Cumulative radiation exposure from diagnostic imaging in intensive care unit patients

What proportion of CT scan patients are alive or deceased after 10 years?

PURPOSE

When discussing radiation risks for patients who undergo many CT examinations, some question the risks, believing that most of these patients are already very sick and likely to die within a few years, thus negating worry about radiation risk. This study seeks to evaluate the validity of this notion.

METHODS

In this retrospective single large-hospital study, patients who received CT exams in 2013 were sorted into four cumulative effective dose (CED) groups: Group A (>0 to <10 mSv), Group B (10 to <50 mSv), Group C (50 to < 100 mSv), and Group D (≥100 mSv). The death rates of patients in each group were analyzed, up to December 2023.

RESULTS

36,545 patients underwent CT examinations in 2013 (mean age, 56 ± 20 years, 51.4 % men). Death rates for all dose groups peaked in the year of imaging or 1 year after. At one year after imaging, Group D had 6.7 times and Group C had 4.3 times the death rate of Group A. However, a significant portion of these patients are alive after 10 years, with 1324/2756 patients (48.0 %) in Group C and 282/769 patients (36.7 %) in Group D with the potential to face radiation effects.

CONCLUSIONS

While it is true that patients receiving relatively higher doses (≥50 mSv) are more likely to die within the first two years of receiving such doses, nearly one-third to half remain alive a decade after their CT scans, potentially facing the effects of radiation. This knowledge may help policymakers and practitioners.

Computed Tomography Effective Dose and Image Quality in Deep Learning Image Reconstruction in Intensive Care Patients Compared to Iterative Algorithms

Deep learning image reconstruction (DLIR) algorithms employ convolutional neural networks (CNNs) for CT image reconstruction to produce CT images with a very low noise level, even at a low radiation dose. The aim of this study was to assess whether the DLIR algorithm reduces the CT effective dose (ED) and improves CT image quality in comparison with filtered back projection (FBP) and iterative reconstruction (IR) algorithms in intensive care unit (ICU) patients. We identified all consecutive patients referred to the ICU of a single hospital who underwent at least two consecutive chest and/or abdominal contrast-enhanced CT scans within a time period of 30 days using DLIR and subsequently the FBP or IR algorithm (Advanced Modeled Iterative Reconstruction [ADMIRE] model-based algorithm or Adaptive Iterative Dose Reduction 3D [AIDR 3D] hybrid algorithm) for CT image reconstruction. The radiation ED, noise level, and signal-to-noise ratio (SNR) were compared between the different CT scanners. The non-parametric Wilcoxon test was used for statistical comparison. Statistical significance was set at p < 0.05. A total of 83 patients (mean age, 59 ± 15 years [standard deviation]; 56 men) were included. DLIR vs. FBP reduced the ED (18.45 ± 13.16 mSv vs. 22.06 ± 9.55 mSv, p < 0.05), while DLIR vs. FBP and vs. ADMIRE and AIDR 3D IR algorithms reduced image noise (8.45 ± 3.24 vs. 14.85 ± 2.73 vs. 14.77 ± 32.77 and 11.17 ± 32.77, p < 0.05) and increased the SNR (11.53 ± 9.28 vs. 3.99 ± 1.23 vs. 5.84 ± 2.74 and 3.58 ± 2.74, p < 0.05). CT scanners employing DLIR improved the SNR compared to CT scanners using FBP or IR algorithms in ICU patients despite maintaining a reduced ED.

Radiation Overuse in Intensive Care Units

Radiological imaging is essential for acute patient management in Intensive Care Units (ICUs); however, it introduces the risk of exposure to ionizing radiation. This review synthesizes research on radiation exposure in ICU settings, highlighting its rise during the COVID-19 pandemic and the rise in repetitive imaging. Our analysis extends to radiation safety thresholds, revealing that some ICU patients exceed the diagnostic reference level, emphasizing the need to balance diagnostic utility against potential long-term risks, such as cancer. Prospective studies have demonstrated an increase in the median cumulative effective dose in patients with trauma over time, prompting calls for improved awareness and monitoring. Moreover, innovative dose-reduction strategies and optimized protocols, especially in neuro-ICUs, promise to mitigate these risks. This review highlights the essential but risky role of radiological imaging in critical care. It advocates for rigorous radiation management protocols to safeguard patient health while ensuring the continuity of high-quality medical care.

Prognostic Value of the Radiographic Assessment of Lung Edema Score in Mechanically Ventilated ICU Patients

INTRODUCTION

The Radiographic Assessment of Lung Edema (RALE) score provides a semi-quantitative measure of pulmonary edema. In patients with acute respiratory distress syndrome (ARDS), the RALE score is associated with mortality. In mechanically ventilated patients in the intensive care unit (ICU) with respiratory failure not due to ARDS, a variable degree of lung edema is observed as well. We aimed to evaluate the prognostic value of RALE in mechanically ventilated ICU patients.

METHODS

Secondary analysis of patients enrolled in the 'Diagnosis of Acute Respiratory Distress Syndrome' (DARTS) project with an available chest X-ray (CXR) at baseline. Where present, additional CXRs at day 1 were analysed. The primary endpoint was 30-day mortality. Outcomes were also stratified for ARDS subgroups (no ARDS, non-COVID-ARDS and COVID-ARDS).

RESULTS

422 patients were included, of which 84 had an additional CXR the following day. Baseline RALE scores were not associated with 30-day mortality in the entire cohort (OR: 1.01, 95% CI: 0.98-1.03, p = 0.66), nor in subgroups of ARDS patients. Early changes in RALE score (baseline to day 1) were only associated with mortality in a subgroup of ARDS patients (OR: 1.21, 95% CI: 1.02-1.51, p = 0.04), after correcting for other known prognostic factors.

CONCLUSIONS

The prognostic value of the RALE score cannot be extended to mechanically ventilated ICU patients in general. Only in ARDS patients, early changes in RALE score were associated with mortality.

Imaging in the Intensive Care Unit

Radiology plays an important role in the management of the most seriously ill patients in the hospital. Over the years, continued advances in imaging technology have contributed to an improvement in patient care. However, even with such advances, the portable chest radiograph (CXR) remains one of the most commonly requested radiographic examinations. While they provide valuable information, CXRs remain relatively insensitive at revealing abnormalities and are often nonspecific. Chest computed tomography (CT) can display findings that are occult on CXR and is particularly useful at identifying and characterizing pleural effusions, detecting barotrauma including small pneumothoraces, distinguishing pneumonia from atelectasis, and revealing unsuspected or additional abnormalities which could result in increased morbidity and mortality if left untreated. CT pulmonary angiography is the modality of choice in the evaluation of pulmonary emboli which can complicate the hospital course of the ICU patient. This article will provide guidance for interpretation of CXR and thoracic CT images, discuss some of the invasive devices routinely used, and review the radiologic manifestations of common pathologic disease states encountered in ICU patients. In addition, imaging findings and complications of more specific clinical scenarios in which the incidence has increased in the ICU setting, such as patients who are immunocompromised, have interstitial lung disease, or COVID-19, will also be discussed. Communication between the radiologist and intensivist, particularly on complicated cases, is important to help increase diagnostic accuracy and leads to an improvement in the management of the most critically ill patients.

Exploring the Necessity of Routine Daily Chest X-rays for Mechanically Ventilated Patients in the Pediatric Intensive Care Unit: An Integrative Review

PROBLEM

In the PICU of a university teaching hospital, daily chest X-rays (CXR) are performed on all intubated and non-invasive ventilation-assisted patients, even when the patient is stable with no changes in clinical status. Inconsistent practice was identified with PICUs globally. This review aims to address the risk-benefit balance of clinical value, outcomes, cost, and radiation exposure when performing routine daily CXRs in the PICU.

ELIGIBILITY CRITERIA

CINAHL, Medline, and Embase (Ovid) were searched for relevant articles within the last ten years (2009 to 2019). Articles involving routine daily CXR on adult patients were included due to limited pediatric research.

SAMPLE

18 articles were included in this review which evaluated the necessity of routine daily CXR protocol in the ICU setting and the risks of radiation exposure (pediatric n = 5, adult n = 10, both n = 3).

RESULTS

When comparing the routine daily to on-demand CXR ordering protocols, there was no difference noted in clinical outcomes including mortality, complications, length of stay in hospital or ICU, and number of ventilator days. The on-demand CXR protocol decreased the number of CXRs per patient, which thereby decreased radiation exposure for patients, decreasing their risk of potential toxicity and malignancy.

CONCLUSION

Routine daily CXR protocols are no longer recommended due to lack of clinical value, similar outcomes, increased cost, and since it places patients at risk for undue radiation exposure.

IMPLICATIONS

Further studies should evaluate clinical and physical exam findings that would trigger ordering a CXR in order to optimize their diagnostic value in the pediatric setting.

Factors affecting high cumulative radiation exposure from paediatric computed tomography

Purpose

To estimate occurrence rate of high cumulative radiation exposure from paediatric computed tomography (CT), and to determine influential factors on high-dose inclination.

Material and methods

Patients below 18 years old receiving at least 50 mSv of a cumulative dose during a 5-year period in a tertiary care centre were retrospectively enrolled. Individual patient characteristics, diagnoses, frequency of exa-minations, scanner sites, designated scans, and effective doses were recorded. Collective doses were compared among groups of the diagnoses and scanner sites, and regression analyses were applied.

Results

Of 2771 patients, 3.2% received individual cumulative doses between 50 and 303 mSv (median, 74 mSv). Frequency of examinations ranged from 1 to 13 times (median, 4 times) per patient. About 70% of the patients had oncological illness. Radiation was predominantly high in a CT simulator that could contribute the percentage of collective dose to twice that of examinations owing to higher scanning parts and CT dose index. Some scanner sites used higher acquisition phases. Regression analysis showed that the number of scanning parts and phases significantly influenced the cumulative dose inclination (p < 0.05) while frequent examinations did not.

Conclusions

There was a low occurrence of paediatrics with high dose accumulation. Significant factors affecting potentially high exposure were customized CT protocols in the specific scanners.

Selective Computed Tomography (CT) Imaging is Superior to Liberal CT Imaging in the Hemodynamically Normal Pediatric Blunt Trauma Patient

BACKGROUND

The optimal imaging strategy in hemodynamically stable pediatric blunt trauma remains to be defined. The purpose of this study was to determine the differences between selective and liberal computed tomography (CT) strategy in a pediatric trauma population with respect to radiation exposure and outcomes.

METHODS

We performed a retrospective analysis of hemodynamically stable blunt pediatric trauma patients (≤16 y) who were admitted to a Level I trauma center between 2013-2016. Patients were stratified into selective and liberal imaging cohorts. Univariate and multivariate regression analyses were used to compare outcomes between the groups. Outcomes included radiation dose, hospital and ICU length of stay, complications and mortality.

RESULTS

Of the 485 patients included, 176 underwent liberal and 309 selective CT imaging. The liberal cohort were more likely to be severely injured (ISS>15: 34.1 versus 8.4%, P< 0.001). The odds of exposure to a radiation dose of >15 mSv were higher with liberal scanning in patients with both ISS > 15 (OR 2.78, 95% CI 1.76-5.19, P< 0.001) and ISS ≤ 15 (OR 3.41, 95% CI 2.19-8.44, P < 0.001). Adjusted outcomes regarding mortality, ICU length of stay, and complications were similar between the cohorts.

CONCLUSION

Selective CT imaging in hemodynamically stable blunt pediatric trauma patients was associated with reduced radiation exposure and similar outcomes when compared to a liberal CT strategy.

Cumulative radiation dose incurred during the management of complex pleural space infection

BACKGROUND

Complex pleural space infections are commonly managed with antibiotics, pleural drainage, intrapleural fibrinolytic therapy, and surgery. These strategies often utilize radiographic imaging during management, however little data is available on cumulative radiation exposure received during inpatient management. We aimed to identify the type and quantity of radiographic studies along with the resultant radiation exposure during the management of complex pleural space infections.

METHODS

Retrospective review of community network healthcare system from January 2015 to July 2018. Patients were identified through billing databases as receiving intrapleural fibrinolytic therapy and/or surgical intervention. Patient demographics, clinical outcomes, and inpatient radiographic imaging was collected to calculate cumulative effective dose.

RESULTS

A total of 566 patients were identified with 7275 total radiographic studies performed and a median cumulative effective dose of 16.9 (IQR 9.9-26.3) mSv. Multivariable linear regression analysis revealed computed tomography use was associated with increased cumulative dose, whereas increased age was associated with lower cumulative dose. Over 74% of patients received more than 10 mSv, with 7.4% receiving more than 40 mSv.

CONCLUSIONS

The number of radiographic studies and overall cumulative effective dose in patients hospitalized for complex pleural space infection was high with the median cumulative effective dose > 5 times normal yearly exposure. Ionizing radiation and modern radiology techniques have revolutionized medical care, but are likely not without risk. Additional study is warranted to identify the frequency and imaging type needed during complex pleural space infection management, attempting to keep ionizing radiation exposure as low as reasonably possible.

Strategies for dose reduction with specific clinical indications during computed tomography

Increasing integration of computed tomography (CT) into routine patient care has escalated concerns regarding associated radiation exposure. Specific patient cohorts, particularly those with cystic fibrosis (CF) and Crohn's disease, have repeat exposures and thus have an increased risk of high lifetime cumulative effective dose exposures. Thoracic CT is the gold standard imaging method in the diagnosis, assessment and management of pulmonary disease. In the setting of CF, CT demonstrates increased sensitivity compared with pulmonary function tests and chest radiography. Furthermore, in specific cases of Crohn's disease, CT demonstrates diagnostic superiority over magnetic resonance imaging (MRI) for radiological evaluation. Low dose CT protocols have proven beneficial in the evaluation of CF, Crohn's disease and renal calculi, and in the follow up of testicular cancer patients. For individuals with chronic conditions warranting frequent radiological follow up, the focus must continue to be the incorporation of appropriate CT use into patient care. This is of particular importance for the paediatric population who are most susceptible to potential radiation induced malignancy. CT technological developments continue to focus on radiation dose optimisation. This article aims to highlight these advancements, which prioritise the acquisition of diagnostically satisfactory images with the least amount of radiation possible.

Demonstrating the Use of Optical Fibres in Biomedical Sensing: A Collaborative Approach for Engagement and Education

This paper demonstrates how research at the intersection of physics, engineering, biology and medicine can be presented in an interactive and educational way to a non-scientific audience. Interdisciplinary research with a focus on prevalent diseases provides a relatable context that can be used to engage with the public. Respiratory diseases are significant contributors to avoidable morbidity and mortality and have a growing social and economic impact. With the aim of improving lung disease understanding, new techniques in fibre-based optical endomicroscopy have been recently developed. Here, we present a novel engagement activity that resembles a bench-to-bedside pathway. The activity comprises an inexpensive educational tool (<$70) adapted from a clinical optical endomicroscopy system and tutorials that cover state-of-the-art research. The activity was co-created by high school science teachers and researchers in a collaborative way that can be implemented into any engagement development process.

Radiation Exposure in Pediatric Intensive Care Unit Patients: How Much Is Too Much?

We aimed to determine median cumulative radiation exposure in pediatric intensive care unit (PICU) patients, proportion of patients with high radiation exposure (above annual average radiation per person of 6.2 mSv), and determine risk factors for high exposure. This was a retrospective chart review of PICU patients up to 18 years of age admitted to a large community hospital over 2 years. Radiologic studies and radiation exposure were determined for each patient, and total hospital radiation exposure was classified as high (>6.2 mSv) or not (≤6.2 mSv). Median radiation exposure per patient was 0.2 mSv (interquartile range = 2.1) and 11.7% of patients received >6.2 mSv radiation during their hospitalization. Factors associated with high radiation exposure included admission for trauma or surgery, number of computed tomography scans, age, and PICU length of stay (all P < .0001). We concluded that subsets of PICU patients are at risk of high radiation exposure. Policies and protocols may help minimize radiation exposure among PICU patients.

Trends in Use of Daily Chest Radiographs Among US Adults Receiving Mechanical Ventilation

IMPORTANCE

Guidelines from December 2011 recommended against obtaining daily chest radiographs (CXRs) for patients requiring mechanical ventilation (MV). Daily CXR use for patients receiving MV in US hospitals is unknown and, if high, may represent an opportunity to reduce low-value care and unnecessary radiation.

OBJECTIVES

To determine frequency of daily CXR use for US patients receiving MV, assess variability across hospitals, and evaluate whether use has decreased over time.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective cohort study of hospitalized adults (aged ≥18 years) receiving MV for 3 days or longer. Mechanical ventilation was defined by having an International Classification of Diseases, Ninth Revision, Clinical Modification code of 96.7x and an MV charge on more than 1 hospital day. Hospital discharges in the Premier Perspectives database were examined from July 1, 2008, to December 31, 2014. Data analysis was conducted from July 28, 2017, to December 13, 2017.

EXPOSURES

Hospital discharge date (quarter of the year) and hospital in which patients received MV.

MAIN OUTCOMES AND MEASURES

The outcome was daily CXR use (up to 7 days) during MV. We used standard statistics to describe CXR use, multilevel multivariable regression modeling with adjusted median odds ratio (OR) to evaluate variability by hospital, and multivariable piecewise regression (breakpoint: fourth quarter of 2011) with adjusted OR to evaluate time trends and response to guideline recommendations.

RESULTS

The primary cohort included 512 518 patients receiving MV (mean [SD] age, 63.0 [16.1] years; 46% female) in 416 hospitals, of whom 321 093 (63%) received daily CXRs. Wide variability was seen across hospitals; hospitals performed daily CXRs on a median of 66% of patients (interquartile range, 50%-77%; full range, 12%-97%). The adjusted median OR was 2.43 (95% CI, 2.29-2.59), suggesting the same patient had 2.43-fold higher odds of receiving a daily CXR if admitted to a higher- vs lower-use hospital; the odds of receiving daily CXRs were unchanged through quarter 3 of 2011 (adjusted OR, 1.00; 95% CI, 0.99-1.01), after which there was a 3% relative reduction in the odds of daily CXR use per quarter (adjusted OR, 0.97; 95% CI, 0.96-0.98).

CONCLUSIONS AND RELEVANCE

Three-fifths of US patients receiving MV also received daily CXRs from 2008 to 2014, although use declined slowly after new guidelines were published. The hospital at which a patient received care was associated with the odds of daily CXR receipt.