Renate Hammerstingl

Liver tumor characterization: Comparison between liver-specific gadoxetic acid disodium-enhanced MRI and biphasic CT - A multicenter trial

Objective: In our multi center trial we compared the potentials of biphasic contrast-enhanced computed tomography (CT) and a novel tissue-specific magnetic resonance imaging (MRI) contrast agent gadoxetic acid disodium in liver lesion characterization. Methods: A total of 176 patients with 252 liver lesions were analyzed. There were 104 malignant and 148 benign lesions. High-field strength (1.0 T or 1.5 T) MR systems with T1-and T2-weighted sequences were used with and without fat suppression. After gadoxetic acid disodium injection, dynamic imaging and hepatocyte phase MR imaging were performed. Biphasic with 150 mg I/kg of body weight (100-200 mL) spiral CT was also performed. Image reading consisted of on-site (by study investigators) and fully blinded off-site (by E.S.P; C.R; and A.S) evaluations. The classification (benign or malignant) and characterization (lesion type) outcomes of both techniques were assessed. All imaging results were verified against a standard of reference. Results: Both on-site and off-site evaluations demonstrated increases in the lesion classification accuracy with gadoxetic acid disodium-enhanced MRI when compared with spiral CT. This improvement was also shown for characterization. Gadoxetic acid disodium was well tolerated. Conclusions: Gadoxetic acid disodium offers a safe and diagnostically powerful tool for the evaluation of patients with focal liver lesions with a reliable assessment of lesion classification and characterization.

Preoperative evaluation of malignant liver tumors: comparison of unenhanced and SPIO (Resovist)-enhanced MR imaging with biphasic CTAP and intraoperative US.

Abstract. The purpose of this study was to evaluate the diagnostic efficacy of iron-oxide-enhanced MRI vs CT during arterial portography (CTAP) and intraoperative ultrasound (IOUS) in detection of liver neoplasms. Seventeen patients with malignant focal liver lesions (liver metastases, n=7), hepatocellular carcinomas (HCC, n=9), and cholangiocellular carcinoma (CCC, n=1) underwent presurgical Resovist-enhanced MRI and CTAP. Two independent observers (A and B) assessed the blinded images of unenhanced and iron-oxide-enhanced MRI vs CTAP for the presence, number, and location of the liver lesions. These results were compared lesion by lesion and segment by segment with the results of intraoperative ultrasound (n=17) serving as the reference standard. Eighty lesions were detected by intraoperative ultrasound in 17 patients. In comparison with IOUS (lesion-by-lesion analysis) the sensitivity was 86.8% for CTAP, 65% for combined unenhanced MR imaging, and 86.8% for combined Resovist-enhanced MRI as well as 86.8% for the combination of unenhanced and Resovist-enhanced MRI. Compared with the sensitivity of combined unenhanced MRI the sensitivity of CTAP as well as the sensitivity of combined Resovist-enhanced MRI was significantly higher (p<0.05). False-positive results were much higher in CTAP as compared with combined unenhanced and SPIO-enhanced MRI. Using the segment-by-segment analysis the specificity of combined unenhanced MRI with 100% (96.7–100%) as well as combined Resovist-enhanced MRI with 100% (96.7–100%) was significantly higher (p<0.05) in comparison with the specificity of CTAP with 91.1% (83.2–96.1%). The accuracy of combined unenhanced MRI was 100% (93.2–100%), combined Resovist-enhanced MRI 100% (93.6–100%) and of CTAP 85.2% (72.9–93.4%). In the detection of focal liver lesions iron-oxide-enhanced MR imaging is superior to unenhanced MRI and similar to CTAP.

Repeated Transarterial Chemoembolization in the Treatment of Liver Metastases of Colorectal Cancer: Prospective Study

PURPOSE To evaluate local tumor control and survival data after transarterial chemoembolization with different drug combinations in the palliative treatment of liver metastases in patients with colorectal cancer. MATERIALS AND METHODS The study was approved by institutional review board, and informed consent was obtained from all patients included in the study. A total of 463 patients (mean age, 62.5 years; range, 34.7-88.1 years) with unresectable liver metastases of colorectal cancer that did not respond to systemic chemotherapy were repeatedly treated with chemoembolization in 4-week intervals. In total, 2441 chemoembolization procedures were performed (mean, 5.3 sessions per patient). Of 463 patients, 67.4% had multiple (five or more) metastases, 8% had one metastasis, 10.4% had two metastases, and 14.3% had three or four metastases. The local chemotherapy protocol consisted of mitomycin C alone (n = 243), mitomycin C with gemcitabine (n = 153), or mitomycin C with irinotecan (n = 67). Embolization was performed with lipiodol and starch microspheres for vessel occlusion. Tumor response was evaluated with magnetic resonance imaging. The change in tumor size was calculated and the response was evaluated according to the Response Evaluation Criteria in Solid Tumors. Survival rates from first diagnosis and from first chemoembolization session were calculated according to the Kaplan-Meier method. Follow-up imaging was performed until patient death. RESULTS Evaluation of local tumor control resulted in partial response (68 patients [14.7%]), stable disease (223 patients [48.2%]), and progressive disease (172 patients [37.1%]). The 1-year survival rate after chemoembolization was 62%, and the 2-year survival rate was 28%. Median survival from date of diagnosis of liver metastases was 38 months and from the start of chemoembolization treatment was 14 months. There was no statistically significant difference between the three treatment protocols. CONCLUSION Chemoembolization is a minimally invasive therapy option for palliative treatment of liver metastases in patients with colorectal cancer, with similar results among three chemoembolization protocols.

Magnetic resonance imaging of focal liver lesions. Comparison of the superparamagnetic iron oxide resovist versus gadolinium-DTPA in the same patient

RATIONALE AND OBJECTIVES The authors assess the efficacy of static and dynamic magnetic resonance (MR) imaging using the superparamagnetic iron oxide SHU-555A (Resovist) versus standard dose of gadolinium (Gd)-DTPA in patients with focal liver lesions. METHODS Magnetic resonance imaging was performed in 30 patients suffering from histopathologically verified malignant (n = 22) and benign (n = 8) liver lesions. T2-weighted conventional and fat-suppressed as well as T1-weighted sequences were used before, during, and after fast intravenous administration of Resovist (1 mL/minute) at three doses of 4, 8, and 16 mumol/kg body weight. One week before the Resovist-enhanced MR imaging study 20 patients underwent Gd-DTPA-enhanced MR imaging. RESULTS Detection rate was improved for metastatic lesions revealing 36 lesions unenhanced versus 53 focal lesions using Resovist-enhanced MR imaging. Gadolinium-DTPA-enhanced scans showed no additional lesion versus unenhanced and Resovist-enhanced MR imaging. Static and dynamic imaging demonstrated no measurable percentage signal intensity loss (PSIL) using Resovist-enhanced MR imaging versus a percentage enhancement of 79.7% in Gd-DTPA enhanced scans. In the dynamic T2-weighted sequences, hepatocellular carcinoma nodules (n = 4) showed a rapid decrease in signal intensity starting at 44 seconds. Postinfusion of Resovist followed by a low, constant increase in signal intensity. Gadolinium-DTPA enhanced scans showed a percentage enhancement of 73.4 focal nodular hyperplasia (FNH) and hemangioma revealed a strong and early dose-dependent PSIL 44 to 60 seconds postinfusion with a prolonged signal loss for the FNH in the late study. Statistical evaluation revealed a statistically significant superiority of Resovist-enhanced MR imaging concerning the detection and delineation of focal liver lesions compared with unenhanced and Gd-DTPA enhanced scans (P < 0.05). CONCLUSIONS The fast infusion of the new superparamagnetic contrast agent Resovist shows advantages for dynamic and static MR imaging of focal liver lesions.

MR-compatible Assistance System for Biopsy in a High-Field-Strength System: Initial Results in Patients with Suspicious Prostate Lesions

PURPOSE To examine the feasibility and safety of magnetic resonance (MR)-guided biopsy by using a transgluteal approach in patients with suspicious prostate lesions by using an MR-compatible robotic system and a 1.5-T MR system. MATERIALS AND METHODS The study was approved by the institutional review board of University Frankfurt, and informed consent was obtained from each patient. A total of 20 patients (age range, 57.8-71.9 years; mean age, 65.1 years) underwent biopsy in a closed-bore high-field-strength MR system. Biopsy was performed with an MR-compatible pneumatically driven robotic system. T1-weighted gradient-echo fast low-angle shot and T2-weighted true fast imaging with steady-state precession sequences were used to plan and guide the intervention with a transgluteal access on the external planning computer of the assistance system. The system calculated the trajectory and then moved the guiding arm to the insertion point. The cannula was advanced manually, and biopsies were performed with the coaxial technique by using a 15-gauge pencil tip needle. Intervention time, complications, and biopsy findings were documented. RESULTS The MR-compatible robotic system did not interfere with image quality, nor did MR imaging cause dysfunction of the robot. In one patient, the interventionist caused a fail-safe system shutdown. This was due to inadvertent displacement of the guiding arm during cannula insertion. This problem was solved by increasing the displacement threshold. Accurate coaxial cannula biopsy could be performed in all subsequent patients. Sufficient histopathologic assessment was performed in 19 patients. Insufficient material was retrieved in the patient who experienced fail-safe system shutdown. The median intervention time was 39 minutes (23-65 minutes). No procedure-related complications were observed. CONCLUSION Preliminary results indicate that MR-guided robot-assisted biopsy is feasible and can be performed safely with highly accurate cannula placement.

Enhancement of liver parenchyma after injection of hepatocyte-specific MRI contrast media: a comparison of gadoxetic acid and gadobenate dimeglumine

To compare enhancement of liver parenchyma in MR imaging after injection of hepatocyte‐specific contrast media.

Assessment of liver fibrosis and steatosis in PBC with FibroScan, MRI, MR-spectroscopy, and serum markers.

Background In recent years noninvasive methods have been evaluated for the assessment of liver fibrosis predominantly in patients with viral hepatitis. In this study, transient elastography (FibroScan), magnetic resonance imaging (MRI), magnetic resonance (MR)-spectroscopy, and serum markers were compared in patients with primary biliary cirrhosis (PBC) for the assessment of liver fibrosis and steatosis. Methods Forty-five patients with PBC and histologic assessment of liver fibrosis received transient elastography and examinations for serum markers of fibrosis and steatosis. In addition, 41 out of 45 patients received contrast-enhanced MRI and 38 out of 45 patients received proton MR-spectroscopy. Results The adjusted accuracy (area under the receiver operating characteristic) for the diagnosis of histologic-stage ≥II for FibroScan, MRI-contrast enhancement and Forns index was 80%, 83%, and 69%, and for the diagnosis of liver cirrhosis 95%, 91%, and 94%, respectively. No correlation of histologic-stage was observed for FibroTest and AST to platelet ratio index. Histologic steatosis significantly correlated with body mass index (r=0.46), the SteatoTest (r=0.39), homeostasis model assessment of insulin resistance (r=0.46), and MR-spectroscopy (r=−0.76). The accuracy for the diagnosis of histologic steatosis was best with MR-spectroscopy (88%). Conclusions Contrast-enhanced MRI and FibroScan can be used with comparable results for the assessment of liver fibrosis in patients with PBC and seem to supplement each other. MR-spectroscopy represents the best method for highly accurate noninvasive measurement of liver steatosis.

Liver Metastases of Neuroendocrine Tumors: Treatment With Hepatic Transarterial Chemotherapy Using Two Therapeutic Protocols

OBJECTIVE The objective of our study was to retrospectively determine the effectiveness of hepatic transarterial chemotherapy using two therapeutic protocols-mitomycin C alone and combined mitomycin C and gemcitabine-on local tumor control and survival rate in patients with liver metastases from neuroendocrine tumors. MATERIALS AND METHODS This article describes a retrospective study of 48 patients (age range, 37-77 years; mean age, 61.1 years; SD, 10.3) with liver metastases from neuroendocrine tumors who underwent repetitive selective hepatic artery chemotherapy using mitomycin C alone (group 1, n = 18 patients who underwent 182 therapeutic sessions; mean, 10.11 sessions per patient) and combined mitomycin C and gemcitabine chemotherapy agents (group 2, n = 30 patients who underwent 312 therapeutic sessions; mean, 10.4 sessions per patient) with 4-week intervals between treatment sessions. RESULTS Both treatment protocols were well tolerated by all patients. Only minor side effects occurred in both groups, and no major complications developed. Local tumor control evaluation according to the Response Evaluation Criteria in Solid Tumors (RECIST) revealed the following for group 1: partial response, 11.1%; stable disease, 50%; and progressive disease, 38.9%. RECIST criteria for group 2 indicated partial response in 23.33%, stable disease in 53.34%, and progressive disease in 23.33%. The survival rate from the initial diagnosis to the fifth year for group 1 was 11.11% and for group 2, 46.67%. The median survival time from the initial diagnosis of group 1 was 38.67 months, whereas in group 2 it was 57.1 months. CONCLUSION Transarterial hepatic chemotherapy using mitomycin C and gemcitabine can be an effective therapeutic protocol for controlling local metastases and improving survival time in patients with hepatic metastases from neuroendocrine tumors.

Comparison of 1.0 M gadobutrol and 0.5 M gadopentetate dimeglumine-enhanced magnetic resonance imaging in five hundred seventy-two patients with known or suspected liver lesions: results of a multicenter, double-blind, interindividual, randomized clinical phase-III trial

Objective:To evaluate the diagnostic efficacy (accuracy, sensitivity, specificity) of 1.0 M gadobutrol versus 0.5 M gadopentetate for the classification of lesions as either benign or malignant in patients with known or suspected liver lesions. Methods and Materials:A multicenter, phase-III, randomized, interindividually controlled comparison study with blinded reader evaluation was performed to investigate the diagnostic efficacy of a bolus injection of 1.0 M gadobutrol compared with 0.5 M gadopentetate at a dose of 0.1 mmol Gd/kg BW. The imaging protocol included a dynamic 3D-evaluation, static conventional, and fat saturated T1-weighted sequences. MR datasets were evaluated by 3 independent radiologists. The standard of reference was defined by an independent truth panel (radiologist or hepatologist). The safety evaluation included adverse events, vital signs, and physical examination. Results:A total of 497 of 572 patients were eligible for the final efficacy analysis. Noninferiority of gadobutrol-enhanced magnetic resonance imaging (MRI) for the classification of liver lesions was demonstrated on the basis of diagnostic accuracy determined by the on-site investigators (−0.098, 0.021) as well as for the average reader of the blinded evaluation (−0.096, 0.014) (95% confidence interval), compared with the predefined standard of reference. Very similar increases in sensitivity (ranging from ∼10% to ∼55%) and specificity (ranging from ∼1%–∼18%) compared with precontrast MRI were also observed for the 2 contrast agent groups, with maximum differences of 4%.Very similar, low rates of adverse events were recorded for each of the 2 groups. No clinically relevant changes in vital signs or the results of the physical examination were observed in any patient. Conclusion:This study documents evidence for the noninferiority of a single i.v. bolus injection of 1.0 M gadobutrol (0.1 mmol/kg body weight) to 0.5 M gadopentetate (0.1 mmol/kg body weight) in the diagnostic assessment of liver lesions with contrast-enhanced MRI. The known excellent safety profile of gadobutrol was confirmed in this clinical trial and is similar to that of gadopentetate.

Does secretin-stimulated MRCP predict exocrine pancreatic insufficiency?: A comparison with noninvasive exocrine pancreatic function tests.

Background Data on magnetic resonance cholangiopancreatography with secretin stimulation (S-MRCP) for the assessment of exocrine pancreatic insufficiency (EPI) are limited. We compared pancreatic function tests with the findings of S-MRCP in patients with chronic pancreatitis (CP) and disease controls. Methods S-MRCP was performed in 23 patients (18 CP, 5 disease controls). MRCP images were analyzed for secretin-induced duodenal liquid filling (0=no filling; 1=duodenal bulb; 2=up to lower flexure; 3=beyond lower flexure). EPI was evaluated by fecal elastase, fecal fat concentration, and a 13C mixed chain triglyceride breath test. Clinically relevant EPI was stated if 2 of 3 tests were pathologic. Results EPI was diagnosed in 10 of 18 patients with CP. Patients without EPI showed either grade 2 (n=4) or grade 3 (n=9) duodenal filling, whereas only 1/10 patients with EPI showed grade 3 duodenal filling. Sensitivity and specificity of S-MRCP for the diagnosis of EPI were 69% and 90%, respectively. Conclusions Assessment of duodenal filling should be performed in patients who undergo S-MRCP for the evaluation of pancreatic morphology. However, minor degrees of duodenal filling are equivocal and require further diagnostic evaluation.