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Biomedical subjects

G F Carrera

Publications and source records attributed to G F Carrera.

At least 19 recordsLinked to original sources
PubMed1992

Increased sacroiliac joint uptake after lumbar fusion and/or laminectomy.

Of 753 adult patients undergoing SPECT and planar bone scintigraphy for the evaluation of low back pain, 43 (6%) showed either unilateral or bilateral increased sacroiliac joint (SIJ) uptake. Five of the 58 abnormal joints were only identified with SPECT (9%), whereas 20 of the 58 abnormal joints were much more convincingly demonstrated by SPECT (34%). Fifteen of the 43 patients with increased SIJ uptake had undergone prior lumbar laminectomy and/or spinal fusion. Such spinal surgery can increase impact loading on the SIJ, leading to mechanical overload and sacroiliitis. Degenerative joint disease, trauma, or other benign pathology accounted for the remaining patients with increased SIJ uptake. The authors conclude that for patients with a history of lumbar spinal fusion and/or laminectomy, increased SIJ uptake usually is caused by altered spinal mechanics rather than malignancy or infection.

Adult↗
PubMed1992

High-resolution bone scintigraphy of the adult wrist.

Bony anatomic landmarks of the wrist (e.g., pisiform, hook of hamate, radioulnar joint, and styloid processes of the radius and ulna) were routinely identified in 28 adult patients examined for wrist pain. With the wrists prone and immobilized, bone scintigrams were obtained for 500,000 counts with an asymmetric (133 to 161 keV) Tc-99m energy window and either a converging (best choice) or straight-bore, high-resolution collimator. High-resolution scintigraphy precisely localized degenerative joint disease (nine patients), scaphoid fractures (five), pisiform fracture (one), lunate avascular necrosis (one), radioulnar arthritis (one), septic or inflammatory arthritis (six), ulnocarpal impingement (two), and reflex sympathetic dystrophy syndrome (two). Images obtained palm down with the wrist in ulnar deviation helped identify increased uptake within the scaphoid. Fracture and significant bone or joint disease were excluded in one patient.

Adult↗
PubMed1992

Long bicipital tendon of the shoulder: normal anatomy and pathologic findings on MR imaging.

The tendon of the long head of the biceps muscle (long bicipital tendon) has a complex course from its muscle belly to its insertion onto the supraglenoid tubercle/glenoid labrum. It is stabilized by numerous tendinous and ligamentous structures and is, in turn, partly responsible for maintenance of normal glenohumeral function. In this report we describe the anatomy of this tendon, correlating high-resolution MR images with cryomicrotome sections. We illustrate typical MR findings in pathologic conditions affecting the long bicipital tendon sheath, the substance of the tendon, and finally the tendon position.

Chondromatosis, Synovial↗
PubMed1991

Effect of tendon orientation on MR imaging signal intensity: a manifestation of the "magic angle" phenomenon.

To determine whether orientation in the static field may be responsible for the frequent occurrence of increased signal intensity within normal tendons at magnetic resonance (MR) imaging, seven healthy volunteers were imaged by means of a 1.5-T unit and standard clinical pulse sequences. The wrist, ankle, and shoulder regions were evaluated with local coils. Imaging was performed with tendon orientations ranging from 0 degree to 90 degrees in relation to the constant magnetic induction field (B0). Markedly increased intratendinous signal intensity was observed at the "magic angle" of 55 degrees, intermediate signal intensity was observed at 45 degrees and 65 degrees, and no signal intensity was observed at 0 degree and 90 degrees. Signal intensity was evident only when a short echo time was used. The authors believe that tendon orientation greatly affects tendon signal intensity in vivo. Increased signal intensity due to the magic angle effect may be misdiagnosed as tendinous degeneration, tendinitis, or frank tear.

Ankle Joint↗
PubMed1991

Interdigital (Morton) neuroma: high-resolution MR imaging with a solenoid coil.

Fifteen patients (17 feet) with symptoms suggestive of plantar interdigital neuroma underwent magnetic resonance (MR) imaging at 1.5 T with a solenoid forefoot coil with an 8-cm field of view. Surgery was subsequently performed on six feet. Fifteen interdigital masses were identified with MR imaging. Five of these, in feet that underwent surgery, were pathologically confirmed neuromas. In the remaining foot that underwent surgery, flexor tendon injury with probable inflammatory reaction was demonstrated with MR imaging but was interpreted as indeterminate for neuroma. No neuronal was identified at surgery, which otherwise confirmed the MR imaging findings. Neuromas were most conspicuous on T1-weighted images as foci of decreased signal intensity well demarcated from adjacent fat tissue. The lesions were poorly seen on T2-weighted images, where they appeared isointense or slightly hypointense to fat tissue in all cases. Prominent regions of increased signal intensity, presumably representing fluid in intermetatarsal bursae, were seen proximal to 10 of the 15 masses found with MR imaging.

Foot↗
PubMed1991

MR imaging of the lateral collateral ligament of the ankle.

The ankle is stabilized by three sets of ligaments: the medial collateral (deltoid) ligament, the syndesmotic ligamentous complex, and the lateral collateral ligament. Of these three, the lateral collateral ligament is the one most often injured in ankle sprains. Assessment of the extent of injury has classically relied on clinical evaluation; plain film radiographs (including stress views); and, in some acute situations, ankle arthrography and/or peroneal tenography. In this report we illustrate the use of MR in the evaluation of the lateral collateral ligament. The normal anatomy, pitfalls in image interpretation, and findings in cases of ligamentous injury are demonstrated.

Ankle Joint↗
PubMed1991

Bone remodelling after growth factor and cyclosporine A therapy for aplastic anemia.

We describe a patient with viral induced aplastic anemia who developed severe bone pain after treatment with multiple courses of antithymocyte globulin, cyclosporine A, recombinant human granulocyte macrophage colony stimulating factor and deferoxamine. Radiographs and bone biopsy revealed extensive new trabecular bone formation in long bone diaphyses and adjacent periosteal reaction. The effects of hematopoietic growth factors, cyclosporine A and deferoxamine on bone metabolism are reviewed.

Adolescent↗
PubMed1990

Milwaukee shoulder syndrome. Fifteen additional cases and a description of contributing factors.

Fifteen additional patients with Milwaukee shoulder syndrome are described, bringing our total series to 30 cases. The condition occurred predominantly in elderly women and was characterized by severe glenohumeral joint degeneration and dissolution of the fibrous rotator cuff. Synovial fluids contained few leukocytes, but were often blood tinged. Basic calcium phosphate crystal aggregates and particulate collagens were noted in nearly all fluids, and collagenase activity was detectable in some, but not all, fluids. The knee joints were involved with a similar process in about half of our patients. In contrast to primary osteoarthritis, lateral tibiofemoral compartment involvement was common. Factors that may predispose to this syndrome included deposition of calcium pyrophosphate dihydrate crystals, direct trauma or chronic joint overuse, chronic renal failure, and denervation.

Aged↗
PubMed1990

Lumbar facet joint capsule: appearance at MR imaging and CT.

The joint spaces and synovium of the lumbar facet joints extend beyond the articular surfaces of the joint in the majority of adults. The authors correlated magnetic resonance (MR) imaging, computed tomographic (CT), and axial cryomicrotome sections of 66 facet joints in nine cadavers. Extensions of the synovium and joint space along the superior and inferior articular processes, under the ligamentum flavum, and into the ligamentum flavum could be recognized with use of MR and, less successfully, CT. The injection of a paramagnetic contrast medium into the facet joint facilitated visualization of the capsule on MR images. On the ventral aspect of the lumbar facet joint, MR images showed regions of high signal intensity where the joint space extended into the ligamentum flavum or between the ligamentum flavum and lamina. On the dorsal aspect of the joint, MR demonstrated prominence of the fibrous joint capsule where the joint space extended under it along the inferior articular process or along the superior articular process. The variable appearance of the ventral and dorsal aspects of the lumbar facet joint on CT and MR images is due to extension of the synovium and joint space.

Adult↗
PubMed1990

MR imaging of the tarsal tunnel and related spaces: normal and abnormal findings with anatomic correlation.

The tarsal tunnel syndrome may be caused by extrinsic or intrinsic pressure on the posterior tibial nerve or its terminal branches. The specific symptoms depend on the extent of nerve involvement, and compression distal or proximal to the tarsal tunnel may result in variants of the syndrome. To define better the capability of MR imaging for evaluating this entity, we performed MR imaging on three normal subjects and correlated the images with cryomicrotome sections. Six patients with symptoms suggestive of tarsal tunnel syndrome also were studied with MR. In all normal subjects, MR images showed the flexor retinaculum and the structures passing deep to the retinaculum: the tibialis posterior tendon, flexor digitorum longus tendon, flexor hallucis longus tendon, and the posterior tibial neurovascular bundle. The medial calcaneal sensory branch(es) and the medial and lateral plantar nerves also were delineated. Mechanical causes of compression were shown in all six symptomatic patients. The pathologic entities included two neurilemomas, tenosynovitis involving all three tendons, a ganglion cyst arising from the flexor hallucis longus tendon sheath, posttraumatic fibrosis, and post-traumatic fibrosis with associated posttraumatic neuroma. The MR findings were confirmed surgically in five cases. MR imaging can accurately depict the contents of the tarsal tunnel and the courses of the terminal branches of the posterior tibial nerve. In our small series, MR imaging accurately showed the lesions responsible for tarsal tunnel syndrome.

Ankle↗
PubMed1987

Painful pseudarthrosis following lumbar spinal fusion: detection by combined SPECT and planar bone scintigraphy.

Twenty-six adult patients more than 6-months post-lumbar spinal fusion were studied. Flexion and extension radiographs showing motion or bone scintigrams showing focal areas of increased activity within the fusion mass were considered positive for pseudarthrosis. Patients were classified as either symptomatic or asymptomatic. Among the 15 symptomatic patients, scintigraphy had a sensitivity of 0.78 and a specificity of 0.83 which was superior to the 0.43 sensitivity and 0.50 specificity of radiography. Six of the 11 asymptomatic patients had focal areas of increased activity in the bony fusion mass, possibly reflecting painless pseudarthrosis. Planar imaging was substantially enhanced by SPECT in 14 of the 26 cases. It is concluded that for the patient who remains symptomatic after lumbar spinal fusion, bone scintigraphy with SPECT is of significant value in detecting painful pseudarthrosis.

Adult↗
PubMed1987

High resolution surface coil magnetic resonance imaging of the joints: anatomic correlation.

Magnetic resonance imaging appears to be a particularly promising approach to the evaluation of articular and periarticular abnormalities. Its ability to produce images in multiple planes directly (without reconstruction) provides a unique advantage over CT for the radiologist when he attempts to interpret the complex three dimensional anatomy of most joints. The inherent contrast resolution of MR is excellent, and with the use of surface coils, spatial resolution is sufficient to permit the identification of the small soft tissue structures in and around joints. Artifacts generated by respiratory and cardiac motion are not a problem in MRI of the joints as they are in MR scanning of the body. Based on all these qualities, we believe that MRI will play an important role in the diagnosis of joint abnormalities.

Ankle Joint↗
PubMed1987

Failed temporomandibular joint prostheses: MR imaging.

Magnetic resonance (MR) imaging with surface coils was performed on 43 temporomandibular joints with disk prostheses in 28 patients who had pain, dysfunction, or both after implantation of the prostheses. Fracture was diagnosed prospectively as a discontinuity of the prosthesis on the MR examination; the sensitivity and specificity of MR imaging for this diagnosis was determined on the basis of these studies. All patients underwent surgery, after which the final diagnosis was made. MR imaging was found to have a sensitivity of 0.81 and a specificity of 0.91. Other MR findings included an abnormal amount of soft tissue surrounding the disk, thinning of the disk, osteophytes, and erosion of the condyle. An as yet unexplained artifact was frequently seen and obscured the prostheses in four of the six false-negative studies. The one false-positive case resulted from the interpretation of a markedly thinned but intact region of the prosthesis as a fracture.

Female↗
PubMed1987

High-resolution MR imaging of the normal rotator cuff.

The shoulders of six normal volunteers were imaged with high-resolution MR in the axial, sagittal, and coronal planes. An angled pair of counter-rotating current loop-gap resonators designed specifically for the shoulder was used as a local coil. All images were compared with corresponding cryomicrotome sections from cadaver shoulders. The rotator cuff was analyzed in detail. It appeared as a complex, heterogeneous band to tissue superficial to the humeral head. The areas of low signal intensity corresponded to the central tendons of the four rotator cuff muscles. These tendons could be distinguished from each other as well as from the intervening components of the cuff, which have a moderate intensity. We concluded that MR is capable of imaging the normal rotator cuff and of separating the various components. This may allow for improved precision in the diagnosis of rotator cuff disorders.

Adult↗
PubMed1987

MR imaging of the shoulder: diagnosis of rotator cuff tears.

Twenty-five patients with known or suspected tears of the rotator cuff in 26 shoulders underwent MR imaging. All patients also underwent arthrography or surgery. MR visualized abnormalities consistent with a tear in 20 of the 22 tears diagnosed by arthrography or surgery. In most cases, tears were seen as regions of increased signal intensity within the cuff on long-TR pulse sequences, although two cases simply showed an almost complete absence of normal cuff. The MR appearance of the two cases with partial tears was similar to that of full-thickness tears. Of the four cases with normal arthrograms, one case had MR findings consistent with a tear. We conclude that MR has good potential for the noninvasive diagnosis of rotator cuff tears. Its ultimate role in this diagnosis must await prospective studies comparing its accuracy with that of sonography, CT, and arthrography.

Adult↗
PubMed1987

Comparison of high-resolution MRI and SPECT bone scintigraphy for noninvasive imaging of the temporomandibular joint.

Prospective evaluation by magnetic resonance imaging (MRI) and both single photon emission computed tomography (SPECT) and planar bone scintigraphy was undertaken in 31 temporomandibular joints (TMJs) of 21 symptomatic patients. When compared with the results of subsequent arthrography, MRI (0.88) was more sensitive than SPECT (0.76) or planar (0.56) scintigraphy for detection of internal derangement of the TMJ. A diagnostic sensitivity of 0.96 was achieved when the results of either MRI or SPECT was considered evidence of internal joint derangement. Five symptomatic TMJs, clinically thought to be abnormal, were positive on SPECT but showed no evidence of anterior disk displacement at the time of arthrography. In such instances, SPECT may be detecting functionally significant altered joint mechanics that are not evident on anatomic imaging of the TMJ.

Adolescent↗