Michael R. Williamson

The New Mexico Mammography Project: Screening mammography performance in Albuquerque, New Mexico, 1991 to 1993

This project was designed to collect and link population‐based mammography and breast carcinoma data to assess the performance of community mammography screening.

Hemorrhagic Adrenal Metastases: CT Findings

Adrenal hemorrhage secondary to metastases is uncommon. We have encountered four such cases that presented as large adrenal masses. In all cases the CT findings were of an inhomogeneous mixed-density adrenal mass with extensive perirenal changes suggestive of perirenal hemorrhage or mass. When such a lesion is seen, hemorrhagic adrenal metastases should be considered. Fluid may be of high density, suggestive of hemorrhage. However, as the adrenal is in the perinephric space, hemorrhage from any cause (trauma, metastases, or anticoagulant) in the adrenal gland will gravitate into the perinephric space.

Case report. MR and CT appearance of cardiac hemangioma.

We present a case of cardiac hemangioma in a symptomatic patient. MR and CT each have specific characteristics that should make one consider including or excluding this in the differential diagnosis of a cardiac tumor.

Osteomyelitis: sensitivity of 0.064 T MRI, three-phase bone scanning and indium scanning with biopsy proof.

We compared the ability of magnetic resonance imaging (MRI) using a 0.064 T permanent magnet, three-phase bone scanning, and indium-labeled white blood cell (111In-WBC) scanning, to diagnose osteomyelitis. Twenty-three patients underwent biopsy. All patients were examined at presentation with all three modalities. Sensitivities for each modality were calculated using biopsy as a gold standard. The results were 72% for MRI, 68% for bone scan, and 45% for 111In-WBC. Specificities were not calculated because of lack of negative biopsies. MRI was as sensitive as bone scanning in the diagnosis of osteomyelitis. All modalities had lower than previously reported sensitivities for imaging osteomyelitis.

Distinguishing Hantavirus pulmonary syndrome from acute respiratory distress syndrome by chest radiography : Are there different radiographic manifestations of increased alveolar permeability ?

Hantavirus infection may cause diffuse air space disease, termed hanta-virus pulmonary syndrome (HPS). The authors sought to determine if chest radiographs could differentiate HPS from typical acute respiratory distress syndrome (ARDS). The authors identified patients with either HPS (n = 11) or acute ARDS (n = 32) and selected the earliest chest radiograph showing diffuse airspace disease, and a chest radiograph taken 24 to 48 hours previously. Thoracic and general radiologists first viewed the chest radiograph showing diffuse air space disease, and ranked the likelihood that each case represented HPS versus ARDS. Afterward, readers viewed earlier chest radiographs and rescored each case. Receiver operating characteristic (ROC) curves from both scoring sessions were generated. The mean areas under the ROC curves for the entire group was 0.83 ± 0.12 initially, and improved to 0.87 ± 0.09 (p < 0.05) after viewing prior chest radiographs. Receiver operating characteristic curves of thoracic radiologists described greater areas than those of general radiologists both before and after viewing prior chest radiographs; 0.95 ± 0.01 versus 0.78 ± 0.08 (p < 0.05) and 96 ± 0.02 versus 0.80 ± 0.05 (p < 0.05). The mean sensitivity and specificity of chest radiograph interpretation for HPS was 86 ± 13% and 74 ± 11%, respectively. Chest radiographs can differentiate HPS from ARDS. Accuracy is improved by the use of serial radiographs and more highly trained readers. The chest radiograph findings may represent differences in the extent of alveolar epithelial damage seen in HPS and ARDS.

Computer‐based collection of mammographic exposure data for quality assurance and dosimetry

PURPOSE There is potentially more to quality assurance in mammography than the MQSA mandated tests. In this paper we describe a method of capturing individual mammogram technical parameters and the creation of new measures. These include the numbers of images required for each screening examination by technologist, median compression by technologist, and the radiation dose of the examination to the general population of patients. METHOD/MATERIALS With this method we describe a semiautomated method of the collection of technical data from mammography exposures. The data that are automatically created by the mammography unit are saved on a computer for later analysis. The method was used on 2738 consecutive screening mammography examinations and 13 621 exposures from one machine. Data were obtained from November 1998 through December 1999. RESULTS Using standard methods, the mean glandular dose (MGD) per exposure was 2.62 mGy (SD 1.2). The mean dose per bilateral screening examination was 6.53 mGy (SD 3.07), the median dose was 6.11 mGy, and the dose range was 1.13-34.23 mGy. Rhodium filtration was used for 18% of the exposures. The average and median breast thickness was 4.9 cm. The ACR phantom MGD for this machine was 2.44 mGy at 25 kVp, and 1.97 mGy at 26 kVp. The mean number of exposures for a bilateral mammogram was 4.9, and varied by a technologist from 4.7 to 5.2. The mean compression pressure varied by technologist from 13 to 30 lbs (58-134 N). CONCLUSIONS The mean dose per mammogram is slightly greater than the ACR phantom dose at 25 kVp. Almost five exposures were necessary for a standard bilateral examination, and this varied by technologist. The compression used also varied by technologist. The semiautomated collection of technical data can aid in maintaining an effective mammography QA program.

Osteoporosis: diagnosis by plain chest film versus dual photon bone densitometry

Readers of chest radiographs often comment on the presence of osteoporosis. We have hypothesized that diagnoses of osteoporosis from chest films are not reliable even when made by experienced radiologists. To test this hypothesis, we had nine radiologists estimate the degree of bone density seen on 45 lateral chest films. We compared their estimates of bone density to the results of dual photon bone densitometry of the lumbar spine. We found that there was little ability to accurately diagnose osteoporosis by chest film since the group of nine readers achieved accuracies ranging from 0.59 to 0.64. Therefore, we feel it is unjustified to comment upon the presence or absence of osteoporosis on the basis of chest films.

Avascular necrosis of the capitate demonstrated on a 0.064 T magnet

We report the first case of avascular necrosis of a carpal bone to be imaged on a 0.064 Tesla magnet, one of the lowest field strength magnetic resonance imaging systems currently available.

Gorham's syndrome. Correlative imaging using nuclear medicine, plain film, and 3-D CT.

The authors present a case of Gorhams syndrome involving the mandible in a 52-year-old man demonstrated by multiple imaging modalities. Gorhams Syndrome (diseappearing bone disease, massive osteolysis) is a rare idiopathic disorder of bone characterized radiographically by progressive bony resorption. The process is usually monostotic in the initial phase with involvement of adjacent bones by direct spread across joint spaces. The clinical course is unpredictable with spontaneous arrest of the osteolysis being common

Detecting breast microcalcifications using super-resolution ultrasound imaging: a clinical study

Imaging breast microcalcifications is crucial for early detection and diagnosis of breast cancer. It is challenging for current clinical ultrasound to image breast microcalcifications. However, new imaging techniques using data acquired with a synthetic-aperture ultrasound system have the potential to significantly improve ultrasound imaging. We recently developed a super-resolution ultrasound imaging method termed the phase-coherent multiple-signal classification (PC-MUSIC). This signal subspace method accounts for the phase response of transducer elements to improve image resolution. In this paper, we investigate the clinical feasibility of our super-resolution ultrasound imaging method for detecting breast microcalcifications. We use our custom-built, real-time synthetic-aperture ultrasound system to acquire breast ultrasound data for 40 patients whose mammograms show the presence of breast microcalcifications. We apply our super-resolution ultrasound imaging method to the patient data, and produce clear images of breast calcifications. Our super-resolution ultrasound PC-MUSIC imaging with synthetic-aperture ultrasound data can provide a new imaging modality for detecting breast microcalcifications in clinic without using ionizing radiation.