A preliminary evaluation study of applying a deep learning image reconstruction algorithm in low-kilovolt scanning of upper abdomen

Author(s):  
Ya-Ning Wang ◽  
Yu Du ◽  
Gao-Feng Shi ◽  
Qi Wang ◽  
Ru-Xun Li ◽  
...  

OBJECTIVE: To investigate feasibility of applying deep learning image reconstruction (DLIR) algorithm in a low-kilovolt enhanced scan of the upper abdomen. METHODS: A total of 64 patients (BMI<28) are selected for the enhanced upper abdomen scan and divided evenly into two groups. The tube voltages in Group A are 100kV in arterial phase and 80kV in venous phase, while tube voltages are 120kV during two phases in Group B. Image reconstruction algorithms used in Group A include the filtered back projection (FBP) algorithm, the adaptive statistical iterative reconstruction-Veo (ASIR-V 40% and 80%) algorithm, and the DLIR algorithm (DL-L, DL-M, DL-H). Image reconstruction algorithm used in Group B is ASIR-V40%. The different reconstruction algorithm images are used to measure the common hepatic artery, liver, renal cortex, erector spinae, and subcutaneous adipose in the arterial phase and the average CT value and standard deviation of the portal vein, liver, spleen, erector spinae, and subcutaneous adipose in the portal phase. The signal-to-noise ratio (SNR) is calculated, and the images are also scored subjectively. RESULTS: In Group A, noise in the aorta, liver, portal vein (the portal phase), spleen (the portal phase), renal cortex, retroperitoneal adipose, and muscle is significantly lower in both the DL-H and ASIR-V80% images, and the SNR is significantly higher than those in the remaining groups (P<0.05). The SNR of each tissue and organ in Group B is not significantly different from that in DL-M, DL-L, and ASIR-V40% in Group A (P>0.05). The subjective image quality scores in the DL-H and B groups are higher than those in the other groups, and the FBP group has significantly lower image quality than the remaining groups (P<0.05). CONCLUSION: For upper abdominal low-kilovolt enhanced scan data, the DLIR-H gear yields a more satisfactory image quality than the FBP and ASIR-V.

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Chen J ◽  
◽  
Li M ◽  
Gao Z ◽  
Liu S ◽  
...  

Aim: This study was designed to investigate the application of whole-body low-dose computed tomography in the examination of multiple myeloma. Method: 40 patients with multiple myeloma admitted to our hospital were prospectively selected as the study subjects. All patients were pathologically confirmed and/or clinically diagnosed with multiple myeloma. Patients were randomly divided into two groups: Group A (n=20) received whole-body lowdose CT scan with SAFIR iterative reconstruction algorithm; Group B (n=20) underwent whole body conventional dose CT scan combined with conventional reconstruction algorithm. The image quality was scored subjectively, and the objective evaluation indexes (including CT value and noise of neck, chest, abdomen, pelvic cavity and lower extremities, signal-to-noise ratio and image quality index) were measured and recorded, and the radiation dose was recorded. Mann-Whitney U test (to evaluate the subjective score) and t test (to evaluate the objective evaluation index and radiation dose) were used to compare the differences of the above indexes between group A and group B. Result: All the images met the diagnostic requirements. There was no statistical significance in the scores between group A and group B (P>0.05). Significant differences in CT value, noise and SNR of neck, chest, abdomen, pelvis and lower extremities between group A and group B (P<0.05) were identified. For the image quality index (figure of merit, FOM), the FOM of chest, abdomen and pelvis was not statistically significantly changed (P<0.05). The radiation dose of group A decreased by 56.77% (3.06/5.39) compared to group B with a statistically significant difference (P<0.05). The Kappa values of subjective scores of the two groups showed no statistically significant difference (respectively, 0.68 and o.69, P>0.05). Conclusion: Compared to conventional CT examination, whole-body lowdose CT scan combined with SAFIR iterative reconstruction algorithm can effectively reduce noise, reduce X-ray radiation dose, and obtain ideal image quality in multiple myeloma examination, which has a certain application value.


2019 ◽  
Author(s):  
Noor Ruhaya Ibrahim ◽  
Noor Khairiah A. Karim ◽  
Ibrahim Lutfi Shuaib ◽  
Noor Diyana Osman ◽  
Salwah Hashim ◽  
...  

Abstract Objective The aim of this study is to compare the effect of different contrast administration protocols practiced in Advanced Medical and Dental Institute, Universiti Sains Malaysia (Group A) and Hospital Pulau Pinang, Malaysia (Group B), on contrast enhancement and image quality in computed tomography scan. The two protocols were fixed time delay (FTD) with fixed volume (FV), and automatic bolus tracking (ABT) with weight based volume (WBV) contrast administration. Quantification of contrast enhancement’s magnitude in four different anatomical structures was measured in Hounsfield Unit (HU) and based on 5-point scale (1=poor, 5=excellent), the images were rated qualitatively.Results Mean enhancement values of all structures in Group B was higher compared to Group A (p = < 0.001). Mean of quality rating between the two groups was statistically not significant (p = 0.185). There was a weak correlation between HU values and administered contrast volume (r = 0.152). It can be concluded that FTD with FV protocol is non inferior to ABT with WBV protocol as it yielded higher degree of contrast enhancement. There was no significant difference between the two protocols in term of qualitative assessment although ABT with WBV protocol had higher mean grading in image quality.


2019 ◽  
Vol 61 (1) ◽  
Author(s):  
Christin Röttiger ◽  
Maren Hellige ◽  
Bernhard Ohnesorge ◽  
Astrid Bienert-Zeit

Abstract Background The use of cadavers for radiology research methodologies involving subjective image quality evaluation of anatomical criteria is well-documented. The purpose of this method comparison study was to evaluate the image quality of dental and adjacent structures in computed tomography (CT) and high-field (3 T) magnetic resonance (MR) images in cadaveric heads, based on an objective four-point rating scale. Whilst CT is a well-established technique, MR imaging (MRI) is rarely used for equine dental diagnostics. The use of a grading system in this study allowed an objective assessment of CT and MRI advantages in portraying equine cheek teeth. As imaging is commonly performed with cadaveric or frozen and thawed heads for dental research investigations, the second objective was to quantify the impact of the specimens’ conditions (in vivo, post-mortem, frozen-thawed) on the image quality in CT and MRI. Results The CT and MR images of nine horses, focused on the maxillary premolar 08s and molar 09s, were acquired post-mortem (Group A). Three observers scored the dental and adjacent tissues. Results showed that MR sequences gave an excellent depiction of endo- and periodontal structures, whereas CT produced high-quality images of the hard tooth and bony tissues. Additional CT and MRI was performed in vivo (Group B) and frozen-thawed (Group C) in three of these nine horses to specify the condition of the best specimens for further research. Assessing the impact of the specimens’ conditions on image quality, specific soft tissues of the maxillary 08s and 09s including adjacent structures (pulps, mucosa of the maxillary sinuses, periodontal ligament, soft tissue inside the infraorbital canal) were graded in group B and C and analysed for significant differences within CT and MR modalities in comparison to group A. Results showed that MRI scores in vivo were superior to the post-mortem and frozen-thawed condition. Conclusions On comparing the imaging performance of CT and MRI, both techniques show a huge potential for application in equine dentistry. Further studies are needed to assess the clinical suitability of MRI. For further research investigations it must be considered, that the best MR image quality is provided in live horses.


2020 ◽  
pp. 028418512091762
Author(s):  
Ting Liang ◽  
Yonghao Du ◽  
Chenguang Guo ◽  
Yuan Wang ◽  
Jin Shang ◽  
...  

Background Computed tomography (CT)-guided percutaneous lung biopsy is usually performed by helical scanning. However, there are no studies on radiation dose, diagnostic accuracy, image quality, and complications based on axial scan mode. Purpose To determine radiation dose, accuracy, image quality, and complication rate following an ultra-low-dose (ULD) protocol for CT-guided lung biopsy in clinic. Material and Methods A total of 105 patients were enrolled to receive CT-guided lung biopsy. The use of an ULD protocol (axial scan) for CT-guided biopsy was initiated. Patients were randomly assigned to axial mode (Group A) and conventional helical mode (Group B) CT groups. 64-slice CT was performed for CT-guided pulmonary biopsy with an 18-G coaxial cutting biopsy needle. The radiation dose, accuracy, image quality, and complication rate were measured. Results Ninety-seven patients were selected for the final phase of the study. There was no significant difference between the two groups for pulmonary nodule characteristics ( P > 0.05). The mean effective dose in group A (0.077 ± 0.010 mSv) was significantly reduced relative to group B (0.653 ± 0.177 mSv, P < 0.001). There was no significant difference in accuracy, image quality, and complication rate ( P > 0.050) between the two modes. Conclusion An ULD protocol for CT-guided lung nodule biopsy yields a reduction in the radiation dose without significant change in the accuracy, image quality, and complication rate relative to the conventional helical mode scan.


2017 ◽  
Vol 59 (5) ◽  
pp. 546-552 ◽  
Author(s):  
Yeo-Jin Jeong ◽  
Ki Seok Choo ◽  
Kyung Jin Nam ◽  
Ji Won Lee ◽  
Jin You Kim ◽  
...  

Background Computed tomography venography (CTV) at low kVp using model-based iterative reconstruction (MBIR) can enhance vascular enhancement with noise reduction. Purpose To evaluate image qualities and radiation doses of CTV at 80 kVp using MBIR and a small iodine contrast media (CM) dose and to compare these with those of CTV performed using a conventional protocol. Material and Methods Sixty-five patients (mean age = 58.1 ± 7.2 years) that underwent CTV for the evaluation of deep vein thrombosis (DVT) and varicose veins were enrolled in this study. Patients were divided into two groups: Group A (35 patients, 80 kVp, MBIR, automatic tube current modulation, CM = 270 mg/mL, 100 mL) and Group B (30 patients, 100 kVp, filtered back projection [FBP], 120 fixed mA, CM = 370 mg/mL, 120 mL). Objective and subjective image qualities of inferior vena cava (IVC), femoral vein (FV), and popliteal vein (PV) were assessed and radiation doses were recorded. Results Mean vascular enhancement in group A was significantly lower than in group B ( P < 0.01). Noise in group A was significantly lower than in group B except for PV and contrast-to-noise ratio were not significantly different in the two groups ( P > 0.05). In addition, radiation dose in group A was significantly lower than in group B ( P < 0.001). Subjective image quality comparison revealed group A was statistically inferior to group B except for subjective image noise. Conclusion CTV at 80 kVp using MBIR with small iodine contrast dose provided acceptable image quality at a lower radiation dose than conventional CTV using FBP.


2021 ◽  
Author(s):  
Dae-Myoung (Danny) Yang

Ultrasound imaging based on transmitting plane waves (PW) enables ultrafast imaging. Coherent PW compounding ultrasound imaging can reach the image quality of optimal multifocus image. In the image reconstruction, it was assumed that an infinite extent PWs was emitted. In this thesis, we propose a new image reconstruction algorithm – Synthetic-aperture plane-wave (SAPW) imaging – without using this assumption. The SAPW imaging was compared with the PWs imaging in numerical simulations and experimental measurements. The measured RF data in PW imaging was first decoded in the frequency domain using a pseudoinverse algorithm to estimate the RF data Then, SAPW RF data were used to reconstruct images through the standard synthetic transit aperture (STA) method. Main improvements in the image quality of the SAPW imaging in comparison with the PWs imaging are increases in the depth of penetration and the field of view when contrast-to-noise ratio (CNR) was used as a quantitative metric.


2019 ◽  
Vol 61 (1) ◽  
pp. 28-36
Author(s):  
Zlatan Alagic ◽  
Haris Alagic ◽  
Robert Bujila ◽  
Subhash Srivastava ◽  
Saif Jasim ◽  
...  

Background The use of computed tomography (CT) for image guidance during biopsies is a powerful approach. The method is, however, often associated with a significant level of radiation exposure to the patient and operator. Purpose To investigate if a low-dose protocol for CT-guided musculoskeletal (MSK) biopsies, including a combination of different radiation dose (RD) techniques, is feasible in a clinical setting. Material and Methods Fifty-seven patients underwent CT-guided fine-needle aspiration cytology (FNAC) utilizing the low-dose protocol (group A). A similar number of patients underwent CT-guided FNAC using the reference protocol (group B). Between-group comparisons comprised radiation dose, success rate, image quality parameters, and workflow. Results In group A, the mean total dose-length product (DLP) was 41.2 ± 2.9 mGy*cm, which was statistically significantly lower than of group B (257.4 ± 22.0 mGy*cm), corresponding to a mean dose reduction of 84% ( P<0.001). The mean CTDIvol for the control scans were 1.88 ± 0.09 mGy and 13.16 ± 0.40 mGy for groups A and B, respectively ( P < 0.001). The success rate in group A was 91.2% and 87.9% in group B ( P = 0.56). No negative effect on image-quality parameters, time of FNAC, and number of control scans were found. Conclusion We successfully developed a low-dose protocol for CT-guided MSK biopsies that maintains diagnostic accuracy and image quality at a fraction of the RD compared to the reference biopsy protocol at our clinic.


Author(s):  
Lifeng Wang ◽  
Xingxing Jin ◽  
Zhenguo Qiao ◽  
Bin Xu ◽  
Jiaqing Shen

Objectives: This study investigated the radiation dose and value of prospective dualenergy computed tomography (DECT) in the diagnosis of gastric cancer. Methods: Sixty patients scheduled for computed tomography (CT) for preoperative staging were divided into two groups. Thirty patients (Group A) underwent a single contrast-enhanced abdominal CT acquisition using a dual-source mode (100 kV/140 kV). Weighted average images of the two-kilovolt acquisitions and iodine maps were created. The remaining 30 patients underwent a standard CT scan (Group B). Two observers performed a blinded read of the images for gastric lesions, evaluating the image quality and recording effective dose. Results: During the blinded read, observers found 90% (27/30) of the cancers in both groups. The mean imaging quality scores were 2.1±0.9 for Group A, and 2.3±1.1 for Group B. The effective mean doses were 6.59±0.59 mSv and 25.86±0.44 mSv for Groups A and B, respectively. Compared with the control group (B), the imaging quality in the low-dose group decreased a little, but the radiation dose substantially decreased by 74.6%. Conclusion: The new DECT technique is valuable for examining gastric cancer patients. The dualkV scan mode can substantially reduce radiation dose while preserving good diagnostic image quality.


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