Detection of liver neoplasms: techniques and outcomes

MRI characteristics for the differential diagnosis of benign and malignant small solitary hypovascular hepatic nodules

PURPOSE

To compare the MRI findings of benign and malignant solitary hypovascular hepatic nodules and identify the differentiating features.

MATERIALS AND METHODS

A total of 135 patients with solitary hypovascular hepatic lesions up to 3 cm (mass forming intrahepatic cholangiocarcinoma, n=29; metastases, n=26; inflammatory pseudotumors and solitary necrotic nodule, n=48; and hemangioma, n=32) were assessed. MRI findings were analyzed, and lesions were scored for peripheral and intratumoral appearance and enhancement patterns.

RESULTS

Univariate and multivariate analyses showed that the most common findings for benign lesions were subcapsular, sharp margin, homogeneous, marked high signal on T2WI, mild hyperintensity on T2WI, increasing intensity of peripheral globular enhancement, and persistent central septum-like linear enhancement on delayed phase (P<0.05). An area under the curve of 0.955 was obtained for differentiating malignant from benign nodules using the combined imaging features of ill-defined margins, heterogeneity, decreasing intensity of peripheral rim-like enhancement, and central increasing intensity of patchy enhancement. Interobserver agreement was good, ranging from 0.72 to 1.00.

CONCLUSION

MRI may be a useful noninvasive method for determining whether hypovascular hepatic nodules are malignant or benign.

Ferucarbotran versus Gd-DTPA-enhanced MR imaging in the detection of focal hepatic lesions

AIM: To evaluate the efficacy of ferucarbotran-enhanced MR imaging in the detection of focal hepatic lesions compared to plain and Gd-DTPA-enhanced MR imaging.

METHODS: Fifty-nine patients with suspected focal hepatic lesions were admitted to the study. Plain MR imaging (FSE T₂WI with fat suppression and GRE T₁WI sequences) and Gd-DTPA dynamic enhanced MR of the liver were initially performed followed by ferucarbotran-enhanced MR imaging 48 h later (including GRE T₁WI, FSE T₂WI with fat suppression, and GRE T₂*WI sequences). Images were reviewed independently by three observers. Results were correlated with surgery and pathologic examination or reference examination, and sensitivity was statistically calculated for the different MR imaging sequences.

RESULTS: Among all confirmed lesions (n = 133), ferucarbotran-enhanced MR imaging revealed 130 lesions on FSE T₂WI with fat suppression, 115 lesions on dynamic T₁WI GRE, and 127 lesions on GRE T₂*WI. Pre-contrast MR imaging revealed only 84 lesions on GRE T₁WI and 106 lesions on FSE T₂WI with fat suppression, while Gd-DTPA dynamic enhanced GRE T₁WI revealed 123 lesions. For 44 micro-lesions (< 1.0 cm) in all patients the detection rates were as follows: ferucarbotran-enhanced FSE T₂WI with fat suppression, 93.2% (41/44); ferucarbotran-enhanced GRE T₂*WI, 88.6% (39/44); Gd-DTPA dynamic-enhanced GRE T₁WI, 79.5% (35/44); pre-contrast FSE T₂WI with fat suppression, 54.5% (24/44); and pre-contrast GRE T₁WI, 34.1% (15/44). In detecting micro-lesions, statistically significant difference was found for Ferucarbotran-enhanced FSE T₂WI with fat suppression and GRE T₂*WI sequences compared to the other sequences (P < 0.05).

CONCLUSION: Ferucarbotran-enhanced FSE T₂WI with fat suppression and GRE T₂*WI sequences are superior in detecting micro-lesions (< 1 cm) in comparison with plain and Gd-DTPA dynamic-enhanced MR imaging.

Detection of liver metastases: comparison of gadobenate dimeglumine-enhanced and ferumoxides-enhanced MR imaging examinations

PURPOSE

To compare gadobenate dimeglumine (Gd-BOPTA)-enhanced magnetic resonance (MR) imaging with ferumoxides-enhanced MR imaging for detection of liver metastases.

MATERIALS AND METHODS

Twenty consecutive patients known to have malignancy and suspected of having focal liver lesions at ultrasonography (US) underwent 1.0-T MR imaging with gradient-recalled-echo T1-weighted breath-hold sequences before, immediately after, and 60 minutes after Gd-BOPTA injection. Subsequently, MR imaging was performed with turbo spin-echo short inversion time inversion-recovery T2-weighted sequences before and 60 minutes after ferumoxides administration. All patients subsequently underwent intraoperative US within 15 days, and histopathologic analysis of their resected lesion-containing specimens was performed. Separate qualitative analyses were performed to assess lesion detection with each contrast agent. Quantitative analyses were performed by measuring signal-to-noise and contrast-to-noise ratios (CNRs) on pre- and postcontrast Gd-BOPTA and ferumoxides MR images. Statistical analyses were performed with Wilcoxon signed rank and Monte Carlo tests.

RESULTS

Sensitivity of ferumoxides-enhanced MR imaging was superior to that of Gd-BOPTA-enhanced MR imaging for liver metastasis detection (P <.05). Ferumoxides MR images depicted 36 (97%) of 37 metastases detected at intraoperative US, whereas Gd-BOPTA MR images depicted 30 (81%) metastases during delayed phase and 20 (54%) during dynamic phase. All six metastases identified only at ferumoxides-enhanced MR imaging were 5-10 mm in diameter. There was a significant increase in CNR between the lesion and liver before and after ferumoxides administration (from 3.8 to 6.8, P <.001) but not before or after Gd-BOPTA injection (from -4.8 to -5.5, P >.05).

CONCLUSION

Ferumoxides-enhanced MR imaging seems to be superior to Gd-BOPTA-enhanced MR imaging for liver metastasis detection.

Cystic changes in hepatic metastases from gastrointestinal stromal tumors (GISTs) treated with Gleevec (imatinib mesylate)

OBJECTIVE

The purpose of this article is to illustrate the CT findings in patients with hepatic metastases from a gastrointestinal stromal tumor who were treated with STI-571.

CONCLUSION

Hepatic metastases from gastrointestinal stromal tumors that respond to treatment with STI-571 can appear as near-cystic components with well-defined borders on contrast-enhanced CT. Most metastases became smaller. These metastases resemble simple cysts, but density measurements may differentiate them from one another.

Evaluation of the accuracy of gadobenate dimeglumine-enhanced MR imaging in the detection and characterization of focal liver lesions

OBJECTIVE

We evaluated the extent to which hepatic lesion characterization and detection is improved by using gadobenate dimeglumine for enhancement of MR images.

MATERIALS AND METHODS

Eighty-six patients were imaged before gadobenate dimeglumine administration, immediately after the 2 mL/sec bolus administration of a 0.05 mmol/kg dose (dynamic imaging), and at 60-120 min after the IV infusion at 10 mL/min of a further 0.05 nmol/kg dose (delayed imaging). The accuracy for lesion characterization was assessed for a total of 107 lesions. Sensitivity for lesion detection was assessed for a total of 149 lesions detected on either intra-operative sonography, iodized oil CT, CT during arterial portography, or follow-up contrast-enhanced CT as the gold standard.

RESULTS

The accuracy in differentiating benign from malignant liver lesions increased from 75% and 82% (the findings of two observers) on unenhanced images alone, to 89% and 80% on dynamic images alone (p<0.001, p = 0.8), and to 90.7% when combining the unenhanced and dynamic image sets (p<0.001, p = 0.023). Delayed images did not further improve accuracy (90% and 91%; p = 0.002, p< 0.05). A similar trend was apparent in terms of accuracy for specific diagnosis: values ranged from 49% and 62% on unenhanced images alone, to 76% and 70% on combined unenhanced and dynamic images (p<0.001, p = 0.06), and to 75% and 70% on inclusion of delayed images (p<0.001, p = 0.12). The sensitivity for lesion detection increased from 77% and 81% on unenhanced images alone, to 87% and 85% on combined unenhanced and dynamic images (p = 0.001, p = 0.267), and to 92% and 89% when all images were considered (p<0.001, p = 0.01).

CONCLUSION

Contrast-enhanced dynamic MR imaging with gadobenate dimeglumine significantly increases sensitivity and accuracy over unenhanced imaging for the characterization of focal hepatic lesions, and delayed MR imaging contributes to the improved detection of lesions.

Focal liver lesions: evaluation of the efficacy of gadobenate dimeglumine in MR imaging--a multicenter phase III clinical study

PURPOSE

To evaluate gadobenate dimeglumine (Gd-BOPTA) for dynamic and delayed magnetic resonance (MR) imaging of focal liver lesions.

MATERIALS AND METHODS

In 126 of 214 patients, MR imaging was performed before Gd-BOPTA administration, immediately after bolus administration of a 0.05- mmol/kg dose of Gd-BOPTA, and 60-120 minutes after an additional intravenously infused 0.05-mmol/kg dose. In 88 patients, imaging was performed before and 60-120 minutes after a single, intravenously infused 0.1-mmol/kg dose. T1- and T2-weighted spin-echo and T1-weighted gradient-echo images were acquired. On-site and blinded off-site reviewers prospectively evaluated all images. Intraoperative ultrasonography, computed tomography (CT) during arterial portography, and/or CT with iodized oil served as the reference methods in 110 patients.

RESULTS

Significantly more lesions were detected on combined pre- and postcontrast images compared with on precontrast images alone (P <. 01). All reviewers reported a decreased mean size of the smallest detected lesion and improved lesion conspicuity on postcontrast images. All on-site reviewers and two off-site reviewers reported increased overall diagnostic confidence (P <.01). Additional lesion characterization information was provided on up to 109 (59%) of 184 delayed images and for up to 50 (42%) of 118 patients in whom dynamic images were assessed. Gd-BOPTA would have helped change the diagnosis in 99 (47%) of 209 cases and affected patient treatment in 408 (23%) of 209 cases.

CONCLUSION

Gd-BOPTA increases liver lesion conspicuity and detectability and aids in the characterization of lesions.

Safety and pharmacokinetics of a new liposomal liver-specific contrast agent for CT: results of clinical testing in nonpatient volunteers

RATIONALE AND OBJECTIVES

To evaluate the safety and pharmacokinetics of BR21, a liposome-encapsulated iomeprol formulation, in nonpatient volunteers.

METHODS

This was a single-blind, placebo-controlled, ascending dose study in 30 adult, male nonpatient volunteers, randomized to receive a single intravenous bolus (2 mL/s) of BR21 (0.5, 1.0, 1.5, 2.0, and 2.5 mL/kg, four volunteers per dose level) or matched volumes of placebo (0.9% saline, 10 volunteers). The safety controls performed consisted of preand postdose complete physical examinations, measurement of vital signs, electrocardiographic controls, clinical laboratory investigations (hematology, serum chemistry, and urinalysis), and monitoring of adverse events. The safety controls and monitoring of subjects for adverse events continued up to 7 days after the dose. For pharmacokinetic analysis, the determination of total iomeprol content was performed by a high-performance liquid chromatography assay procedure in blood, urine, and fecal samples collected before the dose and serially after the dose, up to 120 hours.

RESULTS

No serious adverse events occurred throughout the study. All nonserious adverse events were minor and mild in intensity and rapidly resolved without treatment. No difference in the incidence of adverse events was observed among the various doses of BR21 and between BR21 and placebo. There were no clinically significant changes in vital signs, electrocardiographic parameters, or clinical laboratory findings. Iomeprol blood level decay can be described by a three-exponential function, consistent with a distribution phase (range, t1/2 0.12-0.21 hours), a fast elimination phase (range, t1/2 1.2-1.5 hours), and a slow elimination phase from a deep compartment (range, t1/2 3.3-4.5 hours). There was an apparent linearity in the relation between the area under the curve and the dose. Urinary elimination of unchanged iomeprol accounted for 89% to 90% of injected dose within 24 hours.

CONCLUSIONS

BR21 appeared to be safe and well tolerated in nonpatient subjects. Its pharmacokinetic profile was compatible with nonspecific distribution into the extracellular fluid space and specific distribution into a deep compartment.

Liver metastases: comparison of current MR techniques and spiral CT during arterial portography for detection in 20 surgically staged cases

PURPOSE

To compare spiral computed tomography during arterial portography (CTAP) with current magnetic resonance (MR) imaging, including hepatic arterial-dominant phase, gadolinium-enhanced, spoiled gradient-echo imaging, for the prospective detection of liver metastases in 20 patients who subsequently underwent surgery to confirm findings.

MATERIALS AND METHODS

Twenty patients underwent spiral CTAP and MR imaging within 1 week. Spiral CTAP and MR images were interpreted separately in blinded fashion. All patients subsequently had intraoperative confirmation. Sensitivity, specificity, and positive and negative predictive values were determined for lesion detection and segmental distribution.

RESULTS

CTAP and MR images demonstrated, respectively, 54 and 60 true-positive lesions, six and one false-positive lesions, 15 and 22 true-negative (i.e., benign) lesions, and eight and two false-negative lesions. CTAP and MR images demonstrated, respectively, 57 and 62 true-positive segmental involvements, six and one false-positive segmental involvements, 89 and 95 true-negative segmental involvements, and eight and two false-negative segmental involvements. No significant difference in lesion detection was observed.

CONCLUSION

Spiral CTAP and MR imaging were approximately equivalent for lesion detection in patients who were evaluated preoperatively for resection of liver metastases. The lower cost and fewer problems with artifacts may suggest that MR imaging is the preferred modality for preoperative assessment of patients for surgical treatment of liver metastases.

Safety, tolerance, biodistribution, and MR imaging enhancement of the liver with gadobenate dimeglumine: results of clinical pharmacologic and pilot imaging studies in nonpatient and patient volunteers

PURPOSE

The purpose of this study was to assess safety, tolerance, biodistribution, and magnetic resonance (MR) imaging enhancement of the liver with gadobenate dimeglumine.

MATERIALS AND METHODS

Phase I single-blind studies were performed in 53 healthy volunteers, of whom 39 received gadobenate dimeglumine and 14 placebo. Another 106 patients with focal liver disease received gadobenate dimeglumine in parallel-group, open-label, phase II studies. The imaging potential of gadobenate dimeglumine was assessed in all 106 patients plus 11 healthy volunteers, whereas pharmacokinetics were determined for 42 healthy volunteers. Safety was assessed for all subjects enrolled in the study. Imaging protocols for healthy volunteers were similar to those for patients and comprised predose T2-weighted sequences and pre- and postinjection T1-weighted spin-echo and gradient-echo sequences.

RESULTS

Gadobenate dimeglumine was safe and well tolerated in healthy volunteers and patients, with pharmacokinetics described adequately as a distribution phase and an elimination phase. Most of the injected dose of gadobenate was excreted unchanged in urine within 24 hours, although a fraction corresponding to 0.6%-4.0% of the injected dose was eliminated with the bile and recovered in the feces. The gadobenate dimeglumine-enhanced signal intensity of liver parenchyma was dose-related and constant for 120 minutes. Gadobenate dimeglumine-enhanced MR imaging was superior to nonenhanced MR imaging in more than 50% of patient studies, with more lesions seen in 26%-38% of patients and smaller lesions in 21%-33% of patients. In general, image sets acquired 40-180 minutes after administration of a dose were preferred, whereas images acquired during the dynamic phase after administration were typical of those obtained with extracellular fluid contrast agents.

CONCLUSION

Gadobenate dimeglumine is a safe and efficacious MR imaging contrast agent suitable for both delayed and dynamic imaging of the liver.

Soluble interleukin-2 receptor levels in hepatocellular cancer: a more sensitive marker than alfa fetoprotein

BACKGROUND

Worldwide, the majority of cases of hepatocellular cancer (HCC) arise in individuals with chronic hepatitis B or C virus infections. Early detection of HCC in these patients provides the best chance for curative treatment, but serum alfa fetoprotein (AFP) levels are frequently normal in patients with small HCCs. The purpose of this study was to determine: (1) whether soluble interleukin-2 receptor (sIL-2R) levels are elevated more frequently than AFP levels in HCC patients and (2) whether sIL-2R levels are useful as a marker of successful treatment and recurrence of disease.

PATIENTS AND METHODS

We are performing a prospective screening program with high-risk, chronic hepatitis virus-infected patients to detect HCC. Patients are screened by using abdominal ultrasonography, serum AFP measurements, and serum sIL-2R measurements. Normal serum sIL-2R levels were established using results from 174 healthy volunteers with no evidence of hepatitis virus infection or HCC.

RESULTS

HCC has been diagnosed in 99 patients from a cohort of 1520 screened patients. Serum AFP levels were elevated in 79 patients (80%), whereas sIL-2R levels were elevated in 98 of the 99 patients (99%, P < .01, chi2 test). For 27 of the 99 patients (27%), HCC was diagnosed at an early stage and complete resection or ablation was performed. Serum sIL-2R levels returned to normal in all 27 patients after treatment, whereas AFP levels remained slightly elevated in 5 of the 27 (18%). Among the 16 patients in this group of 27 who developed recurrent HCC, sIL-2R levels became elevated in all 16, whereas AFP levels were elevated at diagnosis of recurrence for only 10 (P < .05).

CONCLUSIONS

This study with chronic hepatitis B or C virus-infected patients indicates that (1) serum sIL-2R levels are abnormal in patients with HCC with a significantly greater frequency, compared with AFP levels, and (2) sIL-2R levels are a more sensitive marker of successful treatment and recurrence of HCC. Based on these findings, we now use serum sIL-2R measurements both to screen high-risk patients and to monitor treatment responses in patients with hepatitis who develop HCC.

Malignant liver lesions: comparison of spiral CT arterial portography and MR imaging for diagnostic accuracy, cost, and effect on patient management

We compared two imaging techniques, spiral CT arterial portography (CTAP) and MR imaging, for diagnostic accuracy, procedural cost, and effect on management of 26 patients referred for hepatic surgery for suspected limited malignant liver disease. CTAP and MR imaging were done within a 1-week period (19 within 24 hours); the results of the studies were interpreted prospectively by separate reviewers. Surgical data were evaluated in conjunction with imaging data in 10 patients. Lesion detection and segmental involvement were determined and sensitivity and specificity were calculated. Procedural cost was determined from hospital billing codes. Effect on patient management was determined by the referring oncologic surgeon. CTAP and MR imaging showed 185 and 176 true-positive malignant lesions, 15 and zero false-positive malignant lesions, zero and 18 true-negative malignant lesions, and 13 and 22 false-negative malignant lesions, respectively. CTAP and MR imaging showed 107 and 105 true-positive segments, 11 and zero false-positive segments, 80 and 91 true-negative segments, and four and six false-negative segments, respectively. There was a significant difference in specificity of segmental involvement between MR imaging (1.0 +/- 0) compared with CTAP (0.88 +/- 0.05), P = .03. Total procedural cost was $3,499 for CTAP and $1,224 for MR imaging. CTAP findings did not change patient management over MR imaging findings in any patient, whereas MR imaging findings resulted in a change in patient management over CTAP findings in seven patients (P = .015). The results of our study suggest that MR imaging has higher diagnostic accuracy and greater effect on patient management than CTAP does and is 64% less expensive.

Ex vivo MRI in extracorporeal liver surgery

Extracorporeal resection of hepatic tumors that were considered inoperable in the past is now possible in selected cases. Such procedures require high-quality preoperative images for the exact delineation of the tumor extent and for an optimal planning of the line of parenchymal division. In-vivo CT and MRI can not always depict the tumor adequately. In such cases, ex-vivo MRI may be a useful additional technique. It combines a high spatial resolution with the best possible soft tissue contrast, as was learned from previous studies on donor livers destined for transplantation. Ex-vivo MRI favours both a sufficiently radical resection as well as sufficient hepatic functional reserve to be present for reimplantation. A case history is reported together with details on the technical procedure.