Christopher R. B. Merritt

The identification of ulcerative plaque with high resolution duplex carotid scanning

A retrospective study evaluated 50 patients who had pathologically proven intraplaque hemorrhage. The patients were pathologically divided into two groups by the presence or absence of intimal ulcerations. These two groups were then sonographically compared with regard to surface characteristics of the plaque, plaque size, size of the sonolucent area within the plaque, and location of the sonolucent area relative to the intimal surface. No defined sonographic characteristics could be used to separate these two groups of patients with heterogeneous plaques into those who had or did not have ulcerations. Most importantly, merely sonographically evaluating the surface of the plaque to determine if it was smooth or irregular could not be used as a successful means to identify which patients were at risk for ulceration.

On the Usefulness of the Mechanical Index Displayed on Clinical Ultrasound Scanners for Predicting Contrast Microbubble Destruction

The purpose of this study was to evaluate the mechanical index (MI) displayed on clinical ultrasound scanners as a predictor of exposure conditions related to the destruction of sonographic microbubble contrast agents.

Sonography of palpable breast cancer

Because of the increasing use of sonography to rule out cancer in women with palpable breast abnormalities, this study was performed to determine the rate of sonographically occult malignancy in this clinical setting.

Diagnosing Breast Lesions With Contrast-Enhanced 3-Dimensional Power Doppler Imaging

Objective. To compare mammography with contrast‐enhanced 2‐ and 3‐dimensional power Doppler imaging for the diagnosis of breast cancer. Methods. Fifty‐five patients, who underwent breast biopsies with histopathologic assessment, participated in a study of mammography and contrast‐enhanced sonography. Levovist (Berlex Laboratories, Montville, NJ) and Optison (Mallinckrodt, St Louis, MO) were administrated to 22 and 33 patients, respectively. Precontrast and postcontrast 2‐dimensional power Doppler data of the lesion were obtained with an HDI 3000 system (Philips Medical Systems, Bothell, WA), and 3‐dimensional data were acquired with an LIS 6000A system (Life Imaging Systems Inc, London, Ontario, Canada). Two independent and blinded readers assessed diagnosis. Receiver operating characteristic curves were computed individually and in combination for mammography and 2‐ and 3‐dimensional sonography (before and after contrast). Histopathologic and imaging parameters were compared by Mann‐Whitney statistics. Results. Mammographic findings were available for 50 patients, biopsy for 54, and 2‐ and 3‐dimensional sonographic images for 53 and 52, respectively. Of the 50 patients who had all 4 measures, 15 (30%) had malignancies. The areas under the receiver operating characteristic curve for the diagnosis of breast cancer were 0.51 for 2‐dimensional contrast‐enhanced imaging, 0.60 for 3‐dimensional power Doppler imaging, and 0.76 for 3‐dimensional contrast‐enhanced imaging (P < .01). Mammography produced an area of 0.86, which increased when combined with 3‐dimensional contrast‐enhanced imaging to 0.90 and with all sonographic modalities to 0.96 (P < .001). The histopathologic diagnosis of benign or malignant correlated with the presence or absence of anastomoses and with the degree of vascularity assessed with contrast‐enhanced 3‐dimensional power Doppler imaging (P = .007 and .02). Conclusions. Contrast‐enhanced 3‐dimensional power Doppler imaging increases the ability to diagnose breast cancer relative to conventional 2‐ and 3‐dimensional sonographic imaging.

Doppler color flow imaging of carotid artery dissection.

The incidence of carotid artery dissections complicating an aortic dissection is reported to be 15%. In the past, the radiographic identification of these dissections has been made primarily with arteriography. There have been three cases reported in the literature which describe the ability to identify carotid dissection with high resolution ultrasound. l.J This report describes two cases in which the diagnosis was made with the use of Doppler color flow imaging (Quantum Medical Systems; Issaquah, WA). With this new technique, the diagnosis of dissection can be made easily and rapidly, and direction of flow in both lumens can be identified and quantified. Preoperative evaluation of patients with suspected aortic dissection often includes angiography. Aortic dissections, however, may be missed by angiography alone when filling of the false lumen does not occur. •.s Ultrasonographic evaluation of accessible arteries offers the advantage of demonstrating a false lumen, even if this lumen is thrombosed. Two cases of aortic dissection with se£ondary common carotid artery dissections were evaluated postoperatively by Doppler color flow imaging. We discuss advantages of this new imaging modality in the preoperative and postoperative evaluation of carotid artery dissections. CASE REPORTS

Megavoltage portal films using computed radiographic imaging with photostimulable phosphors.

Conventional portal films taken with high-energy x rays are severely impaired by poor image quality, and many attempts have been made to overcome this problem. A new technology, computed radiographic imaging, has been investigated as a means of producing images taken with 6-and 10-MV x rays. The computed radiographic imaging (CRI) system is based on the principle of laser-stimulated luminescence induced in an image receptor plate exposed to ionizing radiation, and direct conversion of the light into digital form. Image processing using contrast enhancement and unsharp masking yields images at least as good as the best portal films obtainable with conventional commercial radiotherapy cassettes. Additionally, CRI offers advantages of reduced image size and digital storage. The system is capable of producing normal film densities over an extremely wide range of exposure.

Cholelithiasis in ileostomy patients.

A retrospective study of 152 ileostomates with inflammatory bowel disease (IBD) revealed that 16 patients (10.5 per cent) had diagnoses of cholelithiasis before, at the time of, or after having ileostomies. Of the remaining patients, 69 were followed for possible cholelithiasis, most of those with sonographic examination. Sixteen of this latter group of patients (23.2 per cent) were found to have cholelithiasis, usually in an asymptomatic stage. Among women over 50 years old, seven of 11 (63.6 per cent) had gallstones. Due to this high prevalence of cholelithiasis, gallbladder imaging is recommended as a part of the preoperative workup and follow-up of ileostomates. Prophylactic cholecystectomy may be carefully considered in female patients with IBD at the time of proctocolectomy.

Usefulness of duplex ultrasound in evaluating vertebral arteries

A criticism of duplex scanning of the carotid vessels is that the study is limited to evaluation of the carotid bifurcations, whereas with other vascular imaging studies the vertebral vessels can also be seen. We have prospectively collected data on our ability to evaluate the vertebral vessels on all patients who are sent for carotid evaluations. We have scanned 677 patients and have identified flow in one or both vertebral arteries in nearly 90% of these patients. Therefore, we urge that evaluation of vertebral vessels be made a routine part of the standard carotid duplex ultrasound examination.