Advances in hepatic resection and results for hepatocellular carcinoma

Preoperative hepatic vascular evaluation with CT and MR angiography: implications for surgery

Partial liver resection for living donor transplantations and treatment of hepatic tumors is a major surgical undertaking, and detailed knowledge of the hepatic angioarchitecture is essential to ensure safe and successful liver surgery. Noninvasive imaging techniques such as computed tomographic (CT) and magnetic resonance (MR) angiography have begun to replace conventional catheter angiography for evaluation of the hepatic vascular anatomy. Multisection CT angiography and MR angiography are complementary modalities that permit comprehensive, accurate preoperative delineation of the hepatic vascular anatomy and evaluation of the parenchyma in patients undergoing liver surgery, thereby obviating multiple invasive studies including catheter angiography. Understanding a surgeon's perspective on liver surgery is critical so that the required information can be provided accurately with imaging. Both CT angiography and MR angiography have had a significant impact on the selection of candidates for liver surgery as well as on surgical technique.

Dual-phase 3D MDCT angiography for evaluation of the liver before hepatic resection

OBJECTIVE

We sought to evaluate the accuracy of dual-phase MDCT angiography for assessing the liver before hepatic resection and to compare 2D and 3D images for quality and arterial branch visualization.

MATERIALS AND METHODS

Sixty-three patients with colorectal metastases (n = 30), hepatocellular carcinomas (n = 13), giant hemangiomas (n = 5), and other lesions (n = 15) underwent dual-phase MDCT using either a LightSpeed QX/i 4-MDCT (n = 31) or LightSpeed QX/i Ultra 8-MDCT (n = 32) scanner. Contrast material (150 mL of Isovue 370 [iopamidol]) was injected at a rate of 5 mL/sec. The arterial phase images were rendered on a workstation to obtain 3D MDCT angiograms that were assessed by two reviewers who were blinded to the surgical findings. Arterial anatomy was categorized according to the Michels classification. The reviewers assessed the 2D and 3D images for quality, arterial branch visualization, and differences between the 4- and 8-MDCT images. In the 43 patients who underwent resection, imaging findings were correlated with intraoperative findings.

RESULTS

The anatomy of hepatic arteries in the 63 patients was classified as follows: Michels type I, 51 patients (80.9%); type III, four patients (6.3%); type V, five patients (7.9%); and types VII, VIII, and IX, one patient (1.6%) each. In 40 (93%) of 43 patients, the surgical findings concurred with MDCT findings. Three discrepancies were due to failure to identify small accessory left hepatic arteries. Branch visualization and image quality of the 2D images were superior to those of the 3D images. No significant difference was found between the 4- and 8-MDCT images in branch visualization and image quality.

CONCLUSION

Three-dimensional MDCT angiography is accurate for classification of hepatic arterial anatomy before hepatic resection. Although 2D data sets show small arteries to better advantage than 3D MDCT angiograms, the 3D MDCT angiograms provide a useful overview of hepatic anatomy.

Multidetector-row computed tomography angiography for planning intra-arterial chemotherapy pump placement in patients with colorectal metastases to the liver

PURPOSE

The purpose of this study was to evaluate the use of multidetector computed tomography (MDCT) in the preoperative arterial evaluation of patients scheduled to undergo intra-arterial chemotherapy pump placement.

METHODS

Computed tomography scans of 30 patients with hepatic malignancies who were imaged with multiphase MDCT angiography for intra-arterial chemotherapy pump placement were retrospectively analyzed. Dual-phase helical CT was performed, and the arterial phase images were processed to depict the arterial anatomy and to identify pertinent anomalies. All findings were compared and correlated with surgical findings or catheter angiography if surgery was contraindicated.

RESULTS

Arterial anomalies identified on CT angiography in 20 of 30 patients included a replaced right hepatic artery (RHA; n = 6) or left hepatic artery (LHA; n = 8), a replaced common hepatic artery (n = 1), an accessory RHA (n = 2) or LHA (n = 6), a replaced gastroduodenal artery (GDA; n = 2), an extrahepatic connection between the accessory RHA and the replaced RHA (n = 1), and a common origin composed of the GDA and RHA and LHA (n = 2). There were no additional arteries or anomalies identified by catheter angiography, when available, or during surgery. Only 1 variant, an accessory hepatic artery, was not located during surgery. In 2 patients, the surgical team decided that pump placement was not feasible because of overly complex anatomy as determined by CT angiography. Computed tomography angiography showed an overall sensitivity of 100% and specificity of 97%.

CONCLUSIONS

Multidetector computed tomography angiography is accurate for the preoperative evaluation of normal and aberrant hepatic vasculature in patients under consideration for intra-arterial chemotherapy pump placement. Axial images alone permit recognition of vascular anomalies, including complex anatomy. Nevertheless, 3-dimensional rendering is useful to evaluate complex vascular anatomy and does not require catheter angiographic confirmation. In addition to aiding in selecting patients ideal for pump placement, MDCT permits noninvasive planning of their surgical approach.

Parenchymal transection with ultrasonic scalpel in liver resection

BACKGROUND

There is no ideal tool for parenchymal transection in liver resection and bleeding is still a major complication. The purpose of this study was to evaluate the usefulness of an ultrasonic scalpel and to describe our clinical experience in open liver resection.

METHODS

An ultrasonic scalpel was used in seven consecutive patients undergoing liver resection. During parenchymal transection coagulation shears were used with the power level set at 2 or 3, and the blunt blades were selected.

RESULTS

In each case, bleeding from the liver parenchyma was trivial, but haemostasis of large vessels required suture ligation. Postoperatively none of the patients experienced local technical complications such as haematoma, bile leak or infection.

DISCUSSION

Although complete haemostasis of large vessels cannot be achieved, the ultrasonic scalpel may be used for parenchymal transection in liver resection to reduce blood loss. Larger series of patients are needed before a definitive statement regarding the efficacy of this method can be made.

Using multidetector CT for preoperative vascular evaluation of liver neoplasms: technique and results

OBJECTIVE

The purpose of our study was to evaluate the performance of CT angiography using multidetector CT (MDCT) for preoperative vascular evaluation in candidates who were scheduled for liver neoplasm resection.

SUBJECTS AND METHODS

Forty-two consecutive subjects with malignant liver tumors scheduled for resection were studied with multiphase MDCT. The first 22 subjects underwent both multiphase MDCT angiography and catheter angiography before surgery. The subsequent 20 subjects underwent only preoperative CT angiography. Postprocessing was performed, and the images were analyzed for the depiction of arterial, portal vein, and hepatic vein anatomy and for the identification of important vascular variants. The postprocessing findings were compared and correlated with the findings from catheter angiography (22/42) or intraoperative sonography (42/42) and surgery (42/42).

RESULTS

Arterial anomalies were detected on the images of 17 of 42 patients, including a replaced right hepatic artery in five, replaced left hepatic artery in six, accessory right and left hepatic arteries in two, common trunk for the celiac and superior mesenteric arteries in one, and early bifurcation of the celiac artery in one. In 22 patients in whom catheter angiography confirmation was available, the number of arteries and almost all the significant anomalies were correctly identified on CT angiography (accuracy, 97%; sensitivity, 94%; specificity, 100%). In the subset of 20 patients who underwent MDCT angiography without catheter angiography confirmation, all clinically relevant information was provided by CT angiography. The portal and hepatic vein anatomy and the relationships of the liver tumors to the neighboring venous structures were shown on CT.

CONCLUSION

Multidetector CT provides valuable preoperative information about hepatic vascular architecture and can be used as a noninvasive alternative to catheter angiography before oncologic liver surgery.