Biomedical subjects

William J Weadock

Publications and source records attributed to William J Weadock.

10 recordsLinked to original sources

PubMed2006

MRI of sonographically indeterminate adnexal masses.

OBJECTIVE: The purpose of this study was to assess the ability of MRI to characterize sonographically indeterminate adnexal masses and to define the sonographic features contributing to indeterminate diagnoses. MATERIALS AND METHODS: Two blinded radiologists retrospectively reviewed the MRI examinations of 87 patients with 95 sonographically indeterminate adnexal masses. Reviewers determined the origin of a mass, its tissue content (cystic, solid, complex cystic, or cystic and solid), tissue characteristics (fat, blood, fibrous, or leiomyomatous), and benignity versus malignancy. Sonograms were reviewed by three reviewers to determine the origin of a mass, its tissue content, and reasons for an indeterminate diagnosis. Sensitivity and specificity of MRI were calculated, and agreement of sonography and MRI with the final diagnosis was determined using kappa statistics. The final diagnosis was determined by histopathology, surgical findings, or imaging or clinical follow-up. RESULTS: The sensitivity of MRI for identifying malignancy (n = 5) was 100% and its specificity for benignity (n = 90) was 94%. Excellent agreement was seen between MRI and the final diagnosis for determining the origin (kappa = 0.93), tissue content (kappa = 0.98), and tissue characteristics (kappa = 0.91) of a mass. Sonography had poor agreement with the final diagnosis for the origin (kappa = 0.19) and tissue content (kappa = 0.33) of a mass. The main reasons for indeterminate sonographic diagnoses were the inability to determine origin because of location and large mass size and the appearances of purely solid or complex cystic masses. CONCLUSION: Sonographically indeterminate adnexal masses of uncertain origin and solid or complex cystic content benefit from further evaluation with MRI, which is highly accurate for identifying the origin of a mass and characterizing its tissue content, obviating surgery.

Adnexa Uteri↗

PubMed2005

A novel application of the MIRC repository in medical education.

Medical students on the radiology elective in our institution create electronic presentations to present to each other as part of the requirements for the rotation. Access was given to previous students' presentations via the web-based system, Medical Imaging Resource Center (MIRC) project, created and supported by the Radiological Society of North America (RSNA). RadPix Power 2 MIRC (Weadock Software, LLC, Ann Arbor, MI) software converted the Microsoft PowerPoint (Redmond, WA) presentations to a MIRC-compatible format. The textual information on each slide is searchable across the entire MIRC database. Future students will be able to benefit from the work of their predecessors.

Computer-Assisted Instruction↗

PubMed2005

Magnetic resonance imaging and 3-dimensional analysis of external anal sphincter anatomy.

OBJECTIVE: To use magnetic resonance images of living women and 3-dimensional modeling software to identify the component parts and characteristic features of the external anal sphincter (EAS) that have visible separation or varying origins and insertions. METHODS: Detailed structural analysis of anal sphincter anatomy was performed on 3 pelvic magnetic resonance imaging (MRI) data sets selected for image clarity from ongoing studies involving nulliparous women. The relationships of anal sphincter structures seen in axial, sagittal, and coronal planes were examined using the 3-D Slicer 2.1b1 software program. The following were requirements for sphincter elements to be considered separate: 1) a clear and consistently visible separation or 2) a different origin or insertion. The characteristic features identified in this way were then evaluated in images from an additional 50 nulliparas for the frequency of feature visibility. RESULTS: There were 3 components of the EAS that met criteria as being "separate" structures. The main body (EAS-M) is separated from the subcutaneous external anal sphincter (SQ-EAS) by a clear division that could be observed in all (100%) of the MRI scans reviewed. The wing-shaped end (EAS-W) has fibers that do not cross the midline ventrally, but have lateral origins near the ischiopubic ramus. This EAS-W component was visible in 76% of the nulliparas reviewed. CONCLUSION: Three distinct external anal sphincter components can be identified by MRI in the majority of nulliparous women.

Adult↗

PubMed2004

T2-weighted MR imaging in the assessment of cirrhotic liver.

PURPOSE: To assess if T2-weighted magnetic resonance (MR) imaging provides added diagnostic value in combination with dynamic gadolinium-enhanced MR imaging in the detection and characterization of nodular lesions in cirrhotic liver. MATERIALS AND METHODS: Two readers retrospectively and independently analyzed 54 MR imaging studies in 52 patients with cirrhosis. In session 1, readers reviewed T1-weighted and dynamic gadolinium-enhanced images. In session 2, readers reviewed T1-weighted, dynamic gadolinium-enhanced, and respiratory-triggered T2-weighted fast spin-echo images. Readers identified and characterized all focal lesions by using a scale of 1-4 (1, definitely benign; 4, definitely malignant). Multireader correlated receiver operating characteristic (ROC) analysis was employed to assess radiologist performance in session 2 compared with session 1. The difference in the areas under the ROC curves for the two sessions was tested. In a third session, readers assessed conspicuity of biopsy-proved lesions on T2-weighted MR images by using a scale of 1-3 (1, not seen; 3, well seen) and identified causes of reduced conspicuity. RESULTS: Two additional benign lesions were detected by each reader in session 2. Fifty-five lesions had pathologic verification, including 32 malignant, three high-grade dysplastic, and 20 benign nodules. There was no significant difference in the area under the ROC curves between the two sessions (P =.48). Thirty-two lesions were inconspicuous on T2-weighted MR images because of parenchymal heterogeneity, breathing artifacts (particularly in patients with ascites), and lesion isointensity with liver parenchyma. T2-weighted MR imaging was useful in the evaluation of cysts and lymph nodes. CONCLUSION: T2-weighted MR imaging does not provide added diagnostic value in the detection and characterization of focal lesions in cirrhotic liver.

Adult↗

PubMed2004

MRI for preoperative staging of renal cell carcinoma using the 1997 TNM classification: comparison with surgical and pathologic staging.

OBJECTIVE: The purpose of our study was to determine the accuracy of MRI for preoperative staging of renal cell carcinoma using the 1997 TNM classification. MATERIALS AND METHODS: We conducted a retrospective review of MRI performed in 40 consecutive patients with 42 renal cell carcinomas before radical (n = 35) or partial (n = 4) nephrectomy or exploratory laparotomy (n = 3). The interval between imaging and surgery ranged from 1 to 59 days (mean, 17.9 days). Imaging was performed with T1- and T2-weighted, dynamic gadolinium-enhanced, and time-of-flight sequences. MRI and surgical-pathologic staging was performed using the 1997 TNM staging system. MRI staging was compared with surgical-pathologic staging as the gold standard. Agreement between the two staging methods was assessed using the kappa statistic. RESULTS: Agreement between MRI and surgical-pathologic staging was good for T staging (kappa = 0.72 and 0.78 for reviewers 1 and 2 respectively), poor for N staging (kappa = 0.13, both reviewers), good for M staging (kappa = 0.66, both reviewers), and excellent for the assessment of venous involvement (kappa = 0.93, both reviewers). MRI overestimated the T stage in five patients and the N stage in five and underestimated the T stage in three, the N stage in four, the M stage in one, and the extent of venous thrombosis in two patients. CONCLUSION: MRI is a reliable method for preoperative staging of renal cell carcinoma using the 1997 TNM classification, in particular for assessing venous involvement.

Adolescent↗

PubMed2003

Hepatic arterial phase MR imaging with automated bolus-detection three-dimensional fast gradient-recalled-echo sequence: comparison with test-bolus method.

Sixty-two patients underwent magnetic resonance (MR) imaging of the liver with the automated contrast material bolus-detection technique. Arterial phase MR images were assessed quantitatively and qualitatively. In 23 patients, a test bolus of contrast material was injected intravenously before dynamic MR imaging. There was good correlation and agreement between delay times estimated with both timing methods. Eighty-three percent of arterial phase images obtained with automated contrast material bolus detection were optimal. There was good correlation and agreement between delay times estimated with both timing methods. Optimal hepatic arterial phase MR images can be obtained routinely with automated detection of a contrast material bolus.

Adult↗

PubMed2002

Imaging of the post-treatment larynx.

The treatment for squamous cell carcinoma of the upper aerodigestive tract includes surgery, radiation therapy (RT), chemotherapy or a combination of various modalities. Familiarization with the expected imaging changes following therapy allow accurate evaluation of imaging studies and may prevent misinterpretation of post-treatment changes as recurrent disease. The intent of this manuscript will be to review the post-treatment appearance of the larynx following RT and various types of laryngectomy.

Carcinoma, Squamous Cell↗

PubMedDate not supplied

Multiparametric color-encoded brain MR imaging in Talairach space.

Clinical magnetic resonance (MR) imaging of the brain is typically performed in the standard three orthogonal planes of the magnet, with little regard to head positioning. Multiple sequences with different imaging parameters are performed, and gray-scale images are obtained and displayed separately. The authors have implemented, and currently advocate, the routine acquisition of coregistered transverse images after roll, yaw, and pitch correction to Talairach space. Talairach, anterior commissure (AC)-posterior commissure (PC) referenced, stereotactic space has been widely embraced by the neuroscience community. This standardization should lead to more reproducible and readily interpretable MR examinations. A method is described to obtain direct AC-PC referenced (Talairach space) MR images. Sample protocols are provided. Coregistered T1-weighted, T1-weighted with contrast material administration, T2-weighted, fluid-attenuated inversion recovery (FLAIR), MR angiography, fractional anisotropy, and functional MR imaging sequences are presented, depicting a wide range of imaging parameters applied to normal brain anatomy in Talairach space. Illustrative examples of pathology are also provided. Color encoding is discussed and exploited to display and integrate multiparameter MR imaging contrast and white-matter-tract direction (anisotropy). The color composites may reduce the number of images needed for review by a factor of three or four and facilitate interpretation.

Brain↗

PubMedDate not supplied

Improving educational computer exhibits at radiologic meetings by modifying computer environment: results of an observational study.

An observational study of educational computer exhibits (ECEs) at the 86th Scientific Assembly and Annual Meeting of the Radiological Society of North America in 2000 was performed to determine the frequency with which the ECEs were in working order. At any given time, an average of 10% of the 71 exhibits were found to be inoperable, and, although some exhibits were functioning 100% of the time, others were not functioning up to 55% of the time. These observations underscore the importance of careful design when creating a computer-based exhibit for a meeting. Downtime of ECEs at meetings is the result of both intentional and unintentional user actions. Given that traditional poster presentations are "working" 100% of the time, modifications made to the environment of an exhibit computer to reduce downtime would be beneficial. Several relatively easy computer configuration steps can be taken that will likely improve the amount of time that an exhibit is functional. Electronic exhibits allow a more interactive experience for users and, with some assistance, will continue to be an effective educational tool.

Audiovisual Aids↗

PubMedDate not supplied

Cardiovascular MR imaging: technique optimization and detection of disease in clinical practice.

Magnetic resonance (MR) imaging has emerged as an important and growing means of cardiovascular imaging, with many advantages over other radiologic modalities, including excellent spatial and temporal resolution, lack of ionizing radiation, and noninvasiveness. In this article, the utility of MR imaging in cardiovascular imaging and in the diagnosis of cardiovascular disease will be discussed. MR techniques for evaluating the heart and vasculature will be described, and troubleshooting techniques will be presented. Imaging findings in congenital anomalies such as septal defects, patent ductus arteriosus, transposition of the great arteries, and tetralogy of Fallot will be identified. Valvular lesions and methods for evaluating valvular function will be discussed. MR imaging findings in acquired disorders such as aneurysms and pericardial disease will be described.

Cardiovascular Diseases↗