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雙源CT診斷肺動脈吊帶畸形一例

迭代重建技術降低踝關節內固定金屬偽影的價值

目的 探討迭代重建（iterative reconstruction，IR）技術在踝關節金屬內固定術后數字化斷層融合（digital radiographic tomosynthesis，DTS）檢查中的臨床應用價值。 方法 2014 年 10 月—2015 年 6 月采用 DTS 技術檢查踝關節金屬內固定術后復查患者 30 例，每例患者的原始數據分別采用 IR 算法和濾波反投影（filter back projection，FBP）算法進行重建。重建后圖像根據圖像噪聲、內固定金屬周圍骨質清晰度和失真度，以 3 分法對圖像質量進行主觀評價，數值越高圖像越清晰；測量螺釘偽影長度、螺釘與骨質結合程度作為客觀數據評價，數據值越小圖像質量越好。 結果 圖像噪聲、內固定周圍骨質清晰度和失真度的主觀評分：采用 IR 算法重建的圖像中，優片 26 例（86.7%），良片 4 例（13.0%）；采用 FBP 算法重建的圖像中，優片 3 例（10.0%），良片 27 例（90.0%）；兩種算法重建圖像優質率差異有統計學意義（χ2=21.043，P<0.001）。兩種算法重建圖像均無螺釘偽影。IR 算法重建圖像螺釘與骨質結合緊密，間隙度為 0 mm；FBP 算法重建圖像螺釘與骨質結合間隙度為 0.2～0.3 mm，系金屬硬化束偽影。 結論 DTS 掃描 IR 技術能有效降低踝關節內固定金屬偽影，圖像質量明顯優于 FBP 重建圖像，踝關節金屬內固定 DTS 檢查 IR 技術有較高的臨床應用價值。

The Application of 70 kV and Sonogram-affirmed Iterative Reconstruction Technique in CT Examination for Children with Congenital Heart Disease

ObjectiveTo evaluate the value of 70 kV and sonogram-affirmed iterative reconstruction technique in CT examination for children with congenital heart disease. MethodsThirty children with congenital heart disease who underwent CT scan between January and September 2014 were included in this study. According to the different tube voltage, they were randomly divided into group A (80 kV) and group B (70 kV), with fifteen in each. All the children were scanned on a dual-source-CT (Siemens Definition Flash). Group A used filtered back projection reconstruction. Group B used sonogram-affirmed iterative reconstruction. We measured and calculated the pulmonary artery signal-to-noise ratio at the level of main pulmonary artery window, the signal-to-noise ratio of the ascending aorta, noise ratio contrast between the pulmonary artery and erector spinae and between the ascending aorta and erector spinae. The image quality for congenital heart disease was assessed by two senior radiologists. The measurement of radiation dose included effective dose (ED), volume CT dose index (CTDIvol) and dose length product (DLP). ResultsThere were no significant differences between group A and B in terms of pulmonary artery signal-to-noise ratio (14.54±3.77, 11.23±2.52), the signal-to-noise ratio of the ascending aorta (14.76±3.41, 12.31±3.47), the noise ratio contrast between pulmonary artery and erector spinae (12.04±3.96, 9.18±3.76) and between the ascending aorta and erector spinae (12.47±4.59, 9.77±4.41) (P > 0.05). There was significant difference between group A and group B in CTDIvol[(0.53±0.09), (0.38±0.03) mGy], DLP[(12.93±1.79), (6.67±0.72) mGy·cm], and ED[(0.34±0.05), (0.17±0.02) mSv] (P < 0.05). ConclusionThe application of 70 kV and sonogram-affirmed iterative reconstruction technique in CT examination for children with congenital heart disease can significantly reduce the radiation dose without any influence on image quality.

Influence of the abduction angle of the double upper limbs on liver non-enhanced CT image quality in patients with vehicle accident

ObjectivesTo investigate the influence of the abduction angle of the upper extremities on the image quality of non-enhanced CT scan and clinical value of the patients who cannot lift with double upper limbs by vehicle accident.Methods60 patients with double upper limbs that could not lift by vehicle accidents were required to receive liver non-enhanced CT scan, the patients were divided into 3 groups according to the abduction angle (group A, B, C), 20 cases in each group, another 20 cases with standard pose as the control group (group D). The CT value and standard deviation of the liver region of interest, the erector and the background air were measured, and the contrast to noise ratio of liver images, image noise value were calculated, together with the assessment of image quality and statistic analysis.ResultsThe liver non-enhanced CT scan were completed successfully. The image quality of group D was significantly better than A, B, C (Z=–10.753, P<0.05;Z=–11.645, P<0.05;Z=–12.281, P<0.05), respectively. Group C was better than A and B (Z=–8.502, P<0.05;Z=–4.068, P<0.05), respectively. Group B was better than A (Z=–5.885, P<0.05). The CNR of the four groups of images increased gradually, group A (0.09±0.77), group B (1.56±0.83), group C (2.51±0.87), group D (2.59±0.97), respectively. There were significant differences between four groups (F=36.323, P<0.05). The image noise decreased systematically, group A (14.84±2.94), group B (13.04±1.59), group C (11.60±1.72), group D (10.44±1.13), respectively. There were significant differences between four groups (H=426.755, P<0.05).ConclusionOn the premise of safety inspection, with the enlargement of angle of the upper limbs of patients who cannot lift with double upper limbs by vehicle accidents, the image noise decreased and image quality is improved with the increase of signal noise ratio.

Study on the Feasibility of Brain CT Perfusion with 70 kV Tube Voltage

ObjectiveTo investigate the influence of 70 kV low-dose CT perfusion technique on brain CT perfusion parameter maps and image quality. MethodsRetrospective analysis of all patients who underwent CT perfusion of brain between October 2013 and February 2014 was carried out. The patients were randomly divided into two groups according to diTherent CT examination dose: group A (80 kV, 200 mAs) and group B (70 kV, 200 mAs). All patients were scanned on a dual-source-CT (Siemens Definition Flash). Fifteen normal subjects without brain diseases in each group were selected to be studied. Region of interest (ROI) with an area of 80 mm2 was placed in the nucleus, putamen, thalamus, periventricular white matter of the frontal lobe and temporo-occipital area, and the parameters in the ROI including cerebral blood flow, cerebral blood volume, mean transit time and time to peak were detected. The carrierto-noise ratio and signal-to-noise ratio of thalamus and periventricular white matter of the frontal lobe were contrasted. The image quality of perfusion was assessed by two senior radiologists using 5 point system for blind assessment (5=best, 1=worst). The measurement of radiation dose was studied through effective dose, volume CT dose index (CTDIVOL) and dose length product (DLP). Statistical analysis was performed by independent sample t test. ResultsThere was no significant difference between group A and group B in brain CT perfusion parameters (P>0.05). There was no significant diTherence in image quality between the two groups in the objective and subjective assessment (P>0.05). In comparison with group A, the measured effective dose, CTDIVOL and DLP for group B decreased by 35%. ConclusionThere was no significant influence on the brain CT perfusion parameters and image quality using 70 kV tube voltage, and radiation dose is decreased obviously.

Value of Multi-slice CT in Assessing the Features of Carotid Artery Plaques

目的　探討多層螺旋CT在評價頸動脈斑塊特征中的價值。 方法　回顧性分析2011年7月－10月132例行CT頸部血管造影患者的影像資料。對頸動脈斑塊特征進行評價，重建方法包括多層面重建、容積再現技術、最大密度投影及曲面重建。 結果　132例患者中，80例檢出頸動脈斑塊，最常出現鈣化斑塊的部位為海綿竇段和床突上段，右側海綿竇段52例（65.0%）、左側海綿竇段49例（61.3%），右床突上段37例（46.3%）、左側床突上段30例（37.5%）。最常出現軟斑塊的部位為雙側頸總動脈，均為12例（15.0%）。最常出現混合斑塊的部位為頸總動脈，右側頸總動脈9例（11.3%）、左側頸總動脈12例（15.0%）。頸動脈最容易輕度狹窄294處（294/1 440，20.4%），中、重度狹窄少見，分別為8處（8/1 440，0.5%）和6處（6/1 440，0.4%）。頸部動脈血管斑塊最易出現鈣化，總計249處（249/1 440，17.3%），其次是軟斑塊和混合斑塊，均為39處（39/1 440，2.7%）。 結論　多層螺旋CT可準確評價頸動脈斑塊特征。

MRI常規掃描及彌散加權成像在宮頸癌評價中的價值

MRI常規掃描憑借著較高的軟組織分辨率對宮頸癌腫塊在宮頸內部的生長情況、腫塊對宮體的侵犯程度以及對宮旁癌周的侵犯、宮旁閉孔區淋巴結轉移的評價方面具有較高準確性和特異性。MRI常規掃描可提高宮頸癌的定位、定性、分期的準確性，有助于臨床國際婦產科聯盟（FIGO）分期。MRI彌散加權成像，作為功能磁共振的一種，是唯一一種可以評價活體組織內水分子彌散狀況的掃描方法，利用彌散加權成像獲得表觀彌散系數值可以對宮頸癌病灶組織病理學類型及分化程度、宮旁侵犯、淋巴結轉移進行定量定性分析。將彌散加權成像與常規掃描結合起來在診斷宮頸癌、協助臨床FIGO分期、制訂優化個體化治療方案及預后預測上有較大臨床應用價值。

The progress in imaging evaluation of liver iron concentration

ObjectiveTo summarize the methods and research progress of imaging evaluation of liver iron concentration.MethodsThe current status and progress of different imaging techniques in liver iron overload research were reviewed by studying the relevant literatures at home and abroad. The methods for determining liver iron concentration and their advantages and disadvantages were summarized.ResultsThe imaging methods for determining liver iron concentration mainly included traditional non-enhanced CT and dual energy CT examination, magnetic resonance signal intensity ratio, relative signal intensity index, T2 and R2 values, magnetic resonance spectroscopy, T2* and R2* values, susceptibility weighted imaging, and quantitative susceptibility mapping.ConclusionLiver iron quantification imaging method, including dual-energy CT and magnetic resonance imaging could non-invasively and accurately assess the liver iron overload.

多層螺旋CT輻射劑量控制與監督的臨床意義

【摘要】 多層螺旋CT檢查已經成為臨床診斷疾病的重要檢查手段，然而CT檢查產生的輻射劑量也越來越得到研究人員的關注。通過對MSCT輻射劑量的影響因素，降低MSCT輻射劑量的方法，合理選用CT檢查，規范化設置CT檢查方案，普及輻射防護知識，形成有效管理監督機制的論述、分析，探討MSCT輻射劑量控制與監督的臨床價值。

Application of Single-dose Contrast-enhanced Magnetic Resonance in Carotid Arteriography

目的　探討常規注射速率下單倍劑量對比劑在頸部三維對比增強磁共振血管成像（3D-CEMRA）中的可行性及臨床應用價值。 方法　2011年8月－11月，連續納入30例臨床懷疑頸動脈或椎動脈狹窄并要求頸部磁共振血管成像檢查的患者，隨機分成A、B兩組（每組各15例）。使用西門子Magnetom Avanto 1.5 T磁共振成像儀及其配備的頸部線圈和頭部線圈進行CEMRA成像。A組使用雙倍劑量對比劑（0.2 mmol/kg），B組使用單倍劑量對比劑（0.1 mmol/kg）。用三維快速小角度激發序列進行頸部血管成像。由2位有豐富經驗的高年資醫生對兩組原始圖像的信噪比以及最大密度投影（MIP）圖像的質量進行評價，并對結果進行統計學分析和處理。 結果　A、B兩組的所頸動脈信噪比分別為189.95 ± 71.31、175.07 ± 68.61，差異無統計學意義（t=?0.566，P=0.576）；所得的MIP圖像質量均達到優良，差異無統計意義（χ2=0.180，P=0.671）。 結論　與雙倍劑量相比，單倍劑量對比劑獲得頸部血管的圖像清晰，能夠滿足臨床診斷要求。