CT窗技术在急性胰腺炎诊断中的作用

目的探讨CT窗技术在急性胰腺炎诊断中的作用。资料与方法搜集经临床、实验室检查及手术证实的50例急性胰腺炎患者的影像资料,由两名高年资影像诊断医师采取盲法进行软读片,同时采用常规腹部窗宽、窗位和适当调节窗宽、窗位技术观察胰腺周围改变,以胰周脂肪间隙混浊、胰周胰外积液、胰包膜掀起、肾前筋膜增厚等为阳性指征,将调节组中阳性率高于常规组的诊断结果分别与常规组进行配对χ2检验。结果经比较,窗宽100～200HU、窗位-60～-40HU组阳性率最高,且与常规组诊断结果比较阳性率差异有统计学意义(χ2=8.1,P<0.05)。结论在常规腹部窗宽、窗位的基础上适当缩窄窗宽、降低窗位进行观察,有利于发现急性胰腺炎胰腺周围的阳性征象,提高CT在临床诊断急性胰腺炎中的辅助作用。     

CT诊断肺栓塞中的显示窗设置

目的 评价CT窗技术对肺栓塞(pulmonary embolism,PE)的诊断价值.资料与方法 搜集26例临床确诊为PE的多层螺旋CT肺动脉造影资料,应用下列7种显示窗,统计26例患者检出的PE阳性血管数:(1)常规窗(窗宽350 HU,窗位40 HU);(2)调节窗(窗宽1000 HU,窗位400 HU);(3)调节窗+常规窗及文献中4种专为诊断PE而设的显示窗.不同显示窗诊断结果差异性比较采用成对样本t检验,以P＜0.05为统计学意义.结果 使用常规窗+调节窗诊断PE检出阳性支数最多(347支),与其他6种窗设置比较差异均有统计学意义(P＜0.01),单独使用常规纵隔窗或调节窗将会发生7%～9%的漏诊率.结论 在PE的CT诊断中,联合应用窗宽较宽、窗位较高的窗设置技术可提高对PE的诊断水平.     

气体造影及窗技术在CT诊断胃肠病变中的应用

目的 探讨空气造影低剂量CT扫描及低窗位图像诊断肠道病变的应用价值.方法 126例疑有胃或结肠病患者随机分为2组,一组(69例)采用传统的水造影或无造影常规剂量CT扫描及常规窗位诊断,另一组(57例)采用空气造影低剂量CT扫描及低窗位图像诊断,以内窥镜检查为诊断标准,由资深医生采用单盲法评价诊断,比较2组图像的诊断自信度及正确率.结果 医生对空气造影低剂量cT扫描及低窗位图像的诊断自信度和正确率明显优于传统的水造影或无造影常规剂量cT扫描常规窗位图像.结论 充气造影低剂量CT及窗位技术诊断胃结肠病变明显优越于传统检查方法,值得提倡.     

CT窗宽技术对原发性大网膜梗死的诊断价值

目的探讨CT窗宽技术对腹部原发性大网膜梗死的诊断价值。方法选取并分析22例临床确诊为腹部原发性大网膜梗死患者的腹部CT资料,固定窗位为50 HU,分别使用窗宽135 HU、250 HU(腹部)、350 HU(纵隔)、500 HU分析比较病变检出率。结果窗宽为135 HU、250 HU(腹部)、350 HU(纵隔)、500 HU对腹部网膜病变的检出率分别为13.64%(3例)、63.64%(14例)、100%(22例)、100%(22例),但是500 HU对腹部肠管及实质脏器显示较350 HU差。结论综合图像质量认为350 HU(纵隔)窗宽是诊断原发性大网膜梗死的理想窗宽。     

螺旋CT测量日本大耳白兔气道径线的窗宽窗位选择

目的探讨日本大耳白兔气管和主支气管解剖径线CT测量的窗位与窗宽选择,为气道支架动物实验奠定基础。方法多层螺旋CT扫描30只成年健康日本大耳白兔的胸部,分别常规肺窗、纵隔窗和特殊的脂肪窗测量气管胸段前后径、左右径、左右主支气管前后径。比较不同窗宽窗位下气管壁显示以及测量数据与解剖数据之间的差异。结果肺窗气管壁均清晰显示,但测量的结果偏小;纵隔窗气管壁显示模糊,测量的结果偏大;而脂肪窗气管壁显示均匀,测量的数据比较接近实际气管直径的解剖参数。结论多层螺旋CT测定日本大耳白兔气管左右径和前后径应选择脂肪窗为佳。有助于为人相关气管和支气管定制气道支架确定最佳的窗宽和窗位。     

床旁CR显示窗应用

目的:回顾性随机抽取术后床旁胸部正位有阳性并发症的CR影像1000人次,评价调整窗宽、窗位对显示影像病变结构的作用,探讨CR窗宽、窗位的调整在数字化影像显示时的最佳参数,做好术后床旁胸片显示的质量保证。方法:应用GE Centricity Sp100成像系统Musica后处理软件,由3名来自不同诊断组别(胸组、腹组、乳腺组)的主治医师在工作站显示屏上对影像显示情况进行分析,记录下他们认为可以显示不同病变的最佳窗宽、窗位值;然后对获得的所有数据进行统计学分析,找出术后胸部各种病变诊断的最佳显示值。结果:观察数字重叠影像的不同组织结构,存在普遍接受的窗宽、窗位参考值域。本组3位主治医师对不同病变最佳窗宽窗位观察值的定义有差别。经SPSS 13.0软件包的频数分析,笔者推导出适用于不同年龄、男女、体型、疾病且大部分医师都认可的一系列床旁CR显示窗值,其中窗宽值为液气胸(1.040～1.219)、气腹(0.930～1.182)、气胸(0.668～1.025)、骨折(0.954～1.168)、皮下气肿(0.969～1.411)、胸腔积液(0.988～1.516)和肺炎(1.152～1.322),窗位值为液气胸(1.278～1.553)、气腹(1.131～1.520)、气胸(1.574～1.894)、骨折(1.377～1.661)、皮下气肿(1.263～1.645)、胸腔积液(1.212～1.546)和肺炎(1.300～1.678)。结论:不同层次的病变结构需要在特定的窗宽、窗位下观察才利于影像诊断。参与这个评价过程的人越多,可获得一系列具有普适性的参考值域。而被普遍接受的数字图像,有利于摄影技师设置激光打印胶片图像参数。临床医师软阅读重叠数字影像以及医学图像共享的实现。     

儿童头颅CT窗宽、窗位探讨

成人头颅无论大小还是密度 ,个体间差异较小。而儿童则不同 ,从刚出生到 14岁 ,个体差异较大。为了获得优质的CT影像 ,在CT扫描时 ,必须选择适当的扫描条件和窗宽、窗位[1] 。笔者着重讨论不同年龄段儿童头颅CT的窗宽、窗位选择情况。1　资料与方法使用GESynergyCT扫描仪 ,3M激光相机 ,AGFA自动洗片机 ,其中显影液温度设置为 2 8℃ ,密度计 ,观片灯。将儿童划分为 5个年龄段 ,具体为新生儿 (2 8天以内 ) ,2个月～ 1岁 ,2～ 4岁 ,5～ 8岁 ,9～ 14岁。采用相同的扫描条件 (12 0kV ,130mA ,2s)对患者进行扫描。在每个年龄段分别选出 2 …     

CT虚拟结肠镜检查中窗技术对病变测量影响的研究

目的通过实验研究CT虚拟结肠镜（CTVC）肺窗和软组织窗技术在测量结肠病变中的应用价值。方法洗净的新鲜猪大肠一段（约150cm），人工模拟息肉样病变24枚，用胶水随意将其固定于肠壁内各处。将猪大肠充满空气后置于盛满水的容器中，采用64层CT以相同的扫描参数对其连续扫描10次，将所得数据经0．625mm重组后传至GEAW4．2工作站。运用CTVC专用软件重组出结肠的轮廓和肠腔内模拟病变的情况，由2名具有10年以上工作经验的放射科医师运用专用的CTVC测量工具对每个模拟病变的最大直径进行测量。分别在肺窗（窗宽1000HU，窗位-700HU）和腹部软组织窗（窗宽400HU，窗位40HU）下各测1次，共测量10次，并求出每个模拟病变测量10次后所得直径的平均值，将所得结果与模拟病变真实直径进行对比。结果24枚模拟病变的形态、大小、位置以及病变与肠壁之间的关系均得到良好的显示。每次测量的模拟病变的最大直径与病变真实直径均较接近，平均值大多数略小于真实直径，少数略大于真实直径。运用肺窗技术所测得的病变最大直径的平均值为（5．97＋2．50）mm，模拟病变的真实直径的平均值为（6．28＋2．47）mm，2组数据间差异无统计学意义（t=0．431，p=0．669）；而在腹部软组织窗位下所测量的结果为4．38intn，与病变真实直径间差异具有统计学意义（t=2．691，p=0．010）。结论CTVC对于结肠病变的筛查具有无刨或微创的优点，可重复性强。在CTVC检查中宜采用肺窗技术对病变大小进行测量。     

CT在骨肿瘤及肿瘤样病变诊断中的应用

应用CT对骨肿瘤及肿瘤样病变的研究,迄今已有十几年历史,其价值亦日益受到重视。本文综述近年来的有关骨肿瘤与肿瘤样病变的CT表现。检查方法取前后位或侧位获得定位像,或做体表标志定位。根据需要适当调整扫描架角度,或用软垫纠正体位,使扫描面与兴趣区平行。肢体检查需置两侧同时进行扫描,并尽量使双侧体位均称,扫描始或终层面应包括一端关节。层厚8～10cm。兴趣区可采用薄层或重叠扫描,欲行重建,则宜行薄层扫描。观察骨结构窗宽800HU,窗位100～140HU;软组织病变或骨病变的软组织部份,窗宽400HU,窗位0～20HU。有些病变如骨髓瘤,窗宽与窗位应适当调整,一般采用     

读片窗

诊断经过　经详细询问病史 ,患者诉每次咯血与经期一致 ,且于 3年前有 2次刮宫史 ,1年前曾行绝育术 ,2次就诊以及X线和CT检查均处于行经期。嘱患者停止抗结核治疗并于月经干净 1周后复查 ,CT扫描示病变范围明显缩小 ;经期后 1 5天再次复查 ,CT示病变完全消失 (图 3) ;下次月经期在原部位病变再次出现 (图 4 )。根据患者病史及动态观察 ,诊断为肺内子宫内膜异位症。临床给予中药治疗 ,患者症状减轻。图 3　月经干净后 15天CT平扫示肺野清晰 ,病灶完全消失图 4　再次行经时复查 ,CT平扫示病灶再次出现讨论　本例为生育期妇女 ,多次在月经…     

Liver and bone window settings for soft-copy interpretation of chest and abdominal CT

OBJECTIVE: We evaluated whether the use of multiple window and level settings on a soft-copy workstation improves diagnostic accuracy on chest and abdominal CT. We hypothesized that routinely using window and level settings during soft-copy interpretation would beneficially affect the final diagnosis without compromising efficiency. MATERIALS AND METHODS: Two hundred three randomly selected abdominal and chest CT scans were interpreted by three radiologists using a four-monitor soft-copy workstation (images per screen, nine; resolution, 2K). After the initial interpretations, all scans were reevaluated by the same radiologists using additional liver and bone window and level settings. Differences in conspicuity and characterization of abnormalities were graded on a three-point scale. RESULTS: Conspicuity and characterization of abnormalities were improved in 67% of abnormal findings (81/121; p = 0.01). Improvement (a finding that substantially affected the final diagnosis) was present in 18% of abnormal findings (22/121; p = 0.04). On average, the evaluation of images at multiple window and level settings required an additional 40 sec per case. CONCLUSION: The use of multiple window and level settings during soft-copy interpretation resulted in improved lesion detectability and characterization with greater diagnostic efficacy. Using soft-copy workstations, radiologists can evaluate images using multiple settings without compromising efficiency.     

CT detection of hepatic and splenic injuries: usefulness of liver window settings

OBJECTIVE. This study was designed to assess the usefulness of liver window settings when performing abdominal CT for the detection and characterization of hepatic and splenic injuries. SUBJECTS AND METHODS. We prospectively evaluated helical abdominal CT scans for hepatic and splenic injuries in 300 consecutive patients with blunt abdominal trauma over a 4-month period. There were 204 males and 96 females with a mean age of 34 years (age range, 1-87 years). For each patient, initial CT diagnosis of hepatic or splenic injury was made from images obtained with standard abdominal window settings. CT scans were then immediately reinterpreted using additional images obtained at narrow window width (liver windows). Changes in conspicuity and characterization of injury were recorded. All CT examinations were performed with helical 7-mm collimation at a pitch of 1.5 after oral ingestion of diluted barium and during bolus IV administration of 125 mL of ioversol at a rate of 2-3 mL/sec. RESULTS. We detected hepatic or splenic injuries in 34 patients (11.3%). There were 19 hepatic injuries and 18 splenic injuries. Three patients had injuries to both liver and spleen. Conspicuity of hepatic or splenic injuries was mildly increased (+1 H) on liver windows in 16 patients, whereas the injury was equally conspicuous on both liver window and standard window images in 19 cases. In no case did review of the liver windows result in a change in grade of injury or reveal an injury that was not seen on standard abdominal window images. The total increased cost for printing liver windows was $5748. CONCLUSION. Routine use of liver window settings for abdominal CT in trauma patients has little clinical usefulness and is not cost-effective.     

Colonic polyps: effect of attenuation of tagged fluid and viewing window on conspicuity and measurement--in vitro experiment with porcine colonic specimen

PURPOSE: To investigate effect of attenuation of tagged fluid and viewing window on polyp conspicuity and measurement with porcine colonic specimen. MATERIALS AND METHODS: Eleven (3-10-mm-diameter) polyps were created in porcine colon and the specimen submerged in saline. Four-detector row CT was performed after gas distension and after filling with six barium sulfate suspensions (attenuation, 100-1000 HU). Two readers independently measured maximal two-dimensional polyp diameter on each data set with the following four viewing windows and window levels and window widths, respectively: colon (-150 HU, 1500 HU), lung (-500 HU, 1500 HU), bone (500 HU, 2500 HU), and abdomen (40 HU, 400 HU). In consensus, polyp conspicuity (compared with air data set) was assigned a grade of 1-4 for each viewing window (grade 1, not seen or barely visible; grade 4, optimally seen). For statistical analysis, conspicuity grades were collapsed to a two-point scale. Data were analyzed with Mann-Whitney, Kruskal-Wallis, and chi2 tests. RESULTS: Accuracy of polyp measurement was independent of viewing window for attenuation of tagged fluid of 100-300 HU but differed significantly for 500-1000 HU (P < .001); that for colonic and bone viewing windows was superior (median size difference, 1.0 mm; interquartile range, 0.5-1.5). Conspicuity differed significantly according to viewing window at all attenuation values (P < .001). For 100-300 HU with abdominal viewing window, 83% (24 of 29) of observations were assigned grade 3 or 4 (best). For 500-1000 HU with bone viewing window, 94% (30 of 32) of observations were assigned grade 3 or 4 (superior). Overall conspicuity was best with bone viewing windows at 700 HU. CONCLUSION: Polyp conspicuity and measurement in tagged data sets were optimized at 700 HU with bone viewing windows. At less than 300 HU, conspicuity improved with abdominal viewing windows.     

Helicobacter pylori gastritis mimicking gastric carcinoma at CT evaluation

The abdominal computed tomographic (CT) scans from 61 patients with biopsy-proved Helicobacter (formerly Campylobacter) pylori gastritis were retrospectively reviewed. The CT scans were interpreted on the basis of the original report of the findings at CT examination and without knowledge of the results of biopsy. Of 19 patients (31%) with gastric abnormalities at CT, 14 (74%) had inflammatory changes initially reported as suspicious for gastric malignancy; malignancy was entertained as the primary diagnosis in four of those patients. In five of the 19 abnormal cases (26%), the diagnosis with CT was gastritis. The two major patterns of severe H pylori infection identified were (a) circumferential antral wall thickening and (b) thickening of the posterior gastric wall along the greater curvature, with or without evidence of ulceration. Thickening averaged 1.5-2.0 cm in cases suspicious for malignancy. The majority of abnormalities involved the gastric antrum (68%). No cases demonstrated significant adenopathy, obliteration of fat planes, or invasion of adjacent organs.     

Combined multi-kernel chest computed tomography images optimized for depicting both lung and soft tissue

PurposeTo evaluate the quality of our improved multi-kernel chest computed tomography (CT) images.MethodsA random sample of 50 normal patients was retrospectively selected from those who underwent chest CT scans between January 2010 and July 2010. Normal lung structures were divided into six categories, and two radiologists independently compared with lung images.ResultsThe improved multi-kernel images were displayed identically to soft tissue images on soft tissue window settings and were evaluated as equal to lung images on lung window settings.ConclusionsThis improved multi-kernel technique required fewer stored images and simplified examinations of chest CT.     

Pneumatosis intestinalis in association with sigmoid volvulus: Value of lung windows during abdominal computed tomography

An 80-year-old man presented with progressive left-sided abdominal pain and distention. His abdominal plain radiograph revealed a focally dilated, redundant loop of sigmoid colon, having a mottled appearance. A computed tomographic (CT) scan with soft tissue settings showed no evidence of pneumatosis; however, with lung window settings [mean, —600 Hounsfield units (HU); width, 1000 HU], intramural pockets of air were seen in the bowel wall. The pneumatosis was presumed secondary to recurrent sigmoid volvulus. The utility of CT lung windows to evaluate the gastrointestinal tract in patients with acute abdominal conditions cannot be overemphasized.     

Stomal metastases complicating percutaneous endoscopic gastrostomy: CT findings and the argument for radiologic tube placement

OBJECTIVE: This article describes the CT appearance of metastatic implantation at the percutaneous endoscopic gastrostomy (PEG) tract in patients with malignancy of the upper aerodigestive tract. Cumulative data from previous case reports are also considered for insight into causes of metastasis and the implications for gastrostomy placement in these patients. CONCLUSION: CT showed lobulated soft tissue involving the entire abdominal wall PEG tract in all proven cases. CT is an effective method for evaluation because the tumor burden lies predominately in the abdominal wall and not at the entry or exit site. The stomal implant is often the only site of metastatic disease at presentation. In general, CT findings of mildly increased soft tissue along the PEG tract are nonspecific, but a lobulated mass is highly suspicious for tumor implantation, especially if the one-sided thickness exceeds 1 cm. The preponderance of evidence from the existing literature points to direct tumor implantation during endoscopic placement as the likely cause (rather than hematogenous spread). This conclusion would support the alternative of radiologic tube placement in these patients.     

Impact of different window settings on colon polyp measurements with CT virtual colonoscopy: a phantom study

The aim of this study was to evaluate the impact of window settings on measurement of colon polyps with CT virtual colonoscopy with experiment. Twenty-four artificial polyps' diameter were measured and scanned 10 times with identical scan parameters using a 64-multidetector computed tomographic scanner. The diameter of each polyp was measured using lung window and abdominal soft tissue window settings and compared with the actual diameter. The lung window setting offers accurate measurement of colon polyps.     

CT窗口技术在诊断恶性骨肿瘤的应用

目的 研究不同窗宽窗位在恶性骨肿瘤诊断中的价值。材料与方法 分别在骨窗、软组织窗及中间窗下,对28例经手术病理证实的恶性骨肿瘤患者的CT表现进行回顾性统计学分析,比较不同窗口条件下CT对恶性骨肿瘤的诊断率。结果 骨窗能明确反映骨肿瘤骨密度异常的区域,而软组织窗及中间窗对显示肿瘤周围软组织和骨皮质受侵犯以及水肿等更敏感。结果 窗口技术对骨肿瘤的定性和分期具有重要的诊断价值。     

Low-dose multislice CT of the thorax in follow-up of malignant lymphoma and extrapulmonary primary tumors

Our objective was to study the impact of low-dose multislice thoracic CT on image quality and lesion conspicuity in follow-up of patients with malignant lymphoma and extrapulmonary primary tumors. Forty consecutive patients with a history of malignant lymphoma or extrapulmonary malignant primaries who had undergone previous standard-dose thoracic spiral CT (120 kVp, 150 mAs, 8 mm) were subjected to low-dose multislice CT (15 mAs/rotation, 120 kVp, pitch 1.5, 4×2-mm collimation reconstructed to contiguous 8-mm slices. Image quality and lesion conspicuity were classified independently by two readers on a four-point ordinal scale (1=poor, 4=excellent). Mean image quality was significantly lower for low-dose CT, 2.35, than for standard-dose CT, 3.25 (p<0.001); however, all low-dose CT examinations were fully readable, none had to be repeated, and no lesions (including 51 lung lesions and 31 soft tissue lesions) remained undetected. Only in the apical lung did the lowered tube current significantly reduce lesion conspicuity. Even in pulmonary lesions smaller than 10 mm (n=21) lesion conspicuity did not significantly differ between standard and low-dose scans. Low-dose thoracic multislice CT based on a 90% reduction in dose compared with standard-dose techniques was not associated with impaired detection of suspicious lesions and may be useful in follow-up of malignant lymphoma and extrapulmonary tumors. Electronic Publication