PubMed Health⌕ Search

Biomedical subjects

L Lenchik

Publications and source records attributed to L Lenchik.

34 records · Page 2Linked to original sources
PubMed1997

Fibrolipomatous hamartoma: MR imaging findings.

OBJECTIVE: To analyze the MR imaging features of fibrolipomatous hamartoma (FLH) of nerves. DESIGN AND PATIENTS: MR imaging studies from six patients (three men and three women) were retrospectively reviewed by three musculoskeletal radiologists. In four patients, a biopsy of the nerve lesion was performed. In two patients, biopsy data were unavailable and the diagnosis was based on the clinical history combined with the MR imaging findings. RESULTS AND CONCLUSION: MR imaging demonstrated fusiform nerve enlargement that was caused by fatty proliferation and thickening of nerve bundles. Nerve bundles appeared as serpentine tubular structures, hypointense on both T1- and T2-weighted images. The degree of fatty proliferation varied among patients. In addition, significant variation in the distribution of fat along the course of the nerves was noted. In three patients, FLH followed the branching pattern of the nerves, a characteristic pathologic finding. In two patients, intramuscular fat deposition (biceps and tibialis posterior muscles) was present. MR imaging findings of FLH are typical, allowing a confident diagnosis. The variation of fatty proliferation among patients and involved nerves as well as the tendency of the abnormalities to follow the branching pattern of the nerves is well demonstrated with MR imaging. FLH may present as an isolated nerve lesion, may be associated with intramuscular fat deposition, or may occur as a feature of macrodystrophia lipomatosa (MDL).

Adult↗
PubMed1997

Normal patellar retinaculum: MR and sonographic imaging with cadaveric correlation.

OBJECTIVE: The purpose of our study was to define retinacular anatomy with MR imaging and sonography. MATERIALS AND METHODS: Five cadaveric knee specimens underwent sonography and MR imaging using the following sequences: T1-weighted axial, sagittal, coronal, and five oblique planes and axial three-dimensional gradient-echo imaging. Three knees were injected with gelatin gadolinium solution before imaging. All five specimens were sectioned. Correlation was made between findings derived from MR imaging, sonography, and cadaveric sections. RESULTS: T1-weighted axial images without intraarticular gadolinium were most useful for revealing the superficial layer and deep ligaments of the retinacula; however, the oblique sagittal and oblique coronal planes showed the deep ligaments more clearly in their craniocaudal dimensions. Sonography revealed the retinacula as bilaminar structures with discrete superficial and deep layers but failed to distinguish the deep ligaments from one another. CONCLUSION: Conventional T1-weighted axial MR images showed the various components of the retinacula including the medial patellofemoral ligament, which is an important stabilizing structure. Oblique imaging planes may be a helpful adjunct to axial imaging planes. Sonography can consistently identify the retinacula and may be useful in their assessment.

Aged↗
PubMed1996

Association of gastrocnemius tendon calcification with chondrocalcinosis of the knee.

OBJECTIVE: Chondrocalcinosis of the knee is a common radiological finding in the elderly. However, visualization of chondrocalcinosis may be difficult in patients with advanced cartilage loss. The purpose of this study was to determine sensitivity, specificity, and accuracy of gastrocnemius tendon calcification that might serve as a radiographic marker of chondrocalcinosis in patients with painful knees. DESIGN AND PATIENTS: We prospectively evaluated 37 knee radiographs in 30 consecutive patients (29 men, 8 women; mean age 67 years, age range 37-90 years) with painful knees who had radiographic evidence of chondrocalcinosis. The frequency of fibrocartilage, hyaline cartilage, and gastrocnemius tendon calcification was determined. For a control group, we evaluated knee radiographs in 65 consecutive patients with knee pain (54 men, 11 women; mean age 59 years, age range 40-93 years) who had no radiological signs of chondrocalcinosis. The frequency of gastrocnemius tendon calcification in the control group was determined. RESULTS: Gastrocnemius tendon calcification was 41% sensitive, 100% specific, and 78% accurate in predicting chondrocalcinosis. The gastrocnemius tendon was calcified on 15 of 37 (41%) radiographs in the experimental group and on 0 of 67 radiographs in the control group. In the chondrocalcinosis group, 23 (62%) had posterior hyaline cartilage calcification, 14 (38%) had anterior hyaline cartilage calcification, 31 (84%) had medial meniscus calcification, and 36 (97%) had lateral meniscus calcification. CONCLUSIONS: Our results show that gastrocnemius tendon calcification is an accurate radiographic marker of chondrocalcinosis in patients with knee pain.

Adult↗
PubMed1995

The value of MR in differentiating subligamentous from supraligamentous lumbar disk herniations.

PURPOSE: To determine the value of MR criteria in differentiating subligamentous from supraligamentous lumbar disk herniations. METHODS: A retrospective review of surgical reports and MR images of 50 patients undergoing first-time lumbar surgery was performed. Three MR imaging criteria were assessed: the presence and integrity of a low-signal-intensity line posterior to the disk herniation, the size of the disk herniation in comparison with the size of the spinal canal, and the presence of disk fragments. Correlation was made with surgical findings to determine the value of these MR criteria in differentiating subligamentous from supraligamentous disk herniations. RESULTS: For determining subligamentous disk herniations: the presence of a continuous low-signal-intensity line posterior to the disk herniation was 29% sensitive, 65% specific, and 42% accurate; disk herniation size less than 50% of the size of the spinal canal was 64% sensitive, 47% specific, and 58% accurate; and the absence of disk fragments was 88% sensitive, 12% specific, and 62% accurate. Combinations of individual MR criteria did not improve diagnostic accuracy. CONCLUSIONS: For differentiating subligamentous from supraligamentous lumbar disk herniations, none of the MR imaging criteria assessed was reliable.

Adolescent↗
PubMed1994

CT of the iliopsoas compartment: value in differentiating tumor, abscess, and hematoma.

OBJECTIVE: The iliopsoas compartment is an extraperitoneal space defined by the iliopsoas fascia; its major components include the iliacus, psoas major, and psoas minor muscles. Distinction of neoplastic, inflammatory, and hemorrhagic conditions of the iliopsoas compartment is often difficult, whether based on clinical evaluation or CT findings. The purpose of this study was to determine specific CT features that might help differentiate these three abnormalities. MATERIALS AND METHODS: We retrospectively reviewed CT scans of 44 patients who had abnormalities of the iliopsoas compartment (15 neoplasms, 21 abscesses, and eight hematomas). Final diagnoses were established by surgical biopsy (n = 14), percutaneous biopsy (n = 18), or clinical evidence (n = 12). Diagnoses were correlated with 11 CT features to determine findings that could be used to differentiate the three abnormalities. These included enlargement of the iliopsoas muscles; extent, margination, and attenuation of the lesion; presence of gas, calcification, bone destruction, fat infiltration, and fascial disruption; and associated fluid or adenopathy. The radiologist who interpreted the scans had no knowledge of the clinical findings. RESULTS: The most reliable CT features for each condition were as follows: irregular margins, 67% sensitive, 52% specific, and 57% accurate for neoplasms; low attenuation, 100% sensitive, 43% specific, and 70% accurate for abscesses; and diffuse involvement of the entire muscle, 88% sensitive, 78% specific, and 80% accurate for hematomas. Combinations of individual CT features did not improve the ability to differentiate the three conditions. CONCLUSION: Our results show that the efficacy of CT, when scans are interpreted without knowledge of the clinical history, is poor for differentiating iliopsoas neoplasms, abscesses, and hematomas.

Adolescent↗
PubMed1994

Computed tomographic evaluation of maximal diaphragmatic crural thickness.

The purpose of this study is to determine the range of maximal diaphragmatic crural thickness during different phases of respiration and to correlate crural thickness with age and gender. Prospective evaluation of computed tomographic (CT) scans of 200 patients without juxtacrural abnormalities was performed. Maximal short-axis crural thickness measurements were determined in all patients. Measurements were obtained at full inspiration during chest CT (n = 60), full expiration during abdominal CT (n = 89), and unknown phase of respiration during dynamic CT scans (n = 51). Maximal crural thickness measurements were analyzed by side, age, and gender. The right crus was thicker than the left crus in 91% of patients. The range of maximal crural thickness remained fairly constant from the second to the eighth decades of life. The range of maximal crural thickness was 1.8-18.8 mm in men and 1.8-21.1 mm in women. Maximal crural thickness does not significantly vary with age and gender for specific phase of respiration.

Adult↗
PubMedDate not supplied

MR imaging of rotator cuff tears: is there a diagnostic benefit of shoulder exercise prior to imaging.

The purpose of this study was to determine if shoulder exercise prior to MR imaging accentuates findings related to rotator cuff tears. In 32 consecutive patients undergoing MR imaging to evaluate the rotator cuff, after routine MR examination, the joint was moved by active or passive exercise (circumduction, including abduction, if possible) in an attempt to redistribute any joint fluid. The exercise was performed according to pain tolerance and for no longer than 4 minutes. The coronal oblique fast spin-echo T2-weighted images of these patients performed before exercise were reviewed by consensus agreement of two musculoskeletal radiologists who were blinded to clinical information. The appearance of the rotator cuff tendons and the distribution of fluid in the glenohumeral joint were determined. The identical postexercise MR images then were placed alongside the corresponding preexercise MR images, and a direct comparison of findings was made with regard to any change in the appearance of the rotator cuff or joint fluid by consensus opinion of the same two radiologists. Five patients (five shoulders) could not perform exercise because of pain. In the remaining 27 patients (27 shoulders), changes in the location of joint fluid were seen when the preexercise and postexercise images were reviewed together, the diagnosis of partial rotator cuff tear (n = 8) was changed to normal in two cases, and the diagnosis of partial tear was made with more confidence in one case. The diagnoses of normal rotator cuff (n = 16) and complete rotator cuff tear (n = 3) were unchanged. Eight patients had arthroscopy; in each of these, the preexercise and postexercise images showed similar results, and proved to be correct surgically (six normal, one partial rotator cuff tear, and one complete rotator cuff tear). Although postexercise MR images show changes in the distribution of joint fluid when compared to preexercise images, the diagnostic benefits of the postexercise images in the analysis of the rotator cuff appear to be limited.

Exercise↗
PubMedDate not supplied

Myositis ossificans of the foot.

A 37-year-old woman with myositis ossificans of the left foot is reported. A faint density was seen on foot radiographs, whereas computed tomography images showed a rim of mineralization inferior to the second and third metatarsal bones. On short tau inversion recovery-weighted magnetic resonance images, a hyperintense lesion was demonstrated with hyperintensity extending to the surrounding soft tissues. The rim of ossification appeared hypointense. Other non-neoplastic soft tissue processes with bone formation such as pseudomalignant osseous tumor of soft tissues, florid reactive periostitis, and bizarre parosteal osteochondromatous proliferation occur more commonly in the foot than myositis ossificans. A differential diagnosis of these lesions including periosteal and parosteal osteosarcoma, periosteal chondroma, and osteomyelitis is discussed.

Adult↗
PubMedDate not supplied

MRI of intracranial subependymomas.

OBJECTIVE: We report imaging features of two cases of subependymoma, a relatively rare benign intraventricular neoplasm. MATERIALS AND METHODS: The first case was a lateral ventricular tumor, which grew to a large size before becoming symptomatic. The second case was a fourth ventricular subependymoma with extensive cisternal spread. RESULTS: In Case 1, absence of postcontrast enhancement suggested the correct diagnosis. However, in Case 2 heterogeneous enhancement made the diagnosis uncertain. In both cases, pre- and postoperative MRI was superior to other modalities in defining tumor extent and delineating the surrounding anatomy. CONCLUSIONS: Magnetic resonance imaging is the modality of choice for studying subependymomas. The diagnosis should be placed among differential considerations for intraventricular tumors.

Adult↗
PubMedDate not supplied

MR imaging of the infrapatellar fat pad of Hoffa.

The infrapatellar fat pad of Hoffa is an intracapsular structure that is routinely visualized on magnetic resonance images of the knee. Because disease in this region is not uncommon, it is important to be familiar with the various pathologic entities that may occur here. Abnormalities that are intrinsic to this fat pad include Hoffa disease, intracapsular chondroma, localized nodular synovitis, postarthroscopy and postsurgery fibrosis, and shear injury. In addition, the infrapatellar fat pad may be involved secondarily from extrinsic processes, including articular disorders (eg, joint effusion, intraarticular bodies, meniscal cyst, ganglion cyst, cyclops lesion), synovial abnormalities (eg, pigmented villonodular synovitis; hemophilia; synovial hemangioma; primary synovial chondromatosis; chondrosarcoma; lipoma arborescens; rheumatoid, seronegative, and septic arthritis; arthritis associated with inflammatory intestinal disorders; synovitis associated with primary osteoarthritis), and anterior extracapsular abnormalities. The approach to pathologic processes involving the infrapatellar fat pad of Hoffa is simplified when one is familiar with regional anatomy and possible differential diagnostic considerations.

Adipose Tissue↗
PubMedDate not supplied

Evaluation of lower back pain with bone scintigraphy and SPECT.

Bone scintigraphy and single photon emission computed tomography (SPECT) may be performed for evaluation of lower back pain, especially when a bone abnormality is suspected. Various patterns of tracer activity based on precise identification of the anatomic location of increased uptake may be observed and used to evaluate bones and joints. Lesions centered about the disk space and vertebral body include spondylodiskitis, metastatic disease, vertebral body fracture, and degenerative disease (disk disease, spondylosis deformans). In diskitis, tracer uptake has a vertical orientation. Metastatic involvement should be suspected in solitary lesions evaluated with SPECT when the area of increased uptake extends from the vertebral body into the pedicle. Fractures are seen on planar and SPECT images as a linear, horizontally oriented area of increased uptake centered in the vertebral body. In degenerative disease, increased uptake is centered about the disk space and may be seen in and project beyond the surface of the vertebral body. Lesions of the posterior arch (comprising the pedicle, lamina, and facet joints) include spondylolysis, pedicle lesions, osteoarthritis of the facet joints, and fracture of the transverse process. Scintigraphy may help differentiate long-standing asymptomatic spondylolysis from ongoing disease. In osteoarthritis of the facet joints, SPECT may be used to select patients to be treated with therapeutic injections. Increased uptake in the transverse process most often indicates a fracture, although tumors may also occur in this location. These findings at planar bone scintigraphy and SPECT allow differentiation of common pathologic conditions and can lead to a specific diagnosis.

Humans↗