Like Us and Follow Us on

May 27, 2011

ARDMS Updates and Headlines in the News:

Promising Results for 3D Ultrasound/MRI Prostate Biopsy

Target Prophylaxis Shows Promise in Addressing post-TRUSP Infections

Ultrasound Should be First-line Approach for Pediatric Urinary Tract Infections

Ultrasound Fellowship Aims to Train Emergency Department Physicians

*Clicking this link will take you away from the NewsWire newsletter.

Promising Results for 3D Ultrasound/MRI Prostate Biopsy

Researchers at the University of California, Los Angeles (UCLA) have demonstrated preliminary accuracy in the use of 3D ultrasound tracking and MR image fusion for biopsy of suspected prostate cancers, according to a study published in the journal of Urologic Oncology.

“Virtually all major cancers can be easily imaged within the organ of origin, but not [prostate cancer],” noted Shyam Natarajan, MS, from the Biomedical Engineering Interdepartmental Program at UCLA, and co-authors. “Imaging prostate cancer (CaP), while in a curable state, has proven elusive, despite a half-century of interest and effort.”

Natarajan pointed to similarity between benign and cancerous tissue in the prostate, heterogeneity of prostate tissue in aging men and limited resolving power of imaging as posing significant challenges to accurate imaging and diagnosis of prostate cancer.

Highlighting advances such as 3T MRI, the researchers performed a trial on 218 patients of an ultrasound biopsy tracking device. Developed by Eigen (Grass Valley, Calif.), the Artemis tracking system was attached to the ultrasound probe and 3D images were reconstructed. All patients also underwent trans-rectal ultrasound prior to tracking and 47 had images co-registered with MRI.

Systematic 3D biopsy was successfully completed in 180 of 218 patients, though the success rate was closer to 95 percent among the last 50 patients, the authors noted. Biopsy took an average of 15 minutes with an additional 5 minutes required for MRI fusion and biopsy targeting.

The mean error—distance from the target to the center of the re-biopsy core—was measured at 1.2 mm. Error was found to be independent of prostate volume or biopsy location.

Targeted biopsies were more likely to reveal cancer than non-targeted biopsies. When highly suspicious areas were targeted, a 33 percent positive rate was demonstrated, compared with 7 percent for untargeted biopsies.

Overall, 30 men were diagnosed with prostate cancer, 9 using systematic biopsy only, 6 with MRI fusion-guided biopsy only and 16 using both protocols.

The authors added that after a “proper targeting technique” was established, 12 of the last 22 patients undergoing targeted biopsy were found to have prostate cancer. Three of these patients were diagnosed with systematic biopsy alone, four with targeted biopsy alone and five using both protocols.

The most common reasons for failure of 3D guidance included difficulties in positioning the tracking arm, software issues and poor patient compliance. The researchers converted to freehand biopsies in these cases.

“Use of 3D tracking and image fusion has the potential to transform MRI into a clinical tool to aid biopsy and improve current methods for diagnosis and follow-up of [prostate cancer],” Natarajan and co-authors stated. They cautioned, however, that, “While promising, these early experiences have not yet conclusively shown the benefit of tracking and targeted biopsy with MR fusion.”

View the article online

Article written by staff at healthimaging.com and adapted for the purposes of this newsletter.

Back To Top

Target Prophylaxis Shows Promise in Addressing post-TRUSP Infections

In men undergoing transrectal ultrasound-guided prostate biopsy (TRUSP), targeted antimicrobial prophylaxis based on findings from rectal swab cultures significantly reduces the incidence of infectious complications and has implications for decreasing the overall cost of care, according to data reported by researchers from Northwestern University, Chicago.

The effectiveness of targeted antimicrobial prophylaxis was evaluated in a study that included 451 men who underwent TRUSP between July 2010 and March 2011. Rectal swabs were obtained for culture and sensitivity testing from 117 patients at risk for colonization with fluoroquinolone-resistant organisms. Twenty-four of the 117 men (20.5%) had positive cultures for quinolone-resistant organisms and were treated with targeted antmicrobial prophylaxis based on the microbiological results. All 24 men were compliant with their targeted antimicrobial prophylaxis, which in the majority of cases involved an oral cephalosporin or trimethoprim-sulfamethoxazole (Bactrim, Septra DS).

The remaining subgroup of 334 men, which included those with and without risk factors for quinolone-resistant bacteria, received standard empiric prophylaxis comprised of a Fleet enema with two oral doses of ciprofloxacin (Cipro, Proquin XR), the first given 2 hours prior to TRUSP and the second 12 hours after the procedure.

Infectious complications after TRUSP were absent among the men who received targeted antimicrobial prophylaxis but developed in eight (2.4%) of the 334 patients who had empiric prophylaxis. Of the eight patients, seven had infections due to a quinolone-resistant pathogen, including one patient with sepsis, reported first author Aisha Taylor, MD, who worked on the study with Anthony Schaeffer, MD, and colleagues.

"Not only do we think targeted antimicrobial prophylaxis is an effective strategy to reduce infectious complications after TRUSP, but we believe this low-cost screening method can also significantly reduce cost of care. According to an analysis we conducted that included cost for the rectal swab and alternative antibiotic treatment using the most expensive intramuscular medication administered, the cost for treating 100 men undergoing TRUSP was calculated as $1,323 using the targeted approach versus $5,066 for empiric prophylaxis," Dr. Taylor said.

"Although rare, serious infectious complications after TRUSP are an important problem, and we believe the use of targeted antimicrobial prophylaxis using rectal swab cultures warrants further investigation in a larger, multi-institutional study," Dr. Taylor said

View the article online

Article written by staff at modernmedicine.com and adapted for the purposes of this newsletter.

Back To Top

Ultrasound Should be First-line approach for Pediatric Urinary Tract Infections

First-line renal ultrasound of febrile children with a first urinary tract infection (UTI) could provide data to obviate invasive voiding cystourethrography (VCUG), according to a study published in the Pediatric Infectious Disease Journal.

Belgian researchers conducted a prospective clinical and imaging study of 209 children (median age, 10 months) presenting with a clinically proven first UTI between July 2006 and July 2008 to evaluate multiple parameters including the diagnostic performance of renal ultrasound.

Experts have debated the utility of imaging studies for children with UTI, offered Khalid Ismaili, MD, PhD, from Hopital Universitaire des Enfants-Reine Fabiola in Brussels, Belgium, and colleagues. Up to 40 percent of children undergoing VCUG may have vesicoureteral reflex (VUR), and 60 to 80 percent of patients with VUR may have recurrent infection within 18 months of presentation, explained Ismaili et al.

However, physicians have not yet conclusively determined that VUR predisposes patients to UTI and renal scarring. Furthermore, renal scarring may occur in the absence of demonstrable reflux.

The standard of care at the author’s institution required an ultrasound during hospitalization and VCUG one month after the first UTI. The researchers used the imaging data to assess the diagnostic performance of renal ultrasound to detect VUR against the standard VCUG.

The 209 renal ultrasound studies did not show any structural abnormality in 81 percent of patients, offered Ismaili and colleagues. VCUG detected evidence of VUR in 25 percent of children, and 85 percent of these cases were classified as low-grade.

Thirty-four percent of patients with VUR on VCUG had an abnormal ultrasound, which the researchers attributed to ultrasound’s low sensitivity for low-grade reflux. They pointed out that ultrasound suggested abnormal pathology in 88 percent of patients with grade IV-V VUR.

Ismaili et al offered, “The overall performance of renal ultrasound as a diagnostic test to detect significant congenital abnormalities of the kidney and/or urinary tract excluding low-grade VUR was excellent; the sensitivity was 97 percent and specificity 94 percent.”

The researchers continued, “With a vast majority of children with UTI having a low risk of recurrence, as shown in our study, a major question is the extent to which these children are submitted to unnecessary and invasive investigations … [W]hen ultrasound examination was normal in children after a first UTI with fever, the risk of missing a significant renal abnormality was extremely low.”

Ismaili and colleagues said the recurrence rate among patients with low-grade VUR is similar to that of patients without VUR.

Ultimately, Ismaili and colleagues concluded, “Ultrasound should remain the first-line examination in febrile children with a first UTI. The presence or absence of abnormal ultrasound represents the key for deciding about VCUG studies.”

View the article online

Article written by staff at healthimaging.com and adapted for the purposes of this newsletter.

Back To Top

Ultrasound Fellowship Aims to Train Emergency Department Physicians

A program introduced in the emergency department (ED) at the Washington Hospital Center in Washington, DC, resulted in a 10-fold increase in the number of ultrasound scans performed by emergency medicine attending physicians who are not on the faculty of the ultrasound program at the teaching hospital, Elizabeth Pointius, MD, reported while presenting her findings here at the American Institute of Ultrasound in Medicine 2011 Annual Meeting.

"We're looking at this because emergency room ultrasound is a modality that is not always available 24 hours a day in every hospital," Dr. Pointius noted. Even at the busiest institutions there are times, particularly on weekend nights, when the technician is not available. "What you could be losing," she said, "is the ability to quickly diagnose something critical, like an ectopic pregnancy, for example."

The concern is based on the historical observation that many practicing emergency physicians were not trained in bedside ultrasound during their residency. If the staff sonographer is off-line, who do you turn to? she posited. To address this issue, the emergency medicine ultrasound fellowship program was initiated, and the current study is an analysis of that program's outcomes.

To perform the analysis, data were prospectively collected on bedside ultrasound scans performed by each attending ED physician at the Washington Hospital Center during a 4-year period. This is an institution that has more than 85,000 ED visits annually, and the activities of 39 of the 42 attending physicians were included.

Results showed that between 2006 and 2007, ED attending physicians performed a total of 744 bedside ultrasound scans. In 2008, 347 scans were performed. In 2009 — the first year of the ultrasound fellowship program — 4467 scans were performed by ED attending physicians, none of whom are faculty in the ultrasound program.

Dr. Pointius said she is thrilled with the results. "This way, you can not only obtain the image, you're also interpreting the image yourself. To have the history of the physical, and the ultrasound, you can put the whole picture together right there at the bedside and have the diagnosis. That's really useful."

Training the New Dogs and the Old

The efforts of Dr. Pointius in Washington, DC, are at the other end of the spectrum from those of Graciela Maldonado, MD, coordinator of ultrasound medical education at the University of California (UC) at Irvine School of Medicine. Rather than train physicians at the back end of their learning curve, she has developed the means to instill the value of ultrasound training from the beginning — during medical school.

In August 2010, UC Irvine School of Medicine instituted a heavy integration of bedside ultrasound into the first- and second-year medical student core curriculum.

"In the first year, the focus is on ultrasound basic anatomy and physiology. In the second year, the focus is on pathology — things that are relevant to second-year students who are training for their boards.” The idea is to keep the students interested by serving their immediate educational needs. As the program matures, the third-and fourth-year studies will address the uses of ultrasound within the various specialties, Dr. Maldonado explained.

By the time the UC Irvine graduates get to Dr. Maldonado's ED, sonography training will already be complete. "We've had ultrasound in our emergency medicine rotation for some years now," said Dr. Maldonado, "and we've had great feedback from students." For this group, if the ultrasound technician is nowhere to be found, the scan will still get done.

View the article online

Article written by staff at medscape.com and adapted for the purposes of this newsletter.

Back To Top