Abstract WP72: Low kV Computed Tomography Cerebral Angiogram Using Third-Generation Reconstruction Algorithm Provides Significantly Improved Image Quality With Lower Contrast and Radiation Exposure

Stroke ◽  
2020 ◽  
Vol 51 (Suppl_1) ◽  
Author(s):  
Girish Bathla ◽  
Sarv Priya ◽  
Neetu Soni ◽  
Colin Derdeyn
Keyword(s):  
Image Quality ◽  
Radiation Exposure ◽  
Basilar Artery ◽  
Reconstruction Algorithm ◽  
Third Generation ◽  
Cerebral Angiogram ◽  
Subjective Image Quality ◽  
Contrast Dose ◽  
Significant Difference ◽  
Lower Contrast

Introduction/Aim: We aimed to determine if CTA imaging using third generation reconstruction algorithm and lower contrast dose-low kVp technique (LD-CTA) was comparable to regular contrast dose CTA at 120 kVp using a sinogram affirmed iterative reconstruction algorithm (ND-CTA). Methods: Retrospective imaging review of 100 consecutive patients (50 each in LD- and ND-CTA groups). Two readers independently assessed the subjective image quality across multiple vascular segments on a Likert-like scale. Contrast- and signal-to-noise ratios (CNR/ SNR) were compared for the mid-M1-MCA vessels bilaterally and the mid-basilar artery. Fisher’s exact test was used to compare subjective image quality. Interclass correlation coefficient (ICC) was calculated for the SNR/CNR values. Finally differences in contrast dose, CT-dose index (CTDI) and dose length product (DLP) were compared using Mann-Whitney U test. Results: Both observers showed excellent correlation in subjective image quality (mean percentage agreement of 95.2% (84-100%) for group-1 versus 89.2% (82%-98%) for group-2). The subjective scores were not statistically different in the anterior circulation but showed significantly better image quality for the basilar artery. LD-CTA group showed significantly better SNR and CNR (p < 0.0001) for both MCA vessels and the basilar artery. ICC showed moderate correlation (0.51-0.63) between the observers. Student paired t-test did not show any significant difference between the observers. LD-CTA group also used lower contrast (49 cc versus 103 cc in ND-CTA) and had lower radiation exposure (DLP/ CTDI for both groups 268.3/12.42 vs 519.5/ 25.15, both < 0.0001). Conclusion: Next-generation reconstruction algorithm and low-Kv scanning significantly improved image quality on cerebral CTA images despite lower contrast dose, and in addition, have lower radiation exposure.

Model-based reconstruction algorithm in the detection of acute trauma-related lesions in brain CT examinations

2021 ◽  
pp. 197140092110087
Author(s):  
Andrea De Vito ◽  
Cesare Maino ◽  
Sophie Lombardi ◽  
Maria Ragusi ◽  
Cammillo Talei Franzesi ◽  
...  
Keyword(s):  
Image Quality ◽  
Iterative Reconstruction ◽  
Signal To Noise Ratio ◽  
Reconstruction Algorithm ◽  
Signal To Noise ◽  
Subjective Image Quality ◽  
Model Based ◽  
Hybrid Iterative Reconstruction ◽  
Noise Ratio ◽  
Enhanced Computed Tomography

Background and purpose To evaluate the added value of a model-based reconstruction algorithm in the assessment of acute traumatic brain lesions in emergency non-enhanced computed tomography, in comparison with a standard hybrid iterative reconstruction approach. Materials and methods We retrospectively evaluated a total of 350 patients who underwent a 256-row non-enhanced computed tomography scan at the emergency department for brain trauma. Images were reconstructed both with hybrid and model-based iterative algorithm. Two radiologists, blinded to clinical data, recorded the presence, nature, number, and location of acute findings. Subjective image quality was performed using a 4-point scale. Objective image quality was determined by computing the signal-to-noise ratio and contrast-to-noise ratio. The agreement between the two readers was evaluated using k-statistics. Results A subjective image quality analysis using model-based iterative reconstruction gave a higher detection rate of acute trauma-related lesions in comparison to hybrid iterative reconstruction (extradural haematomas 116 vs. 68, subdural haemorrhages 162 vs. 98, subarachnoid haemorrhages 118 vs. 78, parenchymal haemorrhages 94 vs. 64, contusive lesions 36 vs. 28, diffuse axonal injuries 75 vs. 31; all P<0.001). Inter-observer agreement was moderate to excellent in evaluating all injuries (extradural haematomas k=0.79, subdural haemorrhages k=0.82, subarachnoid haemorrhages k=0.91, parenchymal haemorrhages k=0.98, contusive lesions k=0.88, diffuse axonal injuries k=0.70). Quantitatively, the mean standard deviation of the thalamus on model-based iterative reconstruction images was lower in comparison to hybrid iterative one (2.12 ± 0.92 vsa 3.52 ± 1.10; P=0.030) while the contrast-to-noise ratio and signal-to-noise ratio were significantly higher (contrast-to-noise ratio 3.06 ± 0.55 vs. 1.55 ± 0.68, signal-to-noise ratio 14.51 ± 1.78 vs. 8.62 ± 1.88; P<0.0001). Median subjective image quality values for model-based iterative reconstruction were significantly higher ( P=0.003). Conclusion Model-based iterative reconstruction, offering a higher image quality at a thinner slice, allowed the identification of a higher number of acute traumatic lesions than hybrid iterative reconstruction, with a significant reduction of noise.

scholarly journals A comparative study on image quality of two digital intraoral sensors

2019 ◽  
Vol 48 (7) ◽  
pp. 20190063 ◽  
Author(s):  
Cinar Aziman ◽  
Kristina Hellén-Halme ◽  
Xie-Qi Shi
Keyword(s):  
Image Quality ◽  
Observer Agreement ◽  
Visual Grading ◽  
Intra Class Correlation ◽  
Subjective Image Quality ◽  
Significant Difference ◽  
General Dentists ◽  
Parallel Technique ◽  
Specialist Group

Objectives The aims of this study were to evaluate the subjective image quality and reliability of two digital sensors. In addition, the image quality of the two sensors evaluated by specialists and general dentists were compared. Methods: 30 intraoral bitewings from five patients were included in the study, 15 were exposed with a Dixi sensor (CCD-based) and 15 with a ProSensor (CMOS-based) using modified parallel technique. Three radiologists and three general dentists evaluated the images in pair. A five-point scale was used to register the image quality. Visual grading characteristics (VGC) analysis was performed to compare the image quality and the observer agreement was assessed in terms of intra class correlation co-efficient. Results No statistically significant difference was found on image quality between the sensors. The average scores of the observer agreement were moderate with an average of 0.66 and an interval of 0.30 to 0.87, suggesting that there was a large variation on preference of image quality. However, there was a statistically significant difference in terms of the area under the VGC- curves between the specialist group and the general dentist group ( p = 0.043), in which the specialist group tended to favor the ProSensor. Conclusions Subjective image quality of the two intraoral sensors were comparable when evaluated by both general and oral radiologists. However, the radiologists seemed to prefer the ProSensor to the Dixi as compared to general dentists. Inter- observer conformance showed a large variation on the preference of the image quality.

scholarly journals Radiation dose and image quality of high-pitch emergency abdominal CT in obese patients using third-generation dual-source CT (DSCT)

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Robert Forbrig ◽  
Michael Ingrisch ◽  
Robert Stahl ◽  
Katharina Stella Winter ◽  
Maximilian Reiser ◽  
...  
Keyword(s):  
Image Quality ◽  
Radiation Dose ◽  
Third Generation ◽  
Obese Patients ◽  
Dual Source Ct ◽  
High Pitch ◽  
Subjective Image Quality ◽  
Dual Source ◽  
Group A

Abstract In this third-generation dual-source CT (DSCT) study, we retrospectively investigated radiation dose and image quality of portal-venous high-pitch emergency CT in 60 patients (28 female, mean age 56 years) with a body mass index (BMI) ≥ 30 kg/m2. Patients were dichotomized in groups A (median BMI 31.5 kg/m2; n = 33) and B (36.8 kg/m2; n = 27). Volumetric CT dose index (CTDIvol), size-specific dose estimate (SSDE), dose length product (DLP) and effective dose (ED) were assessed. Contrast-to-noise ratio (CNR) and dose-independent figure-of-merit (FOM) CNR were calculated. Subjective image quality was assessed using a five-point scale. Mean values of CTDIvol, SSDE as well as normalized DLP and ED were 7.6 ± 1.8 mGy, 8.0 ± 1.8 mGy, 304 ± 74 mGy * cm and 5.2 ± 1.3 mSv for group A, and 12.6 ± 3.7 mGy, 11.0 ± 2.6 mGy, 521 ± 157 mGy * cm and 8.9 ± 2.7 mSv for group B (p < 0.001). CNR of the liver and spleen as well as each calculated FOM CNR were significantly higher in group A (p < 0.001). Subjective image quality was good in both groups. In conclusion, third-generation abdominal high-pitch emergency DSCT yields good image quality in obese patients. Radiation dose increases in patients with a BMI > 36.8 kg/m2.

scholarly journals Third-generation dual-source computed tomography of the abdomen: comparison of radiation dose and image quality of 80kVp and 80/150kVp with tin filter

2020 ◽  
Author(s):  
Seung Joon Choi ◽  
So Hyun Park ◽  
Seong Ho Park ◽  
Seong Yong Pak ◽  
Jae Won Choi ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Image Quality ◽  
Radiation Dose ◽  
Third Generation ◽  
Line Density ◽  
Oncology Patients ◽  
Subjective Image Quality ◽  
Dual Source ◽  
Lesion Conspicuity ◽  
Tin Filter

AbstractObjectiveTo compare the radiation dose, objective and subjective image quality, and diagnostic performances of 80 kVp and 80/150 kVp with tin filter (80/Sn150 kVp) computed tomography (CT) in oncology patients.MethodsOne hundred forty-five consecutive oncology patients who underwent third-generation dual-source dual-energy CT of the abdomen for evaluation of malignant visceral, peritoneal, extraperitoneal, and bone tumor were retrospectively recruited. Two radiologists independently reviewed each observation in 80 kVp CT and 80/Sn150 kVp CT. Modified line-density profile of the tumor and contrast-to-noise ratio (CNR) were measured. Diagnostic confidence, lesion conspicuity, and subjective image quality were calculated and compared between image sets.ResultsModified line-density profile analysis revealed higher attenuation differences between the tumor and the normal tissue in 80 kVp CT than in 80/Sn150 kVp CT (127 vs. 107, P = 0.05). The 80 kVp CT showed increased CNR in the liver (8.0 vs. 7.6) and the aorta (18.9 vs. 16.3) than the 80/Sn150 kVp CT. The 80 kVp CT yielded higher enhancement of organs (4.9 ± 0.2 vs. 4.7 ± 0.4, P < 0.001) and lesion conspicuity (4.9 ± 0.3 vs. 4.8 ± 0.5, P = 0.035) than the 80/Sn150 kVp CT; overall image quality and confidence index were comparable. The effective dose reduced by 45.2% with 80 kVp CT (2.3 mSv ± 0.9) compared to 80/Sn150 kVp CT (4.1 mSv ± 1.5).ConclusionsThe 80 kVp CT performed similar or better than 80/Sn150 kVp CT for abdominal tumor evaluation with 45.2% radiation dose reduction in oncology patients.

Abstract 690: Variability and Predictors of Patient Radiation Dose with Dual Source Cardiac CT: Implications for Future Algorithms to Reduce Patient Radiation Dose

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Ron Blankstein ◽  
Rodrigo Pale ◽  
Khurram Nasir ◽  
Amar B Shah ◽  
Hiram Bezerra ◽  
...  
Keyword(s):  
Image Quality ◽  
Radiation Dose ◽  
Radiation Exposure ◽  
Medical Center ◽  
Pulmonary Veins ◽  
Wide Range ◽  
Significant Difference ◽  
Patient Radiation Exposure ◽  
Patient Radiation Dose ◽  
Scan Length

Intro : DSCT provides improved temporal resolution due to the simultaneous use of two x-ray sources & detectors. Although use of two sources may increase radiation, the DSCT offers key mechanisms to reduce dose (i.e. pitch adaptation, tube current modulation (TCM) & prospective triggering). Thus, our aim was to assess the patient radiation exposure associated with DSCT and identify variations based on the use of different scan related parameters. Methods : Prospective study of a single tertiary medical center where radiation and image quality related data was collected on 304 consecutive patients (pts) presenting for clinical CCT examination. Effective radiation dose was calculated by multiplying the dose-length product × (k=.017 mSv/mGy/cm). Image quality was rated on a subjective IQ score [1=poor to 4=excellent], as well as contrast (CNR) and signal-to-noise (SNR) ratios. Adjusted means of increased radiation dose were calculated based on linear regression models. Results: Among 304 consecutive studies (mean age 56.4, BMI 29.4 kg/m 2 , 37% Female), 60% were performed for coronary evaluation, 8% for CABG, 18% for pulmonary veins and 11% for aortic disease. The average radiation dose was 13.5±9.2mSv [range 0.5–55.5 mSv]. TABLE provides unadjusted and adjusted mean radiation dose for parameters which had a significant univariate association with radiation dose. Independent predictors of lower radiation included low kV, use of TCM, higher pitch, smaller scan length, and regular heart rhythm. Selected use of various TCM algorithms & low KV resulted in no significant difference in IQ, CNR, or SNR. Conclusions : DSCT is associated with a wide range of patient radiation exposure. The variability in dose is due to both controllable parameters (i.e. use of TCM, low kV, scan length) as well as parameters that cannot be altered (i.e. irregular rhythm). These results suggest that individualizing scan protocols may result in lower radiation dose without compromising image quality. Table: Cardiac DSCT Parameters Affecting Patient Radiation Dose

scholarly journals Transradial approach for diagnostic cerebral angiograms in the elderly: a comparative observational study

2020 ◽  
pp. neurintsurg-2020-016140
Author(s):  
Ahmad Sweid ◽  
Somnath Das ◽  
Joshua H Weinberg ◽  
Kareem E l Naamani ◽  
Julie Kim ◽  
...  
Keyword(s):  
Comparative Analysis ◽  
Elderly Patients ◽  
Radiation Exposure ◽  
The Elderly ◽  
Fluoroscopy Time ◽  
Access Site ◽  
Transradial Approach ◽  
Contrast Dose ◽  
Significant Difference ◽  
Procedure Duration

BackgroundThe transradial approach (TRA) reduces mortality, morbidity, access site complications, hospital cost, and length of stay while maximizing patient satisfaction. We aimed to assess the technical success and safety of TRA for elderly patients (aged ≥75 years).MethodsA retrospective chart review and comparative analysis was performed for elderly patients undergoing a diagnostic cerebral angiogram performed via TRA versus transfemoral approach (TFA). Also, a second comparative analysis was performed among the TRA cohort between elderly patients and their younger counterparts.ResultsComparative analysis in the elderly (TRA vs TFA) showed no significant differences for contrast dose per vessel (43.7 vs 34.6 mL, P=0.106), fluoroscopy time per vessel (5.7 vs 5.2 min, P=0.849), procedure duration (59.8 vs 65.2 min, P=0.057), conversion rate (5.8% vs 2.9%, P=0.650), and access site complications (2.3% vs 2.9%, P=1.00). Radiation exposure per vessel (18.9 vs 51.9 Gy cm2, P=0.001) was significantly lower in the elderly TRA group.The second comparison (TRA in elderly vs TRA in the young) showed no significant differences for contrast dose per vessel (43.7 vs 37.8 mL, P=0.185), radiation exposure per vessel (18.9 vs 16.5 Gy cm2, P=0.507), procedure duration (59.8 vs 58.3 min, P=0.788), access site complication (2.3% vs 1.7%, P=0.55), and conversation rate (5.8% vs 1.8%, P=0.092). A trend for prolonged fluoroscopy time per vessel (5.7 vs 4.7 min, P=0.050) was observed in the elderly TRA group.ConclusionsTRA is a technically feasible and safe option for diagnostic neurointerventional procedures in the elderly. Our small elderly cohort was not powered enough to show a significant difference in terms of access site complications between TRA and TFA.

scholarly journals Diagnostic Performance of Different Simulated Low-Dose Levels in Patients with Suspected Cervical Abscess Using a Third-Generation Dual-Source CT Scanner

Diagnostics ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1072
Author(s):  
Moritz T. Winkelmann ◽  
Saif Afat ◽  
Sven S. Walter ◽  
Eva Stock ◽  
Vincent Schwarze ◽  
...  
Keyword(s):  
Image Quality ◽  
Diagnostic Accuracy ◽  
Iterative Reconstruction ◽  
Low Dose ◽  
Sternocleidomastoid Muscle ◽  
Third Generation ◽  
Dual Source Ct ◽  
Diagnostic Confidence ◽  
Subjective Image Quality ◽  
Dual Source

The aim of this study was to investigate the effects of dose reduction on diagnostic accuracy and image quality of cervical computed tomography (CT) in patients with suspected cervical abscess. Forty-eight patients (mean age 45.5 years) received a CT for suspected cervical abscess. Low-dose CT (LDCT) datasets with 25%, 50%, and 75% of the original dose were generated with a realistic simulation. The image data were reconstructed with filtered back projection (FBP) and with advanced modeled iterative reconstruction (ADMIRE) (strengths 3 and 5). A five-point Likert scale was used to assess subjective image quality and diagnostic confidence. The signal-to-noise ratio (SNR) of the sternocleidomastoid muscle and submandibular gland and the contrast-to-noise ratio (CNR) of the sternocleidomastoid muscle and submandibular glandular fat were calculated to assess the objective image quality. Diagnostic accuracy was calculated for LDCT using the original dose as the reference standard. The prevalence of cervical abscesses was high (72.9%) in the cohort; the mean effective dose for all 48 scans was 1.8 ± 0.8 mSv. Sternocleidomastoid and submandibular SNR and sternocleidomastoid muscle fat and submandibular gland fat CNR increased with higher doses and were significantly higher for ADMIRE compared to FBP, with the best results in ADMIRE 5 (all p < 0.001). Subjective image quality was highest for ADMIRE 5 at 75% and lowest for FBP at 25% of the original dose (p < 0.001). Diagnostic confidence was highest for ADMIRE 5 at 75% and lowest for FBP at 25% (p < 0.001). Patient-based diagnostic accuracy was high for all LDCT datasets, down to 25% for ADMIRE 3 and 5 (sensitivity: 100%; specificity: 100%) and lower for FBP at 25% dose reduction (sensitivity: 88.6–94.3%; specificity: 92.3–100%). The use of a modern dual-source CT of the third generation and iterative reconstruction allows a reduction in the radiation dose to 25% (0.5 mSv) of the original dose with the same diagnostic accuracy for the assessment of neck abscesses.

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