Multi-slice spiral CT has been an outstanding progress in developmental history of CT technology. The technical indexes of all three respects, ie scanning range time and spatial resolution are all marked improved. And several robust post-processing techniques have been imported into CT data post-scanning reconstruction, which help massive volume data being sufficiently and optimally interpreted. Therefore, newer advances have been achieved both in clinical applications and diagnostic efficacy.
Tomography, Spiral Computed ; methods

OBJECTIVE: To build a helical CT projection data restoration model at random low-dose levels. METHODS: We used a noise estimation module to achieve noise estimation and obtained a low-dose projection noise variance map, which was used to guide projection data recovery by the projection data restoration module. A filtering back-projection algorithm (FBP) was finally used to reconstruct the images. The 3D wavelet group residual dense network (3DWGRDN) was adopted to build the network architecture of the noise estimation and projection data restoration module using asymmetric loss and total variational regularization. For validation of the model, 1/10 and 1/15 of normal dose helical CT images were restored using the proposed model and 3 other restoration models (IRLNet, REDCNN and MWResNet), and the results were visually and quantitatively compared. RESULTS: Quantitative comparisons of the restored images showed that the proposed helical CT projection data restoration model increased the structural similarity index by 5.79% to 17.46% compared with the other restoration algorithms (P < 0.05). The image quality scores of the proposed method rated by clinical radiologists ranged from 7.19% to 17.38%, significantly higher than the other restoration algorithms (P < 0.05). CONCLUSION The proposed method can effectively suppress noises and reduce artifacts in the projection data at different low-dose levels while preserving the integrity of the edges and fine details of the reconstructed CT images.
Algorithms ; Artifacts ; Tomography, Spiral Computed ; Tomography, X-Ray Computed/methods*

Computed tomography angiography (CTA) is a useful approach for diagnosing vascular diseases. In this paper, we proposed a reconstruction algorithm for dual-source spiral CT with variable pitch. The projection data are collected by the double-source double-multislice spiral CT (DSDMS-CT). However, the pitch of the DSDMS-CT is variable other than being constant. We have developed a new formula performing interpolation along Z-axis for dual-source spiral CT with variable pitch. The dual-source spiral CT with variable pitch can chase contrast bolus more flexibly and more effectively. The simulation results show the correctness and efficiency of the proposed algorithm.
Algorithms ; Coronary Angiography ; methods ; Humans ; Tomography, Spiral Computed ; instrumentation ; methods

The upper slicing system is the main components of the optical system in MSCT. This paper focuses on the design of upper slicing system and its accuracy analysis to improve the accuracy of imaging. The error of slice thickness and ray center by bearings, screw and control system were analyzed and tested. In fact, the accumulated error measured is less than 1 microm, absolute error measured is less than 10 microm. Improving the accuracy of the upper slicing system contributes to the appropriate treatment methods and success rate of treatment.
Computer Simulation ; Equipment Design ; Tomography, Spiral Computed ; instrumentation ; methods

OBJECTIVETo implement dose reconstruction and dose-guided intensity modulated radiotherapy for helical tomotherapy.

METHODSDose reconstruction was implemented on adaptive helical tomotherapy with the online megavoltage CT (MVCT) imaging from a patient with nasopharyngeal cancer. The differences of isodose line between actual and planned deposition were analysis in 3D distribution, on which the hot spot and cold spot were lined. The dose delivered to these areas was modulated in later fractions to keep the planned requirement.

RESULTSThe differences between actual and planned isodose line were shown on the image visually. The modulation to the hot spot and cold spot in later fraction corrected the incorrectly delivered dose to achieve the requirement of primary plan.

CONCLUSIONSThe dose reconstruction and dose-guided intensity modulated radiotherapy can be implemented in adaptive helical tomotherapy.

Humans ; Radiotherapy Dosage ; Radiotherapy Planning, Computer-Assisted ; methods ; Radiotherapy, Intensity-Modulated ; methods ; Tomography, Spiral Computed ; methods

OBJECTIVETo evaluate the value of double source multidetector computed tomography (MDCT) in visualization of cardiac veins in patients with chronic heart failure.

METHODSThirty-five patients with chronic heart failure (aged 65.4 ± 8.8, 21 males and 14 females) were enrolled in the study. In Group A, MDCT and retrograde coronary venography (RCV) were performed consecutively; in Group B anterograde visualization of the coronary venous and RCV were performed.

RESULTSCoronary sinus, GCV and MCV of all individuals were identified in MDCT. LVPV was observed in 65% patients of Group A, and 66.7% patients of Group B. The correlation coefficient between MDCT and RCV was 0.944, and that between CVG and RCV was 0.42.

CONCLUSIONNon-invasive evaluation of cardiac veins with double source CT is feasible and may be used in cardiac resynchronization therapy.

Aged ; Coronary Angiography ; methods ; Female ; Humans ; Male ; Middle Aged ; Phlebography ; methods ; Tomography, Spiral Computed ; methods

To improve the part of the hardware about Xin Hua SL-IC model X-ray radiotherapy simulative position finder, using CR and PACS, so that located-picture shooting for the simulative position finder have been realized digital upgrade.
Automatic Data Processing ; Radiographic Image Enhancement ; Radiotherapy ; methods ; Tomography, Spiral Computed ; methods

Although selective coronary angiography is a golden standard for diagnosing coronary artery diseases, it is expensive and may cause a little danger to the patient. With the advancement of space-resolution, time-resolution and various kinds of scan techniques, the sectional image methods such as electron beam CT, multislice spiral CT and magnetic resonance imaging will be prospective non-invasive techniques to diagnose coronary artery and other heart diseases.
Coronary Artery Disease ; diagnosis ; diagnostic imaging ; Electrons ; Humans ; Magnetic Resonance Imaging ; methods ; Tomography ; methods ; Tomography, Spiral Computed ; methods ; Ultrasonography

The emergence of multi-slice spiral computed tomography (MSCT) has a significant influence on cardiovascular imaging. As a noninvasive technique, MSCT is considered suitable for the evaluation of coronary artery stenosis, quantitative and qualitative assessment of plaque, analysis of cardiac function and myocardial perfusion imaging, and determination of the patency of stents or bypass grafts. Recent studies has shown that noninvasive coronary artery imaging with MSCT is a feasible screening test for suspected coronary artery diseases and a valuable follow-up tool for patients who have undergone interventional or surgical therapeutic procedures.
Coronary Angiography ; methods ; Coronary Artery Disease ; diagnostic imaging ; Coronary Stenosis ; diagnostic imaging ; Humans ; Tomography, Spiral Computed

Adult ; Humans ; Male ; Middle Aged ; Pneumoconiosis ; diagnostic imaging ; Radiography, Thoracic ; methods ; Tomography, Spiral Computed