0
We're unable to sign you in at this time. Please try again in a few minutes.
Retry
We were able to sign you in, but your subscription(s) could not be found. Please try again in a few minutes.
Retry
There may be a problem with your account. Please contact the AMA Service Center to resolve this issue.
Contact the AMA Service Center:
Telephone: 1 (800) 262-2350 or 1 (312) 670-7827  *   Email: subscriptions@jamanetwork.com
Error Message ......
ARTICLE |

Ultrasonographic Characterization of Hepatic Cryolesions:  An Ex Vivo Study

C. M. Lam, MB,BS; S. M. Shimi, MB,ChB; A. Cuschieri, MD
Arch Surg. 1995;130(10):1068-1072. doi:10.1001/archsurg.1995.01430100046010.
Text Size: A A A
Published online

Objective:  To determine the physical basis for the ultrasonographic characteristics of the hepatic ice ball produced by cryotherapy and the size correlation between the actual hepatic ice ball and the ultrasonographic cryolesion.

Design:  Experimental ex vivo study involving controlled freezing with liquid nitrogen recirculating probes of fresh porcine livers immersed in various solutions at ambient temperatures (20.2°C to 22.6°C), together with measurements of the impedance of frozen and unfrozen liver.

Results:  First, the hyperechoic rim is caused by reflection of 34% of ultrasound waves at the interface between unfrozen and frozen liver as a consequence of an increased acoustic impedance of frozen liver that was calculated to be approximately 3.8 times that of unfrozen liver tissue. The increased acoustic impedance is due to the decrease in elasticity of hepatic tissue as it freezes. Second, the posterior acoustic shadowing is partly due to the attenuation of the incident ultrasound waves by reflection at the interface between unfrozen and frozen liver. It is also dependent on the crystalloid-protein content of hepatic parenchyma, which ensures a homogeneous lesion by preventing "shattering" within the cryolesion. This is in sharp contrast to the ultrasonographic appearance of an ice ball formed in ionized water, in which the hyperechoic rim overlies an area of posterior acoustic enhancement. Third, the correlation of the size between the ultrasonographic cyrolesion and the measured hepatic ice ball approached unity (r=.99), and the two measurements were identical for cryolesions less than 50 mm in diameter.

Conclusion:  Ultrasound is an accurate method for depicting the actual diameter of frozen solid hepatic tissue in cryotherapy for liver tumors, but the present technology does not provide accurate assessments of the volume of frozen tissue.(Arch Surg. 1995;130:1068-1072)

Topics

Sign in

Create a free personal account to sign up for alerts, share articles, and more.

Purchase Options

• Buy this article
• Subscribe to the journal

Figures

Tables

References

Correspondence

CME
Meets CME requirements for:
Browse CME for all U.S. States
Accreditation Information
The American Medical Association is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians. The AMA designates this journal-based CME activity for a maximum of 1 AMA PRA Category 1 CreditTM per course. Physicians should claim only the credit commensurate with the extent of their participation in the activity. Physicians who complete the CME course and score at least 80% correct on the quiz are eligible for AMA PRA Category 1 CreditTM.
Note: You must get at least of the answers correct to pass this quiz.
You have not filled in all the answers to complete this quiz
The following questions were not answered:
Sorry, you have unsuccessfully completed this CME quiz with a score of
The following questions were not answered correctly:
Commitment to Change (optional):
Indicate what change(s) you will implement in your practice, if any, based on this CME course.
Your quiz results:
The filled radio buttons indicate your responses. The preferred responses are highlighted
For CME Course: A Proposed Model for Initial Assessment and Management of Acute Heart Failure Syndromes
Indicate what changes(s) you will implement in your practice, if any, based on this CME course.
Submit a Comment

Multimedia

Some tools below are only available to our subscribers or users with an online account.

Sign in

Create a free personal account to sign up for alerts, share articles, and more.

Purchase Options

• Buy this article
• Subscribe to the journal

Related Content

Customize your page view by dragging & repositioning the boxes below.

Jobs
brightcove.createExperiences();