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Biomedical subjects

D L Janzen

Publications and source records attributed to D L Janzen.

At least 37 records · Page 2Linked to original sources
PubMed1997

Nuchal fibrocartilaginous pseudotumor: a distinctive soft-tissue lesion associated with prior neck injury.

Soft-tissue tumors with a predilection to involve the head and neck region include spindle cell lipoma, pleomorphic lipoma, and nuchal fibroma. We have recently studied three patients with distinctive soft-tissue fibrocartilaginous masses in the posterior aspect of the base of the neck, at the junction of the nuchal ligament and the deep cervical fascia. Two of the patients were women (ages 37 and 40) and one a man (age 53). All three had sustained neck injuries in automobile accidents in the past (27 years, 20 years, and 2 months before surgery, respectively). Each patient presented with a soft-tissue nodule overlying the spinous process of one of the lower cervical vertebrae. Two were painful. Computed tomography and magnetic resonance imaging performed in two patients showed focal thickening of the ligamentum nuchae at the C4-5 and C5-6 levels. All three masses were completely excised. They ranged in size from 1.0 to 1.5 cm. The three lesions were histologically identical, and each consisted of a poorly defined, moderately cellular fibrocartilage nodule located within the nuchal ligament at its junction with the deep cervical fascia. Atypia or mitotic activity was not present. The ligamentous tissue adjacent to the mass was irregular and degenerated. None of the masses have recurred in follow-up periods of 3 to 6 months, and all patients are currently asymptomatic. The lesion we describe is a distinctive soft-tissue pseudotumor that occurs in the mid-line of the lower cervical spine within the nuchal ligament. It is likely non-neoplastic and probably develops as a reaction to soft-tissue injury, in an analogous manner to fibrocartilage metaplasia seen in degenerated tendoligamentous structures. We propose the term "nuchal fibrocartilaginous pseudotumor" for these lesions.

Adult↗
PubMed1997

Osteonecrosis after contact neodymium:yttrium aluminum garnet arthroscopic laser meniscectomy.

OBJECTIVE: The purpose of this report is to describe two cases of osteonecrosis that occurred after arthroscopic meniscectomy with a contact neodymium:yttrium aluminum garnet laser system. The patients developed increasing knee pain and disability 5 months and 6 months after laser meniscectomy. MR imaging showed subchondral osteonecrosis in the femoral condyle and tibial plateau immediately adjacent to the site of laser meniscectomy in both patients. One patient required a total knee replacement to alleviate knee symptoms, and the other patient required a tibial osteotomy and surgical elevation of collapsed tibial articular surface. CONCLUSION: To our knowledge, this complication of laser arthroscopic meniscectomy has not been reported in the radiology literature. The clinical and MR imaging features of this important complication are described and possible causative mechanisms are discussed.

Adult↗
PubMed1996

Chondroid lipoma: MRI appearances with clinical and histologic correlation.

Chondroid lipoma is a recently described benign tumor of adipose origin which, pathologically, mimics myxoid liposarcoma and myxoid chondrosarcoma. This tumor typically presents as a well-defined mass in the superficial tissues of the extremities. In this report, we present the magnetic resonance imaging (MRI) appearances of a pathologically proven chondroid lipoma. To our knowledge, this is the first report of any imaging findings associated with this tumor.

Adipose Tissue↗
PubMed1996

Post-radiation osteosarcoma of the scapula.

Osteosarcomas arising in irradiated tissues are uncommon but important complications of radiotherapy. Radiation-induced osteosarcomas generally occur 3-30 years after exposure and are most common after radiotherapy for cervical or breast carcinoma. These tumors are usually rapidly growing, extremely painful, and histologically high grade. In this paper, we report two cases of high-grade post-radiation osteosarcoma of the scapula. Despite being almost identical radiologically and pathologically, one case had a typical clinical presentation whereas the second case had two unusual features, being non-painful and arising in a field initially irradiated for bronchogenic carcinoma.

Aged↗
PubMed1996

Diaphyseal telangiectatic osteosarcoma as a second tumor after bilateral retinoblastomas.

In this report, we describe the clinical, imaging, and pathologic findings in a case of diaphyseal telangiectatic osteosarcoma arising 23 years after successful treatment of bilateral retinoblastomas. To our knowledge, telangiectatic osteosarcoma occurring as a second tumor in this setting, outside the radiation treatment field, has not been previously reported. The association of the RB-1 gene defect with retinoblastomas and other tumors is discussed. Also, the computed tomography and magnetic resonance imaging findings in telangiectatic osteosarcoma are described and discussed.

Adult↗
PubMed1996

Improving the detection of radiographically occult ankle fractures: positive predictive value of an ankle joint effusion.

OBJECTIVE: To assess the value of an ankle effusion on plain radiographs as a predictor of radiographically occult fracture after acute ankle trauma. PATIENTS: Consecutive patients with acute ankle trauma and radiographic evidence of an ankle joint effusion. Patients were excluded if ankle trauma was sustained more than 48 h previously or if a fracture was visible on initial photographs. METHODS: All subjects (n = 26) underwent computed tomography (CT) of the ankle in sagittal and coronal planes. Ankle effusion size was measured from initial lateral ankle radiographs. RESULTS: Twelve patients (46%) had radiographically occult fractures identified with CT. Fracture sites included: posterior or lateral malleoli (n = 4), calcaneus (n = 1), or talus (n = 7). Ankle effusion size was 11.2 mm in the group without fracture and 17.1 mm in the group with fracture (P < 0.0001). The positive predictive value of an effusion 15 mm or greater was 83%. CT detected significant soft-tissue injuries in four (15%) patients including peroneal retinaculum tear (n = 1), anterior talofibular ligament avulsion (n = 1), and tears of the peroneus longus (n = 1) and tibialis posterior (n = 1) tendons. CONCLUSIONS: The presence of a large ankle effusion of radiographs after acute ankle trauma suggests an underlying fracture. An ankle effusion of > or = 15 mm is a reasonable threshold to prompt additional imaging. Computed tomography provides good visualization of subtle bone injuries and may detect clinically imported soft-tissue injuries.

Adult↗
PubMed1996

Using tomography to diagnose occult ankle fractures.

STUDY OBJECTIVES: To determine the incidence of occult ankle fractures and to determine whether an ankle effusion identified radiographically correlated with the presence of an occult fracture. METHODS: Attending physicians in the emergency department of a university hospital prospectively identified patients with acute ankle injuries that produced ecchymosis or edema over two or more major ligaments of the ankle. Plain radiographs of these patients demonstrated ankle effusions without fractures. A consecutive sample of patients with acute ankle injuries was selected. Thirty-six of 1,151 patients were eligible to enter the study; 2 of these patients subsequently were excluded from the data analysis. All eligible patients underwent plain ankle tomography at 3-mm intervals in the coronal and sagittal planes. The types and frequencies of occult ankle fractures identified on plain film tomography were noted. The distention of the ankle joint capsule of enrolled patients was measured to determine if the degree of effusion correlated with the presence of an occult fracture. RESULTS: The minimum incidence of occult fractures in the general population with ankle injuries was 1%. Twelve of 34 patients (35%) with acute, severe injuries had occult fractures. Depending on the size, an effusion was correlated with the presence of an occult fracture in 35% to 85% of the study population. CONCLUSION: Plain film tomography should be used when evaluating ankle injuries if both edema or ecchymosis over two or more stabilizing ligaments and radiographic evidence of an effusion are present simultaneously.

Acute Disease↗
PubMed1996

Image-guided percutaneous biopsy of musculoskeletal tumors: an algorithm for selection of specific biopsy techniques.

OBJECTIVE: The purpose of this study was to design and use an algorithm for selection of the most appropriate biopsy technique. MATERIALS AND METHODS: An algorithm was designed to maximize the tissue sampling and diagnostic accuracy of musculoskeletal tumor biopsy. We used fine-needle aspiration to sample small ( < 3 cm) soft-tissue masses, an 18-gauge automated Biopty Gun to sample large ( > 3 cm) soft-tissue masses, a bone-cutting core biopsy needle to sample sclerotic bone tumors, and a combination technique to sample lytic bone tumors with an intact bony shell. We reviewed the results of 46 consecutive biopsies obtained with this algorithm. RESULTS: The overall diagnostic accuracy was 96%, with one inadequate biopsy and one inaccurate biopsy. The diagnostic accuracies within subgroups of tumor types were: primary malignant tumors (n = 15), 93%; primary benign tumors (n = 9), 100%; secondary malignant tumors (n = 11), 100%; secondary benign tumors (n = 8), 88%; and infections (n = 3), 100%. CONCLUSION: This algorithm allows selection of the biopsy procedure most likely to safely provide adequate and accurate biopsy samples.

Adolescent↗
PubMed1996

Painful os cuboideum secundarium. Cross-sectional imaging findings.

The authors presented the computed tomography and magnetic resonance imaging appearances of a painful os cuboideum secundarium. To the authors' knowledge, this is the first report of the cross-sectional imaging appearance of this condition, and serves to underline the utility of computed tomography and magnetic resonance imaging in the investigation of foot pain.

Adult↗
PubMed1996

Magnetic resonance imaging and histopathologic appearances of benign soft-tissue masses of the foot.

Magnetic resonance imaging (MRI) is now the modality of choice for the investigation of soft-tissue tumours, providing excellent anatomic detail and soft-tissue contrast. As the availability of MRI has increased, the number of requests for studies of the foot and ankle has similarly increased. The imaging department at the authors' institution, a tertiary care teaching hospital, has a large orthopedic and podiatric referral base, and as a consequence the authors have had the opportunity to study a large variety of benign soft-tissue tumours with MRI. In this pictorial essay they review the MRI and pathological appearances of the most common benign soft-tissue tumours that occur in the foot and ankle.

Adult↗
PubMed1996

The snapping hip: clinical and imaging findings in transient subluxation of the iliopsoas tendon.

OBJECTIVE: To define the clinical, ultrasonographic and magnetic resonance imaging (MRI) findings in patients with painful snapping of the hip secondary to transient subluxation of the iliopsoas tendon. PATIENTS AND METHODS: Seven patients, ranging in age from 17 to 30 years, with a total of eight painful snapping hips were examined with static and dynamic ultrasonography and MRI during hip motion producing the painful snapping. The duration of symptoms, the level of disability and the response to therapy were recorded. RESULTS: Static ultrasonography showed thickening of the iliopsoas tendon (tendinitis) in two cases and a peritendinous fluid collection in two cases. In all cases dynamic ultrasonography of the iliopsoas tendon during hip motion showed distinct abnormal motion of the tendon corresponding temporally to the painful palpable and audible sensation. MRI showed normal intra-articular structures in all cases, tendinitis in two cases and iliopsoas bursitis in one case. Clinically, subluxation of the iliopsoas tendon is a chronic (mean duration of symptoms in this series, 23 months) disabling condition that may be relieved by surgical tendon release. CONCLUSIONS: Dynamic ultrasonography is useful for detecting transient subluxation of the iliopsoas tendon in patients with a painful snapping hip. MRI is useful for excluding intra-articular abnormalities in patients with this condition.

Adolescent↗
PubMed1996

Tear of the distal biceps tendon presenting as an antecubital mass: magnetic resonance imaging appearances.

OBJECTIVE: To present the magnetic resonance imaging (MRI) findings for tear of the distal biceps tendon presenting as a soft-tissue mass in the antecubital fossa. PATIENTS AND METHODS: The authors identified four patients who had been referred for MRI of an antecubital soft-tissue mass and in whom a tear of the distal biceps tendon was found. RESULTS: All four patients had typical MRI findings for a tear of the distal biceps tendon. In three, a tear at the insertion of the tendon onto the radial tuberosity was associated with small fluid collections at the site of the tear. In one patient there was thinning of the tendon and fluid within the tendon sheath. The diagnosis was confirmed by clinical correlation and follow-up of at least 1 year (in two patients) or by surgical exploration (in two). CONCLUSIONS: With knowledge of the MRI appearance of distal biceps tendon tear, it should be possible to correctly diagnose the problem, even when the clinical presentation does not suggest the diagnosis.

Adult↗
PubMed1996

Extrinsic radiocarpal ligaments: magnetic resonance imaging of normal wrists and scapholunate dissociation.

OBJECTIVE: To determine whether magnetic resonance imaging [MRI] in planes of imaging parallel to the known course of the extrinsic radiocarpal ligaments of the wrist aids in the visualization of these structures. SUBJECTS AND METHODS: MRI was performed on 32 wrists: a single normal cadaveric wrist, 23 normal wrists in volunteers and 8 wrists in patients with known scapholunate dissociation and rotatory scaphoid subluxation. Proton-density and T2-weighted images were obtained in the sagittal plane and gradient recalled echo images in an oblique sagittal plane, selected to parallel the extrinsic radiocarpal ligaments. The images were interpreted by two musculoskeletal radiologists. Each of the six main extrinsic ligaments was assessed for visualization or nonvisualization, and the morphologic features of those visualized were documented. RESULTS: With the exception of the dorsal radioscaphoid ligament, the volar and dorsal extrinsic radiocarpal ligaments were all consistently visualized in the normal wrists. For the eight cases of scapholunate dissociation, MRI demonstrated underlying rupture or thickening of the volar radioscaphocapitate ligament in all wrists and of the dorsal radiolunate ligament in five. CONCLUSION: MRI in the true and oblique sagittal planes can consistently demonstrate the extrinsic radiocarpal ligaments of the wrist. With this technique, extrinsic ligamentous abnormality can be demonstrated in patients with scapholunate dissociation and rotatory scaphoid subluxation.

Adult↗