MRI has for many years been the imaging modality of choice in human medicine for soft tissue, making it the gold standard for diagnosing pathology in orthopaedic and oncology studies. Hallmarq’s EQ2 system brings the same diagnostic capability to the equine clinical practice.

When tissue is placed in a strong magnetic field and a short pulse of radio waves is applied, a weak signal echoes back and is used to create an image

The tissue examined must be completely inside the magnet, limiting MRI to limbs (standing) and heads (in large, anesthesia only machines).

Because MRI transmits and receives radio signals, scanning must take place in a screened room MRI uses no ionising radiation and has no known hazardous biological effects

	What do MR images look like ?

The images appear as black-and-white slices through the tissue. The position of the slice is chosen by the scanner operator.

 

	Sequence types

The exact appearance of an MR image is determined by the timing of the various radiofrequency and magnetic field gradient pulses used to collect the data, collectively known as the imaging sequence. Different sequences generate images that show fat (eg in bone) and water (eg edema) at different brightnesses

A full range of sequences is available using the Hallmarq system, including T1 and T2 weighted gradient echo and fast spin echo images, and fat suppressed STIR images. All sequence types are available with motion detection and correction to assist scanning the higher joints.

T1 Weighted Sequence Optimised for visualisation of anatomical structures Typical Tissue Appearances Cartilage / Blood Vessels - Bright white Fat / Bone / Fibrous Tissues - Light Water / Synovial Fluids - Grey Tendon / Ligaments - Dark grey Cortical Bone - Black
	T2 weighted sequence Optimised for visualisation of inflammation in soft tissues Typical Tissue Appearances Cartilage / Synovial fluid - Bright Fat / Bone / Fibrous Tissues - Light Grey Ligaments - Grey Tendon - Dark grey Cortical bone - Dark
STIR sequence Optimised for visualisation of inflammation in bone Typical Tissue Appearances Synovial fluid / Water - Bright Fibrous Tissues - Light grey Fat - Dark grey Ligaments - Grey Tendon / Cortical bone –- Dark grey