Implementation of a split-bolus single-pass CT protocol at a UK major trauma centre to reduce excess radiation dose in trauma pan-CT

Self-harm, suicide and brain death: the role of the radiologist

Suicide is a leading cause of death worldwide and takes many forms, which include hanging, jumping from a height, sharp force trauma, ingestion/poisoning, drowning, and firearm injuries. Self-harm and suicide are associated with particular injuries and patterns of injury. Many of these patterns are apparent on imaging. Self-harm or suicidal intent may be overlooked initially in such cases, particularly when the patient is unconscious or uncooperative. Correct identification of these findings by the radiologist will allow a patient's management to be tailored accordingly and may prevent future suicide attempts. The initial role of the radiologists in these cases is to identify life-threatening injuries that require urgent medical attention. The radiologist can add value by drawing attention to associated injuries, which may have been missed on initial clinical assessment. In many cases of self-harm and suicide, imaging is more reliable than clinical assessment. The radiologist may be able to provide important prognostic information that allows clinicians to manage expectations and plan appropriately. Furthermore, some imaging studies will provide essential forensic information. Unfortunately, many cases of attempted suicide will end in brain death. The radiologist may have a role in these cases in identifying evidence of hypoxic-ischaemic brain injury, confirming a diagnosis of brain death through judicious use of ancillary tests and, finally, in donor screening for organ transplantation. A review is presented to illustrate the imaging features of self-harm, suicide, and brain death, and to highlight the important role of the radiologist in these cases.

Split-bolus single-phase versus single-bolus split-phase CT acquisition protocols for staging in patients with testicular cancer: A retrospective study

INTRODUCTION

Computed tomography (CT) imaging has become indispensable in the management of medical oncology patients. Risks associated with high cumulative effective dose (CED) are relevant in testicular cancer patients. Split-bolus protocols, whereby the contrast medium injection is divided into two, followed by combining the required phase images in a single scan acquisition has been shown to provide images of comparable image quality and less radiation dose compared to single-bolus split-phase CT for various indications. We retrospectively evaluated the performance of split-bolus and single-bolus protocols in patients having follow-up CT imaging for testicular cancer surveillance.

METHODS

45 patients with testicular cancer undergoing surveillance CT imaging of the thorax, abdomen, and pelvis who underwent split-bolus and single-bolus protocols were included. Quantitative image quality analysis was conducted by placing region of interests in pre-defined anatomical sub-structures within the abdominal cavity. The signal-to-noise ratio (SNR) and radiation dose in the form of dose length product (DLP) and effective dose (ED) were recorded.

RESULTS

The DLP and ED for the single-bolus, split-phase acquisition was 506 ± 89 mGy cm and 7.59 ± 1.3 mSv, respectively. For the split-bolus, single-phase acquisition, 397 ± 94 mGy∗cm and 5.95 ± 1.4 mSv, respectively (p < 0.000). This represented a 21.5 % reduction in radiation dose exposure. The SNR for liver, muscle and fat for the single-bolus were 7.4, 4.7 and 8, respectively, compared to 5.5, 3.8 and 7.4 in the split-bolus protocol (p < 0.001).

CONCLUSION

In a testicular cancer patient cohort undergoing surveillance CT imaging, utilization of a split-bolus single-phase acquisition CT protocol enabled a significant reduction in radiation dose whilst maintaining subjective diagnostic acceptability.

IMPLICATIONS FOR PRACTICE

Use of split-bolus, single-phase acquisition has the potential to reduce CED in surveillance of testicular cancer patients.

Can the use of whole-body CT be reduced in cases of kinetic-based polytrauma patients without a clinical severity criterion? A bi-center retrospective study

OBJECTIVE

To identify clinical and biological criteria predictive of significant traumatic injury in only kinetic-based polytrauma patients without clinical severity criteria. To propose a decisional algorithm to assist the emergency doctor in deciding whether or not to perform a WBCT in the above population.

METHODS

Retrospective bi-center study. 1270 patients with high velocity trauma without clinical severity criteria, for whom a WBCT was performed in 2017, were included. Patients with hemodynamic, respiratory or neurological severity criterion or those requiring pre-hospital resuscitation measures were excluded. Our primary endpoint was the identification of a significant lesion, i.e. any lesion that led to hospitalization > 24 h for monitoring or medico-surgical treatment. Data collected were age, sex, mechanism of injury, Glasgow Coma Scale score, number of symptomatic body regions, blood alcohol level, and neutrophil count.

RESULTS

Multivariate analysis found independent predictors of significant injury: fall > 5 m (OR: 14.36; CI: 2.3-283.4; p = 0.017), Glasgow score = 13 or 14 (OR: 4.40; CI:1.30-18.52; p = 0.027), presence of 2 symptomatic body regions (OR: 10.21; CI: 4.66-23.72; p = 0.05), positive blood alcohol level (OR: 2.81; CI: 1.13-7.33; p = 0.029) and neutrophilic leukocytosis (OR: 8.76; CI: 3.94-21.27; p = 0.01). A composite clinico-biological endpoint predictive of the absence of significant lesion was identified using a Classification and Regression Tree: number of symptomatic regions < 2, absence of Neutrophilic leukocytosis and negative blood alcohol concentration.

CONCLUSION

A simple triage algorithm was created with the objective of identifying, in high velocity trauma without clinical severity criteria, those without significant traumatic injury.

Avoiding immediate whole-body trauma CT: a prospective observational study in stable trauma patients

High energy blunt trauma patients with normal vital signs are usually investigated with a Contrast Enhanced Computed Tomography (CECT) for torso injuries. CECT involves high levels of radiations, often showing no injuries in patients over-triaged to the trauma center. The aim of our study was to suggest an alternative diagnostic protocol based on Emergency Room (ER) tests (physical exam, blood tests, extended FAST, Chest and Pelvis X-ray) to avoid CECT in selected patients. A prospective cohort study was conducted from September 2018 to September 2019. Five hundred patients fulfilled the inclusion criteria. Patients received torso-CECT scan only if they had at least one positive ER test. The validity of the single component of the protocol and the global validity of the ER tests to detect torso injuries was assessed through sensitivity, specificity, positive (PPV) and negative (NPV) predictive value, positive (+ LR) and negative (- LR) likelihood ratio. Multivariate analysis was performed to identify independent predictors of torso injuries. One hundred and seventy patients received a torso-CECT scan because of positive ER tests. ER tests showed a global sensitivity for torso injuries of 86.96% (95% CI 80.17-92.08) specificity of 83.98%(95% CI 79.79-87.60), PPV of 67.42% (95% CI 61.83-72.54), NPV of 94.41% (95% CI 91.63-96.30) + LR of 5.43 (95% CI 4.25-6.93), - LR of 0.16 (95% CI 0.10-0.24). ER tests in an experienced center seem to be able to identify more severe blunt trauma patients needing CECT. Further studies are advisable to confirm these results.

How to deliver an effective primary survey report for the trauma CT: A radiological and surgical perspective

Whole body contrast-enhanced multidetector CT (WB-CE MDCT) is integral to the assessment of the severely injured patient with stable haemodynamic parameters or in those who respond to resuscitation with blood products. WB-CE MDCT is able to identify the number and severity of injuries sustained by the patient and enable time critical intervention.

In this narrative review article we discuss how communication within the trauma team, including the radiologists and appropriate clinicians is crucial in optimizing the effectiveness of WB-CE MDCT. We review the time critical imaging findings and their clinical relevance, which should be included in a succinct CT primary survey report.

We also discuss the process through which the effectiveness of the trauma report may be maximised and how non technical factors including teamwork may be optimised to facilitate decision making in this high pressure environment.

Deep learning reconstruction for contrast-enhanced CT of the upper abdomen: similar image quality with lower radiation dose in direct comparison with iterative reconstruction

OBJECTIVE

To evaluate the effect of a commercial deep learning algorithm on the image quality of chest CT, focusing on the upper abdomen.

METHODS

One hundred consecutive patients who simultaneously underwent contrast-enhanced chest and abdominal CT were collected. The radiation dose was optimized for each scan (mean CTDI_vol: chest CT, 3.19 ± 1.53 mGy; abdominal CT, 7.10 ± 1.88 mGy). Three image sets were collected: chest CT reconstructed with an adaptive statistical iterative reconstruction (ASiR-CHT; 50% blending), chest CT with a deep learning algorithm (DLIR-CHT), and abdominal CT with ASiR (ASiR-ABD; 40% blending). Afterwards, the images covering the upper abdomen were extracted, and image noise, the signal-to-noise ratio (SNR), and the contrast-to-noise ratio (CNR) were measured. For subjective evaluation, three radiologists independently assessed noise, spatial resolution, presence of artifacts, and overall image quality. Additionally, readers selected the most preferable reconstruction technique among three image sets for each case.

RESULTS

The average measured noise for DLIR-CHT, ASiR-CHT, and ASiR-ABD was 8.01 ± 2.81, 14.8 ± 2.56, and 12.3 ± 2.28, respectively (p < .001). Deep learning-based image reconstruction (DLIR) also showed the best SNR and CNR (p < .001). However, in the subjective analysis, ASiR-ABD showed less subjective noise than DLIR (2.94 ± 0.23 vs. 2.87 ± 0.26; p < .001), while DLIR showed better spatial resolution (2.60 ± 0.34 vs. 2.44 ± 0.31; p = .02). ASiR-ABD showed a better overall image quality (p = .001), but two of the three readers preferred DLIR more frequently.

CONCLUSION

With < 50% of the radiation dose, DLIR chest CT showed comparable image quality in the upper abdomen to that of dedicated abdominal CT and was preferred by most readers.

KEY POINTS

• With < 50% radiation dose, a deep learning algorithm applied to contrast-enhanced chest CT exhibited better image noise and signal-to-noise ratio than standard abdominal CT with the ASiR technique. • Pooled readers mostly preferred deep learning algorithm-reconstructed contrast-enhanced chest CT reconstructed using a standard ASiR-reconstructed abdominal CT. • Reconstruction algorithm-induced distortion artifacts were more frequently observed on deep learning algorithm-reconstructed images, but diagnostic difficulty was reported in only 0.3% of cases.

European Society of Emergency Radiology: guideline on radiological polytrauma imaging and service (short version)

BACKGROUND

Although some national recommendations for the role of radiology in a polytrauma service exist, there are no European guidelines to date. Additionally, for many interdisciplinary guidelines, radiology tends to be under-represented. These factors motivated the European Society of Emergency Radiology (ESER) to develop radiologically-centred polytrauma guidelines.

RESULTS

Evidence-based decisions were made on 68 individual aspects of polytrauma imaging at two ESER consensus conferences. For severely injured patients, whole-body CT (WBCT) has been shown to significantly reduce mortality when compared to targeted, selective CT. However, this advantage must be balanced against the radiation risk of performing more WBCTs, especially in less severely injured patients. For this reason, we recommend a second lower dose WBCT protocol as an alternative in certain clinical scenarios. The ESER Guideline on Radiological Polytrauma Imaging and Service is published in two versions: a full version (download from the ESER homepage, https://www.eser-society.org ) and a short version also covering all recommendations (this article).

CONCLUSIONS

Once a patient has been accurately classified as polytrauma, each institution should be able to choose from at least two WBCT protocols. One protocol should be optimised regarding time and precision, and is already used by most institutions (variant A). The second protocol should be dose reduced and used for clinically stable and oriented patients who nonetheless require a CT because the history suggests possible serious injury (variant B). Reading, interpretation and communication of the report should be structured clinically following the ABCDE format, i.e. diagnose first what kills first.

Split-Bolus, Single-Acquisition, Dual-Phase Abdominopelvic CT Angiography for the Evaluation of Lung Transplant Candidates: Image Quality and Resource Utilization

OBJECTIVE. The purpose of this study was to assess the image quality and resource utilization of single-injection, split-bolus, dual-enhancement abdominopelvic CT angiography (hereafter referred to as dual-enhancement CTA) performed for combined vascular and solid organ assessment compared with those of single-injection, single-enhancement abdominopelvic CT angiography (hereafter referred to as single-enhancement CTA) for vascular assessment in combination with additional examinations (CT, MRI, and US) performed to assess for malignancy in lung transplant candidates. MATERIALS AND METHODS. We retrospectively reviewed 100 patients who underwent abdominopelvic CTA examinations before lung transplant. Cohort A (n = 50) underwent dual-enhancement CTA and cohort B (n = 50) underwent single-enhancement CTA. Contrast opacification of the vasculature was assessed along the abdominal aorta through the right femoral artery. Solid organ enhancement was assessed in the right lobe of the liver and the right renal cortex. Measurements of mean radiation dose, contrast exposure, and cost of the studies (in U.S. dollars) were compared. RESULTS. Mean (± SD) vascular enhancement on dual-enhancement CTA and single-enhancement CTA was 334.2 ± 26.5 HU (coefficient of variation, 8.3%) and 340.0 ± 21.6 HU (coefficient of variation, 6.5%) (p = 0.23), respectively. For dual-enhancement CTA and single-enhancement CTA, mean liver enhancement was 125.8 ± 30.5 HU and 60.4 ± 6.9 HU (p < 0.01), respectively, whereas mean renal cortical enhancement was 260.3 ± 62.2 HU and 133.4 ± 38.6 HU (p < 0.01), respectively. The mean IV contrast volume was 150 mL for dual-enhancement CTA and 75 mL for single-enhancement CTA. Cohort A underwent six additional imaging studies (one of which was a CT colonography study with an effective dose of 19.0 mSv) at a total cost of $9840 per patient. Cohort B underwent 44 additional imaging studies (mean effective dose, 12.7 ± 6.5 mSv) at a total cost of $12,846 per patient (resulting in a 30.6% reduction in cost for dual-enhancement CTA studies; p < 0.0001). CONCLUSION. Dual-enhancement abdominopelvic CTA allows combined vascular and abdominopelvic solid organ assessment with improved image quality and a lower cost compared with traditional imaging pathways.

[Update polytrauma and computed tomography in ongoing resuscitation : ABCDE and "diagnose first what kills first"]

CLINICAL ISSUE

The mean number of trauma room admissions and applied CT dose increase as the severity of injuries decreases. Therefore, appropriateness of established procedures should be re-evaluated.

STANDARD RADIOLOGICAL METHODS

Considering severely injured patients with an Injury Severity Score (ISS) ≥16, whole body CT (WB-CT) compared to selective CT decreased mortality by about 25%. Thus, the ISS is a good indicator for the severity of injuries. However, since ISS can only be determined after diagnosis, it does not help with the primary assessment.

METHODOLOGICAL INNOVATION AND EVALUATION

In addition to the currently used very fast WB-CT protocol with the highest diagnostic precision, a second protocol should be established applying a substantially lower dose. Under ongoing resuscitation, WB-CT often makes a substantial contribution towards targeted therapy or to justifying the discontinuation of resuscitation measures. The WB-CT findings should be performed several times and, at least in the acute emergency situation, it should follow the ABCDE scheme as close as possible.

PRACTICAL RECOMMENDATIONS

In the trauma room it should be initially decided whether the classification as polytrauma is to be maintained. If yes, every institution should provide a dose-reduced WB-CT protocol in addition to the maximum variant used so far. Dose-reduced WB-CT seems to be appropriate for stable and oriented patients, who receive a CT primarily because of the trauma mechanism. Even under resuscitation conditions, WB-CT is easy to perform and medically as well as ethically of high value. The reporting and communication should be structured according to "diagnose first what kills first".

Split-bolus single-pass CT for vascular complications in acute pancreatitis: assessment of radiation dose and multi-phasic contrast enhancement compared to single-bolus multi-pass CT

AIM

To assess vascular contrast enhancement and radiation dose of split-bolus single-pass computed tomography (CT) compared to single-bolus multi-pass CT for acquiring a multi-phasic study.

MATERIALS AND METHODS

Patients who underwent CT for acute pancreatitis were included retrospectively. Thirty consecutive patients scanned with a split-bolus protocol were compared to 30 consecutive patients scanned with a single-bolus protocol. Data were collected on attenuation measurements (aorta, portal vein and spleen) and images were assessed for subjective vascular enhancement quality and splenic homogeneity. Radiation dose was measured by dose-length product (DLP).

RESULTS

There was no significant difference in the aortic (p = 0.88) or portal vein (p = 0.35) attenuation values between the two groups. The percentage of examinations reaching the target aortic and portal attenuation in the split-bolus group were 96.7% and 93.3%, and in the single-bolus group were 96.7% and 85.7%, respectively. The mean DLP was 492 mGy.cm for the single-bolus group and 940 mGy.cm for the split-bolus group (p < 0.0001). Subjective assessment revealed higher rates of splenic heterogeneity in the split-bolus group.

DISCUSSION

In acute pancreatitis, split-bolus imaging can produce arterial and venous enhancement comparable to a multi-pass technique with a significant reduction in radiation dose. Loss of temporal resolution and increased splenic heterogeneity are the main disadvantages. The low prevalence of pseudoaneurysms favours the lower-dose imaging technique.

Multidetector CT Findings in the Abdomen and Pelvis after Damage Control Surgery for Acute Traumatic Injuries

After experiencing blunt or penetrating trauma, patients in unstable condition who are more likely to die of uncorrected shock than of incomplete injury repairs undergo emergency limited exploratory laparotomy, which is also known as damage control surgery (DCS). This surgery is part of a series of resuscitation steps, with the goal of stabilizing the patient's condition, with rapid surgical control of hemorrhage followed by supportive measures in the intensive care unit before definitive repair of injuries. These patients often are imaged with multidetector CT within 24-48 hours of the initial surgery. Knowledge of this treatment plan is critical to CT interpretation, because there are anatomic derangements and foreign bodies that would not be present in patients undergoing surgery for other reasons. Patients may have injuries beyond the surgical field that are only identified at imaging, which can alter the care plan. Abnormalities related to the resuscitation period such as the CT hypoperfusion complex and ongoing hemorrhage can be recognized at CT. Familiarity with these imaging and clinical findings is important, because they can be seen not only in trauma patients after DCS but also in other patients in the critical care setting. The interpretation of imaging studies can be helped by an understanding of the diagnostic challenges of grading organ injuries with surgical materials in place and the awareness of potential artifacts on images in these patients. Online supplemental material is available for this article. ^©RSNA, 2019 See discussion on this article by LeBedis .

Split-bolus CTA for mesenteric ischemia with a single scan opacifying arterial and mesenteric venous systems

OBJECTIVE

To evaluate the diagnostic accuracy of split-bolus single-scan computed tomography angiography (CTA) protocol for evaluation of acute mesenteric ischemia and alternate diagnoses.

MATERIALS AND METHODS

In this IRB-approved, HIPAA-compliant retrospective study, consecutive patients from 21 October 2016 to 6 May 2018 evaluated for mesenteric ischemia with split-bolus CTA (a single scan in concurrent arterial and portal venous phase) in a single tertiary academic institution were included. Intravenous contrast was administered on weight-based basis. Quantitative and qualitative assessments of superior mesenteric artery (SMA) and superior mesenteric vein (SMV) attenuation and patency were performed by two independent reviewers. CT imaging findings were correlated with clinical reference outcomes.

RESULTS

One hundred fifty-four patients (age 66.3 ± 14.1 years, BMI 27.3 ± 6, 86 (56%) female) were included. CTA studies were performed with a volumetric CT dose index of 15.9 ± 5.5 mSv and dose length product of 1042.9 ± 389.4 mGy cm. Average intravenous contrast volume administered was 164.3 ± 12.1 cc. SMA attenuation was 263.6 ± 92.4HU, SMV was 190 ± 50.2HU. Qualitative assessment of SMA and SMV showed good opacification in all patients. 17/154 (11%) patients were diagnosed on CT with mesenteric ischemia; in 6/154 (4%), CTA studies were indeterminate; in 131/154 (85%), CTA confidently ruled out mesenteric ischemia. Alternate diagnoses were made in 38/154 (25%) patients. Using composite clinical outcomes as a reference standard, sensitivity of split-bolus CTA protocol for diagnosis of mesenteric ischemia is 100% (95% CI 79-100%), and specificity is 99% (95% CI 96-100%).

CONCLUSIONS

Split-bolus CTA has high sensitivity and specificity for diagnosis of acute mesenteric ischemia.

KEY POINTS

• Split-bolus CTA protocol for mesenteric ischemia has great diagnostic accuracy with lower radiation exposure and fewer images to interpret compared with standard multiphasic CTA.

Multidetector CT Findings of Solid Organ Injury Based on 2018 Updated American Association for the Surgery of Trauma Organ Injury Scaling System

2018년에 새롭게 개정된 장기 손상척도는 이전 미국외상수술협회의 응급수술분류체계와 유사한 형식을 가지며, 고형장기 손상의 등급을 지정하는 기준을 영상(imaging), 수술(operative), 병리(pathologic) 세 가지 세트로 나누어 분류하였다. 2018년 개정에서 가장 중요한 변화는 거짓동맥류와 동정맥 누공을 포함한 혈관 손상의 다중검출CT (multidetector CT; 이하 MDCT) 소견을 정의하여 장기 손상척도에 통합한 것이다. 이전 장기 손상척도와 동일하게 세 가지 기준 중에 가장 높은 등급이 최종 등급이 된다. 또한 한 장기 내에 여러 개의 1등급 또는 2등급 소견이 있으면, 다발성 손상에 대해 3등급의 부여가 가능하다. 본 임상화보에서는 2018년 개정된 미국외상수술협회 장기 손상척도의 MDCT 소견을 소개하고자 한다.

Triple-split-bolus versus single-bolus CT in abdominal trauma patients: a comparative study

Background Split-bolus computed tomography (CT) is a recent development in trauma imaging. Instead of multiple scans in different contrast phases after a single contrast bolus, split-bolus protocols consist of one single scan of the thorax and abdomen after two or three contrast injections at different points of time. Purpose To evaluate and compare image quality and injury findings of a new triple-split-bolus CT (TS-CT) protocol of thorax and abdomen with those of a portal venous phase CT (PV-CT) in the same patient group. Material and Methods Trauma patients in 2009-2012 who underwent both the TS-CT initially and a PV-CT during the next six weeks were included. The TS-CT examination was performed as one CT run after application of three contrast boluses (total 175 mL) to enhance renal pelvis and urinary tract, the abdominal organs, and the large arterial vessels. The PV-CT had a fixed delay of 85 s. We measured attenuation in Hounsfield units (HU), evaluated possible organ injury and assessed image quality on a 5-point scale. Results Thirty-five patients were included. Attenuation measurements of major abdominal vessels, organs, and renal pelvis were significantly higher with the TS-CT protocol. Performance in organ injury diagnosis and image quality was equal in both protocols. Conclusion The overall performance of the TS-CT protocol is similar to the standard PV-CT. Excellent visualization of the arterial tree and the collecting system may eliminate the need for separate scans.

Evaluation of a single-pass with biphasic intravenous contrast medium injection CT protocol for the assessment of complications post-simultaneous pancreas-kidney transplant

AIM

To evaluate the use of a single-pass with biphasic intravenous contrast medium injection computed tomography (CT) protocol to provide diagnostic quality CT studies for the assessment of complications post-simultaneous pancreas-kidney transplant (SPK).

MATERIALS AND METHODS

This was an audit of practice and the need for informed consent was waived. The protocol was used in consecutive patients undergoing CT to exclude intra-abdominal sepsis post-SPK between June and December 2015. Single CT acquisition of the abdomen and pelvis was initiated 70 seconds after the start of biphasic contrast medium injection (66 ml at 1.2 ml/s, followed by 34 ml at 2.4 ml/s, 370 mg iodine/ml). The named transplant pancreas vessels were identified and the attenuation values of the blood within were measured. Diagnostic quality was confirmed if values were >211 HU and >80 HU in the arteries and veins, respectively.

RESULTS

Thirteen CT studies were performed in 10 patients. CT studies were excluded due to complete pancreatic necrosis, and transplant superior mesenteric artery (SMA) thrombus with pancreatic head ischaemia causing effacement of the transplant superior mesenteric vein (SMV). Diagnostic quality of the analysed CT studies were confirmed with mean attenuation value of blood >211 HU in the transplant pancreatic arteries (SMA=259.0±51.4 HU, splenic artery=245.3±37.5 HU), and >80 HU in the pancreatic veins (SMV=195.4±36.2 HU, splenic vein=185.1±54.2 HU).

CONCLUSION

Diagnostic quality CT studies were obtained using the single-pass CT protocol. Radiation exposure to patients may be reduced with this protocol, while permitting simultaneous assessment of parenchymal and vascular complications post-SPK.

Variability in Imaging Practices and Comparative Cumulative Effective Dose for Neuroblastoma and Nephroblastoma Patients at 6 Pediatric Oncology Centers

The purpose of this study was to estimate the cumulative effective dose (CED) from diagnosis and posttherapy computed tomographic (CT) scans performed on children treated for neuroblastoma or nephroblastoma (Wilms tumor) and to examine the different imaging practices used in 6 regional pediatric oncology centers between January 2010 and December 2013. We analyzed retrospectively the CT scan acquisition data in children aged 10 years or younger at diagnosis. The use of nonionizing imaging modalities was reported. The CT examinations of 129 children, with a mean age at diagnosis of 36 months, treated for 66 neuroblastomas and 63 nephroblastomas, were analyzed. The mean follow-up period was 28 months (minimum, 8 months, maximum, 41 mo). There were 600 CT scans, with a total of 1039 acquisitions. The mean CED from CT scans was 27 mSv (minimum=18.25, maximum=45). Abdominal CT examinations contributed 85% of the total CED. A median of 4.6 CT scans, 10.3 sonograms, and 0.4 magnetic resonance imaging examinations per child were performed. Our results suggest a reduction in radiation exposure but variability in the imaging modality choice and acquisition protocols. We emphasize the need for consensus and standardization in oncologic pediatric imaging procedures. When feasible, we encourage the substitution of nonionizing examinations for CT.

Automatic radiation dose monitoring for CT of trauma patients with different protocols: feasibility and accuracy

AIM

To demonstrate the feasibility and accuracy of automatic radiation dose monitoring software for computed tomography (CT) of trauma patients in a clinical setting over time, and to evaluate the potential of radiation dose reduction using iterative reconstruction (IR).

MATERIALS AND METHODS

In a time period of 18 months, data from 378 consecutive thoraco-abdominal CT examinations of trauma patients were extracted using automatic radiation dose monitoring software, and patients were split into three cohorts: cohort 1, 64-section CT with filtered back projection, 200 mAs tube current-time product; cohort 2, 128-section CT with IR and identical imaging protocol; cohort 3, 128-section CT with IR, 150 mAs tube current-time product. Radiation dose parameters from the software were compared with the individual patient protocols. Image noise was measured and image quality was semi-quantitatively determined.

RESULTS

Automatic extraction of radiation dose metrics was feasible and accurate in all (100%) patients. All CT examinations were of diagnostic quality. There were no differences between cohorts 1 and 2 regarding volume CT dose index (CTDIvol; p=0.62), dose-length product (DLP), and effective dose (ED, both p=0.95), while noise was significantly lower (chest and abdomen, both -38%, p<0.017). Compared to cohort 1, CTDIvol, DLP, and ED in cohort 3 were significantly lower (all -25%, p<0.017), similar to the noise in the chest (-32%) and abdomen (-27%, both p<0.017). Compared to cohort 2, CTDIvol (-28%), DLP, and ED (both -26%) in cohort 3 was significantly lower (all, p<0.017), while noise in the chest (+9%) and abdomen (+18%) was significantly higher (all, p<0.017).

CONCLUSION

Automatic radiation dose monitoring software is feasible and accurate, and can be implemented in a clinical setting for evaluating the effects of lowering radiation doses of CT protocols over time.