American Association For The Surgery Of Trauma Grading System Research Articles

A deep learning framework for automated detection and quantitative assessment of liver trauma

BackgroundBoth early detection and severity assessment of liver trauma are critical for optimal triage and management of trauma patients. Current trauma protocols utilize computed tomography (CT) assessment of injuries in a subjective and qualitative (v.s. quantitative) fashion, shortcomings which could both be addressed by automated computer-aided systems that are capable of generating real-time reproducible and quantitative information. This study outlines an end-to-end pipeline to calculate the percentage of the liver parenchyma disrupted by trauma, an important component of the American Association for the Surgery of Trauma (AAST) liver injury scale, the primary tool to assess liver trauma severity at CT.MethodsThis framework comprises deep convolutional neural networks that first generate initial masks of both liver parenchyma (including normal and affected liver) and regions affected by trauma using three dimensional contrast-enhanced CT scans. Next, during the post-processing step, human domain knowledge about the location and intensity distribution of liver trauma is integrated into the model to avoid false positive regions. After generating the liver parenchyma and trauma masks, the corresponding volumes are calculated. Liver parenchymal disruption is then computed as the volume of the liver parenchyma that is disrupted by trauma.ResultsThe proposed model was trained and validated on an internal dataset from the University of Michigan Health System (UMHS) including 77 CT scans (34 with and 43 without liver parenchymal trauma). The Dice/recall/precision coefficients of the proposed segmentation models are 96.13/96.00/96.35% and 51.21/53.20/56.76%, respectively, in segmenting liver parenchyma and liver trauma regions. In volume-based severity analysis, the proposed model yields a linear regression relation of 0.95 in estimating the percentage of liver parenchyma disrupted by trauma. The model shows an accurate performance in avoiding false positives for patients without any liver parenchymal trauma. These results indicate that the model is generalizable on patients with pre-existing liver conditions, including fatty livers and congestive hepatopathy.ConclusionThe proposed algorithms are able to accurately segment the liver and the regions affected by trauma. This pipeline demonstrates an accurate performance in estimating the percentage of liver parenchyma that is affected by trauma. Such a system can aid critical care medical personnel by providing a reproducible quantitative assessment of liver trauma as an alternative to the sometimes subjective AAST grading system that is used currently.

Revision of the AAST grading scale for acute cholecystitis with comparison to physiologic measures of severity.

Grading systems for acute cholecystitis are essential to compare outcomes, improve quality, and advance research. The American Association for the Surgery of Trauma (AAST) grading system for acute cholecystitis was only moderately discriminant when predicting multiple outcomes and underperformed the Tokyo guidelines and Parkland grade. We hypothesized that through additional expert consensus, the predictive capacity of the AAST anatomic grading system could be improved. A modified Delphi approach was used to revise the AAST grading system. Changes were made to improve distribution of patients across grades, and additional key clinical variables were introduced. The revised version was assessed using prospectively collected data from an AAST multicenter study. Patient distribution across grades was assessed, and the revised grading system was evaluated based on predictive capacity using area under receiver operating characteristic curves for conversion from laparoscopic to an open procedure, use of a surgical "bail-out" procedure, bile leak, major complications, and discharge home. A preoperative AAST grade was defined based on preoperative, clinical, and radiologic data, and the Parkland grade was also substituted for the operative component of the AAST grade. Using prospectively collected data on 861 patients with acute cholecystitis the revised version of the AAST grade has an improved distribution across all grades, both the overall grade and across each subscale. A higher AAST grade predicted each of the outcomes assessed (all p ≤ 0.01). The revised AAST grade outperformed the original AAST grade for predicting operative outcomes and discharge disposition. Despite this improvement, the AAST grade did not outperform the Parkland grade or the Emergency Surgery Score. The revised AAST grade and the preoperative AAST grade demonstrated improved discrimination; however, a purely anatomic grade based on chart review is unlikely to predict outcomes without addition of physiologic variables. Follow-up validation will be necessary. Diagnostic Test or Criteria, Level IV.

Invited Commentary: Key Concepts of CT for Penetrating Abdominopelvic Injuries.

Invited Commentary: Key Concepts of CT for Penetrating Abdominopelvic Injuries.

The American Association for the Surgery of Trauma renal injury grading scale: Implications of the 2018 revisions for injury reclassification and predicting bleeding interventions.

In 2018, the American Association for the Surgery of Trauma (AAST) published revisions to the renal injury grading system to reflect the increased reliance on computed tomography scans and non-operative management of high-grade renal trauma (HGRT). We aimed to evaluate how these revisions will change the grading of HGRT and if it outperforms the original 1989 grading in predicting bleeding control interventions. Data on HGRT were collected from 14 Level-1 trauma centers from 2014 to 2017. Patients with initial computed tomography scans were included. Two radiologists reviewed the scans to regrade the injuries according to the 1989 and 2018 AAST grading systems. Descriptive statistics were used to assess grade reclassifications. Mixed-effect multivariable logistic regression was used to measure the predictive ability of each grading system. The areas under the curves were compared. Of the 322 injuries included, 27.0% were upgraded, 3.4% were downgraded, and 69.5% remained unchanged. Of the injuries graded as III or lower using the 1989 AAST, 33.5% were upgraded to grade IV using the 2018 AAST. Of the grade V injuries, 58.8% were downgraded using the 2018 AAST. There was no statistically significant difference in the overall areas under the curves between the 2018 and 1989 AAST grading system for predicting bleeding interventions (0.72 vs. 0.68, p = 0.34). About one third of the injuries previously classified as grade III will be upgraded to grade IV using the 2018 AAST, which adds to the heterogeneity of grade IV injuries. Although the 2018 AAST grading provides more anatomic details on injury patterns and includes important radiologic findings, it did not outperform the 1989 AAST grading in predicting bleeding interventions. Prognostic and Epidemiological Study, level III.

MSCT IN NON-OPERATIVE MANAGEMENT OF HIGH GRADE BLUNT RENAL TRAUMA, A PROSPECTIVE STUDY

Aim: To highlight the validity of MSCT in predicting the efficacy of non-operative management in patients with high grade blunt renal trauma using American Association for the Surgery of Trauma (AAST) renal injury scale Patients and methods: Through a prospective study included 39 patients with high grades blunt renal traumas (grade III, IV and V), MSCT was done for all included cases and correlated to AAST grading system then we followed up non-operated cases by clinical, laboratory and US for all cases and CT in 12 cases along two weeks period. Statistical analysis was done for planed management immediately after CT and proper management done through two weeks of follow up. Results: MSCT graded the injury into grade III, IV and V according to AAST grading system presented in 48.7%, 33.3% and 17.9 % respectively. 74.4% of cases underwent conservative management, 5.1% underwent immediate surgical nephrectomy, 7.7 % underwent intervention embolization and double J fixation was done in 7.7%. Within 2 weeks of follow up conservative management was sufficient in only 64.1% as some patients developed other predisposing factors demanded further interventions and a total percentage of 17.9% of our cases underwent surgical laparotomy (6 cases nephrectomy and one case renorrhaphy), surgical percutaneous drainage of urinoma in one case and renal artery embolization raised to 10.3% of our cases. Conclusion: MSCT can determine the exact criteria for selecting patients for conservative management in hemodynamic stable patients. Non-operative management strategy in line with repeated imaging and close clinical follow up salvaged the affected kidney in most of the cases.

Pediatric Appendicitis Severity in KwaZulu‐Natal, South Africa: A Retrospective Cohort Analysis

Acute appendicitis is a common pediatric surgical emergency; however, there are few grading systems to assign disease severity. The American Association for the Surgery of Trauma (AAST) recently developed a grading system for a variety of emergency surgical conditions, including appendicitis. The severity of acute appendicitis in younger patients in KwaZulu-Natal (South Africa) is unknown. We aimed to describe the disease severity in this patient population using the AAST grading system hypothesizing that the AAST grade would correlate with morbidity, management type, and duration of stay. Single institutional review of patients <18years old with a final diagnosis of acute appendicitis during 2010-2016 in KwaZulu-Natal, South Africa, was performed. Demographics, physiologic and symptom data, procedural details, postoperative complications, and Clavien-Dindo classification were abstracted. AAST grades were generated based on intraoperative findings. Summary, univariate, and nominal logistic regression analyses were performed to compare AAST grade and outcomes. A total of 401 patients were identified with median [IQR] age of 11 [5-13], 65% male. Appendectomy was performed in all patients; 2.4% laparoscopic, 37.6% limited incision, and 60% midline laparotomy. Complications occurred in 41.6%, most commonly unplanned relaparotomy (22.4%), surgical site infection (8.9%), pneumonia (7.2%), and acute renal failure (2.9%). Complication rate and median length of stay increased with greater AAST grade (all p < 0.001). AAST grade was independently associated with increased risk of complications. Pediatric appendicitis is a morbid disease in a developing middle-income country. The AAST grading system is generalizable and accurately corresponds with management strategies as well as key clinical outcomes. Retrospective study, Level IV. Retrospective single institutional study.

Validation of the AAST EGS acute cholecystitis grade and comparison with the Tokyo guidelines

BackgroundAcute cholecystitis presents with heterogeneous severity. The Tokyo Guidelines 2013 is a validated method to assess cholecystitis severity, but the variables are multifactorial. The American Association for the Surgery of Trauma (AAST) developed an anatomically based severity grading system for surgical diseases, including cholecystitis. Because the Tokyo Guidelines represent the gold standard to estimate acute cholecystitis severity, we wished to validate the AAST emergency general surgery scoring system and compare the performance of both systems for several patient outcomes. MethodsAdults (≥18 years) with acute cholecystitis during 2013–2016 were identified. Baseline demographic characteristics, comorbidity severity as defined by Charlson Comorbidity Index score, procedure types, and AAST and Tokyo Guidelines 2013 grades were abstracted. Outcomes included duration of stay, 30-day mortality, and complications. Comparison of the Tokyo Guidelines and AAST grading system was performed using receiver operating characteristic (AUROC) curve C statistics. ResultsThere were 443 patients, with a mean (±standard deviation) age of 64.8 (±18) years, 59% male. The median (interquartile ratio) Charlson Comorbidity score was 3 (0–6). Management included laparoscopic (n = 307, 69.3%), open (n = 26, 6%), laparoscopy converted to laparotomy (n = 53, 12%), and cholecystostomy (n = 57, 12.7%). Comparison of AAST with Tokyo Guidelines AUROC C statistics indicated (P < .05) mortality (0.86 vs 0.73), complication (0.76 vs 0.63), and cholecystostomy tube utilization (0.80 vs 0.68). ConclusionEmergency general surgery grading systems improve disease severity assessment, may improve documentation, and guide management. Discrimination of disease severity using the AAST grading system outperforms the Tokyo Guidelines for key clinical outcomes. The AAST grading system requires prospective validation and further comparison.

Assessment of blunt splenic trauma: Which imaging scoring system is superior?

Background:Spleen is the most common viscera that may be hurt in blunt abdominal trauma. Operative or nonoperative management of splenic injury is a dilemma. The American Association for the Surgery of Trauma (AAST) is the most common grading system which has been used for the management of blunt splenic injuries. The new recommended grading system assesses other aspects of splenic injury such as contrast extravasation, pseudoaneurysm, arteriovenous fistula, and severity of hemoperitoneum, as well. The aim of this study is to compare and prioritize the cutoff of AAST grading system with the new recommended one.Materials and Methods:This is a cross-sectional study on patients with splenic injury caused by abdominal blunt trauma referred to Isfahan University of Medical Sciences affiliated Hospitals, Iran, in 2013–2016. All patients underwent abdominopelvic computed tomography scanning with intravenous (IV) contrast. All images were reported by a single expert radiologist, and splenic injury grading was reported based on AAST and the new recommended system. Then, all patients were followed to see if they needed surgical or nonsurgical management.Results:Based on the findings of this study conducted on 68 patients, cutoff point of Grade 2, in AAST system, had 90.3% (95% confidence interval [CI]: 0.73–0.97) specificity, 51.4% (95% CI: 0.34–0.67) sensitivity, 86.4% (95% CI: 0.64–0.95) positive predictive value (PPV), and 60.9% (95% CI: 0.45–0.74) negative predictive value (NPV) for prediction of surgical management requirement, while it was 90.3% (95% CI: 0.73–0.97) specificity, 45.9% (95% CI: 0.29–0.63) sensitivity, 85% (95% CI: 0.61–0.96) PPV, and 58.3% (95% CI: 0.43–0.72) NPV for the new system (P = 0.816).Conclusion:In contrast to the previous studies, the new splenic injury grading method was not superior to AAST. Further studies with larger populations are recommended.

Increased anatomic severity predicts outcomes: Validation of the American Association for the Surgery of Trauma's Emergency General Surgery score in appendicitis.

Determination and reporting of disease severity in emergency general surgery lacks standardization. Recently, the American Association for the Surgery of Trauma (AAST) proposed an anatomic severity grading system. We aimed to validate this system in patients with appendicitis and determine if cross-sectional imaging correlates with disease severity at operation. Patients 18 years or older undergoing treatment for acute appendicitis between 2013 and 2015 were identified. Baseline demographics, procedure types were recorded, and AAST grades were assigned based on intraoperative and radiologic findings. Outcomes including length of stay, 30-day mortality, and complications based on Clavien-Dindo categories and National Surgical Quality Improvement Program variables. Summary statistical univariate, nominal logistic, and standard least squares analyses were performed comparing AAST grade with key outcomes. Bland-Altman analysis compared operative findings with preoperative cross-sectional imaging to compare assigning grades. Three hundred thirty-four patients with mean (±SD) age of 39.3 years (±16.5) were included (53% men), and all patients had cross-sectional imaging. Two hundred ninety-nine underwent appendectomy, and 85% completed laparoscopic. Thirty-day mortality rate was 0.9%, complication rate was 21%. Increased (median [interquartile range, IQR]) AAST grade was recorded in patients with complications (2 [1-4]) compared with those without (1 [1-1], p = 0.001). For operative management, (median [IQR]) AAST grades were significantly associated with procedure type: laparoscopic (1 [1-1]), open (4 [2-5]), conversion to open (3 [1-4], p = 0.001). Increased (median [IQR]) AAST grades were significantly associated in nonoperative management: patients having a complication had a higher median AAST grade (4 [3-5]) compared with those without (3 [2-3], p = 0.001). Bland-Altman analysis comparing AAST grade and cross-sectional imaging demonstrated no difference (-0.02 ± 0.02; p = 0.2; coefficient of repeatability 0.9). The AAST grading system is valid in our population. Increased AAST grade is associated with open procedures, complications, and length of stay. The AAST emergency general surgery grade determined by preoperative imaging strongly correlated to operative findings. Epidemiologic/prognostic study, level III.

Imaging characteristics associated with failure of nonoperative management in high-grade pediatric blunt renal trauma

Some children who sustain high-grade blunt renal injury may require operative intervention. In the present study, it was hypothesized that there are computed tomography (CT) characteristics that can identify which of these children are most likely to need operative intervention. A retrospective review was performed of all pediatric blunt renal trauma patients at a single level-I trauma center from 1990 to 2015. Inclusion criteria were: children with American Association for the Surgery of Trauma (AAST) Grade-IV or V renal injuries, aged ≤18 years, and having available CT images with delayed cuts. The CTs were regraded according to the revised AAST grading system proposed by Buckley and McAninch in 2011. Radiographic characteristics of renal injury were correlated with the primary outcome of any operative intervention: ureteral stent, angiography, nephrectomy/renorrhaphy, and percutaneous nephrostomy/drain. One patient had a Grade-V injury and 26 patients had Grade-IV injuries. Nine patients (33.3%) underwent operative interventions. Patients in the operative intervention cohort were more likely to manifest a collecting system filling defect (P=0.040) (Fig. A) and lacked ureteral opacification (P=0.010). The CT characteristics, including percentage of devascularized parenchyma, medial contrast extravasation, intravascular contrast extravasation, perirenal hematoma distance and laceration location, were not statistically significant. Of the 21 patients who had a collecting system injury, eight (38.1%) needed ureteral stents. Renorrhaphy was necessary for one patient. Although the first operative intervention occurred at a median of hospital day 1 (range 0.5-2.5), additional operative interventions occurred from day 4-16. Thus, it is prudent to closely follow-up these patients for the first month after injury. Two patients with complex renal injuries had an accessory renal artery resulting in well-perfused upper and lower pole fragments, and were managed nonoperatively without readmission (Fig. B). Collecting system defects and lack of ureteral opacification were significantly associated with failure of nonoperative management. A multicenter trial is needed to confirm these findings and whether nonsignificant CT findings are associated with operative intervention. In the month after renal injury, these patients should be mindful of any changes in symptoms, and maintain a low index of suspicion for an emergency room visit. For the physician, close follow-up and appropriate counseling of these high-risk patients is advised.

Organ laceration grading adherence by radiologists.

American Association for the Surgery of Trauma (AAST) abdominopelvic organ laceration grading is used to determine which patients can be managed non-operatively. We assess a change in the use of AAST grading system by radiologists at a single, large, academic institution before and after a one-time departmental intervention and reviewed non-graded reports evaluating if grading could be inferred. After IRB approval, a keyword search for "laceration" identified traumatic abdominopelvic CT reports in a 2-year period before and after the one-time intervention. Reports were reviewed to determine if an organ laceration was seen, if it was graded by AAST criteria, and if grading could be inferred for non-graded reports. T test was performed to assess statistical significance. Before the intervention, 348 reports contained the keyword "laceration," 81 with lacerations, 31 graded (38 %). After the intervention, 302 reports were found, 79 with lacerations, 59 graded (75 %). The increase was statistically significant (p < 0.0001). A decreasing trend in grading was seen over time following the intervention. Two out of 50 (4 %) pre-intervention and four out of 20 (20 %) post-intervention reports gave enough detailed descriptions for the grading to be inferred when it was not explicitly stated. Non-graded reports did not describe laceration parenchymal depth and subcapsular hematoma surface area percentage; however, the presence/absence of active extravasation, omitted in the 20-year-old AAST grading scheme, was described in every report. One-time departmental intervention yielded a significant increase in adherence to AAST laceration grading. Lack of perfect compliance, which diminished over time, suggests a need for further reinforcement.

External Validation of a Substratification of the American Association for the Surgery of Trauma Renal Injury Scale for Grade 4 Injuries

The traditional American Association for the Surgery of Trauma (AAST) grading of renal injury does not adequately identify the subset of patients who are most likely to require intervention for bleeding. Recently, several high-risk criteria (HRC) for bleeding after renal injury were identified, and we sought to externally validate these criteria among patients with grade 4 renal injury. All patients presenting to a level I trauma center with blunt grade 4 renal injuries from 2003 to 2010 were reviewed, and stage was determined by the 1989 AAST staging criteria. Dependent variables included the presence of a hilar injury or any of the HRC (perirenal hematoma size, intravascular contrast extravasation, and medial or complex laceration). The primary outcome was the need for intervention (renorrhaphy, nephrectomy, or angiography) for hemodynamic instability. A total of 84 patients with grade 4 renal lacerations were identified. Two or more HRC were present in 18 patients (21%), and intervention for hemodynamic instability was performed in 14 patients (17%). Compared with patients with 0 or 1 HRC, those with ≥ 2 HRC were approximately 25 times more likely to require intervention for hemodynamic instability (odds ratio [OR]24.9, 95% CI 5.5 to 112.9, p < 0.001). Patients with no HRC were unlikely to require intervention for hemodynamic instability. Among patients with blunt grade 4 renal injury, the presence of ≥ 2 HRC effectively predicts the need for intervention for hemodynamic instability and can be used to identify patients who require intensive monitoring. The AAST grading system for renal injury should be modified to better reflect injury severity.

Reliability of injury grading systems for patients with blunt splenic trauma

ObjectivesThe most widely used grading system for blunt splenic injury is the American Association for the Surgery of Trauma (AAST) organ injury scale. In 2007 a new grading system was developed. This ‘Baltimore CT grading system’ is superior to the AAST classification system in predicting the need for angiography and embolization or surgery. The objective of this study was to assess inter- and intraobserver reliability between radiologists in classifying splenic injury according to both grading systems. MethodsCT scans of 83 patients with blunt splenic injury admitted between 1998 and 2008 to an academic Level 1 trauma centre were retrospectively reviewed. Inter and intrarater reliability were expressed in Cohen's or weighted Kappa values. ResultsOverall weighted interobserver Kappa coefficients for the AAST and ‘Baltimore CT grading system’ were respectively substantial (kappa=0.80) and almost perfect (kappa=0.85). Average weighted intraobserver Kappa's values were in the ‘almost perfect’ range (AAST: kappa=0.91, ‘Baltimore CT grading system’: kappa=0.81). ConclusionThe present study shows that overall the inter- and intraobserver reliability for grading splenic injury according to the AAST grading system and ‘Baltimore CT grading system’ are equally high. Because of the integration of vascular injury, the ‘Baltimore CT grading system’ supports clinical decision making. We therefore recommend use of this system in the classification of splenic injury.

67 CONTEMPORARY EVALUATION AND MANAGEMENT OF 111 HIGH-GRADE BLUNT RENAL INJURIES

You have accessJournal of UrologyTrauma/Reconstruction: Trauma & Reconstructive Surgery II1 Apr 201067 CONTEMPORARY EVALUATION AND MANAGEMENT OF 111 HIGH-GRADE BLUNT RENAL INJURIES Thomas Smith, Hunter Wessells, and Bryan Voelzke Thomas SmithThomas Smith Houston, TX More articles by this author , Hunter WessellsHunter Wessells Seattle, WA More articles by this author , and Bryan VoelzkeBryan Voelzke Seattle, WA More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2010.02.114AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Blunt trauma is the most common form of injury to the kidney. American Association for the Surgery of Trauma (AAST) low-grade renal injuries (I-III) are typically managed conservatively; however, high-grade blunt renal injury (IV-V) lacks standardized management. We analyzed our extensive experience with high-grade blunt renal injuries to evaluate contemporary management and outcome. METHODS From 2003-2007, 111 consecutive patients presented to Harborview Medical Center with blunt grade IV-V renal injury. Initial evaluation included vital signs, Glasgow Coma Score, laboratory evaluation, and contrast CT of the abdomen/pelvis with delayed images. Each CT was retrospectively evaluated by urology staff (TS, BV) using the AAST grading system. In patients with grade III or higher injury, repeat CT with delayed images was performed 36-48 hours later. Follow-up included clinical exam, creatinine, and imaging (CT, ultrasound, or functional studies). RESULTS Patient mean age was 33.3 years and 67.6% were male. Median length of hospitalization was 6 days (0-73). In the 111 patients, there were 104 grade IV and 7 grade V injuries. Among the grade IV cohort, intervention was performed in 32 (19 minimally invasive, 13 operative). Renal salvage for AAST IV renal injury was 96% (100/104). In patients with AAST grade V injury, 6 procedures were performed including 5 nephrectomies. 16 patients required ureteral stents and additional percutaneous drainage was required in 6. Overall mortality for the entire cohort was 7.3% (8/111). After discharge, 52 patients returned for follow-up. Nuclear medicine imaging was performed in 35 at a mean of 105 days after discharge. Acceptable renal function, > 20%, was noted in 32. No patient had evidence of hypertension. CONCLUSIONS High-grade blunt renal trauma is a complex management issue. Most injuries can be managed conservatively, however, a low threshold for intervention is necessary. Partial nephrectomy, while more challenging, is technically feasible. Despite the heterogeneous nature of this patient population, high renal salvage rates are achievable and should be sought when clinical status dictates. Renal salvage is more difficult in grade V injuries reflecting both the severity of the renal injury and the injury severity of the patient. Management Interventions AAST injury grade N Angiography Embolization Stent Exploration Partial Nephrectomy Total Nephrectomy IV parenchyma 77 4 15 3 6 4 IV vascular 27 1 1 1 V parenchyma 4 4 V vascular 3 1 1 Total 111 1 6 16 3 6 9 © 2010 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 183Issue 4SApril 2010Page: e28-e29 Peer Review Report Advertisement Copyright & Permissions© 2010 by American Urological Association Education and Research, Inc.MetricsAuthor Information Thomas Smith Houston, TX More articles by this author Hunter Wessells Seattle, WA More articles by this author Bryan Voelzke Seattle, WA More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Only Moderate Intra- and Inter-observer Agreement between Radiologists and Surgeons when Grading Blunt Paediatric Hepatic Injury on CT Scan

The American Pediatric Surgical Association developed guidelines for the management of haemodynamically stable children with hepatic or splenic injury, based on grade of injury on CT scan. This study investigated the intra- and inter-observer agreement of radiologists, paediatric surgeons, trauma surgeons and hepatobiliary surgeons when scoring liver injury based on CT scan findings. CT scans of patients with blunt abdominal trauma were independently assessed twice by a fellow and a consultant radiologist, paediatric surgeon, trauma surgeon and one consultant hepatobiliary surgeon. Reviewers were unaware of the clinical course. All scans were multislice CTs with a slice thickness of 3 mm, and both the arterial and venous phase were assessed. Injury was scored using the American Association for the Surgery of Trauma (AAST) liver injury scale. Intra-observer agreement was tested using Cohen's kappa coefficient. Inter-observer agreement was tested using Cohen's kappa for the second reading of individual observers and Spearman's rank correlation for the mean of both readings from each observer. CT scans of 27 patients (11 girls and 16 boys, median age 11.7+/-5.2 years) were reviewed. Mean AAST grade of liver injury was 3.3+/-1.1 for radiologists, 2.9+/-1.0 for paediatric surgeons, 3.0+/-0.9 for trauma surgeons and 3.2+/-0.8 for the hepatobiliary surgeon (p=0.30) Intra-observer agreement was moderate, with kappa below 0.7 for all observers except for one of the radiologists. Inter-observer correlation using Cohen's kappa coefficient was also moderate, with kappa below 0.5. In contrast, inter-observer correlation using Spearman's test was good, suggesting that there is agreement on the general severity of injury but not on the exact grading of injury using the AAST scoring system. Intra-observer agreement is only moderate when assessing liver injury using the AAST grading system. Only the most experienced radiologist demonstrated good intra-observer agreement which might indicate the necessity of the presence of a senior trauma radiologist at all times. However, this is not possible in most centres. Although there was agreement concerning the general severity of injury, inter-observer agreement is also moderate. These data cast doubt on the use of the AAST liver injury score alone as a decision-making tool when assessing haemodynamically stable children with blunt hepatic injury.

A clinically relevant liver injury grading system by CT, preliminary report

Current computed tomography (CT) grading scales are anatomic and do not reliably identify those liver injuries requiring intervention (surgery or angioembolization). We propose a clinically relevant CT grading system that could predict need for intervention. CT scans of 11 patients with hepatic injury were reviewed to establish criteria that correspond with intervention. Five features were identified that were associated with intervention: laceration in greater than or equal to three segments, laceration extending into the hilum, hemoperitoneum, active extravasation, and sentinel clot. Radiologists then evaluated the predictability of these criteria by analyzing 24 CT scans. Inter-observer agreement of the American Association for the Surgery of Trauma (AAST) grading system was compared to this new system. In the analysis of 24 CT scans, active extravasation and sentinel clot demonstrated the highest specificity for intervention. This new grading system had superior inter-observer agreement (k=0.56) as compared to the AAST grading system (k=0.47). Active extravasation and the presence of sentinel clot should form the foundation of a new liver grading system.