VIENNA - Originally intended for imaging the liver, the contrast agent mangafodipir trisodium (Teslascan from Nycomed Amersham) does improve MR imaging of the pancreas, and may be particularly effective for the preoperative staging of pancreatic cancer.
In a series of presentations at the European Congress of Radiology conference on March 6, clinicians spoke favorably of mangafodipir-enhanced imaging.
"Today, the preferred method (of diagnosis) is still CT. Because surgery is the only curative treatment (for pancreatic carcinoma), the goal now is to improve diagnosis. There is a clinical need for earlier detection," said Dr. Bart Op de Beeck from the University of Belgium in Brussels. "Non-enhanced MR has shown poor initial results because there are a lot of artifacts. This problem is solved by this technique."
Op de Beeck, as well as researchers from Italy and Spain, tested mangafodipir-enhanced MR against contrast-enhanced CT. In this study, images of 140 patients who were suspected of having pancreatic lesions were evaluated. CT and MRI were performed on all patients, and blinded readings were done.
According to the results, contrast-enhanced MR was as good as CT. The first reader had the correct diagnosis in 65% of the cases with MRI and in 62% of the cases with CT. The second reader's results came in at 56% for MRI and 55% for CT; the third reader had the correct diagnosis in 43% of the patients who underwent MRI and 38% of those imaged with CT.
In a second presentation, Austrian clinicians found that mangafodipir-enhanced MR was able to catch one lesion that CT did not. The group from the University of Vienna did a prospective evaluation of 35 patients with suspected pancreatic masses. All patients underwent dual-phase, contrast-enhanced helical CT and MRI at 1.5 tesla. Sequences obtained were T2-weighted, TSE pre-contrast; pre and post-mangafodipir T1-weighted SE; and T1-weighted GRE with and without fat saturation. The presence of lesions, vascular invasion, lymph node or liver metastases was assessed.
The group was looking for correct staging information, the detection of small cancers, and the ability to differentiate between cancer and focal pancreatitis, explained Dr. Wolfgang Schima from the University of Vienna.
Thirty-two patients had masses in the pancreas, with 24 cases of cancer and seven cases of pancreatitis. Overall, MR had an accuracy rate of 92% while CT had an accuracy rate of 81%. CT missed one small lesion and yielded one false positive. For the detection of vascular invasion, MRI and CT had one false positive each. Liver metastases were missed by MRI in two patients and by CT in four.
Mangafodipir-enhanced MRI can improve detection of small cancers, while large tumors are better imaged with CT, Schima concluded.
Other issues addressed in the scientific session:
- German researchers from Friedrich Alexander University in Erlangen found that mangafodipir-enhanced MR offered better visualization and characterization of focal pancreatic disease.
- Patients reported some discomfort when the contrast agent was used, including extreme warmth, cold, pressure, and nocturia, according to a report from a multicenter, Phase III clinical trial of mangafodipir-enhanced imaging. Institutions involved were located in seven German cities, including Lubeck, Augsburg, Dresden, and Mannheim.
- Both CT and MRI should be used together for optimal pancreatic imaging, according to researchers from Ulleval University Hospital in Oslo, Norway. Mangafodipir-enhanced imaging could improve the staging, thus eliminating unnecessary surgical procedures.
- One stumbling block that any kind of pancreatic imaging modality must contend with is the inability to differentiate between cancer and pancreatitis, said Dr. Martin Dobritz from Freidrich University. Larger studies are needed to determine if mangafodipir-enhanced imaging can overcome this problem, he said.
By Shalmali Pal
AuntMinnie.com staff writer
March 7, 2000
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