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OBJECTIVE: The objectives of this study were to describe head computed tomography (CT) technical factors used in the United States; assess guideline compliance and variability by sex, geographic region, institution, and manufacturer; and compare with NEXT (Nationwide Evaluation of X-ray Trends) survey. METHODS: Two thousand thirty-five head CT studies from 895 sites were analyzed. Peak kilovoltage, exposure, slice and image number, slice thickness, field of view, interslice gap, reformations, examination inclusiveness, use of contrast, and reconstruction filter were compared by sex, geographic region, institution type, and manufacturer. RESULTS: One hundred twenty to 140 kVp (peak kilovoltage) was used by 99.8% of the sites. There was no correlation between mAs and kVp. There was a 30-fold increase in number of images and nearly 9-fold increase in number of slices from least to most. Nearly 4% use slice thickness and interslice gap greater than guidelines. There were significant regional differences in field of view, image number, and slice thickness. Some variation related to manufacturers was found. Minor difference was also found between academic and nonacademic institutions. There were significant differences in kVp and mAs compared with NEXT. CONCLUSIONS: Significant variations in head CT technique exist in the United States.
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Encefalopatías/diagnóstico por imagen , Encefalopatías/epidemiología , Adhesión a Directriz/estadística & datos numéricos , Cabeza/diagnóstico por imagen , Pautas de la Práctica en Medicina/estadística & datos numéricos , Tomografía Computarizada por Rayos X/estadística & datos numéricos , Tomografía Computarizada por Rayos X/normas , Femenino , Humanos , Masculino , Persona de Mediana Edad , Guías de Práctica Clínica como Asunto , Prevalencia , Dosis de Radiación , Distribución por Sexo , Estados Unidos/epidemiologíaRESUMEN
OBJECTIVE: The objective of this paper was to describe the computed tomographic appearance, characteristics, and significance of fat in the wall of the urinary bladder. METHODS: Twenty-three cases of intramural fat were reviewed. Use of intravenous contrast, sex, and degree of bladder distention were noted. Location of intravesical fat was tabulated. RESULTS: Intramural fat is typically seen as a thin low-density band along the anterior and superior portions of a partially filled urinary bladder. Most of the cases are in men (90%) and are seen on unenhanced studies (>80%). The prevalence of intramural fat was just less than 2%. CONCLUSIONS: Fat within the wall of the urinary bladder can be a normal histological finding that is detected at computed tomography typically in patients with nondistended urinary bladders on unenhanced studies.
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Grasa Intraabdominal/diagnóstico por imagen , Vejiga Urinaria/diagnóstico por imagen , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Persona de Mediana Edad , Valores de Referencia , Tomografía Computarizada por Rayos XRESUMEN
OBJECTIVE: Coronary calcification detected by CT is a marker for atherosclerotic disease with prognostic significance. However, potentially unstable plaque is characterized by a high lipid content rather than calcification, which may make detection using the calcium score difficult. To assess the prevalence and severity of atherosclerotic disease in patients without coronary calcification, we evaluated findings in patients with a normal calcium score undergoing coronary CT angiography (CTA). MATERIALS AND METHODS: Data from 794 consecutive coronary CTA examinations performed between February 2005 and May 2007 were reviewed. The calcium scores were determined as part of coronary CTA examinations, and calcium was quantified according to the Agatston method. Patients underwent coronary CTA because of high risk for coronary artery disease (53%) or atypical symptoms or abnormal stress test results (47%). On coronary CTA, plaque was characterized as mild disease without hemodynamically significant stenosis, moderate disease without hemodynamically significant stenosis, moderate stenosis (50-70% luminal narrowing), or severe stenosis (> 70% luminal narrowing). RESULTS: Of the 729 patients included in the study, 325 (45%) had a normal calcium score. Of these, 167 (51%) had noncalcified plaque on coronary CTA. Twelve (3.7%) of those with a normal calcium score had at least moderate stenosis, five (1.5%) of whom had severe stenosis. Eight of the 12 patients with significant stenosis underwent invasive angiography and coronary stenting. CONCLUSION: A considerable atheroma burden including significant stenoses may be present in patients with no coronary calcification. Although the calcium score does add prognostic value to standard risk factors and serum markers, imaging the vessel wall directly may be helpful to identify noncalcified plaque and guide therapy.
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Calcinosis/diagnóstico por imagen , Angiografía Coronaria/métodos , Enfermedad de la Arteria Coronaria/diagnóstico por imagen , Interpretación de Imagen Radiográfica Asistida por Computador/métodos , Tomografía Computarizada por Rayos X/métodos , Adolescente , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Reproducibilidad de los Resultados , Sensibilidad y EspecificidadRESUMEN
PURPOSE: To prospectively determine the prevalence and predictive value of three-dimensional (3D) and dynamic breast magnetic resonance (MR) imaging and contrast material kinetic features alone and as part of predictive diagnostic models. MATERIALS AND METHODS: The study protocol was approved by the institutional review board or ethics committees of all participating institutions, and informed consent was obtained from all participants. Although study data collection was performed before HIPAA went into effect, standards that would be compliant with HIPAA were adhered to. Data from the International Breast MR Consortium trial 6883 were used in the analysis. Women underwent 3D (minimum spatial resolution, 0.7 x 1.4 x 3 mm; minimal temporal resolution, 4 minutes) and dynamic two-dimensional (temporal resolution, 15 seconds) MR imaging examinations. Readers rated enhancement shape, enhancement distribution, border architecture, enhancement intensity, presence of rim enhancement or internal septations, and the shape of the contrast material kinetic curve. Regression was performed for each feature individually and after adjustment for associated mammographic findings. Multivariate models were also constructed from multiple architectural and dynamic features. Areas under the receiver operating characteristic curve (Az values) were estimated for all models. RESULTS: There were 995 lesions in 854 women (mean age, 53 years +/- 12 [standard deviation]; range, 18-80 years) for whom pathology data were available. The absence of enhancement was associated with an 88% negative predictive value for cancer. Qualitative characterization of the dynamic enhancement pattern was associated with an Az value of 0.66 across all lesion architectures. Focal mass margins (Az = 0.76) and signal intensity (Az = 0.70) were highly predictive imaging features. Multivariate models were constructed with an Az value of 0.880. CONCLUSION: Architectural and dynamic features are important in breast MR imaging interpretation. Multivariate models involving feature assessment have a diagnostic accuracy superior to that of qualitative characterization of the dynamic enhancement pattern.
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Neoplasias de la Mama/diagnóstico , Imagen por Resonancia Magnética/métodos , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Algoritmos , Teorema de Bayes , Neoplasias de la Mama/patología , Medios de Contraste/farmacocinética , Diagnóstico Diferencial , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Imagenología Tridimensional , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Estudios Prospectivos , Curva ROC , Análisis de Regresión , Sensibilidad y EspecificidadRESUMEN
OBJECTIVE: To estimate the added cancer yield of magnetic resonance imaging (MRI) over mammography in the contralateral breast of patients with a recent diagnosis of breast cancer. METHODS: We conducted a prospective, international study of mammography and MRI in women with a recent diagnosis of unilateral breast cancer. Each subject received a mammogram, clinical breast exam (CBE), and MRI of the unaffected breast within a 90 day time period. Definitive diagnosis of suspicious findings was determined through biopsy and central pathology review. RESULTS: Of the 103 eligible women included in study analyses, MRI detected 4 cancers in the contralateral breast while mammography detected none. MRI resulted in 12% (95% CI, 6%-20%) of women recommended for biopsy and 10% of women undergoing additional biopsy. The added cancer yield of MRI was 4% (95% CI, 1%-10%) and the positive predictive value of an abnormal MRI was 33% (95% CI, 10%-65%). Forty percent (4/10) of the biopsies performed based on the MRI recommendation were positive for malignancy. CONCLUSION: In women with a recent breast cancer diagnosis, approximately 4% will have an otherwise occult invasive breast cancer detected in the opposite breast by MRI alone.
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Neoplasias de la Mama/diagnóstico , Imagen por Resonancia Magnética , Neoplasias Primarias Múltiples/diagnóstico , Biopsia , Reacciones Falso Positivas , Femenino , Humanos , Mamografía , Persona de Mediana Edad , Neoplasias Primarias Múltiples/diagnóstico por imagen , Estudios Prospectivos , Sensibilidad y EspecificidadRESUMEN
BACKGROUND: The authors compared the performance of screening mammography versus magnetic resonance imaging (MRI) in women at genetically high risk for breast cancer. METHODS: The authors conducted an international prospective study of screening mammography and MRI in asymptomatic, genetically high-risk women age >/= 25 years. Women with a history of breast cancer were eligible for a contralateral screening if they had been diagnosed within 5 years or a bilateral screening if they had been diagnosed > 5 years previously. All examinations (MRI, mammography, and clinical breast examination [CBE]) were performed within 90 days of each other. RESULTS: In total, 390 eligible women were enrolled by 13 sites, and 367 women completed all study examinations. Imaging evaluations recommended 38 biopsies, and 27 biopsies were performed, resulting in 4 cancers diagnosed for an overall 1.1% cancer yield (95% confidence interval [95%CI], 0.3-2.8%). MRI detected all four cancers, whereas mammography detected one cancer. The diagnostic yield of mammography was 0.3% (95%CI, 0.01-1.5%). The yield of cancer by MRI alone was 0.8% (95%CI, - 0.3-2.0%). The biopsy recommendation rates for MRI and mammography were 8.5% (95%CI, 5.8-11.8%) and 2.2% (95%CI, 0.1-4.3%). CONCLUSIONS: Screening MRI in high-risk women was capable of detecting mammographically and clinically occult breast cancer. Screening MRI resulted in 22 of 367 of women (6%) who had negative mammogram and negative CBE examinations undergoing biopsy, resulting in 3 additional cancers detected. MRI also resulted in 19 (5%) false-positive outcomes, which resulted in benign biopsies.