions can be evaluated reliably with low-field-strength MR imaging by using a combination of imaging sequences.

Aged↗

PubMed1998

Anterior labroligamentous structures of the glenohumeral joint: correlation of MR arthrography and anatomic dissection in cadavers.

OBJECTIVE: The purpose of this study was to establish the accuracy of MR arthrography in depicting the morphology of the glenohumeral ligaments and the superior portion of the glenoid labrum. MATERIALS AND METHODS: Findings on MR arthrography and those derived from careful dissection of gross specimens were compared in 15 cadaver shoulders, focusing on the morphology and size of the superior and middle glenohumeral ligaments and the morphology of the inferior glenohumeral ligament. The frequencies of sublabral recess and sublabral foramen seen on MR arthrography and at anatomic dissection were also compared. RESULTS: For the superior and middle glenohumeral ligaments, moderate correlation of size was found between measurements made on MR arthrograms and at anatomic dissection, with the Spearman's rank correlation coefficient calculated as .69990 and .71133, respectively. Morphologic descriptions of the inferior glenohumeral ligament based on MR arthrography and on anatomic dissection also showed good association (Cohen's kappa = .8936). Dissection revealed that the sublabral recess was present in 11 specimens. Of these, 10 recesses were identified on MR arthrograms. MR arthrography also revealed a sublabral recess that was not found at dissection. Four sublabral foramina were identified by both MR arthrography and dissection, and two were revealed only by MR arthrography. CONCLUSION: MR arthrography is useful in the evaluation of the glenohumeral ligaments and the superior portion of the labrum. Anatomic variations of these anterior intraarticular structures can be accurately shown by MR arthrography. In addition, estimation of the size of glenohumeral ligaments can be achieved with acceptable accuracy on MR arthrograms.

Aged↗

PubMed1998

Classification system based on kinematic MR imaging in cervical spondylitic myelopathy.

BACKGROUND AND PURPOSE: Functional myelographic studies are often used to evaluate the dynamic changes of the cervical spinal canal during flexion and extension. The purposes of this study were to use kinematic MR imaging to assess the dynamic changes of the cervical spine in patients at different stages of degenerative disease and to describe a classification system based on static and dynamic factors in the pathogenesis of cervical spondylitic myelopathy. METHODS: Eighty-one patients with different stages (I-IV) of degenerative disease of the cervical spine were examined with MR imaging. In the neutral position (0 degrees) and at maximum flexion and extension, spinal stenosis was classified for each segment according to the following grading system: 0 = normal, 1 = partial obliteration of the anterior or posterior subarachnoid space, 2 = complete obliteration of the anterior or posterior subarachnoid space, and 3 = cervical cord compression or displacement. RESULTS: At flexion and extension, the prevalence of spinal stenosis and cervical cord impingement increased as the stage of degenerative disease progressed. With regard to a pincer effect (anterior and posterior cord impingement) and cord encroachment at multiple segments, statistically significant differences were observed at stages III and IV as compared with stages I and II. Significant increase in cord impingement was seen in 22 (27%) of 81 patients at extension, as compared with four (5%) of 81 patients at flexion. CONCLUSION: Regardless of the stage of degenerative disease and grade of spinal stenosis at the neutral position (0 degrees), cervical spinal motion may contribute to the development of cervical spondylitic myelopathy.

Adult↗

PubMed1997

MRI of the nasal cavity, the paranasal sinuses and orbits in Wegener's granulomatosis.

The purpose of this study was to evaluate diagnostic MRI criteria in Wegener's granulomatosis of the nasal cavity, the paranasal sinuses and orbits. Between March 1991 and January 1996, 62 patients with biopsy-proven Wegener's granulomatosis were studied with T1- and T2-weighted spin-echo (SE) sequences. In 32 patients coronal postcontrast T1-weighted images were obtained. Mucosal thickening of the nasal cavity and paranasal sinuses was demonstrated as high-intensity lesions on T2-weighted SE sequences in 57 patients (92%). Of this group, inflammatory granulomatous tissue was found on biopsy in 30 patients (48%) in the nasal cavity and in 4 patients (6%) in the paranasal sinuses. In 23 patients (37%) biopsy revealed unspecific inflammatory changes without evidence of granulomatous tissue. In 14 patients (23%) granulomas were depicted as low-signal intensity lesions on T1- and T2-weighted SE sequences in the paranasal sinuses and orbits. In 5 patients (8%) osseous destruction was found. After gadolinium injection, 12 of 14 granulomas showed inhomogeneous signal enhancement. In two granulomas no enhancement was found. The MRI technique is helpful in the diagnosis of patients with Wegener's granulomatosis. In the initial inflammatory process of Wegener's granulomatosis, it is not possible to differentiate between mucosal inflammation and granulomatous tissue in MRI. In the later stage of granulomatous transformation, granulomas can be depicted as low-signal-intensity lesions. Therefore, Wegener's granulomatosis should be included in the differential diagnosis of patients with low-signal-intensity lesions on T1- and T2-weighted SE sequences of the nasal cavity, paranasal sinuses and orbits.

Adult↗