The partial volume effect is the loss of contrast between two adjacent tissues in an image caused by insufficient resolution so that more than one tissue type occupies the same voxel (or pixel). That may induce a partial volume artifact, dependent on the size of the image voxel. If fat and water spins occupy the same voxel, their signals interfere destructively. A small amount of water signal may be eliminated by a larger lipid signal from the same voxel, resulting in a voxel that appears to contain only lipid. The partial volume effect is minimal with thin slice thickness and sufficiently high resolution, so that fat and water or other different structures are unlikely to occupy the same voxel.

Take thinner slices, and higher resolution (smaller voxel), but remain this may result in poorer signal to noise ratio in the image.

Quick Overview

The Partial Volume Artifact is caused by imaging voxel containing two different tissues and therefore possessing a signal average of both tissues.

Take thinner slices (smaller voxel), but this may result in poorer signal to noise ratio in the image.

See Partial Volume Effect.

(MR mammography) Magnetic resonance imaging of the breast is particularly useful in evaluation of newly diagnosed breast cancer, in women whose breast tissue is mammographically very dense and for screening in women with a high lifetime risk of breast cancer because of their family history or genetic disposition.
Breast MRI can be performed on all standard whole body magnets at a field strength of 0.5 T - 1.5 Tesla. Powerful gradient strengths over 15 mT/m will help to improve the balance between spatial resolution, scanning speed, and volume coverage. The use of a dedicated bilateral breast coil is obligatory.
Malignant lesions release angiogenic factors that increase local vessel density and vessel permeability. Breast cancer is detectable due to the strong enhancement in dynamic breast imaging that peaks early (about 1-2 min.) after contrast medium injection. If breast cancer is suspected, a breast biopsy may be necessary to secure the diagnosis.

See also Magnetic Resonance Imaging MRI, Biopsy and MR Guided Interventions.

Requirements in breast MRI procedures:
For Ultrasound Imaging (USI) see Breast Ultrasound at Medical-Ultrasound-Imaging.com.

See also the related poll result: 'MRI will have replaced 50% of x-ray exams by'

(THK) The thickness of an imaging slice. As the slice profile may not be sharp edged, a criterion such as the distance between the points at half the sensitivity of the maximum (FWHM) or the equivalent rectangular width (the width of a rectangular slice profile with the same maximum height and same area) is used to determine thickness.

For the image quality its important to choose the best fitting slice thickness for an examination. When a small item is entirely contained within the slice thickness with other tissue of differing signal intensity then the resulting signal displayed on the image is a combination of these two intensities. If the slice is the same thickness or thinner than the small structure, only that structures signal intensity is displayed on the image. This partial volume averaging effect explains the vanishing of fine details by choosing slices too large for the scanned object.

See also Partial Volume Artifact.