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

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.

Iterative reconstruction improves image quality and reduces radiation dose in trauma protocols; A human cadaver study

Background

Radiation-related cancer risk is an object of concern in CT of trauma patients, as these represent a young population. Different radiation reducing methods, including iterative reconstruction (IR), and spilt bolus techniques have been introduced in the recent years in different large scale trauma centers.

Purpose

To compare image quality in human cadaver exposed to thoracoabdominal computed tomography using IR and standard filtered back-projection (FBP) at different dose levels.

Material and methods

Ten cadavers were scanned at full dose and a dose reduction in CTDIvol of 5 mGy (low dose 1) and 7.5 mGy (low dose 2) on a Siemens Definition Flash 128-slice computed tomography scanner. Low dose images were reconstructed with FBP and Sinogram affirmed iterative reconstruction (SAFIRE) level 2 and 4. Quantitative image quality was analyzed by comparison of contrast-to-noise ratio (CNR) and signal-to-noise ratio (SNR). Qualitative image quality was evaluated by use of visual grading regression (VGR) by four radiologists.

Results

Readers preferred SAFIRE reconstructed images over FBP at a dose reduction of 40% (low dose 1) and 56% (low dose 2), with significant difference in overall impression of image quality. CNR and SNR showed significant improvement for images reconstructed with SAFIRE 2 and 4 compared to FBP at both low dose levels.

Conclusions

Iterative image reconstruction, SAFIRE 2 and 4, resulted in equal or improved image quality at a dose reduction of up to 56% compared to full dose FBP and may be used a strong radiation reduction tool in the young trauma population.

Utility of enteric contrast material in abdominal penetrating trauma: A narrative review

Penetrating trauma is an important cause of morbidity and mortality. With the possibility of conservative management for hemodynamically stable trauma patient, computed tomography (CT) has become an important tool in diagnosis and management of penetrating trauma. There have been multiple studies examining the utility and lack of perceived benefit of using enteric contrast material in the initial CT evaluation. We provide a narrative review of the surgical and radiological literature, offer our own protocol for how to approach the imaging of patients with suspected bowel injury following penetrating traumatic injury and discuss the potential of using enteric contrast material.

Whole-body computed tomography is safe, effective and efficient in the severely injured hemodynamically unstable trauma patient

Trauma is a complex pathology that requires an experienced multidisciplinary team with an inherent quick decision-making capacity, given that a few minutes could represent a matter of life or death. These management decisions not only need to be quick but also accurate to be able to prioritize and to efficiently control the injuries that may be causing impending hemodynamic collapse. In essence, this is the cornerstone of the concept of damage control trauma care. With current technological advances, physicians have at their disposition multiple diagnostic imaging tools that can aid in this prompt decision-making algorithm. This manuscript aims to perform a literature review on this subject and to share the experience on the use of whole body computed tomography as a potentially safe, effective and efficient diagnostic tool in cases of severely injured trauma patients regardless of their hemodynamic status. Our general recommendation is that, when feasible, perform a whole body computed tomography without interrupting ongoing hemostatic resuscitation in cases of severely injured trauma patients with or without signs of hemodynamic instability. The use of this technology will aid in the decision-making of the best surgical approach for these patients without incurring any delay in definitive management and/or increasing significantly their radiation exposure.

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 vs. multiphasic contrast bolus protocol in patients with pancreatic cancer or cholangiocarcinoma

PURPOSE

To investigate the image quality, diagnostic accuracy, and dose reduction potential of a split-bolus protocol(SBP) compared with a multiphasic protocol(MPP) in the detection of recurrent or progressive pancreatic ductal adenocarcinoma(PDAC) or cholangiocarcinoma(CC) using contrast- enhanced computed tomography(CECT).

MATERIALS AND METHODS

This prospective study included 56 patients who underwent CECT, 28 with our institutional standard MPP(100 ml contrast bolus) and 28 with a novel SBP(110 ml). Radiation exposure was determined in terms of total dose- length product(DLP) and computed tomography dose index(CTDI). Image quality was measured objectively by analysis of attenuation in Hounsfield units(HU) in regions of interest(ROIs) and subjectively by two blinded readers using a Likert scale. Diagnostic accuracy and interreader variability were tested.

RESULTS

The total DLP of the SBP group(498.1 ± 43.7 mGy*cm) was significantly lower than in the MPP group(1,092.5 ± 106.9 mGy*cm; p < 0.001). The SBP showed higher contrast enhancement of all critical anatomical structures including portal vein, liver, and pancreas compared with the MPP, except for the aorta(SBP: 326.9 ± 15.7 HU vs. MPP: 246.7 ± 12.2 HU; p < 0.001). Subjective analysis revealed poorer image quality ratings for important landmarks with the MPP (resection surface: p = 0.624, portal vein: p = 0.395, liver p = 0.361). The two blinded readers correlated significantly. Sensitivity, specificity, positive and negative predictive values (PPV/NPV), and overall interreader variabilities correlated significantly. Furthermore, significantly fewer slices per exam were required for the SBP(1,823 vs. 3,235; p < 0.001).

CONCLUSION

The SBP provides the same image quality and diagnostic accuracy as an MPP while significantly lowering radiation exposure in CT follow-up of PDAC or CC.