Aortic transsection after blunt chest trauma.

We report a case of an 18-year-old female who developed an extensive hemothorax after blunt chest trauma. Transesophageal echocardiography (TEE) showed transsection of the aorta at the level of the isthmus and turbulent flows in several places around the aorta. We discuss the contribution of TEE for detecting traumatic injuries to the thoracic aorta.

Oral magnetic particles as a contrast agent for MR imaging of the abdomen. A phase III clinical trial.

Twenty patients were investigated with MR imaging of the abdomen before and after the administration of oral magnetic particles in the form of a per os solution for opacification of the gastrointestinal lumen. The parameters which were evaluated were a) distribution of the contrast medium in the gastrointestinal tract, b) delineation with the contrast medium of the region of interest c) image quality of general contract effect of the contrast medium d) diagnostic accuracy compared with CT and plain MRI of the same region. At a concentration of 0.5 mg/oral magnetic particles produced a constant negative signal from the gastro- intestinal tract in all spin echo sequences (T1 weighted, T2 weighted, proton density). Its diagnostic accuracy was similar to CT but better than plain MR examination of the same region in 70% of the cases. The diagnostic accuracy was inferior in the lower abdomen because of underdistension of the bowel. Perhaps the solution to the problem would be the combined per os and per rectum administration of the contrast medium.

A comparative study between Gd-DTPA and oral magnetic particles (OMP) as gastrointestinal (GI) contrast agents for MRI of the abdomen.

In the present study we compared two gastrointestinal contrast agents--Gd-DTPA, a positive signal, and oral magnetic particles (OMP), a negative signal contrast agent--in patients who were referred for MR imaging of the abdomen. Altogether 60 patients were examined with the former and 28 patients with the latter contrast before and after the administration of contrast media. Gd-DTPA was given either per os or per rectum. In comparing the results, it was shown that the diagnostic accuracy of postcontrast MRI in both groups was more or less similar to CT but much higher as compared with plain MRI. In the OMP series, first the contrast between the GI-filled lumen and the surrounding fat was much superior to that of the Gd-DTPA and, second, there was no evidence of any artifacts from bowel motion. However, the overall accuracy of the Gd-DTPA group was better compared with that of the OMP group. This was due to underfilling of the distal bowel because the OMP in those patients was administered only per os. Finally, Gd-DTPA had a more pleasant taste and fewer side effects. It is concluded that both contrast media are suitable for the upper abdomen because the results are comparable, whereas for the lower abdomen Gd-DTPA is superior because it can be used from both routes.

CT and MR of pineal region tumors.

Magnetic Resonance (MR) imaging features of pineal region tumors were analyzed in 14 oncologic cases. The tumors were classified as germ-cell tumors, glial tumors, pineal parenchymal tumors, meningiomas, and cysts. They demonstrated different MR signal characteristics on precontrast scans and nodular or ring type enhancement with occasional central lucencies, except for benign cysts, which have not shown enhancement. MR images were useful in defining the relationship of the tumor to the posterior third ventricle, sylvian aqueduct, vein of Galen, and tentorium. Although CT can demonstrate in more evident fashion displacement of the original pineal calcification as well as tumor calcifications, MR imaging demonstrates different signal characteristics in germinomas and pineoblastomas which can be a useful adjunct in the evaluation and differential diagnosis of these tumors.

Gd-DTPA as an intestinal contrast agent for MR imaging of the lower abdomen: phase III clinical trial.

Thirty-one patients were investigated with magnetic resonance (MR) imaging of the lower abdomen before and after the administration of gadopentetate dimeglumine (Gd-DTPA) solution per os or per rectum or from both routes for the opacification of the intestinal tract. The parameters evaluated were: (a) contrast medium distribution, (b) degree of filling of the bowel lumen, (c) contrast between the bowel lumen and the surrounding normal or pathological structures, and (d) whether the administration of the contrast agent improved the diagnostic ability of MR compared to computed tomography (CT) or plain MR of the same region. Gd-DTPA, at a concentration of 1 mmol/L, produced a positive signal irrespective of its dilution in the bowel and good contrast between the bowel lumen and the adjacent tissues or any possible pathological lesions. From the diagnostic point of view, after the administration of contrast medium, MR is comparable to CT and much superior to plain MR. It is concluded that opacification of the bowel with Gd-DTPA solution will improve the diagnostic yield of MR imaging of the lower abdomen.