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Biomedical subjects

Y Itzchak

Publications and source records attributed to Y Itzchak.

At least 19 recordsLinked to original sources
PubMed1992

Acute severe combined demyelination.

We present a second case in which Guillain-Barré syndrome (GBS) and acute disseminated encephalomyelitis (ADEM) appeared simultaneously, both in acute and fulminant form. The patient, a 10-year-old girl, presented with acute onset of coma and flaccid, are-flexic quadriparesis. The elevated CSF protein levels and delayed F waves fulfilled the criteria of GBS and an MRI study revealed extensive multifocal demyelination compatible with a diagnosis of ADEM. Prompt clinical response followed by complete recovery was achieved by treatment with corticosteroids. It is suggested that acute severe combined demyelination might constitute a separate entity in which the demyelinating process, involving simultaneously the central and the peripheral nervous systems, indicates immune response against a component of the myelin of one system carrying cross-antigenicity with the other.

Acute Disease↗
PubMed1992

Renal pyelectasis in pregnancy: correlative evaluation of fetal and maternal collecting systems.

OBJECTIVE: The current study is aimed at assessing the possibility of a statistical relationship between fetal and maternal collecting system dilatation during pregnancy. STUDY DESIGN: Two hundred thirty consecutive pregnant women and their fetuses (20 to 40 weeks' gestation) were simultaneously examined by ultrasonography. The renal collecting systems were measured, and the frequency of dilatation was subjected to chi 2 analysis. The temporal incidence of fetal pyelectasis was compared with the maternal incidence. RESULTS: Dilatation of maternal collecting systems was detected in 91 of 230 patients (40%) and fetal pyelectasis occurred in 60 of 230 (26%). Fetal pyelectasis was 5.6 times more likely to occur in fetuses of mothers with dilated collecting systems. Furthermore, the temporal incidence of fetal pyelectasis throughout pregnancy appeared similar to that of maternal pyelectasis. CONCLUSION: This study points out the existence of a statistically significant association between maternal and fetal collecting system dilatation during pregnancy.

Chi-Square Distribution↗
PubMed1991

Sciatic nerve: sonographic evaluation and anatomic-pathologic considerations.

Sonographic analysis of the sciatic nerve was performed in vitro (anatomic specimen), in vivo (healthy volunteers), and in 16 patients with suspected peripheral sciatic nerve lesions. The ultrasound (US) examinations were performed with standard and high-resolution US equipment with linear-array configuration. The normal nerve displayed an echogenic fibrillar texture with round cross-sectional structure on both in vitro and in vivo sonograms. Satisfactory delineation of the nerve was obtainable in all cases. Nerve displacement was the main sonographic finding in cases of extrinsic compression. The lesion displayed variable echotexture, ranging from hypoechogenicity or mixed echogenicity in hematomata to hyperechogenicity in cases of fibrosis. Primary nerve tumors (neurofibroma) or infiltrating tumors (desmoid) caused clear disruption of the nerve structure. Use of sonography enabled assessment of the continuity of the nerve margins with the interposed graft in a case of reconstructive surgery. The potential to image sciatic nerve lesions noninvasively may have an important impact on diagnosis, treatment, and prognosis in symptomatic patients.

Adult↗
PubMed1990

Ultrasonic attenuation maps of liver based on a conventional B-scan and an amplitude loss technique.

The authors present a novel ultrasonic amplitude loss technique, using image processing techniques and designed for computation of local attenuation estimates. Three different estimation approaches were evaluated: the extended Prony, the maximum likelihood, and the least squares approaches. The latter two approaches were found to result in a much higher estimation error than that observed for the Prony method. The attenuation values in the normal population (49 subjects) were 0.44 +/- 0.03 dB/MHz/cm. Three hundred sixty-seven liver scans from 266 patients were evaluated. Hodgkin's lymphoma patients with liver involvement had attenuation values of 0.22 +/- 0.07 dB/MHz/cm. Low attenuation values also were observed for four patients with viral hepatitis (0.31 +/- 0.08 dB/MHz/cm). The detectability of other disease states was not increased by these global attenuation estimates; however, the results demonstrate possible potential uses for the proposed technique for the diagnosis of diffuse liver disease.

Adult↗
PubMed1990

High-resolution sonography of the undescended testis in childhood: an analysis of 45 cases.

A prospective study correlating the ultrasound and operative findings was carried out in 45 consecutive pediatric patients with undescended testes. Thirty-six of 37 (97%) palpable testes were located preoperatively by ultrasound. Six of eight impalpable testes (75%) were correctly localized by ultrasound. The three testes missed by the ultrasound examination were found to be atrophic at surgery. Three intra-abdominal (palpable) testes were found at surgery just proximal to the internal ring; all three had been identified by ultrasound preoperatively. The main contribution of ultrasound was the preoperative detection of impalpable testes (six of eight), which modified the consequent surgical approach. Ultrasound also helped in providing objective support to the clinical diagnosis in 36 of 37 children with palpable undescended testes. The ultrasound examination is noninvasive, nonionizing, readily available and of low cost. It is therefore suitable as the initial routine procedure for the evaluation of undescended testis.

Adolescent↗
PubMed1989

Local tissue attenuation images based on pulsed-echo ultrasound scans.

This paper presents a novel technique for creating images of local tissue attenuation. The original conventional B scan is traversed, one pixel at a time. In the vicinity of each pixel, a uniform area is determined and average attenuation is computed utilizing an extended modified Prony approach. B scans of tissue mimicking phantoms and in vivo human liver scans are used in order to illustrate the performance of the proposed algorithm. The results show good agreement between estimated and known attenuation values. Clinical studies demonstrate significant potential of the proposed technique, in particular for diagnosis of diffuse liver disease.

Algorithms↗
PubMed1988

Sonography of the hip joint as part of the evaluation of acute lower abdominal pain.

Ultrasound evaluation of the hip joint was performed in 17 patients as part of the sonographic investigation of lower abdominal pain with referred symptomatology to the groin and thigh. Sonographic features consistent with hip joint effusion were detected in 12 of the patients. In four patients with positive arthrosonogram the possibility of hip joint involvement was not considered by the examining physician. In 11 other cases, hip pathology was included in the differential diagnosis. Of these, hip involvement was confirmed by sonography in eight patients and excluded in three. Sonography was found to be a useful objective method for the confirmation or exclusion of hip joint effusion. The examination had a significant influence on the patient management for shifting the attention of the clinician from the abdomen to the hip joint in four of the cases in this series.

Abdomen↗
PubMed1988

Sonographic detection of occult bone fractures.

Two infants of 24 and 20 months of age with painful local swelling at the femoral and clavicular regions were investigated by ultrasound after a negative radiographic study of the adjacent bones. In both children high resolution ultrasound clearly revealed the presence of bone fractures in addition to the soft tissue hematomas. These fractures were confirmed by a repeat radiographs performed 6 and 8 days later. Although sonography is not the method of choice for the detection of bone fractures, it may be worthwhile to examine the bone contour for a fracture when a painful swelling adjacent to bone is present. The method may be particularly rewarding in children due to its rapid non-invasive nature and to the small tissue thickness that has to be penetrated.

Child, Preschool↗
PubMed1988

Sonographic evaluation of ovarian torsion in childhood and adolescence.

Emergency sonographic examination of the pelvis was performed in 41 girls (mean age, 13 years old) with clinical suspicion of ovarian torsion. Sonographic features consistent with diffuse swelling of the ovarian parenchyma and follicular enlargement in the cortical zone were detected in eight patients and were considered highly suggestive for torsion of the ovary. Surgery revealed ovarian torsion in seven of these cases and hemorrhagic ovarian cyst in one case. A cystic or complex ovarian mass was detected by sonography in five additional cases, and ovarian torsion was included in the differential diagnosis. Surgery revealed ovarian torsion in four of these cases and hemorrhagic ovarian cyst in one. A 100% sonographic sensitivity for space-occupying disease of the ovary was obtained with a positive predictive value of 88% for the diagnosis of ovarian torsion. The specificity of the method was 93%. Sonography appears to be an excellent method to evaluate patients with suspected torsion of the ovary.

Adolescent↗
PubMed1987

Parathyroid sonography: diagnostic accuracy related to shape, location, and texture of the gland.

The sonographic features of 51 pathological parathyroid glands detected pre-operatively were analysed. Atypical texture was found in 23.5% and variation in shape in 15.6% of the cases. Cystic parathyroid glands are difficult to differentiate from thyroid cysts, and may be the cause of false positive diagnosis, as in three cases in this series. Topographic assessment showed a relatively low sensitivity in detecting disease in the right upper gland (50%) and in the upper mediastinum (70%). The decreased accuracy in these regions is probably because of the particular anatomical location of the right upper gland and sonographic limitations in screening the mediastinal region. Awareness by the radiologist and surgeon of the variations in texture and location may influence both diagnosis and intraoperative detection of the abnormal parathyroid gland.

Humans↗
PubMed1987

Sonographic localization of hematomas in hemophilic patients with positive iliopsoas sign.

Sonography was performed on 23 hemophilic patients presenting with positive iliopsoas sign. In 21 of these patients sonography confirmed the presence of hematomas. Comparison of the presumed clinical location and the sonographic location, however, revealed a significant discrepancy. Only seven of 15 hematomas that were clinically suspected to be in the iliopsoas muscle were confirmed by sonography at that location. Of the remaining cases, three were localized in the hip joint, one in the proximal thigh, one in the abdominal wall, and one in the iliac fossa. Hemorrhage was not found in two cases. This study indicates that sonography provides valuable information about the site of hematoma in these patients.

Adult↗
PubMed1986

Ultrasonography in the staging of Hodgkin's disease: lymphangiographic correlation.

The contribution of ultrasonography (US) to the staging of Hodgkin's disease was studied in 45 patients. US findings were compared with lymphangiograms (LAG) performed in the same period. In 93% of the patients there was good correlation between the two examinations. In 7% (three patients) there was a discrepancy: LAG showed retroperitoneal node involvement while with US this was negative. There were no false-positive US examinations. We therefore suggest that US be used as the primary method in the initial evaluation of Hodgkin's disease and LAG be performed only when US is negative.

Hodgkin Disease↗
PubMed1986

Breast tumors: evaluation with P-31 MR spectroscopy.

Differences in the energetics of breast carcinomas and benign breast tumors were monitored by recording their high-energy phosphate concentrations using phosphorus-31 magnetic resonance (MR) spectroscopy. Analysis of the P-31 spectra of biopsy samples from five benign breast tumors and nine breast carcinomas showed that the concentrations of nucleoside triphosphates and phosphomonoesters are consistently higher in the carcinomas than in the benign tumors by an average factor of about three. In addition, the chemical shift differences between the alpha-adenosine triphosphate (alpha-ATP) and beta-ATP signals and between the gamma-ATP and beta-ATP signals were larger by about 0.2 ppm in the carcinomas. These differences result from the lower fraction of magnesium-bound ATP found in the carcinomas under our experimental conditions and reflect a decrease of about two in the concentration of free magnesium ions in the carcinomas relative to that in the benign tumors. Despite the limited number of tumors studied, the results suggest that in vivo P-31 MR spectroscopy may become a reliable method for the diagnosis of breast tumors.

Adult↗
PubMed1986

Renal sonography in American Burkitt lymphoma.

Renal involvement is a common finding at necropsy in patients with American Burkitt lymphoma, but its in vivo sonographic features have received little attention in the literature. Of 29 patients with American Burkitt lymphoma who underwent sonography, 10 were found to have renal involvement. The 10 patients demonstrated a range of abnormalities, notably renomegaly (nine patients), diffuse increase in cortical echogenicity (six), and focal renal masses (three). The focal infiltrations were, unexplicably, hypoechoic in two patients and hyperechoic in one. Hydronephrosis was seen in five patients. One patient had evidence of calcium phosphate renal stones. Response to therapy can be assessed by changes in renal size and cortical echogenicity, as well as disappearance of focal lesions.

Adolescent↗
PubMed1985

Apathetic thyrotoxicosis due to hemorrhage into a hyperfunctioning thyroid nodule after excessive anticoagulation.

Hyperfunctioning thyroid nodule was diagnosed in a 72-year-old woman. When the nodule reached a diameter of 3.5 cm, overt thyrotoxicosis of the apathetic type was precipitated by hemorrhage into the nodule during a period of excessive anticoagulation. All abnormal physical signs and symptoms as well as laboratory findings returned to normal within a month, without any specific treatment. It was possible to follow this process by repeated B-mode sonographic examinations and thyroid scans.

Adenoma↗