David J. Sartoris

Pigmented villonodular synovitis: MRI characteristics

The magnetic resonance imaging (MRI) scans of 26 patients with histopathologically proven pigmented villonodular synovitis (PVNS), involving joints but excluding tendon sheaths, were reviewed retrospectively. The purpose of this study is to define the spectrum and frequency of MRI characteristics for PVNS using conventional spin echo (in two cases before and after intravenous administration of gadopentate dimeglumine) and also gradient echo techniques. A cystic variety is presented, the MRI appearances of which have not been found in a review of the literature.

The Effect of Arthroscopic Surgical Lysis and Lavage of the Superior Joint Space on TMJ Disc Position and Mobility

The effect of arthroscopic release of temporomandibular joint (TMJ) discs was prospectively studied using a combination of preoperative tomograms, magnetic resonance imaging (MRI) scans and arthrograms, and postoperative MRI scans. Of 92 patients studied, 60 had bilateral and 32 had unilateral joint disease. All of the 152 joints studied had anterior disc displacement preoperatively. Postoperative MRI scans revealed that 92% of the patients had persistent anterior disc displacement, although 80% of the patients did have marked improvement of disc mobility. Ninety-two percent of the total patient sample had a significant reduction in pain and restoration of normal mandibular function.

Fibrolipomatous hamartoma : MR imaging findings

ObjectiveTo analyze the MR imaging features of fibrolipomatous hamartoma (FLH) of nerves.Design and patientsMR imaging studies from six patients (three men and three women) were retrospectively reviewed by three musculo-skeletal radiologists. In four patients, a biopsy of the nerve lesion was performed. In two patients, biopsy data were unavailable and the diagnosis was based on the clinical history combined with the MR imaging findings.Results and conclusionMR imaging demonstrated fusiform nerve enlargement that was caused by fatty proliferation and thickening of nerve bundles. Nerve bundles appeared as serpentine tubular structures, hypoin-tense on both T1- and T2-weighted images. The degree of fatty proliferation varied among patients. In addition, significant variation in the distribution of fat along the course of the nerves was noted. In three patients, FLH followed the branching pattern of the nerves, a characteristic pathologic finding. In two patients, intramuscular fat deposition (biceps and tibialis posterior muscles) was present. MR imaging findings of FLH are typical, allowing a confident diagnosis. The variation of fatty proliferation among patients and involved nerves as well as the tendency of the abnormalities to follow the branching pattern of the nerves is well demonstrated with MR imaging. FLH may present as an isolated nerve lesion, may be associated with intramuscular fat deposition, or may occur as a feature of macrodystrophia lipomatosa (MDL).

Femoral anteversion and neck-shaft angle in children with cerebral palsy.

A database of femoral anteversion and neck-shaft angle was compiled of measurements made by the trigonometric fluoroscopic method of 147 patients (267 hips) with cerebral palsy. The angles of femoral anteversion were similar at early ages between healthy children and children with cerebral palsy. However, as the age of the children increased, those with cerebral palsy showed little change in anteversion angle, whereas the healthy children had progressively decreasing angles of femoral anteversion as they approached adulthood. The neck-shaft angle was increased significantly in children with cerebral palsy compared with the angles of healthy children. Patients who were ambulatory were shown to have an increased angle of femoral anteversion and a decreased neck-shaft angle compared with nonambulatory patients. There was no significant difference in angles among the various distributions of involvement, including patients with diplegia, hemiplegia, and quadriplegia.

Hand ultrasound for osteoporosis screening in postmenopausal women

Abstract: There is a need for low-cost screening methods to detect low bone mass (osteopenia or osteoporosis) in postmenopausal women. The utility of quantitative ultrasonography (QUS) of the hand was assessed for osteoporosis screening using the WHO criteria. Bone mineral density (BMD) was measured in 206 postmenopausal Mexican-American women at the total hip and lumbar spine by dual-energy X-ray absorptiometry (DXA). The amplitude-dependent speed of sound (AD-SoS) was measured in the phalanges by QUS. Subjects identified by DXA as having osteopenia or osteoporosis had significantly lower AD-SoS values in comparison with normals. Estrogen users had significantly higher spine and hip BMD and AD-SoS values compared with non-estrogen users. The areas under the receiver operating characteristic (ROC) curves (AUC) for AD-SoS to screen for osteoporosis (T-score ≤−2.5) at the spine or hip were 0.73 for all subjects, 0.74 for estrogen users and 0.68 for non-estrogen users. The AUC for non-estrogen users to screen for osteopenia (T-score −1 to −2.5) was 0.77. Performance comparisons of AD-SoS with SCORE (a risk factor questionnaire) and body weight showed AUC values of 0.73, 0.69 and 0.65, respectively. QUS was the superior screening test when considering both the AUC and the shape of the ROC curves. For non-estrogen users, the group at higher risk for osteoporosis, QUS correctly identified 31% as normal, and 62% as having low bone mass and needing DXA referral; and the remaining 7% were false negatives. These data suggest phalangeal QUS can be effectively used for screening osteoporosis in postmenopausal women.

Carpal tunnel volume determination by magnetic resonance imaging three-dimensional reconstruction

Three-dimensional computer reconstruction of magnetic resonance images (MRI) of ten cadaveric specimens was used to determine carpal tunnel volume and carpal arch width. Magnetic resonance images-acquired data were compared with direct measurement of cadaveric carpal canal volume by means of a silicone-injection technique. Mean MRI three-dimensional reconstruction volume was 5.84 ml +/- 1.24 ml. Mean silicone-mold volume was 4.73 +/- 1.01 ml. A correction factor of 0.8161 was used to accurately calculate carpal tunnel volume from MRI-acquired data. There was no significant difference between calculated carpal tunnel volumes and silicone-mold volumes (p = 0.623), and there was a linear relationship between MRI-acquired volumes and silicone-mold volumes (correlation coefficient r = 0.97). Differences in MRI-volume determinations between observers were not significant (0.25 greater than or equal to p greater than 0.1). MRI three-dimensional reconstruction, a valid and reproducible technique for measuring carpal tunnel volume and dimensions, has considerable research potential for the evaluation of the relationship between the carpal canal and its contents before and after carpal tunnel release.

Juxtaacetabular ganglionic (or synovial) cysts: CT and MR features

Radiographic findings include supraacetabular bone erosions, subchondral acetabular cysts, soft tissue masses with or without radiolucent inclusions representing nitrogen gas, joint space narrowing, and abnormal hip configuration. Associated tears of the acetabular labrum were confirmed by arthrography in two patients. Computed tomography and magnetic resonance imaging afforded improved delineation of soft tissue ganglia and their relationship to the acetabular bone, labrum, and hip joint. We report our experience with seven patients in whom various imaging examinations clearly documented the presence of soft tissue cystic lesions adjacent to the acetabulum; in six of the seven patients, significant clinical manifestations were evident in the affected hip. Such cysts, whether designated synovial or ganglionic in type, appear to be a frequently overlooked yet important cause of hip symptomatology.

MR imaging of articular cartilage in the ankle: comparison of available imaging sequences and methods of measurement in cadavers

Abstract Objective. To assess hyaline cartilage of cadaveric ankles using different magnetic resonance (MR) imaging techniques and various methods of measurement. Design and patients. Cartilage thicknesses of the talus and tibia were measured in ten cadaveric ankles by naked eye and by digitized image analysis from MR images of fat-suppressed T1-weighted gradient recalled (FS-SPGR), sequences and pulsed transfer saturation sequences with (FS-STS) and without fat-suppression (STS); these measurements were compared with those derived from direct inspection of cadaveric sections. The accuracy and precision errors were evaluated statistically for each imaging technique as well as measuring method. Contrast-to-noise ratios of cartilage versus joint fluid and marrow were compared for each of the imaging sequences. Results. Statistically, measurements from FS-SPGR images were associated with the smallest estimation error. Precision error of measurements derived from digitized image analysis was found to be smaller than that derived from naked eye measurements. Cartilage thickness measurements in images from STS and FS-STS sequences revealed larger errors in both accuracy and precision. Interobserver variance was larger in naked eye assessment of the cartilage. Contrast-to-noise ratio of cartilage versus joint fluid and marrow was higher with FS-SPGR than with FS-STS or STS sequences. Conclusion. Of the sequences and measurement techniques studied, the FS-SPGR sequence combined with the use of digitized image analysis provides the most accurate method for the assessment of ankle hyaline cartilage.

Hemophilic pseudotumor: spectrum of MR findings

Abstract Objective. To determine the MR imaging appearance of hemophilic pseudotumor (HP) and its clinical implications. Design and patients. Five hemophilic patients (aged 35–77 years) with 12 HPs in various anatomic locations were included in this study. The MR images were retrospectively evaluated for the appearance of the lesions and accompanying abnormalities, as well as their clinical implications. Results and conclusion. MR images of all five patients (12 lesions) showed well-defined masses containing blood clots in various stages of organization surrounded by a fibrous capsule in subcutaneous fat or in intramuscular, interfascial, subperiosteal, and intraosseous locations. Intramuscular HP frequently had mural nodules. This is an almost unique appearance that is somewhat unexpected. MR imaging allowed determination of number, size, and extent of the lesions, evidence of neurovascular involvement, and accompanying musculoskeletal alterations. It is concluded that MR imaging not only is a sensitive and accurate method for detecting and diagnosing HP and providing useful information for therapeutic decision making, but can also be used to assess results of treatment by allowing evaluation of the evolution of blood products, the size of lesions in regions difficult to access by physical examination, and recurrent bleeding within a chronic lesion.

MR findings in asymptomatic shoulders: a blind analysis using symptomatic shoulders as controls

We performed a blind prospective analysis of the shoulders of 20 asymptomatic volunteers, aged 25 to 55 years, to determine the frequency of magnetic resonance (MR) findings considered abnormal in symptomatic patients. Twenty symptomatic patients were used as controls. With regard to the asymptomatic shoulders, all 20 had intact rotator cuff tendons, although six (30%) of the tendons had abnormal internal signal, and one (5%) had abnormal morphology. Subdeltoid and subacromial fat planes were intact in 20 (100%) and 19 (95%) shoulders respectively. Subdeltoid or subacromial fluid was not present in any shoulder. Acromioclavicular osteophytes and supraspinatus depression were seen in seven (35%) and six (30%) respectively. The glenoid labrum was intact in all volunteers, although it had abnormal internal signal in 10 (50%). MR findings of abnormal signal in the glenoid labrum, and of abnormal signal and morphology of the rotator cuff tendons, supraspinatus depression, and acromioclavicular osteophytes have been reported as signs of instability, tendinitis, and impingement. Similar findings were seen in asymptomatic volunteers, indicating that these findings may not be a sign of clinically significant pathology.