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Biomedical subjects

J H MacGregor

Publications and source records attributed to J H MacGregor.

14 recordsLinked to original sources
PubMed2001

Diagnostic accuracy of a stereotaxically guided vacuum-assisted large-core breast biopsy program in Canada.

OBJECTIVE: To assess the accuracy rate associated with 11-gauge vacuum assisted large-core breast biopsy (VALCBB) at our institution. METHODS: 673 consecutive VALCBBs performed between September 1997 and March 2000 were evaluated. For most of the benign VALCBB specimens, accuracy was determined by the stability of the lesions on follow-up mammography. When possible, histological results of specimens obtained from VALCBB and of specimens obtained from surgical excision were compared. Modified accuracy rates were calculated. RESULTS: Of the 673 biopsies, 499 (74%) were benign; for the 315 benign lesions for which complete follow-up information was available, a greater than 99% modified accuracy rate was obtained. The modified accuracy rate for the 174 nonbenign lesions was 95%. Thus, VALCBB yielded an overall modified accuracy for both benign and nonbenign lesions of 97.9%. CONCLUSION: VALCBB provides accurate histological results for biopsy of suspicious lesions of the breast.

Biopsy↗
PubMed2000

Vacuum-assisted large-core breast biopsy: complications and their incidence.

OBJECTIVE: To assess both the rate and types of complications associated with vacuum-assisted large-core breast biopsy (VALCBB) at our institution. METHODS: Three hundred and four VALCBBs performed in 297 patients between Sept. 18, 1997, and Mar. 30, 1999, were evaluated. Complications associated with VALCBB were assessed at the time of the procedure and in the post-procedure period. Adverse outcomes included pain, bleeding or bruising, and hematoma. Complications were also classified in terms of minor, significant, and major severity. RESULTS: VALCBB yielded non-minor (i.e., significant and major) complication rates of 3.9% during the procedure and 3.6% in the post-procedure period, with only 2 complications (vasovagal-induced seizure and migraine) that required treatment. CONCLUSION: With proper technique and patient preparation, VALCBB is a very safe procedure with a low complication rate.

Adult↗
PubMed1995

Regional left ventricular systolic function in relation to the cavity geometry in patients with chronic right ventricular pressure overload. A three-dimensional tagged magnetic resonance imaging study.

BACKGROUND: Distortion of the left ventricular (LV) cavity in patients with right ventricular pressure overload (RVPO) is well known. However, no direct measurements of regional myocardial function in terms of myocardial shortening and wall thickening are available; therefore, exactly how RVPO disturbs LV regional performance remains unclear. By using three-dimensional (3D) tagged magnetic resonance imaging, we were able to measure regional systolic function directly. Our objective was to study the relation between the distortion of the LV circular shape and regional LV function. METHODS AND RESULTS: In nine patients with RVPO and six healthy volunteers, four parallel short-axis images (with 12 radial tags) and two mutually orthogonal long-axis images (with four parallel tags) were generated, and endocardial and epicardial borders were manually traced. By integration of the short- and long-axis images, 3D reconstruction of the LV tracking points from end diastole to end systole was obtained. Data from the midventricular two short-axis image slices were analyzed. These were then divided into anterior, lateral, posterior, and septal regions. Circumferential and longitudinal shortening were then calculated from the endocardial and epicardial tag intersection points. Wall thickness and thickening were calculated by the 3D volume-element approach. An eccentricity index (EI), the ratio of septum-to-free-wall to anteroposterior diameters, was used to describe the shape of the LV cavity. The regional curvature was also measured. The RVPO group was characterized by flattening of the septum and LV lateral wall, decreased EI reflecting the distorted LV shape, altered distribution of endocardial circumferential shortening, and preserved ejection fraction. Changes in EI closely correlated with the septal curvature. The EI was smaller at end systole, reflecting further shape distortion relative to end diastole. Reduced myocardial performance, as measured by wall thickening and circumferential and longitudinal shortening fractions, was observed for the septum. A reduction in endocardial circumferential shortening of the septal and lateral walls was directly related to the end-systolic EI. In addition, whereas for healthy subjects a linear relation between area ejection fraction and endocardial circumferential shortening was observed, in RVPO patients a curvilinear (quadratic) relation was observed. CONCLUSIONS: In patients with RVPO, compared with healthy subjects, the septal function was reduced, as evidenced by reduced thickening and shortening fractions. The distortion in LV cavity at end systole due to the flattening of the septum contributes to preserved systolic ventricular function and nonuniform distribution in endocardial circumferential shortening.

Adult↗
PubMed1994

Temporal contour deformity after coronal flap elevation: an anatomical study.

Temporal contour deformity is defined as a concavity or depression in the temporal region located superior to the zygomatic arch and immediately posterior to the lateral orbital rim. The deformity can present as a consequence of extended coronal flap elevation for exposure of the lateral craniofacial skeleton. This study describes the anatomical and pathological features of the deformity and identifies causative factors. The series consists of unilateral temporal contour deformities after coronal flap elevation in 6 patients. A standardized data sheet was used in documenting details of the initial temporal dissection, clinical findings, and radiological features. Elevation of the temporal soft tissues was based on a qualitative analysis of coronal magnetic resonance imaging (MRI) scans comparing the affected and the unaffected temporal regions. The MRI studies demonstrated normal volume of the temporalis muscle in all cases, with no evidence of atrophy or disinsertion of the muscle. Diminution in the volume of the superficial temporal fat pad was identified in 4 patients, whereas inferior displacement or prolapse of the superficial temporal fat pad was noted in 2 patients.

Adipose Tissue↗
PubMed1994

Left ventricular wall thickness and regional systolic function in patients with hypertrophic cardiomyopathy. A three-dimensional tagged magnetic resonance imaging study.

BACKGROUND: Regional performance of the hypertrophied left ventricle (LV) in hypertrophic cardiomyopathy (HCM) is still incompletely characterized with studies variably reporting that the hypertrophied myocardium is hypokinetic, akinetic, or has normal function. Different imaging modalities (M-mode or two-dimensional echocardiography) and methods of analysis (fixed or floating frame of reference for wall motion analysis) yield different results. We assessed regional function in terms of systolic wall thickening and shortening and related these parameters to end-diastolic thickness using tagged magnetic resonance imaging and the three-dimensional volume-element approach. METHODS AND RESULTS: In 17 patients with HCM and 6 healthy volunteers, four parallel short-axis images with 12 radial tags and two mutually orthogonal long-axis images with four parallel tags were obtained at end diastole and end systole. After the LV endocardial and epicardial borders were traced, three-dimensional volume elements were constructed by connecting two matched planar segments in two adjacent short-axis image planes, accounting for translation, twist, and long-axis shortening. A total of 72 such volume elements encompassed the entire LV. From each of these elements, end-diastolic thickness and systolic function (fractional thickening and circumferential shortening) were calculated. The average end-diastolic thickness was 15.8 +/- 4.2 mm in patients with HCM, which was significantly greater than that in healthy subjects (8.6 +/- 2.1 mm, P < .001). Fractional thickening was significantly less in patients with HCM than in healthy subjects (0.31 +/- 0.22 versus 0.56 +/- 0.23, P < .001). There was a highly significant inverse correlation between fractional thickening and end-diastolic thickness that was independent of the type of hypertrophy or age group. Similar inverse relations were observed between circumferential shortening and end-diastolic wall thickness. CONCLUSIONS: The myocardium in patients with HCM is heterogeneously thickened and the fractional thickening and circumferential shortening of the abnormally thickened myocardium are reduced compared with healthy subjects. The decrease in fractional thickening and shortening is inversely related to the local thickness.

Adult↗
PubMed1994

Stereotactic fine-needle aspiration cytology of nonpalpable breast lesions: initial experience in a tertiary-care institution.

To assess the accuracy of stereotactic fine-needle aspiration cytology in the diagnosis of nonpalpable breast lesions, this procedure was performed in 226 consecutive patients, all women, immediately before needle localization and excision of the lesions. The patients were treated at a tertiary-care hospital between December 1989 and October 1991. The cytologic results (lesion benign, atypical, suspicious or malignant or insufficient material for interpretation) were compared with the histologic findings and the degree of suspicion (low, slight or high) on the basis of mammographic examination. The aspiration procedures were successful in only 159 patients (70.4%), and for 155 of these, histologic findings were available for correlation. The number of unsatisfactory specimens in this group was large: 65 of 155 (42%). When unsatisfactory specimens were included in the calculations and a cytologic finding of a suspicious or malignant lesion was treated as positive, the sensitivity of fine-needle aspiration cytology for malignancy was 23% (8/35) and the specificity 53% (63/120). The positive and negative predictive values were 89% (8/9) and 78% (63/81) respectively. A cytologic finding that the lesion was benign was unreliable in lesions for which the mammographic suspicion of malignancy was slight or high (4 of 30 malignant lesions with slight mammographic suspicion and 4 of 7 with high mammographic suspicion were classified as benign on the basis of the cytologic examination). Of the 24 cases with atypical cytologic findings, 10 involved malignancy.(ABSTRACT TRUNCATED AT 250 WORDS)

Biopsy, Needle↗
PubMed1991

Hepatic artery pseudoaneurysms in acute pancreatitis.

The authors present a case of multiple intrahepatic pseudoaneurysms complicating acute gallstone pancreatitis, and they review the relevant literature. The complementary roles of ultrasonography, computed tomography and arteriography are illustrated. Although necrotizing vasculitis with resultant aneurysmal changes in peripancreatic vessels is a recognized complication of chronic pancreatitis, similar pseudoaneurysms have rarely been described in association with acute pancreatitis.

Acute Disease↗
PubMed1989

Variations in fluoroscopic and spot film techniques during extracorporeal shock wave lithotripsy.

The radiation techniques of different operators who performed extracorporeal shock wave lithotripsy of the kidney were evaluated retrospectively. The study was limited to 9 operators who each performed more than 100 procedures on the Dornier lithotriptor. The average fluoroscopic time and number of video spot films per procedure for all operators were 4.1 minutes and 6.5, respectively. However, the average fluoroscopic time per operator varied from 1.4 to 7.6 minutes and the average number of video spot films per operator varied from 3 to 13. The results illustrate the need for some operators to reduce fluoroscopic time and video spot filming.

Fluoroscopy↗
PubMed1989

Delayed sequelae of pulmonary barotrauma.

Progression of cystic changes in the lung, with development of pneumothoraces long after withdrawal of ventilatory support, was observed in two patients who recovered from adult respiratory distress syndrome. On pathologic examination both pleural and parenchymal cysts were confirmed.

Adult↗
PubMed1987

The radiographic distinction between pericardial and myocardial calcifications.

Calcification overlying the left side of the heart on a chest radiograph may involve either the pericardium or, alternatively, the myocardium in association with a left ventricular aneurysm. Distinction between these two conditions can be of great clinical significance. To identify distinguishing features, we reviewed the radiographs and medical records of 29 patients: 14 had proven calcific pericarditis and 15 had proven calcified left ventricular aneurysm. Pericardial calcification was found primarily over the right-sided cardiac chambers (14 of 14 patients) and in the atrioventricular grooves (11 of 14), infrequently over the base of the left ventricle (five of 14), and rarely over the apex of the left ventricle (two of 14). When the left ventricle was involved, there was always more extensive calcification elsewhere in the pericardium. Myocardial calcification occurred predominantly in the apex of the left ventricle (13 of 15 patients), although it was rarely confined to the posterior wall of the left ventricle (two of 15). By noting characteristic sites of calcium deposition, pericardial calcification can be effectively distinguished from myocardial calcification. Isolated calcification in the region of the left ventricular apex, therefore, strongly suggests left ventricular aneurysm.

Adolescent↗
PubMed1986

Opportunistic lung infection caused by Rhodococcus (Corynebacterium) equi.

Rhodococcus (formerly Corynebacterium) equi, a common animal pathogen, can cause a slowly evolving pneumonia in humans, particularly immunocompromised people. The authors describe two patients; one with acquired immunodeficiency syndrome. On chest radiographs, R. equi produces chronic, localized pulmonary opacities that can cavitate. The main differential diagnoses are tuberculosis and fungal infection.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Imaging of the axillary subsegment of the right upper lobe.

The bronchial supply of the lateral or axillary area of the right upper lobe is variable. In 16 percent of normal subjects, an independent ramus of the posterior right upper lobe bronchus supplies an axillary subsegment. Airspace disease in the axillary subsegment has a characteristic appearance on radiographs. The CT appearance of disease in the axillary subsegment correlates closely with classic anatomic studies. Recognizing that disease is located in the axillary subsegment can help in directing bronchoscopy or biopsy.

Bronchial Diseases↗