Transcript 04.Intern Seminar_JR..

Intraoperative US of the Liver:
Techniques and Clinical Applications
Intern 盧佳文
2006-09-21
Outline
Introduction
Applications of Intraoperative US of the Liver
Clinical Role of Intraoperative US
Introduction
Transducer Requirements
Transducer Sterilization
Technique for US of the Liver
Relevant Intraoperative Anatomy
Artifact
Transducer Requirements
5-MHz side-fire T-shaped
linear- or curvilineararray
transducer
– fit comfortably against the
palm of the hand and
between the fingers
– have color Doppler flow
and pulsed Doppler
– provide good near-field
resolution
Transducer Sterilization
Sterile condom sheaths
– most commonly
– The sheath must be long (typically about 1.5 m)
– fit snugly around the transducer to avoid artifacts
Low-temperature hydrogen peroxide gas plasma
sterilization techniques
– an entire sterilization cycle in 2–3 hours,
– safe to use with heat-sensitive equipment,
– enable the use of a sterile transducer without a condom sheath
Glutaraldehyde or dialdehyde solution
Ethylene oxide gas sterilization with high-temperature
eratio
Technique for US of the Liver
Basic setting
Technique
– in a transverse
position, starting at the
most lateral margin of
the left lateral segment
II and extending
toward the right side
Technique
– bathing the field with sterile saline for very near lesion
Relevant Intraoperative Anatomy
Hepatic vein
– the transducer is held in a transverse midline
position and angled toward the beating heart
Portal vein
– Placing the transducer on the undersurface of
the liver, over segment IV, and angling the
transducer toward the porta hepatis
Relevant Intraoperative Anatomy
Specific arteries
– a replaced right hepatic
artery that arises from the
superior mesenteric artery
and courses posterior to
the portal vein
– replaced or accessory left
hepatic artery that arises
from the left gastric artery
and courses through the
ligamentum venosum
Artifact
The cut margin of a liver segment is often
echogenic because of small amounts of gas that
enter the parenchyma and sinusoids
– after cautery or sonication
– Should D/D with mucinous colorectal cancer
metastases
Acoustic shadowing produced by palpation of
the posterior liver surface
Applications of Intraoperative US of the Liver
Survey for Primary or Metastatic Lesions
Lesion Characterization
Guidance for Tumor Resection and Metastasectomy
Evaluation of Vessel Patency
Liver Transplantation
Tumor Ablation
Biliary Disease
Extrahepatic Disease
Survey for Primary or Metastatic Lesions
Resolution:
– larger than 2 mm
Sensitivity:
– more than 90%
of 25%–35% more
lesions than does
preoperative imaging
Lesion Characterization
Hemangioma
–
–
–
–
Varied appearance
Palpation
Doppler
Vessel involvement
Lesion Characterization
Metastasis
– Bull’s-eye or target
sign
Colon cancer
Carcinoid tumors
FNH
sarcoma
Lesion Characterization
Benign and malignant
tumors frequently
coexist
Guidance for Tumor Resection and
Metastasectomy
the presence or absence of vascular
occlusion or invasion
margins of 1–2 cm are required for
adequate lesion resection
Guidance for Tumor Resection and
Metastasectomy
Evaluation of Vessel Patency
Benign
– displacement and
effacement of vessels
Malignant
– invasion and occlusion
of vessels
Evaluation of Vessel Patency
a tumor-associated thrombus:
– avascular
a tumor thrombus :
– an arterial waveform at
pulsed Doppler evaluation
Clinical Role of Intraoperative US
Schmidt et al showed a sensitivity and specificity
of 98% of 95%, respectively, for detection of colorectal
cancer metastases
intraoperative US still provided additional useful
information in 50% of their patients, and this information
resulted in a change in the surgical procedure in 15%
40% of the lesions demonstrated by intraoperative US
were neither visible nor palpable at surgery