Hepatic MR imaging using ferumoxides: prospective evaluation with surgical and intraoperative sonographic confirmation in 25 cases

Orthotopic liver transplantation in combination with neoadjuvant therapy: a new paradigm in the treatment of unresectable intrahepatic cholangiocarcinoma

PURPOSE OF REVIEW

Surgical resection is the primary modality of treatment for hilar and intrahepatic cholangiocarcinoma (HCCA-ICCA). For unresectable early-stage HCCA, excellent long-term tumor recurrence-free patient survival has been achieved using a strict regimen of preoperative staging and neoadjuvant chemoradiation treatment followed by orthotopic liver transplantation (OLT). However, in the case of unresectable ICCA, data on outcomes after OLT are limited. The present article reviews the current literature on the surgical treatment of ICCA focusing on the role of OLT in combination with neoadjuvant therapy and risk stratification of patients being considered for transplantation for unresectable ICCA.

RECENT FINDINGS

Numerous studies reported poor survival outcomes after OLT for ICCA. Recent data using a combination of neoadjuvant therapy followed by OLT in appropriately selected patients with unresectable ICCA demonstrated promising disease recurrence-free survival.

SUMMARY

Risk stratification for patient selection is crucial to optimize survival outcomes. Excellent long-term disease recurrence-free survival can be achieved in selected patients with unresectable ICCA using a combination of OLT and neoadjuvant therapy. Current data support the expansion of liver transplant criteria for treatment of unresectable ICCA.

[Malignant focal liver lesions]

Focal liver lesions are a very common occurrence. The detection and differentiation of such lesions is particularly important for the management of oncology patients and is a core task for radiology. The early and conclusive detection of malignant liver processes in a cost-efficient manner and with a low radiation dose for the patient requires systematic and skillful use of the various radiological methods. This review explains the application of current radiological methods for the detection and differentiation of malignant liver lesions and the typical appearance of the most commonly found liver malignancies.

Clinical diagnosis and staging of cholangiocarcinoma

Cholangiocarcinoma is the most frequent biliary malignancy. It is difficult to diagnose owing to its anatomic location, growth patterns and lack of definite diagnostic criteria. Currently, cholangiocarcinoma is classified into the following types according to its anatomic location along the biliary tree: intrahepatic, perihilar or distal extrahepatic cholangiocarcinoma. These cholangiocarcinoma types differ in their biological behavior and management. The appropriate stratification of patients with regard to the anatomic location and stage of cholangiocarcinoma is a key determinate in their management. Staging systems can guide this stratification and provide prognostic information. In addition, staging systems are essential in order to compare and contrast the outcomes of different therapeutic approaches. A number of staging systems exist for cholangiocarcinoma-several early ones have been updated, and new ones are being developed. We discuss the emerging diagnostic criteria as well as the different staging systems for cholangiocarcinoma, and provide a critical appraisal regarding these advances in biliary tract malignancies.

Current surgical management of hilar and intrahepatic cholangiocarcinoma: the role of resection and orthotopic liver transplantation

Cholangiocarcinoma (CCA) is a rare but devastating malignancy that presents late, is notoriously difficult to diagnose, and is associated with a high mortality. Surgical resection is the only chance for cure or long-term survival. The treatment of CCA has remained challenging because of the lack of effective adjuvant therapy, aggressive nature of the disease, and critical location of the tumor in close proximity to vital structures such as the hepatic artery and the portal vein. Moreover, the operative approach is dictated by the location of the tumor and the presence of underlying liver disease. During the past 4 decades, the operative management of CCA has evolved from a treatment modality that primarily aimed at palliation to curative intent with an aggressive surgical approach to R0 resection and total hepatectomy followed by orthotopic liver transplantation.

Cholangiocarcinoma

Cholangiocarcinoma is a primary hepatic malignancy originating from bile duct epithelium. It is the second most common primary hepatic neoplasia, and its incidence has increased within the last 3 decades. Although several risk factors have been identified, especially chronic biliary tract inflammation, most patients with cholangiocarcinoma have no identifiable risk factors. Recent developments in radiologic and molecular diagnostic methods have helped in the diagnosis of this disease. The only curative therapy is surgical resection or liver transplantation. For patients with advanced stage disease, survival remains limited. With growing understanding of the molecular and cellular etiology of this disease, new targeted therapies are being developed.

The role of contrast-enhanced ultrasound for focal liver lesion detection: an overview

The development of new ultrasound (US) contrast agents and sonographic techniques has considerably improved the possibilities of ultrasound in the assessment of liver tumors. An overview is given on diagnostic potential of contrast-enhanced US (CEUS) and real-time low mechanical index technique in the detection of various focal liver lesions compared with computed tomography, magnetic resonance imaging or intraoperative US. In two of our own studies that included 100 patients each we showed an increase of correct findings in CEUS compared with B-mode US from 64% to 87% and from 67% to 84% as confirmed by intraoperative evaluation of the liver. Especially after chemotherapy and in the case of small metastases, significantly more metastases were correctly detected by CEUS compared with B-mode US. These results and clinical study results in the literature show that CEUS allows tumor detection and direct visualization of the tumor vascularity and put contrast-enhanced sonography among recommended noninvasive imaging methods for focal liver lesions with improvements in diagnostic strategy.

Efficacy and safety of MR imaging with liver-specific contrast agent: U.S. multicenter phase III study

PURPOSE

To assess prospectively the efficacy and safety of postcontrast magnetic resonance (MR) imaging with gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) compared with that of precontrast MR imaging in patients who are known to have or are suspected of having liver lesions and who are scheduled for hepatic surgery.

MATERIALS AND METHODS

Investigational review board approval and written informed consent were obtained. HIPAA went into effect after data collection. A total of 172 patients were enrolled. After precontrast MR imaging, 169 patients (94 men, 75 women; mean age, 61 years; age range, 19-84 years) received an intravenous bolus of 25 micromol/kg Gd-EOB-DTPA and underwent dynamic gradient-recalled-echo and delayed MR imaging 20 minutes after injection. Arterial and portal phase computed tomography (CT) were performed within 6 weeks of MR imaging. The standard of reference was surgery with intraoperative ultrasonography (US) and biopsy and/or pathologic evaluation of resected liver segments and/or 3-month follow-up of nonresected segments if intraoperative US was not available. Three blinded reviewers and unblinded site investigators identified liver lesions on segment maps. The Wilcoxon signed rank test was used to compare differences in per-patient sensitivity of precontrast and postcontrast MR images. Adverse events were recorded, and patient monitoring and laboratory assay were performed at time of injection and up to 24 hours after contrast material administration.

RESULTS

At MR imaging, 316 lesions were identified in 131 patients. In 77% (P = .012), 72% (P = .15), and 71% (P = .027) of patients for readers 1, 2, and 3, respectively, more lesions were seen at precontrast and postcontrast MR imaging combined than at precontrast MR imaging alone. Sensitivity values for blinded readings were significantly greater at postcontrast MR imaging than at precontrast MR imaging for two of three blinded readers. For all blinded readers, combined precontrast and postcontrast MR images showed no difference in sensitivity compared with helical CT scans. The use of MR imaging, however, yielded fewer patients with at least one false-positive lesion (37%, 31%, and 34% of patients for readers 1, 2, and 3, respectively) than did helical CT (45%, 36%, and 43% of patients for readers 1, 2, and 3, respectively).

CONCLUSION

Compared with precontrast MR imaging, postcontrast MR imaging with Gd-EOB-DTPA demonstrated improved sensitivity for lesion detection in the majority of blinded readers, with no substantial adverse events.

Preoperative assessment of focal liver lesions: multidetector computed tomography challenges magnetic resonance imaging

PURPOSE

To investigate prospectively multidetector computed tomography (CT) (MDCT) and magnetic resonance (MR) imaging (MRI) in the preoperative assessment of focal liver lesions.

MATERIAL AND METHODS

Multiphasic MDCT and conventional gadolinium-enhanced MRI were performed on 31 consecutive patients prior to hepatic surgery. All images were blindly analyzed as consensus reading. Lesion counts and their relation to vascular structures and possible extrahepatic disease were determined. The data from the MDCT and MRI were compared with the results obtained by intraoperative ultrasound (IOUS) and palpation. Histopathologic verification was available.

RESULTS

At surgery, IOUS and palpation revealed 45 solid liver lesions. From these, preoperative MDCT detected 43 (96%) and MRI 35 (78%) deposits. MDCT performed statistically better than MRI in lesion detection (P=0.008). Assessment of lesion vascular proximity was correctly determined by MDCT in 98% of patients and by MRI in 87%. Statistical difference was found (P=0.002). IOUS and palpation changed the preoperative surgical plan as a result of extrahepatic disease in 8/31 (26%) cases. In MDCT as well in MRI extrahepatic involvement was suspected in two cases.

CONCLUSION

MDCT was superior to MRI and nearly equal to IOUS in liver lesion detection and in the determination of lesion vascular proximity. However, both techniques fail to reliably detect extrahepatic disease.

Quantitative analysis of focal masses at MR imaging: a plea for standardization

PURPOSE

To assess the effects of changing analytic method variables on the signal intensity (SI) difference-to-noise ratios (SDNRs) for the contrast between lesions and background organs depicted on magnetic resonance (MR) images and to propose a standardized analytic method for the quantitative analysis of focal masses seen at MR imaging.

MATERIALS AND METHODS

The SIs of 48 liver metastases (originating from colorectal cancer) in 20 patients, the surrounding liver parenchyma, and the background noise were measured on T2-weighted MR images. All 2000 and 2001 issues of the American Journal of Roentgenology, the Journal of Magnetic Resonance Imaging, Magnetic Resonance Imaging, and Radiology were searched for articles describing quantitative analyses. SDNRs were calculated by using formulas from these articles and various region-of-interest (ROI) locations to measure metastasis and background noise SIs. The Wilcoxon signed rank test was used to compare the various SDNR calculations.

RESULTS

In 34 articles in which quantitative analyses of focal masses are described, the reported SDNRs were calculated with four different formulas. The SDNRs for our study material calculated with the four formulas reported in the literature differed grossly in both number and unit. The SDNRs for ROIs encompassing the entire metastasis differed significantly (P =.034) from the SDNRs for ROIs in a homogeneous area of the metastasis margin. Differences in SDNRs between various noise ROI locations were significant (P <.022).

CONCLUSION

Slight changes in the variables of quantitative analysis of focal masses had marked effects on reported SDNRs. To overcome these effects, the use of a standardized method involving one formula, a lesion ROI in a homogeneous area at the metastasis margin, and a background noise ROI along the phase-encoding axis in the air (including systematic noise) is proposed for the quantitative analysis of findings on magnitude MR images.

Comparison of dynamic gadolinium-enhanced and ferumoxides-enhanced MRI of the liver on high- and low-field scanners

PURPOSE

To compare the performance of dynamic gadolinium-enhanced and ferumoxides-enhanced MRI in the detection and characterization of hepatic lesions, on 1.5-T and 0.2-T magnets

MATERIALS AND METHODS

In 41 patients (23 men, 18 women), 52 hepatic MR examinations were performed and retrospectively analyzed; 39 and 13 examinations were performed on 1.5-T and 0.2-T magnets, respectively. A total of 33 of 41 patients had known malignancies, and 31 of 33 patients had biopsy of at least one lesion. First, a combination of unenhanced T2-weighted sequences and gradient-echo T1-weighted sequences were performed. Then, dynamic gadolinium-enhanced (0.1 mmol/kg) T1 GRE sequences were obtained, followed by intravenous drip infusion of ferumoxides (10 micromol/kg). The T2-weighted sequences were then repeated. The unenhanced and gadolinium-enhanced images (the Gd set) were reviewed separately from the unenhanced and ferumoxides-enhanced images (the ferumoxides set) by two abdominal imagers. The reviewers were blinded to clinical history and reviewed the individual studies in each set randomly. Each detected lesion was scored on a five-point scale for characterization scores: nonsolid (1 or 2), indeterminate (3), or solid (4 or 5). A consensus review was then performed correlating all available pathology, imaging, clinical findings, and follow-up to act as a gold standard. Receiver-operating-characteristic (ROC) curves were generated and both area-under-the-curve (Az values) and sensitivity values were calculated. Significance of Az and sensitivity differences was assessed using standard Z-test and chi-square.

RESULTS

Of 270 lesions detected by consensus, 211 were on 1.5-T and 59 were on 0.2-T scanners. The accuracy (Az values) of lesion detection overall, of both readers, was greater for the ferumoxides set than for the Gd set (reader 1: 0.95 vs. 0.89 (P < 0.05); reader 2: 0.91 vs. 0.78 (P < 0.05)). Az values for both readers were greater on the ferumoxides set for both the 1.5-T scans and the 0.2-T scans. Out of 270 lesions detected, 231 were characterized by consensus review as solid (185) or nonsolid (46). There was a significant improvement in lesion characterization for both readers on the GD set compared with the ferumoxides set on both high and low field scanners (Az reader 1: 0.99 vs. 0.96 (P < 0.05); Az reader 2: 0.99 vs. 0.95 (P < 0.05)), respectively.

CONCLUSION

At both 1.5-T and 0.2-T, ferumoxides-enhanced sequences were better for lesion detection, while gadolinium-enhanced sequences were better for lesion characterization, respectively.

Hepatic MR imaging with ferumoxides: multicenter study of safety and effectiveness of direct injection protocol

PURPOSE

To compare the safety and effectiveness of an undiluted direct injection of ferumoxides with those of a diluted slow infusion of ferumoxides during 30 minutes in patients with known liver lesions or in those suspected of having them.

MATERIALS AND METHODS

Two hundred thirty-three patients at 16 institutions were randomized to receive either an undiluted direct injection of 0.56 mg of iron per kilogram of body weight of ferumoxides administered during 2 minutes (2 mL/min) or a diluted slow infusion administered during 30 minutes. Safety was assessed with monitoring for adverse events and laboratory tests. For sensitivity, specificity, and accuracy analysis, two independent blinded observers identified and classified lesions as benign or malignant with precontrast images and with pre- and postcontrast images combined.

RESULTS

There was no statistically significant difference in adverse events in the group with direct injection compared with those in the group with infusion (21 [18%] of 114 patients vs 19 [17%] of 112 patients, respectively). No serious adverse events were observed. The most common adverse events in the group with direct injection versus the group with infusion were headache (five [4%] of 114 vs three [3%] of 112, respectively) and back pain (five [4%] of 114 vs three [3%] of 112, respectively). Overall, in 68 (62%) of 109 patients with direct injection and 71 (66%) of 108 patients with infusion, additional magnetic resonance (MR) imaging information was obtained after ferumoxides administration (P =.67). Sensitivity, specificity, and accuracy for the diagnosis of malignancy were significantly improved by adding images obtained after ferumoxides administration to the images obtained before contrast agent administration (P <.05 for all comparisons).

CONCLUSION

Direct injection of ferumoxides has safety and effectiveness profiles similar to those of slow infusion of the agent. Further findings indicate that the addition of ferumoxides increases the sensitivity and specificity of hepatic MR evaluation when compared with unenhanced MR imaging.