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Biomedical subjects

H M Fritts

Publications and source records attributed to H M Fritts.

At least 19 recordsLinked to original sources

Evaluation of the rotator cuff and glenoid labrum using a 0.2-Tesla extremity magnetic resonance (MR) system: MR results compared to surgical findings.

The purpose of this investigation was to evaluate the diagnostic capabilities of magnetic resonance imaging (MRI) performed using a dedicated-extremity MR system in detecting lesions of the rotator cuff and glenoid labrum. This retrospective study compared the MR results obtained in 47 patients that underwent MRI using a 0.2-Tesla extremity MR system (E-scan) to the surgical findings. MR images of the shoulder were obtained as follows: shoulder coil, T1-weighted, coronal-oblique and axial images; short Tau inversion recovery (STIR), coronal-oblique images; and T2-weighted, coronal-oblique, sagittal-oblique, and axial images. The MR examinations were interpreted by three highly experienced, musculoskeletal radiologists. Open surgical (N = 26) or arthroscopic (N = 21) procedures were performed within a mean time of 33 days after MRI. The surgical findings revealed rotator cuff tears in 28 patients and labral lesions in 9 patients. For the rotator cuff tears, the sensitivity, specificity, positive predictive value, and negative predictive value were 89%, 100%, 100%, and 90%, respectively. For the labral lesions, the sensitivity, specificity, positive predictive value, and negative predictive value were 89%, 95%, 80%, and 97%, respectively. The findings indicated that there was good agreement comparing the MR results obtained using the low-field extremity MR system to the surgical findings for determination of lesions of the rotator cuff and glenoid labrum. Notably, the statistical values determined for the use of this MR system were comparable to those reported in the peer-reviewed literature for the use of whole-body, mid- and high-field-strength MR systems.

Adolescent↗

MR imaging of the spine in sports injuries.

MR imaging has afforded an ability to better visualize and characterize a whole host of spine abnormalities encountered in the athletic population. It remains the mainstay in the noninvasive diagnosis of most soft-tissue abnormalities occurring within and about the spine. Its role in the evaluation of central spinal stenosis, the central spinal canal, and the spinal cord is unsurpassed by other noninvasive imaging modalities. In the setting of underlying fractures, it is complementary to CT, particularly with respect to evaluating concomitant soft-tissue and ligamentous abnormalities. With its ability to image edema and reactive marrow changes, it is useful in the evaluation of osseous stress changes that may occur in the athletic population.

Athletic Injuries↗

MR imaging of the shoulder after an impingement test: how long to wait.

OBJECTIVE: The purpose of this study was to determine the appropriate minimum waiting time between an impingement test with subacromial injection and subsequent MR imaging to avoid misinterpretation if the injected fluid is still present. CONCLUSION: MR imaging should be delayed a minimum of 24 hr after a subacromial injection. Fluid in the subacromial space 24 hr after subacromial injection is unrelated to an impingement test.

Adult↗

Magnetic resonance imaging of the musculoskeletal system: the spine.

Magnetic resonance imaging in the patient who has had surgery is discussed. The most common indication for postoperative imaging is in the distinction between postoperative fibrosis and recurrent disc herniation. Magnetic resonance imaging is invaluable in the assessment of potential causes of failed back surgery syndrome such as postoperative infection, arachnoiditis and adjacent segment degeneration. Magnetic resonance imaging assumes a less important role in postoperative patients with metal hardware owing to image degradation secondary to metal artifact. Magnetic resonance imaging has a complementary role with computed tomography evaluation of spinal trauma. It excels at the noninvasive evaluation of spinal deformities and neoplasms.

Arachnoiditis↗

Magnetic resonance imaging of the musculoskeletal system. Part 8. The spine, section 1.

Magnetic resonance has assumed a preeminent role in the imaging evaluation of the spine. Owing to its multiplanar capability and superior soft tissue contrast, magnetic resonance imaging is the procedure of choice for a host of spinal disorders including degenerative disc disease, tumor evaluation, trauma, and spinal deformities. It represents the most accurate means of distinguishing between recurrent disc herniation and epidural fibrosis, and it excels at the assessment of many postoperative abnormalities such as infection, adjacent segment disc degeneration, and arachnoiditis. Magnetic resonance imaging is also helpful in the evaluation of numerous diagnostic challenges that are less well resolved by other means. This includes the distinction between disc herniation and epidural hematoma, synovial cyst from nonspecific fibrous thickening of a facet capsule, and the evaluation of numerous other soft tissue abnormalities. Computed tomography, computed tomography myelography, and scintigraphy continue to be useful for numerous specific disorders and in those patients with metal hardware or contraindications to magnetic resonance scanning. Overall, however, magnetic resonance is the imaging procedure preferred for many spinal disorders. This article is the first installment of a 3-part series discussing the role of magnetic resonance imaging of spinal disorders. Section 1 will describe the varying imaging modalities available and their relative advantages and disadvantages. A consideration of magnetic resonance imaging techniques will follow, followed by a discussion of the imaging manifestations of early degenerative disc disease. Section 2 will be devoted to an in depth discussion of specific pathologic processes encountered in patients with degenerative disc disease. Section 3 will end the series with a consideration of postoperative imaging followed by a discussion of spinal deformities, trauma, and neoplasms.

Bone Marrow↗

Magnetic resonance imaging of the musculoskeletal system. Part 8. The spine, section 2.

Magnetic resonance imaging has revolutionized the noninvasive evaluation of degenerative disc disease and its complications. Compared with computed tomography and computed tomographic myelography, magnetic resonance allows specific determination of the nature of disc protrusions and other degenerative related soft tissues about the spine. Magnetic resonance offers the most complete evaluation of specific degenerative disorders including degenerative facet disease, spondylolysis, spondylolisthesis, spontaneous lumbar epidural hematomas, and juvenile discogenic disease.

Hematoma, Epidural, Cranial↗

Chronically injured posterior cruciate ligament: magnetic resonance imaging.

Magnetic resonance imaging has been said to be highly reliable for diagnosis of acute posterior cruciate ligament insufficiency. In the present study, 13 patients whose posterior cruciate ligament insufficiency had been documented by magnetic resonance imaging within 10 weeks of the acute injury were recalled for a followup examination and magnetic resonance imaging. The followup interval ranged from 5 months to 4 years. In only 23% of the cases did the posterior cruciate ligament still appear discontinuous on followup magnetic resonance imaging. In the remaining 77%, the posterior cruciate ligament was continuous from tibia to femur, although it appeared abnormally arcuate or hyperbuckled. Conventional interpretation of these magnetic resonance images would suggest that the posterior cruciate ligament had healed. Nevertheless, by clinical examination results, these same patients all were judged to have posterior cruciate ligament insufficiency. Thus, it was concluded that although magnetic resonance imaging may be reliable for evaluation of acute posterior cruciate ligament injury, magnetic resonance imaging findings should not be used to infer functional status in chronic cases.

Chronic Disease↗

Occult osseous lesions associated with anterior cruciate ligament tears.

Occult osseous lesions occurring with anterior cruciate ligament tears have been described only recently. Twenty patients with complete anterior cruciate ligament disruptions and evidence of occult osseous lesions on their preoperative magnetic resonance (MR) images were evaluated retrospectively at 24- to 73-months' followup to document the natural history and long-term effects of the lesions. Thirty-seven initial osseous signal abnormalities were documented on the MR images of 20 patients. All 20 patients had lesions in the posterolateral tibial plateau, and 13 had additional lesions in the lateral femoral condyle. Twenty-four of the 37 osseous lesions appeared resolved on followup MR images, and 13 had become sclerotic. Lesions of the lateral tibial plateau were especially likely to be sclerotic at followup. This study reaffirms the specificity of bone signal abnormalities of the posterolateral tibial plateau and lateral femoral condyle in association with complete anterior cruciate ligament tears. The data indicate that a proportion of anterior cruciate ligament patients will incur progressive articular cartilage abnormalities, although case-by-case predictions based on initial MR images would be unreliable.

Adult↗

[Evaluation of the rotator cuff with magnetic tomography].

Rotator cuff tears are difficult to diagnose clinically, both in the acute and the chronic phase. Both conservative and surgical treatment give the best results if the injury is detected early. Magnetic resonance imaging (MRI) has recently been introduced for diagnoses of cuff tears. The purpose of this study was to establish the accuracy of MRI in relation to surgical findings in the same patient group. MRI was used in the diagnosis of 25 patients who later underwent surgery for injury to the rotator cuff. During the surgery, 19 total tears were identified, of which 15 had been described by MRI. MRI showed a sensitivity of 79% and a specificity of 83%. The predictive value of a positive test was 83%. In experienced hands, MRI is extremely accurate for detecting rotator cuff injuries, but ultrasonography should still be the first method of diagnosis in Norway, because of its accuracy when used by experienced practitioners, and its availability and low cost.

Adult↗

MRI of the shoulder.

MRI of the shoulder is widely considered the imaging modality of choice in the evaluation of shoulder pain and the clinical impingement syndrome. This is because of its direct evaluation of all of the soft tissue structures of the subacromial space, as well as its ability to depict the relationship of the overlying osseous and soft tissue structures of the coracoacromial arch. It also provides information regarding the capsulolabral anatomy and, with the addition of MR arthrography, is becoming recognized as the imaging modality of choice for instability workup. MRI evaluation, when combined with the always important clinical history, physical examination, and radiographs, provides the referring clinician and orthopedic surgeon with the most anatomic and pathological information possible. This, in turn, allows the most informed decision making possible regarding conservative management or surgical treatment.

Humans↗

Radial tears of the menisci: MR findings.

Radial meniscal tears have a plane of cleavage oriented across the short axis of the meniscus in the same plane in which radial images are oriented. These tears are important to recognize, because they have clinical implications different from those of other meniscal tears with respect to meniscal function, orthopedic treatment, and clinical course. Depending on their size, location, and orientation, radial tears can have different appearances on standard MR images. Certain types can be fairly subtle to diagnose. The purpose of this essay is to illustrate the varied appearances of radial tears on MR images and the findings commonly associated with radial tears.

Humans↗

MRI findings of acute turf toe. A case report and review of anatomy.

Normal anatomy of the metatarsophalangeal joint of the hallux has been well described. However, the pathologic anatomy of turf toe, a common injury among football and rugby players, has not been documented in detail. Magnetic resonance images (MRI) of a classic case of turf toe were examined and the findings were compared with MRI of a normal specimen and correlated with known features of gross anatomy. MRI findings confirmed that turf toe involves a sprain or tear of the plantar metatarsophalangeal joint capsule.

Adult↗

Osteochondral lesions and cruciate ligament injuries. MRI in 18 knees.

Magnetic resonance images were obtained prior to arthroscopy and surgery in 18 knees with acute anterior cruciate ligament injury. The incidence of osseous lesions was assessed and the findings were compared with those at arthroscopy. A total of 28 osseous lesions were detected by MRI in 15 knees, but none of these were detected by radiographs or arthroscopy.

Adolescent↗

Diagnosis of meniscal and cruciate ligament tears using MRI. Evaluation of two scanning techniques.

The accurate diagnosis of meniscal and cruciate ligament tears is essential for proper management of knee injuries. In recent years, magnetic resonance imaging has been increasingly used to diagnose knee pathology. Several articles have documented the accuracy of MRI, but conflicting results have been reported. We present a series of 50 consecutive patients who underwent both MRI and complete arthroscopy. We tested two different scanning protocols and found the higher-resolution scanning protocol to be more accurate, resulting in fewer discrepancies between the results of MRI and arthroscopy, which we used as the standard for comparing the MRI interpretations. Magnetic resonance imaging is an important diagnostic tool in orthopedic practice. It is available, accurate, and well-accepted by patients. However, as demonstrated by the results of this study, the accuracy of MRI is highly dependent upon the scanning protocol used.

Adolescent↗

MR of osteochondritis dissecans and avascular necrosis of the mandibular condyle.

We studied 40 patients exhibiting radiologic changes of either osteochondritis dissecans (OCD) or avascular necrosis (AVN) involving the mandibular condyle to evaluate the structural changes associated with these lesions when using high-field-strength MR imaging. Various clinical indications for imaging each patient with routine radiography, tomography, and surface-coil MR included headache, temporomandibular joint (TMJ) and/or ilsilateral facial pain, joint crepitus, clicking, locking, and either recently acquired or changing (unstable) occlusal disorder. Radiologic findings included alterations in condyle morphology and MR signal characteristics compatible with either OCD or AVN or, in some cases, both. Previous nonsurgical mandibular trauma was temporally related to the onset of symptoms in eight patients. Five patients exhibiting either unilateral or bilateral AVN involving the condyles and condylar necks had undergone previous orthognathic surgery, including sagittal split mandibular osteotomies followed by intermaxillary fixation. One patient exhibiting condylar AVN with articular surface collapse and osseous destruction had undergone previous TMJ meniscectomy followed by insertion of a permanent Proplast implant. Thirty-one of 34 patients with no prior surgery and MR changes of condylar OCD/AVN had associated internal derangement of the TMJ meniscus. There was surgical confirmation of findings in 10 joints. We assert that OCD and AVN are relatively common, clinically significant lesions of the mandibular condyle often associated with preexisting internal derangement of the temporomandibular joint.

Adolescent↗

Three-dimensional computed tomography in maxillofacial surgical planning.

Fifty-four maxillofacial three-dimensional computed tomographic examinations were performed during a 12-month period for the purpose of surgical planning. Pathologic entities in the series included trauma, neoplasia, cleft palate, and other developmental anomalies. Computer-assisted mandibular disarticulation was performed routinely after each study to permit direct viewing of the mandible or maxilla in isolation. Three-dimensional computed tomography is a useful technique for maxillofacial surgical planning.

Adolescent↗

Temporomandibular joint: MR imaging of internal derangements and postoperative changes.

Nineteen abnormal temporomandibular joints (TMJs) imaged with high-field-strength surface-coil MR are presented to illustrate specific changes associated with disk derangement, trauma, and previous surgery. Cases were selected from a series of 248 TMJ MR studies in 144 patients (9-68 year old, 130 females and 14 males) performed during a 5-month period. Surgical findings were available for correlation in 44 of the 248 joints studied. Increased signal caused by myxoid degeneration within the degenerating meniscus was seen, as were pathologic changes including atrophy, fibrosis, and contracture of masticatory muscles occurring with internal derangements. Advantages and limitations of MR are discussed with reference to arthrography and videofluoroscopy. High-resolution and partial-flip-angle images of a normal joint are provided for comparison. In most clinical circumstances, MR is the procedure of choice when examining the TMJ, because it provides contrast resolution of soft-tissue structures superior to that of conventional imaging techniques.

Female↗