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Biomedical subjects

B Gorman

Publications and source records attributed to B Gorman.

At least 19 recordsLinked to original sources
PubMed2006

In situ site-specific specimen preparation for atom probe tomography.

Techniques for the rapid preparation of atom-probe samples extracted directly from a Si wafer are presented and discussed. A systematic mounting process to a standardized microtip array allows approximately 12 samples to be extracted from a near-surface region and mounted for subsequent focused-ion-beam sharpening in a short period of time, about 2h. In addition, site-specific annular mill extraction techniques are demonstrated that allow specific devices or structures to be removed from a Si wafer and analyzed in the atom-probe. The challenges presented by Ga-induced implantation and damage, particularly at a standard ion-beam accelerating voltage of 30 keV, are shown and discussed. A significant reduction in the extent of the damaged regions through the application of a low-energy "clean-up" ion beam is confirmed by atom-probe analysis of the damaged regions. The Ga+ penetration depth into {100} Si at 30 keV is approximately 40 nm. Clean-up with either a 5 or 2 keV beam reduces the depth of damaged Si to approximately 5 nm and <1 nm, respectively. Finally, a NiSi sample was extracted from a Si wafer, mounted to a microtip array, sharpened, cleaned up with a 5 keV beam and analyzed in the atom probe. The current results demonstrate that specific regions of interest can be accessed and preserved throughout the sample-preparation process and that this preparation method leads to high-quality atom probe analysis of such nano-structures.

Journal Article↗
PubMed1998

Chemotherapy-related hepatotoxicity causing imaging findings resembling cirrhosis.

In this article, we describe three women in whom changes in the liver resembling cirrhosis occurred during systemic chemotherapy for metastatic breast carcinoma. All three patients were treated with tamoxifen as part of their chemotherapeutic regimen. Abnormalities of biochemical liver tests were associated with the development of a cirrhosis-like appearance of the liver on computed tomography. In two of the patients, hepatic metastases were proved at biopsy. The third patient had no radiologic evidence of metastatic disease. Chemotherapy for metastatic breast carcinoma may cause striking morphologic changes in the liver that resemble cirrhosis. Of importance, these changes should not be mistaken for the development or progression of liver metastases. Alternatively, because of the changes produced by chemotherapeutic agents, detection of metastases on computed tomography alone may be more difficult. Supplementary magnetic resonance imaging may be helpful in selected cases.

Aged↗
PubMed1996

Hepatic adenomatosis.

This case report describes a 41-year-old woman with hepatic adenomatosis (multiple hepatic adenomas) associated with acute hemorrhage. She had no history of oral contraceptive use or corticosteroid therapy. Ultrasonography showed multiple masses in the right lobe of the liver. The clinical associations and potential complications of hepatocellular adenomas are discussed, and the histologic characteristics are provided. Their typical appearance on computed tomography, ultrasonography, magnetic resonance imaging, and nuclear scintigraphy is described. The differential diagnosis of hepatic adenomatosis and multiple solid liver masses is discussed.

Adenoma, Liver Cell↗
PubMed1995

Imaging of gastrointestinal neuroendocrine tumors.

Gastrointestinal neuroendocrine tumors are rare neoplasms that cause classic clinical syndromes because of the excess secretion of specific gastrointestinal hormones. The two most important tumors clinically are insulinomas and gastrinomas. The clinical management of patients with these disorders usually involves the localization and surgical removal of the responsible tumor. Many radiological techniques can be used for tumor localization, including preoperative and intraoperative ultrasound, endoscopic ultrasound, CT, MRI, radionuclide scanning, angiography, and venous sampling. However, there are conflicting claims as to the relative accuracy of these procedures, and many of these investigations are difficult to justify because of their high cost, degree of invasiveness, or lack of precise anatomic information that is obtained. If surgical resection of a neuroendocrine tumor is planned, intraoperative sonography should always be used to detect occult nonpalpable tumors and to discern the relationship of the tumor to vital adjacent pancreatic ductal anatomy. The choice of preoperative imaging is more controversial, and depends on the clinical problem, local expertise, and availability of imaging techniques. Sonography and contrast-enhanced helical CT are the most commonly used preoperative imaging methods, because of their relatively low cost and widespread availability. Radionuclide scanning with a somatostatin analogue, which is a relatively new procedure, may be valuable in patients with symptoms of tumor recurrence.

Angiography↗
PubMed1992

Continuous quality improvement of Pap smears in an ambulatory care facility.

This article describes how the H. Claude Hudson Comprehensive Health Center (Los Angeles) implemented a continuous quality improvement program to reduce the unacceptably high rate of nonrepresentative Papanicolaou (Pap) smears (those lacking endocervical component). A review of the literature and telephone surveys indicated that the optimal Pap smear technique includes the use of a cervical cytobrush. Several cytobrushes were evaluated and one was chosen to be used facilitywide. Clinicians were given in-services on the proper cervical sampling techniques using the cytobrush. The rate of nonrepresentative Pap smears decreased approximately 12% during a five-month period; this has been attributed to uniform implementation of the cytobrush technique in nonpregnant patients, in-service education, and cooperative teamwork.

Clinical Laboratory Techniques↗
PubMed1988

Localization of pancreatic insulinoma: comparison of pre- and intraoperative US with CT and angiography.

Methods of preoperative radiologic localization of insulinoma were compared in 52 patients, 44 of whom had solitary tumors. Examinations performed in these 44 patients were preoperative ultrasonography (US) in 28, angiography in 26, and computed tomography in 23. Prospective sensitivities were 61%, 54%, and 30%, respectively. Imaging sensitivities were lower for the eight patients with multiple insulinomas. In 28 of the 44 patients, intraoperative US was performed without the examiner being aware of the surgical findings. The sensitivity was 84%. Four insulinomas were not palpable but were visualized sonographically. The combined sensitivity of intraoperative US and surgical palpation for detecting solitary insulinomas was 100%. High-frequency intraoperative US is valuable for detecting occult solitary insulinomas and considerably useful for determining the proximity of insulinomas to the pancreatic and bile ducts.

Adenoma, Islet Cell↗
PubMed1987

Significance of tomographic signs in the diagnosis of bronchial carcinoma.

In a previous study the value of conventional tomography was assessed in the diagnosis of 100 potentially malignant opacities on the chest radiograph. To determine which of the radiological signs were most useful the radiologists reviewed 82 of the original 100 radiographs independently, searching for the presence or absence of 36 signs. The five commonest signs of bronchial carcinoma were a mass, coarse linear shadows contiguous to a mass, unilateral hilar enlargement, linear shadows from mass to periphery, and an irregular margin to a mass. The combination of either two or three of these signs was highly sensitive, 95% and 89% respectively, in detecting carcinoma. The most useful specific signs were lobulation of the mass and cavitation with thick or irregular walls.

Bronchography↗
PubMed1987

Medullary thyroid carcinoma: role of high-resolution US.

Medullary thyroid carcinoma accounts for 10% of thyroid malignancies. Accurate determination of the extent of disease is important because surgery is required for initial treatment and recurrence. High-resolution (10-MHz) ultrasonography (US) of the neck was used to study 15 patients with medullary thyroid carcinoma; nine of the 15 had undergone thyroidectomy but had biochemical evidence of tumor recurrence. Metastatic cervical lymph nodes were detected with US in all 12 patients who had metastatic nodes at surgery, although these nodes were palpable in only four. Punctate bright echogenic foci were seen within some of the nodes in nine of the 12 patients (75%). Similar bright echogenic foci were seen within the primary intrathyroid tumor in five of the six patients who had not yet undergone thyroidectomy (83%). Pathologically, these foci correlated with deposits of calcium surrounded by amyloid, which is characteristic of medullary thyroid carcinoma. US is useful for the detection of nonpalpable recurrence of cervical metastatic lymph nodes, and because it is noninvasive and relatively inexpensive, it should be the first imaging investigation performed after thyroidectomy.

Adult↗
PubMed1986

Benign pancreatic insulinoma: preoperative and intraoperative sonographic localization.

Twenty-nine patients with surgically proved benign pancreatic insulinoma were studied by preoperative or intraoperative sonography. Twenty-five patients had solitary pancreatic tumors; four had multiple tumors. Six of the patients with solitary insulinomas and one of the patients with multiple insulinomas had undergone previous unsuccessful exploration. Preoperative sonography was performed in 24 patients with solitary insulinomas, and 15 (63%) were localized. Intraoperative sonography was performed in 22 patients with solitary insulinomas, and 19 (86%) were visualized without having been previously located by palpation. Four of these visible solitary tumors (18%) were not detected by palpation at surgery. All the solitary insulinomas were detected with the combination of palpation and intraoperative sonography. In each of the six patients with solitary insulinoma who had undergone previous surgery, the tumor was visible with intraoperative sonography, which also demonstrated nonpalpable insulinomas in two of the four patients with multiple tumors. Preoperative real-time sonography is a sensitive, noninvasive, inexpensive method for localization of insulinoma. Intraoperative high-frequency sonography is a highly sensitive method for the detection of insulinoma. Intraoperative sonography is also valuable to determine the relationship of the insulinoma to pancreatic and bile ducts and thereby facilitate safe enucleation.

Adenoma, Islet Cell↗
PubMed1984

Assessment of conventional tomography and fibreoptic bronchoscopy in the diagnosis of potentially malignant chest opacities.

Conventional chest tomography and fibreoptic bronchoscopy were performed in 100 patients with a localised chest abnormality on their chest radiographs who had been referred with a possible diagnosis of bronchial carcinoma. Carcinoma was eventually confirmed in 74 cases and in 26 the lesion proved to be benign. The accuracy of tomography in the overall series was 83%, with a sensitivity of 92% and a specificity of 58%. These figures compare favourably with the results of other imaging techniques used in the diagnosis of bronchial carcinoma. In 50 patients bronchoscopy did not suggest carcinoma and in this group of patients 24 had a carcinoma and 26 a benign lesion. The accuracy of tomography in the bronchoscopy negative patients was 74%, the major source of error being the false positive category. The lesion eventually proved to be benign in 33% of the cases where tomography suggested malignancy, but when the tomograms suggested that the lesion was benign a tumour was found to be present in only 12% of cases.

Aged↗
PubMedDate not supplied

Toward explaining the higher incidence of cigarette smoking among black Americans.

Using the 1987 General Social Survey data, the factors related to the disproportionately higher rates of cigarette smoking by Black Americans were investigated. Previous studies have found smoking to be highly correlated with age, social class, and occupational stress, among other factors. It is uncertain whether race is an independent predictor of smoking rates or whether it is primarily a correlate of other demographic variables. Loglinear modeling and logit regression analysis suggested that racial differences between Blacks and Whites in smoking may be spurious. The multivariate analysis established that class and stress differences remained more potent than race in accounting for variations in smoking behavior.

Adolescent↗
PubMedDate not supplied

Focal intracavitary masses recognized with the hyperechoic line sign at endovaginal US and characterized with hysterosonography.

In 42 women, endovaginal ultrasonography (US) was performed because of an abnormal central endometrial complex. Retrospective review of the endovaginal US scans and subsequently obtained hysterosonograms with histopathologic correlation showed a hyperechoic line surrounding the central endometrial complex in 25 patients, all of whom had focal intracavitary processes. Cystic spaces within the central endometrial complex in 17 of these patients reflected polyps; this finding was associated with a hyperechoic line in 15. At hysterosonography, all polyps (n = 29) had a narrow attachment to the endometrium. All five fibroids were broadly attached and had a rim of overlying endometrium. These focal abnormalities were easily distinguished from global endometrial processes amenable to a blind biopsy procedure. This initial experience showed that a hyperechoic line circumscribing the central endometrial complex at endovaginal US allows prediction of focal intracavitary disease, particularly when the line is associated with cystic spaces within the central endometrial complex. The presence of a hyperechoic line can be used to direct the patient to a visually guided hysteroscopic procedure rather than a potentially unsuccessful blind biopsy procedure. Alternatively, absence of a hyperechoic line can prompt management appropriately directed by hysterosonographic characterization of the uterine contents as focal or diffuse.

Algorithms↗
PubMedDate not supplied

Comparison of tissue harmonic imaging with conventional US in abdominal disease.

Harmonic waves are generated from nonlinear distortion of an acoustic signal as an ultrasound wave insonates tissues in the body. These beams are integer multiples of a fundamental transmitted frequency. Potential advantages of harmonic imaging include improved axial resolution due to higher frequencies and better lateral resolution due to narrower beams. Decreased noise from side lobes improves signal-to-noise ratios and reduces artifacts. Deleterious effects of the body wall are also reduced. The authors prospectively studied ultrasonographic (US) findings in 100 adult patients with 202 abdominal lesions by comparing harmonic US images with conventional US images. The results were subjected to statistical analysis. Harmonic imaging was superior to conventional US in regard to lesion visibility and diagnostic confidence. Harmonic imaging was particularly useful for depicting cystic lesions and those containing echogenic tissues such as fat, calcium, or air. In patients with a body mass index of 30 or more, harmonic imaging was clearly better for lesion visibility and confidence of diagnosis. The authors recommend routine use of harmonic imaging for abdominal US studies in all adult patients.

Abdomen↗