ICUS Weekly News Monitor 4-17-2015

1.  Uro Today,  Apr 15, 2015,  Transabdominal contrast-enhanced ultrasound imaging of the prostate     Authors:  Mischi M, et al
 
2.  Academic Radiology,  Apr 13, 2015,  Contrast-Enhanced Subharmonic and Harmonic Ultrasound of Renal Masses Undergoing Percutaneous Cryoablation     Authors: John R. Eisenbrey, PhD
 
3.  Medscape Medical News,  Apr 2, 2015,  Portable Ultrasound to Improve Emergency and Critical Care     By Alicia Ault
 
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Uro Today
Ultrasound Med Biol. 2015 Apr;41(4):1112-8.
doi: 10.1016/j.ultrasmedbio.2014.10.014
Apr 15, 2015
 
Transabdominal contrast-enhanced ultrasound imaging of the prostate
Authors:  Mischi M, Demi L, Smeenge M, Kuenen MP, Postema AW, de la Rosette JJ, Wijkstra H
Electrical Engineering Department, Eindhoven University of Technology, Eindhoven, The Netherlands; Urology Department, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.  This email address is being protected from spambots. You need JavaScript enabled to view it.
 
Abstract
 
Numerous age-related pathologies affect the prostate gland, the most menacing of which is prostate cancer (PCa).
 
The diagnostic tools for prostate investigation are invasive, requiring biopsies when PCa is suspected. Novel dynamic contrast-enhanced ultrasound (DCE-US) imaging approaches have been proposed recently and appear promising for minimally invasive localization of PCa. Ultrasound imaging of the prostate is traditionally performed with a transrectal probe because the location of the prostate allows for high-resolution images using high-frequency transducers. However, DCE-US imaging requires lower frequencies to induce bubble resonance and, thus, improve contrast-to-tissue ratio. For this reason, in this study we investigate the feasibility of quantitative DCE-US imaging of the prostate via the abdomen. The study included 10 patients (age = 60.7 ± 5.7 y) referred for a needle biopsy study. After having given informed consent, patients underwent DCE-US with both transabdominal and transrectal probes. Time-intensity contrast curves were derived using both approaches and their model-fit quality was compared. Although further improvements are expected by optimization of the transabdominal settings, the results of transabdominal and transrectal DCE-US are closely comparable, confirming the feasibility of transabdominal DCE-US; transabdominal curve fitting revealed an average determination coefficient r2 = 0.91 (r2 > 0.75 for 78.6% of all prostate pixels) compared with r2 = 0.91 (r2 > 0.75 for 81.6% of all prostate pixels) by the transrectal approach. Replacing the transrectal approach with more acceptable transabdominal scanning for prostate investigation is feasible. This approach would improve patient comfort and represent a useful option for PCa localization and monitoring.
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Academic Radiology
DOI: http://dx.doi.org/10.1016/j.acra.2015.03.008
Apr 13, 2015
 
Contrast-Enhanced Subharmonic and Harmonic Ultrasound of Renal Masses Undergoing Percutaneous Cryoablation
 
Authors: John R. Eisenbrey, PhD correspondence email, Colette M. Shaw, MD,  Andrej Lyshchik, MD,  Priscilla Machado, MD,  Costas D. Lallas, MD,  Edouard J. Trabulsi, MD,   Daniel A. Merton, RDMS,   Traci B. Fox, EdD,   Ji-Bin Liu, MD,  
Daniel B. Brown, MD,   Flemming Forsberg, PhD
 
Abstract:
 
Rationale and Objectives
The objective of this study was to evaluate and compare contrast-enhanced subharmonic and harmonic ultrasound as tools for characterizing solid renal masses and monitoring their response to cryoablation therapy.
 
Materials and Methods
Sixteen patients undergoing percutaneous ablation of a renal mass provided informed consent to undergo ultrasound examinations the morning before and approximately 4 months after cryoablation. Ultrasound contrast parameters during pretreatment imaging were compared to biopsy results obtained during ablation (n = 13). Posttreatment changes were evaluated by a radiologist and compared to contrast-enhanced magnetic resonance imaging (MRI)/computed tomography (CT) follow-up.
 
Results
All masses initially showed heterogeneous enhancement with both subharmonic and harmonic ultrasound. Early contrast washout in the mass relative to the cortex was observed in 6 of 9 malignant and 0 of 4 benign lesions in subharmonic mode and 8 of 9 malignant and 1 of 4 benign lesions in harmonic imaging. In cases where the lesion was adequately visualized at follow-up (n = 12), subharmonic and harmonic ultrasound showed accuracies of 83% and 75%, respectively, in predicting treatment outcome. Although harmonic imaging showed less overall error, no significant differences (P > .29) in ablation cavity volumes were observed between MRI/CT and either contrast-imaging mode.
 
Conclusions
Subharmonic and harmonic contrast-enhanced ultrasound may be a safe and accurate imaging alternative for characterizing renal masses and evaluating their response to cryoablation therapy. Although subharmonic imaging was more accurate in detecting effective cryoablation, harmonic imaging was superior in quantifying ablation cavity volumes.
 
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Medscape Medical News
Apr 2, 2015
 
Portable Ultrasound to Improve Emergency and Critical Care (American Institute of Ultrasound in Medicine (AIUM) 2015 Annual Convention. Presented March 24, 2015)
By Alicia Ault
 
Ultrasound devices have shrunk to the point where they are now handheld and can be used in the emergency department or the critical care unit for easier triage, faster interventions for acute events, and better monitoring.
 
Delegates attending the American Institute of Ultrasound in Medicine 2015 Annual Convention in Lake Buena Vista, Florida, heard about quick bedside scans to detect bleeding after trauma, fractures, or torn tendons, and to assess fluid accumulation around the lungs, which could indicate congestive heart failure.
 
This could lead to earlier interventions, Larry Mo, PhD, from GE Global Research, told Medscape Medical News, but he acknowledged there are still technical and operational hurdles to overcome.
 
GE is looking for ways to reduce reliance on highly skilled sonographers, which is a barrier to the more widespread use of new ultrasound applications. There is a high degree of intra- and interuser variation with ultrasound. However, if a computer selects the planes and algorithms used to determine the border of a vessel wall, instead of a human being, for instance, consistency and quality will likely improve, Dr Mo explained.
 
In addition, analytics could make outcomes-related data points more easily understood. The development of 3D images might also reduce reliance on trained sonographers.
 
With a more user-friendly device, emergency medical technicians could conduct a scan in an ambulance or helicopter, for instance, and triage on the basis of a 3D image or forward the image or analytics data to the emergency department.
 
In Europe, emergency physicians are using CT less often in children who have suffered a traumatic injury; instead, they are using contrast-enhanced ultrasound, said Jason Castle, also from GE Global Research. Contrast agents are not approved for use in the United States, but there is great interest in not having to expose children to ionizing radiation, Castle told Medscape Medical News.
 
Patient Monitoring
 
Dr Mo also discussed the potential of critical care applications to add overall patient-monitoring information. For example, a GE project, supported by the National Heart, Lung, and Blood Institute, looked at whether ultrasound could be used to monitor the hemodynamic state, and perhaps give an early warning of internal bleeding.
 
The project is complete and animal studies have demonstrated utility, but "we can't predict when this product will be made available," Castle reported.
 
GE is also conducting a project, funded in part by the National Space Biomedical Research Institute, to determine whether 3D ophthalmic ultrasound can measure intracranial pressure as a surrogate for brain trauma or other abnormal conditions.
 
Being able to quickly measure intracranial pressure could be a life-saver, said session moderator Philip Levy, MD, from Goryeb Children's Hospital in Morristown, New Jersey, and St. Louis Children's Hospital.
 
Often, emergency physicians have to call in an ophthalmologist to make a diagnosis, which takes time. "We need to make a quick diagnosis in real-time," Dr Levy told Medscape Medical News.
 
The 3D picture being developed by GE will allow clinicians to see whether there is bleeding or edema and to quickly determine if the patient needs an emergency procedure, he explained.
 
Dr Mo and Mr Castle are employees of GE Global Research. Dr Levy has disclosed no relevant financial relationships.
 
American Institute of Ultrasound in Medicine (AIUM) 2015 Annual Convention. Presented March 24, 2015.

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