Mean Effective Radiation Dose Research Articles

CT-based migration analysis of a tibial component compared to radiostereometric analysis : one-year results of a prospective single-group implant safety study.

Radiostereometric analysis (RSA) is considered the gold standard for in vivo migration analysis, but CT-based alternatives show comparable results in the shoulder and hip. We have previously validated a CT-based migration analysis method (CTMA) in a knee phantom compared to RSA. In this study, we validated the method in patients undergoing total knee arthroplasty (TKA). Our primary outcome measure was the difference in maximum total point motion (MTPM) between the differing methods. A total of 31 patients were prospectively studied having undergone an uncemented medial pivot knee TKA. Migrations were measured up to 12 months with marker-based and model-based RSA, and CT-RSA. Mean precision data for MTPM were 0.27 mm (SD 0.09) for marker-based RSA, 0.37 mm (SD 0.26) for model-based RSA, and 0.25 mm (SD 0.11) for CTMA. CTMA was as precise as both RSA methods (p = 0.845 and p = 0.156). At three months, MTPM showed a mean of 0.66 mm (95% CI 0.52 to 0.81) for marker-based RSA, 0.79 (95% CI 0.64 to 0.94) for model-based RSA, and 0.59 (95% CI 0.47 to 0.72) for CTMA. There was no difference between CTMA and marker-based RSA (p = 0.400), but CTMA showed lower migration than model-based RSA (p = 0.019). At 12 months, MTPM was 1.03 (95% CI 0.79 to 1.26) for marker-based RSA, 1.02 (95% CI 0.79 to 1.25) for model-based RSA, and 0.71 (95% CI 0.48 to 0.94) for CTMA. MTPM for CTMA was lower than both RSA methods (p < 0.001). Differences between migration increased between the methods from three to 12 months. Mean effective radiation doses per examination were 0.016 mSv (RSA) and 0.069 mSv (CT). Imaging time for performing RSA radiographs was 17 minutes 26 seconds (SD 7 mins 9 sec) and 4 minutes 24 seconds (SD 2 mins 3 sec) for CT. No difference in precision was found between CTMA and marker- or model-based RSA, but CTMA shows lower migration values of the tibial component at 12 months. CTMA can be used with low effective radiation doses, and CT image acquisition is faster to perform than RSA methods and may be suitable for use in ordinary clinical settings.

Evaluating Lung Changes in Long COVID: Ultra-Low-Dose vs. Standard-Dose CT Chest.

Frequent chest CTs within a short period during follow-up of long COVID patients may increase the risk of radiation-related health effects in the exposed individuals. We aimed to assess the image quality and diagnostic accuracy of ultra-low-dose CT (ULDCT) chest compared to standard-dose CT (SDCT) in detecting lung abnormalities associated with long COVID. In this prospective study, 100 long COVID patients with respiratory dysfunction underwent SDCT and ULDCT chest that were compared in terms of objective (signal-to-noise ratio, SNR) and subjective image quality (image graininess, sharpness, artifacts, and diagnostic accuracy along with the European guidelines on image quality criteria for CT chest), detection of imaging patterns of long COVID, CT severity score, and effective radiation dose. Additionally, the diagnostic performance of ULDCT was compared among obese (BMI≥30kg/m2) and non-obese (BMI<30kg/m2) subjects. The mean age of study participants was 53 ± 12.9years, and 68% were male. The mean SNR was 31.4 ± 5.5 and 11.3 ± 4.6 for SDCT and ULDCT respectively (p< 0.0001). Common findings seen on SDCT included ground-glass opacities (GGOs, 77%), septal thickening/reticulations (67%), atelectatic/parenchymal bands (63%) and nodules (26%). ULDCT provided sharp images, with no/minimal graininess, and high diagnostic confidence in 81%, 82% and 80% of the cases respectively. The sensitivity of ULDCT for various patterns of long COVID was 72.7% (GGOs), 71.6% (interlobular septal thickening/reticulations), 100% (consolidation), 81% (atelectatic/parenchymal bands) and 76.9% (nodules). ULDCT scans in non-obese subjects exhibited a significantly higher sensitivity (88% vs. 60.3%, p < 0.0001) and diagnostic accuracy (97.7% vs. 84.9%, p < 0.0001) compared to obese subjects. ULDCT showed very strong correlation with SDCT in terms of CT severity score (r = 0.996, p < 0.0001). The mean effective radiation dose with ULDCT was 0.25 ± 0.02mSv with net radiation dose reduction of 94.8% ± 1.7% (p < 0.0001) when compared to SDCT (5.5 ± 1.96mSv). ULDCT scans achieved comparable diagnostic accuracy to SDCT for detecting long COVID lung abnormalities in non-obese patients, while significantly reducing radiation exposure.

“Can computed tomographic angiography” solve the puzzle of complexities in the pediatric complex congenital heart disease’s

ABSTRACT Background: Accurate evaluation of cardiac and extracardiac anomalies in complex congenital heart diseases (CHDs) is vital for diagnosis and management. Trans-thoracic echocardiography (TTE) is generally accepted as the primary imaging technique for the evaluation of CHD; however being operator-dependent and acoustic window limitations, there can be significant hindrances in better evaluation and depiction of cardiac and extracardiac malformations. Computed tomographic angiography (CTA) has been proven to be a competent noninvasive diagnostic modality in the delineation of both cardiac and extracardiac malformations with high accuracy and effectivity. The aims and objectives were to evaluate the role of CTA in the diagnosis and assessment of cardiovascular and relevant extracardiac systemic malformation in cases of complex CHD and its comparison to transthoracic echocardiography, with subsequent calculation of average effective radiation dose for each individual case. The purpose of the study was to ascertain the role of Cardiac CTA in unraveling these twists and turns, and to know whether additional radiation dose is justified in the evaluation of associated extracardiac systemic anomalies. Materials and Methods: Fifty patients with complex CHD were included in the study, who underwent TTE and nongated CTA over the period of 2 years. CTA and TTE findings were recorded and compared with the Surgical and Cardiac catheter angiographic findings, which were taken as the gold standard. Scans were also evaluated for relevant extracardiac systemic abnormalities, and effective radiation dose was calculated for each scan. Results: Fifty patients with male-to-female ratio of 29:21 and a mean age of 2.7 years. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy for diagnosing CHD were 95.83%, 100%, 100%, 99.35%, and 99.44% for CTA and 76.96%, 99.78%, 98.24%, 96.51%, and 96.69% for TTE respectively. We found that CTA has more sensitivity, specificity, NPV, PPV, and diagnostic accuracy than TTE, not only in intracardiac but also in extracardiac and systemic malformations. The total mean effective radiation dose calculated was 0.85 ± 0.19 mSv.mGy−1.cm−1 and is compared with previous comparable studies. Effective radiation dose was significantly reduced by employing low radiation protocols. The additional findings detected on CTA in a significant proportion of patients had changed the operative course for surgeons. Conclusions: CTA has important clinical value in the diagnosis and management of complex CHD, complementing and extending the findings of TTE. Hence, it is vital as part of an adequate preoperative assessment algorithm in cases of complex CHD and can’t be replaced by TTE. However, radiation dose remains a limiting factor, this can be overcome to some extent by employing low radiation dose protocols.

QUANTIFYING RADIATION EXPOSURE IN THE RADIOLOGICAL INVESTIGATION OF NON-ARTHRITIC HIP PAIN

Radiological investigations are essential in the work-up of patients presenting with non-arthritic hip pain, to allow close review of the complex anatomy around the hip and proximal femur. The aim of this study is to quantify the radiation exposure associated with common radiological investigations performed in assessing young adult patients presenting with non-arthritic hip pain.A retrospective review of our UK tertiary hip preservation centre institutional imaging database was performed. Data was obtained for antero-posterior, cross-table lateral and frog-lateral radiographs, along with data for the low dose CT hip protocol and the Mako CT Hip protocol. The radiation dose of each imaging technique was measured in terms of dose-area product (DAP) with units of mGycm2, and the effective doses (ED, mSv) calculated.The mean effective radiation dose for hip radiographs was in the range 0.03 to 0.83mSv (mean DLP 126.7–156.2 mGycm2). The mean effective dose associated with the low-dose CT hip protocol was 3.04mSv (416.8 mGycm2) and for the Stryker Mako CT Hip protocol was 8.4mSv (1061 mGycm2). The radiation dose associated with use of CT imaging was significantly greater than plain radiographs (p&lt;0.005)Investigation of non-arthritic hip pain can lead to significant ionising radiation exposure for patients. In our institution, the routine protocol is to obtain an anteroposterior radiograph and then a specific hip sequence 3 Tesla MRI including anteversion views. This provides the necessary information in the majority of cases, with CT scanning reserved for more complex cases where we feel there is a specific indication. We would encourage the hip preservation community to carefully consider and review the use of ionising radiation investigations.

Ultralow-Dose Dynamic Expiratory CT and Repeated Imaging Enhance Evaluation for Tracheomalacia.

This study aims to determine if a novel imaging protocol (ultralow-dose dynamic expiratory computed tomography [CT] with repeated imaging) identifies tracheomalacia (TM) more reliably than traditional dynamic tracheal CT. We performed a retrospective evaluation of 184 consecutive ultralow-dose dynamic CTs for TM during 2017. The protocol obtains images during 1 inspiration and 2 forced expirations. Tracheal narrowing during both expirations (airway narrowing [percentage] during first dynamic expiration CT [DE1], airway narrowing [percentage] during second dynamic expiration CT [DE2]) was reported as a percentage of inspiratory area. We identified maximum narrowing of each patient's sequence (maximum narrowing [percentage] on either dynamic expiration CT [DEmax] = greatest narrowing of DE1 or DE2) and compared DE1, DE2, and DEmax in individual studies and between patients. Outcomes included frequency of TM, tracheal narrowing, and severity. Reliability was assessed by comparing tracheal area narrowing and TM grade. There was significantly more airway narrowing using 2 expiratory image acquisitions. Average DEmax tracheal area was 12% narrower than DE1 alone and 21% worse than DE2 alone (both P < 0.001). Using DEmax, TM was diagnosed 35% more often than DE1 alone and 31% more often than DE2 alone ( P < 0.001). DEmax identified more severe distribution of TM compared with DE1 or DE2 alone ( P < 0.001). Reliability between DE1 and DE2 was good for tracheal narrowing and moderate for TM grade. The mean effective radiation dose was 2.41 millisievert (mSv) for routine inspiration CT and 0.07 mSv for each dynamic expiration CT (total effective radiation, 2.55 mSv). Dynamic expiration CT with 2 expiratory image acquisitions enhanced evaluation of TM, minimally increased radiation dose, and should be considered as a noninvasive screening option.

Dynamic airway computed tomography and flexible bronchoscopy for diagnosis of tracheomalacia in children: A comparison study.

Tracheomalacia (TM) is an important cause of respiratory morbidity. Dynamic flexible bronchoscopy is considered the gold standard for diagnosis. Dynamic airway computed tomography (DACT) is a low radiation, noninvasive diagnostic tool utilizing images obtained continuously over several respiratory cycles. We aimed to assess the accuracy of DACT in TM diagnosis. Retrospective analysis of all patients who underwent both DACT and flexible bronchoscopy within 6 months. Airway anterior-posterior (AP) diameter was measured on multiplanar reconstructions CT in both the inspiratory and expiratory phases. Using still images from the bronchoscopy videos, the AP diameter of the trachea was measured at points of maximal and minimal diameter during tidal breathing. Degree of TM on both DACT and flexible bronchoscopy were graded using a scaling system of 50%-74%, 75%-89%, and 90%-100% as described by the European Respiratory Society. Twenty-four patients met inclusion criteria with an average time of 19.5 days between CT and bronchoscopy. The specificity and sensitivity of DACT for the overall diagnosis of TM was 100% and 68%, respectively, with a positive predictive value of 100% and a negative predictive value of 62%. There was a strong positive correlation between DACT and flexible bronchoscopy in the measurement of tracheal AP diameter changes (ρ = 0.773, R2 0.597, p = 0.00001). Mean effective radiation dose for DACT was 0.1 mSv. Ultralow dose DACT has excellent specificity and positive predictive value for both detection of TM and categorizing severity of tracheal collapse but is not sufficiently sensitive to rule it out.

Percutaneous cryoablation of renal tumours under computed tomography guidance: methodology of the procedure.

The incidence of renal cell carcinoma has been steadily increasing over the past two decades, raising the need for minimally invasive approaches. We sought to present the methodology of the percutaneous cryoablation (PCA) procedure developed based on one year of experience with 81 PCA procedures. The percutaneous cryoablation programme at Wroclaw Medical University Hospital has been successfully operating for a year. During this period, patients who were ineligible for partial nephrectomy either because of numerous comorbidities or strong preference against surgery were treated with PCA. Each procedure was conducted with the close cooperation of an interventional radiologist and a urologist. Over the past year, 81 procedures in 74 individuals have been performed and thoroughly analysed. The mean and median effective radiation doses were 12.57 mSv and 10.76 mSv, respectively. Comprehensive details of our workflow are described within the body of the manuscript. Percutaneous cryoablation is a technically effective treatment approach for carefully selected individuals with small renal masses. However, starting a PCA programme from scratch necessitates creation of detailed protocols, as well as close interventional radiologist and urologist cooperation. This review outlines the established workflow and shares insights gained from one year of experience with percutaneous cryoablation.

Intraprocedural, Intra-Arterial CT Foot Perfusion Examination for Assessment of Endovascular Therapy in Patients With Critical Limb Ischemia: A Prospective Pilot Study.

Current techniques to evaluate computed tomography (CT) foot perfusion in patients with critical limb ischemia use high contrast doses and cannot be used during endovascular procedures. CT perfusion of the foot with intra-arterial contrast injection during endovascular treatment in a hybrid angiography CT suite might solve these problems. The main objective of this study was to evaluate whether intra-arterial CT foot perfusion using a hybrid CT angiosystem is feasible during endovascular treatment for critical limb ischemia. This prospective pilot study investigated intraprocedural, intra-arterial CT perfusion of the foot using a hybrid CT angiosystem in 12 patients before and after endovascular treatment for critical limb ischemia. Time to peak (TTP) and arterial blood flow were measured before and after treatment and compared using a paired t test. All 24 CT perfusion maps could be calculated adequately. The contrast volume used for one perfusion CT scan was 4.8 ml. The mean TTP before treatment was 12.8 seconds (standard deviation [SD] 2.8) and the mean TTP posttreatment was 8.4 seconds (SD 1.7), this difference being statistically significant (p=.001). Tendency toward increased blood flow after treatment, 340 ml/min/100 ml (SD 174) vs 514 ml/min/100 ml (SD 366) was noticed (p=.104). The mean effective radiation dose was 0.145 mSv per scan. Computed tomography perfusion of the foot with low contrast dose intra-arterial contrast injection during endovascular treatment in a hybrid angiography CT suite is a feasible technique. Intra-arterial CT foot perfusion using a hybrid CT-angiography system is a feasible new technique during endovascular therapy for critical limb ischemia to assess the results of the treament. Future research is necessary in defining endpoints of endovascular treatment and establishing its role in limb salvage prognostication.

Image Quality Improvement of Low-dose Abdominal CT using Deep Learning Image Reconstruction Compared with the Second Generation Iterative Reconstruction

Whether deep learning-based CT reconstruction could improve lesion conspicuity on abdominal CT when the radiation dose is reduced is controversial. To determine whether DLIR can provide better image quality and reduce radiation dose in contrast-enhanced abdominal CT compared with the second generation of adaptive statistical iterative reconstruction (ASiR-V). This study aims to determine whether deep-learning image reconstruction (DLIR) can improve image quality. In this retrospective study, a total of 102 patients were included, who underwent abdominal CT using a DLIR-equipped 256-row scanner and routine CT of the same protocol on the same vendor's 64-row scanner within four months. The CT data from the 256-row scanner were reconstructed into ASiR-V with three blending levels (AV30, AV60, and AV100), and DLIR images with three strength levels (DLIR-L, DLIR-M, and DLIR-H). The routine CT data were reconstructed into AV30, AV60, and AV100. The contrast-to-noise ratio (CNR) of the liver, overall image quality, subjective noise, lesion conspicuity, and plasticity in the portal venous phase (PVP) of ASiR-V from both scanners and DLIR were compared. The mean effective radiation dose of PVP of the 256-row scanner was significantly lower than that of the routine CT (6.3±2.0 mSv vs. 2.4±0.6 mSv; p< 0.001). The mean CNR, image quality, subjective noise, and lesion conspicuity of ASiR-V images of the 256-row scanner were significantly lower than those of ASiR-V images at the same blending factor of routine CT, but significantly improved with DLIR algorithms. DLIR-H showed higher CNR, better image quality, and subjective noise than AV30 from routine CT, whereas plasticity was significantly better for AV30. DLIR can be used for improving image quality and reducing radiation dose in abdominal CT, compared with ASIR-V.

Diagnostic Value of Computed Tomography Angiography in Suspected Acute Ischemic Stroke Patients With Respect to National Institutes of Health Stroke Scale Score.

Noncontrast computed tomography (NCCT) plus computed tomography angiography (CTA) is the standard imaging modality for acute stroke. We investigated whether there is an additional diagnostic value of supra-aortic CTA in relation to National Institutes of Health Stroke Scale (NIHSS) and resultant effective radiation dose. In this observational study, 788 patients with suspected acute stroke were included and divided into 3 NIHSS groups: group 1, NIHSS 0-2; group 2, NIHSS 3-5; and group 3, NIHSS ≥ 6.Computed tomography scans were assessed for findings of acute ischemic stroke and vascular pathologies in 3 regions. Final diagnosis was obtained from medical records. Effective radiation dose was calculated based on the dose-length product. Seven hundred forty-one patients were included. Group 1 had 484 patients, group 2 had 127 patients, and group 3 had 130 patients. Computed tomography diagnosis of acute ischemic stroke was made in 76 patients. In 37 patients, a diagnosis of acute stroke was made based on pathologic CTA findings in case of an unremarkable NCCT. Stroke occurrence was the lowest in groups 1 and 2, with 3.6% and 6.3%, respectively, compared with 12.7% in group 3. If both NCCT and CTA were positive, the patient was discharged with a stroke diagnosis. Male sex had the highest effect on the final stroke diagnosis. The mean effective radiation dose was 2.6 mSv. In female patients with NIHSS 0-2, additional CTA rarely contains relevant additional findings decisive for treatment decisions or overall patient outcomes; therefore, CTA in this patient group might yield less impactful findings, and the applied radiation dose could be lowered by approximately 35%.

Photon-counting versus Dual-Source CT of Congenital Heart Defects in Neonates and Infants: Initial Experience.

Background Photon-counting CT (PCCT) has been shown to improve cardiovascular CT imaging in adults. Data in neonates, infants, and young children under the age of 3 years are missing. Purpose To compare image quality and radiation dose of ultrahigh-pitch PCCT with that of ultrahigh-pitch dual-source CT (DSCT) in children suspected of having congenital heart defects. Materials and Methods This is a prospective analysis of existing clinical CT studies in children suspected of having congenital heart defects who underwent contrast-enhanced PCCT or DSCT in the heart and thoracic aorta between January 2019 and October 2022. CT dose index and dose-length product were used to calculate effective radiation dose. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated by standardized region-of-interest analysis. SNR and CNR dose ratios were calculated. Visual image quality was assessed by four independent readers on a five-point scale: 5, excellent or absent; 4, good or minimal; 3, moderate; 2, limited or substantial; and 1, poor or massive. Results Contrast-enhanced PCCT (n = 30) or DSCT (n = 84) was performed in 113 children (55 female and 58 male participants; median age, 66 days [IQR, 15-270]; median height, 56 cm [IQR, 52-67]; and median weight, 4.5 kg [IQR, 3.4-7.1]). A diagnostic image quality score of at least 3 was obtained in 29 of 30 (97%) with PCCT versus 65 of 84 (77%) with DSCT. Mean overall image quality ratings were higher for PCCT versus DSCT (4.17 vs 3.16, respectively; P < .001). SNR and CNR were higher for PCCT versus DSCT with SNR (46.3 ± 16.3 vs 29.9 ± 15.3, respectively; P = .007) and CNR (62.0 ± 50.3 vs 37.2 ± 20.8, respectively; P = .001). Mean effective radiation doses were similar for PCCT and DSCT (0.50 mSv vs 0.52 mSv; P = .47). Conclusion At a similar radiation dose, PCCT offers a higher SNR and CNR and thus better cardiovascular imaging quality than DSCT in children suspected of having cardiac heart defects. © RSNA, 2023.

Ventriculoperitoneal shunt survey in pediatric patients in an emergency setting: a comparison between ultra-low-dose CT using a tin filter and plain radiography.

The aim of this study was to investigate the diagnostic performance, effective radiation dose, and examination time of ventriculoperitoneal shunt evaluation using full-body ultra-low-dose CT (ULD CT) with a tin filter compared with digital plain radiography in a pediatric population. A retrospective cross-sectional study was conducted in an emergency setting. Data from 143 children were collected. Sixty were examined with ULD CT with a tin filter and 83 with digital plain radiography methods. Effective doses and times were compared between the two methods. Two observers in pediatric radiology evaluated the patient images. Clinical findings and results from shunt revision, if it was performed, were used to evaluate the diagnostic performance between modalities. An examination-room simulation was performed of the two methods to estimate representative examination times. The mean effective radiation dose for ULD CT with the tin filter was estimated to be 0.29 ± 0.16 mSv compared with 0.16 ± 0.19 mSv for digital plain radiography, with both examinations associated with a very low lifetime attributable risk (< 0.01%). The shunt tip could be more reliably located with ULD CT. ULD CT also allowed assessment of additional findings to explain patient symptoms, such as a cyst at the tip of the shunt catheter and the presence of an obstructing rubber nipple in the duodenum that could not have been observed on a plain radiograph. The examination time with ULD CT of the shunt was estimated to be 20 minutes. The examination time of the shunt with digital plain radiography, including the examination itself time and transfer of the patient between rooms, was estimated to be 60 minutes. ULD CT using a tin filter allows good visualization of the position or disruption of the shunt catheter that is comparable or superior to plain radiography, at a higher dose, while providing additional findings and reduced patient discomfort.

CT-based migration analysis is more precise than radiostereometric analysis for tibial implants: a phantom study on a porcine cadaver.

Radiostereometric analysis (RSA) is the gold standard for migration analysis, but computed tomography analysis methods (CTRSA) have shown comparable results in other joints. We attempted to validate precision for CT compared with RSA for a tibial implant. RSA and CT were performed on a porcine knee with a tibial implant. Marker-based RSA, model-based RSA (MBRSA), and CT scans from 2 different manufacturers were compared. CT analysis was performed by 2 raters for reliability evaluation. 21 double examinations for precision measurements for RSA and CT-based Micromotion Analysis (CTMA) were analysed. Mean (95% confidence interval) precision data for maximum total point motion (MTPM) using marker-based RSA was 0.45 (0.19-0.70) and 0.58 (0.20-0.96) using MBRSA (F-statistic 0.44 [95% CI 0.18-1.1], p = 0.07). Precision data for total translation (TT) for CTMA was 0.08 (0.03-0.12) for the GE scanner and 0.11 (0.04-0.19) for the Siemens scanner (F-statistic 0.37 [0.15-0.91], p = 0.03). When comparing the aforementioned precision for both RSA methods with both CTMA analyses, CTMA was more precise (p < 0.001). The same pattern was seen for other translations and migrations. Mean effective radiation doses were 0.005 mSv (RSA) (0.0048-0.0050) and 0.08 mSv (CT) (0.078-0.080) (p < 0.001). Intra- and interrater reliability were 0.79 (0.75-0.82) and 0.77 (0.72-0.82), respectively. CTMA is more precise than RSA for migration analysis of a tibial implant, has overall good intra- and interrater reliability but higher effective radiation doses in a porcine cadaver.

Prone Dynamic CT Myelography in Spontaneous Intracranial Hypotension : Diagnostic Need and Radiation Doses.

The diagnostic work-up in patients with spontaneous intracranial hypotension (SIH) and spinal longitudinal extradural CSF collection (SLEC) on magnetic resonance imaging (MRI) comprises dynamic digital subtraction myelography (dDSM) in prone position for leak detection. Dynamic computed tomography (CT) myelography (dCT-M) in prone position follows if the leak is not unequivocally located. A drawback of dCT‑M is ahigh radiation dose. This study evaluates the diagnostic needs of dCT-M examinations and measures to reduce radiation doses. Frequency, leak sites, length and number of spiral acquisitions, DLP and effective doses of dCT‑M were retrospectively recorded in patients with ventral dural tears. Of 42patients with ventral dural tears, 8 underwent 11dCT‑M when the leak was not unequivocally shown on digital subtraction myelography. The median number of spiral acquisitions was 4 (range 3-7) and the mean effective radiation dose 30.6 mSv (range 13.1-62.16 mSv) mSv. Five of eight leaks were located in the upper thoracic spine (range C7/Th1-Th2/3). Bolus tracking of intrathecal contrast agent in dCT‑M was used to limit the number and length of spiral acquisitions. A dCT‑M in prone position to localize aventral dural tear is needed in every fifth patient with aSLEC on MRI. It is typically needed when the leak is located in the upper thoracic spine and when patients have broad shoulders. Measures to reduce the radiation dose include bolus tracking or to repeat the DSM with adjusted positioning of patient.

The Role of Triple Rule-out CT in an Indian Emergency Setting.

Emergency physicians are acutely aware of the consequences of missing fatal diagnoses for acute non-traumatic chest pain and subjecting patients to over-testing. In the large arsenal of tests that are available to us, a triple rule-out computed tomography (TRO-CT) Angiography is often less pursued, due to concerns about their efficacy and safety or because of nescience. We aim to find the yield of the test in an Indian emergency setting and impart some knowledge about it along the way. Twenty-six patients who presented to the emergency department of our institute with acute chest pain, with non-specific electrocardiogram (ECG) findings and negative serial troponin I, underwent TRO-CT. HEART scores of all patients, calculated at their presentation, were correlated with TRO-CT findings. Triple rule-out computed tomography angiography was positive in 5 patients (20%), of which 4 cases (16%) were diagnosed to have significant coronary artery disease and one had an acute pulmonary embolism. All 4 patients who had significant coronary artery disease (CAD) diagnosed by TRO-CT had a HEART score of intermediate risk. The mean effective radiation dose of the entire TRO study was 19.024 ± 3.319 mSv (range = 13.89-25.95 mSv). Triple rule-out CT angiography is a useful tool in the evaluation of patients presenting with acute chest pain in the emergency and can be an important adjunct in ruling out significant CAD in intermediate-risk patients. Emergency physicians and young residents need to know about this tool in their armamentarium to tackle doubtful cases. Pattereth N, Chaliyadan S, Mathew R, Kumar S, Das CJ, Aggarwal P. et al. The Role of Triple Rule-out CT in an Indian Emergency Setting. Indian J Crit Care Med 2023;27(3):190-194.

Dual versus single energy cardiac CT to measure extracellular volume in cardiac amyloidosis: correlations with cardiac MRI

Determine in cardiac amyloid (CA) patients, whether cardiac CT derived extracellular volume (ECV) correlates with that obtained by MRI. Perform this correlation with single (SECT) versus dual energy (DECT) CT and evaluate whether a single sample volume ECV-measure was as reliable as a global (16 segment) assessment. CA patients who had undergone a clinical cardiac MRI (CMR) were recruited prospectively. SECT and DECT cardiac scans were performed. Three ECG-triggered prospective SECT scans were acquired: non-contrast, arterial-phase contrast and 5-minute delayed images. A DECT scan was performed at 7min. Post processing was used to determine ECV. Analyses of SECT or DECT global ECV versus CMR were performed using the Pearson correlation coefficient, Bland Altman analysis and Intraclass correlation coefficient (ICC). Similar analyses were performed to examine the performance of single-segment sampling by SECT or DECT versus CMR. 25 patients were recruited, mean age was 80.0±7.1years, 80% were male, 21 patients had transthyretin- CA, 4 had light chain- CA. Correlations were close with both SECT or DECT global ECV versus CMR (r=0.79 and 0.88 respectively, p<0.001 for both). Reliability of both SECT and DECT to assess global ECV in comparison to CMR was good: ICC for SECT was 0.88 (95% CI 0.73-0.95) and 0.93 (95% CI 0.82-0.97) for DECT. For single volume sampling techniques: correlations were close with both SECT or DECT versus CMR (r=0.60 and 0.72 respectively, p<0.01 for both) There was no difference in ICC for SECT (0.74, 95%CI 0.41-0.88) versus DECT (0.84, 95% CI 0.63-0.93). Wider confidence intervals were noted for ICC with single versus global CT derived ECV assessment. Mean effective radiation dose was for SECT was 5.49±8.04mSv and 6.90±3.01mSv for DECT dual energy CT (p=0.75). Global ECV values derived by both DECT or SECT correlated with those obtained by CMR and demonstrated good reliability by ICC in a population of CA patients. DECT and SECT single sampling derived ECV values also demonstrated close correlation and good reliability but the ICCs for single sampling had wider confidence intervals than global ECV assessment.

Microsievert Wide-Volume Versus Spiral Computed Tomography Using an Automatic Exposure Control System in the Diagnosis of Foreign Body Aspiration in Children.

Foreign body aspiration (FBA) in childhood is a life-threatening condition that necessitates prompt management to prevent devastating complications. Different imaging methods are used in the diagnosis of FBA. The aim of this study was to compare the diagnostic value and dose of microsievert wide-volume computed tomography (μSv-WV-CT) with multidetector computed tomography using an automatic exposure control system (MDCT-AEC) in children with FBA. In this single-center cross-sectional study, 102 cases diagnosed with FBA between September 2013 and September 2021 were retrospectively evaluated. The patients were divided into 2 groups according to the diagnostic modality used: group A, μSv-WV-CT (2016-2021) and group B, MDCT-AEC (2013-2021). The diagnostic performance and radiation dose of the 2 groups were statistically compared. The diagnostic performance (sensitivity, specificity, positive predictive value, negative predictive value, and accuracy) of the 2 groups was similar. The mean effective radiation dose of group A was 34.89 ± 0.01 μSv, which was significantly lower than that of group B (179.75 ± 114.88 μSv) ( P < 0.001). In children with suspected FBA, μSv-WV-CT at a lower radiation dose had similar diagnostic performance to MDCT-AEC.

DIAGNOSTIC ACCURACY AND COMPLICATIONS OF PERCUTANEOUS CT-GUIDED NEEDLE BIOPSY OF LUNG NODULES IN 161 PATIENTS

Objective: Transthoracic needle biopsy is a diagnostic method that has proven its reliability in lung nodules and is frequently applied in daily practice. The diagnostic accuracy of biopsies performed with computed tomography navigation is quite high, even if the lesion sizes are smaller than 1 cm. We aimed to evaluate the diagnostic accuracy and complications of the computed tomography-guided percutaneous transthoracic needle biopsy procedure performed in our center.&#x0D; Material and Methods: Patients who underwent computed tomography guided percutaneous transthoracic pulmonary nodule biopsy procedure between January 2017 and January 2020 were included in the study. The size and anatomic location of lesions, the distance between the pleura and the lesion, the angle of the needle with the pleura, the procedure time, the number of pathologic samples taken per patient, the total radiation dose, complications, and the pathological results of the lesions were analyzed from the patients’ computed tomography images and patients’ records.&#x0D; Results: Among the 161 patients admitted for the transthoracic percutaneous needle biopsy procedure, 135 were male (mean age 64.3±11.1 years) and 26 were females (mean age 61.3±15.4 years). The pathological evaluation of 32 patients were reported as non-diagnostic. The diagnostic accuracy of computed tomography guided transthoracic biopsy was calculated as 80.1%. Major complications occurred in 10 patients (6.2%), and minor complications occurred in 60 patients (37.2%). The rate of procedure requiring chest tube insertion was 4.9%. The mean effective radiation dose of the patients per procedure was calculated as 5.26±3.25 mSv.&#x0D; Conclusion: Computed tomography guided transthoracic biopsy procedure are a method with a high diagnostic accuracy rate, low rate of complications and can be preferred in all appropriate pulmonary nodules.

Evaluation of Radiation Dose in Computed Tomography Angiography before Transcatheter Aortic Valve Implantation

Objective: To investigate the effective radiation dose and image quality of computed tomography angiography (CTA) before transcatheter aortic valve implantation (TAVI). Material and Methods: This study involved 65 participants, diagnosed with aortic valve stenosis and examined with CTA before TAVI. The total mAs, kVp, volume CT dose index (CTDIvol), and dose–length product (DLP) in each scanning phase were recorded. The effective dose was calculated by multiplying the DLP by the conversion coefficient (k=0.015 mSv/[mGy.cm]). For quantitative image analysis, circular regions of interest were placed on six levels of the aorta in the axial images. The CT attenuation value, image noise, signal-to-noise ratio, and contrast-to-noise ratio were measured. For qualitative analysis, two radiologists rated the image quality of the aortic root and aortoiliac pathway. Results: The mean CTDIvol and DLP were 23.59±5.19 mGy and 881.01±193.41 mGy.cm., respectively. The mean effective dose was 13.22±2.90 mSv; the whole-aorta CTA phase received the highest dose, followed by the coronary CTA and coronary artery calcium scoring phases (9.62±2.60, 2.44±1.13, and 1.16±0.55 mSv, respectively). Image quality ranged from good to excellent in all segments of the aorta. Conclusion: The mean effective radiation dose of the pre-TAVI CT examination using 256-multidetector CT was 22.91± 5.03 mSv. The image quality in the aorta was good to excellent. The main factors that affected the radiation dose were: body mass index, total mAs, and kVp.

Low-dose abdominopelvic computed tomography in patients with lymphoma: An image quality and radiation dose reduction study.

This study aimed to evaluate image quality, the detection rate of enlarged lymph nodes, and radiation dose exposure of ultralow-dose and low-dose abdominopelvic computed tomography (CT) in patients with lymphoma. Patients with lymphoma who underwent abdominopelvic CT using dual-source scanner were retrospectively recruited from a single center. CT images were obtained at 90 kVp dual-source mode reformatted in three data sets using the advanced modelled iterative reconstruction algorithm: 100% (standard-dose CT), 66.7% (low-dose CT), and 33.3% (ultralow-dose CT). Two radiologists analyzed subjective image quality and detection of abdominal enlarged lymph nodes on ultralow-dose, low-dose, and standard-dose CT blindly and independently. The results were compared with reference standards. Three readers (two radiologists and one hematologist) reviewed overall image quality and spleen size. In total, 128 consecutive CT scans (77 complete response, 44 partial response, 6 progressive disease, and 1 initial evaluation) from 86 patients (64 B-cell lymphoma, 14 T/NK-cell lymphoma, and 8 Hodgkin’s lymphoma cases) were assessed. The enlarged lymph node-based detection rates for two readers were 97.0% (96/99) and 94.0% (93/99) on standard-dose CT, 97.0% (96/99) and 94.0% (93/99) on low-dose CT, and 94.0% (93/99) and 89.9% (89/99) on ultralow-dose CT. Overall image quality was 3.8 ± 0.5, 3.9 ± 0.5, and 4.1 ± 0.5 on ultralow-dose CT; 4.7 ± 0.4, 4.6 ± 0.5, and 4.8 ± 0.3 on low-dose CT; and 4.8 ± 0.4, 4.7 ± 0.4, and 4.9 ± 0.2 on standard-dose CT, according to two radiologists and one hematologist, respectively. Intraclass correlation coefficients of spleen size were 0.90 (95% confidence interval [CI], 0.87–0.93), 0.91 (95% CI, 0.88–0.93), and 0.91 (95% CI, 0.88–0.93) on ultralow-dose, low-dose, and standard-dose CT, respectively. Mean effective radiation doses of standard-dose, low-dose, and ultralow-dose CT were 5.7 ±1.8 mSv, 3.8 ± 1.2 mSv, and 1.9 ± 0.6 mSv, respectively. Our findings suggest that ultralow-dose and low-dose CT, even with radiation doses reduced by 66.7% and 33.3%, respectively, maintained adequate image quality. These imaging modalities may be employed for follow-up lymphoma evaluation in consideration of the long surveillance periods.