High intensity zone
Updates to Article Attributes
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was changed:
High intensity zone is defined as a bright white signal on T2W images in the posterior annulus of the disc and represents a fissure/tear in the posterior annulus.
Etiology
A high intensity zone (HIZ) generally occurs due to:
- post
traumatic-traumatic changes - instability of the spine and degenerative changes of the disc
Pathology
HIZs in the posterior annulus represent the in-growth of the vascularizedvascularised granulation tissue into the tears in the posterior part of the painful disc induced by inflammation. The posterior annular fibres are structurally weaker as compared to the anterior annular fibres thereby predisposing them to disruption 1.
Radiographic features
MRI
-
T2:high signal intensity
on sagittal T2W images notedin the posterior annulus on sagittal images - the HIZ
couldcan occur at the superior, middle or lower portions (most commonly) of the annulus -
generally involving thelumbar area at L4/5 and L5/S1 levels more commonly involved
See also
-<li>post traumatic changes </li>- +<li>post-traumatic changes </li>
-</ul><h4>Pathology</h4><p>HIZs in the posterior annulus represent the in-growth of the vascularized granulation tissue into the tears in the posterior part of the painful disc induced by inflammation. The posterior annular fibres are structurally weaker as compared to the anterior annular fibres thereby predisposing to disruption <sup>1</sup>. </p><h4>Radiographic features</h4><h6>MRI</h6><ul>-<li>high signal intensity on sagittal T2W images noted in the posterior annulus</li>-<li>the HIZ could occur at the superior, middle or lower portions (most commonly) of the annulus</li>-<li>generally involving the lumbar area at L4/5 and L5/S1 levels more commonly</li>- +</ul><h4>Pathology</h4><p>HIZs in the posterior annulus represent the in-growth of the vascularised granulation tissue into the tears in the posterior part of the painful disc induced by inflammation. The posterior annular fibres are structurally weaker as compared to the anterior annular fibres thereby predisposing them to disruption <sup>1</sup>. </p><h4>Radiographic features</h4><h6>MRI</h6><ul>
- +<li>
- +<strong>T2:</strong> high signal intensity in the posterior annulus on sagittal images </li>
- +<li>the HIZ can occur at the superior, middle or lower portions (most commonly) of the annulus</li>
- +<li>lumbar area at L4/5 and L5/S1 levels more commonly involved</li>
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