recent trend is to combine these modalities in order to enhance the precision of outlining the margins of the lesion. Three-dimensional information is essential for precise delineation of the contours. Unfortunately, MR images, when used alone, contain potential spatial inaccuracies. These arise from non-linearities inherent in MR physics. Some can be improved by careful quality control and choice of sequences. Certain factors, for example metallic foreign bodies, in the patient, which will distort the local magnetic field and create image artifacts, cannot be overcome. In contrast, the physics of CT is linear and allows greater spatial accuracy. Therefore, in the case of smaller targets, a combination (fusion) of MRI scan and CT scan is used. Such image fusion combines the advantages of the superior soft-tissue definition of MRI scanning and the precision of CT scanning. Co-registration of MRI and angiography helps in determining the three-dimensional distribution of an AVM nidus. The added combination of functional imaging with functional MRI (fMRI) and positron emission tomography (PET), etc., is being explored on an experimental basis. Having defined the coordinate system and, within this, the contours of the target, the treatment can be planned.
Was this article helpful?
The term vaginitis is one that is applied to any inflammation or infection of the vagina, and there are many different conditions that are categorized together under this ‘broad’ heading, including bacterial vaginosis, trichomoniasis and non-infectious vaginitis.