Clinical Imaging xxx (2014) xxx–xxx
Contents lists available at ScienceDirect
Clinical Imaging journal homepage: http://www.clinicalimaging.org
Multidetector computed tomography (MDCT): simple CT protocol for trauma patient Katrin Eichler a,⁎, Ingo Marzi b, Hendrik Wyen b, Stephan Zangos a, Martin G. Mack c, Thomas J. Vogl a a b c
Department of Diagnostic and Interventional Radiology University of Frankfurt, Germany Department of Trauma, Hand and Reconstructive Surgery University of Frankfurt, Germany Radiology Munich, Munich, Germany
a r t i c l e
i n f o
Article history: Received 13 March 2014 Received in revised form 9 September 2014 Accepted 12 September 2014 Available online xxxx Keywords: MDCT Polytrauma Fixed venous protocol Image quality
a b s t r a c t The purpose of this retrospective monocenter study was to evaluate a monophasic multidetector computed tomography (MDCT) protocol with a fixed delay for patients with polytrauma. A total of 2086 patients were evaluated retrospectively. For the intravenous contrast media, we used a fixed protocol with an injection for an adult patient of 120 mL at a rate of 2 mL/s. In the venous phase, we detected injuries of parenchyma and localized ongoing bleedings in regard to the clinical follow-up, with regard to the easy feasibility and the quickness with only one scan. Monophasic venous injection protocol can detect all injuries in the wholebody MDCT for patients with polytrauma. © 2014 Elsevier Inc. All rights reserved.
1. Introduction For initial evaluation of patients with multiple injuries, multidetectorrow computed tomography (MDCT) is considered a reliable accurate imaging modality. Radiologists constantly attempt to devise new ways to reduce the amount of time needed to adequately image trauma victims while simultaneously improving image quality [1]. The availability of MDCT in many trauma centers makes it the imaging modality of choice for the evaluation of multitrauma patients, defined as those who suffer from injuries to multiple organs, skeletal system, or vascular system obtained during a single event, in which one or more of the injuries are potentially life threatening [2]. An effective CT protocol must represent the best trade-off between high diagnostic image quality, reconstruction processing, and a short acquisition time. Both examination speed and increasing concern about the radiation dose applied necessitate one spiral acquisition instead of multiple different phases [3]. A delay in proper surgical care is a major cause for preventable deaths in trauma care, and the earliest possible identification of potential lethal injuries is mandatory for optimal trauma care [4]. Therefore, rapid depiction and therapy of injuries which can cause fatal outcome in the first 24 h after trauma are mandatory [5]. Different lesions, like hematoma and ongoing hemorrhage and parenchyma contusion or laceration of multiple organs, have to be ⁎ Corresponding author. Institute for Diagnostic and Interventional Radiology, J. W. Goethe University of Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt. Tel.: +49 69 6301 87288; fax: +49 69 6301 7288. E-mail address: [email protected] (K. Eichler).
depicted, often evaluated with a biphasic injection protocol [6]. In most cases, the administration of contrast medium for an arterial phase is difficult because bolus tracking is often inadequate following multiple trauma on account of the circulatory instability present [7]. The hypothesis of our paper is that a very simple monophasic CT monophasic protocol can depict all relevant anatomy and all pathologies.
2. Materials and methods 2.1. Patients and methods Two thousand eighty-six patients (1492 men and 594 women) with polytrauma in the last 5 years with a whole-body imaging were evaluated retrospectively. The CT scanner was located directly in the trauma resuscitation room. Before the introduction of MDCT in our trauma algorithm, conventional radiography of the pelvis and chest in combination with focused assessment with sonography for trauma was the diagnostic measure. After the scans have been completed, the algorithm continued with the necessary emergency interventions. In the meantime, the acquired data of the CT scans were processed and evaluated by a staff radiologist. The findings on the CT scan and the patient's condition determined the further procedure. So, the patient could be transferred to the operating room, to an intensive care unit, home, or to a regular surgical ward. The study was performed according to the regulations of the local ethics committee for retrospective studies and was approved by the institutional review board.
http://dx.doi.org/10.1016/j.clinimag.2014.09.011 0899-7071/© 2014 Elsevier Inc. All rights reserved.
Please cite this article as: Eichler K, et al, Multidetector computed tomography (MDCT): simple CT protocol for trauma patient, Clin Imaging (2014), http://dx.doi.org/10.1016/j.clinimag.2014.09.011
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K. Eichler et al. / Clinical Imaging xxx (2014) xxx–xxx
2.2. Scanner All examinations were performed on a 16-slice MDCT system (Sensation 16; Siemens, Forchheim, Germany) with a collimation of 16×1.5 mm and a reconstruction slice thickness of both 2 and 5 mm. For normal-sized patients, a voltage of 120 kV was used. To optimize the current (mA) relative to body attenuation, the protocol used the Real-time Anatomic Exposure Control (CARE) dose 4D automatic exposure control (Siemens, Forchheim, Germany). The reference dose can only be set to one reference value for one acquisition. There are existing guidelines for the use of CT in pediatric patients from the European Union and the Food and Drug Administration [8]. With help of dose-saving mechanisms, modern CT scanners adapt the tube current to the examined volume and density of the body to reduce the effective dose. In addition, special pediatric scan protocols adapt the scan parameters to the smaller body diameters. The dose of the contrast medium (Iomeprol; Imeron 400, 400 mg/ml iodine; Altana, Konstanz, Germany) was calculated according to the patient's body weight (ml/kg body weight) and then injected intravenously in the antecubital vein at a flow rate of (ml/s) using a dual-head power injector (Injectron CT; Medtron, Saarbrücken, Germany) (Table 1). If the patient name is not known, a consecutively numbered and “no-name” emergency registration ID is used for the picture archive system and radiology information system. 2.2.1. Scanning protocol: head and cervical spine CT Head and cervical spine/neck scans were planned on a first scout and scanned without administration of intravenous contrast medium. The technologist has to search for items that could result in unwanted artifacts in the imaging study. These could range from necklaces and earrings to braids or other items on the patient's body. These should be removed before the examination. We first do a cranial spiral CT scan including the cervical vertebrae scan without intravenous contrast medium. The initial images should be analyzed at the CT console parallel to the positioning of the arms along the body. Findings are directly communicated to the neurosurgeons, the head of the trauma team, and the anesthesiologist. We use 120 kV, effective mA level of 300, rotation time of 1 s, pitch of 1, and a collimation of 16*0.75 mm. Thin slices of 1.0 mm reconstructed at 0.5-mm recon increment was obtained for bone window using the H70 very sharp kernel. Thicker slices of 5.0 mm should be reconstructed at 5-mm recon increment using the soft tissue kernel the H40 kernel medium and slices of 3.0mm should be reconstructed at 3-mm intervals using the H70 kernel. All images should are free of motion and include anatomy
Table 1 Amount of contrast medium in dependence of the weight on the patient Weight (kg)
Volume (ml)
Flow (ml/s)
Delay (s)
Jod, (gr.) absolut
5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 N100
14 19 28 37 46 56 65 74 83 93 102 111 120 120 120 120 120 120 120 120 120
0.23 0.31 0.46 0.62 0.77 0.93 1.08 1.23 1.39 1.54 1.70 1.85 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00
80 80 80 80 85 85 85 85 85 85 85 85 85 85 85 85 85 85 85 85 85
5.55 7.4 11.1 14.8 18.5 22.2 25.9 29.6 33.3 37 40.7 44.4 48.1 48.1 48.1 48.1 48.1 48.1 48.1 48.1 48.1
from the top of the skull through the end of the cervical vertebra. Sagittal and coronal multiplanar reconstructions (MPRs) were obtained using the bone window using distance of 2 mm and thickness of 2 mm. For the coronal MPR, we used the curved reconstruction. 2.2.2. Chest abdomen, pelvis, and spinal column CT acquisition was started at the middle of the seventh cervical spinal column and ended at the proximal femur. The arms were positioned over the head. Infusion lines, monitoring cables, and resuscitation tubes exit at the foot end. Prior the injection of iodinated contrast material, every iv access should be checked with an injection of at least 10 ml of saline. Any iv access that does not seem adequate for injection should not be used. Poor iv access can be a challenging pitfall in MDCT examinations because obtaining iv access in trauma patients can be difficult due to positioning. Trauma patients may have decreased iv access due to fractures, active bleeding, or poor vein patency. The contrast medium was administered via an 18-G peripheral access by means of an automated pump injector using a fixed injection protocol. For all injections in this study, the same injection device was used (Injectron CT; Medtron, Saarbrücken, Germany). For the injection of contrast media, we used a fixed protocol with an injection for an adult patient of 120 ml at a rate of 2 ml/s of a contrast medium containing 400 mg/ml iodine (Iomeprol; Imeron 400, 400 mg/ml iodine; Altana, Konstanz, Germany) followed by 60 ml NaCL at a rate of 2 ml/s. The body weights in adult patients and the renal clearances of the patients and their history of possible reactions to contrast material were not known at the time of the examination. Eighty-five seconds after the beginning of the injection, the CT acquisition was started. Delayed imaging in a low-dose technique to detect pelvicalyceal or disruption of the ureter was only performed in patients with damage in the kidneys in the venous phase. Images are reconstructed using soft tissue, bone, and lung windows. In the soft tissue window, images are reconstructed using 5-mm slice thickness with 5-mm intervals and a B30 medium smooth kernel. In the lung window, images are generated using a 5-mm slice thickness reconstructed at a 5-mm recon increment using the B60 sharp kernel. The bone window reconstructions are generated using a 2-mm slice thickness at 1-mm recon increment using the B70 very sharp kernel. Sagittal and coronal MPRs are obtained using the bone and soft tissue windows. For the sagittal and curved coronal reconstructions, we use a distance of 2 mm and a thickness of 3 mm. A radiologist with at least 3-year experience immediately makes the results. The results are checked and also released on the same day or subsequent day by a senior physician. 3. Results Two thousand eighty-six consecutive patients with a median age of 39.7 years (range, 1–96 years) including 1492 men and 594 women were evaluated retrospectively in a 5-year interval. Nine hundred sixty-eight patients had an Injury Severity Score (ISS) over 15. In 1934 (92.7%), it was a blunt injury; in 152 (7.3%), it was a penetrating injury. The causes divide themselves as follows: accident: 1854; suicide, 96; violence, 89; jump fall N 3 m, 283; jump fall b 3 m, 417; traffic accident: 996; pedestrian, 206; car, 406; motor bike, 201; bicycle, 183. 3.1. Thoracictrauma We evaluated 611 patients with thorax trauma with an average ISS of 32.5 (range, 4–75). Five hundred forty-four patients had an ISS over 15 (average, 35.5; range, 16–75). Abbreviated Injury Scale (AIS) 3= 198, 4=279, 5=64, and 6=2.
Please cite this article as: Eichler K, et al, Multidetector computed tomography (MDCT): simple CT protocol for trauma patient, Clin Imaging (2014), http://dx.doi.org/10.1016/j.clinimag.2014.09.011
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3.2. Injury categories We detected in 204 patients a rib fracture, in 295 patients a lung contusion, in 251 a pneumothorax, in 84 patients a hemothorax, in 14 patients a vascular injury, and in 15 patients another category. We detected two active bleedings from an intercostal arteria (Fig. 1), one bleeding from the arteria subclavia, and one bleeding from the coronary artery. Seven patients had a traumatic lesion of the thoracic aorta (Fig. 2a, b). Only three of these patients got a CT angiography. Only in one patient did we need the scan to ensure the lesion; in two cases, we repeated the scan in the arterial phase to measure the size of the aortic implant for interventional treatment (Fig. 3a, b). 3.3. Abdominal trauma We evaluated 201 patients with abdominal trauma with an average ISS of 37.4 (range, 9–75). One hundred eighty-three patients had an ISS over 15 (average, 39.5; range, 16–75). AIS score 3=97, 4=54, 5=32, and 6=0. 3.4. Injury categories We detected an injury at the liver in 39 patients (Fig. 4), at the kidney in 24 patients, at the spleen in 75 patients (Fig. 4), at the vascular system in 19 patients, at the intestine in 12 patients, at the mesenterium in 3 patients, and at the urinary tract in 10 patients. In 19 patients, we evaluated a localized ongoing bleeding of the abdominal vessels: in 10 cases, the common, external, and internal iliac arteries (Fig. 5 a–c); in 4 patients, the renal artery; in 1 case, the splenic artery; in 1 case, the celiac trunk; in 1 patient, the abdominal aorta; and in 2 patients, the superior gluteal artery. We added in three cases a CT angiography because the general situation of the patient got worse and we observed a decrease of the hemoglobin. In the initial CT, we did not see an active bleeding, and also in the follow-up CT examination, no active arterial bleeding was seen. All patients with active bleeding went immediately after the venous scan in the operation suite or to the angiography for embolization. Seven hundred twenty-nine patients (35%) went directly after the CT scan to the surgery section. All patients were observed until discharge by physicians of the intensive care and emergency unit. We look in all patients how many
Fig. 2. The axial (a) and the parasagital (b) reconstruction images showed in the venous phase a traumatic pseudoaneurysm of the aorta (arrows). This patient was brought directly in the angiography unit and was supplied an aortic stent.
and which additional imaging procedures were available in all patients. In addition, patient charts were evaluated retrospectively. 4. Discussion
Fig. 1. A 43-year-old man after a frontal car accident. The image shows an active bleeding of one of the intercostal arteries. The pleural effusion contains hyperdense area, which suggests hemothorax (arrow).
Multidetector CT is a valuable tool in the trauma setting in a variety of applications, including the examination of blunt thoracic, abdominal, and pelvic injuries, and provides rapid imaging results with a high degree of specificity and accuracy [9]. A comparison of radiation exposure from conventional radiography and from whole-body MDCT with organ-specific CT was published by Wedegartner et al. [3]. So MDCT might have saved 1 life in 1297 patients as it is supposed to be the reference standard in diagnosis of the traumatized thorax and abdomen, especially in those blunt abdominal injuries with minimal or even without intraperitoneal fluid, which are at high risk to be missed by conventional diagnostic tests [10]. Comparison of different protocols for whole-body CT shows that those for single-pass acquisition result in lower radiation exposure than do segmented, partially overlapping protocols [11]. Our protocol potentially reduces cumulative radiation dosage in multiple-trauma patients, who are often very young. A single CT data
Please cite this article as: Eichler K, et al, Multidetector computed tomography (MDCT): simple CT protocol for trauma patient, Clin Imaging (2014), http://dx.doi.org/10.1016/j.clinimag.2014.09.011
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Fig. 4. A 55-year-old man after a high-speed trauma. The contrast-enhanced image shows 85 s after beginning of contrast medium injection with a flow rate of 2 ml/s an active splenic hemorrhage and a laceration in liver segment 6 (arrows).
Fig. 3. (a) The first scan shows a circular hematoma around the thoracic aorta, so that the suspicion on traumatic aorta impairment existed (arrow). (b) The additional CT angiography confirmed the suspicion of a thoracic aortic pseudoaneurysm in the parasagittal reconstruction (arrow).
acquisition following intravenous contrast medium also means no time is needed for additional acquisitions. This saves important time in the first and “golden” hour of patient management [12]. At night, you have often a technologist who is not so familiar with CT, and therefore, it is very important that you have a protocol which is safe and simple such as a protocol with a fixed time contrast medium injection. The CT technologist is often the deciding factor in whether accurate imaging is obtained on the trauma patient. The role of the CT technologist is to scan the patient correctly the first time. It is often necessary for them to be able to perform rapid scans when evaluating a trauma patient. Arm rising in trauma CT of thoracoabdominal region will give higher image quality and lower radiation dose [13]. The time savings of not repositioning the arms after the examination of the head and cervical spine are so small that there must be a clinical reason—such as a traumatic injury to the upper chest or shoulder girdle—for the arms not to be brought towards the head [14]. Positioning of the arms above the head is in our opinion acceptable, and in our 15-year experience, we never have seen an iatrogenic lesion of the shoulder or brachial plexus.
Significant findings seen in CT of chest trauma can include pneumothorax, hemothorax, injuries to the aorta, hemorrhage of the mediastinum, and airway or diaphragm injuries. Direct impact to the chest can lead to fractures of the ribs and sternum, sternoclavicular joint dislocation, or vascular injuries [6]. Blunt trauma is the major cause of injury to the abdomen and pelvis in trauma patients. There are many different attenuation values that will be seen in abdominal MDCT. It is important to recognize which values represent normal anatomy and which are indicative of pathology. Common injuries of solid organs include contusions, lacerations, hematomas, and active extravasation. The presence of free intraperitoneal and retroperitoneal fluid is one of the most important and sensitive CT features of mesenteric and bowel injuries [15]. In a patient with blunt abdominal trauma and without intraperitoneal fluid, a surgically important bowel and/or mesenteric injury is practically excluded [16]. MDCT allows lesions in these areas to be correctly identified and proper treatment to be planned. For indications other than trauma, CT angiography has recently been shown to be accurate in the diagnosis of ongoing arterial hemorrhage in the abdomen, further raising the question of whether this application may also be useful for trauma patients [17,18]. Ongoing hemorrhage may be identified as active extravasation of intravenous contrast-enhanced blood. This appears as a focal hyperattenuating area in a region of injury with attenuation considerably higher than the adjacent organ parenchyma or soft tissue and often similar in attenuation to the aorta or large vessels located in the vicinity. The reported frequency of this finding in trauma patients varies between 13% [19] and 0.2% [20]. The CT findings have been demonstrated to be useful in predicting the need for intervention including angiography and operative repair [21]. One study has been published with regard to optimizing liver and splanchnic vessel opacification [6]; this shows that injection protocols with more than just one injection phase are advantageous compared to protocols that use a single injection phase. Bolus tracking is recommended, but not in patients with multiple trauma because of the circulatory instability present in most cases [22]. A fixed time delay using an amount of 150 ml seems to be the method of choice [7]. This already large amount of contrast media could limit its further use for angiographic interventions; our experience with 2086 patients shows in the last 5 years that the use of a 16-detector CT could decrease the amount of contrast media needed.
Please cite this article as: Eichler K, et al, Multidetector computed tomography (MDCT): simple CT protocol for trauma patient, Clin Imaging (2014), http://dx.doi.org/10.1016/j.clinimag.2014.09.011
K. Eichler et al. / Clinical Imaging xxx (2014) xxx–xxx
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Fig. 5. (a) A 58-year-old man after a car accident. The contrast-enhanced image shows 85 s after beginning of injection with a flow rate of 2 ml/s an active bleeding of the iliac arteries on the left sight (arrow). The bleeding out of the internal iliac artery on the left sight was confirmed in the angiography (b) and was embolized (c) in the next step (arrows).
5. Conclusion The results of our study show that all injuries in polytraumized patients can be detected at one very simple, stable, and effective venous scan. There were no diagnoses missed in any patients with vascular injury; no additional imaging in a later phase was deemed necessary in any of our patients. Thus, this protocol offers the potential to reduce cumulative radiation dosage by avoiding additional sequences. Followup CT of our patients using dedicated protocols has not shown a missed hematoma or organ laceration; however, very small lesions might have been missed but are probably not of any clinical relevance. The limitations of this study are the lack of comparison with other protocols, the retrospective nature of this study, and that the results are only those of a 16-detector CT. In the future, you have to compare the radiation dose in 128-row and 64-row whole-body CT.
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[4] Clarke JR, Trooskin SZ, Doshi PJ, Greenwald L, Mode CJ. Time to laparotomy for intraabdominal bleeding from trauma does affect survival for delays up to 90 minutes. J Trauma 2002;52(3):420–5. [5] Tien HC, Spencer F, Tremblay LN, Rizoli SB, Brenneman FD. Preventable deaths from hemorrhage at a level I Canadian trauma center. J Trauma 2007;62(1):142–6. [6] Awai K, Imuta M, Utsunomiya D, Nakaura T, Shamima S, Kawanaka K, et al. Contrast enhancement for whole-body screening using multidetector row helical CT: comparison between uniphasic and biphasic injection protocols. Radiat Med 2004; 22(5):303–9. [7] Linsenmaier U, Krotz M, Hauser H, Rock C, Rieger J, Bohndorf K, et al. Whole-body computed tomography in polytrauma: techniques and management. Eur Radiol 2002;12(7):1728–40. [8] Menzel HG, Schibilla H, Teunen D. European guidelines on quality criteria for computed tomography. Luxembourg: European Comission; 2000. [9] Weishaupt D, Grozaj AM, Willmann JK, Roos JE, Hilfiker PR, Marincek B. Traumatic injuries: imaging of abdominal and pelvic injuries. Eur Radiol 2002; 12(6):1295–311. [10] Ochsner MG, Knudson MM, Pachter HL, Hoyt DB, Cogbill TH, McAuley CE, et al. Significance of minimal or no intraperitoneal fluid visible on CT scan associated with blunt liver and splenic injuries: a multicenter analysis. J Trauma 2000;49(3): 505–10. [11] Ptak T, Rhea JT, Novelline RA. Radiation dose is reduced with a single-pass wholebody multi-detector row CT trauma protocol compared with a conventional segmented method: initial experience. Radiology 2003;229(3):902–5. [12] Blow O, Magliore L, Claridge JA, Butler K, Young JS. The golden hour and the silver day: detection and correction of occult hypoperfusion within 24 hours improves outcome from major trauma. J Trauma 1999;47(5):964–9. [13] Brink M, de Lange F, Oostveen LJ, Dekker HM, Kool DR, Deunk J, et al. Arm raising at exposure-controlled multidetector trauma CT of thoracoabdominal region: higher image quality, lower radiation dose. Radiology 2008;249(2):661–70. [14] Benneker LM, Bonel HM, Zumstein MA, Exadaktylos AK. A novel multiple-trauma CT-scanning protocol using patient repositioning may increase risks of iatrogenic injuries. Emerg Radiol 2007;13(6):349–51 [author reply 353].
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[15] Sharma OP, Oswanski MF, Singer D, Kenney B. The role of computed tomography in diagnosis of blunt intestinal and mesenteric trauma (BIMT). J Emerg Med 2004; 27(1):55–67. [16] Atri M, Hanson JM, Grinblat L, Brofman N, Chughtai T, Tomlinson G. Surgically important bowel and/or mesenteric injury in blunt trauma: accuracy of multidetector CT for evaluation. Radiology 2008;249(2):524–33. [17] Hyare H, Desigan S, Nicholl H, Guiney MJ, Brookes JA, Lees WR. Multi-section CT angiography compared with digital subtraction angiography in diagnosing major arterial hemorrhage in inflammatory pancreatic disease. Eur J Radiol 2006;59(2):295–300. [18] Yaniv G, Portnoy O, Simon D, Bader S, Konen E, Guranda L. Revised protocol for whole-body CT for multi-trauma patients applying triphasic injection followed by a single-pass scan on a 64-MDCT. Clin Radiol 2013;68(7):668–75.
[19] Willmann JK, Roos JE, Platz A, Pfammatter T, Hilfiker PR, Marincek B, et al. Multidetector CT: detection of active hemorrhage in patients with blunt abdominal trauma. AJR Am J Roentgenol 2002;179(2):437–44. [20] Taylor GA, Kaufman RA, Sivit CJ. Active hemorrhage in children after thoracoabdominal trauma: clinical and CT features. AJR Am J Roentgenol 1994; 162(2):401–4. [21] Fang JF, Wong YC, Lin BC, Hsu YP, Chen MF. The CT risk factors for the need of operative treatment in initially hemodynamically stable patients after blunt hepatic trauma. J Trauma 2006;61(3):547–53 [discussion 553–544]. [22] Rademacher G, Stengel D, Siegmann S, Petersein J, Mutze S. Optimization of contrast agent volume for helical CT in the diagnostic assessment of patients with severe and multiple injuries. J Comput Assist Tomogr 2002;26(1):113–8.
Please cite this article as: Eichler K, et al, Multidetector computed tomography (MDCT): simple CT protocol for trauma patient, Clin Imaging (2014), http://dx.doi.org/10.1016/j.clinimag.2014.09.011
Contents lists available at ScienceDirect
Clinical Imaging journal homepage: http://www.clinicalimaging.org
Multidetector computed tomography (MDCT): simple CT protocol for trauma patient Katrin Eichler a,⁎, Ingo Marzi b, Hendrik Wyen b, Stephan Zangos a, Martin G. Mack c, Thomas J. Vogl a a b c
Department of Diagnostic and Interventional Radiology University of Frankfurt, Germany Department of Trauma, Hand and Reconstructive Surgery University of Frankfurt, Germany Radiology Munich, Munich, Germany
a r t i c l e
i n f o
Article history: Received 13 March 2014 Received in revised form 9 September 2014 Accepted 12 September 2014 Available online xxxx Keywords: MDCT Polytrauma Fixed venous protocol Image quality
a b s t r a c t The purpose of this retrospective monocenter study was to evaluate a monophasic multidetector computed tomography (MDCT) protocol with a fixed delay for patients with polytrauma. A total of 2086 patients were evaluated retrospectively. For the intravenous contrast media, we used a fixed protocol with an injection for an adult patient of 120 mL at a rate of 2 mL/s. In the venous phase, we detected injuries of parenchyma and localized ongoing bleedings in regard to the clinical follow-up, with regard to the easy feasibility and the quickness with only one scan. Monophasic venous injection protocol can detect all injuries in the wholebody MDCT for patients with polytrauma. © 2014 Elsevier Inc. All rights reserved.
1. Introduction For initial evaluation of patients with multiple injuries, multidetectorrow computed tomography (MDCT) is considered a reliable accurate imaging modality. Radiologists constantly attempt to devise new ways to reduce the amount of time needed to adequately image trauma victims while simultaneously improving image quality [1]. The availability of MDCT in many trauma centers makes it the imaging modality of choice for the evaluation of multitrauma patients, defined as those who suffer from injuries to multiple organs, skeletal system, or vascular system obtained during a single event, in which one or more of the injuries are potentially life threatening [2]. An effective CT protocol must represent the best trade-off between high diagnostic image quality, reconstruction processing, and a short acquisition time. Both examination speed and increasing concern about the radiation dose applied necessitate one spiral acquisition instead of multiple different phases [3]. A delay in proper surgical care is a major cause for preventable deaths in trauma care, and the earliest possible identification of potential lethal injuries is mandatory for optimal trauma care [4]. Therefore, rapid depiction and therapy of injuries which can cause fatal outcome in the first 24 h after trauma are mandatory [5]. Different lesions, like hematoma and ongoing hemorrhage and parenchyma contusion or laceration of multiple organs, have to be ⁎ Corresponding author. Institute for Diagnostic and Interventional Radiology, J. W. Goethe University of Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt. Tel.: +49 69 6301 87288; fax: +49 69 6301 7288. E-mail address: [email protected] (K. Eichler).
depicted, often evaluated with a biphasic injection protocol [6]. In most cases, the administration of contrast medium for an arterial phase is difficult because bolus tracking is often inadequate following multiple trauma on account of the circulatory instability present [7]. The hypothesis of our paper is that a very simple monophasic CT monophasic protocol can depict all relevant anatomy and all pathologies.
2. Materials and methods 2.1. Patients and methods Two thousand eighty-six patients (1492 men and 594 women) with polytrauma in the last 5 years with a whole-body imaging were evaluated retrospectively. The CT scanner was located directly in the trauma resuscitation room. Before the introduction of MDCT in our trauma algorithm, conventional radiography of the pelvis and chest in combination with focused assessment with sonography for trauma was the diagnostic measure. After the scans have been completed, the algorithm continued with the necessary emergency interventions. In the meantime, the acquired data of the CT scans were processed and evaluated by a staff radiologist. The findings on the CT scan and the patient's condition determined the further procedure. So, the patient could be transferred to the operating room, to an intensive care unit, home, or to a regular surgical ward. The study was performed according to the regulations of the local ethics committee for retrospective studies and was approved by the institutional review board.
http://dx.doi.org/10.1016/j.clinimag.2014.09.011 0899-7071/© 2014 Elsevier Inc. All rights reserved.
Please cite this article as: Eichler K, et al, Multidetector computed tomography (MDCT): simple CT protocol for trauma patient, Clin Imaging (2014), http://dx.doi.org/10.1016/j.clinimag.2014.09.011
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2.2. Scanner All examinations were performed on a 16-slice MDCT system (Sensation 16; Siemens, Forchheim, Germany) with a collimation of 16×1.5 mm and a reconstruction slice thickness of both 2 and 5 mm. For normal-sized patients, a voltage of 120 kV was used. To optimize the current (mA) relative to body attenuation, the protocol used the Real-time Anatomic Exposure Control (CARE) dose 4D automatic exposure control (Siemens, Forchheim, Germany). The reference dose can only be set to one reference value for one acquisition. There are existing guidelines for the use of CT in pediatric patients from the European Union and the Food and Drug Administration [8]. With help of dose-saving mechanisms, modern CT scanners adapt the tube current to the examined volume and density of the body to reduce the effective dose. In addition, special pediatric scan protocols adapt the scan parameters to the smaller body diameters. The dose of the contrast medium (Iomeprol; Imeron 400, 400 mg/ml iodine; Altana, Konstanz, Germany) was calculated according to the patient's body weight (ml/kg body weight) and then injected intravenously in the antecubital vein at a flow rate of (ml/s) using a dual-head power injector (Injectron CT; Medtron, Saarbrücken, Germany) (Table 1). If the patient name is not known, a consecutively numbered and “no-name” emergency registration ID is used for the picture archive system and radiology information system. 2.2.1. Scanning protocol: head and cervical spine CT Head and cervical spine/neck scans were planned on a first scout and scanned without administration of intravenous contrast medium. The technologist has to search for items that could result in unwanted artifacts in the imaging study. These could range from necklaces and earrings to braids or other items on the patient's body. These should be removed before the examination. We first do a cranial spiral CT scan including the cervical vertebrae scan without intravenous contrast medium. The initial images should be analyzed at the CT console parallel to the positioning of the arms along the body. Findings are directly communicated to the neurosurgeons, the head of the trauma team, and the anesthesiologist. We use 120 kV, effective mA level of 300, rotation time of 1 s, pitch of 1, and a collimation of 16*0.75 mm. Thin slices of 1.0 mm reconstructed at 0.5-mm recon increment was obtained for bone window using the H70 very sharp kernel. Thicker slices of 5.0 mm should be reconstructed at 5-mm recon increment using the soft tissue kernel the H40 kernel medium and slices of 3.0mm should be reconstructed at 3-mm intervals using the H70 kernel. All images should are free of motion and include anatomy
Table 1 Amount of contrast medium in dependence of the weight on the patient Weight (kg)
Volume (ml)
Flow (ml/s)
Delay (s)
Jod, (gr.) absolut
5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 N100
14 19 28 37 46 56 65 74 83 93 102 111 120 120 120 120 120 120 120 120 120
0.23 0.31 0.46 0.62 0.77 0.93 1.08 1.23 1.39 1.54 1.70 1.85 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00
80 80 80 80 85 85 85 85 85 85 85 85 85 85 85 85 85 85 85 85 85
5.55 7.4 11.1 14.8 18.5 22.2 25.9 29.6 33.3 37 40.7 44.4 48.1 48.1 48.1 48.1 48.1 48.1 48.1 48.1 48.1
from the top of the skull through the end of the cervical vertebra. Sagittal and coronal multiplanar reconstructions (MPRs) were obtained using the bone window using distance of 2 mm and thickness of 2 mm. For the coronal MPR, we used the curved reconstruction. 2.2.2. Chest abdomen, pelvis, and spinal column CT acquisition was started at the middle of the seventh cervical spinal column and ended at the proximal femur. The arms were positioned over the head. Infusion lines, monitoring cables, and resuscitation tubes exit at the foot end. Prior the injection of iodinated contrast material, every iv access should be checked with an injection of at least 10 ml of saline. Any iv access that does not seem adequate for injection should not be used. Poor iv access can be a challenging pitfall in MDCT examinations because obtaining iv access in trauma patients can be difficult due to positioning. Trauma patients may have decreased iv access due to fractures, active bleeding, or poor vein patency. The contrast medium was administered via an 18-G peripheral access by means of an automated pump injector using a fixed injection protocol. For all injections in this study, the same injection device was used (Injectron CT; Medtron, Saarbrücken, Germany). For the injection of contrast media, we used a fixed protocol with an injection for an adult patient of 120 ml at a rate of 2 ml/s of a contrast medium containing 400 mg/ml iodine (Iomeprol; Imeron 400, 400 mg/ml iodine; Altana, Konstanz, Germany) followed by 60 ml NaCL at a rate of 2 ml/s. The body weights in adult patients and the renal clearances of the patients and their history of possible reactions to contrast material were not known at the time of the examination. Eighty-five seconds after the beginning of the injection, the CT acquisition was started. Delayed imaging in a low-dose technique to detect pelvicalyceal or disruption of the ureter was only performed in patients with damage in the kidneys in the venous phase. Images are reconstructed using soft tissue, bone, and lung windows. In the soft tissue window, images are reconstructed using 5-mm slice thickness with 5-mm intervals and a B30 medium smooth kernel. In the lung window, images are generated using a 5-mm slice thickness reconstructed at a 5-mm recon increment using the B60 sharp kernel. The bone window reconstructions are generated using a 2-mm slice thickness at 1-mm recon increment using the B70 very sharp kernel. Sagittal and coronal MPRs are obtained using the bone and soft tissue windows. For the sagittal and curved coronal reconstructions, we use a distance of 2 mm and a thickness of 3 mm. A radiologist with at least 3-year experience immediately makes the results. The results are checked and also released on the same day or subsequent day by a senior physician. 3. Results Two thousand eighty-six consecutive patients with a median age of 39.7 years (range, 1–96 years) including 1492 men and 594 women were evaluated retrospectively in a 5-year interval. Nine hundred sixty-eight patients had an Injury Severity Score (ISS) over 15. In 1934 (92.7%), it was a blunt injury; in 152 (7.3%), it was a penetrating injury. The causes divide themselves as follows: accident: 1854; suicide, 96; violence, 89; jump fall N 3 m, 283; jump fall b 3 m, 417; traffic accident: 996; pedestrian, 206; car, 406; motor bike, 201; bicycle, 183. 3.1. Thoracictrauma We evaluated 611 patients with thorax trauma with an average ISS of 32.5 (range, 4–75). Five hundred forty-four patients had an ISS over 15 (average, 35.5; range, 16–75). Abbreviated Injury Scale (AIS) 3= 198, 4=279, 5=64, and 6=2.
Please cite this article as: Eichler K, et al, Multidetector computed tomography (MDCT): simple CT protocol for trauma patient, Clin Imaging (2014), http://dx.doi.org/10.1016/j.clinimag.2014.09.011
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3.2. Injury categories We detected in 204 patients a rib fracture, in 295 patients a lung contusion, in 251 a pneumothorax, in 84 patients a hemothorax, in 14 patients a vascular injury, and in 15 patients another category. We detected two active bleedings from an intercostal arteria (Fig. 1), one bleeding from the arteria subclavia, and one bleeding from the coronary artery. Seven patients had a traumatic lesion of the thoracic aorta (Fig. 2a, b). Only three of these patients got a CT angiography. Only in one patient did we need the scan to ensure the lesion; in two cases, we repeated the scan in the arterial phase to measure the size of the aortic implant for interventional treatment (Fig. 3a, b). 3.3. Abdominal trauma We evaluated 201 patients with abdominal trauma with an average ISS of 37.4 (range, 9–75). One hundred eighty-three patients had an ISS over 15 (average, 39.5; range, 16–75). AIS score 3=97, 4=54, 5=32, and 6=0. 3.4. Injury categories We detected an injury at the liver in 39 patients (Fig. 4), at the kidney in 24 patients, at the spleen in 75 patients (Fig. 4), at the vascular system in 19 patients, at the intestine in 12 patients, at the mesenterium in 3 patients, and at the urinary tract in 10 patients. In 19 patients, we evaluated a localized ongoing bleeding of the abdominal vessels: in 10 cases, the common, external, and internal iliac arteries (Fig. 5 a–c); in 4 patients, the renal artery; in 1 case, the splenic artery; in 1 case, the celiac trunk; in 1 patient, the abdominal aorta; and in 2 patients, the superior gluteal artery. We added in three cases a CT angiography because the general situation of the patient got worse and we observed a decrease of the hemoglobin. In the initial CT, we did not see an active bleeding, and also in the follow-up CT examination, no active arterial bleeding was seen. All patients with active bleeding went immediately after the venous scan in the operation suite or to the angiography for embolization. Seven hundred twenty-nine patients (35%) went directly after the CT scan to the surgery section. All patients were observed until discharge by physicians of the intensive care and emergency unit. We look in all patients how many
Fig. 2. The axial (a) and the parasagital (b) reconstruction images showed in the venous phase a traumatic pseudoaneurysm of the aorta (arrows). This patient was brought directly in the angiography unit and was supplied an aortic stent.
and which additional imaging procedures were available in all patients. In addition, patient charts were evaluated retrospectively. 4. Discussion
Fig. 1. A 43-year-old man after a frontal car accident. The image shows an active bleeding of one of the intercostal arteries. The pleural effusion contains hyperdense area, which suggests hemothorax (arrow).
Multidetector CT is a valuable tool in the trauma setting in a variety of applications, including the examination of blunt thoracic, abdominal, and pelvic injuries, and provides rapid imaging results with a high degree of specificity and accuracy [9]. A comparison of radiation exposure from conventional radiography and from whole-body MDCT with organ-specific CT was published by Wedegartner et al. [3]. So MDCT might have saved 1 life in 1297 patients as it is supposed to be the reference standard in diagnosis of the traumatized thorax and abdomen, especially in those blunt abdominal injuries with minimal or even without intraperitoneal fluid, which are at high risk to be missed by conventional diagnostic tests [10]. Comparison of different protocols for whole-body CT shows that those for single-pass acquisition result in lower radiation exposure than do segmented, partially overlapping protocols [11]. Our protocol potentially reduces cumulative radiation dosage in multiple-trauma patients, who are often very young. A single CT data
Please cite this article as: Eichler K, et al, Multidetector computed tomography (MDCT): simple CT protocol for trauma patient, Clin Imaging (2014), http://dx.doi.org/10.1016/j.clinimag.2014.09.011
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Fig. 4. A 55-year-old man after a high-speed trauma. The contrast-enhanced image shows 85 s after beginning of contrast medium injection with a flow rate of 2 ml/s an active splenic hemorrhage and a laceration in liver segment 6 (arrows).
Fig. 3. (a) The first scan shows a circular hematoma around the thoracic aorta, so that the suspicion on traumatic aorta impairment existed (arrow). (b) The additional CT angiography confirmed the suspicion of a thoracic aortic pseudoaneurysm in the parasagittal reconstruction (arrow).
acquisition following intravenous contrast medium also means no time is needed for additional acquisitions. This saves important time in the first and “golden” hour of patient management [12]. At night, you have often a technologist who is not so familiar with CT, and therefore, it is very important that you have a protocol which is safe and simple such as a protocol with a fixed time contrast medium injection. The CT technologist is often the deciding factor in whether accurate imaging is obtained on the trauma patient. The role of the CT technologist is to scan the patient correctly the first time. It is often necessary for them to be able to perform rapid scans when evaluating a trauma patient. Arm rising in trauma CT of thoracoabdominal region will give higher image quality and lower radiation dose [13]. The time savings of not repositioning the arms after the examination of the head and cervical spine are so small that there must be a clinical reason—such as a traumatic injury to the upper chest or shoulder girdle—for the arms not to be brought towards the head [14]. Positioning of the arms above the head is in our opinion acceptable, and in our 15-year experience, we never have seen an iatrogenic lesion of the shoulder or brachial plexus.
Significant findings seen in CT of chest trauma can include pneumothorax, hemothorax, injuries to the aorta, hemorrhage of the mediastinum, and airway or diaphragm injuries. Direct impact to the chest can lead to fractures of the ribs and sternum, sternoclavicular joint dislocation, or vascular injuries [6]. Blunt trauma is the major cause of injury to the abdomen and pelvis in trauma patients. There are many different attenuation values that will be seen in abdominal MDCT. It is important to recognize which values represent normal anatomy and which are indicative of pathology. Common injuries of solid organs include contusions, lacerations, hematomas, and active extravasation. The presence of free intraperitoneal and retroperitoneal fluid is one of the most important and sensitive CT features of mesenteric and bowel injuries [15]. In a patient with blunt abdominal trauma and without intraperitoneal fluid, a surgically important bowel and/or mesenteric injury is practically excluded [16]. MDCT allows lesions in these areas to be correctly identified and proper treatment to be planned. For indications other than trauma, CT angiography has recently been shown to be accurate in the diagnosis of ongoing arterial hemorrhage in the abdomen, further raising the question of whether this application may also be useful for trauma patients [17,18]. Ongoing hemorrhage may be identified as active extravasation of intravenous contrast-enhanced blood. This appears as a focal hyperattenuating area in a region of injury with attenuation considerably higher than the adjacent organ parenchyma or soft tissue and often similar in attenuation to the aorta or large vessels located in the vicinity. The reported frequency of this finding in trauma patients varies between 13% [19] and 0.2% [20]. The CT findings have been demonstrated to be useful in predicting the need for intervention including angiography and operative repair [21]. One study has been published with regard to optimizing liver and splanchnic vessel opacification [6]; this shows that injection protocols with more than just one injection phase are advantageous compared to protocols that use a single injection phase. Bolus tracking is recommended, but not in patients with multiple trauma because of the circulatory instability present in most cases [22]. A fixed time delay using an amount of 150 ml seems to be the method of choice [7]. This already large amount of contrast media could limit its further use for angiographic interventions; our experience with 2086 patients shows in the last 5 years that the use of a 16-detector CT could decrease the amount of contrast media needed.
Please cite this article as: Eichler K, et al, Multidetector computed tomography (MDCT): simple CT protocol for trauma patient, Clin Imaging (2014), http://dx.doi.org/10.1016/j.clinimag.2014.09.011
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Fig. 5. (a) A 58-year-old man after a car accident. The contrast-enhanced image shows 85 s after beginning of injection with a flow rate of 2 ml/s an active bleeding of the iliac arteries on the left sight (arrow). The bleeding out of the internal iliac artery on the left sight was confirmed in the angiography (b) and was embolized (c) in the next step (arrows).
5. Conclusion The results of our study show that all injuries in polytraumized patients can be detected at one very simple, stable, and effective venous scan. There were no diagnoses missed in any patients with vascular injury; no additional imaging in a later phase was deemed necessary in any of our patients. Thus, this protocol offers the potential to reduce cumulative radiation dosage by avoiding additional sequences. Followup CT of our patients using dedicated protocols has not shown a missed hematoma or organ laceration; however, very small lesions might have been missed but are probably not of any clinical relevance. The limitations of this study are the lack of comparison with other protocols, the retrospective nature of this study, and that the results are only those of a 16-detector CT. In the future, you have to compare the radiation dose in 128-row and 64-row whole-body CT.
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