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Biomedical subjects

C A Helms

Publications and source records attributed to C A Helms.

At least 73 records · Page 4Linked to original sources
PubMed1990

Pseudopermeative skeletal lesions.

Permeative bone lesions are well known to radiologists and usually invoke a differential diagnosis that includes aggressive lesions such as round cell malignancies and infection. In contrast to permeative lesions, which demonstrate multiple small holes at the endosteal surface of the cortex secondary to a medullary process, we describe a series of 19 patients (seven with aggressive osteoporosis, eight with prior radiation therapy and four with hemangiomas) who demonstrated multiple tiny lucencies in the cortex which were superimposed on the medullary space and mimicked a permeative pattern radiographically. We termed this a pseudopermeative pattern. Recognition of a pseudopermeative pattern may allow a less sinister differential diagnosis to be considered and may avert unnecessary biopsy in many instances.

Adult↗
PubMed1990

Magnetic resonance imaging of the postoperative lumbar spine.

Magnetic resonance (MR) imaging is a powerful diagnostic tool for patients with the failed back surgery syndrome. The multiplanar imaging capability, superior soft-tissue contrast resolution, and excellent tissue characterization are its major advantages. It displays the changes caused by surgical intervention as well as associated postoperative findings, many of which cause the failed back surgery syndrome. Most recently, gadolinium-DTPA-enhanced MR imaging of the spine, combined with noncontrast MR imaging, has shown heretofore unparallelled sensitivity and accuracy.

Humans↗
PubMed1989

Magnetic resonance imaging of the knee: current status, new directions.

A number of techniques for magnetic resonance imaging of the knee are reviewed. Spin-echo imaging sequences are at present the most widely used and are capable of demonstrating a wide range of pathology including cruciate and collateral ligament tears, meniscal abnormalities, and synovial disease. Fast scan imaging provides effective T2-weighting without the time penalty of T2-weighted spin-echo imaging. These fast scan techniques have also permitted the development of novel sequences including radial techniques and three-dimensional Fourier transform/volume acquisition (which may potentially become the imaging technique of choice in the knee). Inversion recovery may play an important role in evaluating cartilage disorders in the future. The strengths of each technique are discussed together with possible clinical applications.

Humans↗
PubMed1989

Automated percutaneous lumbar discectomy.

Lumbar spine disc disease has traditionally been treated surgically by laminectomy and manual removal of the offending disc material. Chymopapain was extensively used to decompress the disc pressure in a relatively noninvasive manner, but has been abandoned due to serious complications, including anaphylaxis and paraplegia. Onik introduced automated percutaneous discectomy in 1985. This procedure has proved safe and efficacious for treating lumbar disc disease without complications. It is performed on an out-patient basis under local anesthesia with minimal rehabilitation time. The success rate reported in a multiinstitutional study with one year follow-up is approximately 75%. The majority of failures occur in patients with free fragments or spinal stenosis - both of which can be diagnosed preoperatively with good imaging examinations. Hence, the success rate can be expected to improve if preoperative imaging is relied upon to help choose appropriate patients. Over 30,000 percutaneous discectomy procedures have been performed. The only complication reported, disc infection, developed in fewer than 0.2% of cases. Automated percutaneous discectomy has the potential to treat a vast number of patients with lumbar disc disease who otherwise would have laminectomies.

Fluoroscopy↗
PubMed1989

MRI of the knee in diffuse pigmented villonodular synovitis.

Magnetic resonance imaging (MRI) was performed on 11 patients with surgically proven pigmented villonodular synovitis (PVNS) of the knee. PVNS was diagnosed on the basis of presence of hemosiderin, joint effusion, and hyperplastic synovium without significant joint destruction. MRI provided a detailed map of the distribution of the disease within the joint, emphasizing the common occurrence of the disease behind the cruciate ligaments and in synovial cysts in the popliteal fossa. MRI aided in preoperative planning and postoperative follow-up for residual and recurrent disease. Nine additional cases of joint hemorrhage, hemophilia, desmoplastic tumors, and synovial chondromatosis were included to delineate differential diagnostic criteria.

Adult↗
PubMed1989

Coronoid process hyperplasia: CT studies.

Coronoid process hyperplasia is a disorder that causes restricted jaw movement due to enlargement of the coronoid process of the mandible, which impinges on the zygomatic arch with mouth opening. The cause is unclear. Computed tomographic (CT) findings in three patients with this disorder (two bilateral, one unilateral)--including a 3-year-old boy who may be the youngest patient with this disorder ever reported--include an enlarged coronoid process, with sclerosis and erosion of the zygomatic arch. CT is an effective and rapid method for establishing the diagnosis.

Adult↗
PubMed1989

Retrorenal colon: implications for percutaneous diskectomy.

It has been recommended that computed tomography (CT) with the patient prone be performed in every patient undergoing percutaneous diskectomy; this would enable detection of a retrorenal location of the colon, which could interfere with the percutaneous procedure. In this evaluation of 346 prone CT studies, only one patient (0.29%) was found to have retrorenal or retropsoas bowel that would have been perforated at diskectomy. Because of this extremely low prevalence, the performance of prone CT in every patient undergoing percutaneous lumbar diskectomy is not believed to be necessary.

Adolescent↗
PubMed1989

Temporomandibular joint: morphology and signal intensity characteristics of the disk at MR imaging.

Magnetic resonance (MR) imaging has been used in the temporomandibular joint (TMJ) primarily to define the disk position. This report examines altered morphology and signal intensity characteristics of the TMJ disk as they relate to the severity of internal derangement. Two hundred sixteen joints in 133 patients with a history of such derangement. were imaged with MR. Disk position, signal intensity, morphology, and the presence of osteoarthritis were determined for each joint. The normal disk was not anteriorly displaced and had a normal "bow-tie" shape. A grade 1 disk was anteriorly displaced and had a normal shape; a grade 2 disk was anteriorly displaced and had an abnormal shape. Forty (19%) joints were considered normal; none of these exhibited osteoarthritis. One hundred thirty-nine (64%) joints were grade 1; osteoarthritis was found in 17%. Thirty-seven (17%) were grade 2; osteoarthritis was found in 95%. All forty normal joints had high or intermediate signal intensity in the disk. Osteoarthritic joints had a higher percentage of disks with diminished intensity (P less than .0001). Severe or untreated osteoarthritis is known to be a complication of TMJ internal derangements; hence this grading system seems to correlate with the severity of internal derangement.

Adult↗
PubMed1989

Hypertrophy of C-1 anterior arch: useful sign to distinguish os odontoideum from acute dens fracture.

Dens fractures are often difficult to detect radiographically because of overlapping structures. The lateral radiographs were examined of all patients at the authors' institution who demonstrated an abnormal odontoid process or an abnormal anterior arch of C-1. Six patients were found: Four had os odontoideum, one had rheumatoid arthritis, and one had a congenital defect in the posterior arch of C-1. All had hypertrophy of the C-1 anterior arch on the lateral view. The width of the anterior arch of C-1 and the cortical thickness of the anterior arch in these six patients were measured and compared with the findings in a control group of 20 patients; the measurements from the six patients were found to be significantly greater. Hypertrophy of the anterior arch of C-1 is a useful sign of a chronic pathologic condition at the atlantoaxial articulation, and in the setting of acute trauma it may be an important clue that prevents unnecessary invasive treatment for a mistaken diagnosis of fractured dens.

Acute Disease↗
PubMed1989

Glenoid labrum: preliminary work with use of radial-sequence MR imaging.

The authors describe a magnetic resonance imaging method for examination of the glenoid labrum of the shoulder joint that utilizes a radial fast-imaging sequence. Seven shoulders were examined: a total of five in three healthy asymptomatic volunteers, one in a symptomatic patient not suspected of having a lesion of the glenoid labrum, and one in a patient with recurrent shoulder dislocation and surgical proof of an extensive tear of the labrum. The preliminary results suggest that this technique may advantageously demonstrate pathologic changes in the glenoid labrum and may contribute to the evaluation of the unstable and painful shoulder.

Adult↗
PubMed1989

Immature bone infarcts: findings on plain radiographs and MR scans.

We studied the plain film findings in eight patients with immature bone-marrow infarction and correlated the findings with those of MR imaging in four of the cases. Seven patients had underlying systemic disease, including sickle cell disease (two), systemic lupus erythematosus (two), acute lymphocytic leukemia (one), non-Hodgkin lymphoma (one), and renal transplantation (one). In one patient, the bone infarct was idiopathic. Plain films in three of the eight cases were misinterpreted as showing aggressive lesions (i.e., malignancy or infection), and these patients underwent a biopsy that proved the diagnosis of bone infarction. In the other five cases, the diagnoses were established by clinical follow-up. The plain film findings in all eight cases consisted of subtle, mottled, ill-defined radiolucencies in the diametaphyseal region. Four of the patients had mild sclerosis. MR imaging in all four cases in which it was performed showed a central area with high or intermediate signal with a serpentine, thin, low-signal border. The lesions shown by MR imaging corresponded to the areas of abnormality on the plain films and had an appearance similar to that of previously reported bone infarcts. Our experience suggests that in patients with nonspecific subtle radiographic bone changes and an underlying systemic disease, MR imaging is helpful in establishing the diagnosis of bone marrow infarction.

Adolescent↗
PubMed1989

Staging of internal derangements of the TMJ with magnetic resonance imaging: preliminary observations.

Although MRI has been reported to be accurate in diagnosing displaced TMJ menisci, it has not been used to characterize the condition of the meniscus. A staging system of internal derangement of the TMJ using MRI signal characteristics and morphology of the meniscus is presented. A normal meniscus has the appearance of a small "drumstick" and is positioned superiorly on the mandibular condyle. It produces a small amount of intermediate signal on the MRI. A grade 1 displaced meniscus has normal shape and signal; a grade 2 meniscus has normal shape and absent signal; a grade 3 meniscus has abnormal shape and absent signal. There was a significant correlation between meniscus grade and chronicity of symptoms, severity of pain, and presence of degenerative joint disease in 62 joints (39 patients).

Adolescent↗
PubMed1989

Optimal mouth position for magnetic resonance imaging of the temporomandibular joint disk.

Optimal mouth positioning for magnetic resonance imaging of the TMJ is controversial. This study evaluates the closed mouth position and partial-open mouth position for diagnostic accuracy of anterior displacement of the disk. Sixty-two joints were considered abnormal in at least one position. In the positive joints, the closed mouth position sequences were all abnormal and diagnostic, while 34% of partial-open mouth position sequences were falsely normal. It was found that the closed mouth position provides higher diagnostic accuracy for disk displacement, although optimal examinations include imaging in both positions.

Adolescent↗
PubMed1989

CT and MR of lateral disc herniation: typical appearance and pitfalls of interpretation.

Lateral disc herniation is a relatively uncommon manifestation of intervertebral disc disease, defined as herniation of disc material lateral to or into the vertebral foramen. Failure to recognize this lesion preoperatively may lead to unsuccessful surgical exploration. We describe here the radiologic findings in seven patients with lateral disc herniation. Three were evaluated with magnetic resonance imaging alone, three with computed tomography alone, and one with both modalities. Example of three entities which may mimic lateral disc herniation (pseudodisc protrusion of scoliosis, paravertebral masses, and volume averaging artifacts) are illustrated.

Adult↗
PubMed1989

Temporomandibular joint synovial osteochondromatosis: CT manifestations.

Synovial osteochondromatosis is a rare arthropathy of the temporomandibular joint. We report the computed tomographic findings in two subjects with this disorder. Both patients had increased soft-tissue density in the joint with multiple small calcified densities, many of which displayed peripheral calcification. Extensive erosions of the surrounding bony structures were present, affecting the condylar process and fossa, and, in one instance, the walls of the external auditory and carotid canals were thinned. We believe that computed tomography is superior to conventional imaging techniques and is useful in the depiction of disease and surgical planning in patients with temporomandibular joint synovial osteochondromatosis.

Adult↗