Neurology

An assessment on the use of infra-scanner for the diagnosis of the brain hematoma in head trauma

a b s t r a c t

Purpose: Timely identification and treatment of intracranial hematomas in patients with brain injury is essential for successful treatment. This study evaluates Infra-scanner as a handy medical screening tool for diagnosing, on- site, cerebral hematomas in patients with head injury.

Materials and methods: Patients referred to the emergency department of university hospitals with mild to mod- erate brain trauma, up to 12 h from injury were included. NIR sensors of infra-scan device were placed on the right and left frontal, temporal, peritoneal and occipital parts of the head and light absorption was recorded. Pos- itive or negative cerebral hemorrhage cases were compared with contrast-enhanced CT scan results as the gold standard. Diagnostic parameters of the device and cases related to bleeding were analyzed and reported.

Results: A total of 300 patients were studied. Sensitivity of the infrasound scanner in the Iranian study population was 94.8 (95% CI: 88% -100) and its specificity was 86.9 (95% CI: 79% -99% 99). Negative predictive value (NPV) was 90.3% and positive predictive value (PPV) was 92.9%. Sensitivity in men (95.7%) (95%CI, 90% -1) was more than women (95% CI, 81% -99%)90%. At the ages of less than 36 years, sensitivity (95.3%) and specificity (87.1%) were more than sensitivity (94.4%) and specificity (86.5%) over 36 years old. If the test had been per- formed in less than / equal to two hours from trauma, the sensitivity (94.9%) and the specificity (92%) were greater than the sensitivity (94.6%) and the specificity (75%) during when the scan had been performed in more than two hours from trauma. In general, in extra-axial bleeding including EDH, SAH, SDH, the sensitivity was 95.1% and the specificity was 84.5%, while in intra-axial bleeding, including ICH and IVH, the sensitivity was lower (93.9%) and the specificity was 91.7. The sensitivity of the device in detecting bleeding in the occipital lobe (95.8%) was higher than other brain lobes.

* Corresponding author at: Iran University of Medical Sciences, Shahid Hemmat Highway, Tehran 1449614535, Iran.

?? Corresponding author.

E-mail addresses: [email protected] (M.T. Joghataei), [email protected] (M.R. Motamed).

+ These authors have equal contribution to this manuscript.

https://doi.org/10.1016/j.ajem.2021.09.074 0735-6757/(C) 2021 Published by Elsevier Inc.

Conclusion: This study shows that Infra-scanner is useful in initial examination and screening of patients with head injury and can be used as an adjunct to a CT scan or when not available and may allow earlier treatment which reduce the Secondary damage to the hematoma.

(C) 2021 Published by Elsevier Inc.

  1. Introduction

Time of diagnosis and management of intracranial hematoma is cru- cial for successful treatment, especially since the spread of bleeding can lead to disability and sometimes death [1]. About 1.4 million people suf- fer from Traumatic brain injury each year, resulting in 1.1 million Hospital visits, 235,000 hospitalizations, and 50,000 deaths [2]. Studies have referred TBI as “silent epidemic, since it a serious Public health concern and adds significantly to morbidities, disabilities and mortality, worldwide [3]. Brain trauma is a serious health problem among people aged 15 to 24, which accounts for about 2.3 cases of trauma to the head of children and adults. Similarly, TBI also can cause serious outcomes in elderly patients, aged >75 years [2].

Focal causes of brain damage include inflammation of the brain tis- sue (contusion) and rupture of the internal arteries of the skull that causes Intracranial Hemorrhage or hematoma [4]. Bleeding can be inside the skull but outside the brain (extra-axial) or inside the brain tissue (intra-axial). Extra-axial bleeding includes epidural, sub- dural and subarachnoid hematoma. Intra-axial bleeding is called hema- toma. Mortality after closed brain injury with focal lesion is 39%, compared with extensive brain injury which is 24% [5].

To date, the Computerized Axial Tomography (CT) is the gold standard of detecting hematomas due to TBI. Nevertheless, CT scans are not always available at the time of a trauma or a vascular event. Furthermore, it is difficult to identify high-risk patients who would require CT scan promptly [6]. Primarily, Neurological examination is performed based on clinical sign and symptoms. However, intracra- nial hematoma may not always be presented with immediate signs and symptoms [7,8].

Infra scanner uses Near-infrared spectroscopy (NIRS) and can be used for identification of intracranial hematomas prior to CT scan. Infra scanner detects hematomas that are at least 3.5 ml in size and up to 2.5 cm deep from the surface of the cortex [9,10]. The Infra scanner offers information that could be beneficial in initial assessments of pa- tients with possible brain injury (i.e., at the site of the accident or in emergency rooms where CT scans are not immediately available or pa- tient is required to be sedated) [11]. The relatively high sensitivity of the device can introduce it as a reliable screening device that acts as a pa- tient risk determinant before CT scan, or even in cases of high-risk acci- dents, it can indicate the requirement immediate CT scan [6].

The purpose of this study is to evaluate the Infra scanner as a hand- held medical screening tool for the in-situ detection of brain hemato- mas in patients with head injury. To our knowledge this is the first study conducted in (XXX). The validity of the test was evaluated com- paring to Brain CT scan. This study was also designed to evaluate the Infra scanner classification accuracy in detecting different kinds of hematomas.

  1. Materials and methods
    1. Patients

This multicentric study was performed on patients admitted to the Emergency Room Observation Unit at three central hospitals affiliated to (XXX) which are considered as Level 1 trauma centers from January 2019 – December 2019. Written consent was obtained from all the pa- tients prior to the inclusion in the study. Inclusion criteria were age >= 18-year-old, history of Minor or Moderate Head trauma during past

12 h. Exclusion criteria was age < 18 years old and major head trauma requiring prompt surgical management. Briefly, after admitting a TBI patient, Emergency doctors requested a CT scan and an Infra-scanner exam. In some cases, the Infra-scanner exam was performed before the CT scan, based on the patients’ medical conditions. All the patients were managed according to Brain Trauma Foundation guidelines and local protocols. Technicians in both the cases were blinded and were un- aware of the results of prior imaging modality.

Brain CT scans were reported by an experienced neuroradiologist, blind to the study goals and NIRS data. A CT scan with hyperdense im- ages was considered pathological. Hematoma characteristics, including type, and volume (gauged in mL) were noted. Extra-axial bleeding in- cluded EDH (extradural hemorrhage), SAH (subarachnoid hemor- rhage), and SDH (subdural hemorrhage), while intra -axial bleeding included ICH (intracranial hemorrhage) and IVH (intraventricular hemorrhage).

    1. Procedure

The Infra-scanner NIRS device (InfraScan, Inc., Philadelphia, PA) (Fig. 1) was used in this study. The length of exam is usually 3 min. The device utilizes some light sensors to receive information from the scalp surface and compute optical density in different regions of brain. Based on standard data acquisition protocol the Infra-scanner performs symmetrical readings in the four main brain lobes: frontal, temporal, parietal and occipital. Hematoma detection derives from the difference in optical density between left and right readings for each brain lobe. Extravascular blood absorbs more NIRS light compared to intravascular blood because of the greater concentration of hemoglobin in the acute hematoma than in the brain tissue, where blood is inside the vessels. Therefore, the absorbance of NIRS light is greater. This means that the reflected light absorbance is lesser on the side of the brain with hemor- rhage. This system includes two main components: a NIRS-based sensor and a wireless personal digital assistant (PDA). The NIRS Sensor has two components: a safe Class-I 808 nm wavelength diode laser and a silicon detector. The NIRS light source emits a light through disposable light guides in a ‘hairbrush’ like configuration that allows the sensor to con- tact the skin of the scalp. The light penetrates the brain and is registered by the NIRS detector connected to the scalp through two optic fibers. There is a 4.0 cm distance between light source and detector, which lets NIRS absorbance measurement in tissue volume with 2 cm of

Image of Fig. 1

Fig. 1. The infra-scanner device.

width and 2-3 cm of depth. The detector is shielded by a band pass filter to minimize interfering with the background light. Electric circuitry is also involved to control laser power and detector signal amplifier gain. The detected signal is digitized and transmitted to a Bluetooth wireless personal digital assistant (PDA) that displays the results on the screen.

Table 2

Sub analysis of Infrascanner characteristics for diagnosing brain hematoma.

Sensitivity % Specificity %

Gender

The PDA automatically adjusts its settings to ensure good Data quality. The data is further processed, and the results are shown on the PDA screen.

The difference in optical density (DOD) in the different areas is com- puted using the following formula:

?OD 1/4 log 10INIH

Female 90%

(n = 30)

Male 95.7%

(n = 163)

Age

age < 36 95.3%

(n = 85)

age > 36 94.4%

(n = 108)

100%

(n = 15)

84.8%

(n = 92)

87.1%

(n = 70)

86.5%

(n = 37)

where IN is the intensity of reflected light on the normal side and IH is the intensity of reflected light on the hematoma side. Intracranial hema- toma detection was established when DOD > 0.2 units occurred in a particular pair of bilateral measurements. When a measurement shows a difference of 0.2 OD or greater, the measurement pair was repeated twice to confirm the presence of a hematoma. A DOD_0.2 units was con-

Injury- screen time

Time <= 2 h 94.9%

(n = 137)

Time > 2 h 94.6%

(n = 56)

Bleeding type

92%

(n = 75)

75%

(n = 32)

sidered a negative exam. The 0.2 cut-off for the Infrascanner was set fol-

lowing a previous study on hematoma detection using NIRS [23]. Based on previous studies [11], >85% of intracranial hematomas can be de-

Extra-axial 95.1% (n = 144) 84.5 (n = 71)

Intra-axial 93.9 (n = 49) 91.7% (n = 36)

Brain lobes

tected using a 0.2 cut-off. NIRS exams were performed by two trained medical technicians, who were also blinded to CT scan results.

    1. Statistical analysis

NIRS accuracy indexes in hematoma detection were first calculated using CT scan results as the comparative gold standard. Statistical anal- yses were performed using SPSS v 22. Overall sensitivity and specificity

Frontal 90.9%

(n = 33)

Temporal 85.7%

(n = 21)

Parietal 68.8%

(n = 16)

Occipital 91.9%

(n = 37)

95.6%

(n = 68)

93.5%

(n = 46)

94.5%

(n = 55)

95.8%

(n = 24)

analyses were performed, using comparisons between NIRS and CT scan results. True positives, false positives, true negatives and false negatives were counted and used.

to estimate both sensitivity (true positives/true positivesfalse nega- tives) and specificity (true negative/ false positivetrue negative). Posi- tive predictive values (true positive/ false positive), negative predictive values (true negative/ false negatives) and their respective 95% confidence intervals (CI) were also calculated. Subsequent analysis included estimating NIRS classification accuracy indexes for intra-axial/ extra-axial hematomas, injury-screen time, gender, age, brain lobes were conducted.

    1. Ethics

The Hospital Institutional Review Board approved this study, and all procedures were in accordance with the Declaration of Helsinki guide- lines.

  1. Results

This study included 300 TBI patients, including 255 (85%) males and 45 (15%) females, age ranging from 11 to 89 years (39.4 +- 18.6). All tests were performed <=12 h from the injury and the mean time between NIRS exam and head trauma was 2.7 +- 2.6 h. Mean bleeding volume was 10.1 +- 6.3 ml. There were 66 EDH (22%), 99 cases of SDH (33%),

62 cases of ICH (20.7%), and 50 cases of SAH (16.7%), and 23 cases of

IVH (7.7%).

Overall diagnostic indexes obtained from the TBI patient group showed that the Infrascanner sensitivity was 94.8% (95%CI, 88%-100) and specificity was 86.9% (95%CI,79%-99%) with the accuracy of 92%. Additionally, PPV and NPV were 92.9% and 90.3% respectively (Table 1). Sensitivity in men 95.7% (95% CI: 90% -1%) was higher than women 90% (95% CI: 81% -99%) but specificity in women was 100% and in men

was 84.8% (95% CI, 74% -96). The diagnostic data for men and women are summarized in Table 2.

The results also showed that at the age of less than 36 years, sensitiv- ity (95.3%) and specificity (87.1%) was higher than sensitivity (94.4%) and specificity (86.5%) in patients aged more than 36 years (Table 2).

The results of the study showed that if the test is performed with an infrascanner device in less than/equal to two hours with trauma, the sensitivity (94.9%) and specificity (92%) are higher than the sensitivity (94.6%) and specificity (75%) when the scan time was more than two hours (Table 2).

In the case of various types of cerebral hemorrhage following con- cussion, in general extra-axial hemorrhages including EDH, SAH, SDH had a sensitivity of 95.1% and specificity of 84.5%, while in intra-axial hemorrhages including ICH and IVH, less sensitivity (93.9%) and less specificity (91.7%) (Table 2).

The sensitivity of the device to bleeding in each brain lobe is summa- rized in Table 3. The sensitivity of the device in detecting bleeding in the

Table 3

Sensitivity of infra-scanner device in diagnosing cerebral hemorrhage by cerebral lips.

Brain lobe Sensitivity Specificity

Table 1

Infrascanner characteristics for diagnosing brain hematoma.

Index Percentage

Sensitivity 94.8%(n = 193)

Specificity 86.9% (n = 107)

PPV 92.9%(n = 197)

NPV 90.3%(n = 103)

Frontal 95.6%

(n = 68)

Temporal 93.5%

(n = 46)

Parietal 94.5%

(n = 55)

Occipital 95.8%

(n = 24)

90.9%

(n = 33)

85.7%

(n = 21)

68.8%

(n = 16)

91.9%

(n = 37)

Image of Fig. 2

Fig. 2. An example of the infra-scanner data acquisition.

occipital lobe (95.8%) was higher than other brain lobes, followed by the frontal lobe (95.6%) and the peritoneal lobe (94.5%) and less than the temporal lobe (93.5%). The specificity of the device in detecting occipital lobe bleeding (91.9%) was from other brain lobes and the lowest feature was related to peritoneal lobe (68.8%) (Figs. 2,3).

  1. Discussion

Infra-scanning device was performed on 300 patients with mild and moderate trauma in the Iranian population (according to the anatomy of the head), which is a good number for analysis and decision making and is more than similar cases in other articles. Inclusion criteria were mild or moderate trauma and trauma below 12 h, which according to previous studies is the most optimal way to detect bleeding by the de- vice. Intracranial pressure is considered as a mainstay for the manage- ment of TBI and studies have suggested that NRIS is effective tool for detecting changes in intracranial pressure [12]. NIRS can be used to evaluate acute intracranial hematoma in out-hospital settings where, locating of brain lesion is important to determine TBI resuscitation tech- niques, in addition to direct transport of patients to neurological units. It can also be used for initial screening in the centers where availability of

CT scan is demanding. However, it cannot be used as a replacement of CT scan [13].

The most important results of this study are that the hand-held in- frared infra scanner in the Iranian population has a sensitivity of 94.8%, a specificity of 86.9% and accuracy of 92% in the diagnosis of inter- nal and extra-axial traumatic hematomas in the Iranian population. It should be noted that the false negatives of the device are very low (5.2%), which still shows the value of the device as an initial screening device for patients with hematoma. False positives of the device (13.1%) are acceptable and more than false negatives, which can be seen in the case of efficient Screening tests.

In studies by Robertson, Zager [14] and Leon-Carrion, Dominguez- Roldan [11] sensitivity was 89.5 and 88%, respectively whereas the specificity in those studies was 90.7% and 81.2%. Another study of 85 patients in China showed NIR sensitivity is 95.2% and specificity is 92.5% in the diagnosis of intracranial hematomas larger than 3.5 ml in volume; The distance from the surface of the brain was less than

2.5 Xu, Tao [15]. In other studies, sensitivity of infra scanner in adults is reported to be 92.5% and in children is 93% whereas, specificity in adults 82.9% and in children 82.5% for the diagnosis of intracranial hematomas [9].

Image of Fig. 3

Fig. 3. Samples of pathological CT scans and Infrascanner detections. Images on the left show CT scan results. Images on the right show corresponding hematoma detection by the Infrascanner exam.

The results of our study show that in men the sensitivity is 95.7% which is higher than women (90%) while the specificity in women is 100% and in men is 84.8%. These differences have not been studied sep- arately in other studies. However, only 15% of our study population were female, making the two populations (men and women) statisti- cally incomparable. Another finding of this study is that at the age of less than 36 years, sensitivity is 95.3% and specificity is 87.1% which is higher than sensitivity 94.4% and specificity 86.5% above 36 years, al- though this difference is not significant and the device appears to be us- able at any age, but this may mean that the device is more valuable for diagnosing bleeding at younger ages (less than 36 years). These differ- ences have not been studied separately in other studies. The difference in these findings could be due to sage-related calcifications in the brain parenchyma and blood vessel wall, which reduces infrared passage, leading to the reduction in the diagnostic power of the device [16,17]. Furthermore, the device has high sensitivity and specificity to scalp lesions that can give false positive results for cerebral hematoma [18].

Because the function of the device depends on the characteristics of acute bleeding and chronic subcutaneous hematoma, dural hematoma cannot be reliably detected with this method. Probably because the products of hemoglobin breakdown in chronic hematoma do not have the same light absorption properties [11]. The results of our study also showed that in extra-axial hemorrhages including EDH SAH, SDH sensi- tivity (95.1%) and specificity (84.5%) is higher than intra-axial hemor- rhages including ICH and IVH with sensitivity (93.9%) and specificity

(91.7%). It is also shown that the infra-scanner device has a higher sen- sitivity and specificity in extra-axial bleeding than intra-axial bleeding, which is because the bleeding is more superficial and closer to the sur- face (location of the device) [11]. For traumatic brain injury in which the majority of hematomas are SDH and extra-axial (EDH) [15] sensitivity is appropriate. A systemic review and meta-analysis concluded that cross- study sensitivity of the device for the diagnosis of intracranial hema- toma is 78% and sensitivity is 90% [19].

The sensitivity of the device in the study population for the diagnosis of bleeding in the occipital lobe was highest (95.8%) than other brain lobes and least was seen in the temporal lobe 93%. These parameters have not been studied in other studies. Infra Scanner is an efficient screen- ing solution for head trauma patients in pre-hospital settings where timely triage is crucial. The clinical usefulness of this technology for iden- tifying hematomas will depend on the type of brain disorder being stud- ied. Because the infra-scan device is relatively inexpensive and due to the dimensions of the device, its portability, ease of use and also its availability compared to CT Scan can be used in all first aid centers and ambulances and seems to be the choice Suitable for initial screening of brain trauma patients, especially in Low- and middle-income countries [20].

In our study, bleeding time of 1-12 h is only included. Bleeding more than 12 h is not evaluated for the efficacy of the device. It is recom- mended that diagnostic indicators of infra-scanner in the diagnosis of cerebral hemorrhage in patients with acute neurological symptoms (SAMA code) should be referred to the hospital emergency department.

Our study is limited to small sample size and provides data regarding 12 h of trauma only. Furthermore, our population is not gender-wise homogenous and data regarding the depth of lesion cannot be pre- sented with infrascanner. Our study does not provide data regarding long-term follow up of these patients and the volume calculated by NIRS and CT. We also do not provide data regarding vitals of the patients and the decision of infrascanner against the indications by vitals was also not evaluated. Second infrascanner results can improve the speci- ficity of the device. We recommend future researches on less severely injured patients and their referral to level 1 trauma center based on the findings to improve patient triage and speed up the transfer of the patients.

  1. Conclusion

This study showed that infrascanner, as an easy-to-use portable de- vice, is a useful primary screening tool for brain trauma patients in the Iranian population to diagnose traumatic brain hematomas. The device can allow paramedics, emergency department physicians and hospital staff to make better decisions about triage and earlier treatment and re- duce secondary brain damage from acute and delayed injury. NPV and specificity of infrascanner in overall study population was not excellent, indicating that the device might be suitable for certain subgroups such as age above 36 years and the type of hematoma.

Ethics

The Hospital Institutional Review Board approved this study, and all procedures were in accordance with the Declaration of Helsinki guide- lines.

Ethics approval and consent to participate

This study is approved by Ethics Committee of Vice Chancellor for Research & Technology of the Iran University of Medical Sciences (IUMS). All patients and Control subjects signed the informed consent. This study was performed in accordance with the ethical standards of the Declaration of Helsinki (2013) and its subsequent amendments.

Consent for publication

Informed consent were obtained from all patients whom clinical data were reported in this article to participate in the study and assess- ments.

Availability of data and materials

The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.

Funding

This study did not receive any specific grant from any companies, funding agencies in the public, commercial, or not-for-profit sectors.

Contributors’ statement page

Dr. Sara Esmaeili and Dr. Mohammad Taghi Joghataei and Dr. Mohammad Reza Motamed.: conceptualized and designed the study, drafted the initial manuscript, and reviewed and revised the manuscript.

Dr. Mohammad Mojtahed and Dr. Zahra Mirzaasgari and Dr. Seyedeh Niloufar Rafiee Alavi and Dr. Meysam Abolmaali and Dr. Gholamreza Masoumi and Dr. Samira Chaibakhsh and Dr. Mahya Naderkhani: Designed the data collection instruments,

collected data, carried out the initial analyses, and reviewed and re- vised the manuscript.

Dr. Ali Famouri and Dr. Sepideh Allahdadian and Dr. Saeid Gholami gharab and Dr. Amir Nejati and Dr. Aram Zabeti and Dr. Peyman Shirani: Coordinated and supervised data collection, and critically reviewed the manuscript for important intellectual content.

Declaration of Competing Interest

Authors have no competing interests to declare.

Acknowledgments

This study was supported by the Iran University of Medical Sciences (research grant No. 99-1-20-17447)). We would like to thank our col- leagues for their valuable comments that greatly improved this manu- script.We would like to thank Maryam Daneshgar for her valubale support.

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