Neuroradiology 0028-3940

Capelastegui, Ana

doi: 10.1007/s00234-006-1462-4pmid: N/A

Essig, Marco

doi: 10.1007/s00234-006-1463-3pmid: 16699847

The challanging and multiple goals and requirements of CNS tumor imaging require optimization of the CNS imaging protocols, including selection of the optimal contrast medium. There are several gadolinium compounds available for imaging the CNS, and all of these except the compound Gd-BOPTA have nearly identical profiles. The unique protein interaction of Gd-BOPTA results in double T1 and T2 relaxivity. This article summarizes the advantages of Gd-BOPTA over conventional gadolinium compounds in both conventional and functional MR imaging. The results of recent studies in adults and pediatric patients are presented and discussed. The principal conclusion of this article is that not all contrast agents approved for MR imaging of the CNS behave in the same way. The use of the high-relaxivity agent Gd-BOPTA for morphological and functional MR imaging allows improved detection and delineation of CNS lesions compared to conventional gadolinium agents. This not only permits more confident diagnoses, but also results in a substantially improved differential diagnostic process. The higher relaxivity of Gd-BOPTA helps to optimize functional MR imaging studies e.g. perfusion MR imaging and other dynamic MR imaging protocols.

Anzalone, Nicoletta; Scotti, Roberta; Iadanza, Antonella

doi: 10.1007/s00234-006-1464-2pmid: 16699848

Several studies have shown the usefulness of contrast-enhanced MR angiography (CE-MRA) for imaging the supraortic vessels, and, as a consequence, it has rapidly become a routine imaging modality. The main advantage over unenhanced techniques is the possibility to acquire larger volumes, allowing demonstration of the carotid artery from its origin to the intracranial portion. Most published studies on CE-MRA of the carotid arteries have been performed with standard Gd-based chelates whose T1 relaxivity values are similar. Recently new gadolinium chelates such as gadobenate dimeglumine (Gd-BOP-TA, MultiHance; Bracco Imaging, Milan, Italy) have been developed which have markedly higher intravascular T1 relaxivity values. When administered at an equivalent dose to that of a standard agent, these newer contrast agents produce significantly greater intravascular signal enhancement. The availability of an appropriate high-relaxivity contrast agent might also help to overcome some of the intrinsic technical problems (e. g. those related to flow) that affect time-of-flight (TOF) and phase contrast (PC) MR angiography of the intracranial vasculature. To avoid the problem of superimposition of veins, ultrafast gradient echo MRA techniques with very short TR and TE have been developed. Although the precise sequence parameters vary between manufacturers, they are basically similar. The choice between performing a time-resolved or high spatial resolution CE-MRA examination depends upon the precise clinical application. The most common applications include the study of cerebral aneurysms, arteriovenous malformations, dural arteriovenous fistulas and dural venous diseases.

Colosimo, Cesare; Cianfoni, Alessandro; Lella, Giuseppe; Gaudino, Simona

doi: 10.1007/s00234-006-1465-1pmid: 16699849

The optimal protocols and the role of contrast agents in spinal MR imaging are controversial. Although the diagnosis of many common spinal diseases can be reliably achieved by means of unenhanced images, contrast use is often necessary to improve lesion detection and differential diagnosis. The heterogeneity of the different spinal compartments and the wide variety of spinal pathology require tailored imaging strategies. Thus, the rules to achieve optimization of contrast protocols for MR imaging of the spine are frequently very different to those for brain imaging, and depend on the location and site of origin of the lesions in a specific spinal compartment, on the findings of unenhanced imaging, and on the concomitant use of fat-suppression techniques. Furthermore, in most cases, the small size of the examined structures requires a meticulous technique, and the administration of a contrast agent with high relaxivity, such as MultiHance, is advisable to enable the detection of tiny areas of contrast enhancement. The applications and clinical utility of post-contrast MR imaging are discussed with regard to different spinal diseases.

Cotton, François

doi: 10.1007/s00234-006-1466-0pmid: 16699850

A high relaxivity contrast agent is indicated for use in MRI of the central nervous system to visualize lesions with an abnormal blood–brain barrier (BBB) or abnormal vascularity of the brain. We evaluated MultiHance (gadobenate dimeglumine, Gd-BOPTA) on T2*-weighted perfusion imaging in 33 histologically proven intra-axial brain tumors. The higher T1 relaxivity, and therefore better contrast-enhanced T1 imaging led to significantly better tumor delineation. The higher T2 relaxivity allowed high quality T2* perfusion MRI and post processed rCBV maps, with a dose of 0.1 mmol/kg MultiHance.