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Biomedical subjects

D Resnick

Publications and source records attributed to D Resnick.

At least 217 records · Page 12Linked to original sources
PubMed1992

The mushroom femoral head. A radiographic investigation.

RATIONALE AND OBJECTIVES: In 1913, anthropologist Ales Hrdlicka described a number of femora as having "mushroom heads," a deformity he attributed to arthritis deformans. The authors have attempted to define the cause of this condition. METHODS: Forty of 41 femora with "mushroom" femoral heads collected by Hrdlicka were grossly inspected and examined with plain radiographs and with computed tomography. Femoral neck angulation and degree of anteversion were determined. RESULTS: Three distinct categories were established: group I, those specimens with normal angulation and short femoral necks; group II, those with varus angulation and short femoral necks; and group III, those with normal-sized femoral necks and normal femoral neck angulation. No correlation was found between degree of anteversion and the categories. Additionally, most of the mushroom deformities were related to osteophyte formation. CONCLUSIONS: Most of the changes in the femora were the result of osteoarthritis. Two groups showed evidence of growth disturbances that occurred early in life. The changes in the second group were similar to those seen in Legg-Calvé-Perthes disease.

Epiphyses, Slipped↗
PubMed1992

Chronic wrist pain: spin-echo and short tau inversion recovery MR imaging and conventional and MR arthrography.

The accuracy of T1-, proton-density-, and T2-weighted magnetic resonance (MR) imaging sequences and gadolinium-enhanced MR arthrography in evaluation of the triangular fibro-cartilage complex (TFCC) and the scapholunate (SL) and lunotriquetral (LT) ligaments was studied in 15 patients with chronic wrist pain. Arthrography and arthroscopy were used as standards of reference. Twelve patients also underwent imaging with short tau inversion recovery (STIR) sequences. MR imaging was more reliable in evaluation of the morphology of the TFCC and SL ligament than in that of the LT ligament. With arthrography as the standard, sensitivity was 0.721, specificity was 0.947, and accuracy was 0.887 for the TFCC; these values were 0.500, 0.864, and 0.765 for the SL ligament and 0.519, 0.455, and 0.490 for the LT ligament. No visualization of the SL ligament indicated a tear, but this sign was not helpful in evaluation of the LT ligament. Fluid in the distal radioulnar joint had a high association with TFCC tears. Accuracy with MR arthrography was higher than with the other sequences. STIR images were effective in evaluation of the TFCC. The combination of proton-density-and T2-weighted images appears to be useful because morphologic characteristics and the presence of fluid can be evaluated.

Arthrography↗
PubMed1992

Rotator cuff disease: assessment with MR arthrography versus standard MR imaging in 36 patients with arthroscopic confirmation.

Standard proton-density- and T2-weighted magnetic resonance (MR) imaging and MR arthrography were used to depict rotator cuff disease in 36 shoulders in 36 patients; the findings were compared with arthroscopic findings in every patient. In 19 rotator cuffs normal at arthroscopy, MR arthrography revealed no tear in 16 patients, a partial tear in one patient, and a full-thickness tear in two patients. Standard proton-density- and T2-weighted images were normal in 15 of these patients and revealed a partial tear in two patients and a full-thickness tear in two patients. In 13 partial tears found at arthroscopy, MR arthrography showed a partial tear in six patients, no tear in five patients, and a full-thickness tear in two patients; standard MR imaging revealed a partial tear in one patient, no tear in 10 patients, and a full-thickness tear in two patients. All four full-thickness tears proved with arthroscopy were correctly diagnosed with both MR imaging methods. The main advantage of MR arthrography was better depiction of partial tears in the articular surface.

Adolescent↗
PubMed1992

Meniscal changes in the elderly: correlation of MR imaging and histologic findings.

In elderly patients, degenerative changes of the meniscus are common and may mimic a tear. The magnetic resonance (MR) image findings of 179 meniscal sections in 20 cadaver knees were correlated with the histologic and gross pathologic findings. The sensitivity of standard T1-weighted spin-echo images and their corresponding meniscal windows in depicting meniscal tears was 80.6%, specificity was 72.4%, and accuracy was 76.7%. These results are not as good as results reported previously. A major difficulty is the occurrence of grade 3 meniscal signal intensity and diffuse intrameniscal signal intensity in torn and intact menisci. MR imaging in elderly patients, however, is still useful in the diagnosis of meniscal abnormalities. Normal low signal intensity depicted within a meniscus at MR imaging and changes in grades 1 and 2 intrameniscal signal intensity are reliable signs of an intact meniscal surface. Grade 3 and diffuse meniscal signal intensities do not allow a specific diagnosis; menisci with these characteristics should be described as degenerated with a high probability of a tear.

Age Factors↗
PubMed1992

The deep lateral femoral notch: an indirect sign of a torn anterior cruciate ligament.

Magnetic resonance (MR) imaging has shown that tears of the anterior cruciate ligament (ACL) are frequently accompanied by meniscal and osseous injuries. Abnormalities of the cartilage overlying the lateral femoral condylopatellar sulcus (notch) also have been noted during arthrotomy of ACL-deficient knees. In this study, the appearance of this sulcus on MR images and the depth of the sulcus on conventional radiographs are compared in patients with normal and torn ACLs to determine whether a deep sulcus is a useful indirect sign of a torn ACL. In 62 patients with clinically and/or arthroscopically confirmed normal ACLs, the mean depth of the lateral femoral sulcus was 0.45 mm (range, 0.0-1.2 mm) compared with 0.89 mm (range, 0.0-5.0 mm) in 41 patients with clinically and/or arthroscopically confirmed ACL tears (significant at the 5% level). No patient with a normal ACL had a sulcus greater than 1.2 mm in depth. A sulcus deeper than 1.5 mm is equivalent to 3 standard deviations above the mean and was a reliable indirect sign of a torn ACL.

Adolescent↗
PubMed1992

Hill-Sachs lesion: comparison of detection with MR imaging, radiography, and arthroscopy.

Magnetic resonance (MR) imaging has proved to be a valuable method for documenting Hill-Sachs lesions. The authors retrospectively analyzed the diagnostic interpretations at plain film radiography, arthroscopy, and MR imaging in 76 patients. The analysis revealed that neither radiography nor arthroscopy displayed the lesion with sufficient accuracy to represent a true standard of reference for the evaluation of MR imaging in the diagnosis of the Hill-Sachs lesion. The data from the diagnostic interpretations were analyzed in three ways, each of which revealed that findings at MR imaging were more helpful than findings at radiography and/or arthroscopy in the diagnosis of the Hill-Sachs lesion. When the agreement of findings in two or three methods was used to assign a final diagnosis, MR imaging resulted in sensitivity of 97%, specificity of 91%, and accuracy of 94% in the detection of Hill-Sachs lesions.

Adolescent↗
PubMed1992

Can burst fractures be predicted from plain radiographs?

Plain radiographs of 67 acute spinal compression fractures in 49 patients were analysed by subjective and objective criteria, using CT scans as the diagnostic standard for the diagnosis of burst fracture. Discriminant analysis correctly predicted the type of fracture in 88% of cases. Burst fractures, however, were almost as frequently misdiagnosed as being wedge compression fractures using this technique, compared with the reading of 25 films from patients without previous information. A quarter of the injuries would have been misdiagnosed had reliance been placed solely on the plain radiographs. CT scans of all patients with acute spinal compression fractures should be considered to decrease this potentially serious diagnostic error.

Diagnosis, Differential↗
PubMed1992

Craniovertebral junction: normal anatomy with MR correlation.

The anatomy of the craniovertebral junction, although complex, may be well visualized by routine MR imaging. This essay discusses the anatomy of the complex articulations of the craniovertebral junction. Representative MR images and gross anatomic photographs are presented to illustrate the intricate ligamentous and articular anatomy. Knowledge of the normal anatomy of the occipitoatlantoaxial region is necessary in order to understand the common disorders that affect this area. The most common disorders are trauma and arthropathies, but also include congenital abnormalities and neoplasm. The resultant abnormal mechanics may lead to neurologic sequelae or pain.

Atlanto-Axial Joint↗
PubMed1992

Width of the articular cartilage of the hip: quantification by using fat-suppression spin-echo MR imaging in cadavers.

OBJECTIVE: Use of MR imaging to measure the width of the articular cartilage has not been thoroughly investigated. The value of a selective fat-suppression spin-echo sequence in the quantitative assessment of articular cartilage of the hip was studied in cadavers. MATERIALS AND METHODS: Sagittal and coronal images were acquired in 10 cadaveric hips (age range at time of death, 62-81 years). On the coronal and sagittal MR images that were closest to the center of the femoral head, marks were placed every 30 degrees, with the midpoint of the femoral head used as a reference. Cartilage thickness was measured in 123 resulting locations. Sixty-three positions included both femoral and acetabular cartilages, and 60 positions included femoral cartilage without an acetabular counterpart. The findings were compared with corresponding anatomic sections. RESULTS: For the 60 locations containing only femoral cartilage, significant correlation between MR and anatomic sections was found (Pearson correlation coefficient = .34, p = .0089). Of the 63 locations containing both femoral and acetabular cartilages, the two cartilage layers could be differentiated on the MR images in 50 locations. In these 50, the MR and anatomic measurements of the femoral cartilage correlated significant (r = .58, p less than or equal to .0001). Measurements of the acetabular cartilage in these 50 locations yielded no significant correlation (r = .25, p = .08). When the entire cartilage (femoral plus acetabular) was measured in all 63 locations, the correlation between MR and anatomic measurements was .29 (p = .02). The correlation coefficients obtained in this investigation indicate considerable scattering of the data. CONCLUSION: Our results show that measurements of articular cartilage thickness of the hip on fat-suppression spin-echo MR images are not sufficiently accurate to be of clinical value.

Aged↗
PubMed1992

The cruciate ligaments of the knee: correlation between MR appearance and gross and histologic findings in cadaveric specimens.

OBJECTIVE: Using anatomic and histologic correlation, we investigated the reasons for differences in the MR signal intensity between the normal anterior and posterior cruciate ligaments and for the focally increased signal intensity within these ligaments occasionally found in elderly patients. MATERIALS AND METHODS: The MR images of 18 anterior and 20 posterior cruciate ligaments obtained from cadavers (age at death, 56-88 years old; mean, 74 years) were evaluated blindly. Their overall signal intensity and focal regions of increased signal were noted. The findings then were correlated with corresponding anatomic and histologic sections. RESULTS: The anterior cruciate ligament had greater signal intensity than did the posterior cruciate ligament in 15 of 18 knees and had comparable signal intensity in three knees. No histologic basis to explain the different MR appearances of the anterior and posterior cruciate ligaments was found. Rather, differences in macroscopic anatomy appeared to be the best explanation. In the posterior cruciate ligament, the fibers were parallel, whereas they were diverging and twisted in the anterior cruciate ligament, causing volume-averaging artifacts. A focal area of signal increase was found in 29 of the 38 ligaments. In 17 of these 29 ligaments, mucoid and/or eosinophilic degeneration was found that appeared to have caused the focal MR signal change. In nine ligaments without focally increased signal on the MR images, only one had histologic evidence of degeneration. The predictive value of an abnormal finding on MR was 59%, and the predictive value of a normal finding on MR was 89%. The relationship between increased signal on MR and histologic degeneration was statistically significant (chi 2 test, p = .0126). CONCLUSION: The differences in the MR appearances of the anterior and posterior cruciate ligaments probably are due to differences in gross architecture. Increased MR signal within the cruciate ligaments occurring in elderly patients often can be attributed to degenerative changes.

Aged↗
PubMed1992

Knee effusion: normal distribution of fluid.

Although visualization of articular fluid on MR images of the knee is common, no specific MR criteria that enable assessment of the quantity of the effusion have been established. We performed MR of three cadaveric knee specimens after the instillation of increasingly large volumes of fluid and studied the distribution of the fluid. When 4 ml of fluid was injected, the anteroposterior diameter of the suprapatellar recess was 4 mm on midline sagittal MR images and 10.0-12.5 mm on lateral sagittal MR images, corresponding to the usual routine radiographic criteria for a knee effusion.

Humans↗
PubMed1992

Injuries of the superior portion of the glenoid labrum involving the insertion of the biceps tendon: MR imaging findings in nine cases.

The goal of this investigation was to describe the MR appearance of traumatic fraying or detachment of the superior portion of the glenoid labrum including the insertion of the tendon of the long head of the biceps. This condition is caused either by an acute injury or by repeated overhead motion during participation in sports. In nine patients with such a lesion, the arthroscopic report and MR images were available for review. These patients were 22-64 years old (mean, 38). In four patients only fraying was noted during arthroscopy, in four patients the superior part of the labrum was detached together with the insertion of the biceps tendon, and in one case there was a bucket-handle tear of the superior portion of the labrum. The MR images were retrospectively evaluated by three osteoradiologists in conference. Signal changes within the labrum and detachment of the labrum were noted, and the findings were compared with the results of arthroscopy. MR imaging did not allow recognition of simple fraying. In two of the five cases with arthroscopic findings of detachment of the superior labrum from the glenoid rim, differentiation between complete and partial labral detachments was not possible even with MR arthrography. However, in these cases the patient's age and history led to the correct diagnosis. We conclude that early traumatic abnormalities of the superior portion of the labrum cannot be detected with MR imaging. Complete detachment, however, can be demonstrated if the patient's age and history are taken into consideration.

Adult↗
PubMed1991

The type I and type II bovine scavenger receptors expressed in Chinese hamster ovary cells are trimeric proteins with collagenous triple helical domains comprising noncovalently associated monomers and Cys83-disulfide-linked dimers.

Scavenger receptors have been implicated in the development of atherosclerosis and other macrophage-associated functions. The structures and processing of type I and type II bovine macrophage scavenger receptors were examined using polyclonal anti-receptor antibodies. Pulse/chase metabolic labeling experiments showed that both types of scavenger receptors expressed in Chinese hamster ovary (CHO) cells behaved as typical cell surface membrane glycoproteins. They were synthesized as endoglycosidase H-sensitive precursors which were converted to endoglycosidase H-resistant mature forms expressed on the cell surface. The reduced precursor and mature forms were doublets on sodium dodecyl sulfate-gel electrophoresis, primarily because of heterogeneous N-glycosylation. The approximate molecular sizes were: type I precursor, 65/63 kDa; type I mature, 82/76 kDa; type II precursor, 57/53 kDa; and type II mature, 72/65 kDa. During post-translational processing, the cysteine-rich C terminus (SRCR domain) of some of the type I receptors was proteolytically removed to form a relatively stable, approximately 69-kDa degradation product. Type II receptors differ from type I receptors in that they do not have SRCR domains and an analogous proteolytic cleavage was not observed. Several experiments provided strong evidence that the Gly-X-Y-repeat domains in the scavenger receptors oligomerize into collagenous triple helices. For example, alpha,alpha'-dipyridyl, an inhibitor of the collagen-modifying enzymes prolyl and lysyl hydroxylases, interfered with both the kinetics and nature of post-translational receptor processing, and both precursor and mature forms of the receptors in intact cells could be cross-linked with difluorodinitrobenzene into reduction-resistant trimers. In intact cells, precursor receptor trimers (type I, 198 kDa; type II, 176 kDa) were assembled in the endoplasmic reticulum by the noncovalent association of monomers and Cys83-disulfide-linked dimers (type I, 129 kDa; type II, 119 kDa). When cells were lysed in the absence of the sulfhydryl trapping agent iodoacetamide, oxidation of the side chain of Cys17 in the cytoplasmic domain leads to the artifactual formation of reduction-sensitive covalently linked trimers. The approximate masses of the mature dimer and trimer forms were 162 and 237 kDa for type I receptors and 147 and 219 kDa for type II receptors. Cys83-disulfide-linked dimer formation was not required for function because mutant receptors (Cys83----Gly83) assembled into trimers of noncovalently associated monomers and exhibited normal receptor activity. Treatment of cells with difluorodinitrobenzene cross-linked some of the receptors into complexes larger than trimers, raising the possibility that the trimers may assemble into higher order oligomers.

2,2'-Dipyridyl↗
PubMed1991

Metastases to bone affected by Paget's disease. A report of three cases.

Three cases of metastatic disease in bone affected by Paget's disease are presented. The literature has been reviewed and a total of 26 similar cases found. The occurrence is rare compared to the frequency of sarcomatous transformation in Paget's disease, and low considering the frequency with which metastatic disease and Paget's disease each affect the elderly. This suggests that pagetic bone may resist the implantation of metastatic tumour cells.

Adenocarcinoma↗