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Biomedical subjects

C Muhle

Publications and source records attributed to C Muhle.

At least 19 recordsLinked to original sources

Sentinel lymph-node biopsy in head and neck cancer.

The aim of the study was to assess the diagnostic value of the sentinel node method in patients suffering from squamous cell carcinoma of the upper aerodigestive tract. In 50 patients with oral, pharyngeal or laryngeal carcinomas staged N0 up to 50 MBq technetium-99m colloid were injected peritumorally. Sentinel nodes were localised using a gamma-probe in the setting of an elective neck dissection. Pathological findings of sentinel nodes and corresponding neck specimens were compared. In 46 patients sentinel nodes were detected. Of these 34 patients were free of metastatic disease in the sentinel nodes and in the neck specimens. In 12 patients clinically occult metastases were found in the sentinel nodes. Three metastases were detected only after additional sectioning of the sentinel nodes. In four patients, a sentinel lymph node could not be localised. Our results support the sentinel node concept in head and neck cancer and a definition of the sentinel nodes as the three nodes with the highest activity. Careful clinical staging of the neck and thorough pathological evaluation of the sentinel nodes are necessary to avoid false-negative results.

Carcinoma, Squamous Cell↗

Correlation between HRCT findings, pulmonary function tests and bronchoalveolar lavage cytology in interstitial lung disease associated with rheumatoid arthritis.

A prospective study correlating high-resolution computed tomography (HRCT), lung function tests (PFT) and bronchoalveolar lavage (BAL) cytology in patients with interstitial lung disease (ILD) associated with rheumatoid arthritis (RA). Fifty-three RA patients with suspected ILD (19 men, 34 women) underwent 71 HRCT (14 of 53 with sequential HRCT, mean follow-up 24.3 months). The HRCT evaluation by two observers on consensus included a semi-quantitative characterisation of lesion pattern and profusion on representative anatomical levels. Fifty-two HRCT were followed by PFT and BAL. Agreement or discordance of HRCT-, PFT- and BAL findings were analysed with Pearson's correlation, kappa score and McNemar's test. Tobacco-fume exposure was estimated in pack years. Smoking/non-smoking groups were compared with Student's t test. In 49 of 53 patients, HRCT was suggestive of ILD associated with RA (66 of 71 HRCT). Reticular lesions were found in 40 of 53 patients, in 15 of 40 presenting as mixed pattern with ground-glass opacities (GGO). Pure reticular patterns predominated in patients with long duration of ILD (p>0.01). Pure GGO were not observed. Lesion profusion was highly variable and correlated moderately negative with diffusion capacity (mean 88.2% (SD +/- 20.9%); r=-0.54; p<0.001) and very weak with vital capacity and FEV1 (mean values 92.2% (SD +/- 18.3%); r=-0.27; p<0.05 and 89.8% (SD +/- 17.5%); r=-0.31; p<0.01). In patients with GGO, BAL differentials tended towards neutrophilia (kappa=0.39; p=0.04; McNemar test p>0.2), but not towards lymphocytosis (kappa=0.10; p=0.23; McNemar test p>0.2). Differences in smoking history were not significant (p>0.1). The HRCT appears most appropriate for the detection and follow-up of ILD associated with RA. The PFT and BAL correlate only partially with lesion profusion or grading on HRCT, but they contribute valuable information about dynamic lung function and differential diagnoses (pneumonia, medication side effects).

Aged↗

Value of micro-CT as an investigative tool for osteochondritis dissecans.

PURPOSE: To evaluate micro computed tomography (micro-CT) for the assessment of osteochondritis dissecans in comparison with histology. MATERIAL AND METHODS: Osteochondritis dissecans lesions of 3 patients were evaluated using micro-CT (0.125 mA, 40 keV, 60 microm slice thickness, 60 microm isotropic resolution, entire sample) and light microscopy (toluidine blue, 3-5 microm slice thickness). The methods were compared regarding preparation time, detectability of tissue types and morphologic features of bone and cartilage. RESULTS: Non-destructive micro-CT imaging of the entire sample was faster than histologic preparation of a single slice for light microscopy. Morphologic features of bone and cartilage could be imaged in a comparable way to histology. It was not possible to image cells or different tissue types of bone and cartilage with micro-CT. CONCLUSION: Micro-CT is a fast, non-destructive tool that may be a supplement or, if detailed histologic information is not necessary, an alternative to light microscopy for the investigation of osteochondritis dissecans.

Adult↗

[Alar ligaments: radiological aspects in the diagnosis of patients with whiplash injuries].

Post-traumatic changes of the alar ligaments have been proposed to be the cause of chronic pain in patients after whiplash injury of the cervical spine. In addition to an asymmetric dens position, widening of the atlantodental distance to more than 12 mm can be an indirect sign of an alar ligament rupture. CT is recommended for detection of a avulsion fracture of the occipital condyle. Isolated ruptures of the alar ligaments are best visualized on MRI. In patients with chronic impairments after whiplash injuries changes of the alar ligaments on MRI must be differentiated from normal variants in healthy individuals.

Adult↗

[Sensitivity of MRI in detecting alveolar Infiltrates: Experimental studies].

PURPOSE: An experimental study using porcine lung explants and a dedicated chest phantom to evaluate the signal intensity of artificial alveolar infiltrates with T 1 - and T 2 -weighted MRI sequences. MATERIAL AND METHODS: 10 porcine lung explants were intubated, transferred into the cavity of a MRI-compatible chest phantom and inflated by continuous evacuation of the artificial pleural space. All lungs were examined with MRI at 1.5 T before and after intra-tracheal instillation of either 100 or 200 ml gelatine-stabilised liquid to simulate alveolar infiltrates. MR-examination comprised gradient echo (2D- and 3D-GRE) and fast spin echo sequences (T 2 -TSE and T 2 -HASTE). The signal intensity of lung parenchyma was evaluated at representative cross sections using a standardised scheme. Control studies were acquired with helical CT. RESULTS: The instilled liquid caused patchy confluent alveolar infiltrates resembling the findings in patients with pneumonia or ARDS. CT revealed typical ground-glass opacities. Before the application of the liquid, only T 2 -HASTE and T 2 -TSE displayed lung parenchyma signals with a signal/noise ratio of 3.62 and 1.39, respectively. After application of the liquid, both T 2 -weighted sequences showed clearly visible infiltrates with an increase in signal intensity of approx. 30 % at 100 ml (p < 0.01) and 60 % at 200 ml (p < 0.01). With 2D- and 3D-GRE the infiltrates were not visible, although the lung parenchyma signal increase was statistically significant. On 2D-GRE the increase in signal intensity reached 0.74 % (p = 0.32) after 100 ml and 5.6 % (p < 0.01) after 200 ml (for 3D-GRE: 2.2 % [p = 0.02] at 100 ml and 4.4 % at 200 ml [p < 0.01]). The CT controls revealed a significant increase of lung density of 17 H.E. at 100 ml (p = 0.02) and 75 H.E. at 200 ml (p < 0.01). CONCLUSIONS: MRI with T 2 -weighted sequences detects artificial alveolar infiltrates with high signal intensity and may be a highly sensitive tool to detect pneumonia in patients.

Animals↗

Acetabular inclination and anteversion in infants using 3D MR imaging.

PURPOSE: To establish if 3D MR imaging could be used for measurements of acetabular inclination and anteversion in infants specimens. MATERIAL AND METHODS: 3D MR data of 3 pelvic preparations of 6-week- to 10-month-old infant specimens was gathered. MR imaging in transaxial and frontal planes was carried out to measure the acetabular inclination and anteversion: a method to determine the MR planes for measurements is described. It was oriented on anatomical landmarks of the pelvis and therefore allowed adjustment of the frontal and transaxial planes, independent of the pelvis position. RESULTS: The mean acetabular inclination angle was 48 degrees, and the mean acetabular anteversion was 23 degrees. Because of the low number of cases the results can only be assessed as a tendency, but MR imaging seems to be suitable for measurements of acetabular inclination and anteversion.

Acetabulum↗

Analysis of artefacts and detail resolution of lung MRI with breath-hold T1-weighted gradient-echo and T2-weighted fast spin-echo sequences with respiratory triggering.

The aim of this study was to evaluate feasibility and limitations of two MR sequences for imaging of the lung using a semi-quantitative rating scale. Ten healthy volunteers were assessed with a breath-hold T1-weighted gradient-recalled-echo (TR/TE=129/2.2 ms, matrix 173 x 256) and a T2-weighted turbo spin-echo (TSE) sequence with respiratory triggering (TR/TE=3000-5000/120 ms, matrix 270 x 512) in axial 6-mm slices. The T1-weighted GRE protocol included a pre-saturation pulse over the mediastinal structures. Artefacts and resolution of vessel/airway structures in each lung segment were evaluated by two observers (10 volunteers, 180 segments). Cardiac and vessel pulsation artefacts predominated on T1-weighted GRE, respiration artefacts on T2-weighted TSE (lingula and middle lobe). Pre-saturation of the mediastinum reduced pulsation artefacts on T1-weighted GRE. T1-weighted GRE images were improved by bright flow signal of vessels, whereas image quality of T2-weighted TSE was reduced by black-blood effects in central parts of the lung. Delineation of lung periphery and the mediastinum was superior with T2-weighted TSE. Segmental/sub-segmental vessels (up to fourth/fifth order) and bronchi (up to third order) were identified. All 180 lung segments were imaged in diagnostic quality with at least one of the two sequences (T1-weighted GRE not diagnostic in 9 of 180, T2-weighted TSE in 4 of 180). Both sequences were found to be complementary: superior identification of gross lung anatomy with T1-weighted GRE and higher detail resolution in the periphery and the mediastinum with T2--weighted TSE.

Adult↗

In vivo changes in the neuroforaminal size at flexion-extension and axial rotation of the cervical spine in healthy persons examined using kinematic magnetic resonance imaging.

STUDY DESIGN: In vivo flexion-extension and axial rotation magnetic resonance imaging (MRI) studies of the cervical spine were performed inside a positioning device. OBJECTIVE: To determine the functional changes of neuroforaminal size that occur during flexion-extension and axial rotation of the cervical spine in healthy persons. SUMMARY OF BACKGROUND DATA: Kinematic MRI studies of the cervical spine were performed to obtain detailed information about the functional changes that occur in neuroforaminal size during flexion-extention and axial rotation. The results were compared with published data of in vitro functional flexion-extension and axial rotation studies of the cervical spine. METHODS: Inside a positioning device, the cervical spines of 30 healthy persons were examined in a whole-body magnetic resonance scanner from 40 degrees of flexion to 30 degrees of extension at nine different angle positions. In addition, axial rotation was performed at neutral position (0 degrees ) and at 20 degrees and 40 degrees of axial rotation to both sides. The images were analyzed with respect to the neuroforaminal size at each position using a reformatted 3D-FISP sequence. RESULTS: At flexion, widening of the neuroforaminal size of up to 31% (compared with neutral position, 0 degrees ) was observed. Conversely, at extension a decrease in the size of the neuroforamen of up to 20% was recognized. At 20 degrees and 40 degrees of ipsilateral rotation of the head, a reduction in the neuroforaminal size of up to 15% and 23%, respectively, compared with the neutral position was noted. In contrast, a widening of the foraminal size was recognized on the contralateral side of 9% and 20% at 20 degrees and 40 degrees rotation. Statistically significant differences (p <== 0.05) were found in the neuroforaminal size between different degrees of flexion and extension and in addition for axial rotation compared to neutral position (0 degrees ). CONCLUSION: Compared with the results of previous biomechanical studies of human cadaver cervical spines, kinematic MRI provides additional noninvasive data concerning the physiological changes of the neuroforaminal size during flexion-extension and axial rotation in healthy individuals.

Adult↗

Magnetic resonance arthrography of the acetabular labrum: value of radial reconstructions.

The intention was to compare the sensitivity and specificity of radial planes with oblique coronal and oblique axial planes for the detection of labral abnormalities of the acetabulum on magnetic resonance arthrography (MRa). Twenty cadaveric hip joints were examined by radiography and MRa. For MRa, 15 ml of a solution of iodinated contrast material and gadolinium diethylene triamine tetra-acetic acid (Gd-DTPA; 100:1) were injected under fluoroscopic guidance. MRI was performed on a 1.5-T MR scanner with a fat-suppressed 3D-FLASH sequence (TR/TE/flip-angle 42 ms/10 ms/40 degrees; field of view 16 cm, matrix 256 x 256, section thickness 1.5 mm, pixel size 0.7 x 0.7 mm). Multiplanar image reconstructions were done perpendicular to the acetabulum in oblique coronal and oblique axial planes and in radial planes. Macroscopic and histopathologic examination of the labral specimens was performed. Labral lesions were found in 15/20 hips (75%) on pathologic examination. Six hips demonstrated labral degeneration. The labrum was partially detached in 7 hips and completely detached in 2 hips. A flap-like labrum was found in 2 cases, 1 with partial detachment of the labrum and 1 with a degenerated labrum. Using oblique coronal and oblique axial reconstructions, pathologic findings were confirmed by MRa in 9/15 specimens (sensitivity 60%). There were no false-positive findings (specificity 100%, accuracy 70%). Also, 3/6 labral degenerations without detachment, 4/7 partial detachments, and 2/2 complete detachments were correctly diagnosed. Two flap-like labra were not recognized. With radial reconstructions, pathologic findings were correctly confirmed in 12/15 specimens (sensitivity 80%) without false-positive findings (specificity 100%, accuracy 85%). Also, 3/6 labral degenerations without detachment, 6/7 partial detachments, 2/2 complete detachments, and 1/2 flap-like labra were correctly diagnosed. MRa of the acetabular labrum using radial reconstructions is well suited to delineate the acetabular labrum and to diagnose labral detachments. Radial reconstructions allow for perpendicular display of the whole acetabular circumference and are more accurate for the diagnosis of acetabular labral lesions, when compared with oblique coronal and oblique axial reconstructions.

Acetabulum↗

[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↗

[MR imaging of the articular cartilage].

MR imaging has evolved to the best non-invasive method for the evaluation of articular cartilage. MR imaging helps to understand the structure and physiology of cartilage, and to diagnose cartilage lesions. Numerous studies have shown high accuracy and reliability concerning detection of cartilage lesions and early changes in both structure and biochemistry. High contrast-to-noise ratio and high spatial resolution are essential for analysis of articular cartilage. Fat-suppressed 3D-T1 weighted gradient echo and T2-weighted fast spin echo sequences with or without fat suppression are recommended for clinical routine. In this article the anatomy and pathology of hyaline articular cartilage and the complex imaging characteristics of hyaline cartilage will be discussed.

Arthrography↗

High-dose treatment with (186)Re-HEDP or (153)Sm-EDTMP combined with amifostine in a rabbit model.

UNLABELLED: The aim of this experimental study was to investigate the myeloprotective potential of amifostine in rabbits receiving high-dose treatment with either (153)Sm-ethylenediaminetetramethylene phosphonate (EDTMP) or (186)Re-hydroxyethylidene diphosphonate (HEDP) and to check for drug interactions impairing the skeletal uptake of these radiopharmaceuticals by amifostine. METHODS: To a total of 24 rabbits, we administered 1,000 MBq of either (153)Sm-EDTMP (n = 12) or (186)Re-HEDP (n = 12). Six animals of each group received 500 mg amifostine intravenously 10-15 min before injection of the radiopharmaceutical, whereas the other 6 animals served as controls. Up to 8 wk after treatment, blood samples were collected every 3-5 d to measure platelet and leukocyte counts. Furthermore, whole-body images were acquired at 3 min, 3 h, and 24 h after injection of the radiopharmaceutical to quantify the skeletal uptake. RESULTS: For (186)Re-HEDP, the mean decrease in platelets was significantly less in the amifostine group (35.5% +/- 2.4%) than in the control group (61.3% +/- 5.4%, P < 0.001). Similar results were found for (153)Sm-EDTMP (36.5% +/- 8.3% vs. 52.3% +/- 14.0%, P < 0.05). No significant differences in leukocyte counts were found for (186)Re-HEDP (75.3% +/- 12.3% in the amifostine group and 72.5% +/- 4.1% in the control group, P > 0.05), whereas rabbits treated with (153)Sm-EDTMP plus amifostine showed a significantly greater decrease in leukocytes (69.2% +/- 10.8%) than did the control group (56.6% +/- 4.0%, P < 0.05). Bone uptake in percentage of initial total whole-body activity was significantly decreased in animals treated with amifostine compared with the control groups for both (186)Re-HEDP (15.8% +/- 3.1% vs. 30.9% +/- 1.9%, P < 0.001) and (153)Sm-EDTMP (31.7% +/- 8.9% vs. 44.0% +/- 6.5%, P < 0.05). CONCLUSION: For amifostine, we found a highly significant cytoprotective effect on platelets but no leukoprotective effect. The latter probably relies on the intrinsic myelotoxicity of high-dose amifostine, which seemed to potentiate the leukodepression of the radiopharmaceuticals. The lower bone uptake in amifostine-treated animals may be caused by the chemical structure of amifostine, which is a potentially complex-forming compound that may be able to displace bisphosphonates from the rhenium- and samarium-bisphosphonate complexes, resulting in altered biodistribution patterns.

Amifostine↗

[Quantification of fluid flow in magnetic resonance tomography: an experimental study of a flow model and liquid flow measurements in the cerebral aqueduct in volunteers].

PURPOSE: To study the feasibility o MRI for quantification of fluid flow in a tube model and the cerebral aqueduct (CA) in volunteers. VOLUNTEERS AND METHODS: All studies were performed on a 1.5 T MR scanner using a head coil and a FLASH 2D phase contrast sequence with a velocity encoding at 20 cm/s. Flow (real value, ml/sec) of a saline fluid was measured in a flexible tube model with different inside diameters: 0.75-3 mm. Three flow velocities were given (normal value). To test the reproducibility, three studies were done using a flow of 0.12 or 0.14 ml/sec and a tube diameter of 0.75 and 2.0 mm. The ratio of normal to real flow value was calculated (ideal ratio = 1). MRI of CA and flow quantification was done in 24 volunteers (28 +/- 4 years). RESULTS: Using tubes with a diameter of 0.75 and 1.5 mm the real flow was sometimes higher than the velocity encoding of the phase contrast sequences. Because of this measurements of the fluid flow and the flow velocities were impossible. There was agreement for fluid flow quantification in the tube of 3.0 mm and high agreement in the tube of 2.0 mm in diameter with reproducible results. The mean diameter of the CA in normal subjects was 2.0 +/- 0.3 mm, the mean cerebral flow was 0.04 +/- 0.02 ml/sec and the peak velocity 3.06 +/- 1.59 cm/sec. CONCLUSIONS: Reliable flow quantification with MRI is feasible if the diameter of the lumen is greater than 1.5 mm, and if the flow velocity is lower than the velocity encoding. In cases of smaller diameters and higher flow velocities the velocity encoding has to be changed. Because of this the quantification seems to be inaccurate in cases of aqueductal stenosis with the method we used.

Adult↗

Radiation exposure to the personnel in the operating room and in the pathology due to SLN detection with Tc-99m-nanocolloid in breast cancer patients.

UNLABELLED: AIM of this study was to assess the radiation exposure for the personnel in the operating room and in the pathology laboratories caused by radioguided SLN localization in breast cancer. METHODS: In 15 patients dose rates were measured at various distances from the breast and tumor specimens during operation and pathological work-up at 3-5 h after peritumoral injection of 30 MBq Tc-99m-nanocolloid. RESULTS: The dose rates were 84.1 +/- 46.4 microGy/h at 2.5 cm, 3.57 +/- 2.14 microGy/h at 30 cm, 0.87 +/- 0.51 microGy/h at 100 cm, and 0.40 +/- 0.20 microGy/h at 150 cm in the operating room and 44.4 +/- 27.8 microGy/h at 2.5 cm, and 1.66 +/- 1.34 microGy/h at 30 cm in the pathology laboratories. From these data the radiation exposure was calculated for 250 operations per year assuming a mean exposure time of 30 min for the surgical team members and of 10 min for the pathology staff. Under these conditions the finger dose is 10.5 mGy for the surgeon, and 5.55 mGy for the pathologist. The whole-body doses are 0.45 mSv, 0.11 mSv, 0.05 mSv, and 0.21 mSv for the surgeon, the operating room nurse, the anesthetist, and the pathologist, respectively. CONCLUSION: Since the radiation risk to staff members is low, a classification of the personnel in the operating room and in the pathology laboratories as occupational radiation exposed workers is not necessary.

Breast Neoplasms↗

Intracapsular origin of the long head of the biceps tendon.

A developmental anomaly of the long head of the biceps tendon was found in a cadaveric shoulder. Findings on arthroscopy, routine MR imaging, and MR arthrography were compared and correlated with results of anatomic dissection. MR arthrography appears to be a very good diagnostic imaging method for depicting this anomaly prior to arthroscopy.

Aged↗

Peripheral focal low signal intensity areas in the degenerated annulus fibrosus on T2-weighted fast spin echo MR images: correlation with macroscopic and microscopic findings in elderly cadavers.

OBJECTIVE: To correlate the peripheral focal low signal intensity areas in the degenerated annulus fibrosus on T2-weighted fast spin echo MR images with the macroscopic and microscopic findings in cadavers derived from elderly subjects. DESIGN: Twenty-eight intervertebral disks (16 lumbar and 12 cervical) derived from four nonembalmed cadavers were examined with T1-weighted spin echo and proton density-weighted and T2-weighted fast spin echo MR imaging. The signal intensities of the annulus fibrosus were evaluated on sagittal MR images and correlated with the findings on corresponding sagittal anatomic sections. The MR imaging-histologic correlation was then studied. RESULTS: Peripheral focal low signal intensity areas and adjacent regions of high signal intensity were found in five lumbar intervertebral disks. Peripheral focal low signal intensity regions consisted of disorganized compact annular fibers, tiny fissures, and dense fibrosis. The high signal intensity regions, adjacent to the areas of low signal intensity, consisted of mucoid degeneration, tiny fissures, and chondroid metaplasia. CONCLUSIONS: Awareness of the histologic findings in regions that reveal peripheral focal low signal intensity with adjacent regions of high signal intensity in the degenerated annulus fibrosus on T2-weighted images may facilitate effective interpretation of clinical MR images of the spine.

Aged↗

Evaluation of the postoperative meniscus of the knee: a study comparing conventional arthrography, conventional MR imaging, MR arthrography with iodinated contrast material, and MR arthrography with gadolinium-based contrast material.

OBJECTIVE: To compare four imaging methods in the evaluation of the postoperative meniscus: conventional arthrography, conventional MR imaging, MR arthrography with iodinated contrast material, and MR arthrography with gadolinium-based contrast material. DESIGN AND PATIENTS: Thirty-three patients referred for knee MR examinations with a history of meniscal surgery were studied prospectively. At the first patient visit, conventional MR examination was followed by an MR arthrogram with gadolinium-based contrast material. At the second visit, a conventional arthrogram with iodinated contrast material was followed immediately by an MR examination. Imaging examinations were interpreted by a masked reader, and then compared with the results of repeat arthroscopic surgery in 12 patients. RESULTS: The correct evaluation of the status of postoperative menisci was allowed in 12 of 13 patients (92%) by MR arthrography using gadolinium-based contrast agent, 10 of 13 patients (77%) by conventional MR examination, 9 of 12 patients (75%) by MR arthrography, and 7 of 12 patients (58%) by conventional arthrography. CONCLUSION: Intra-articular fluid is advantageous in the evaluation of patients with a suspected meniscal retear. MR arthrography with gadolinium-based contrast material is the most accurate imaging method for the diagnosis of meniscal retears.

Adult↗