Emerg Radiol DOI 10.1007/s10140-014-1234-0
ORIGINAL ARTICLE
Appropriateness of selection criteria for CT examinations performed at an emergency department Idil Gunes Tatar & Hasan Aydin & Volkan Kizilgoz & Kerim Bora Yilmaz & Baki Hekimoglu
Received: 18 February 2014 / Accepted: 4 May 2014 # Am Soc Emergency Radiol 2014
Abstract In the diagnosis of traumatic and nontraumatic emergencies, computed tomography (CT) is the most frequently performed procedure. The aims of this study were to find out whether CT report results can be used as a reliable tool for the diagnosis and management of patients at an emergency department and to evaluate the appropriateness of the selection criteria for CT examinations. For this reason, we analysed the emergency CT procedures according to the diagnostic hypothesis written on CT request forms, the results of the CT reports and the final diagnosis of the patients. One thousand consecutive CT procedures in the emergency department of a research hospital were retrospectively analysed. When the CT reports and the final diagnosis were evaluated, the sensitivity and specifity of the CT were found to be 0.81 and 0.85. According to the analysis of the CT reports, 55.8 % of all the patients were reported to be normal. When the patient files were examined for the final diagnosis of the patients, 55.7 % of the patients did not receive a final diagnosis related to the diagnostic hypothesis. The lowest correlation was found between the diagnostic hypothesis, the CT reports and the final diagnosis of the patients who underwent cranial CT procedure for trauma. The results of the CT reports can be used as a reliable parameter for the diagnosis and management of the patients at emergency departments. On the other hand, a high negative rate of CT reports was noted especially for the cranial CT examinations. CT selection criteria for the head trauma patients should be reconsidered. Since CT is a procedure involving ionising radiation, it is important that it is I. Gunes Tatar (*) : H. Aydin : V. Kizilgoz : B. Hekimoglu Department of Radiology, Diskapi Yildirim Beyazit Training and Research Hospital, 06110 Diskapi-Altındag/Ankara, Turkey e-mail:
[email protected] K. B. Yilmaz Department of General Surgery, Diskapi Yildirim Beyazit Training and Research Hospital, 06110 Diskapi-Altındag/Ankara, Turkey
performed with the correct indications and the relevant clinical information is specified on the CT request forms. Keywords Computed tomography . Trauma . Emergency department . Diagnostic hypothesis . Correlation
Introduction In the management of patients who are admitted to the emergency department, computed tomography (CT) has a significant role. In the diagnosis of trauma patients and nontraumatic emergencies, it is the most frequently performed imaging technique [1, 2]. With the advances in multidetector row technology, the CT examinations have started to take very short examination time [3]. Moreover, it has been possible to scan large body parts with thin slices and high resolution, to create reformatted and three-dimensional images and to use advanced imaging techniques when necessary [4–8]. There are studies indicating that the time spent between the patient’s entrance to the emergency department and the CT unit significantly affects the early diagnosis hence the result of the treatment [9, 10]. For this reason, in many hospitals, CT units are situated inside or very close to the emergency departments facilitating fast and easy access in medical emergencies [11, 12]. On the other hand, it should always be kept in mind that CT is a diagnostic procedure using ionising radiation, thus its usage must be justified and optimised. Our hypothesis is that CT report results can be used as a reliable tool for the diagnosis and management of patients in emergency departments. The aims of this study were to find out the sensitivity and specificity of CT report results and to evaluate the appropriateness of selection criteria for CT examinations at an emergency department. For this reason, we analysed the CT examinations performed at an emergency unit
Emerg Radiol
in terms of information written on the CT request forms, CT reports and the final diagnosis of the patients.
Material and methods After obtaining the approval of the ethical committee, a retrospective research was done on 1,000 consecutive CT examinations performed at the emergency unit of a major research hospital. The data was collected during November and December 2010. At first, CT examination request forms were analysed according to the diagnostic hypothesis, defined as the preliminary potential diagnosis written on the CT examination request forms by the doctor at the emergency unit, and patient subgroups were formed. Secondly CT reports of the radiologists were analysed according to the presence or absence of a positive finding related to the diagnostic hypothesis. Thirdly the patient files were examined to find out whether the patients received a final diagnosis related to the diagnostic hypothesis written on the CT examination request forms. Sex and age of all patients were also searched from the medical records. For the CT examinations, Hitachi Pronto 2006 model spiral tomography was used. SPSS for Windows 15 programme was used for statistical analysis. The statistical relationship between the CT report results and the final diagnosis was analysed by the chi-square test, with the exception of paranasal CT and temporal CT subgroups which have low predicted frequencies where Fisher’s chi-square test was used. P<0.05 was accepted as a significant relationship. The sensitivity and specificity of the CT reports were calculated according to the final diagnosis of the patients. Also, the correlation between the diagnostic hypothesis written on the CT examination request forms and CT reports was analysed. The false positivity rates of the diagnostic hypothesis were evaluated in comparison with the final diagnosis of the patients.
Results Analysis of the 1,000 consecutive CT procedures revealed 488 (48.8 %) cranial, 120 (12 %) vertebral, 115 (11.5 %) abdominal, 105 (10.5 %) bone, 97 (9.7 %) thorax, 39 (3.9 %) paranasal, 31 (3.1 %) temporal, and 5 (0.5 %) maxillofacial examinations. The mean age of the patients was 45.45 ±19.45; range 15–97. In the patient group, 536 (53.6 %) patients were males and 464 (46.4 %) patients were females. Among the 488 cranial CT examinations, 205 (42 %) were performed for trauma, 108 (22.1 %) for headache, 37 (7.6 %) for cerebrovascular event, 86 (17.6 %) for other diagnostic hypotheses such as syncope, epilepsy, and vertigo. Out of the 488 cranial CT examinations, on 52 (10.6 %) forms no diagnostic hypothesis was written. When CT reports were
examined, 21 % of the trauma cases, 33 % of the headache cases, 38 % of the cerebrovascular event cases, 31 % of the other cases received a positive finding in the CT report related to the diagnostic hypothesis. Twenty-five percent of the patients without a diagnostic hypothesis also had a positive finding in the CT report. When CT reports were correlated to the final diagnosis of the patients, the sensitivity and specifity of the CT examination were 0.95 and 0.96 for trauma (P=0.001); 0.84 and 0.93 for headache (P=0.001); 0.57 and 0.88 for cerebrovascular event (P=0.006); 0.69 and 0.94 for others (P=0.001) and 0.79 and 0.95 for cases without a diagnostic hypothesis (P=0.001). For the 120 vertebral CT examinations, 53 (44.2 %) of the diagnostic hypothesis were trauma, 58 (48.3 %) were others such as spondylosis and discopathy. On nine (7.5 %) forms, no diagnostic hypothesis was written. When CT reports were examined, 36 % of the trauma cases and 48 % of the other cases had a positive finding in the CT report related to the diagnostic hypothesis. In 56 % of the patients without a diagnostic hypothesis, a positive finding was also identified in the CT report. When CT reports were correlated to the final diagnosis of the patients, the sensitivity and specifity of the CT examination were 0.71 and 0.88 for trauma (P=0.001) and 0.89 and 0.70 for other diagnostic hypotheses (P=0.001). The cases without a diagnostic hypothesis did not have a statistically significant correlation (P=0.643). When the 115 abdominal CT examinations were analysed, 78 (67.8 %) cases were requested for urolithiasis, 24 (20.9 %) cases for trauma and 9 (7.8 %) cases for acute abdomen. On four (3.5 %) forms, no diagnostic hypothesis was written. When CT reports were examined, 65 % of the urolithiasis cases, 50 % of the trauma cases and 67 % of the acute abdomen cases had a positive finding in the CT report related to the diagnostic hypothesis. In 50 % of the cases without a diagnostic hypothesis, there was a positive finding in the CT report. When CT reports were correlated to the final diagnosis of the patients, the sensitivity and specifity of the CT examination were 0.88 and 0.70 for urolithiasis cases (P=0.001) and 0.71 and 0.80 for trauma cases (P=0.018). The acute abdomen cases and cases without a diagnostic hypothesis did not have a statistically significant correlation (P=0.538 and P= 0.833, respectively). Among the 105 CT examinations performed for bones, 69 (65.7 %) were done for trauma and 29 (27.6 %) for soft tissue disorders. On seven (6.7 %) forms, no diagnostic hypothesis was written. When CT reports were examined, 78 % of the trauma cases and 52 % of the soft tissue disorders received a positive finding in the CT report related to the diagnostic hypothesis. Forty-three percent of the cases without a diagnostic hypothesis had a positive finding in the CT report. When CT reports were correlated to the final diagnosis of the patients, the sensitivity and specifity of the CT examination were 0.90 and 0.56 for trauma (P=0.001) and 0.79 and
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0.73 for soft tissue disorders (P=0.007). The cases without a diagnostic hypothesis did not have a statistically significant correlation (P=0.629). For the 97 thorax CT examinations, 17 (17.5 %) of the diagnostic hypothesis were trauma; 11 (11.3 %) were chest pain emergencies such as emboli and dissection and 35 (36 %) were others such as chronic obstructive lung disease, coughing and infection. On 34 (35 %) forms, no diagnostic hypothesis was written. When CT reports were examined, 76 % of the trauma cases; 36 % of the chest pain emergencies and 71 % of the others such as chronic obstructive lung disease, coughing and infection had a positive finding in the CT report related to the diagnostic hypothesis. In 65 % of the patients without a diagnostic hypothesis, a positive finding was identified in the CT report. When CT reports were correlated to the final diagnosis of the patients, the sensitivity and specifity of the CT examination were 0.88 and 0.70 for chronic obstructive lung disease, coughing and infection (P=0.002) and 0.87 and 0.82 for patients without a diagnostic hypothesis (P=0.001). The trauma cases and chest pain emergencies did not have a statistically significant correlation (P=0.121 and P=0.652, respectively). When the 39 paranasal sinus CT examinations were analysed, five (12.8 %) cases were requested for trauma and 28 (71.8 %) cases for sinusitis. On six (15.4 %) forms, no diagnostic hypothesis was written. When CT reports were examined, 40 % of the trauma cases and 75 % of the trauma cases had a positive finding in the CT report related to the diagnostic hypothesis. In 50 % of the cases without a diagnostic hypothesis, there was a positive finding in the CT report. When CT reports were correlated to the final diagnosis of the patients, the sensitivity and specifity of the CT examination were 0.90 and 0.63 for sinusitis cases (P=0.009). The trauma cases and cases without a diagnostic hypothesis did not have a statistically significant correlation (P=0.700 and P=0.500, respectively). Among the 31 temporal CT examinations, 6 (19.3 %) were done for trauma and 25 (80.6 %) for otitis and hearing loss. When CT reports were examined, 67 % of the trauma cases and 64 % of the otitis and hearing loss cases received a positive finding in the CT report related to the diagnostic hypothesis. When CT reports were correlated to the final diagnosis of the patients, there was not a statistically significant correlation (P=0.800 and P=0.053, respectively). Since only five maxillofacial CT examinations were performed, it was not meaningful to evaluate this section as a subgroup. The correlation between the diagnostic hypothesis on the CT examination request forms and CT reports was summarised according to the subgroups and for all patients (Table 1). The correlation between the CT reports and the final diagnosis of the patients was outlined according to the subgroups (Table 2) and for the all patients (Table 3).
Table 1 The distribution of the CT reports according to the CT examination types Examination
CT report Positive
Cranial CT Vertebral CT Abdominal CT Bone CT Thorax CT Paranasal sinus CT Temporal bone CT Maxillofacial CT Total
Negative
Total
n
%
n
%
n
134 52 71 72 64 26 20 3 442
27 43 62 69 66 67 65 60 44
354 68 44 33 33 13 11 2 558
73 57 38 31 34 33 35 40 56
488 120 115 105 97 39 31 5 1,000
CT computed tomography, n number of CT reports
Discussion The high sensitivity (0.81) and specificity (0.85) values found in this research support the significant role of CT at emergency departments (P<0.05). The results of the CT reports can be used as a reliable parameter for the diagnosis and management of the patients at emergency departments. On the other hand, a high negative rate of the CT reports was noted. When reports of the CT examinations are examined, 55.8 % of all the reports were normal. Cranial CT was the group with the highest discordance since 73 % of the cranial CT reports were normal. In this group, trauma subgroup has the highest disagreement; 79 % of the reports being normal. When the final diagnosis of the patients were investigated, 55.7 % of the patients did not have a final diagnosis related to the diagnostic hypothesis on the CT request forms. Cranial CT examinations showed the highest conflict as 70 % of the patients did not receive a final diagnosis related to the diagnostic hypothesis on the CT request forms. In this group, trauma was the subgroup with the highest discordance; 81 % of the trauma patients not having a relevant final diagnosis. These results suggest that the CT selection criteria for the head trauma patients should be reconsidered. In the literature, there are studies investigating the appropriateness of the CT selection criteria of the patients with head trauma according to the National Institute of Clinical Excellence (NICE) criteria. A Glasgow Coma Score (GCS) lower than 13 at any time after trauma, GCS of 13 or 14 two hours after the trauma, focal neurological deficit, suspicion of open or displaced cranial bone fracture, posttraumatic seizure, any sign of fracture at the base of the cranium, more than one episode of vomiting after the trauma, loss of consciousness in patients who are above 65 years old, coagulopathy, retrograde amnesia for more than 30 min and high-speed trauma are the
Emerg Radiol Table 2 The correlation between the CT reports and the final diagnosis of the patients according to CT examination types Examination
Final diagnosis
Cranial CT
CT report
Vertebra CT
Total CT report
Abdominal CT
Total CT report
Bone CT
Total CT report
Thorax CT
Total CT report
Paranasal sinus CT
Total CT report
Temporal bone CT
Total CT Report
Positive Negative Positive Negative Positive Negative Positive Negative Positive Negative Positive Negative Positive
Total
Sensitivity
Specificity
P value
0.79
0.94
0.001*
0.77
0.75
0.001*
0.82
0.70
0.001*
0.86
0.64
0.001*
0.82
0.72
0.001*
0.84
0.64
0.003*
0.78
0.54
0.076
Positive
Negative
115 31
19 323
134 354
146 33 10 43 58 13 71 59 10 69 56 12 68 21 4 25 14
342 19 58 77 13 31 44 13 23 36 8 21 29 5 9 14 6
488 52 68 120 71 44 115 72 33 105 64 33 97 26 13 39 20
CT computed tomography, n number of CT reports *P<0.05
CT selection criteria [13]. The NICE criteria depend on investigations with large scales. A prospective research with large cohort conducted at the emergency departments of 10 Canadian hospitals was used to determine the NICE criteria [14]. The adults who had head trauma with GCS of 13–15 were analysed in this study. Eight percent of the patients were diagnosed with clinically significant head trauma, and 1 % of the patients required neurosurgery. According to the results, a series of symptoms and risk factors that can be used to predict the sequela which can appear following head trauma were proposed. With these factors, NICE criteria were formed. In Great Britain, 600,000–700,000 patients per year are expected to present to the emergency departments with head trauma [15]. The majority of these cases are (70–80 %) minor Table 3 The correlation between the CT reports and the final diagnosis of the patients
Final diagnosis
CT report
Total *P<0.05
trauma; about 4,000 patients necessitate neurosurgical procedures [16]. Harris et al. conducted a research to investigate the compliance to the NICE criteria and the number of the CT examinations in patients with minor head trauma for a period of 6 months. Based on the NICE criteria, 88 of the 844 minor trauma patients were appropriate for cranial CT examination, but only 10 patients underwent CT examination [17]. Authors concluded that in case of adherence to the NICE criteria, the number of CT examinations would show a ninefold increase. The authors concluded that the low numbers of CT examinations performed could be due to the high cost of CT procedures, the lack of sufficient doctors for follow-up and the burden of the long hospitalisation time on the healthcare system.
Positive
Negative
Total
Sensitivity
Specificity
P value
0.81
0.85
0.001*
Positive
n %
358 81.0
84 19.0
442 100.0
Negative
n % n %
85 15.2 443 44.3
473 84.8 557 55.7
558 100.0 1.000 100.0
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In a similar research done by Macgregor and Mckie, among 537 children with head trauma, 62 were found to be appropriate for the CT selection criteria, but only eight patients were referred for CT [18]. Only 1 of those eight patients had a pathology identified by CT. The results put forward that if the NICE criteria were strictly followed, eight time more patients would have undergone CT procedure. The authors emphasised the importance of clinical evaluation for CT selection criteria in children to minimise their radiation exposure to explain the low number of CT examinations. A research carried out by Novak et al. demonstrated similar results to ours. In the retrospective analysis of 367 cranial CT examinations in terms of diagnostic hypothesis and CT reports, 50.4 % of the CT reports were found to be normal [19]. The groups with the highest correlation were ruling out lesions (66.7 %), hydrocephalus (50 %), ischemic stroke (50 %) and hematoma (50 %). The authors highlighted the importance of detailed clinical information on CT request forms to help the radiologist’s report. In our research, bone CT examination group was the group with the highest correlation between the diagnostic hypothesis on the CT request forms and CT reports. This can be explained by the more objective nature of physical examination or the more suitable patient selection for CT with the help of other preliminary imaging modalities such as X-rays in musculoskeletal system. A medical approach is justified if the expected benefit is more than its potential harm. When radiologic examinations are considered, the presence of a rightful reason is enforced by the laws [20, 21]. Medical procedures using ionising radiation must be justified and optimised. According to the radiation protection laws, the doctor requesting the examination is responsible for the rightful reason and transmission of the detailed clinical information of the patient. It is the duty of the radiologist to give the last decision for a requested examination considering its benefit versus the radiation dose, choosing the suitable protocols and dose-decreasing techniques [22–24]. The goals of this procedure are to prevent the unnecessary radiation dose of the population as well as to promote the quality of the diagnostic reports. The limitations of the study were the retrospective design and the lack of long-term follow-up of the patients. Since the patients were not followed up prospectively, the final diagnosis indicated in the patient files at discharge from the hospital was taken into account.
Conclusion The results of the CT reports can be used as a reliable parameter for the diagnosis and management of the patients at emergency departments. On the other hand, a high negative rate of CT reports was noted especially for the cranial CT
examinations. CT selection criteria for the head trauma patients should be reconsidered. Since CT is a procedure involving ionising radiation, it is also substantial to choose the correct indications and to specify the relevant clinical information on the CT request forms.
Conflict of interest The authors declare that they have no conflict of interest.
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