Imaging Pearls ❯ Vascular ❯ Hypotension
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- “In addition to being used to identify the underlying cause of the septic state, CT is required for the early recognition of shock-associated CT imaging signs, collectively referred to as CT hypoperfusion complex, which can improve patient prognosis and management. The CT hypoperfusion complex is frequently associated with hypotension, which can also present in many no sepsis related clinical conditions, such as trauma-induced hypotensive shock (e.g. severe head or spine injury), cardiac arrest, and diabetic ketoacidosis.”
Computed tomography imaging of septic shock. Beyond the cause: the “CT hypoperfusion complex”. A pictorial essay
Marco Di Serafino et al.
Insights Imaging (2021) 12:70 - “These signs include the decreased enhancement of the viscera, the increased mucosal enhancement and luminal dilation of the small bowel, the mural thickening and identification of fluid-filled loops in the small bowel, the halo sign and flattening of the inferior vena cava (IVC), reduced aortic diameter, peripancreatic oedema and other controversialparenchymal and visceral findings and ascites that can occur in varying combinations and are often and reversible during early stages. The presence of 2 or more vascular, visceral, or parenchymal signs is necessary to establish the presence of CT hypoperfusion complex.”
Computed tomography imaging of septic shock. Beyond the cause: the “CT hypoperfusion complex”. A pictorial essay
Marco Di Serafino et al.
Insights Imaging (2021) 12:70 - “The flattening of the IVC calibre has been defined as the identification of reduced anterior–posterior diameter (< 9 mm) in three consecutive segments, 20 mm above and below the renal veins, and at the level of the perihepatic portion. Flattening is the result of decreased circulating blood volume and indicates reduced venous return in patients with systemic hypotension, which may not be appreciable due to the massive infusion of liquids. In addition, variations in intra-abdominal pressure and the respiratory cycle can also affect the IVC diameter. IVC flattening has a specificity of 90% and a sensitivity of 84% for the identification of hypoperfusion shock due to sepsis in spontaneously breathing patients, whereas the sensitivity and specificity are both 90% in ventilated patients .”
Computed tomography imaging of septic shock. Beyond the cause: the “CT hypoperfusion complex”. A pictorial essay
Marco Di Serafino et al.
Insights Imaging (2021) 12:70 - “A small-calibre abdominal aorta is defined as a reduced anteroposterior diameter (< 13 mm) detected 20 mm above and below the renal arteries. Small-calibre aorta occurs in approximately 30% of patients with systemic hypotension and is not specific to hypoperfusive shock due to sepsis, as it may be observed in the normal population. This sign is associated with vasoconstriction induced by the adrenergic system to compensate for the shock condition.”
Computed tomography imaging of septic shock. Beyond the cause: the “CT hypoperfusion complex”. A pictorial essay
Marco Di Serafino et al.
Insights Imaging (2021) 12:70 - “The most frequent findings associated with shock bowel include fluid-filled, dilated loops with thickened walls (> 3 mm) due to oedema of the submucosa and increased mucosal enhancement relative to the psoas muscle . Changes to the small intestine are the most commonly observed characteristics among the CT signs indicative of shock. The small intestine is often diffusely involved in the occurrence of hypotensive shock, whereas the colon is rarely involved.”
Computed tomography imaging of septic shock. Beyond the cause: the “CT hypoperfusion complex”. A pictorial essay
Marco Di Serafino et al.
Insights Imaging (2021) 12:70 - “Abnormal renal perfusion typically manifests as an increased and prolonged parenchymal enhancement; however, focal and heterogeneous enhancement can also be observed. A fall in systolic pressure causes intense efferent glomerular arteriolar vasoconstriction, which drives glomerular filtration, leading to tubular stasis and the increased resorption of salt and water. Renal parenchymal enhancement is dependent on several factors, including cardiac output and scans timing relative to the injection of contrast agent and, thus, is a non-specific sign. However, kidney enhancement can vary depending on the severity of systemic hypotension. In some cases, unlike hyperenhancement, the decreased enhancement of the renal medulla can be observed in the venous phase, likely due to the impairment of contrast medium outflow from the renal cortex to the medulla, induced by acute renal tubular dysfunction and associated with poor prognosis.”
Computed tomography imaging of septic shock. Beyond the cause: the “CT hypoperfusion complex”. A pictorial essay
Marco Di Serafino et al.
Insights Imaging (2021) 12:70 - “The bilateral hyperenhancement of the adrenal gland is more common in paediatric cases than in adults and can also present in combination with acute adrenal haemorrhage, which most commonly affects the right side unilaterally, with a homogeneous increase in the size of the gland and the associated suffusion of fat around the adrenal gland. Bilateral adrenal hyperenhancement is the manifestation of adrenergic mechanisms that enhance the blood flow to the vital organs. In the arterial phase, the central zone of the adrenal gland shows less intense enhancement than the peripheral zone or presents a mosaic appearance due to the heterogeneous enhancement of the central zone. In both cases, in the venous phase, the whole adrenal gland is homogenously enhanced . This sign highlights the central role played by the adrenal glands in mediating the sympathetic response to hypotensive shock and is associated with poor prognosis.”
Computed tomography imaging of septic shock. Beyond the cause: the “CT hypoperfusion complex”. A pictorial essay
Marco Di Serafino et al.
Insights Imaging (2021) 12:70