Uptake of mangafodipir trisodium in liver metastases from endocrine tumors

The purpose of the study was to investigate retrospectively whether mangafodipir trisodium (MnDPDP) can enhance the liver metastases from endocrine tumors. Thirteen patients with endocrine tumors and liver metastases underwent T1-weighted spin-echo (SE) and turbo gradient-echo (GRE) MRI conducted before and 20 to 60 minutes after iv infusion of MnDPDP. Additional 24-hour-delay scans were performed in 8 of 13 patients. MR signal intensity (SI) was measured in liver parenchyma and metastases, which was then related to that of paraspinal muscle. A total of 30 lesions on precontrast and postcontrast images and 18 lesions on 24-hour-delay images were measured. An enhancement by 49% in SE and 40% in GRE images (P = .0001) was observed in tumor tissues after MnDPDP infusion. In 24-hour-delay images, the SI of the lesions remained relatively high, but in liver parenchyma, it decreased significantly, and the tumor-liver tissue contrast was reduced.     

Contrast-enhanced MRI of the liver with mangafodipir trisodium: imaging technique and results

Magnetic resonance (MR) contrast agents are now routinely used for detecting and characterizing focal liver lesions. Liver specific, hepatobiliary, MRI contrast agent mangafodipir trisodium (Mn-DPDP) is taken up by the functioning hepatocytes and excreted by the biliary system. Contrast uptake leads to persistent elevation of T1-weighted signal of normal liver parenchyma within 10 minutes of injection. Most tumors of non-hepatocellular origin typically are hypointense relative to enhanced liver parenchyma on T1 weighted images and are more conspicuous than on unenhanced images. Whereas, tumors of hepatocellular origin such as focal nodular hyperplasia (FNH), adenoma, and well-differentiated hepatocellular carcinomas (HCC) have been shown to accumulate Mn-DPDP, providing characterization information to discriminate hepatocellular from non-hepatocellular tumors. The purpose of this pictorial essay is to illustrate the appearance of various liver tumors on mangafodipir enhanced liver MR imaging.     

MRI with mangafodipir trisodium in the detection of pancreatic tumours: comparison with helical CT

The aim was to compare spiral CT and MRI enhanced with mangafodipir trisodium (Mn-DPDP) in the detection and staging of pancreatic lesions. 20 patients with suspected pancreatic cancer were included in a phase III study. Triphasic spiral CT (4 ml s-1) and MRI (axial T1 weighted turbo spin echo with and without fat suppression, T1 weighted gradient echo and T2 weighted turbo spin echo at 1.5 T) were performed. All sequences were repeated following contrast medium using the same instrument settings as in the unenhanced sequences. Mn-DPDP was administered by slow injection of 5 mumol kg-1 body weight. Imaging results were correlated with surgery, laparoscopy, biopsy and/or follow-up. Eight pancreatic adenocarcinomas were present. Ten patients had chronic pancreatitis, and two showed a stenosing papillitis. CT detected eight malignant lesions and MRI detected seven. One pancreatic cancer was not detected with MRI. CT and MRI excluded malignancy in nine patients. MRI and CT returned three false positive results. Mn-DPDP improved delineation of the lesion, resulting in a higher level of diagnostic confidence. Differentiation between pseudotumorous lesions in chronic pancreatitis and pancreatic carcinoma was difficult due to similar slight contrast enhancement. Owing to better delineation of the lesion and the higher confidence in diagnosis, MRI with Mn-DPDP may have the potential to improve the detection rate and the staging accuracy of focal pancreatic lesions. These results need to be confirmed in a larger patient trial.     

MRI with mangafodipir trisodium in the detection and staging of pancreatic cancer

The purpose of this study was to compare prospectively computed tomography (CT) and magnetic resonance (MR) imaging before and after mangafodipir trisodium infusion for the detection and staging of focal pancreatic lesions. From November 1996 to October 1997, 43 consecutive patients suspected to have a focal pancreatic lesion were included in a phase III study. Triphasic helical CT was performed, as well as MRI at 1.5 T, as follows: axial T1-weighted (T1w) turbo spin echo (TSE), spectral presaturation with inversion recovery (SPIR) T1w TSE, T1w turbo field echo (TFE), and SPIR T2w TSE before and after mangafodipir trisodium (0.01 mmol/ml, 0.5 ml/kg) infusion. Imaging results were correlated with surgery, laparoscopy, laparoscopic ultrasound, and biopsy. Objective measurements were performed by measuring signal intensities (SIs) of lesion and parenchyma and calculating contrast indexes (CIs) and contrast-to-noise-ratios (CNRs) to assess the delineation of the tumor. SIs were correlated with four phantom standards with a known SI. Thirty-eight pancreatic adenocarcinomas were present, as well as one cystadenoma, two papillomas, and two cases of focal pancreatitis. SI measurements revealed significant increases in CIs for the lesion compared with the parenchyma in T1w TSE (69.7 vs 152.7; P = 0. 0003) and T1w TFE (107.8 vs 194.2; P = 0.0002). These series also revealed significant increases in CNRs (for T1w TSE: 9.7 vs 13.0; P = 0.0407 and for T1w TFE: 14.5 vs 26.1; P = 0.0001). In the other series, there was no significant increase. CT detected 38 lesions, MRI without mangafodipir trisodium detected 39 lesions, and MRI with mangafodipir trisodium detected 40 lesions, giving detection accuracy rates of 88%, 91%, and 93%, respectively. Staging accuracy rates for vascular ingrowth were 81%, 75%, and 81%, respectively. Overall staging accuracy rates were 57%, 54%, and 54%, respectively, mostly due to undetected small metastases in the peritoneum, omentum, or liver (< 1 cm). This study indicates that a) MRI after mangafodipir trisodium gives a better delineation of the tumor in T1w series, but b) does not significantly improve the detection rate and staging accuracy of focal pancreatic lesions over MRI without this contrast medium.     

Diagnostic accuracy and agreement between whole-body diffusion MRI and bone scintigraphy in detecting bone metastases

Purpose

This study was done to determine the diagnostic value of whole-body magnetic resonance using diffusion-weighted imaging with background suppression (WB-DWIBS) for detecting bone metastases compared with whole-body bone scintigraphy (WB-BS).

Materials and methods

Twenty-three patients with solid tumours underwent both WB-DWIBS imaging and WBBS. A nuclear medicine specialist interpreted WB-BS images and two blinded radiologists, first independently and then jointly, interpreted the WB-DWIBS images by completing a reading grid categorising the skeletal segments. Cohen’s k statistic was used to determine interobserver agreement in reading the WB-DWIBS images and the agreement between WB-BS and WB-DWIBS. Sensitivity and specificity were calculated per patient and per lesion.

Results

Interobserver agreement in reading the WBDWIBS images was substantial or good, with κ=0.68. Analysis of agreement between the nuclear physician’s and the radiologists’ readings provided κ=0.87 [95% confidence interval (CI)=0.76–0.98)] Per-lesion analysis gave a sensitivity of 80% (95% CI=75–85) and a specificity of 98.2% (95% CI=96.5–99.8).

Conclusions

We found a good level of interobserver agreement for the WB-DWIBS images and an excellent level of agreement in the subjective judgement of presence or absence of disease between WB-BS and WB-DWIBS after consensual double reading. WB-DWIBS has the same specificity as WB-BS in detecting bone metastases. The anatomical sites exhibiting the highest level of disagreement between WB-DWIBS and WB-BS are the pelvis, the coccyx, and the sternum, all sites at which detection with WB-BS has the greatest limitations.     

Small colorectal liver metastases: Detection with SPIO-enhanced MRI in comparison with gadobenate dimeglumine-enhanced MRI and CT imaging

The aim of this prospective study was to compare the diagnostic role of superparamagnetic iron oxide (SPIO)-enhanced liver magnetic resonance imaging (MRI) versus gadobenate dimeglumine (GbD)-enhanced MRI and computed tomography (CT) investigations for detection of small (less than 1 cm) colorectal liver metastases (LMs) of colorectal cancer. Seventy-eight LMs in 16 patients were evaluated with dynamic CT imaging, GbD-enhanced dynamic MR imaging and SPIO-enhanced MR imaging. Two radiologists were reviewed the LMs seperately. Agreement between the readers and three algorithms was analyzed. Differences between the lesion detection ratios of the methods were analyzed by two proportion z test. Sensitivity values of each modality were also calculated. Interobserver agreement values with kappa analysis were found to be the best for three modalities and kappa values were 0.866, 0.843, and 1.0 respectively. For all 78 LMs, SPIO-enhanced MRI detected all lesions (100% sensitivity). This sensitivity value was higher than GbD-enhanced MRI, and there was a significant difference (p < 0.05). GbD-enhanced MRI depicted 71 lesions and this modality could not detected 7 lesions (91% sensitivity). This modality had moderate sensitivity, and this value is greater than CT imaging, so there was a significant difference also (p < 0.05). Dynamic triphasic CT imaging detected 64 (R1) and 65 (R2) LMs. This modality had the lowest sensitivity (R1: 0.82, R2: 0.83 respectively). Only SPIO-enhanced MRI was able to detect all LMs less than 1 cm. LMs were the best detected with SPIO-enhanced MRI. We recommend SPIO-enhanced MRI to be the primary alternative modality especially for diagnosis of small colorectal LMs.     

Functioning acinar cell pancreatic carcinoma: diagnosis on mangafodipir trisodium (Mn-DPDP)-enhanced MRI.

We describe the imaging findings of a functional pancreatic acinar cell carcinoma in a patient who presented with weight loss, hyperlipasemia, and multiple foci of subcutaneous fat necrosis. The tumor invaded the adjacent splenic and portal vein, causing isolated left-sided portal hypertension. At MRI, the tumor showed marked enhancement following administration of the hepatobiliary-specific contrast agent mangafodipir trisodium (Mn-DPDP), thereby demonstrating the functional nature of the tumor. Avid uptake of Mn-DPDP by a functioning pancreatic tumor has not been reported in the radiology literature.     

Intra-arterial treatment of liver metastases from colorectal carcinoma

Colorectal carcinoma is a major public health concern with its yearly mondial incidence of about one million cases and yearly mortality of 500,000 cases. The liver is the organ most frequently affected by metastases with a frequency of 40 to 60% (contemporaneous in 25% of cases). While surgical resection is the only curative therapy, many patients are not such candidates due to the infiltrative nature of the liver metastases. Systemic chemotherapy and biotherapy regimens are the conventional treatment options for patients with multiple liver metastases. Under such circumstances, intra-arterial therapy may play a major role. We will review the main types of endovascular therapies for liver metastases from colorectal carcinoma including indications, results and potential complications.     

MRI and PET/CT of patients with bone metastases from breast carcinoma

3.0Tesla magnetic resonance imaging (MRI) with diffusion-weighted imaging (DWI) was compared with combined 18F-fluorodeoxyglucose positron emission tomography and computed tomography (PET/CT) in patients with suspected bone metastases from breast cancer. A prospective clinical study was performed in 13 female breast cancer patients (mean age 61years; range 45-85 years). The spine was imaged in the sagittal plane with T1-weighted (T1), short tau inversion recovery (STIR), and T2-weighted fat-saturated (T2) sequences. The pelvis was imaged similarly in the coronal plane. Axial DWI was performed from the skull base to the mid-thigh. MRI and PET/CT were performed in all patients at a maximum interval of 10 working days and at least 14 days after chemotherapy. MRI was reviewed by two radiologists, and their consensus on potential metastases in 27 predefined locations was recorded. The predefined locations were the vertebral bodies (24), the left (1) and right (1) pelvic bones, and the sacral bone (1). The PET/CT was reviewed by a radiologists and a nuclear medicine physician. MRI detected 59 of the 60 active metastases found with our gold standard modality PET/CT. T1 had the highest sensitivity (98%) but rather low specificity (77%), but with the addition of STIR and DWI, the specificity increased to 95%. The additional metastases detected with MRI most likely represented postherapeutic residual scars without active tumour. In conclusion, 3.0Tesla MRI with T1, STIR, and DWI is useful for the clinical evaluation of bone metastases from breast cancer and compares well to PET/CT.     

Liver metastases from colorectal carcinoma: detection with continuous CT angiography.

A diagnostic approach to assess liver metastases from colorectal carcinoma was prospectively evaluated in 30 patients with and without metastases on the basis of findings at conventional computed tomography (CT). With the technique, termed continuous CT angiography (CCTA), CT data were continuously sampled for 24 seconds at the same section level after initiation of a 3-second injection of 10-20 mL of contrast medium in the common hepatic artery. The procedure was repeated for each contiguous section level of the liver. Findings at preoperative ultrasound (US), conventional CT, and CCTA were compared with those at intraoperative US and surgical exploration as the standard of reference. Forty-four liver metastases were identified in 16 patients, and 14 patients had no metastases. CCTA had a sensitivity of 98% (43 lesions identified) and higher accuracy (81% [54 of 67 diagnoses]) than US and conventional CT. The data indicate that CCTA can supplement information obtained with conventional imaging techniques in patients who must undergo hepatic surgery because of metastases from colorectal carcinoma.     

Detection of liver metastases from adenocarcinoma of the colon and pancreas: comparison of mangafodipir trisodium-enhanced liver MRI and whole-body FDG PET

OBJECTIVE: The objective of our study was to assess the relative performance of mangafodipir trisodium-enhanced liver MRI and whole-body FDG PET for the detection of liver metastases from adenocarcinoma of the colon and pancreas. MATERIALS AND METHODS: Imaging data of 34 patients (23 men, 11 women; age range, 44-78 years) with adenocarcinoma of the colon (n = 27) or adenocarcinoma of the pancreas (n = 7) who had undergone mangafodipir trisodium-enhanced liver MRI and whole-body FDG PET were retrospectively reviewed for the presence and number of liver metastases. Histopathology (n = 25) or follow-up imaging (n = 9) served as the standard of reference. Breath-hold T1-weighted gradient-recalled echo, respiratory-triggered T2-weighted fast spin-echo, and mangafodipir trisodium-enhanced axial fat-saturated high-spatial-resolution (256 x 512) T1-weighted gradient-recalled echo images were obtained on a 1.5-T scanner. FDG PET was performed after the injection of 15-20 mCi (555-740 MBq) of FDG. The sensitivity, positive predictive value, and accuracy were calculated for each technique. The performances of the two techniques were compared using the Fisher's exact test. RESULTS: Thirty patients had hepatic metastases and four had no hepatic metastases according to the standard of reference. The total number of metastases was 79, including 33 that measured less than 1 cm. Based on a per-patient analysis, MRI and FDG PET showed sensitivities of 96.6% and 93.3%, positive predictive values of 100% and 90.3%, and accuracies of 97.1% and 85.3%, respectively. According to a per-lesion analysis, MRI and FDG PET showed sensitivities of 81.4% and 67.0%, positive predictive values of 89.8% and 81.3%, and accuracies of 75.5% and 64.1%, respectively. MRI detected more hepatic metastases than FDG PET (p = 0.016). Of the 33 subcentimeter lesions confirmed on the standard of reference, all were identified on MRI, whereas only 12 were detected on FDG PET (p = 0.0001). CONCLUSION: In patients with colon and pancreatic adenocarcinoma, high-spatial-resolution mangafodipir trisodium-enhanced liver MRI and whole-body FDG PET were comparable in the detection of patients with liver metastases. FDG PET provided additional information about extrahepatic disease and was useful in initial staging. However, significantly more and smaller liver metastases were detected on MRI than on FDG PET.     

Sequence optimization in mangafodipir trisodium-enhanced liver and pancreas MRI

To find an optimal magnetic resonance (MR) sequence for mangafodipir trisodium-enhanced liver and pancreas imaging, six healthy volunteers were studied using a 1.5 T MR system with different T1-weighted abdominal imaging sequences. These were turbo field (gradient)-echo (TFE), fast field (gradient)-echo (FFE), and spin-echo sequences before and after mangafodipir trisodium administration. Various parameter combinations were investigated within each sequence type, and then the best combination was found and compared with those of the other sequences. Signal intensity (SI) measurements were made in regions of interest in the liver, pancreas, and a reference marker with a known T1 value. Contrast index (CI, SItissue/SImarker) and contrast-to-noise ratio (CNR, [SItissue/SImarker]/SDbackground) were calculated, and percentage CI increase and CNR in the postcontrast images were used for the best sequence evaluation. Regarding CI, the TFE sequence with a TR/TE/flip angle of 15 msec/4.6 msec/20 degrees and inversion time of 300 msec had the largest pre- to postcontrast percentage increase. The FFE sequence with a TR/TE/flip angle of 140 msec/4.6 msec/90 degrees had the highest postcontrast CNR and is considered to be the optimal sequence for mangafodipir trisodium-enhanced MR imaging of the liver and pancreas.