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Biomedical subjects

S McCarthy

Publications and source records attributed to S McCarthy.

At least 91 records · Page 5Linked to original sources
PubMed1991

MR appearance of painful conditions of the ankle.

Magnetic resonance (MR) imaging was performed in 60 patients with ankle pain who were suspected of having various soft-tissue or osseous abnormalities. Results of conventional radiographs had been normal or inconclusive. Soft-tissue disorders depicted by MR imaging included tendon and ligament tears, tendinitis, tenosynovitis, and plantar fasciitis. Osseous conditions demonstrated by MR imaging included osteochondritis dessicans, infarcts, bone bruises, stress fractures, tarsal coalition, and osteoid osteoma. The authors believe that MR imaging is useful in the assessment of a variety of painful ankle disorders.

Adult↗
PubMed1991

[Deep mycoses observed in New Caledonia. Evaluation of observations from the laboratory of pathologic anatomy of the Pasteur Institute of New Caledonia 1975-1990].

All cases of deep mycotic diseases observed between 1975 and 1989 in the Laboratory of Anatomical Pathology at Nouméa's Pasteur Institute have been studied retrospectively together with all available data concerning this pathology both in New Caledonia and the Pacific area. During the period under review, two cases of histoplasmosis, 4 of actinomycosis, 3 sporotrichosis, 5 mycetoma and 5 chromoblastomycosis were recorded in New Caledonia. Clinical and histological data appear to be identical to those observed in other Pacific Islands. Diagnosis is most usually supported only by histological examination and, thus, for future studies it is vital that specific mycologic culture of all cases be carried out.

Actinomycosis↗
PubMed1990

Relation of serum lipoprotein(a) concentration and apolipoprotein(a) phenotype to coronary heart disease in patients with familial hypercholesterolemia.

Familial hypercholesterolemia carries a marked increase in the risk of coronary heart disease (CHD), but there is considerable variation between individuals in susceptibility to CHD. To investigate the possible role of lipoprotein(a) as a risk factor for CHD, we studied the association between serum lipoprotein(a) levels, genetic types of apolipoprotein(a) (which influence lipoprotein(a) levels), and CHD in 115 patients with heterozygous familial hypercholesterolemia. The median lipoprotein(a) level in the 54 patients with CHD was 57 mg per deciliter, which is significantly higher than the corresponding value of 18 mg per deciliter in the 61 patients without CHD. According to discriminant-function analysis, the lipoprotein(a) level was the best discriminator between the two groups (as compared with all other lipid and lipoprotein levels, age, sex, and smoking status). Phenotyping for apolipoprotein(a) was performed in 109 patients. The frequencies of the apolipoprotein(a) phenotypes and alleles differed significantly between the patients with and those without CHD. The allele LpS2, which is associated with high lipoprotein(a) levels, was found more frequently among the patients with CHD (0.33 vs. 0.12). In contrast, the LpS4 allele, which is associated with low lipoprotein(a) levels, was more frequent among those without CHD (0.27 vs. 0.15). We conclude that an elevated level of lipoprotein(a) is a strong risk factor for CHD in patients with familial hypercholesterolemia, and the increase in risk is independent of age, sex, smoking status, and serum levels of total cholesterol, triglyceride, or high-density lipoprotein cholesterol. The higher level of lipoprotein(a) observed in the patients with CHD is the result of genetic influence.

Adult↗
PubMed1990

Scaphoid fractures and Kienbock's disease of the lunate: MR imaging with histopathologic correlation.

Thirteen patients with scaphoid fractures and four patients with Kienbock's disease of the lunate underwent magnetic resonance imaging (MRI) prior to surgery. A total of 28 specimens had MR-histologic correlation. Biopsy specimens obtained by curettage provided pathologic correlation. MRI proved accurate in prospective evaluation of bone viability for both scaphoid fractures and Kienbock's disease. Normal marrow signal was shown to correlate with the presence of osteoid and osteocytes on light microscopy and a surface layer of fluorescence reflecting tetracycline uptake in viable bone. Decreased marrow signal corresponded to non-viable trabeculae with scant osteoid, without osteocytes and no tetracycline labeling. By virtue of its accurate identification of avascular necrosis, MRI may prove valuable in predicting prognosis for patients with scaphoid fractures and Kienbock's disease of the lunate.

Adult↗
PubMed1990

High-field MRI and US evaluation of the pelvis in women with leiomyomas.

Magnetic resonance imaging (MRI) and real-time transabdominal ultrasonography (US) were performed on 23 women with uterine leiomyomas. The uterus, ovaries, and cul de sac were evaluated. Accurate determination of uterine volume was possible in all cases by MRI, but was limited on US in uteri larger than 140 cc. Marked enlargement also prevented visualization of contour abnormalities in eight patients on US, but none on MRI. The endometrial stripe and junctional zone could not be adequately visualized in 21/23 US examinations, whereas they were identified in all 23 MRI (8 normal and 15 distorted). Individual leiomyomas were clearly depicted on 4 US and 19 MR scans, the smallest being 1.1 cm and 0.8 cm, respectively. Of the 31 fibroids present on MRI: 13 were intramural, 4 subserosal, and 14 submucosal. MRI successfully identified 44/46 ovaries as compared to 21/46 on US. Cul de sac fluid was noted in seven women by MRI alone. This data suggests that MRI is superior to US in examination of the entire pelvis in women with leiomyomas.

Adult↗
PubMed1990

Induced current constraints and capacitive effects in inductive nerve stimulation.

A number of studies have reported in vivo and in vitro stimulation of nerves by means of induced currents. We have found that purely inductive stimulation of the frog sciatic nerve and gastrocnemius muscle using unshielded or shielded whole toroids could not be achieved with techniques and EMF intensities and durations consistent with those reported by other investigators. In those instances where stimulation was achieved, our findings suggest that it resulted from capacitive coupling between unshielded toroids and a nerve/grounding electrode. Maximum primary voltages ranged up to 80 V. Corresponding secondary EMF's and pulse durations were as much as 5 V and 100 microseconds, respectively, in different experiments. Stimulating capacitive current densities near the nerve were estimated to be in the range of 100 to 400 mA/cm2, while maximum induced current densities were estimated to be in the range of 10 to 30 mA/cm2 for the same pulse duration.

Animals↗
PubMed1990

Monitoring therapy with a gonadotropin-releasing hormone analog: utility of MR imaging.

The utility of magnetic resonance (MR) imaging in assessing response to therapy with a gonadotropin-releasing hormone (GnRH) analog was assessed in 19 women with uterine leiomyomas and 19 women with endometriosis. There was a significant reduction in individual fibroid volumes at 3 months (P less than .05) and at 6 months (P less than .005) in the drug group, whereas there was no significant change in the placebo group. Vessel conspicuity significantly decreased at 3 months (P less than .02) and at 6 months (P less than .01) in the drug group but not in the placebo group. In the patients with endometriosis, there was a significant decrease (P less than .0006) in the number of endometriomas visualized. Significant changes were also noted in the pelvis in women who were receiving the GnRH analog. After 6 months of therapy, the identifiability of the ovaries was significantly poorer (P less than .05). The authors conclude that the utility of conservative therapy with a GnRH analog can be quantitatively assessed with MR imaging.

Abdominal Neoplasms↗
PubMed1990

Meniscal abnormalities in the asymptomatic population at MR imaging.

Two hundred eighty meniscal horns in 64 asymptomatic volunteers in the 2nd to 8th decades of life were analyzed for meniscal abnormalities. Grade 1, 2, and 3 changes were present in essentially all decades. There was at least a 25% prevalence of meniscal signal abnormalities as early as the 2nd decade. The prevalence of meniscal abnormalities increased sharply with age. The prevalence of all signal abnormalities correlated with age, grade 2 changes having the highest correlation coefficient (+.88). The correlation coefficient for grades 1 and 3 changes were +.60 and +.71, respectively. The posterior horn of the medial meniscus had a significantly higher (P less than .02) prevalence of abnormalities than did the other meniscal locations. There was no significant correlation between subject weight or sex and meniscal signal. The authors conclude that there is a baseline prevalence of meniscal signal in the asymptomatic population.

Adolescent↗
PubMed1990

Gynecologic applications of MRI.

Gynecologic anatomy is consistently depicted with MRI. Abnormal developmental anatomy is also well assessed. In cases of complete or partial vaginal agenesis where ultrasound is equivocal, MRI can be definitive. The various subtypes of uterine anomalies are well delineated with MRI. MRI is the optimal technique in the therapeutic evaluation of leiomyomas, because the number, size, location, and degeneration can be documented. It is particularly useful in the identification of the ovaries in the presence of an enlarged leiomyomatous uterus. Adenomyosis, an often neglected diagnosis, is distinguishable from leiomyomas. In the setting of an equivocal ultrasound, MRI is useful in discerning whether a mass is ovarian or uterine in origin. Endometriosis, a disease routinely diagnosed and staged by laparoscopy, does have a typical MR appearance and therefore can usually be differentiated from other adnexal masses. Dermoids are readily diagnosed with MRI. Other adnexal masses do not have a specific MR appearance and morphologic criteria as used with ultrasound or CT must be relied upon in suggesting whether or not the mass is benign or malignant. MRI is the procedure of choice in the staging of cervical and endometrial cancer.

Endometriosis↗
PubMed1990

Magnetic resonance imaging in the evaluation of infertile women.

Infertility can be due to a variety of causes, ranging from genetic or endocrine disturbances to structural abnormalities. Imaging is often used in the evaluation of anatomic abnormalities. The advent of magnetic resonance imaging (MRI) has greatly improved diagnostic accuracy in the workup of several entities causing infertility. Developmental abnormalities of the reproductive tract are particularly well suited to diagnosis by MRI, which clearly demonstrates the zonal anatomy of the corpus, cervix, and vagina. Correct classification of an anomaly can spare the patient unnecessary laparoscopy or surgery. Leiomyomas, another cause of infertility, are optimally evaluated by MRI, since the size, number, location, and extent of degeneration can be identified. These factors are important in deciding how the leiomyomas will be treated. Adenomyosis can cause uterine enlargement and can be misconstrued as fibroids. MRI is the only noninvasive method that can prospectively diagnose adenomyosis. Ovarian masses can also give rise to infertility. MRI is particularly well suited to clarify whether a mass is uterine or ovarian. It is also much more specific than ultrasound in the differential diagnosis of a mass, especially endometriomas, dermoids, and fibromas. Polycystic ovarian disease, usually diagnosed via hormonal measurements, also has a characteristic appearance on MRI.

Female↗
PubMed1989

Uterine junctional zone: MR study of water content and relaxation properties.

Weighted samples of uterine myometrium, junctional zone, and endometrium were excised for determination of T1 and T2 in a 20-MHz spectrometer and then dried for determination of water content. The remainder of each uterus, examined with special histopathologic stains, demonstrated no significant difference in the number of blood vessels, smooth muscle cells, fibroblasts, elastin, iron, collagen, mucin, polysaccharide, or amyloid. The junctional zone water content (79.28%) was significantly lower than that of endometrium (82.88%, P = .004) and myometrium (81.05%, P = .005). The T1 of the junctional zone (ie, 643) was significantly lower than that of endometrium (ie, 836; P = .004) and myometrium (ie, 709; P = .01). The T2 of the junctional zone (ie, 58) was significantly lower than that of endometrium (ie, 87; P = .003) and myometrium (ie, 67; P = .006). The low signal intensity of the junctional zone on T2-weighted MR images is accounted for by its lower water content and T2, while the brightness on T1-weighted images is due to its reduced T1.

Adult↗
PubMed1989

MR characterization of adrenal masses: field strength and pulse sequence considerations.

The authors evaluated the ability of magnetic resonance (MR) imaging at 1.5 T to characterize 28 adrenal masses, using several variables: signal intensity ratios (adrenal/liver and adrenal/fat) on T2- and T1-weighted images, and the calculated T2 relaxation time of the adrenal mass. Signal intensity ratios were unreliable in distinguishing adenomas from nonadenomas. The calculated T2 relaxation time was more useful: All 15 adrenal masses with a T2 of less than 60 msec were adenomas. A T2 greater than 60 msec was less specific and included six metastases, two pheochromocytomas, one adrenal carcinoma, two adrenal hemorrhages, and two nonhyper-functioning adenomas. Therefore, T2 values are more accurate than signal intensity ratios for characterization of adrenal masses at 1.5 T. The unsuitability of previously published criteria determined with 0.35- and 0.5-T systems may reflect the change of T1 and T2 relaxation times with field strength, altering the relative T1 and T2 weighting by a given pulse sequence.

Adenoma↗
PubMed1989

Endometriosis: appearance and detection at MR imaging.

Thirty-nine magnetic resonance (MR) studies were performed on 31 women with surgically proved endometriosis. A total of 88 endometriotic lesions ranging in size from 0.2 to 7.5 cm were detected on 24 of 30 MR images of women. The signal intensities ranged from hyperintense on all pulse sequences (41 of 88) to hypointense on all sequences (24 of 88); the remainder demonstrated signal intensities corresponding to the appearances of acute, subacute, and chronic hematomas. Hypointense or signal-void rims on both T1- and T2-weighted images were detected in 35 lesions. Identification of the disease with MR imaging versus concurrent surgery was compared for 76 sites in 19 patients. Findings were true-positive in 24 cases, false-negative in ten, true-negative in 32, and false-positive in seven, resulting in an MR sensitivity of 71% and specificity of 82%. Adhesions obscured the disease at laparoscopy in three patients. MR imaging cannot be used as a substitute for laparoscopy in the definitive diagnosis or staging of endometriosis. However, it can be used to monitor treatment response in place of laparoscopy once a diagnosis is firmly established.

Adult↗
PubMed1989

Society of Uroradiology Award paper. The pars infravaginalis gubernaculi: importance in the identification of the undescended testis.

The gubernaculum, a cordlike structure that extends from the testis to the scrotum and guides the testis in its descent, has a bulbous termination, the pars infravaginalis gubernaculi. We reviewed seven surgically proved cases in which the pars infravaginalis gubernaculi was mistaken for an undescended testis on imaging studies. The studies included sonography (five cases), CT (two cases), and MR imaging (two cases). Identification of the mediastinum testis on sonograms or MR images confirms that a structure is testis and not the pars infravaginalis gubernaculi. In two of these patients, testicular venography was used to further identify the undescended testis. In these two patients, the pampiniform plexus, which is used to identify the presence and position of testis, was located adjacent to the pars infravaginalis gubernaculi. Our experience indicates that the pars infravaginalis gubernaculi can be similar in appearance to the undescended testis on any imaging study. The finding of an apparent cord leading to a testislike structure on caudad sectional imaging does not obviate searching for the testis as far as the renal hila.

Adolescent↗
PubMed1988

Nonpalpable testes in young boys: evaluation with MR imaging.

A prospective evaluation of magnetic resonance (MR) imaging for localization of a nonpalpable testis was performed in 24 boys aged 11 months to 6 years. Definitive surgical follow-up was obtained for 15 nonpalpable testes in 14 patients who form the basis of this study. MR imaging correctly indicated the unilateral absence of a testis in six of seven patients prospectively and all seven patients retrospectively. Surgically localized undescended testes were identified with MR imaging in five of eight cases prospectively and seven of eight cases retrospectively. Like scrotal testes, undescended testes were hypointense to fat on sequences with a short repetition time (TR) and echo time (TE) in all cases, and hyperintense or isointense to fat on long TR/TE sequences in all but two cases. Inguinal testes were located along the course of a linear low-signal-intensity structure that extended to the scrotum, which may represent the remnant of the gubernaculum testis. A low-signal-intensity band through the testis, presumably the mediastinum testis, was seen in five of the undescended testes. Although MR imaging can often be used to localize a nonpalpable testis, currently MR is not sensitive enough to allow complete exclusion of the diagnosis of an undescended testis; thus failure to localize a testis with MR imaging should not defer laparoscopy or surgical exploration when indicated.

Child, Preschool↗