64-slice Multidetector Computed Tomography Research Articles

Diagnostic accuracy of lower-dose cardiac CT in evaluating young infants with non-coronary complex congenital heart disease on a 64-slice multidetector CT scanner.

Redoable precise and non-invasive diagnostic imaging modality with the least radiation dose is essential for infants with congenital heart disease (CHD) . To investigate the accuracy and estimate the radiation dose of our cardiac computed tomography (CCT) protocol. A total of 82 infants with CHD underwent non-ECG-gated CCT without contrast timing scanning techniques and were retrospectively studied. The image quality and radiation dose were estimated. The radiation dose was compared statistically to virtual retrospective ECG-gated and prospective ECG-triggering scanning modes. The diagnostic accuracy was assessed assuming the surgical results as the diagnostic gold standard. Most exams showed a high quality with low radiation doses compared to previous studies. The mean effective dose (ED) was 0.39 ± 1.2, significantly lower than that of the virtual retrospective ECG-gated and prospective ECG-triggering scanning and lower than in previous studies. Our CCT protocol has achieved a diagnostic accuracy of 99.52% with a sensitivity of 94.83% and specificity of 99.91%. Non-ECG-gated CCT without contrast timing techniques can detect the non-coronary cardiovascular defects of CHD in infants with an ultralow radiation dose and a high diagnostic accuracy.

Abstract 14663: The Impact of Continuous Positive Airway Pressure for Sleep Apnea on Left Atrial Dilatation in Patients Receiving Catheter Ablation of Atrial Fibrillation

Background Sleep apnea (SA) and left atrial dilatation (LA) are both risk factors for an arrhythmia recurrence after catheter ablation (CA) of atrial fibrillation (AF). Negative intrathoracic pressure fluctuations during an obstructive apnea episode may cause the left atrium to distend and stretch its wall. However, the impact of continuous positive airway pressure (CPAP) for SA on the reverse LA remodeling has not been elucidated. Methods This study was conducted under a retrospective, single-center, observational design. Data was derived from screening tests for sleep apnea, which were routinely performed in patients scheduled to receive CA of AF in our institution. The severity of the sleep apnea was evaluated by the apnea-hypopnea index (AHI). After excluding patients who were already diagnosed with sleep apnea, we enrolled 1232 consecutive patients who underwent multidetector computed tomography (MDCT) both before and 3-months after the CA of AF. The left atrial dilatation and volume reduction were evaluated by the left atrial minimum volume (LA min V) using 256-slice MDCT. Results The age was 65±11 years, 27.8% were females, and 46.0% had non-paroxysmal AF. The mean AHI was 20.2±15.2 and LA min V 79.1± 37.8ml (r=0.31, p<0.0001) before CA. LA dilatation was defined as an LA min V≥79.1ml. After an adjustment by an advanced age (≥65 years), non-paroxysmal AF, male sex, obesity, hypertension, diabetes, and congestive heart failure, SA (AHI≥5) was a significant predictor of LA dilatation before CA (odds ratio 2.83, 95% confidence interval 1.55-5.16, p=0.0007). After CA, 206 out of 1092 patients (18.9%) with SA started CPAP. SA patients with CPAPs had a greater LA min V reduction rate on the postprocedural CT than those without CPAP (26.2% vs. 20.5%, p=0.013). Conclusion Among the patients scheduled to receive catheter ablation of AF, SA was independently associated with left atrial dilatation. Patients who started CPAP treatment for SA had greater LA reverse remodeling at 3 months after the CA.

Gross anatomy, computed tomography, magnetic resonance imaging and bone mineral densitometry of the ovine metacarpo/metatarsophalangeal joint.

This study was aimed to provide anatomical atlas of the ovine metacarpo/metatarsophalangeal joints using computed tomography (CT) scan and magnetic resonance imaging (MRI), as well as to investigate bone mineral density (BMD) and morphometric features of this joint. The limbs of twenty adult Sanjabi sheep were examined. Imaging was performed using a 16-slice multi-detector CT scanner and a 1.5 Tesla MRI scanner. The obtained images were correlated with corresponding anatomical sections. BMD was measured by Dual Energy X-ray Absorptiometry (DEXA) method. Also morphometric features included distance between metacarpal and metatarsal heads, width of metacarpal and metatarsal head, length, width and the height of the proximal sesamoid bones were measured. In MRI images, compact bones, ligaments and tendons showed less signal intensity (hypointense). The fatty tissue and bone marrow had more signal intensity (hyperintense), but articular cartilage and synovial fluid showed moderate signal intensity. BMD in the left hind limb was significantly higher than other three limbs (p ≤0.05). The length of proximal sesamoid bones in left forelimb was higher than right forelimb (p ≤ 0.05). The thickness of proximal sesamoid bones in left limbs was higher than those in their counterparts (p ≤ 0.05). The width of the medial head in the forelimbs was significantly greater than the hind limbs (p ≤ 0.05). The present results might be useful in managing the clinical techniques on this joint. Larger volume of the proximal sesamoid bones and wider medial head in the forelimbs compared to the hindlimbs impel this speculation that the centre of gravity is closer to the forelimbs.

Untreated sleep apnea and left atrial dilatation in patients with atrial fibrillation prior to catheter ablation

Abstract Background Sleep apnea and left atrial dilatation are both risk factors for an arrhythmia recurrence after catheter ablation (CA) of atrial fibrillation (AF). Negative intrathoracic pressure fluctuations during an obstructive apnea episode may cause the left atrium to distend and stretch its wall. Whether sleep apnea is associated with left atrial dilatation in patients receiving CA of AF remains unknown. Purpose We sought to elucidate whether moderate or severe untreated sleep apnea was associated with left atrial dilatation in patients with AF before CA. Methods This study was conducted under a retrospective, single-center, observational design. The data were derived from screening tests for sleep apnea, which were routinely performed in patients scheduled to receive CA of AF in our institution. After excluding patients who were already diagnosed with sleep apnea, we enrolled 1265 consecutive patients (age 65±11 years, 27.8% females, and 46.2% of non-paroxysmal AF) who underwent both home sleep apnea testing and multidetector computed tomography (MDCT) before the CA of AF. The severity of the sleep apnea was evaluated by the apnea-hypopnea index (AHI) using a watch-type peripheral arterial tonometry. Left atrial dilatation was evaluated by the left atrial maximum volume (LA max V) using 256-slice MDCT. Results The age was 65±11 years, 27.8% were females, and 46.2% had non-paroxysmal AF. The mean AHI was 20.3±15.3 and LA max V 105±34 ml (R2=0.075, p<0.0001). LA dilatation was defined by larger than mean LA max V (LA max V≥105 ml). We examined an LA max V≥105 ml as a predictor. After an adjustment by an advanced age (≥65 years), non-paroxysmal AF, male sex, obesity, hypertension, and congestive heart failure, all of which were significant predictors of an LA max V≥105ml in the univariate analysis, moderate or severe sleep apnea (AHI≥15) was a significant predictor of an LA max V≥105 ml (odds ratio 1.63, 95% confidence interval 1.24–2.14, p=0.0005). Conclusion Among the patients scheduled to receive catheter ablation of AF, moderate or severe sleep apnea was independently associated with left atrial dilatation. Funding Acknowledgement Type of funding sources: None.

Detection of Coronary Artery and Aortic Arch Anomalies in Patients with Tetralogy of Fallot Using CT Angiography.

Background: Tetralogy of Fallot (TOF) is the most common form of cyanotic congenital heart disease (CHD). Furthermore, the prevalence of anomalous origin of a coronary artery is higher in patients with TOF than in the general population (6% vs. ≤1%). Preoperative assessment of cardiovascular anatomy using computed tomography (CT) angiography enables the adaptation of the surgical approach to avoid potentially overlooked anomalies. Our purpose was to determine the prevalence of coronary artery and aortic arch anomalies in a cohort of TOF patients. Methods: In this retrospective analysis, data were collected from CT reports (2015–2021) of 105 TOF patients. All images were acquired using a 64-slice multi-detector CT (MDCT) scanner. Results: The median age of the patients was 38.7 months, with a male-to-female ratio of 1.39. The overall prevalence of coronary artery anomalies (CAAs) was 7.61% (8 of 105 cases). The anomalous origin and course of coronary arteries across the right ventricular outflow tract (RVOT; prepulmonic course) were defined in 5.71% of cases (six patients). In four of these, the left anterior descending artery (LAD) originated from the right coronary artery (RCA), while in two cases, the RCA arose from the LAD. In the remaining two patients, the coronary arteries followed an interarterial course. The most frequent anomalous aortic arch pattern in the overall TOF population was the right aortic arch (RAA) with mirror image branching, seen in 20% of patients (21 cases). The most frequent anomaly of the supra-aortic trunks was bovine configuration, found in 17.14% (18 cases). Conclusions: The prevalence of CAAs and aortic arch anomalies detected by CT angiography was in line with the data reported in anatomical specimens. Therefore, this technique represents a powerful tool for the evaluation of congenital cardiovascular anomalies.

3D render volume CT reconstruction of the bones and arteries of the hind digit of the dromedary camel (Camelus dromedarius)

BackgroundThe 3D computed tomography produces detailed images of the digit bones in addition to the angiograph render volume 3D of the CT shows the relation between the arteries, bones, and tissues of the digit. Therefore, the present study used those imaging techniques to provide a complete description of the digit bones and arteries’ origin, distribution, and course and their relations with surrounding structures in the Dromedary Camel. Which would serve as a guide for surgeons and students in distinguishing normal digit structures. The study used eight hind limbs of four adult camels of both sexes (two males and two females), aged 9–15 years (Mean ± SD, 11.80 ± 2.59 years). The samples were injected with latex with lead oxide were undergone 3D render volume CT (128-slice multi-detector CT scanning protocol) and angiography x-rays.ResultsThe blood vessels and correlated structures such as bones, tendons, and ligaments were examined using 3D CT in all directions, which was easier to view than angiography and dissected specimens. The arterial supply to the camel’s hind foot was the A. digitalis plantaris communis III. The angiography render volume 3D of CT explained the blood supply of the bones and joints of digital regions and showed a good visualization of the many digit arteries. The metatarsals, the phalanges, and the sesamoid bones were visualized. A. plantaris medialis superficialis, A. digitalis plantaris communis III, A. digitalis plantaris communis II and IV, A. interdigitalis, rami articularis medialis and lateralis to the fetlock joint, ramus medialis and ramus lateralis of the A. digitalis plantaris communis III, A. digitalis plantaris propriae III et IV abaxialis, A. digitalis plantaris propriae III et IV axialis, Ramus phalangis axialis and abaxialis of the first phalanx, Ramus phalangis axialis and abaxialis of the second and third phalanges, and A. metatarsae plantaris III were visualized. The study discovered new blood vessel sources in dromedary camels, such as the ramus articularis to the fetlock and the ramus plantaris phalangis abaxialis proximalis and distalis of the first phalanx.ConclusionsThe digital circulation angiography investigates the circulatory pattern of the camel hind digit, which can assist clinicians in diagnosing digit region affections. 3D CT explained improved visualization of bones and arteries, including many small branches in relation to surrounding structures, in some views better than others.

A novel dual-energy cone beam computed tomography device for assessment of jaw bone density

<h3>Objective</h3> To evaluate a novel dual-energy cone beam computed tomography (DE-CBCT) device for jaw bone density assessment. <h3>Study Design</h3> An ongoing clinical trial has enrolled 19 subjects with a target enrollment of 24 subjects. All subjects were 21 years and older and required a maxillofacial CT scan for standard-of-care diagnosis. Each subject received 2 examinations: one with a 64-slice multi-detector CT (MDCT) scanner and the second with the experimental DE-CBCT device (RCT720, Ray Co. Seoul, Korea). Asynchronous scanning of a custom hydroxyapatite phantom (concentrations of 0.8, 1.0 and 1.2 g/cc) provided calibration for bone density measurement. DICOM data from both CT examinations were imported into a custom version of OnDemand software<i>.</i> Calibration curves were generated from the MDCT and DE-CBCT scans of the hydroxyapatite phantoms. The MDCT and DE-CBCT scans of study subjects were superimposed and custom tools allowed calculation of bone density within a specified region of interest (ROI). Concordance between the MDCT- and DE-CBCT-derived bone densities was examined. <h3>Results</h3> In our preliminary assessments of data from current subjects, the mean calculated bone density in all the ROIs measured was 0.51 ± 0.27 g/cc for MDCT imaging and 0.50 ± 0.32 for DE-CBCT imaging. The range of the calculated bone densities was 0.06 to 1.1 g/cc for MDCT and 0.04 to 1.3 g/cc for DE-CBCT. Overall, there was strong correlation between bone densities calculated from MDCT scans with those calculated from DE-CBCT scans (r = 0.96, p <0.0001). Bland-Altman analysis identified a bias of 0.01 ± 0.1, and 95% limits of agreement range was -0.19 to 0.21. <h3>Conclusion</h3> The RCT720, a newly-developed DE-CBCT device, produced measurement of bone density equivalent to MDCT and overcomes the inaccuracies of bone density assessment using conventional CBCT scans. <b>Statement of Ethical Review</b> Human/Animal subjects were used and this study was approved by an institutional ethics panel

COMPARISON OF LOW KVP SIZE BASED LOW DOSE CT PROTOCOL AND LOW KVP AUTOMATED EXPOSURE CONTROLLED BASED LOW DOSE CT PROTOCOL, FOR EVALUATION OF CONGENITAL HEART DISEASE IN PAEDIATRIC POPULATION IN A TERTIARY CARE TEACHING HOSPITAL OF WESTERN RAJASTHAN.

ntroduction: Evaluation for CHD lead to inadvertent radiation exposure to children. With objective of minimising radiation exposure, we developed a size based (SB) novel low kVp low dose CT protocol for pediatrics population. All CT chest examinationsMaterial and methods: performed on PHILIPS Ingenuity core 64-slice multi detector CT machine. A total of sixty children with suspected/diagnosed CHD were randomized to either novel SB protocol or machine's default AEC based low dose pediatric chest CT protocol . Our protocol consisted of keeping tube voltage 80 kVp in all patients and tube current (mA) being modulated according to size of subjects (chest circumference). All CT dose parameters (ED, CTDI vol, DLP and mA) were recorded for comparison. Image quality of the two methods compared by two radiologists blinded to the method. After analysing and comparing with other studies for all the CT dose variables we concluded that all CT radiation exposureResults: values as measured by ED, CTDI vol, SSDE, DLP were lower in SB protocol as comparison to default AEC based protocol in those corresponding to &lt;12 months age group. In 1-5 year- ED, SSDE, CTDI vol and DLP was equivalent in both size based and AEC based low dose protocols. In 6-18 year ED, SSDE, CTDI vol and DLP was slightly higher in size based low dose protocol. In younger age group ( &lt;12 months of age) SBConclusion: protocol should be preferred as compared to default machine protocol. In children with &gt;1 years of age , low dose AEC protocol is better from perspective of radiation exposure.

Multidetector Computed Tomography Perfusion in Head and Neck Squamous Cell Carcinomas: Evaluation of a Dose Reduction Strategy.

Background Computed tomography perfusion (CTp), a useful technique in oncology, is not widely utilized due to the high radiation dose delivered from it. It involves scanning the region of interest every second for 50 seconds following intravenous contrast administration. Doubling sampling interval (SI) to 2 seconds will half the radiation dose, but may impact its effectiveness, which needs to be evaluated. Objectives To evaluate a dose reduction strategy in CTp by determining agreement between standard dose (SD) CTp (acquisition with SI 1 second) and low-dose CTp techniques with SI of 2 seconds (achieved either by reconstruction only or true low-dose acquisition). Materials and methods This cross-sectional study was conducted on histopathology-proven head and neck squamous cell carcinoma (HNSCC) patients who underwent CTp on 64 slice multidetector CT. A total of 56 patients had SD and 24 patients underwent true low dose (LD) acquisition. SD data were also reconstructed at SI 2 seconds to obtain a dataset simulating low dose (low-dose reconstruction [LDr]). Paired t -test was applied to compare CTp in SD and LDr groups and the Bland-Altman plot drawn to calculate 95% confidence limit of agreement. The Kolmogorov-Smirnov test compared CTp parameters for LDr and LD groups. Results There was no statistical difference in CTp parameters (except blood flow in malignant) in SD and LDr groups for both malignant and normal tissues. CTp of malignant tissue was not statistically different in LDr and LD groups but the radiation dose was half in the LD group. Conclusion Reduction of radiation dose to half achieved by doubling the SI does not affect the CTp parameters significantly. So LD acquisitions will increase the use of CTp in HNSCC.

Analysis of Anatomical Variations of the Main Arteries Branching from the Abdominal Aorta by Multidetector Computed Tomography

Introduction: Embryological development of the aorta being a complex process can lead to a variety of congenital variants. It may result in complications during abdominal laparoscopic and radiological interventions. Prior knowledge can identify the anatomy, which may require special attention at the time of surgery/interventions. Diagnostic imaging with multidetector computed tomography (MDCT) allows accurate and noninvasive preoperative evaluation. To identify and to evaluate the anatomical variation of major arteries branching from the abdominal aorta using MDCT. Material and Methods: Five hundred patients of different age groups referred to the Department of Radiodiagnosis, Dayanand Medical College and Hospital, Ludhiana, for MDCT abdomen were included in the study. It was performed on 128-slice MDCT Siemens Somatom Definition AS scan machine. Results: The results showed that anatomical variation occurs in a high percentage of patients. In the celiac axis, it occurred in 34.6% of cases, out of which the most common variant was a replaced right hepatic artery (3.7%). Celiacomesenteric trunk was observed in 0.2% of patient. Single renal artery was observed (43.2%) while accessory renal artery in 41.6% and early branching in 15.2%. Discussion and Conclusion: Prior knowledge of variations of these vessels can prevent iatrogenic injuries.

Spinal Canal Measurements at the Level of Lower Three Lumbar Vertebrae by 128-Slice CT Scanner in Bangladeshi Population

Background &amp; objective : The knowledge of normal diameter of lumbar spinal canal is very important for diagnosing lumbar spinal canal stenosis and also for performing spinal surgeries at the lumbar level by Neurosurgeons and Orthopedicians. However, it varies widely among ethnic groups and between sexes in the same ethnic group. The present study was conducted to describe the morphometry of lumbar vertebrae at the level of L3-L5.&#x0D; Methods: This descriptive cross-sectional study was conducted on 302 patients (aged 20-60 years) at Ibrahim Cardiac Hospital &amp; Research Institute between July 2019 to December, 2020 who underwent diagnostic CT scans for abdominal or genitourinary complaints without any known vertebral column pathology or complaints of low back pain or other abnormalities attributable to lumbar spine. Patients having sciatic pain with or without pain in the back, having past history of back surgery and patients with osteophytes or developmental anomalies, trauma or vertebral fracture and known case of lordosis, scoliosis or kyphosis or other abnormalities in lumbar vertebrae were also excluded. A CT scan was performed using 128-slice multi-detector CT with unenhanced CT images from the level of diaphragm to pubic symphysis so that the area from D12 to S1 vertebra be covered (field of view). Sections 3-mm thick with reconstruction up to 1 mm were analyzed and different parameters of the spinal canal and vertebral body were measured in sagittal and transverse sections. The images were reconstructed in true axial, coronal, and sagittal planes. The canal-body ratio (CBR) was determined by dividing the sagittal diameter of the spinal canal by the sagittal diameter of the vertebral body.&#x0D; Result: The findings of the present study demonstrate that nearly two-thirds (65.5%) of the subjects were early middle-aged or middle-aged with mean age of the subjects being 43 years. A male predominance was observed in the series with male to female ratio being 4:1. The study revealed that all the dimensions of the canal and the body in transverse and sagittal sections were observed to increase from level L3 to L5, while the canal body ratio was decreased slightly from L3-L5. The males have significantly wider vertebral body at all levels (L3-L5) of lumbar vertebrae compared to their female counterparts. Vertebral body diameter in sagittal section at L3 was significantly greater in males than those in females; however, they were not different between sexes at L4 and L5 levels. Canal-body ratio (CBR) was fairly comparable between males and females at L3 and L4, but it was greater in males than that in females at L5. No significant difference was observed between L3 &amp; L4 and L4 &amp; L5 in the same individuals in terms of CBR.&#x0D; Conclusion: The study concluded that there are significant variations in some of the lumbar spinal canal dimensions and vertebral body measurements (including CBR) from L3-L5 between males and females. Although there was no significant difference between L3 and L4 in the same individuals in terms of CBR, there was reasonable difference between L4 and L5 lumbar vertebrae. The findings are of much significance in the investigation of vertebral column pathology in the context of our population.&#x0D; Ibrahim Card Med J 2021; 11 (1): 8-13

Low-dose multi-detector computed tomography for periradicular infiltrations at the cervical and lumbar spine

Periradicular infiltrations are frequently performed in daily neuroradiological routine and are often guided by multi-detector computed tomography (MDCT), thus leading to radiation exposure. The purpose of this study was to evaluate MDCT with low dose (LD) and model-based iterative reconstruction for image-guided periradicular infiltrations at the cervical and lumbosacral spine. We retrospectively analyzed 204 MDCT scans acquired for the purpose of cervical or lumbosacral periradicular interventions, which were either derived from scanning with standard dose (SD; 40 mA and 120 kVp) or LD (20–30 mA and 120 kVp) using a 128-slice MDCT scanner. The SD cases were matched to the LD cases considering sex, age, level of infiltration, presence of spinal instrumentation, and body diameter. All images were reconstructed using model-based iterative image reconstruction and were evaluated by two readers (R1 and R2) using 5- or 3-point Likert scales (score of 1 reflects the best value per category). Furthermore, noise in imaging data was quantitatively measured by the standard deviation (StDev) of muscle tissue. The dose length product (DLP) was statistically significantly lower for LD scans (6.75 ± 6.43 mGy*cm vs. 10.16 ± 7.70 mGy*cm; p < 0.01; reduction of 33.5%). Image noise was comparable between LD and SD scans (13.13 ± 3.66 HU vs. 13.37 ± 4.08 HU; p = 0.85). Overall image quality was scored as good to very good with only minimal artifacts according to both readers, and determination of the nerve root was possible in almost all patients (LD vs. SD: p > 0.05 for all items). This resulted in high confidence for intervention planning as well as periprocedural intervention guidance for both SD and LD scans. The inter-reader agreement was at least substantial (weighted Cohen’s κ ≥ 0.62), except for confidence in intervention planning for LD scans (κ = 0.49). In conclusion, considerable dose reduction for planning and performing periradicular infiltrations with MDCT using model-based iterative image reconstruction is feasible and can be performed without clinically relevant drawbacks regarding image quality or confidence for planning.

Evaluating the performance of unenhanced computed tomography in the diagnosis of pulmonary embolism

Abstract Funding Acknowledgements Type of funding sources: None. Background Pulmonary embolism (PE) is the third most common cardiovascular pathology after coronary artery disease and stroke with an incidence rate of 1 per 1000 individuals. Computed tomography pulmonary angiography (CTPA) as the gold standard examination in the detection of PE is contraindicated or unavailable in certain cases. Purpose The current study aimed to assess the accuracy of unenhanced CT in the diagnosis of PE. Methods A total of 195 consecutive participants with clinical suspicion for PE were enrolled in this prospective cohort study between October 2020 and March 2021. All patients were examined with a 16 slice multidetector (MD) CT scanner before performing the CTPA. Scans were independently reviewed by two expert radiologists who were blinded to patients’ clinical and laboratory history for imaging variables including presence and location of PE, hyper/hypodense intraluminal signs, pulmonary trunk enlargement, peripheral wedge-shaped opacity, and pleural effusion. First unenhanced CT scan and then CTPA were independently reviewed on a picture archiving and communications system workstation. Results There were 82 (42.1%) men and 113 (57.9%) women with the mean age ± standard deviation of 56 ±0.24 years. Based on CTPA results, 47 (24.1%) of 195 patients had PE of which 28 (59.5%) patients had central PE and 19 (40.5%) patients had peripheral PE. However, only 20 cases (42.5%) were detected with PE on MDCT scans consisting of 17 cases with (85%) central emboli and 3 cases with (15%) peripheral emboli. Given intraluminal clot density, 12 (60%) patients had hyperdense signs, 3 (15%) patients had hypodense signs, and 5 (25%) patients had mixed hyper-hypodense signs. There was a significant difference between central and peripheral embolies detected by MDCT. Intraluminal sign had the highest specificity and sensitivity (98.6%, 42.5%, AUC:0.734) followed by pulmonary trunk enlargement (84.4%, 36.1%, AUC: 0.603), peripheral wedge-shaped opacity (72.9%, 34%, AUC: 0.535), and pleural effusion (58.7%, 40.4%, AUC: 0.496). Our results did not show a remarkable difference in secondary findings from the MDCT scan including pulmonary trunk enlargement, peripheral wedge-shaped opacity, and pleural effusion concerning the presence of PE. Pleural effusion as the most common secondary finding in patients with PE was found in 31 (68.8%) of them. Conclusion Unenhanced MDCT has an acceptable performance to detect PE particularly central clots and should be considered as an alternative modality when CTPA is not available or indicated. Furthermore, the intraluminal sign is the main indicator of PE in MDCT images with the highest specificity and sensitivity. We recommend radiologists and other clinicians to be aware of intraluminal signs in case of unexpected PE.

Effect of Body Mass Index in Coronary CT Angiography Performed on a 256-Slice Multi-Detector CT Scanner.

We aimed to investigate the effect of a patient’s body mass index (BMI) on radiation dose and image quality in prospectively ECG-triggered coronary CT angiography (CCTA) performed on a 256-slice multi-detector CT scanner. In total, 87 consecutive patients receiving CCTA examinations acquired with tube current modulation (TCM) and iterative reconstruction (IR) were enrolled in this study. The dose report recorded from the CT scanner console was used to derive the effective dose for patients. Subjective image quality scoring and objective noise measurements were conducted to quantify the impact of BMI on the image quality of CCTA. Because of the TCM technique, we expected tube current and radiation dose to increase as BMI increased. However, using TCM did not always guarantee sufficient radiation exposure to achieve consistent image quality for overweight or obese patients since the maximum X-ray tube output in milliamperes and kilovoltage peak was reached. The impact of photon starvation noise on image quality was not significant until BMI ≥ 27 kg/m2; this result could be due to IR’s noise reduction capability. Our results also suggest that using TCM with a noise index of 25 HU can reduce radiation dose without compromising image quality compared to images obtained based on the manufacturer’s default settings.

Role of Coronary Calcium Score as a Screening Tool for Excluding Significant Coronary Artery Disease in High Risk Asymptomatic Patients

OBJECTIVES: To determine correlation of zero coronary artery calcium score (CACS) with non-significant coronary artery stenosis by using computed tomography coronary angiography (CTCA). METHODOLOGY: 62 patients with suspected coronary artery disease (CAD) underwent CACS test and CTCA from April 2018 to November 2020. Patients were examined with 160 slice multidetector CT and grouped according to their age, gender, CACS, and maximum coronary luminal stenosis. CACS was assessed using Agatston scoring and degree of stenosis was assessed by automatic software and severity was scored according to CAD-RADS. The correlation between these two main variables was calculated using Spearman rank correlation. RESULTS: The 62 patients were divided into four groups according to CACS, using the Agatston Unit (AU). Group 1; 0 AU (41 patients, 66.13%), Group 2; 1-100 AU (13 patients, 20.97%) Group 3; 101-400 AU (4 patients, 6.45%), Group 4; 401-1000 AU (4 patients, 6.45%). In 41 patients with zero calcium score (32 males and 9 females), 38 patients (92.68%) were found to have no coronary artery stenosis, 2 patients (4.87%) had mild coronary artery stenosis and 1 patient (2.43%) had moderate coronary artery stenosis. Total 35 patients presented for screening purpose out of which 25 (71%) had zero calcium score and no significant coronary artery disease. CONCLUSION: In high risk patients, zero calcium score excludes significant coronary artery stenosis (50%), hence coronary calcium score is a good screening tool before subjecting patients to coronary angiography.

Abstract 14347: Sleep Apnea and Left Atrial Dilatation in Patients With Atrial Fibrillation Prior to Catheter Ablation

Introduction: Sleep apnea and left atrial dilatation are both risk factors for an arrhythmia recurrence after catheter ablation (CA) of atrial fibrillation (AF). Negative intrathoracic pressure fluctuations during an obstructive apnea episode may cause the left atrium to distend and stretch its wall. Whether sleep apnea is associated with left atrial dilatation in patients receiving CA of AF remains unknown. Methods: This study was conducted under a retrospective, single-center, observational design. The data were derived from screening tests for sleep apnea, which were routinely performed in patients scheduled to receive CA of AF in our institution. After excluding patients who were already diagnosed with sleep apnea, we enrolled 1265 consecutive patients (age 65±11 years, 27.8% females, and 46.2% of non-paroxysmal AF) who underwent both home sleep apnea testing and multidetector computed tomography (MDCT) before the CA of AF. The severity of the sleep apnea was evaluated by the apnea-hypopnea index (AHI) using a watch-type peripheral arterial tonometry. Left atrial dilatation was evaluated by the left atrial maximum volume (LA max V) using 256-slice MDCT. Results: The age was 65±11 years, 27.8% were females, and 46.2% had non-paroxysmal AF. The mean AHI was 20.3±15.3 and LA max V 104.9±33.9 ml (R 2 =0.075, p&lt;0.0001). LA dilatation, defined by an LA max V≥100 ml, was more frequently observed in patients with an AHI≥15 than those with an AHI&lt;15 (62.5% vs. 40.2%, p&lt;0.0001). We examined an LA max V≥100 ml as a predictor. After an adjustment by an advanced age (≥65 years), non-paroxysmal AF, male sex, obesity, hypertension, and congestive heart failure, all of which were significant predictors of an LA max V≥100ml in the univariate analysis, moderate or severe sleep apnea (AHI≥15) was a significant predictor of an LA max V≥100 ml (odds ratio 1.49, 95% confidence interval 1.13-1.97, p=0.0049). Conclusion: Among the patients scheduled to receive catheter ablation of AF, moderate or severe sleep apnea was independently associated with left atrial dilatation.

Influence of Prediabetes on Coronary Atherosclerotic Plaque Burden Assessed by Coronary Computed Tomography Angiography (CCTA).

IntroductionAccording to CDC there are 88.0 million Americans aged 18 years or older with prediabetes. Cardiovascular disease is the primary cause of morbidity and mortality in diabetes. The relationship between prediabetes and coronary atherosclerosis is not well established. We evaluated the association between prediabetes and coronary atherosclerosis and compared it to non-diabetic population. MethodsIn this retrospective study all patients who underwent CCTA and coronary artery calcium (CAC) testing at our outpatient imaging center for the past 5 years were screened. 253 patients had recorded HbA1c values and were included in the study. 256 slice multi detector CT (GE Revolution, Milwaukee WI) scanner was used for imaging. CAC was scored using non-contrast CT. Total plaque score (TPS) and total stenosis score (TSS) were quantified using coronary CTA. Each of the scores were compared between prediabetic (125) and non-diabetic groups (128). ResultsMean age of the study cohort was 53.2 ± 17.1 years, 66% were males, 114 had hyperlipidemia (45%), 108 had hypertension (43%), 96 were present smokers (38%) and the mean HbA1c was 5.6 ±0.4. In multivariate adjusted regression models, the odds of TPS (OR:2.93; CI: 1.54,5.57) P<0.001, TSS (OR:2.82; CI:1.48,5.38) P<0.002 and CAC score (OR:3.43; CI: 1.74,6.74) p<0.001, were all higher in prediabetic patients. ConclusionOur findings suggest that prediabetics have higher atherosclerotic plaque burden compared to non-diabetics. In prediabetes, increased plaque burden most likely contributes to cardiovascular events. The application of these findings may guide early screening and pharmacological prevention strategies for atherosclerosis in patients with prediabetes.

Application of Deep Learning Reconstruction Algorithm in Low-Dose Thin-Slice Liver CT of Healthy Volunteers

To explore the clinical feasibility of applying deep learning (DL) reconstruction algorithm in low-dose thin-slice liver CT examination of healthy volunteers by comparing the reconstruction algorithm based on DL, filtered back projection (FBP) reconstruction algorithm and iterative reconstruction (IR) algorithm. A standard water phantom with a diameter of 180 mm was scanned, using the 160 slice multi-detector CT scanning of United Imaging Healthcare, to compare the noise power spectrums of DL, FBP and IR algorithms. 100 healthy volunteers were prospectively enrolled, with 50 assigned to the normal dose group (ND) and 50 to the low dose group (LD). IR algorithm was used in the ND group to reconstruct images, while DL, FBP and IR algorithms were used in the LD group to reconstruct images. One-way analysis of variance was used to compare the liver CT values, the liver noise, liver signal-to-noise ratio (SNR), contrast noise ratio (CNR) and figure of merit (FOM) of the images of ND-IR, LD-FBP, LD-IR and LD-DL. The Kruskal-Wallis test was used to analyse subjective scores of anatomical structures. The DL algorithm had the lowest average peak value of noise power spectrum, and its shape was similar to that of medium-level IR algorithm. Liver CT values of ND-IR, LD-FBP, LD-IR and LD-DL did not show statistically significant difference. The noise of LD-DL was lower than that of LD-FBP, LD-IR and ND-IR ( P<0.05), and the SNR, CNR and FOM of LD-DL were higher than those of LD-FBP, LD-IR and ND-IR ( P<0.05). The subjective scores of anatomical structures of LD-DL did not show significant difference compared to those of ND-IR ( P >0.05), and were higher than those of LD-FBP and LD-IR. The radiation dose of the LD group was reduced by about 50.2% compared with that of the ND group. The DL algorithm with noise shape similar to the medium iterative grade IR commonly used in clinical practice showed higher noise reduction ability than IR did. Compared with FBP, the DL algorithm had smoother noise shape, but much better noise reduction ability. The application of DL algorithm in low-dose thin-slice liver CT of healthy volunteers can help achieve the standard image quality of liver CT.

The role of multidetector computed tomography in the diagnosis and assessment of patients with hemoptesis

Objective This study aims to assess the role of multidetector computed tomography (MDCT) in the diagnosis and assessment of patients with hemoptesis. Patients and Methods This was a prospective study carried out on a total of 20 patients who presented with hemoptysis, all referred from the Chest Department and clinic to the Radiology Department in El-Zahra Hospital for 164 slice MDCT examination; the study was carried out for a period of 1 year from January 2020 to January 2021 after receiving approval from the ethical committee of the institute. Informed consent was obtained from all patients before inclusion in the study. Results The MDCT study showed that bronchogenic carcinoma was found to be the most common cause of hemoptysis in six (30%) patients, pulmonary embolism and bronchiectasis were found in four (20%) patients, in two (10%) patients, metastasis was present due to breast and testicular cancer, and one (5%) patient, lung abscess, pulmonary hypertension, tuberculosis, and alveolar hemorrhage were present. Conclusion MDCT proved to be the imaging modality of choice in the diagnosis of hemoptysis, being superior to chest radiography in demonstrating not only causes of delay but also the extent of lung abnormalities.

Pattern of injuries in blunt trauma abdomen: A retrospective evaluation of imaging findings at a high-volume tertiary care trauma centre

Objective: Contrast-enhanced computed tomography (CECT) is the investigation of choice in trauma patients. The purpose of this study was to retrospectively evaluate the pattern, severity and association of abdominal injuries based on imaging at a high-volume tertiary trauma care centre. Methods: Retrospective evaluation of the CT records of patients over a period of 5 years was done at our institute. A total of 1519 patients who had undergone contrast-enhanced abdominal CT at a 64-slice Multidetector CT for abdominal trauma were included in this study. Inclusion criteria were: 1) History of blunt abdominal trauma, 2) Patients who had undergone a biphasic CECT abdomen scan. Exclusion criteria were: 1) Patients with penetrating injury, 2) Patients with incomplete data set/records. Results: Liver was the most common injured organ in both adult (38.8%) and paediatric population (40.9%). Significant higher incidence of mesenteric injury, bladder injury, spinal and rib fractures were seen in adult patients. Significant association of anorectal injuries (P=0.003) and bladder/urethral injuries with pelvic fractures was also seen (P&lt;0.001). Conclusion: Our study provided important insights about the pattern, severity and association between the various abdominal injuries based on imaging findings in a large patient population. Larger studies with incorporation of clinical outcome in such patients can help in formulating appropriate management strategies.