Michael J. R. Edwards

Arm Raising at Exposure-controlled Multidetector Trauma CT of Thoracoabdominal Region: Higher Image Quality, Lower Radiation Dose

PURPOSEnTo evaluate the effect of arm position on image quality and effective radiation dose in an automatic exposure-controlled (AEC) multidetector thoracoabdominal computed tomography (CT) protocol in trauma patients.nnnMATERIALS AND METHODSnThis retrospective study of the data of 177 trauma patients (117 male; median age, 39 years) was approved by the institutional ethics board, with informed patient consent waived. Patients underwent scanning by using an AEC 16-detector thoracoabdominal CT protocol in which both arms were raised above the shoulder region (standard-position group, 132 patients), one arm was raised and the other was down (one-arm group, 27 patients), or both arms were down (two-arm group, 18 patients). Objective and subjective image quality was assessed. Individual effective radiation dose was calculated from the effective tube current-time product per exposed section. For this purpose, section location-dependent conversion factors were derived by using a CT dosimetry calculator. The effect of arm position on effective dose was quantified by using linear regression analysis with correction for patient volume and attenuation.nnnRESULTSnCompared with the image quality in the standard-position group, the image quality in the one- and two-arm groups was decreased but within acceptable diagnostic limits. The median corrected effective dose in the standard-position group was 18.6 mSv; the dose in the one-arm group was 18% (95% confidence interval: 11%, 25%) higher than this, and that in the two-arm group was 45% (95% confidence interval: 34%, 57%) higher.nnnCONCLUSIONnOmitting arm raising results in lower but acceptable image quality and a substantially higher effective radiation dose. Hence, effort should be made to position the arms above the shoulder when scanning trauma patients. Clinical trial registration no. NCT00228111.

Added Value of Routine Chest MDCT After Blunt Trauma: Evaluation of Additional Findings and Impact on Patient Management

OBJECTIVEnThe objective of our study was to evaluate the added value of a low-threshold routine thoracic MDCT algorithm compared with a selective MDCT algorithm in adult blunt trauma patients.nnnSUBJECTS AND METHODSnA prospective cohort study was conducted in 464 consecutive blunt trauma patients who met criteria indicative of severe blunt trauma (66% male; age range, 16-93 years; median injury severity score, 13). After clinical evaluation and conventional radiography of the chest and thoracic spine, all patients underwent routine thoracic MDCT with an IV contrast agent (routine MDCT algorithm). Within this routine MDCT group, a subgroup was prospectively defined with abnormal or inconclusive clinical or conventional radiography evaluation (selective MDCT group). Two investigators determined the type, extent, and clinical impact of additional injuries found on MDCT as compared to conventional radiography for both MDCT groups.nnnRESULTSnOf all 464 patients within the routine MDCT group, 164 patients underwent selective MDCT, which resulted in detection of additional diagnoses compared with conventional radiography in 97 (59%) patients. The routine MDCT algorithm detected additional diagnoses compared with conventional radiography in 201 of 464 patients (43%). Compared with the selective MDCT algorithm, this was an absolute increase of 104 of 464 (22%) extra patients, resulting in a change in patient management in 34 (7%; 95% CI, 5-9.7%), mostly because of additional findings of pulmonary and mediastinal injury.nnnCONCLUSIONnRoutine MDCT has relatively lower, though still substantial, added diagnostic value compared with selective MDCT of the chest.

Routine Versus Selective Computed Tomography of the Abdomen, Pelvis, and Lumbar Spine in Blunt Trauma : A Prospective Evaluation

BACKGROUNDnDiscussion still remains whether computed tomography (CT) of the abdomen, pelvis, and lumbar spine should be performed routinely after blunt trauma with high energy impact or only in restricted situations. The purpose of this study was to evaluate the additional value of a routine CT algorithm as compared with a more restricted, selective CT algorithm.nnnMATERIALSnThis prospective study consisted of 465 patients that met the inclusion criteria of our high-energy trauma protocol. All patients underwent physical examination, abdominal ultrasound (AUS), and conventional radiography (CR) of the pelvis and lumbar spine and subsequently routine CT of the abdomen, pelvis, and lumbar spine. Before CT, a subgroup of patients with abnormal physical examination or CR or AUS was prospectively defined as the selective CT group. Type and extent of injuries and impact on treatment were recorded for both the routine CT group and the selective CT subgroup.nnnRESULTSnOf all patients, 42 received selective CT of the abdomen, 71 of the pelvis, and 48 of the lumbar spine. Compared with the algorithm with selective CT, routine CT revealed additional traumatic injuries in 15% of the patients in the abdomen, in 2.4% in the pelvis and in 8.2% in the lumbar spine. This resulted in an overall change of treatment in 6.4% (95% confidence interval, 3.7-9.0) of the patients who would not have received CT in a selective CT algorithm.nnnCONCLUSIONSnCompared with an algorithm with selective CT, an algorithm with routine CT finds substantially more clinically relevant diagnoses, even in patients with unsuspicious clinical examination, normal CR, and normal AUS.

The Clinical Outcome of Occult Pulmonary Contusion on Multidetector-Row Computed Tomography in Blunt Trauma Patients

BACKGROUNDnMultidetector-row computed tomography (MDCT) is a more sensitive modality as compared with conventional radiography (CR) in detecting pulmonary injuries. MDCT often detects pulmonary contusion that is not visualized by CR, defined as occult pulmonary contusion (OPC). The aim of this study was to investigate whether OPC on MDCT has implications for the outcome in blunt trauma patients.nnnMETHODSnWe used prospectively collected data from 1,040 adult high-energy blunt trauma patients who were primarily presented at our emergency department and who underwent CR and MDCT of the chest. All patients with pulmonary contusion were identified and divided into two groups: The CR/computed tomography (CT) group consisted of patients with pulmonary contusion visible on both CR and MDCT. The CT-only group consisted of patients with OPC, visible exclusively on MDCT. The control group consisted of blunt trauma patients without pulmonary contusion. These groups were compared with respect to difference in mortality and other outcome measures. In addition, a multivariate analysis was performed.nnnRESULTSnTwo hundred fifty-five patients suffered pulmonary contusion: The CT-only group consisted of 157 and the CR/CT group of 98 patients. The CT-only group did not differ from the control group with respect to mortality rate and other outcome measures. However, compared with the CR/CT group, mortality rate was significantly lower (8% versus 16%, p = 0.039) and most other outcome measures were significantly better in the CT-only group.nnnCONCLUSIONnOPC on MDCT is not associated with a worse outcome as compared with patients without pulmonary contusion. OPC has a better outcome as compared with pulmonary contusion visible on both CR and MDCT.

Routine versus selective multidetector-row computed tomography (MDCT) in blunt trauma patients: level of agreement on the influence of additional findings on management.

INTRODUCTIONnThis study was performed to determine the agreement between and within surgeons concerning the influence on treatment plan of routine versus selective multidetector-row computed tomography (MDCT) findings in blunt trauma patients.nnnPATIENTSnFor this study, 50 patients were randomly selected from a customized database that was originally used to compare a diagnostic algorithm with a selective use of MDCT with an algorithm with routine MDCT of the spine, chest, and abdomen within the same population. In all 50 patients, routine MDCT found additional diagnoses as compared with the selective MDCT algorithm. Of all patients, paper cases were created with detailed information on clinical parameters, findings by physical examination, and radiologic findings. The cases were independently presented to three different trauma surgeons. First, the surgeons were asked for their treatment plan based upon diagnoses found by physical examination, conventional radiography, and selective MDCT alone. Subsequently they were asked for their treatment plan with knowledge of the injuries additionally found by routine MDCT. This procedure was repeated after 3 months. The agreement between and within surgeons was determined for the change of patient management because of additional findings by routine MDCT.nnnRESULTSnThe agreement on the influence of routine MDCT findings on patient management between surgeons was moderate ([kappa] = 0.46) in the first procedure and substantial in the second ([kappa] = 0.67). The agreement within surgeons ranged from moderate ([kappa] = 0.60) to excellent ([kappa] = 0.87).nnnCONCLUSIONnAll surgeons agreed that the traumatic injuries additionally found by routine MDCT, frequently resulted in a change of treatment plan. There was a moderate-to-excellent agreement between and within surgeons that these additional findings resulted in a change of treatment plan.

Criteria for the selective use of chest computed tomography in blunt trauma patients

PurposeThe purpose of this study was to derive parameters that predict which high-energy blunt trauma patients should undergo computed tomography (CT) for detection of chest injury.MethodsThis observational study prospectively included consecutive patients (≥16xa0years old) who underwent multidetector CT of the chest after a high-energy mechanism of blunt trauma in one trauma centre.ResultsWe included 1,047 patients (median age, 37; 70% male), of whom 508 had chest injuries identified by CT. Using logistic regression, we identified nine predictors of chest injury presence on CT (age ≥55xa0years, abnormal chest physical examination, altered sensorium, abnormal thoracic spine physical examination, abnormal chest conventional radiography (CR), abnormal thoracic spine CR, abnormal pelvic CR or abdominal ultrasound, base excess <−3xa0mmol/l and haemoglobin <6xa0mmol/l). Of 855 patients with ≥1 positive predictors, 484 had injury on CT (95% of all 508 patients with injury). Of all 192 patients with no positive predictor, 24 (13%) had chest injury, of whom 4 (2%) had injuries that were considered clinically relevant.ConclusionOmission of CT in patients without any positive predictor could reduce imaging frequency by 18%, while most clinically relevant chest injuries remain adequately detected.

Predictors of abnormal chest CT after blunt trauma: a critical appraisal of the literature.

AIMnTo identify and to evaluate predictors that determine whether chest computed tomography (CT) is likely to reveal relevant injuries in adult blunt trauma patients.nnnMETHODSnAfter a comprehensive literature search for original studies on blunt chest injury diagnosis, two independent observers included studies on the accuracy of parameters derived from history, physical examination, or diagnostic imaging that might predict injuries at (multidetector row) CT in adults and that allowed construction of 2x2 contingency tables. For each article, methodological quality was scored and relevant predictors for injuries at CT were extracted. For each predictor, sensitivity, specificity, positive and negative likelihood ratio and diagnostic odds ratio (DOR) including 95% confidence intervals were calculated.nnnRESULTSnOf 147 articles initially identified, the observers included 10 original studies in consensus. Abnormalities at physical examination (abnormal respiratory effort, need for assisted ventilation, reduced airentry, coma, chest wall tenderness) and pelvic fractures were significant predictors (DOR: 2.1-6.7). The presence of any injuries at conventional radiography of the chest (eight articles) was a more powerful significant predictor (DOR: 2.2-37). Abnormal chest ultrasonography (four articles) was the most accurate predictor for chest injury at CT (DOR: 491-infinite).nnnCONCLUSIONnThe current literature indicates that in blunt trauma patients with abnormal physical examination, abnormal conventional radiography, or abnormal ultrasonography of the chest, CT was likely to reveal relevant chest injuries. However, there was no strong evidence to suggest that CT could be omitted in patients without these criteria, or whether these findings are beneficial for patients.

An evidence based blunt trauma protocol

Objective Currently CT is rapidly implemented in the evaluation of trauma patients. In anticipation of a large international multicentre trial, this studys aim was to evaluate the clinical feasibility of a new diagnostic protocol, used for the primary radiological evaluation in adult blunt high-energy trauma patients, especially for the use of CT. Methods An evidence-based flow chart was created with criteria based on trauma mechanism, physical examination and laboratory analyses to indicate appropriateness of conventional radiography (CR), sonography and CT of head, cervical spine and trunk. To evaluate this protocol, the authors prospectively included 81 consecutive patients. Collected data included protocol adherence and number and type of performed CR and CT scans. The authors also determined the time needed to perform radiological investigations, adverse events in the CT room and clinically relevant missed injuries after 1-month clinical follow-up. Results There was 99% adherence to the protocol concerning CT. Seventy-nine patients (98%) received one or more CT scans: 72 (89%) had thoracoabdominal, 78 (96%) cervical spine and 54 (67%) had cranial CT. In 30 patients, one or more CT scans of body regions could be omitted. In 38%, CR was wrongly omitted or performed incorrectly at a variance with the protocol. No major adverse events occurred in the CT room and no clinically relevant injuries were missed. Conclusions The authors introduced a diagnostic protocol that seems feasible and safe for the evaluation of adult blunt high-energy trauma patients. Implementation of this protocol has the potential to reduce unnecessary radiological investigations, especially CT scans.

Is a pelvic fracture a predictor for thoracolumbar spine fractures after blunt trauma

BACKGROUNDnDiscussion still remains which polytraumatized patients require radiologic thoracolumbar spine (TL spine) screening. The purpose of this study is to determine whether pelvic fractures are associated with TL spine fractures after a blunt trauma. Additionally, the sensitivity of conventional TL spine radiographs and pelvic radiographs (PXRs) is evaluated.nnnMETHODSnWe prospectively studied 721 consecutive patients who had sustained a high-energy blunt trauma. The diagnostic workup in these patients included routine conventional radiographs of the pelvis and TL spine followed by a computed tomography (CT) analysis. All patients with pelvic fractures and TL spine fractures identified on conventional radiographs and CT were analyzed. A relative risk (RR) was calculated for the association between pelvic fractures and TL spine fractures. The sensitivity for conventional TL spine radiographs and PXRs in identifying fractures was calculated.nnnRESULTSnOf the 721 patients studied, 620 were included in our diagnostic high-energy trauma protocol. Of these 620 included patients, 86 (14%) suffered a pelvic fracture and 126 (20%) suffered a TL spine fracture. Thirty-three patients (5%) suffered both a pelvic fracture and a TL spine fracture. The RR for a TL spine fracture in the presence of a pelvic fracture identified on PXR is 2.14 (95% confidence interval, 1.54-2.98) and identified on CT this RR is 2.20 (95% confidence interval, 1.59-3.05). However, this association diminishes to a nonsignificant level when the transverse process and spinous process fractures are excluded. Overall sensitivity for conventional TL spine radiographs and PXRs is 22% and 69%, respectively.nnnCONCLUSIONnOur data suggest that a pelvic fracture is not a predictor for clinically relevant TL spine fractures. Furthermore, our data confirm the superior sensitivity of CT for detecting TL spine injury and pelvic fractures.

Predicting Survival after Trauma: a Comparison of TRISS and ASCOT in the Netherlands

AbstractBackground: Evaluating the performance of a trauma system may be attempted by comparing outcome in different trauma populations. Controlling for injury severity is a necessity for such evaluations. We compare two current models for doing so: the “Trauma and Injury Severity Score” (TRISS) and “A Severity Characterization Of Trauma” (ASCOT).nMaterial and Methods: This study of high-energy trauma victims took place in Leiden, the Netherlands, between 1993 and 1998. Using the Hosmer-Lemeshow (HL) test and receiver operator characteristic (ROC) analysis, the TRISS and ASCOT models were compared for calibration and discrimination.nResults: 1,024 patients, with an average Injury Severity Score (ISS) of 13.5, were eligible for inclusion. Blunt trauma was the predominant cause of injuries. Both models gave accurate, though pessimistic, results in predicting the actual number of fatalities (n = 71). The HL test indicated a sufficient fit for the ASCOT model (p = 0.28) and an insufficient fit (p = 0.02) for TRISS. The ROC curves were nearly identical (0.97). Including age as a linear variable, instead of using the current age groups, resulted in an improved discriminative power of the models.nConclusions: The ASCOT model proved superior over TRISS in its accuracy to estimate of survival chances. This difference was most evident for victims with an estimated survival chance of 60–90%. Future national trauma researchers should therefore collect ASCOT data. Improved ASCOT models could be developed, with age as a linear variable.