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Perfusion Computed Tomography at Posttraumatic Cerebral Fat Embolism

Citation: Trofimov A, Kalentyev G, Yuryev M, Ruzavina A, Ksenofontova K, et al. (2017) Perfusion Computed Tomography at Posttraumatic Cerebral Fat Embolism. Open J Trauma 1(2): 029-031. Abstract The article reports a clinical case illustrating favorable outcome of nonsurgical treatment of a polytraumazed patient with occult severe cerebral fat embolism. The peculiar characteristics of the perfusion CT are demonstrated. Case Report


Introduction
Cerebral fat embolism (СFE) is one of the gravest complications in an acute posttraumatic period. According to data obtained by different authors its frequency in severe injuries varies from 0.5% to 30%. Its development is most often caused by fractures of the pelvis, long bones, by massive damage of subcutaneous fat [1].
Despite diverse suggested methods of treatment the mortality in case of the СFE development reaches nearly 70% [2].
In this connection, the possibility for the early FE diagnosing is of particular importance [1]. However, the role of radiological methods still remains to this day quite limited [3].
The use of magnetic resonance imaging (MRI) in patients with clinically diagnosed СFE has enabled to describe the socalled "starfi eld pattern", which is evident as multiple minor hyperintense foci of cortical-subcortical localization identifi ed in the diffusion-weighted image (DWI) mode [3].
The emergence of such a pattern was explained with the development of a cytotoxic edema in the area of the blood supply to the terminal branches of the cerebral arteries affected by fat emboli [4] (Figure 1).
The MRI semiotics was further exacted [5,6]. It was noted that at the subacute CFE stage on T2-weighted images some hyperintense foci may be identifi ed in the gray and white matter corresponding to vasogenic edema loci around an area of embolism [7].
However, in case of severe injuries patients oftentimes may not be subjected to MRI because of available metal implants and external apparatus for osteosynthesis (f.e., Ilizarov's apparatus) made of ferromagnetic materials [5].
But the use of the native computer tomography in case of CFE is limited because of its low diagnostic value [3].
On the another hand, the emergence and widespread routine-practice implementation of modern contrast methods for the cerebral microcirculation assessment, such as the perfusion computer tomography (PCT), may signifi cantly improve the CFE diagnosing and promptly start the expert care thereof [7].

Case Summary
A 36-years-old White male without past medical history was admitted with polytrauma after a road traffi c accident to To assess the cerebral microcirculation state, a perfusion brain CT was performed ( Figure 2).
The said cerebral perfusion changes were assessed by two independent radiologists as multiple foci of acute ischemic brain damage. The suggestion was made on the continuing CFE.
To make diagnosis, blood samples were drawn both from a vein and from a femoral artery. The fi ndings showed no fat globule in venous samples but large globules available in arterial blood (Figure 3).
Thus, there was identifi ed the acute hypoxic encephalopathy secondary to cerebral vessel fat embolism.
A specialized respiratory therapy was started (normobaric hyperoxia at the oxygen fl ow of 3.5 l/min under the cerebral oxymetry control). As recommended the hypolipidemic therapy with atorvastatin was assigned as well as anticoagulant and disaggregant therapy [1].
During the next few days the patient's condition signifi cantly improved as follows: focal symptoms regressed, psychotic phenomena stopped, the consciousness recovered to its normal state.
The patient was discharged in a satisfactory condition upon the expiry of 50 days after the injury for the follow-up stepwise care with using an Ilizarov' s apparatus for osteosynthesis with the satisfactory comparison of bone fragments.

Discussion
Cerebral fat embolism is a dangerous life-threatening complication of an acute period in fractures of long bones and pelvis. It most often causes the simultaneous brain damage and pulmonary injury [9,10].
However, the aspects of using neuroimaging for CFE diagnosis still remain poorly studied [11]. From the practical point of view the use of the PCT method for diagnosing CFE is affordable for performance at any trauma center and may considerably improve its timely diagnosis and the start of appropriate treatment.

Figure 2:
When studying the perfusion scans the attention is drawn to multiple foci with typical reduced values of blood fl ow and regional volume of blood supply and higher values of mean transit time and time of reaching the peak concentration of contrast agent (marked green in the Westermarkmask mode). These foci affect cortical-subcortical areas of almost all lobes in the both hemispheres and are not identifi ed by the native brain CT scan.