Cerebral hemodynamics in preterm infants during positional intervention measured with diffuse correlation spectroscopy and transcranial Doppler ultrasound.

Four very low birth weight, very premature infants were monitored during a 12 degrees postural elevation using diffuse correlation spectroscopy (DCS) to measure microvascular cerebral blood flow (CBF) and transcranial Doppler ultrasound (TCD) to measure macrovascular blood flow velocity in the middle cerebral artery. DCS data correlated significantly with peak systolic, end diastolic, and mean velocities measured by TCD (p(A) =0.036, 0.

Delta-projection imaging on contrast-enhanced ultrasound to quantify tumor microvasculature and perfusion.

Rationale And Objectives: The aim of this study was to assess the Delta-projection image processing technique for visualizing tumor microvessels and for quantifying the area of tissue perfused by them on contrast-enhanced ultrasound images.

Materials And Methods: The Delta-projection algorithm was implemented to quantify perfusion by tracking the running maximum of the difference (Delta) between the contrast-enhanced ultrasound image sequence and a baseline image. Twenty-five mice with subcutaneous K1735 melanomas were first imaged with contrast-enhanced grayscale and then with minimum-exposure contrast-enhanced power Doppler (minexCPD) ultrasound.

Predicting PSA response of prostate cancer to radiation therapy with Doppler sonography.

Objective: We report a prospective investigation of the correlation between pretreatment Doppler vascular density (DVD) of the entire prostate gland and subsequent prostate-specific antigen (PSA) response following external beam radiation therapy, for patients with low- or intermediate-risk prostate cancer. This report updates a previous report (Sehgal et al., Acad Radiol 2003;10:366) with longer patient follow-up and additional quantitative and clinically relevant end points.

A review of breast ultrasound.

Frequent advances in transducer design, electronics, computers, and signal processing have improved the quality of ultrasound images to the extent that sonography is now a major mode of imaging for the clinical diagnosis of breast cancer. Breast ultrasound is routinely used for differentiating cysts and solid nodules with high specificity. In combination with mammography, ultrasound is used to characterize solid masses as benign or malignant.

Diffuse boundary extraction of breast masses on ultrasound by leak plugging.

We propose a semiautomated seeded boundary extraction algorithm that delineates diffuse region boundaries by finding and plugging their leaks. The algorithm not only extracts boundaries that are partially diffuse, but in the process finds and quantifies those parts of the boundary that are diffuse, computing local sharpness measurements for possible use in computer-aided diagnosis. The method treats a manually drawn seed region as a wellspring of pixel "fluid" that flows from the seed out towards the boundary.

Teaching medical students diagnostic sonography.

Objective: The purpose of this pilot project was to train medical students in sonography.

Methods: Thirty-three medical students participated in a pilot sonography course, which included exposure to ultrasound physics, knobology of a compact ultrasound scanner, training in scanning and anatomy of the aorta and right kidney, and reading assignments in these areas. Pretraining and posttraining examinations were given in these areas to analyze the degree of knowledge gained by these methods.

Comparative analysis of logistic regression and artificial neural network for computer-aided diagnosis of breast masses.

Rationale And Objective: To compare logistic regression and artificial neural network for computer-aided diagnosis on breast sonograms.

Materials And Methods: Ultrasound images of 24 malignant and 30 benign masses were analyzed quantitatively for margin sharpness, margin echogenicity, and angular variation in margin. These features and age of patients were used with two pattern classifiers, logistic regression, and an artificial neural network to differentiate between malignant and benign masses.

Computer-based margin analysis of breast sonography for differentiating malignant and benign masses.

Objective: To evaluate the role of quantitative margin features in the computer-aided diagnosis of malignant and benign solid breast masses using sonographic imaging.

Methods: Sonographic images from 56 patients with 58 biopsy-proven masses were analyzed quantitatively for the following features: margin sharpness, margin echogenicity, and angular variation in margin. Of the 58 masses, 38 were benign and 20 were malignant.

Color and power Doppler sonography in the diagnosis of prostate cancer: comparison between vascular density and total vascularity.

Objective: Advances in color flow Doppler (CFD) and power Doppler imaging (PDI) have potential for prostate cancer diagnosis. Previous reports based on qualitative assessment suggest that hypervascularity increases likelihood of prostate cancer. Our objective was to compare 2 methods of vascularity assessment using PDI: total vascularity (TV) and vascular density (VD).

Brachial artery: measurement of flow-mediated dilatation with cross-sectional US--technical validation.

Ultrasonographic examination of flow phantoms and the brachial artery of a healthy volunteer undergoing reactive hyperemia was performed. Images were analyzed with a user-guided automated boundary detection (UGABD) algorithm to extract boundaries and measure cross-sectional area. UGABD correctly detected pulsatile vasomotion and measured area within 5% of the true value.

Multigated contrast-enhanced power Doppler to measure blood flow in mice tumors.

This study evaluated an image-gating method using contrast-enhanced power Doppler ultrasound (US) to estimate blood perfusion in mice tumors. A mathematical model that compensates for the effect of bubble destruction by US pulses was used to determine contrast flow through an image plane. Multigated power Doppler images were obtained following contrast injection.

Correlation between Doppler vascular density and PSA response to radiation therapy in patients with localized prostate carcinoma.

Rationale And Objectives: The authors performed this study to ascertain whether there is a correlation between pretreatment Doppler vascular density (DVD) of the prostate and prostate-specific antigen (PSA) response following radiation therapy in prostate cancer patients.

Materials And Methods: Prior to radiation therapy, 14 patients with biopsy-proven carcinoma (of Gleason grades 2-7) were imaged with transrectal ultrasound in gray-scale, color Doppler, and power Doppler modes. The Doppler images were analyzed for mean DVD with the aid of a computer program.

Using sonography to examine adult patients at an academic medical center: have usage patterns changed with the expansion of managed care?

Objective: This study was designed to determine whether significant changes have occurred in the utilization of sonography relative to more expensive cross-sectional imaging techniques in adult patients during a time of increasing reliance on managed care.

Materials And Methods: Use of sonography was compared with use of CT and MR imaging of the abdomen, pelvis, and retroperitoneum in adult patients in 1993 and 1998 at an academic medical center. Clinicians who requested the greatest number of examinations in both years were surveyed to assess their perception of changes in their practice patterns during the interim.

Does use of a PACS increase the number of images per study? A case study in ultrasound.

The purpose of this study was to determine if the use of a picture archiving and communications system (PACS) in ultrasonography increased the number of images acquired per examination. The hypothesis that such an increase does occur was based on anecdotal information; this study sought to test the hypothesis. A random sample of all ultrasound examination types was drawn from the period 1998 through 1999.

Impact of added biopsy areas on prostate cancer detection: preliminary analysis.

Objective: To evaluate variations in prostate cancer detection relevant to the number and areas of biopsy cores.

Methods: Ninety patients with elevated prostate-specific antigen levels, abnormal physical examination findings, or both had ultrasound examinations plus biopsies. Forty-nine patients had 11 biopsies, and 41 patients had 6 biopsies.

Renal blood flow changes induced with endothelin-1 and fenoldopam mesylate at quantitative Doppler US: initial results in a canine study.

Purpose: To evaluate quantitative Doppler ultrasonography (US) for assessing renal blood flow changes induced with endothelin-1 (ET-1) and fenoldopam mesylate in conscious dogs.

Materials And Methods: A blood flow probe was surgically implanted around the renal artery in eight adult dogs. Color and power Doppler US images were acquired in conscious restrained dogs during intravenous infusion of ET-1 and fenoldopam mesylate.

Interreader variability and predictive value of US descriptions of solid breast masses: pilot study.

Rationale And Objectives: This study evaluated the specificity of ultrasound (US) characteristics of solid breast lesions and the interreader variability in their interpretation.

Materials And Methods: In 61 patients, 70 sonographically visible solid masses, scheduled for biopsy because of findings from conventional imaging, were prospectively and sequentially accrued for evaluation. Three readers interpreted the sonograms and described the solid masses in terms of established US characteristics.

Quantitative vascularity of breast masses by Doppler imaging: regional variations and diagnostic implications.

Seventy-four biopsy proven breast masses were imaged by color and power Doppler imaging to evaluate vascular pattern of malignant and benign breast masses. The images were analyzed for vascularity. The measurements were made over the entire mass as well as regionally at its core, at its periphery, and in the tissue surrounding it.

Evaluation of change in blood flow by contrast-enhanced power Doppler imaging during norepinephrine-induced renal vasoconstriction.

We evaluated the changes in flow induced by intrarenal infusion of norepinephrine by an ultrasonographic contrast agent and power Doppler imaging. Hypoperfusion was induced in dogs (N = 5) by infusing norepinephrine directly into the renal artery for 30 min at doses of 0.7 microg/kg/min, 1.

Sonography during early pregnancy: dependence of threshold and discriminatory values on transvaginal transducer frequency.

Objective: Our goal was to determine if normal and abnormal pregnancies could be distinguished at smaller sac sizes with a higher frequency transvaginal transducer than with a 5-MHz transducer.

Subjects And Materials: Thirty-nine patients with potentially abnormal pregnancies identified with a 5-MHz transvaginal transducer were immediately reimaged with a 9-5-MHz transducer. We compared our ability to visualize the yolk sac, embryo, and cardiac activity relative to mean sac diameter on imaging at both frequencies in women with normal and abnormal pregnancies.

The effect of androgen deprivation on the early changes in prostate volume following transperineal ultrasound guided interstitial therapy for localized carcinoma of the prostate.

Purpose: To determine the change in volume of the prostate as a result of neoadjuvant androgen deprivation prior to prostate implant and in the early postimplant period following transperineal ultrasound guided palladium-103 brachytherapy for early-stage prostate cancer.

Methods And Materials: Sixty-nine men received 3 to 6 months of androgen deprivation therapy followed by treatment planning ultrasound followed 4 to 8 weeks later by palladium-103 implant of the prostate. All patients had clinical and radiographic stage T1c-T2b adenocarcinoma of the prostate.

Diagnosis and staging of ovarian cancer: comparative values of Doppler and conventional US, CT, and MR imaging correlated with surgery and histopathologic analysis--report of the Radiology Diagnostic Oncology Group.

Purpose: To determine the optimal imaging modality for diagnosis and staging of ovarian cancer.

Materials And Methods: Two hundred eighty women suspected to have ovarian cancer were enrolled in a prospective study before surgery. Doppler ultrasonography (US), computed tomography (CT), and magnetic resonance (MR) imaging were used to evaluate the mass; conventional US, CT, and MR imaging were used to stage spread.

Comparison of power Doppler and B-scan sonography for renal imaging using a sonographic contrast agent.

The goal of this study was to evaluate the relative performance of power Doppler and B-scan imaging modes in detecting vascular perfusion changes resulting from injection of a contrast agent. To allow this comparison the imaging plane and the contrast agent injection must be the same for both modes. We achieved this by using a rigid transducer holder and simultaneously recording power Doppler and B-scan images on separate videotapes.

Comparison of resistive index versus pulsatility index in assessing the benign etiology of adnexal masses.

Retrospective analysis of pelvic sonograms with colorguided spectral Doppler evaluation of 189 adnexal masses yielded four malignancies, 20 benign neoplasms, 32 cysts, and 14 endometriomas. Fifty-eight masses were presumed benign on additional imaging. Pulsatility index (PI) < 1.