Cortical rim sign (kidneys)
Updates to Article Attributes
The cortical rim sign is useful in distinguishing acute pyelonephritis from a segmental renal infarct and is seen on contrast enhanced CT or MRI.
The wedges of reduced enhancement seen in the setting of acute pyelonephritis represent oedema and ischaemia which involves the whole wedge of renal parenchyma, from medulla to the capsule. This sign, seen as a result of cortical necrosis, may also be seen in other conditions e.g. renal transplant rejection, intravascular haemolysis, shock, and as an obstetric complication 3.
In segmental infarcts, the blood supply to the outer aspect of the cortex is derived from perforating branches of the renal capsular artery which is an early branch of the renal artery. As such, when a branch of the renal artery is occluded (by thromboembolism, dissection etc) perfusion may be preserved to a thin rim (2-4 mm) of cortex which enhances normally.
Unfortunately the cortical rim sign is only seen in approximately half of renal infarcts.
See also
-<p>The <strong>cortical rim sign</strong> is useful in distinguishing <a href="/articles/acute-pyelonephritis-1">acute pyelonephritis</a> from a segmental <a href="/articles/renal-infarct">renal infarct</a> and is seen on contrast enhanced CT or MRI.</p><p>The wedges of reduced enhancement seen in the setting of <a href="/articles/acute-pyelonephritis-1">acute pyelonephritis</a> represent oedema and ischaemia which involves the whole wedge of renal parenchyma, from medulla to the capsule. This sign, seen as a result of <strong>cortical necrosis</strong>, may also be seen in other conditions e.g. renal transplant rejection, intravascular haemolysis, shock, and as an obstetric complication <sup>3</sup>.</p><p>In segmental infarcts, the blood supply to the outer aspect of the cortex is derived from perforating branches of the <a href="/articles/renal-capsular-artery">renal capsular artery</a> which is an early branch of the <a href="/articles/renal-artery">renal artery</a>. As such, when a branch of the renal artery is occluded (by thromboembolism, <a href="/articles/arterial-dissection">dissection</a> etc) perfusion may be preserved to a thin rim (2-4 mm) of cortex which enhances normally.</p><p>Unfortunately the cortical rim sign is only seen in approximately half of renal infarcts.</p><h4>See also</h4><ul><li><a href="/articles/rim-sign-in-renal-vascular-compromise">rim sign in renal vascular compromise</a></li></ul>- +<p>The <strong>cortical rim sign</strong> is useful in distinguishing <a href="/articles/acute-pyelonephritis-1">acute pyelonephritis</a> from a segmental <a href="/articles/renal-infarct">renal infarct</a> and is seen on contrast enhanced CT or MRI.</p><p>The wedges of reduced enhancement seen in the setting of <a href="/articles/acute-pyelonephritis-1">acute pyelonephritis</a> represent oedema and ischaemia which involves the whole wedge of renal parenchyma, from medulla to the capsule. This sign, seen as a result of cortical necrosis, may also be seen in other conditions e.g. renal transplant rejection, intravascular haemolysis, shock, and as an obstetric complication <sup>3</sup>.</p><p>In segmental infarcts, the blood supply to the outer aspect of the cortex is derived from perforating branches of the <a href="/articles/renal-capsular-artery">renal capsular artery</a> which is an early branch of the <a href="/articles/renal-artery">renal artery</a>. As such, when a branch of the renal artery is occluded (by thromboembolism, <a href="/articles/arterial-dissection">dissection</a> etc) perfusion may be preserved to a thin rim (2-4 mm) of cortex which enhances normally.</p><p>Unfortunately the cortical rim sign is only seen in approximately half of renal infarcts.</p><h4>See also</h4><ul><li><a href="/articles/rim-sign-in-renal-vascular-compromise">rim sign in renal vascular compromise</a></li></ul>
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