**7. Guiding liver resections**

IVb, V, and VI). Direct visualization and LIOUS should be used to compensate for the impossibility of liver palpation in laparoscopic surgery [75, 76]. In the case of laparoscopically treated malignant lesions, it is important to mark by IOUS imaging the oncological resection margins, this way ensuring their tracing by minimally invasive approach. Furthermore, the completion of the treatment is possible using ablative techniques (radiofrequency, microwave). The laparoscopic approach finds its indications especially for higher-risk cirrhotic patients (altered

**Figure 4.** Laparoscopic ultrasound guided radiofrequency ablation of HCC on cirrhotic liver (intraoperative aspect, from

With the evolution of technology and the experience of surgical teams, laparoscopic approaches to hepatectomies have become more and more used in centers of excellence. Several studies have shown that laparoscopic hepatectomy is a safe procedure and could have advantages over open surgery, translated by reduced blood loss and a shorter hospitalization stays [77, 78]. As for LIOUS, it should guarantee the same performance as the ultrasound used in conventional liver surgery. Although, LIOUS has been introduced since 1981, few studies have addressed this subject. Although reported to be a safe and accurate method [79], it is currently not routinely used in laparoscopic surgery [80], although the reliability of LIOUS in the staging of liver disease has been demonstrated to be similar to conventional IOUS [81]. Moreover, although many articles mention LIOUS as an important technique, few scientific

It has been demonstrated that making biopsies under IOUS guidance, laparoscopic or "classic," have a high diagnostic accuracy and are considered safe procedures with possible impact on surgical management [86, 87]. For example, liver metastases detected intra-operatively and confirmed by histopathological examination as having pancreatic origin could be a contrain-

In terms of non-excisional treatment of hepatic tumor formations, this can also be achieved by ablative techniques, such as ethanol injection [88], RFA (coagulation necrosis induced by high-frequency alternating currents-thermal energy) [89] and MWA (same as RFA, although

hepatic markers, clotting disorders) with subcapsular neoplastic lesions (**Figure 4**).

papers described this technique [82–85].

the personal archive of the authors).

80 Liver Research and Clinical Management

**6. Ultrasound-guided techniques**

dication for pancreatic radical surgery [58].

Localization of liver lesions is related to portal branches and suprahepatic veins, which are used to define segmental boundaries. Without the use of IOUS, it would probably be impossible to define correctly, anatomically, the hepatic segments and often the limits of the tumors, especially due to the existence of multiple anatomical variants [13].

Hepatic resections are known to be the standard treatment for malignant liver tumor formations, being the only procedure that provides oncological radicality [58]. Preservation of hepatic parenchyma should be a goal of the surgical team, especially in patients with cirrhotic liver, whose liver function and prognostic could be influenced by extensive resection. In these situations, IOUS plays an essential role because it allows the evaluation of the intrahepatic tumors, facilitating a limited but oncological liver resection. Thus, in modern hepatic surgery, whether HCC or colorectal liver metastases, the use of IOUS allows the realization of the so-called "radical but conservative surgery." Thus, obtaining continuous information on the relationship between liver lesions and intrahepatic bilio-vascular structures, the surgeon can guide his resection line, respecting the Glisson pedicles, and suprahepatic veins, with the ultimate goal of preserving as much functional hepatic parenchyma as possible [11, 12, 103, 104].

IOUS is also a real help for anatomical resections. This technique involves the compression of segmental portal branches between the transducer and the operator's fingers, resulting in a transient ischemia of the target parenchyma. This area can be marked with the electrocautery, and then the resection is made along the demarcation line [105–110].

Starting from the use of IOUS, Torzilli introduces new types of resection, such as mini-mesohepatectomy, for tumor formations located at the confluence of the cave vein with superhepatic veins [11, 12, 111]. These resections are based on the ultrasound study of the relationship between the tumor and the suprahepatic veins and the analysis of the blood flow at this level after clamping the proposed vein for resection. Evidence of an inverse flow in the peripheral portion of the compressed vein or of a collateral shunt between the clamped vein and the other superhepatic vein or cava vein will allow the ligation and segregation of the tumoraffected suprahepatic vein and the achievement of a limited resection, while maintaining the principles of oncological radicality [11, 12].

[121, 124–126], hepatic tumors [118, 127–130], edges of liver segments [117, 131–133], this being due both to ICG fluorescence [134], and to its property to be excreted into the bile [135]. Due to the property of being eliminated for more than 6 h after intravenous injection [126, 135], ICG-fluorescence imaging can also be used to identify small biliary fistulas after

Intraoperative Ultrasound of the Liver: Actual Status and Indications

http://dx.doi.org/10.5772/intechopen.73856

83

As for ICG-fluorescence imaging sensitivity in detecting liver metastases, it varies between 69 and 100%. However, sensitivity is limited because the examination does not have the ability to detect hepatic lesions at a depth greater than 8 mm in the hepatic parenchyma. It has also been shown that this method can detect new metastatic lesions in up to 43% of cases [137]. In fact, it has been reported that ICG-fluorescence imaging can detect superficial lesions of up to

Currently, a combination of a fluorophore, such as ICG, with an anti-tumor antibody is evaluated in preclinical studies. These new molecules could present a major advantage in the future for clinical applications that would allow the detection of tumor lesions with a higher TBR (tumor-to-background ratio between the intensity of fluorescence in tumor tissue and normal surrounding tissue). Recently, Harlaar et al. reported the first clinical trial using IRD-800CW-labeled bevacizumab for the detection of peritoneal metastases of colorectal

• For benign hepatic tumors, IOUS has the role to localize and to visualize the relationships

• For intraoperative interventional maneuvers (biopsies, ablative techniques), IOUS guid-

• In the case of HCC, CE-IOUS finds its usefulness especially in cirrhotic patients for the dif-

• CE-IOUS allows the surgeon to check areas where hepatic metastasis have been described

• IOUS is mandatory for anatomic resections and for limited but radical hepatectomy.

• In the case of HCC, IOUS is superior in detecting lesions measuring less than 1 cm.

ferential diagnosis between malignant lesions and regenerative nodules.

• IOUS is considered the "gold standard" in open surgery for colorectal cancer.

2 mm in both HCC and metastases liver disease due to colorectal cancers [127, 129].

• The IOUS has applications in both open or laparoscopic abdominal surgery.

hepatectomy [136].

origin [138].

**9. Key points**

with the intrahepatic structures.

ance is mandatory.

before chemotherapy.

**Acknowledgements**

Bartoș Adrian is the coordinator of this chapter.

Summarizing, the use of IOUS allows the extension of surgical indications for certain liver lesions that were either considered unresectable or required major surgery [104].
