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Biomedical subjects

L L Seeger

Publications and source records attributed to L L Seeger.

At least 73 records · Page 4Linked to original sources
PubMed1992

MRI of the musculoskeletal system.

MRI is rapidly altering the presurgical evaluation for many forms of musculoskeletal pathology, and the indications for MRI will undoubtedly continue to grow. Because of the complexity of this modality and the ability to totally "miss" pathology by the inappropriate choice of imaging plane or pulse sequence, cooperation between the orthopedic surgeon and the radiologist is essential. A close working relationship is required for maximum diagnostic information to be obtained with each examination and for optimal patient care.

Hip Joint↗
PubMed1992

Primary osteosarcoma of the thyroid gland.

Primary extraosseous osteosarcoma of the thyroid gland is a rare tumor which is associated with a poor prognosis. In this report, we discuss such a tumor and its recurrence in a 78-yr-old female with multinodular goiter, focusing on the imaging evaluation of this unusual tumor.

Aged↗
PubMed1991

Anatomy of the hip: correlation of coronal and sagittal cadaver cryomicrosections with magnetic resonance images.

Magnetic resonance imaging (MRI) is noninvasive and provides images with higher soft tissue contrast than possible with any other imaging modality. Unlike CT which depicts anatomy in the axial plane, MRI is capable of producing images in thin cross sections acquired directly in any plane, usually axial, coronal or sagittal planes. The use of diagnostic MR images is facilitated by an understanding of the detailed anatomy that is depicted. The purpose of this study was to identify anatomical structures in coronal and sagittal cryomicrosections of the hip region. Thin cryosections of the hips of fresh-frozen cadavers were obtained by a method developed by one of the authors (WR). These sections were matched with thin-section, high resolution MR images of a normal volunteer. The complex anatomy of the hip and its surrounding muscles, tendons and ligaments was exquisitely depicted on both the cadaver microcryosections and the matched MRT images.

Cadaver↗
PubMed1991

Preoperative evaluation of osteosarcoma: value of gadopentetate dimeglumine-enhanced MR imaging.

Decisions regarding the surgical approach in osteosarcoma require accurate assessment of tumor extent. In order to determine whether enhancement with gadopentetate dimeglumine could add clinically significant information to that available with unenhanced MR imaging, 21 patients with osteosarcoma underwent preoperative MR imaging. T1- and T2-weighted spin-echo MR images obtained before and after administration of IV gadopentetate dimeglumine were evaluated to determine the conspicuity of marrow and soft-tissue extent of tumor, including tumor involvement of major neurovascular bundles and adjacent joints. MR results were correlated with tumor margins found at surgery. In some instances, use of gadopentetate dimeglumine obscured differentiation of tumor from normal marrow or tumor infiltration into perineurovascular fat, and tumor extension through pseudocapsule could not be differentiated from peritumoral edema after contrast administration. Contrast enhancement did assist in differentiation of intraarticular tumor from effusion; however, synovial invasion could be identified on unenhanced T1-weighted images by loss of synovial fat and cortical disruption. These results indicate that gadopentetate dimeglumine does not assist in defining tumor margins of osteosarcoma.

Adolescent↗
PubMed1991

Diagnostic imaging of osteosarcoma.

The diagnosis, treatment planning, and follow-up evaluation of osteosarcoma rely heavily on a variety of imaging techniques. Plain roentgenography, radionuclide bone scanning, computed tomography, and magnetic resonance imaging play important roles in defining local tumor extent, detecting metastatic disease, and monitoring for recurrent tumor. Invasive studies such as angiography are now rarely necessary. In the future, newer imaging modalities, including positron emission tomography, can be expected to become important tools for evaluation of these tumors.

Angiography↗
PubMed1991

Nonspecific findings on MR imaging. The importance of correlative studies and clinical information.

Although magnetic resonance (MR) imaging is highly sensitive for the detection of abnormalities of the musculoskeletal system, changes in marrow and soft-tissue signal intensity are often nonspecific, and benign conditions may be mistaken for malignancy. In an effort to identify the cause of this type of misdiagnosis in MR examinations, the MR scans were reviewed of 30 patients whose images manifested bone and/or soft-tissue changes that were initially believed to be consistent with malignancy but were later found to represent benign conditions. Of the 30 patients, MR abnormalities were attributable to trauma in 11, benign tumors and tumorlike conditions in ten, infection in seven, and prior radiotherapy in two. In 24 cases, correlative imaging studies (14 patients), appropriate clinical history (six patients), and/or physical and laboratory examinations (four patients) would have avoided these misdiagnoses.

Adult↗
PubMed1991

Osteochondritis dissecans of the patella. MRI evaluation and a case report.

Osteochondritis dissecans of the patella is a rare cause of anterior knee pain. An illustrative case in a 22-year-old man demonstrates the current imaging modalities and surgical treatment. Specifically, magnetic resonance imaging (MRI) and arthroscopic knee surgery are discussed along with a review of the literature. Unlike standard roentgenograms, MRI can be helpful in determining the viability of the osteochondritic fragment and the amount of remaining attachment to the surrounding cancellous bone. This finding can have important bearing on choice of treatment. When surgery is indicated, arthroscopic treatment with excision of the fragment and curettage offers distinct advantages over open arthrotomy. Lateral release or other realignment procedures may be done in combination with the primary procedure. Prognosis for full recovery of knee function and relief of patellar pain is guarded in patients who require surgery.

Adult↗
PubMed1991

Magnetic resonance imaging of the shoulder.

Magnetic resonance imaging is an effective means for evaluating the painful shoulder. It has been shown to display accurately pathology associated with impingement syndrome and is useful in the detection of tears of the glenoid labrum. The role of magnetic resonance imaging in evaluation of synovial pathology has not yet been defined. Additional work is needed in this area.

Humans↗
PubMed1991

Advances in imaging of rheumatoid arthritis.

Several new imaging modalities have been found useful in clinical evaluation of patients with rheumatoid arthritis (RA). Magnetic resonance (MR) imaging has proven to be an excellent noninvasive method to evaluate the spine, shoulder, hip, and knees; its use for the evaluation of smaller joints is still being investigated. In patients with RA, MR imaging has been used to evaluate cervical spine instability, rotator cuff tear, osteonecrosis, and osteomyelitis. Patients with RA may have advanced osteoporosis, predisposing to insufficiency fractures. This includes fractures associated with increased activity after hip or knee arthroplasty. Newer methods for measuring the degree of osteoporosis include single photon absorptiometry, dual photon absorptiometry, quantitative computed tomography (CT), and dual-energy projection radiography. It has not yet been determined which of these methods will be most widely used in the future, but quantitative CT and dual-energy projection radiography currently show the most promise. Ultrasonography provides an excellent noninvasive method for the diagnosis of popliteal cysts, and color Doppler sonography can differentiate cyst and popliteal aneurysm. As compared to radiography or conventional CT, high-resolution CT provides an improved method to detect the early changes of RA in the lung parenchyma.

Arthritis, Rheumatoid↗
PubMed1990

Subchondral cysts of the tibia secondary to osteoarthritis of the knee.

Subchondral cysts of the tibia secondary to osteoarthritis of the knee are not usually seen on radiographs. When present, they are typically small and present no diagnostic difficulty. Two cases of unusually large subchondral lesions of the medial tibial plateau are presented. The lesions were well defined and lay adjacent to the medial tibial cortex with their long axes in the sagittal plane. Both were associated with moderate medial compartment osteoarthritis. Additional information obtained from computed tomography indicated that these lesions were subchondral cysts secondary to osteoarthritis rather than tumors or other tumor-like conditions.

Aged↗
PubMed1990

Tumoral calcinosis-like lesion of the proximal linea aspera.

Tumoral calcinosis is presently a poorly defined disease. In its classic form, it consists of multiple large foci of benign mineralization in the soft tissue adjacent to bone near large joints. Patients are generally of African descent and are adolescents or young adults at presentation. Both metabolic and traumatic etiologies have been proposed. We report six adult Caucasian patients with lesions that pathologically resembled tumoral calcinosis. All lesions were small (less than 3 x 3 cm) and were located along the proximal linea aspera of the femur. All patients presented with pain. Because of the atypical patient population and the unusual size and location of the lesions, we refer to this process as a "tumoral calcinosis-like lesion." A typical radiographic appearance and location, together with appropriate clinical history, can strongly suggest this diagnosis.

Aged↗
PubMed1990

Magnetic resonance imaging of knee trauma.

This article reviews the magnetic resonance (MR) appearance of normal knee anatomy and the role of MRI in the evaluation of knee trauma. Images acquired in the sagittal plane are the most useful. A combination of T1- and T2-weighted spin echo pulse sequences is most commonly employed. A meniscal tear is identified by an intrameniscal signal which extends to the joint surface. MR and arthroscopic findings agree in more than 90% of patients. It is important to be familiar with the MRI appearance of normal anatomic variants that may be confused with meniscal tears: the transverse geniculate ligament, the hiatus of the popliteal tendon sheath, and the meniscofemoral ligaments. Tears in the anterior cruciate, posterior cruciate, and collateral ligaments are also depicted.

Humans↗
PubMed1990

Magnetic resonance imaging of pediatric musculoskeletal trauma.

MRI is an important tool for evaluating acute and chronic injuries to the musculoskeletal system. It is effective in demonstrating abnormalities in the knee and hips and in detecting bone and ligamentous trauma that is not evident radiographically.

Bone Marrow↗
PubMed1990

Posterior cruciate ligament: MR imaging.

The authors reviewed 610 consecutive magnetic resonance (MR) examinations of patients with suspected internal derangements of the knee, paying special attention to the posterior cruciate ligament (PCL). The normal PCL shows a low MR signal intensity and an arcuate shape. An accessory anterior or posterior meniscofemoral ligament was identified in 58.5% of examinations. Among 202 patients who underwent arthroscopy or arthrotomy, MR imaging depicted 11 PCL injuries: eight complete or incomplete ligament disruptions and three avulsions. All were confirmed by means of arthroscopy or arthrotomy. MR findings of PCL injury were anatomic disruption, increased signal intensity in the ligament, and redundancy of an avulsed ligament. Of the 11 PCL injuries, four were not detected at initial clinical examination. In none of the 202 patients in whom arthroscopy or surgery was performed was an abnormal PCL identified in the presence of a normal MR examination. MR imaging is a reliable method for the detection of PCL injuries.

Adolescent↗
PubMed1990

Widespread inflammatory response to osteoblastoma: the flare phenomenon.

A case of vertebral osteoblastoma caused a diffuse, reactive inflammatory infiltrate in two vertebrae, adjacent ribs, and the paraspinous soft tissues. The authors call this the flare phenomenon. On magnetic resonance images the diffuse inflammatory response caused a misleading appearance that simulated a malignant process (lymphoma or Ewing sarcoma). A computed tomographic myelogram was diagnostic.

Adult↗
PubMed1990

An integrated approach to the evaluation of metastatic bone disease.

The radionuclide bone scan is the most effective whole body screening test for bone metastases. Conventional radiography, although relatively insensitive to the presence of bone metastases, is the best modality for characterizing them once they are detected in radionuclide scans. When the radionuclide bone scan and appropriate correlative radiographs are analyzed and reported together, false-positive scan findings are reduced, and scan specificity is increased. Valuable information on response to treatment may be obtained by correlating the changes seen in radiographs and radionuclide bone scans. CT or MR imaging may be useful for evaluating suspicious radionuclide bone scan findings that cannot be explained radiographically, and may influence the decision regarding the need for biopsy. CT can also be used to monitor needle-biopsy procedures. The use of CT or MR imaging is helpful in determining the local extent of metastatic disease when planning palliative surgery or radiotherapy. Although a positive diagnosis by needle biopsy is considered definitive, a negative result must be suspect and may eventually necessitate open surgical biopsy. An algorithmic approach to the workup of a possible skeletal metastasis is illustrated in Figure 12.

Bone Neoplasms↗