Congress:
EuroSafe Imaging 2019
Keywords:
Action 4 - Dose management systems, Neuroradiology brain, Emergency, CT, CT-Angiography, Radiation safety, Safety, Cardiac Assist Devices, Acute
Authors:
G. Coban, K. K. Oguz, K. Aytemir, E. B. Kaya, U. Canpolat, C. Eraslan, B. E. Çifçi, M. R. Onur, �. Parlak
DOI:
10.26044/esi2019/ESI-0073
Conclusion and recommendations
The diagnostic accuracy and reliability of an imaging technique is important for the diagnosis of a pathologic condition such as bleeding,
ischemia in a patient admitted to emergency department (ED) with acute neurological events.
Cranial CT is the most frequently preferred imaging modality in EDs and the utilization of cranial CT in the neurology and EDs has rapidly increased in the last decades (3,
11-12). In our study,
all the patients with ICD and LVAD who admitted to ED with neurological symptoms had one or more cranial CT scans as determined by study inclusion criteria.
Radiation dose reduction strategies are being more emphasized in recent years due to increased utility of CT with the advantages of high speed scanning and precious image quality.
Avoidance of unnecessary radiation dose in CT is crucial especially in children and women in childbearing age period.
However,
patients undergoing to repetitive CT scans regardless of age group may be counted in risk group in terms of ionizing radiation exposure due to cumulative dose burden.
In this group,
minimizing the number of CT scans should be the first strategy for reduction of dose burden.
If the number of repetitive CT scan can not be decreased adjustment and standardization of CT acquisition parameters under guidance of dose reduction techniques should be preferred. Our study was a multi-center based study and we had an opportunity to compare the CT acquisition parameters and dose products between different centers and CT vendors.
Applied CT acquisition parameters and resultant variable dose values of the three centers were more variable than expected which denotes the importance of standardization of cumulative dose producing repetitive CT examinations.
Also,
there was a significant difference in cumulative radiation exposure between LVAD and ICD group (p<0.001).
The reason for this difference may be attributed to the fact that patients with LVAD are more prone to hemorrhagic complications than ICD group.
Diagnosis of the parenchymal hematoma was significantly higher in patients with LVAD than the patients with ICD in our study.
However,
CT examinations performed due to suspicion of hemorrhagic complications do not require high kV tube potential and parenchymal hemorrhages can be detected with low kV values resulting in dose reduction.
Increasing the gantry rotation speed and the slice collimation (cSL) by changing detector configuration and preferring spiral scanning technique can decrease the radiation dose without lowering the CT image quality in terms of hemorrhage assessment.
Radiation exposure should always be managed in ALARA (As Low As Reasonably Achievable) principle.
We can manipulate the CT acquisition parameters,
in patients needed repetitive CT examinations,
by ongoing communication with the ED team and other physicians.
In patients with the suspicion of ischemia,
high tube voltage and low slice collimation may be important due to potential demand for high contrast resolution in order to visualize especially early ischemic regions.
However acute ischemic patients (n:13-7.7% of all patients) constituted low percentage of total patients in our study.
Also,
MR device compatibility could be questioned with more detail in patients with ICD,
and those patients’ neuro CT examinations could be replaced by a diffusion weighted MR imaging.
In our study,
we could not have a chance to questionaire the patients in detail for MRI compatibility.
Our study has several limitations,
first,
we were not able to find some of the CT acquisition parameters in the dose report of CT examinations,
that limited to evaluate the effects of each parameter on CT doses,.
Second limitation was the absence of knowledge about the neuroimaging history of these patients in centers other than those included in this study.
Third limitation was,
the absence of separate evaluation of the radiation dose burden parameters in cranial CT and head&neck CT angiography.
In conclusion,
neuro CT examinations are indispensable in neuroemergency settings.
In patients with cardiac device acute neurologic events may necessitate repetitive CT examinations which result in cumulative dose burden.
Applying radiation dose reduction techniques in this patient group can result in ‘damping’ effect in patient dose.