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Biomedical subjects

D Resnick

Publications and source records attributed to D Resnick.

At least 37 records · Page 2Linked to original sources
PubMed2001

Pigmented villonodular synovitis of the hip presenting as a retroperitoneal mass.

We present an unusual case of diffuse pigmented villonodular synovitis (PVNS) of the hip presenting as a large retroperitoneal mass in an asymptomatic 39-year-old man. Initial imaging characteristics and findings on core needle biopsy suggested soft tissue sarcoma. However, incisional biopsy showed findings of PVNS. The patient underwent radical synovectomy and total joint replacement, with no change in the large retroperitoneal component after 15 months of follow-up.

Adult↗
PubMed2001

Dysphagia caused by a fetus-in-fetu in a 27-year-old man.

Mechanical obstruction of the distal esophagus by a fetus-in-fetu is an extremely rare condition that has not been previously reported. We present the case of a 27-year-old man who presented with dysphagia caused by fetus-in-fetu contained within a retroperitoneal cystic cavity. The tumor, noticed since childhood, did not cause any symptoms until a year before presentation when symptoms of dysphagia developed. We propose including this entity in the differential diagnosis of a retroperitoneal mass.

Adult↗
PubMed2001

Atlantoaxial joints: patterns of gadolinium enhancement with MR imaging in normal subjects.

OBJECTIVE: To evaluate normal patterns of enhancement of signal intensity in and about the atlantoaxial joints following intravenous administration of a gadolinium-containing contrast agent. METHODS AND MATERIAL: Fat-suppressed axial T1 weighted SE images were obtained in 12 patients without evidence of inflammmatory arthritis before and immediately after intravenous administration of a gadolinium-containing contrast agent. Patterns of enhancement of signal intensity in and about the atlantoaxial joints were evaluated qualitatively. RESULTS: Four different MR imaging patterns were observed: no enhancement of signal intensity, enhancement in the form of a single punctate region, enhancement in a confluent pattern, and bandlike enhancement. CONCLUSION: Enhancement occurs around the odontoid process in patients without evidence of rheumatoid arthritis (RA). The dividing line between early synovitis and normal enhancement seems broader than expected. The reasons remain unclear and warant further studies.

Adult↗
PubMed2001

Magnetic resonance imaging of the upper extremity: advances in technique and application.

Vast advances in technology have taken place in the field of radiology led by the introduction of magnetic resonance imaging. The added advantages of exquisite soft tissue contrast and multiplanar imaging capabilities have revolutionized the understanding of complex anatomic relationships and diagnoses. The current authors will focus on the introduction of new advances in magnetic resonance imaging of the upper extremity that may prove helpful in the diagnosis and treatment of upper extremity abnormalities.

Arm↗
PubMed2001

In vivo changes after mechanical injury.

Chondrocytes undergo apoptosis in response to mechanical injury in vitro. The current clinical study correlates arthroscopic and magnetic resonance imaging results with biopsy specimens of cartilage from patients with knee injury. Twenty patients were evaluated at a mean 2.7 months after acute knee injury. The mean age of the patients was 32 years and the mean weight was 83 kg. Cartilage lesions were graded separately on magnetic resonance images and arthroscopy in a blinded manner. During arthroscopy, a 1.8 mm diameter biopsy specimen was obtained from the edge of cartilage lesion. The biopsy specimen underwent histologic examination by safranin O staining and detection of chondrocyte apoptosis by the presence of deoxyribonucleic acid fragmentation. There was a positive correlation in 50% (10 of 20) when the presence or absence of cartilage lesions by magnetic resonance imaging was correlated with arthroscopy. All cases of partial thickness or full-thickness cartilage loss that were seen by arthroscopy also were detected by magnetic resonance images. Apoptotic cells were significantly more numerous in biopsy specimens from lesions compared with control biopsy specimens. The findings of reduced cell viability attributable to apoptosis may have profound implications for cartilage repair. This opens potential therapeutic avenues for the treatment of posttraumatic cartilage lesions through apoptosis prevention.

Adult↗
PubMed2001

Assessment of the position of the distal portion of the ulna in lateral projection radiographs of the wrist: analysis of the influence of pronation-supination and flexion-extension on the pisoscaphoid and the ulnotriquetral distances: a cadaver study.

RATIONALE AND OBJECTIVES: Accurate assessment of the distal radioulnar joint is of paramount importance for the detection of possible dislocation or subluxation. Using a cadaveric model, the authors attempted to establish a quantitative method that would allow identification of normal and abnormal distal radioulnar joint anatomy on well-positioned and rotated conventional radiographs. METHODS: Four cadaveric wrists, in which subsequent sectioning confirmed the absence of disease, and one cadaveric wrist with a circumscribed lesion of the triangular fibrocartilaginous complex were studied. Defined movements in flexion and extension (+/- 10 degrees, 20 degrees, 30 degrees ) and in pronation and supination (+/- 10 degrees, 20 degrees, 30 degrees ) as well as combined flexion/extension and pronation/supination were performed. The ulnotriquetral and the pisoscaphoid distances were assessed in each position. Correlation with cryosections was achieved. RESULTS: A strong linear correlation between the degree of pronation or supination and the pisoscaphoid and ulnotriquetral distances was noted. Flexion and extension produced no significant effect on the pisoscaphoid distance, but a defined shift of the ulnotriquetral distance occurred with increasing flexion and extension. CONCLUSIONS: If all parameters are taken into account, this correlation aids in estimating the degree of possible malpositioning of the wrist during radiography and the degree of subluxation of the distal radioulnar joint. Tabular data with parameters to correct for instances of malrotated images and to estimate the extent of dislocation or malrotation of the distal radioulnar joint are provided.

Cadaver↗
PubMed2001

Greater trochanter of the hip: attachment of the abductor mechanism and a complex of three bursae--MR imaging and MR bursography in cadavers and MR imaging in asymptomatic volunteers.

PURPOSE: To evaluate trochanteric anatomy with magnetic resonance (MR) imaging, bursography, MR bursography, and anatomic analysis. MATERIALS AND METHODS: T1-weighted and fat-saturated T2-weighted (transverse, sagittal, coronal, and coronal oblique planes) MR imaging of the greater trochanter was performed in 10 cadaveric hips and 12 hips of asymptomatic volunteers. Three bursae comprising the trochanteric bursa complex were injected, and conventional radiography and MR imaging were performed. The specimens were sectioned for anatomic analysis, corresponding to the MR imaging planes. Tendon attachments and bursal localization were related to the facets of the greater trochanter. RESULTS: The bony surface of the greater trochanter consists of four facets: anterior, lateral, posterior, and superoposterior. The gluteus medius muscle attaches to the superoposterior and lateral facets. The gluteus minimus muscle attaches to the anterior facet. The trochanteric bursa covered the posterior facet and the lateral insertion of the gluteus medius muscle. The subgluteus medius bursa was located in the superior part of the lateral facet, underneath the gluteus medius tendon. The subgluteus minimus bursa lies in the area of the anterior facet, underneath the gluteus minimus tendon, medial and cranial to its insertion, and extends medially covering the distal anterior part of the hip joint capsule. The trochanteric bursa is delineated with fat on both sides and can be seen on transverse nonenhanced T1-weighted images as a fine line curving around the posterior part of the trochanter. CONCLUSION: MR imaging and bursography provide detailed information about the anatomy of tendinous attachments of the abductor muscles and the bursal complex of the greater trochanter.

Adult↗
PubMed2001

Cervical spine: postmortem assessment of accident injuries--comparison of radiographic, MR imaging, anatomic, and pathologic findings.

PURPOSE: To assess the ability of postmortem radiography and magnetic resonance (MR) imaging to depict occult cervical spine injuries as compared with anatomic and pathologic findings. MATERIALS AND METHODS: The cervical spines of 10 adult accident victims underwent radiography and MR imaging, with T1-weighted, fast spin-echo T2-weighted, and four gradient-echo pulse sequences. The frozen specimens were cut into 3-mm-thick slices (sagittal plane) and photographed, and microfocus radiographs were obtained. Imaging findings were compared with the anatomic and pathologic findings. RESULTS: Eight of the 10 specimens had 28 posttraumatic lesions: three fractures (two missed at the initial MR imaging reading), 10 facet joint capsule lesions with bleeding, five soft-tissue and ligament lesions, eight disk lesions, and two spinal cord lesions. Radiography depicted one lesion (4%). Two partial ruptures of the anterior annulus fibrosus were depicted at only MR imaging. Initially, 11 of 28 lesions were detected on MR images; retrospectively, 17 of 28 lesions were correlated with anatomic findings. CONCLUSION: Soft-tissue and intervertebral disk and ligament injuries account for 89% (25 of 28) of posttraumatic cervical spine lesions detected on postmortem images. Occult lesions, including apophyseal joint injuries, were found in clinically noninjured cervical spines. MR imaging was limited in the depiction of discrete lesions when T1-weighted non-fat-saturated, fast spin-echo T2-weighted, and gradient-echo pulse sequences were used.

Adult↗
PubMed2001

Intermetatarsal spaces: analysis with MR bursography, anatomic correlation, and histopathology in cadavers.

PURPOSE: To describe the normal magnetic resonance (MR) imaging-depicted anatomy of the intermetatarsal spaces, with emphasis on the MR imaging appearance of the intermetatarsal bursae, and to correlate the MR findings with those seen in anatomic sections and at histopathologic analysis. MATERIALS AND METHODS: Conventional radiography and pre- and postcontrast T1-weighted and fat-saturated T1-weighted spin-echo MR imaging were performed in 32 intermetatarsal spaces in eight human cadaveric feet. The cadaveric specimens were sectioned in planes corresponding to those at MR imaging for anatomic correlation. The intermetatarsal space anatomy was analyzed. Histopathologic examinations of the bursae were performed. RESULTS: The intermetatarsal spaces were located in the forefoot between two metatarsal heads, below and above the deep transverse metatarsal ligament (DTML) that separated the spaces into two levels. The superior level contained the synovial bursa, the plantar and dorsal interosseous muscles and tendons, and the collateral ligament complexes of the metatarsophalangeal joints. The inferior level contained lumbrical muscles and neurovascular bundles. The bursae extended distally to the DTML in the second and third spaces close to the neurovascular bundles and did not extend beyond the DTML in the first and fourth spaces. In the first intermetatarsal space, the bursa had a specific appearance as it coursed along the adductor hallucis tendon as a tendon sheath. Histopathologic examination of the bursae revealed a single layer of attenuated cells. CONCLUSION: MR bursography provided detailed information about the intermetatarsal anatomy, especially the intermetatarsal bursae.

Aged↗
PubMed2001

Selective nerve root blocks for the treatment of sciatica: evaluation of injection site and effectiveness--a study with patients and cadavers.

PURPOSE: To relate different types of radiographic contrast material distributions to anatomic compartments by using cadaveric specimens and to relate the injection site to treatment-induced discomfort and therapeutic effect. MATERIALS AND METHODS: The contrast material distributions of selective nerve root blocks (SNRBs) in 36 patients (13 women, 23 men; mean age, 52 years; age range, 22-88 years) were graded by two radiologists in conference as type 1 (tubular appearance), type 2 (nerve root visible as filling defect), or type 3 (nerve root not visible). These patterns were correlated with pain reduction after 15 minutes and 2 weeks (with a visual analogue scale of 100-mm length). In addition, 30 nerve roots were injected with iodine-containing contrast material and blue dye in three cadaveric specimens. Radiographs were compared with anatomic sections. RESULTS: After 15 minutes and 2 weeks, 75% and 86% of the patients, respectively, reported pain relief. Mean pain relief length after 15 minutes for type 1 distribution was 60 mm; for type 2, 44 mm; and for type 3, 22 mm; and after 2 weeks, it was 34 mm for type 1, 31 mm for type 2, and 57 mm for type 3. There was no correlation between early and late response. Pain during intervention was less pronounced in type 2 injection, compared with type 1 (P = .002). On the basis of anatomic sections, type 1 injection was intraepineural; type 2, extraepineural; and type 3, paraneural. CONCLUSION: Therapeutic SNRB is effective in sciatica, but early response does not predict the effect after 2 weeks. Type 1 injections are more painful than type 2 injections.

Adult↗
PubMed2001

Shell osteochondral allografts of the knee: comparison of mr imaging findings and immunologic responses.

PURPOSE: To define the magnetic resonance (MR) imaging appearance of shell osteochondral allografts of the knee and compare the MR findings with antibody responses. MATERIALS AND METHODS: Thirty-six grafts were evaluated with a 1.5-T unit with T1-, intermediate-, and T2-weighted, and three-dimensional spoiled gradient-recalled MR imaging at 3, 6, 12, 24, and/or 36 months after surgery. Nineteen patients underwent imaging serially. Two osteoradiologists scored by consensus host marrow edema, thickness of graft-host interface, signal intensity of graft marrow, cyst formation, joint effusion, articular cartilage defects, and surface collapse. Patients were divided into antibody-positive (AP) (n = 11) and antibody-negative (AN) (n = 25) groups evenly distributed across the different time points on the basis of results of anti-human leukocyte antigen antibody screening. MR findings for the two groups were compared. RESULTS: AP patients demonstrated greater mean edema (P<.002), thicker interface (P<.03), and more abnormal graft marrow (P<.04) than AN patients, and they had a higher proportion of surface collapse (P<.03). CONCLUSION: Humoral immune responses were associated with more inflammation and less complete incorporation after allograft placement. MR imaging shows promise as a surrogate biomarker for success of shell osteochondral allograft implantation.

Adolescent↗
PubMed2001

Schmorl nodes of the thoracic and lumbar spine: radiographic-pathologic study of prevalence, characterization, and correlation with degenerative changes of 1,650 spinal levels in 100 cadavers.

PURPOSE: To investigate the frequency and characteristics of Schmorl nodes in an elderly population and to correlate these findings with degenerative spinal changes. MATERIALS AND METHODS: Cadaveric thoracic and lumbar spines were removed at autopsy (mean age at death, 68.2 years; range, 43-93 years). Parasagittal sections of approximately 5-mm thickness were obtained and radiographed. At each of 3,300 endplates from T1 to L5, the presence of Schmorl nodes was noted. Vertebral endplate contour was analyzed, and abnormalities of the discovertebral junction were noted. The height of each interspace was measured, and the presence or absence of vacuum phenomena and spondylosis was recorded. RESULTS: Schmorl nodes were found in 58 specimens and were multiple in 41. Of 3,300 vertebral endplates, 225 revealed Schmorl nodes: 88 cranial and 137 caudal. More than 182 were between T7 and L2. Schmorl nodes correlated with disk space loss (P <.001) but not with evidence of advanced disk degeneration: marked disk space loss (P =.53), vacuum phenomena (P =.82), or discogenic sclerosis or erosion (P =.35). Schmorl nodes were associated with claw (P <.001) but not traction (P =.72) osteophytes. Straight (P <.001) and fractured (P <.001) vertebral endplates were associated with Schmorl nodes. CONCLUSION: Schmorl nodes are common in the spines in an elderly population, with a frequency similar to that in a younger population. Schmorl nodes are associated with moderate but not advanced degenerative changes. Geometric observations regarding the vertebral endplates support the concept that Schmorl nodes are caused by an abnormality of the discovertebral junction.

Adult↗
PubMed2001

Pathogenesis of the Segond fracture: anatomic and MR imaging evidence of an iliotibial tract or anterior oblique band avulsion.

PURPOSE: To demonstrate the normal anatomy of the stabilizing structures of the lateral aspect of the knee and to investigate pathogenesis of the Segond fracture, with emphasis on the iliotibial tract (ITT) and anterior oblique band (AOB) of the fibular collateral ligament. MATERIALS AND METHODS: Dissection of the region of the AOB, ITT, and lateral capsular ligament was performed in three cadaveric knees, with placement of gadopentetate dimeglumine-filled tubes along their course and tibial insertions. These knees, in addition to three nondissected knees, were studied with magnetic resonance (MR) imaging by using standard and specialized oblique planes. Specimen sectioning provided anatomic correlation. Retrospective review of radiographs and MR images in 17 patients with acute Segond fractures was performed, and the relationship between the fragment and the demonstrated lateral supporting structures of the knee was noted. RESULTS: Anatomic dissection and MR imaging of the cadaveric knees demonstrated a broad tibial insertion of the ITT, with fibers extending posterior to the Gerdy tubercle. A firm band of tissue, the AOB, extended from the fibular collateral ligament to the midportion of the lateral tibia, the typical site of a Segond fracture. The lateral capsular ligament proved to be a mere thickening of the capsule, inserting at the lateral tibia. Clinical analysis of acute Segond fractures confirmed the frequent attachment of the ITT and AOB to the avulsed fragment. CONCLUSION: Anatomic and clinical findings suggest that fibers of the ITT and AOB are important factors in the pathogenesis of the Segond fracture.

Adolescent↗
PubMed2001

Tarsal sinus: arthrographic, MR imaging, MR arthrographic, and pathologic findings in cadavers and retrospective study data in patients with sinus tarsi syndrome.

PURPOSE: To evaluate the tarsal sinus by using different imaging techniques and specialized planes. MATERIALS AND METHODS: Magnetic resonance (MR) imaging of the tarsal sinus was performed in 10 cadavers. Conventional arthrography of the anterior and posterior subtalar joints was then performed. Tarsal sinus ligaments were evaluated further on initial and reconstructed MR arthrograms along and perpendicular to their axes. Pathologic correlation was performed in five specimens suspected of having tarsal sinus lesions on the basis of initial imaging findings. In 37 patients with a clinical diagnosis of sinus tarsi syndrome, MR images of the ankle were obtained before and after intravenous gadolinium-based contrast material administration and were reviewed to verify the integrity of the tarsal sinus ligaments. RESULTS: Two complete and three partial cervical ligament (CL) tears and one complete interosseous talocalcaneal ligament (ITCL) tear were diagnosed with MR imaging. Only one complete and one partial CL tear were seen after evaluation of both initial and reconstructed MR arthrograms and confirmed with pathologic correlation. In 18 patients, the diagnosis was confirmed at MR imaging, which depicted ITCL and CL tears in 11 patients, isolated CL tears in three patients, ganglia in three patients, and pigmented villonodular synovitis in one patient. CONCLUSION: Cadaveric study results indicate that initial and reconstructed MR arthrograms along and perpendicular to the ligament axes are potentially useful for further evaluation of individual tarsal sinus structures.

Adult↗
PubMed2001

Intramedullary osteosclerosis: imaging features in nine patients.

PURPOSE: To determine the conventional radiographic, computed tomographic (CT), magnetic resonance (MR) imaging, scintigraphic, and histologic features of intramedullary osteosclerosis and to review the clinical features. MATERIALS AND METHODS: Nine female patients with leg pain and imaging features indicative of intramedullary sclerosis were seen during a 25-year period. None of the patients had a history of trauma or infection, familial bone disease, or related abnormal laboratory findings. Imaging studies included radiography (n = 9), CT (n = 4), MR imaging (n = 5), and skeletal scintigraphy (n = 5). Histologic correlation was available in five patients. RESULTS: Sixteen bone lesions (midtibia, n = 14; distal fibula, n = 1; and proximal femur, n = 1) were evident. Both lower extremities were involved in seven patients, and a single extremity was involved in two. Intramedullary sclerosis was present, as was cortical thickening, mainly in the diaphysis of the long bones, without extensive periosteal reaction or soft-tissue involvement. Findings at bone scintigraphy were positive in all lesions. Histologic analysis showed nonspecific changes of markedly sclerotic bone with a variable degree of mineralization and maturity. CONCLUSION: Intramedullary osteosclerosis is a distinct disorder that typically affects the diaphysis of one or both tibiae in women. Characteristic imaging findings, when coupled with clinical information, allow precise diagnosis.

Adolescent↗
PubMed2001

Polydioxanone biodegradable pins in the knee: MR imaging.

OBJECTIVE: Biodegradable solid implants have been developed as an alternative to metallic orthopedic fixation. In animal models, implants degrade within and are replaced by bone. This study documents the resorption of these devices in human patients with MR imaging. SUBJECTS AND METHODS: One hundred seventy-five 1.3-mm biodegradable pins made of polydioxanone were used to secure a total of 59 osteochondral allografts of the knee. Patients with the pins underwent scanning on a 1.5-T unit with 3.3- to 4-mm contiguous T1-weighted spin-echo (TR/TE, 600/15), fat-saturated proton density-weighted (3000/40), T2-weighted fast spin-echo (3000/63), and three-dimensional spoiled gradient-recalled (47/7; flip angle, 60 degrees ) sequences at 3, 6, 12, 24, or 36 months after surgery. Eighty-nine pins were imaged on multiple occasions. Two osteoradiologists interpreted the MR examinations. RESULTS: More than 80% of the pin channels were visible at 3 and at 6 months after surgery. By 24 months, only 20% of the pin channels were visible, with the remainder having been replaced by bone. At 3 months, nearly 40% of the pins were associated with adjacent marrow edema. Edema generally diminished, involving less than 20% of pins at later time points. Focal cartilage defects were evident at 32% of the pin insertion sites during the first 6 months, but these defects were present in only 4% of the insertion sites thereafter. CONCLUSION: Biodegradable polydioxanone pins usually resorb completely by 24 months. Marrow edema, presumably representing inflammation related to pin resorption, is infrequent and tends to resolve. Cartilage defects related to pin placement heal spontaneously.

Absorbable Implants↗