Radionuclide imaging of hepatic and biliary disease.

This article will focus on common clinical applications of scintigraphy in focal hepatic lesions, acute cholecystitis, biliary dyskinesia, biliary obstruction, postoperative liver and biliary tract, and neonatal cholestasis. The utility of positron emission tomography will also be addressed.

Comparison of full-field digital mammography with screen-film mammography for cancer detection: results of 4,945 paired examinations.

PURPOSE: To prospectively compare full-field digital mammography (FFDM) with screen-film mammography (SFM) for cancer detection in a screening population. MATERIALS AND METHODS: At two institutions, 4,945 FFDM examinations were performed in women aged 40 years and older presenting for SFM. Two views of each breast were acquired with each modality. SFM and FFDM images were interpreted independently. Findings detected with either SFM or FFDM were evaluated with additional imaging and, if warranted, biopsy. RESULTS: Patients in the study underwent 152 biopsies, which resulted in the diagnosis of 35 breast cancers. Twenty-two cancers were detected with SFM and 21 with FFDM. Four were interval cancers that became palpable within 1 year of screening and were considered false-negative findings with both modalities. The difference in cancer detection rate was not significant. FFDM had a significantly lower recall rate (11.5%; 568 of 4,945) than SFM (13.8%; 685 of 4,945) (P <.001, McNemar chi(2) model; P <.03, generalized estimating equations model). The positive biopsy rate for findings detected with FFDM (30%; 21 of 69) was higher than that for findings detected with SFM (19%; 22 of 114), but this difference was not significant. CONCLUSION: No difference in cancer detection rate has yet been observed between FFDM and SFM. FFDM has so far led to fewer recalls than SFM.

Association of mammographically defined percent breast density with epidemiologic risk factors for breast cancer (United States).

OBJECTIVE: Mammographically defined percent breast density is an important risk factor for breast cancer, but the epidemiology of this trait is poorly understood. Although several studies have investigated the associations between reproductive factors and density, few data are available on the associations of breast density and waist-to-hip ratio (WHR), physical activity, education, alcohol and smoking. METHODS: We investigated the associations of known and suspected breast cancer risk factors with breast density in a large breast cancer family study. Information was collected on members of 426 families through telephone interviews, mailed questionnaires and mammography. Mammographic films on 1900 women were digitized and breast density was estimated in discrete five-unit increments by one radiologist. Analysis of covariance techniques were used and all analyses were performed stratified by menopausal status. RESULTS: Similar to other reports, nulliparity, late age at first birth, younger age and lower body mass index were associated with increased percent density in both premenopausal and postmenopausal women, and hormone replacement therapy among postmenopausal women. Higher levels of alcohol consumption and low WHR were associated with increased percent density among both premenopausal and postmenopausal women (differences of 3-11% between high and low categories). However, smoking and education were inversely associated with percent density among premenopausal (p = 0.004 and p = 0.003, respectively) but not postmenopausal women (p = 0.52 and p = 0.90). Physical activity was not associated with percent density in either stratum (p values > 0.25). Combined, these factors explained approximately 37% of the variability in the percent density measure in premenopausal women and 19% in postmenopausal women. CONCLUSIONS: Many of these factors may potentially affect breast cancer risk through their effect on percent breast density.

Association of diet and mammographic breast density in the Minnesota breast cancer family cohort.

Mammographic breast density is a significant risk factor for breast cancer. The present report analyzes the association of breast density and dietary factors in 1508 women in a historical cohort study of breast cancer families in Minnesota. Diet was assessed by a semiquantitative food frequency questionnaire. Percent breast density was estimated visually by a radiologist experienced in mammography. The association of percent breast density with quartiles of energy-adjusted dietary intakes was examined in analysis of covariance models adjusting for potential confounding effects of age, body mass index, and other covariates as well as correcting for familial correlation. Analyses were performed on all women combined and were also stratified by menopausal status. Among premenopausal women, percent breast density was positively associated with intakes of polyunsaturated fat, polyunsaturated:saturated fat ratio, and vitamins C and E and was inversely associated with saturated fat and total dairy intake. Among postmenopausal women, vitamin B12 was linearly associated with increased breast density. The positive associations for vitamin C and B12 were attributable to supplement intake only. There was a suggestive positive trend between breast density and daily alcohol consumption in both premenopausal and postmenopausal women. After adjustment for other sources of alcohol, only wine intake among postmenopausal women was significant such that white wine showed a positive association and red wine an inverse association with percent breast density. There was no association with other examined dietary factors. The cross-sectional differences in breast density across levels of dietary factors were small in magnitude but may have implications for breast cancer risk.

Genetic analysis of mammographic breast density in adult women: evidence of a gene effect.

BACKGROUND: The appearance of the female breast viewed by mammography varies considerably from one individual to another because of underlying differences in the relative proportions of fat, connective tissue, and glandular epithelium that combine to create a characteristic pattern of breast density. An association between mammographic patterns and family history of breast cancer has previously been reported. However, this association has not been found in all studies, and few data are available on possible genetic components contributing to mammographic breast density. PURPOSE: Our purpose was to estimate familial correlations and perform complex genetic segregation analyses to test the hypothesis that the transmission of a major gene influences mammographic breast density. METHODS: As part of a cohort study (initiated in 1944) of families with a history of breast cancer, the probands' female relatives who were older than 40 years were asked to obtain a routine mammogram. The mammograms of 1370 women from 258 independent families were analyzed. The fraction of the breast volume occupied by radiographically dense tissue was estimated visually from video displays of left or right mediolateral oblique views by one radiologist experienced in mammography who had no knowledge of individual relationships to the probands. Data on breast cancer risk factors were obtained through telephone interviews and mailed questionnaires. Unadjusted and adjusted familial correlations in breast density were calculated, and complex genetic segregation analyses were performed. RESULTS: Sister-sister correlations in breast density (unadjusted and adjusted for age and either body mass index, menopausal status, hormone replacement therapy, waist-to-hip ratio, number of live births, alcohol consumption, or cigarette smoking status) were all statistically significant (r = .16-.27; all P<.05 [two-sided]). Estimated mother-daughter correlations were smaller in magnitude (r = .01-.17) and not statistically significant. Segregation analyses indicate that a major autosomal gene influences breast density. The mendelian transmission of a dominant gene provided the best fit to the data; however, hypotheses involving the inheritance of either a recessive gene or a codominant gene could not be ruled out. The mendelian dominant hypothesis, accounting for 29% of the variability in breast density, suggests that approximately 12% of the population would be expected to carry at least one variant allele of this putative gene. Women who inherit the variant allele would have a mean breast density about twice that of the rest of the population. CONCLUSIONS: Our preliminary findings suggest that, in this cohort of women at risk of breast cancer, mammographic breast density may be genetically influenced.

Regional alterations in lung ventilation in end-stage primary pulmonary hypertension: correlation between CT and scintigraphy.

OBJECTIVE: The purpose of this study was to correlate scintigraphic findings of regional alterations in lung ventilation and perfusion with regional variations in CT attenuation in patients with primary pulmonary hypertension. SUBJECTS AND METHODS: Chest CT scans and ventilation-perfusion scans obtained within 24 hr of each other in 18 patients with primary pulmonary hypertension referred for lung transplantation were reviewed. The lungs were divided into eight regions (left/right, superior/inferior relative to the carina, and anterior/posterior relative to the trachea). CT scans were evaluated and areas of parenchymal inhomogeneities were tabulated for the eight regions. Areas of reverse mismatch (perfusion without ventilation) were established by blinded analysis of planar scintigraphic studies in six projections using 99mTc-labeled DTPA-aerosol and macroaggregated albumin for the eight regions and then were correlated with the CT findings. RESULTS: Abnormal findings on ventilation scans and reverse ventilation-perfusion mismatches indicating an inadequate hypoxic vasoconstriction reflex were found in 91 regions in all 18 patients. Nonuniform parenchymal CT density was found in 12 patients. There was a significant correlation (p = .009) of scintigraphic reverse mismatches with abnormal CT density in 38 regions in 11 patients. In one patient, there was no scintigraphic correlation with abnormal CT attenuation. The specificity of abnormal CT density for scintigraphic reverse mismatches was 81%, with a sensitivity of 42%. CONCLUSION: Scintigraphic reverse mismatches indicate a high prevalence of significant pulmonary arterial shunting in patients with ventilatory defects. Increased relative CT attenuation in areas of impaired ventilation as shown on the ventilation scans is amplified in primary pulmonary hypertension by an inadequate hypoxic vasoconstriction reflex. This finding does not signify underlying infiltrative lung disease and correlates with regions with reverse mismatches.

Epidemiologic and genetic follow-up study of 544 Minnesota breast cancer families: design and methods.

In 1944, a case-control family study was initiated at the Dight Institute for Human Genetics at the University of Minnesota to study the influences of childbearing breastfeeding, and hereditary susceptibility on the occurrence and age-of-onset of breast cancer. Index cases (probands) were women ascertained at the Tumor Clinic of the University of Minnesota Hospital. Medical history and life style information were obtained on probands and relatives, and all cancers were histologically verified. A total of 544 families were studied, with probands diagnosed between 1931 and 1952. All of the records and pathology slides have been maintained from the original study; for most probands this includes the original tissue blocks. We are conducting a historical cohort study of selected of selected first- and second-degree female relatives (sisters, daughters, nieces, granddaughters) of the probands and a group of control women identified as the spouses of all male first- and second-degree relatives (brothers, sons, grandsons, and nephews). The subsequent development of breast cancer is being determined to quantify the absolute risk associated with a positive family history. Current disease status is ascertained with mammography, and stromal density is measured using digital imaging. Segregation analysis will be applied to examine how non-genetic factors such as diet, exogenous hormone use, and body fat distribution influence risk in women at high risk because of family history. A subset of families are being selected for molecular analysis of the BRCA1 gene or for linkage analyses to identify putative susceptibility loci other than BRCA1. Documented cancer histories were known for at least three generations, and the current study extends the pedigrees up to four or five generations for every family, allowing a detailed description of familial risk. This cohort study of breast cancer families is likely to be important in both quantity and quality of data and will serve as a major genetic epidemiologic resource, being free of selection bias and having relevant non-genetic exposure determined in at least four generations.

Resting Tl-201 scintigraphy in the evaluation of coronary artery disease in children with Hurler syndrome.

Severe coronary artery disease may occur early in the course of mucopolysaccharidosis. The authors present radiologic, scintigraphic, and pathologic findings in five patients with Hurler syndrome. Thallium-201 myocardial scintigraphy and selective coronary angiography obtained within 2 days to 6 months were correlated in five patients. Postmortem examination of the coronary arteries was obtained in one patient within hours of angiography. Interobserver agreement on grading of scintigraphic abnormalities was poor. Nonspecific findings on Tl-201 studies included septal abnormalities in all five patients. Scintigraphic findings were corroborated by angiography and postmortem results in only 3 of 5 patients. Our findings suggest that resting Tl-201 scintigraphy has limited value in the detection of coronary artery disease in patients with Hurler syndrome.

Role of radiology in medical education: perspective of nonradiologists.

RATIONALE AND OBJECTIVES: We asked our nonradiologist colleagues to evaluate and comment on the most desirable format for radiology education. METHODS: Questionnaires were distributed to 631 nonradiologist physicians affiliated with the University of Minnesota and representing all medical specialties and academic ranks. Three hundred twenty-seven surveys were returned after one mailing. RESULTS: Residency was retrospectively noted to be indispensable for consolidating knowledge of radiology. The overwhelming majority of clinicians in all specialties believed that formal radiologic instruction should be mandatory for medical students (279 of 322; 87%). Film interpretation was believed to be an indispensable part of a medical student radiology rotation (226 of 321; 70%), but many clinicians indicated a need for additional training. A marked disparity in the perceived level of confidence in interpreting radiologic tests during medical school and residency between those who had and those who had not received formal radiologic instruction during medical school was evident. This difference in perceived level of confidence was present even among the most experienced clinicians. CONCLUSIONS: Collectively, the nonradiologist clinicians emphasized the need for a mandatory and clinically oriented radiology curriculum during medical school.

A comparison of single blood sample and multiple blood sample methods to measure GFR in a pediatric population.

Several single-sample, Cr-51 EDTA based methods of estimating glomerular filtration rate in children have been proposed. The authors retrospectively reviewed our experience in 467 pediatric patients using Tc-99m DTPA and 4 ultrafiltered serum samples drawn 2-4 hours postinjection. The authors used the 2-hour specimens for the single-sample method. Regression analysis of the 2 techniques revealed significant scatter. Mathematically, it was shown that the error of the single-sample method was minimized when the clearance t 1/2 equalled the sampling time x 0.693. This model predicted a 300% error when the t 1/2 was varied to its observed extremes. The observed error of the single-sample method fit this theoretical prediction very well. Analysis of a two-sample method versus the four-sample method showed no improvement in results. In a subset of 18 unfiltered plasma samples, the glomerular filtration rate was falsely low in 12 patients. The authors conclude that multiple blood samples and serum ultrafiltration are required to accurately measure glomerular filtration rate when using Tc-99m DTPA.

Postoperative diuresis renography and ultrasound in patients undergoing pyeloplasty. Predictors of surgical outcome.

The authors reviewed 50 pediatric patients (56 renal units) who underwent pyeloplasty and had serial preoperative and postoperative diuresis renogram and ultrasound studies. Of those patients that clinically improved with surgery, 73% and 91% showed improved renographic patterns in postoperative studies at 3 and 12 months, respectively. Ultrasound demonstrated more gradual improvement in grade and pelvic diameters over longer study intervals. Diuresis renography is an excellent predictor of surgical outcome within 3 months of pyeloplasty and showed change well in advance of that seen on ultrasound. Sonography is better suited to longer term evaluation of grade, pelvic diameter, and renal size.

Mammography in the 1990s: a plea for objective doctors and informed patients.

Mammography screening is increasingly promoted as a means to avoid death from breast cancer. Although some randomized trials have shown a mortality benefit in the older screened groups, not all the results have been statistically significant; benefit has not been shown in younger age groups. Mammography detects smaller lesions than physical examination, but the only randomized trial comparing the mortality benefits of mammography and physical examination shows no benefit for mammography. The systemic nature of breast cancer raises questions about the theoretical mortality benefit of screening. Patients undergoing mammography may experience unexpected anxiety about the results. Candidates for screening should be routinely informed of these issues.

Reverse mismatch between perfusion and aerosol ventilation in transplanted lungs.

Thirty ventilation-perfusion pulmonary scintigraphic studies were performed in 13 patients who had undergone unilateral lung transplantation. Ventilation-perfusion mismatch (ventilation better than perfusion) was judged absent, mild, moderate, or severe in the transplanted and native lungs. Ventilation-perfusion mismatch was significantly worse in the transplanted lungs (p < .0001). Findings of lung biopsies and chest roentgenograms failed to correlate with the severity of ventilation-perfusion mismatch. Hypoxic pulmonary vasoconstriction appears to be significantly impaired in most unilateral lung transplants; the mechanism for this impairment is unclear.

Comparison of Tc-99m DTPA aerosol ventilation studies with pulmonary function testing in cystic fibrosis.

In 43 patients with cystic fibrosis, the results of 122 Tc-99m DTPA aerosol ventilation (DAV) studies were compared with pulmonary function tests (PFTs) that were performed within 24 hours of the DAV studies. The DAV studies were evaluated blindly for (A) number of pulmonary segments showing little or no ventilation, (B) number of foci of bronchial deposition of aerosol, and (C) subjective overall improvement, lack of change, or worsening from the previous study. (A) and (B) correlated significantly with all PFTs (p's < .001, r's = -.51 to -.73). Changes in (A) and (B) also correlated with changes in PFTs (p's < or = .001, r's = -.37 to -.58). The three populations in (C) were significantly different from each other with respect to changes in all PFTs (p < or = .002). Intervals between studies showing subjective improvement, no change, and worsening averaged 60, 133, and 306 days, respectively. These results suggest that DAV is an indicator of both regional and global pulmonary function and may be useful in evaluating patients with cystic fibrosis.

Aerosol scintigraphy in the assessment of therapy for cystic fibrosis.

Thirteen patients with cystic fibrosis (aged 11 to 32 years) who were hospitalized for exacerbation and who had sputum cultures positive for Pseudomonas organisms were treated initially for 4 days with bronchodilators and physiotherapy followed by the addition of antibiotic (14 days, n = 8) or placebo (14 days, n = 4; 7 days, n = 1). Tc-99m DTPA aerosol scintigraphy was performed on the day before bronchodilators and physiotherapy, on the day before antibiotic or placebo, and on the day after completion of antibiotic or placebo therapy. Scintigrams were evaluated for change in the number of nonventilated segments and change in the number of bronchial deposits of aerosol. Sixty-nine percent of patients showed improvement after bronchodilators and physiotherapy alone. Sixty-two percent showed further improvement after antibiotic or placebo was added; this improvement was independent of whether antibiotic or placebo was administered (P greater than 0.1). These aerosol scintigraphy results failed to demonstrate that the effectiveness of bronchodilators and physiotherapy is enhanced by antibiotics in the treatment of cystic fibrosis exacerbations.