Emerg Radiol (2016) 23:9–16 DOI 10.1007/s10140-015-1349-y

ORIGINAL ARTICLE

Head CT scan in Iranian minor head injury patients: evaluating current decision rules Robab Sadegh 1 & Ehsan Karimialavijeh 2 & Farzaneh Shirani 2 & Pooya Payandemehr 3 & Hooman Bahramimotlagh 4 & Mahtab Ramezani 5

Received: 19 June 2015 / Accepted: 17 September 2015 / Published online: 25 September 2015 # American Society of Emergency Radiology 2015

Abstract The objective of this study is to select one of the seven available clinical decision rules for minor head injury, for managing Iranian patients. This was a prospective cohort study evaluating medium- or high-risk minor head injury patients presenting to the Emergency Department. Patients with minor head trauma who were eligible for brain imaging based on seven available clinical decision rules (National Institute for Health and Clinical Excellence (NICE), National Emergency X-Radiography Utilization Study (NEXUS)-II, Neurotraumatology Committee of the World Federation of Neurosurgical Societies (NCWFNS), New Orleans, American College of Emergency Physicians (ACEP) Guideline, Scandinavian, and Canadian computed tomography (CT) head rule) were selected. Subjects were underwent a non-contrast axial spiral head CT scan. The outcome was defined as abnormal and normal head CT scan. Univariate analysis and stepwise linear regression were applied to show the best combination of risk factors for detecting CT scan abnormalities. Five hundred patients with minor head trauma were underwent brain CT scan. The following criteria were derived by stepwise linear

* Ehsan Karimialavijeh [email protected] 1

Department of Emergency Medicine, Imam Khomeini Hospital, Tehran University of Medical Science, Tehran, Iran

2

Department of Emergency Medicine, Shariati Hospital, Tehran University of Medical Sciences, Kargar Ave., P.O. Box: 14117-13137, Tehran, Iran

3

Department of Emergency Medicine, Sina Hospital, Tehran University of Medical Sciences, Tehran, Iran

4

Department of Radiology, Sina Hospital, Tehran University of Medical Sciences, Tehran, Iran

5

Shahidbeheshti University of Medical Sciences, Tehran, Iran

regression: Glasgow Coma Scale (GCS) less than 15, confusion, signs of basal skull fracture, drug history of warfarin, vomiting more than once, loss of consciousness, focal neurologic deficit, and age over 65 years. This model has 86.15 % (75.33–93.45 %) sensitivity and 46.44 % (46.67–51.25 %) specificity in detecting minor head injury patients with CT scan abnormalities (95 % confidence interval). Of seven decision rules, only the Canadian CT Head Rule possesses seven of the eight high-risk factors associated with abnormal head CT results which were identified by this study. This study underlines the Canadian CT Head Rule’s utility in Iranian minor head injury patients. Our study encourages researchers to evaluate available guidelines in different communities. Keywords Head injury . Computed tomography . Decision modeling

Introduction Head trauma is considered a common complaint in the Emergency Department (ED). Each year, 1.7 million patients are referred to US EDs due to head trauma [1], of which most are diagnosed as minor head injury. Although minor head injury is common in Iran; unfortunately, the exact number is unknown. Minor head injury has been defined as Glasgow Coma Scale (GCS) 13–15 [2–4] or GCS equals 14 and 15 [5]. Computed tomography (CT) is a standard imaging for acute head injury. Disposition of head injured patients with GCS less than 14 is fairly straightforward, but there is some controversy regarding GCS equals 14 and 15, especially in ordering head CT scans for patients [3]. Up to 15 % of minor head injuries have serious abnormalities such as skull fractures, contusions, subarachnoid hemorrhage

10

(SAH), epidural hematoma (EDH), subdural hematoma (SDH), intraparenchymal hemorrhage (IPH), interventricular hemorrhage (IVH), herniation, and midline shift. Less than 1 % of cases need neurosurgical interventions such as ventriculostomy drain, intracranial pressure monitor, clot evacuation, subdural drain placement, craniotomy, or craniectomy [3, 4, 6–9]. Therefore, a head CT scan in all minor head trauma patients would not be reasonable, economically. Ionizing radiation will also lead to an increase in the risk of malignancy, and it is prudent to order a head CT scan only for certain cases (minor head injury patients who have a high likelihood of brain injury based on current clinical decision rules). Identification of high-risk minor head trauma patients is still a challenge for emergency physicians. Emergency physicians use evidence-based guidelines to manage patients suffering from minor head injury [10]. At least seven clinical decision rules have been developed to predict the need for a CT scan in patients suffering from mild head injury [3, 4, 11–14]. The National Institute for Health and Clinical Excellence (NICE) in the UK has published guidelines for CT imaging. NICE introduced the risk factors, including GCS score of 14, signs of basal skull fracture, neurologic deficit, vomiting, amnesia before impact greater than 30 min, posttraumatic seizures, coagulopathy, dangerous mechanism, and age over 64 years [10]. The Neurotraumatology Committee of the World Federation of Neurosurgical Societies (NCWFNS) has also proposed guidelines that include GCS score of 14, suspected skull fracture, neurologic deficit, vomiting, amnesia, loss of consciousness, headache, coagulopathy, previous neurosurgery, history of epilepsy, and alcohol or drug abuse [14]. Fabbri et al. [15] have applied the NICE and NCWFNS criteria to 7955 patients. Although NICE was less sensitive, it was more specific for identifying intracranial and neurosurgical lesions. NEXUS-II and the Scandinavian clinical decision rules are also highly sensitive and specific in the detection of high-risk minor head injuries [16]. Other accurate tools in minor head injury disposition are the New Orleans Criteria [3] and the Canadian CT Head Rule [1, 4]. The American College of Emergency Physicians (ACEP) has also published a clinical policy that establishes the best evidence for managing minor head injury patients [17]. These rules can lead to notable cost savings for health care and decreased hospitalization length and will minimize exposure to ionizing radiation [18]. However, these clinical decision rules are different based on clinical and demographic indicators for imaging [19]. We aim to identify which clinical decision rules are more compatible with Iranian patients.

Emerg Radiol (2016) 23:9–16

Methods This prospective cohort study was carried out on 500 patients to enroll medium- or high-risk minor head injury patients between 2013 and 2014. Minor head injury was defined as a patient with head trauma and GCS of 14–15 at presentation to the ED. Participants attended the three EDs including two urban trauma centers (1000-bed hospitals, one with 150,000, and the other with 120,000 ED visits each year) and one urban general hospital (500-bed hospital with 65,000 ED visits each year) in Iran. The medical system in Iran is nationally funded, and all three mentioned EDs use national health insurance. The exclusion criteria were as follows: patients less than 16 years old, GCS less than 14, penetrating head injury, trauma more than 24 h ago, refusal to undergo head CT scan (patients who were opting to be under close observation in the ED rather than undergoing brain imaging), unreliable history, low-risk mild head injury, and unstable vital signs. Eligible patients underwent a head CT scan. Low-risk patients were discharged after observation. For risk stratification of patients, risk factors that were included in seven available clinical decision rules were used (Table 1). The axial spiral head CT scan without contrast, including bone window, from the base of the skull to the vertex with 10-mm-thick cuts, was the only available imaging protocol for head injury at all mentioned EDs. We did not use 3-D reconstruction images in the study. An emergency medicine resident was assigned to follow up all patients by phone after 30 days, whether they were discharged from the ED or neurosurgery ward. She had access to the contact numbers of patients and at least two of their firstdegree relatives. In two cases, the follow-up was made by contact with the relatives rather than patients. No data were lost from following up. Outcomes of the study were as follows: (1) normal head CT scan and (2) abnormal head CT scan [linear-open-depressed or basal skull fracture, cerebral contusion, pneumocephalous, subarachnoid hemorrhage (SAH), epidural hematoma (EDH), subdural hematoma (SDH), intraparenchymal hemorrhage (IPH), interventricular hemorrhage (IVH), and midline shift]. From those with abnormal head CT results, a small subdivision of patients required neurosurgical intervention (ventriculostomy drain, intracranial pressure monitor, clot evacuation, subdural drain placement, craniotomy, and craniectomy or endotracheal intubation and death due to head injury, within 7 days). At first, an independent attending emergency physician interpreted the images. Then, an attending radiologist confirmed the reported findings as the gold standard. Confirmations were reported by the same attending radiologist. Acute Concussion Evaluation, ED Version 1.4, was used for database assembly [21]. All interpreters were blinded to the patients’ information. Data were analyzed using SPSS

Emerg Radiol (2016) 23:9–16 Table 1

11

Available clinical decision rules for minor head injury

Clinical Finding

ACEP Head CT Guideline

Canadian

New Orleans

NCWFNS

NEXUS-II

NICE

Scandinavian

GCS score

14, 15

<15 at 2 h

<15

<15

<15 at 2 h

<15

Amnesia

Any with LOC

Retrograde >30 min Anterograde Any (medium risk) Open, depressed, Any injury Any basal above clavicles

Abnormal alertness, behavior –

Suspected fracture Basilar skull fracture, any injury above the clavicles with LOC Vomiting Any Recurrent

Any

Any

Recurrent

Recurrent

–

>60

–

≥65

≥65

–

Coagulopathy

>60 with LOC, ≥65 without LOC Any

–

–

Any

Any

Any

Any

Focal deficit

Any

–

–

Any

Any

Any

Any

Seizure

Posttraumatic seizure with LOC –

–

Any

History

–

Any

Any

–

Age (years)

LOC Visible trauma Headache

≥65

Any

Retrograde Any >30 min Open, depressed, Basal, depressed, basal confirmed

Any injury above clavicles with LOC Sever

Injury mechanism Dangerous

If GCS=14

–

Any

–

–

Above clavicles

–

Scalp hematoma –

Any Multiple injuries

–

Severe

Any

–

–

–

–

–

–

Dangerous

–

Drug, alcohol

Abuse history –

–

–

–

Yes

–

–

Shunt

Intoxication

Drug, alcohol

Dangerous (medium risk) –

Previous neurosurgery

–

–

Source: [19, 20]

software (Version 22 for Windows; SPSS, Inc., Chicago, IL). We used the χ2 test to find a significant correlation between causes of trauma and an abnormal CT scan. The Kruskal–Wallis test was used to determine the correlation between age and cause of injury. The Mann– Whitney U test was used to determine the age distribution by positive or negative head CT scan. Univariate analysis was used to find out the association between each risk factor and an abnormal CT scan. P value less than 0.05 was considered as significant. Ultimately, stepwise linear regression was applied to show the best combination of risk factors for detecting CT scan abnormalities.

Results Of 500 medium- or high-risk minor head injury patients, 339 patients (67.8 %) were men and 161 patients (32.2 %) were women. The mean age was 37.08±14.48 years. The mean age of men was 37.32±14.33 years and that of women was 36.8± 14 years. There was no difference in age between men and women (p=0.644). Motor vehicle collision, at 118 cases (23.6 %), was the most common cause of head injury. Falling down, at 94 (18.8 %), and violence, at 86 (17.3 %), were other common causes, respectively (Table 2). The chi-square test did not show statistically significant correlation between cause of head injury and positive head

Table 2 Causes of head injury Cause of injury

Number of patients

Number of patients with abnormal head CT findings

Direct blow MVC Falling Violence Sport Other Total

74 (14.8 %) 118 (23.6 %) 94 (18.8 %) 86 (17.3 %) 47 (9.4 %) 81 (16.2 %) 500 (100 %)

9 (12.2 %) 15 (12.7 %) 13 (13.8 %) 10 (11.6 %) 6 (12.8 %) 12 (14.8 %) 65 (13 %)

MVC motor vehicle collision

12

Emerg Radiol (2016) 23:9–16

Fig. 1 Age distribution of patients based on different head injury causes

CT scan findings (p=0.99). The correlation between the age distribution of head injured patients and falling (p=0.05) was significantly higher than sport (p=0.01), violence (0.015), or any other cause of head injury (Fig. 1). There was no significant correlation between other causes of head injury and age. According to the Mann–Whitney U test, age distribution among patients with abnormal head CT scan findings was similar to those with normal head CT scans (p=0.1) (Fig. 2). Sixty-eight abnormal findings were reported in CT scans of 65 (13 %) minor head injury patients. Three patients concurrently had two findings (one patient had both EDH and linear skull fracture, while another two patients had SDH and midline shift). Among the positive findings, the most frequent abnormality was contusion, with 18 cases (26.47 %) (Table 3). The association between each variable (all documented clinical findings based upon the Acute Concussion Evaluation, ED Version 1.4, and available risk factors [21]) with abnormal head CT findings was evaluated by univariate

Fig. 2 Age distribution of patients based on abnormal and normal head CT scans

analysis. Table 4 shows the correlation of some important variables with positive head CT scans. Vomiting, loss of consciousness (LOC), confusion, seizure, rhinorrhea, Battle’s sign, FND, GCS equals 14, and warfarin use all had significant correlation with a positive CT scan. Based upon linear-by-linear association, a higher number of risk factors in a patient would increase the probability of an abnormal CT scan (p=0.001). Five patients needed neurosurgery intervention. Two of them had SDH, two patients had EDH, and one patient had a basal skull fracture with the persistent CSF leak (Table 5). GCS less than 15, confusion, signs of basal skull fracture, drug history of warfarin, vomiting more than once, loss of consciousness, focal neurologic deficit, and age over 65 years were derived by stepwise linear regression. The presence of any of the above criteria mandates performing a head CT scan for the patient. This model has 86.15 % (75.33 –93.45 %) sensitivity, 46.44 % (46.67 –

Abnormal CT scan

Normal CT scan

Emerg Radiol (2016) 23:9–16 Table 3 Frequency of CT scan findings

13

Head CT scan finding

Frequency

Depressed skull fracture

9 (13.2 %)

Linear skull fracture

5 (7.3 %)

Open skull fracture Basal skull fracture

1 (1.4 %) 2 (2.9 %)

Pneumocephalus

2 (2.9 %)

IVH

0

EDH SDH

9 (13.2 %) 7 (10.2 %)

SAH IPH

9 (13.2 %) 4 (5.8 %)

Discussion

Contusions

18 (26.4 %)

Midline shift Total

2 (2.9 %) 68 (100 %)

Table 4 Univariate correlation of risk factors with positive CT scan findings

51.25 %) specificity, 19.38 % (14.98–24.41 %) positive predictive value, and 95.73 % (92.06–98.03 %) negative predictive value in detecting minor head injury patients with CT scan abnormalities (95 % confidence interval).

In the present study, 65 (13 %) patients had CT scan abnormalities. This rate is higher than prior studies [4, 22–24]. As mentioned previously, only minor head injury patients who had one of the high-risk factors (based upon prior available decision rules) were included in our study. Thus, we reported a higher prevalence of abnormal head CT scans in minor head injury.

Clinical findings

Number

CT result positive

Positive CT odds ratio

CI (95 %)

p value

Nausea

−248 +252 −345 +155 −193 +307 −452 +48 −386 +48

28 (11/3 %) 37 (14/7 %) 36 (10/4 %) 29 (18/7 %) 24 (12/4 %) 41 (13/4 %) 52 (11/5 %) 13 (27/1 %) 50 (11/5 %) 15 (23/8 %)

1.35

0.79–2.87

0.261

1.98

1.16–3.36

0.012

1.08

0.63–1.86

0.766

2.86

1.42–5.74

0.003

2.41

1.26–4.63

0.008

−425 +9 −497 +3

60 (12/4 %) 5 (35/7 %) 63 (12/7 %) 2 (66/7 %)

3.94

1.27–12.16

0.017

13.7

1.12–154.16

0.033

−489 +11 −485 +15 −489 +11 −490 +10 −465 +35 15 (321) 14 (179)

63 (19/2 %) 2 (18/2 %) 61 (12/6 %) 4 (26/7 %) 60 (12/3 %) 5 (45/5 %) 61 (12/4 %) 4 (40 %) 57 (12/3 % ) 8 (22/9 %) 30 (9/3 %) 35 (19/6 %)

1.50

0.31–7.1

0.608

2.52

0.78–8.18

0.122

5.9

1.17–20.12

0.004

4.6

1.28–17.08

0.019

2.12

0.91–4.89

0.078

2/36

1.39–3.99

0.001

<65 (466) ≥65 (34) −447 +53 −485 +14 −488 +11

59 (12/7 %) 61 (17/6 %) 59 (13/2 %) 6 (11/3 %) 59 (12/2 %) 6 (42/9 %) 64 (13/1 %) 1 (9/1 %)

1.48

0.58–3.72

0.407

0.84

0.34–2.05

0.697

5.42

1.82–16.19

0.002

0.66

0.08–5.27

0.697

Vomiting Headache Loss of consciousness Confusion Seizure Rhinorrhea Otorrhea Raccoon eyes Battle sign FND Amnesia GCS=14 Age DHx of ASA DHx of warfarin DHx of Plavix − Absence, + presence

FND focal neurologic deficit, DHx drug history

14

Emerg Radiol (2016) 23:9–16

Table 5 Clinical and CT scan findings in patients who needed neurosurgical intervention

Frequency

Clinical finding

CT scan finding

1 (0.2 %) 2 (0.4 %) 2 (0.4 %)

Battle sign + rhinorrhea + recurrent vomiting GCS <15 + confusion + recurrent vomiting + age >65a GCS <15 + confusion + recurrent vomiting + LOC

Basal skull fracture SDH

a

One patient was taking 5 mg warfarin Q daily due to chronic atrial fibrillation

Like previous studies [3, 4, 22], the most common head CT scan finding in our study was brain contusion. Depressed skull fracture, SDH, and EDH were other common findings, respectively. In the present study, the following risk factors were proved to be statistically associated with an abnormal head CT scan: vomiting twice or more, history of loss of consciousness, confusion, history of seizure or seizure because of head trauma, rhinorrhea, Battle’s sign, focal neurologic deficit, and GCS equals 14. Headache was not correlated with an abnormal head CT scan. Some previous studies considered headache as a risk factor in minor head injury [3, 7, 24], while others did not report this relationship [4, 25, 26]. Rhinorrhea, otorrhea, Battle’s sign, raccoon’s eye, and hemotympanum are signs of basal skull fracture. In our study, only rhinorrhea and Battle’s sign were associated with an abnormal head CT scan. We did not examine hemotympanum. Raccoon’s eye and otorrhea were not significant risk factors for an abnormal head CT scan in our patients. Most of the previous studies considered these five signs of basal skull fracture as a unique risk factor in minor head injury [3, 4, 27]. Although confusion leads to the lower GCS score, we considered it as an independent risk factor. In the final regression model, confusion was related to an abnormal head CT scan. ACEP guidelines also recommend observation and reexamination in cases of confused minor head injury patients [8]. GCS less than 15 has been found to be a significant risk factor for brain injury in minor head trauma. Prior studies also considered this as a risk factor in minor head injury patients [28–31]. Gupta et al. suggested that Injury Severity Score (ISS), GCS, and occupant position are important variables in Table 6

EDH

assessing pretest clinical suspicion in head injury. They found that in front seat passengers with ISS greater than or equal to nine, or GCS less than or equal to 12, the likelihood of craniocerebral injury increased [32]. Richards et al. have reported that patients who had loss of consciousness were significantly more likely to have brain injury [33]. We considered any new posttraumatic neurologic complaint (motor abnormality, sensory abnormality, abnormal speech, visual change, and abnormal hearing) as focal neurologic deficit. Similar to previous studies, we also found that focal neurologic deficit is a significant risk factor for an abnormal head CT scan in minor head injury [14, 23, 27, 31, 34, 35]. The presence of seizure after head trauma or in the past medical history was a risk factor for an abnormal head CT scan. Some studies had excluded patients with seizure because they believed that any patient with seizure and head trauma should undergo brain imaging [2, 3, 35]. In our study, amnesia, headache, and single vomiting did not have significant association with an abnormal head CT scan [3, 4, 23, 36]. This may be due to our methodology, since, as mentioned before, we only performed a head CT scan in head injury patients who had risk factors. In this study, as the number of risk factors in a single patient was higher, the likelihood of finding an abnormality on the head CT scan was also higher. Although this is logical, it has not been mentioned previously [3, 4, 27, 37]. Our final model had 86.15 % (confidence interval (CI) 85.3–93.4 %) sensitivity and 46.44 % (CI 41.67–51.25 %) specificity for detecting patients with an abnormal head CT scan. It had a positive predictive value of 19.38 % (CI 14.98–

The compatibility of our risk factors with other clinical decision rules

Risk factors

ACEP

Canadian

New Orleans

NCWFNS

NEXUS-II

NICE

Scandinavian

GCS <15 Confusion Signs of basal skull fracture Coagulopathy (warfarin use) Vomiting >1 LOC Focal deficit Age >65

+ − + + − − + +

+ − + + + + + +

+ − − + − − + −

+ − − + − + + −

+ − − + + − + +

+ − + + + − + +

+ _ + + _ + + _

+ Compatible, − non-compatible

Emerg Radiol (2016) 23:9–16

24.41 %) and negative predictive value of 95.73 % (CI 92.06– 98.03 %). Our model could accurately detect all five patients (1 %) who needed a neurosurgical procedure. Sixty-one patients (12.2 %) were admitted to the neurosurgery ward, of whom five patients (1 %) underwent neurosurgical procedures (Table 5). We had no mortality among minor head trauma patients within 30 days. Stiell et al. (2001) reported that 1.4 % of minor head injuries needed neurosurgery. Similarly, Haydel et al. (2000) reported 0.4 % and Geijerstam and Brittonin (2003) reported that 0.9 % of minor head injured patients needed neurosurgery [3, 4, 37]. It seems that among the seven mentioned clinical decision rules, the Canadian CT Head Rule has more compatibility with our final combination of risk factors. The Canadian CT Head Rule includes five of the eight high-risk factors (GCS less than 15, sign of basilar skull fracture, vomiting more than once, LOC, and age over 65 years) associated with abnormal head CT results identified by this study. According to this rule, minor head injury patients with focal neurologic deficit and coagulopathy must undergo brain imaging [3]. Therefore, this rule covers seven of the eight criteria mentioned in our study (Table 6). There was not a significant correlation between amnesia or cause of the injury and abnormal head CT scan, while the Canadian CT Head Rule considers these as a medium risk for brain injury. NICE covers six of our risk factors (GCS less than 15, basal skull fracture, coagulopathy, vomiting more than once, focal neurologic deficit, and age over 65). The ACEP guidelines include five risk factors (GCS less than 15, coagulopathy, signs of basal skull fracture, age equal to or over 65 years, and focal neurologic deficit). According to the ACEP guidelines, a single episode of vomiting is a risk factor for brain injury. LOC must be with amnesia or age over 60 to be considered a risk factor. The NEXUS criteria include five of the eight risk factors (GCS less than 15, coagulopathy, vomiting more than once, focal neurologic deficit, and age over 65 years). The Scandinavian rule also includes five of the eight risk factors (GCS less than 15, basal skull fracture, coagulopathy, vomiting more than once, focal neurologic deficit, and age over 65 years). NCWFNS has four of the eight risk factors (GCS less than 15, basal skull fracture, coagulopathy, loss of consciousness, focal neurologic deficit). The New Orleans rule includes three of the eight risk factors (GCS less than 15, coagulopathy, and focal neurologic deficit). Thus, the Canadian CT Head Rule correlates more closely to the findings of this study than the other clinical decision models described.

15

CT protocols in the last 10 years use up to 5-mm thickness. The 10-mm-thick images will average data and reduce sensitivity for small foci of hemorrhage and non-displaced fractures. Though this may not have a significant clinical impact, it affects the number of abnormal reported findings.

Conclusion This study underlines the utility of the Canadian CT Head Rule in Iranian minor head injury patients. However, CT scan for head injury is common around the world and cost management in health care is of undisputed importance. Our study encourages researchers to evaluate available guidelines in different communities. Conflict of interest The authors declare that they have no conflict of interest.

References 1.

2.

3. 4. 5.

6.

7.

8.

9.

10.

Limitations

11.

The utilization of 10-mm-thick images, owing to lack of resources in our EDs, is the limitation of this study. Most head

12.

Morton MJ, Korley FK (2012) Head computed tomography use in the emergency department for mild traumatic brain injury: integrating evidence into practice for the resident physician. Ann Emerg Med 60(3):361–367 Stiell IG et al (2001) The Canadian CT Head Rule Study for patients with minor head injury: rationale, objectives, and methodology for phase I (derivation). Ann Emerg Med 38(2):160–169 Haydel MJ et al (2000) Indications for computed tomography in patients with minor head injury. N Engl J Med 343(2):100–105 Stiell IG et al (2001) The Canadian CT Head Rule for patients with minor head injury. Lancet 357(9266):1391–1396 Assieti R, Cazzaniga P, Carroli M (1996) Guidelines for minor head injured patients’ management in adult age. The Study Group on Head Injury of the Italian Society for Neurosurgery. J Neurosurg Sci 40(1):11–15 Fabbri A et al (2004) Prospective validation of a proposal for diagnosis and management of patients attending the emergency department for mild head injury. J Neurol Neurosurg Psychiatry 75(3): 410–416 Miller EC, Holmes JF, Derlet RW (1997) Utilizing clinical factors to reduce head CT scan ordering for minor head trauma patients. J Emerg Med 15(4):453–457 Jagoda AS et al (2009) Clinical policy: neuroimaging and decisionmaking in adult mild traumatic brain injury in the acute setting. J Emerg Nurs 35(2):e5–e40 Stiell IG et al (2005) Comparison of the Canadian CT Head Rule and the New Orleans Criteria in patients with minor head injury. JAMA 294(12):1511–1518 Jagoda AS et al (2008) Clinical policy: neuroimaging and decisionmaking in adult mild traumatic brain injury in the acute setting. Ann Emerg Med 52(6):714–748 Yates, D., N. Chater, P. Cooper, et al. (2007) Head injury: triage, assessment, investigation and early management of head injury in infants, children and adults, London Ingebrigtsen T, Romner B, Kock-Jensen C (2000) Scandinavian guidelines for initial management of minimal, mild, and moderate

16

13.

14.

15.

16.

17.

18.

19.

20.

21. 22.

23.

Emerg Radiol (2016) 23:9–16 head injuries The Scandinavian Neurotrauma Committee. J Trauma 48(4):760–766 Mower WR et al (2002) Developing a clinical decision instrument to rule out intracranial injuries in patients with minor head trauma: methodology of the NEXUS II investigation. Ann Emerg Med 40(5):505–514 Servadei F, Teasdale G, Merry G (2001) Defining acute mild head injury in adults: a proposal based on prognostic factors, diagnosis, and management. J Neurotrauma 18(7):657–664 Fabbri A et al (2005) Clinical performance of NICE recommendations versus NCWFNS proposal in patients with mild head injury. J Neurotrauma 22(12):1419–1427 Stein SC et al (2009) A critical comparison of clinical decision instruments for computed tomographic scanning in mild closed traumatic brain injury in adolescents and adults. Ann Emerg Med 53(2):180–188 Jagoda AS et al (2008) Clinical policy: neuroimaging and decisionmaking in adult mild traumatic brain injury in the acute setting. Ann Emerg Med 52(6):714–748 Sodickson A et al (2009) Recurrent CT, cumulative radiation exposure, and associated radiation-induced cancer risks from CT of adults. Radiology 251(1):175–184 Stein SC et al (2009) A critical comparison of clinical decision instruments for computed tomographic scanning in mild closed traumatic brain injury in adolescents and adults. Ann Emerg Med 53(2):180–188 Morton MJ, Korley FK (2012) Head computed tomography use in the emergency department for mild traumatic brain injury: integrating evidence into practice for the resident physician. Ann Emerg Med 60(3):361–367 Gerard Gioia, M.C.; Available from: http://www.cdc.gov/ concussion/headsup/pdf/ACE-a.pdf. af Geijerstam, J.L. and M. Britton (2003) Mild head injury—mortality and complication rate: meta-analysis of findings in a systematic literature review. Acta Neurochir (Wien) 145(10): p. 843-50; discussion 850 Borczuk P (1995) Predictors of intracranial injury in patients with mild head trauma. Ann Emerg Med 25(6):731–736

24.

25. 26.

27.

28. 29. 30. 31.

32. 33.

34.

35. 36.

37.

Clement CM et al (2006) Clinical features of head injury patients presenting with a Glasgow Coma Scale score of 15 and who require neurosurgical intervention. Ann Emerg Med 48(3):245–251 Smits M et al (2007) Minor head injury: guidelines for the use of CT—a multicenter validation study 1. Radiology 245(3):831–838 Ono K et al (2007) Indications for computed tomography in patients with mild head injury. Neurol Med Chir (Tokyo) 47(7):291–297, discussion 297-8 Bouida W et al (2013) Prediction value of the Canadian CT Head Rule and the New Orleans Criteria for Positive head CT scan and acute neurosurgical procedures in minor head trauma: a multicenter external validation study. Ann Emerg Med 61(5):521–527 Khaji A et al (2006) The use of head CT scanning in mild head injury. Neuroscience 11(4):248–251 Culotta VP et al (1996) Clinicopathological heterogeneity in the classification of mild head injury. Neurosurgery 38(2):245–250 Borczuk, P. (1997) Mild head trauma. Emergency Medicine Clinics of North America 15(3): p. 563-579 Murshid W (1998) Management of minor head injuries: admission criteria, radiological evaluation and treatment of complications. Acta Neurochir 140(1):56–64 Gupta R et al (2005) Head CT evaluation in clinically stable motor vehicle collision patients. Emerg Radiol 11(6):328–335 Wu SR et al (2006) Combined head and abdominal computed tomography for blunt trauma: which patients with minor head trauma benefit most? Emerg Radiol 13(2):61–67 Gómez PA et al (1996) Mild head injury: differences in prognosis among patients with a Glasgow Coma Scale score of 13 to 15 and analysis of factors associated with abnormal CT findings. Br J Neurosurg 10(5):453–460 Sacco F et al (2003) Guidelines for the management of head injuries in remote and rural Alaska. Alaska Med 46(3):58–62 Saboori M, Ahmadi J, Farajzadegan Z (2007) Indications for brain CT scan in patients with minor head injury. Clin Neurol Neurosurg 109(5):399–405 af Geijerstam, J.-L. and M. Britton (2003) Mild head injury—mortality and complication rate: meta-analysis of findings in a systematic literature review. Acta neurochirurgica 145(10): p. 843-850