Head and neck MR imaging in the pediatric patient

Magnetic resonance (MR) imaging studies of the head and neck (excluding the brain) were obtained in 49 children believed to have lesions of the head and neck. Seven children had normal images; in the remaining 42, lesions were divided into four categories: midline lesions, lesions of symmetric paired structures, facial lesions, and nasopharyngeal and oropharyngeal lesions. All entities were well delineated by MR imaging. The imaging planes and sequences chosen depended on the suspected abnormality. Midline lesions were best imaged in the sagittal plane, lesions of paired structures and the face in the axial or coronal planes, and nasopharyngeal and oropharyngeal lesions in the axial or sagittal planes. Intracranial extension of head and neck neoplasms was best evaluated in the coronal plane. Surface coils provided better resolution and were thus more useful in evaluating small superficial lesions; head or body coils were more useful in defining the extent of large lesions. T2-weighted images provided better differentiation between normal and tumor tissue in patients with head and neck neoplasms.     

Magnetic resonance imaging of the brachial plexus. Anatomy

The brachial plexus is a difficult region to evaluate with radiological techniques. MR imaging has great potentials for the depiction of the various anatomical structures of the brachial plexus--i.e., spinal ganglion, ventral nerve rami root exit of the neural foramina, trunks and cords. Moreover, MR imaging, thanks to its direct multiplanarity, to its excellent soft-tissue contrast, and to its lack of motion artifacts, allows good evaluation of pathologic conditions in the brachial plexus, especially traumas and cancers. On the contrary CT, in spite of its high spatial resolution and good contrast, cannot demonstrate the anatomical structures of the brachial plexus. US detects superficial structures, and conventional radiographs depict only indirect changes in the adjacent lung apex and skeletal structures. From November 1989 to May 1990, 20 normal volunteers (15 males and 5 females; average age: 35 years) were studied with MR imaging. Multisection technique was employed with a dedicated coil and a primary coil. The anatomical structures of the brachial plexus were clearly demonstrated by T1-weighted sequences on the sagittal and the axial planes. T2-weighted pulse sequences on the coronal plane were useful for the anatomical definition of the brachial plexus and for eventual tissue characterization. The correct representation of the anatomical structures of the brachial plexus allowed by MR imaging with our standard technique makes MR imaging the most appropriate exam for the diagnosis of pathologic conditions in the brachial plexus, although its use must be suggested by specific clinical questions.     

Accuracy of T2-weighted fast spin-echo MR imaging with fat saturation in detecting cartilage defects in the knee: comparison with arthroscopy in 130 patients

OBJECTIVE: The purpose of this study was to assess the accuracy of routine T2-weighted MR imaging in detecting and grading articular cartilage lesions in the knee compared with arthroscopy. SUBJECTS AND METHODS: We examined 130 consecutive patients who underwent MR imaging and arthroscopy of the knee for suspected internal derangement. MR imaging consisted of axial and coronal T2-weighted fast spin-echo sequences with fat saturation and sagittal T2-weighted spin-echo sequences. Each single plane was evaluated and graded for the presence and appearance of articular cartilage defects using a standard arthroscopic grading scheme adapted to MR imaging. RESULTS: Of the 86 arthroscopically proven abnormalities, 81 were detected on MR imaging. Sensitivity of the T2-weighted fast spin-echo sequence with fat saturation was 61% for the coronal plane alone and 59% for the axial plane alone. Specificity for each plane was 99%. Sensitivity for the sagittal T2-weighted spin-echo sequence was 40%, and specificity was 100%. Sensitivity of the combination of axial and coronal T2-weighted fast spin-echo sequences with fat saturation and sagittal T2-weighted spin-echo sequence compared with arthroscopy for revealing cartilage lesions was 94%, specificity was 99%, and accuracy was 98%. Sensitivity of coronal and axial T2-weighted fast spin-echo sequences with fat saturation was 93%, and specificity was 99%. Fifty-five lesions (64%) were identically graded on MR imaging and arthroscopy. Seventy-eight lesions (90%) were within one grade using MR imaging and arthroscopy, and 84 lesions (97%) were within two grades using MR imaging and arthroscopy. CONCLUSION: T2-weighted fast spin-echo MR imaging with fat saturation is an accurate and fast technique for detecting and grading articular cartilage defects in the knee. The combination of the axial and coronal planes offers sufficient coverage of articular surfaces to provide a high sensitivity and specificity for chondral defects.     

Primary lung cancer staging: prospective comparative study of MR imaging with CT

Forty-four patients with bronchogenic carcinoma were studied prospectively by both computed tomography (CT) and magnetic resonance (MR) imaging of the thorax during the week preceding thoracotomy. Transaxial MR imaging sequences included T1- and T2-weighted sequences. Coronal and sagittal T1-weighted sequences were added according to tumor location. CT and MR studies were reviewed separately, and the results were compared with surgical and pathologic findings on the basis of TNM classification. No statistically significant differences were found between the two imaging methods for the evaluation of tumor extent or node involvement. T2-weighted sequences did not yield further information on tumor extent or node involvement. Additional imaging planes (coronal or sagittal) appeared useful to study chest wall invasion. Analysis of concordances and discordances did not indicate whether one modality could be substituted for the other, or which diagnostic strategy might be more useful.     

Indirect MR arthrography of the unexercised glenohumeral joint in patients with rotator cuff tears.

RATIONALE AND OBJECTIVES: To evaluate the diagnostic utility of indirect MR arthrography of the unexercised glenohumeral joint in patients with rotator cuff tears confirmed by arthroscopy or arthrotomy as the gold standard. METHODS: Twenty-six patients underwent conventional MR imaging and indirect MR arthrography of the stationary glenohumeral joint using a wrap-around surface coil. Unenhanced T1-weighted spin echo/T2-weighted fast spin echo sequences and T1-weighted gradient echo sequences, adding spectral fat suppression after intravenous administration of contrast medium, were performed in the oblique coronal and oblique sagittal planes. Images were analyzed by three experienced radiologists in consensus. Levels of diagnostic confidence were evaluated using a four-point scale of diagnostic certainty. RESULTS: Performing indirect MR arthrography of the unexercised shoulder leads to a diagnostically efficient enhancement of joint fluid (120% at 4 minutes and 145% at 8 minutes after intravenous injection of gadodiamide). In terms of soft tissue delineation, characterization of rotator cuff tears was significantly improved by using enhanced fat-suppressed T1-weighted gradient echo sequences compared with conventional MR imaging. CONCLUSIONS: Indirect MR arthrography without glenohumeral joint exercise in the diagnosis of rotator cuff tears is feasible and represents a more convenient and less time-consuming alternative to indirect MR arthrography after joint exercise.     

Dynamic gadolinium-enhanced MR imaging of pituitary adenomas: usefulness of sequential sagittal and coronal plane images

Dynamic magnetic resonance (MR) imaging for pituitary adenomas is usually performed in a coronal direction; however, small lesions between slices, or lesions located at the anterior or posterior aspect of the pituitary gland might be overlooked on MR images in only the coronal direction. The purpose of our study was to evaluate whether consecutive dynamic MR images in the coronal and sagittal planes improve detection of pituitary adenomas. Eighteen patients with pituitary microadenomas and nine with healthy pituitary glands were included in this study. MR images were performed with 1.5 T superconductive units and commercially-available head coils. After a 5 ml gadolinium contrast injection, eight serial dynamic sagittal images were obtained. Within 3 or 6 min, this was followed by a 10-15 ml gadolinium injection and acquisition of eight serial dynamic coronal images. Dynamic MR images and conventional noncontrast- and contrast-enhanced sagittal and coronal T1-weighted images were evaluated independently in a blind fashion by two neuroradiologists regarding the depiction of pituitary microadenomas. The sensitivities of dynamic enhanced MR imaging in the detection of microadenomas were 61.1% in sagittal direction, 72.2% in coronal direction respectively, and were superior to those of conventional noncontrast- and contrast-enhanced T1-weighted imaging (22.2-50%). The sensitivity of a combination of sagittal and coronal dynamic enhanced MR imaging for the detection of microadenomas was 88.9% and was superior to those of conventional noncontrast- and contrast-enhanced T1-weighted imaging combining sagittal and coronal directions (61.1%, 61.1%) (P<0.05, P<0.05, respectively). The specificity and accuracy of dynamic enhanced MR imaging with combination of sagittal and coronal images was 88.9% respectively. Dynamic gadolinium-enhanced MR imaging, especially using both sagittal and coronal planes, was concluded to be useful for the detection of pituitary microadenomas.     

Ankle: surface coil MR imaging at 1.5 T

High-field surface coil magnetic resonance (MR) images were obtained of 12 ankles: two from healthy volunteers, seven from patients, and three from fresh cadavers. The cadaver ankles were sectioned in the coronal, sagittal, and axial planes for direct comparison with the MR images. Plain film confirmation of pathologic conditions was obtained in all patients, and five underwent arthroscopy or surgery, or both. MR imaging provided excellent delineation of ligaments and cartilaginous structures in all cases.     

Antero-posterior lesions of the superior glenoid labrum. Magnetic resonance evaluation

PURPOSE: To assess MR potentials in the evaluation of superior glenoid labrum disease and possible associated conditions of the rotator cuff and of the anterior mechanism of the shoulder. MATERIAL AND METHODS: We retrospectively evaluated 51 patients (age range 18 to 53 years) with a diagnosis of anteroposterior lesion of the superior glenoid labrum. MR examinations were performed with a 0.2 T permanent magnet and a dedicated coil, using T1- and T2-weighted SE sequences on mostly coronal-oblique planes. Slice thickness was 4 mm. In 8 cases, the examination was completed with intra-articular injection of contrast agent. Twenty-eight patients were submitted to surgery (arthrotomy in 7 cases; arthroscopy in 21 cases). RESULTS: We considered only the cases with surgical confirmation and divided them into 2 groups: 15 patients with isolated alteration of the superior glenoid labrum and 13 patients with an anteroposterior lesion of the glenoid labrum associated with disease of the rotator cuff or of the anterior mechanism of the shoulder. MRI demonstrated 5 cases of superior labrum irregularities at the level of its glenoid insertional portion (type I lesion); 6 cases of detachment of the superior portion of the labrum (type II); 9 cases of bucket handle tear of the superior labrum with involvement of the insertional portion of the long head of the biceps tendon (type III); 8 cases of superior labrum tear extending within the long head of the biceps tendon (type IV). In the patients with associated disease MRI demonstrated supraspinatus tendon tear in 5 cases, lesion of the labrum also in its anteroinferior portion in 1 case, Hill-Sachs intraspongious fracture with involvement of the inferior glenohumeral complex in 1 case, and complete tear of the rotator cuff in 7 cases. Subsequent surgery always confirmed the presence of associated lesions, while the superior labrum lesion was not confirmed in 3 patients. In 4 cases, surgical findings provided a different classification of the lesion type than MRI. DISCUSSION: In the presence of a type I anteroposterior lesion of the superior glenoid labrum, coronal MRI can depict the loss of the triangular shape of the labrum. Type II lesions show detachment of the labrum, which appears on the MR images as a high signal intensity band passing through the labrum with caudocranial orientation. A superior glenoid labrum tear with a low signal intensity area within the joint indicates a type III lesion. Complete tear of the superior glenoid labrum with involvement of the long head of the biceps tendon demonstrated on the coronal T1-weighted SE and T2-weighted GE sequences is a sign of a type IV lesion. CONCLUSIONS: MRI can be a valuable diagnostic technique in type III and IV lesions of the superior glenoid labrum. It often provides important information about the possible presence of associated diseases, especially of the rotator cuff, which are helpful for treatment planning.     

肩关节磁共振成像扫描技术的临床应用

目的 探讨磁共振成像扫描技术在肩关节疾病诊断和鉴别诊断中的应用价值。方法 本组39例病例(男22例,女17例),应用GP FLEX柔韧线圈作肩关节磁共振成像检查,取横轴位、斜冠状位、斜矢状位三个位置采集,扫描范围包括肱骨头和整个关节盂。扫描序列为自旋回波及快速自旋回波。结果 39例肩关节磁共振成像扫描发现：肩袖撕裂,肩关节骨折,肩周炎,肿瘤,关节积液,腱鞘炎等。结论 肩关节磁共振成像因有较好的分辨力和优良的软组织对比性,以及能多平面成像,可直接显示肩袖损伤及相关的病理改变,对肩关节疾病的诊断和鉴别诊断有较高的应用价值。     

Usefulness of the simultaneous acquisition of spatial harmonics technique during MRI of the shoulder

OBJECTIVE: The simultaneous acquisition of spatial harmonics (SMASH) technique is a parallel imaging technique that uses fewer echoes than conventional techniques to obtain the desired resolution. Production of images occurs more quickly with parallel imaging than with conventional imaging. This study assesses the usefulness of the SMASH technique for MRI of the shoulder. SUBJECTS AND METHODS. Five experienced musculoskeletal radiologists prospectively interpreted MRIs of the shoulder in 50 consecutive patients. All patients underwent a complete MRI examination of the shoulder on a 1.5-T commercially available scanner. Axial fat-saturated proton density-weighted, coronal T1-weighted, and coronal and sagittal fat-saturated T2-weighted sequences were performed. Patients also underwent SMASH T2-weighted imaging in the coronal and sagittal planes. Coronal and sagittal SMASH T2-weighted imaging took approximately 50% as long to complete compared with conventional T2-weighted imaging. Each radiologist interpreted MRIs of the shoulder without knowing whether the images were obtained using the SMASH or the fat-saturated T2-weighted technique. Twenty-eight of the 50 patients also underwent subsequent arthroscopy, and the results were compared with MRI interpretations based on SMASH and fat-saturated T2-weighted images. RESULTS: We found no intraobserver variability between the interpretations of SMASH imaging and the interpretations of fat-saturated T2-weighted imaging. Of the 28 patients who also underwent subsequent arthroscopy, 19 were found to have full-thickness supraspinatus tendon tears and nine had superior labral anterior-to-posterior lesions. All arthroscopic findings correlated with prospective MRI interpretations. CONCLUSION: SMASH imaging allows significant time savings compared with fat-saturated T2-weighted MRI. We found that the use of the SMASH technique did not affect the MRI interpretation or the clinical outcome of patients.     

Magnetic resonance diagnosis of traumatic penile fracture

PURPOSE: To report our experience with MRI in the preoperative evaluation of patients with traumatic penile fractures. MATERIALS AND METHODS: Between January 1998 and December 2001, we performed MRI examinations on five patients (aged 29-48 years; mean age 40 years) with suspected traumatic fracture of the penis occurred during sexual intercourse. In all cases, T1-weighted SE, T2-weighted FSE and GRE sequences in the axial, coronal and sagittal planes were acquired. The study was performed without IV administration of paramagnetic contrast agents and in conditions of detumescence. A small-sized surface coil was used in four cases and a body coil was used in one case. All patients had suspected penile fracture with indications for surgical repair. The MR examination was performed within 12 to 48 hours of the trauma and was requested to aid surgical planning. RESULTS: The MR image quality was adequate in all cases. The examination documented unilateral rupture of the corpus cavernosum in all patients. This finding was associated with haematoma located both subcutaneously and inside the corpus cavernosum itself. In no case was there rupture of both corpora cavernosa. In only one patient was there a suspicion of injuries to the urethral corpus spongiosum, which was confirmed by surgery along with the other MR findings. DISCUSSION AND CONCLUSIONS: Many imaging methods are available to evaluate traumatic penile lesions: ultrasound, colour-Doppler ultrasound, urethrography, cavernosography, angiography and MRI. In agreement with the literature, our experience shows that MRI is useful in evaluating penile injuries owing to its multiplanar capabilities, its good spatial resolution and its excellent tissue contrast resolution. These characteristics enabled a more adequate surgical approach. In our view, MRI can be regarded as an emerging method to obtain helpful diagnostic information, with no risks for the patient.     

Magnetic resonance for the study of osteosarcoma

The authors report their experience with MR imaging in the study of osteosarcoma. Two main elements were evaluated: signal characteristics and loco-regional staging. Seventy-one patients were studied: 65 of them had central long-bone osteosarcoma, and 6 had telangiectatic long-bone osteosarcoma. T1- and T2-weighted spin-echo sequences were employed and all cases were scanned on 3 planes (sagittal, coronal, and axial). In 28 patients MR imaging was performed both before and after preoperative chemotherapy. The obtained data were compared to surgical and pathological findings. With the exception of the typical signal patterns of quite-osteoblastic osteosarcoma (which presents with low signal on both T1- and T2-weighted sequences), no particular signal features were observed which could help distinguish the different types of osteosarcoma. MR imaging is the method of choice in loco-regional staging for, in our series, it allowed a rational and adequate surgical planning. For this purpose, at least a longitudinal T1- and an axial T2-weighted images are required.     

Normal shoulder: MR imaging

Relatively poor spatial resolution has been obtained in magnetic resonance (MR) imaging of the shoulder because the shoulder can only be placed in the periphery of the magnetic field. The authors have devised an anatomically shaped surface coil that enables MR to demonstrate normal shoulder anatomy in different planes with high spatial resolution. In the axial plane, anatomy analogous to that seen on computed tomographic (CT) scans can be demonstrated. Variations in scapular position (produced by patient positioning) may make reproducibility of sagittal and coronal plane images difficult by changing the relationship of the plane to the shoulder anatomy. Oblique planes, for which the angle is chosen from the axial image, have the advantage of easy reproducibility. Obliquely oriented structures and relationships are best seen in oblique plane images and can be evaluated in detail.     

Diagnosis of partial and complete rotator cuff tears using combined gradient echo and spin echo imaging

Most magnetic resonance (MR) studies evaluating the rotator cuff for tears have used T2-weighted imaging in the coronal oblique and sagittal oblique planes, T2^*-weighted gradient echo imaging, however, has advantages over spin echo imaging, including contiguous slices without cross-talk, high contrast around the cuff, and intrinsically shorter imaging times which can be used to increase the number of signals averaged and thus improve the signal-to-noise ratio. We reviewed the shoulder MR scans of 87 consecutive patients who underwent both a MR scan and a shoulder arthroscopy during which the size of tears, if present, was graded. The reviewers were blinded as to the history and arthroscopic results. The MR scans included oblique coronal T2^*-weighted gradient echo and oblique sagittal T2-weighted spin echo images. MR cuff grades were correlated with arthroscopic findings. For complete tears, the sensitivity of MR was 0.91 and the specificity 0.95. For partial tears, the sensitivity was 0.74 and the specificity 0.87. This accuracy is similar to two-plane T2-weighted imaging as previously reported in the literature. There was a statistically significant correlation (p < 0.0005) between the cuff grade as determined by MR and the arthroscopic findings.     

Evaluation of radial-sequence imaging in detecting acetabular labral tears at hip MR arthrography

Objective In recent years, radial imaging has been advocated for improved visualization of the acetabular labrum in magnetic resonance arthrography of the hip. The purpose of this study was to investigate whether radial imaging demonstrates labral tears not visible on standard imaging planes. Methods Fifty-four consecutive magnetic resonance (MR) arthrograms of the hip that included radial imaging over 2 years were retrospectively analyzed by two radiologists. Standard imaging planes and radial imaging were reviewed for identification of labral tears in four specific areas of the labrum: anterosuperior, posterosuperior, anteroinferior, and posteroinferior. The standard imaging sequences include fat-saturated spin-echo T1-weighted images in the coronal and oblique axial planes, non-fat-saturated T1-weighted images in the coronal and sagittal planes, and T2-weighted sequence in the axial plane. Radial imaging was performed as previously described using fat-saturated T1-weighted sequences. Results Using standard imaging planes, 50 anterosuperior, 31 posterosuperior, 10 anteroinferior, and 9 posteroinferior labral tears were detected in 54 MR arthrograms of the hip. Using radial sequences alone, 44 anterosuperior, 25 posterosuperior, 9 anteroinferior, and 5 posteroinferior labral tears were detected. In all four areas of the labrum, the radial imaging did not show any labral tear not seen on standard imaging planes. Discussion In MR arthrography of the hip, radial imaging did not reveal any additional labral tears. Standard imaging planes sufficiently demonstrate all acetabular labral tears.     

Pituitary adenomas: high-resolution MR imaging at 1.5 T

The magnetic resonance (MR) images of 28 patients with surgically confirmed pituitary adenomas were retrospectively evaluated. The examinations were performed on a 1.5-T superconducting MR system using a multisection spin-echo technique with 3-mm-thick sections and a 256 X 256 matrix. T1- and T2-weighted images were obtained in sagittal and coronal planes. The MR findings were correlated with detailed operative reports and diagrams. There were 11 microadenomas and 17 macroadenomas. Ten of the microadenomas and all of the macroadenomas were accurately localized and their extent delineated, particularly on T1-weighted coronal sections. Adenomas typically appeared hypointense on T1-weighted coronal sections. The appearance on T2-weighted images was variable, and generally the lesions were less well seen. Involvement of parasellar structures, particularly the optic chiasm and cavernous sinuses, was accurately depicted. Cyst formation and hemorrhage could be characterized in some instances. In general, there was excellent correlation between MR imaging and operative findings.     

The anterior glenohumeral joint capsule: macroscopic and MRI anatomy of the <Emphasis Type="Italic">fasciculus obliquus</Emphasis> or so-called <Emphasis Type="Italic">ligamentum glenohumerale spirale</Emphasis>

The purpose of this study was to demonstrate the macroscopic and MRI anatomy of the fasciculus obliquus, otherwise known as the ligamentum glenohumerale spirale or spiral GHL of the anterior shoulder joint capsule. Conventional and MR arthrography (1.5-T device Somatom Symphony, Siemens with shoulder coil) images in standard planes were compared with gross anatomic dissection findings in six fresh shoulder specimens from three cadavers. The MR imaging protocol included T1, PD and DESS 3D WI sequences. The macroscopically recognisable band—the spiral GHL—was identified by anatomic dissection and MRI in all the specimens. It was best visualised by MR arthrography on axial and oblique sagittal planes (T1; PD WI) and appeared as a low signal intensity stripe within the superficial layer of the anterior joint capsule. The absence of the variable middle glenohumeral ligament did not influence the anatomic properties and the MR imaging of the spiral GHL. Diagnostic visualisation of the normal anatomic structures is a prerequisite to distinguish between normal and pathologic conditions. Anatomy of the spiral GHL can be used by radiologists for more detailed interpretation of the anterior shoulder joint capsule ligaments on MR images.     

Fibro-cartilaginous lesions of the glenoid labrum in shoulder instability: a proposed classification using sagittal-oblique arthro-MRI

PURPOSE: To propose a graded classification of lesions of the fibrocartilaginous glenoid labrum in traumatic dislocations of the shoulder, based on arthro-MRI in sagittal-oblique views. MATERIALS AND METHODS: Seventy-one patients with histories of chronic post-traumatic shoulder instability were studied from May 2000 to May 2001. MR images were obtained using superconducting magnets operating at 1 and 1.5 Tesla, with a dedicated shoulder coil. The study was carried out in combination with arthrography, with axial sections oriented perpendicularly to the longitudinal axis of the glena, oblique coronal sections parallel to the course of the supraspinous muscle tendon and oblique sagittal sections with axis parallel to the longitudinal axis of the glena. RESULTS: In one case an anatomical variant was found (Buford complex). In 18 patients a simple fissuration of the fibrocartilaginous glenoid labrum was found, whereas 28 patients displayed more extensive lesions affecting the middle-inferior portions of the labrum. In 15 patients the lesion extended to the middle-superior third of the glena, involving the middle glenohumeral ligament. In 9 cases, in addition to a complete lesion of the labrum, with typical "bucket-handle" appearance, a lesion of the superior and middle glenohumeral ligaments was also observed. DISCUSSION AND CONCLUSIONS: In traumatic shoulder dislocations it is essential to provide the surgeon with precise information regarding the location, extension and degree of damage to the capsule, ligaments and especially the labrum of the glenohumeral joint. On the basis of the results obtained in the sagittal-oblique sections we propose an MR-arthrography classification dividing lesions of the fibrocartilaginous labrum into 4 grades.     

MR imaging of the temporomandibular joint: a cadaver study of the value of coronal images

Recent studies comparing cryosectional anatomy of the temporomandibular joint (TMJ) to its MR appearance have shown that the assessment of disk displacement is inaccurate when based on the sagittal plane alone. This article describes the MR appearance of the normal and abnormal (positional and osseous changes) TMJ in the coronal plane and compares these findings with their cryosectional anatomy. Twenty-two TMJs from unselected frozen cadavers were embedded in paraffin. Coronal and sagittal MR imaging was performed; specimens were then cut in the same plane as the coronal images. Disk position by cryosection was normal in 14 cases and abnormal in eight cases. Coronal MR images alone correctly depicted the TMJ disk position in 17 cases (77%) (13 normal, four abnormal). Complementary sagittal images were necessary for diagnosing anterior displacement in two cases (9%). MR was inaccurate in three cases (14%) of severe degenerative joint disease. Bone condition was correctly diagnosed on the basis of coronal images alone in all cases. Our study shows that coronal MR imaging alone of the TMJ in cadavers accurately shows disk position in 77% of cases. Complementary sagittal images were of benefit in the diagnosis of an additional 9% with anterior displacement. Disk position was assessed inaccurately in either plane in patients with severe degenerative joint disease. For a full MR assessment of the TMJ for disk position and bone condition, we recommend imaging in both coronal and sagittal planes.     

Pelvic abnormalities in children: assessment with MR imaging

Multiplanar images of 62 pelvic lesions in 58 children and adolescents (aged 7 months to 19 years; mean, 10.6 years) were obtained with 0.3-T magnetic resonance (MR) imaging. Lesions were divided into three categories: congenital anomalies, cystic lesions and fluid collections, and neoplasms. MR demonstrated lesions well in all categories. Midline lesions were best imaged sagittally, and lesions of paired structures, axially. The coronal plane was useful in evaluating the superoinferior extent of lesions and in defining the extent of lymphadenopathy. T1-weighted sequences were sufficient to depict most congenital and cystic lesions. T2-weighted sequences were useful in demonstrating the extent of neoplasms and the position of ectopic gonads. Ultrasonography (US) was also performed in 45 cases. MR and US delineated lesions equally well in 25 cases (55.5%), MR was superior in 19 (42.4%), and US was superior in one (2.2%). Computed tomography (CT) was performed in 13 cases. MR and CT delineated lesions equally well in eight cases (61.5%), MR was superior in four (30.8%), and CT was superior in one (7.7%).