64层螺旋CT冠状动脉成像对冠心病的诊断价值

目的：评价64层螺旋CT对冠心病的诊断价值。方法：对25例典型病例的CT图片进行分析、总结,观察64层螺旋CT对冠状动脉的管腔狭窄程度及冠脉内斑块性质的显示能力,并对桥血管和支架通畅性进行观察。结果：近端冠脉中度以上狭窄的敏感度、准确度、阳性预测值分别为93.5%,90.3%,88.5%,对左主干及前降支病变诊断价值较高;对冠状动脉内软斑块显示较佳;对桥血管及支架通畅和有无再狭窄显示良好。结论：MSCT冠状动脉成像在冠心病筛查及冠状动脉支架术后和搭桥术后的随访发挥重要作用。     

多层螺旋CT对下颌骨骨折的诊断价值

目的探讨多层螺旋CT对下颌骨骨折的诊断价值。方法对2007年4月2009年10月下颌骨不同部位骨折的45例患者进行多层螺旋CT轴位扫描,并行多平面、表面遮盖法等三维重建,对下颌骨骨折CT表现特征作回顾性分析。结果 45例下颌骨骨折中,位于下颌体骨折24例,下颌角骨折5例,下颌升支骨折6例,髁部骨折13例,冠突骨折2例;颞下颌关节脱位中,单侧脱位3例,双侧脱位5例。结论多层螺旋CT能准确诊断下颌骨各部位骨折,对诊治方案具有重要价值。     

Model-based Iterative Reconstruction: A Promising Algorithm for Today's Computed Tomography Imaging

Because of its fast image acquisition and the rich diagnostic information it provides, computed tomography (CT) has gradually become a popular imaging modality among clinicians. Because CT scanners emit x-rays, the increased use of CT in clinical applications inevitably leads to increased medical radiation dose to the population. Because of the well-known cancer-inducing effects of high dose x-ray radiation, this increased dose has caused concerns among policy makers and general public that CT patients may be at a higher risk of developing cancer. Over the years, CT manufacturers have developed a variety of strategies to address this issue, the latest being a model-based iterative reconstruction (MBIR) algorithm. MBIR is an advanced CT algorithm that incorporates modeling of several key parameters that were omitted in earlier algorithms to reduce computational requirement and speed up scans. This review article examines the latest literature in the clinical CT field and discusses the general principles of MBIR, its dose and noise reduction potentials, its imaging characteristics, and its limitations. MBIR algorithm and its application in today's CT imaging will greatly reduce the radiation dose to patients and improve image quality for clinicians.     

The effect of hormone replacement therapy and/or exercise on skeletal muscle attenuation in postmenopausal women: a yearlong intervention

Hormone replacement therapy (HRT) has been reported to exert a positive effect on preserving muscle strength following the menopause, however, the mechanism of action remains unclear. We examined whether the mechanism involved preservation of muscle composition as determined by skeletal muscle attenuation. Eighty women aged 50-57 years were randomly assigned to either: HRT, exercise (Ex), HRT+exercise (ExHRT), and control (Co) for 1 year. The study was double-blinded with subjects receiving oestradiol and norethisterone acetate (Kliogest) or placebo. Exercise included progressive high-impact training for the lower limbs. Skeletal muscle attenuation in Hounsfield units (HU) was determined by computed tomography of the mid-thigh. Areas examined were the quadriceps compartment (includes intermuscular adipose tissue), quadriceps muscles, the posterior compartment and posterior muscles. Muscle performance was determined by knee extensor strength, vertical jump height, and running speed over 20 m. Fifty-one women completed the intervention. Vertical jump height and running speed improved in the HRT and ExHRT groups compared with Co (interaction, P<0.01). For both the quadriceps compartment and quadriceps muscles, HU significantly increased (interaction, P相似文献   

Cumulative Doses of Ionizing Radiation From Computed Tomography: A Population-Based Study

ObjectiveTo assess cumulative radiation doses from computed tomography (CT), patient characteristics, and clinical indications for CT in a population-based sample.Patients and MethodsA cohort study using medical records linkage through the Rochester Epidemiology Project was conducted to ascertain all CT examinations in Olmsted County, Minnesota, performed between January 1, 2004, and December 31, 2013, among all adults who were alive for 3 or more years after the end of follow-up (to exclude exposures preceding death). Ten-year cumulative effective ionizing radiation doses were estimated on the basis of typical doses per CT modality. Among patients with high doses (≥100 mSv/10 years), CT scans were reviewed for clinical setting, indications, and results.ResultsOf 54,447 adults (median age, 44.0 years at inclusion), 26,377 (48.4%) underwent at least one CT. Ten-year radiation doses from CT were 0.1 to 9.9 mSv in 15.8% of the population (8593 patients), 10 to 24.9 mSv in 16.9% (9502), 25 to 99.9 mSv in 13.8% (7492), and 100 mSv or greater in 1.9% (1041). Computed tomography of the abdomen and pelvis accounted for 67.2% of the estimated dose. In multivariable models, doses differed 1.21-fold to 2.16-fold between extreme categories of age, body mass index, education level, smoking status, and by race. Of 600 CTs in 200 patients with high doses, 70.5% were obtained for restaging of solid cancers and lymphoma, abdominal pain, infection, kidney stones, follow-up of nodules or masses, and chest pain/evaluation for pulmonary embolism.ConclusionExposure to ionizing radiation from CT occurred disproportionally in specific subgroups of the population. A limited number of clinical indications contributed the majority of radiation among adults with high doses.     

The Role of Cranial Computed Tomography in the Diagnostic Work-up of Headache

Approximately 18% of all patients referred for a cranial computed tomography complain of headache only.
We reviewed 363 consecutive patients in order to assess the value of this examination in the diagnostic approach.
Despite the vast number of normal examinations (88.4%), we advocate the routine use of a cranial computed tomography in every patient with chronic headache. The cost of the examination can significantly be reduced by performing an unenhanced scan only. An additional contrast-enhanced scan should be obtained if a suspicious lesion is seen. Brain magnetic resonance imaging is not indicated except in the preoperative workup of a lesion visualized on computed tomography.     

Computed Tomography Measurements of Hepatic Steatosis in Cholelitihiasis and Cholecystectomy Cases Using Unenhanced Images

IntroductionComputed tomography (CT) measurements of hepatic steatosis can be performed using unenhanced CT images. The purpose of this study was to assess the occurrence of hepatic steatosis using unenhanced CT images for patients undergoing cholecystectomy or having cholelithiasis.MethodsA total of 143 unenhanced CT cases from a single centre were retrospectively examined. The CT number of liver, ratio of CT number of liver to spleen, and CT number of liver minus CT number of spleen were measured in three groups: (1) patients undergoing cholecystectomy, (2) patients having cholelithiasis, and (3) control group. Abdominal circumference, anterior subcutaneous fat tissue thickness, and body mass index were obtained.ResultsMean CT number of liver was significantly different between the group of patients with cholecystectomy and cholelithiasis and the control group (P < .001) and also between cases of cholecystectomy and cholelithiasis (P = .041), with the lowest CT number of liver in the cholecystectomy group. The mean CT number of liver minus CT number of spleen and mean CT number (liver/spleen) ratios, evaluated separately for both lobes, were not different comparing the cholelithiasis and cholecystectomy groups. The mean CT number of liver minus CT number of spleen and mean CT number (liver/spleen) ratios differed significantly between the control group and both patient groups (P < .001). Positive correlations were identified between abdominal circumference, subcutaneous fat depth, body mass index, and liver size and hepatic steatosis.ConclusionThere was an increased occurrence of hepatic steatosis in patients who have undergone a cholecystectomy compared with patients treated for cholelithiasis and the control group.     

Computed Tomographic Localization of Malposition of Pacing Electrodes: The Value of Cardiovascular Computed Tomography

Three patients with uncertain pacemaker electrode position on plain film radiography were studied with fast cine cardiovascular computed tomography (CT) imaging. The value of this new technique in determining the position of pacing electrodes is discussed.     

A Decision Guideline for Emergency Department Utilization of Noncontrast Head Computed Tomography in HIV-infected Patients

OBJECTIVE: To determine which neurologic signs or symptoms are predictive of new focal lesions on head CT in HIV-infected patients. METHODS: Prospective study with convenience sample enrollment of HIV-infected patients who presented to a large inner-city university-based ED over an 11-month period. Patients were assessed using a standardized neurologic evaluation to ascertain whether they had developed new or changed neurologic signs or symptoms. Patients with any new or changed neurologic findings had a head CT scan in the ED. The association between individual complaints or findings and new focal lesions on head CT was assessed by univariate analysis, and sensitivity, specificity, and positive predictive values were calculated. Stepwise logistic regression analysis was then carried out to estimate the relative risk for those variables independently associated with new focal lesions on CT scans. A decision guideline was developed incorporating those variables. RESULTS: One hundred ten patients were identified as having new or changed neurologic signs or symptoms and had a head CT done in the ED. Twenty-seven patients (24%) had focal lesions on head CT, of which 19 (18%) were identified as new focal lesions; eight of these (7%) demonstrated a mass effect. Clinical findings most strongly associated with new focal findings on head CT were: 1) new seizure, relative risk (RR) = 73.5, 95% CI = 6.2 to 873.0; 2) depressed or altered orientation, RR = 39.1, 95% CI = 4.6 to 330.0; and 3) headache, different in quality, RR = 27.0, 95% CI = 3.2 to 230.1. Use of these three findings as a screen for ordering head CT in the ED would have identified 95% (18/19) of the patients with new focal intracranial lesions, and resulted in a 53% reduction in the number of head CTs ordered in the ED. Inclusion of one additional parameter (prolonged headache, > or =3 days), would have resulted in identification of 100% of all new focal lesions, with a 37% reduction in the number of head CTs ordered. Among those patients with new focal findings, 74% required emergent management (i.e., seizure control, IV antibiotics, IV steroids or surgery). The most common intracranial lesion among patients with CD4 counts less than 200 cells/microL was toxoplasmosis, while cerebrovascular accidents (ischemic or hemorrhagic) were most common in those with CD4 counts greater than 200 cells/microL. CONCLUSION: Specific clinical signs and symptoms were associated with the presence of new intracranial lesions in a group of HIV-infected patients who presented to the ED with neurologic complaints. These clinical findings can be incorporated into guidelines for determining the need for emergent head CT. Validation and widespread application of these guidelines could result in limiting the use of emergent neuroimaging to a more well-defined HIV-infected patient population.     

Systematic Review: The Role of Intravenous and Oral Contrast in the Computed Tomography Evaluation of Acute Appendicitis

BackgroundThis systematic review provides practicing emergency physicians updated information regarding the role of oral and intravenous contrast in the computed tomography (CT) evaluation of acute appendicitis.MethodsA PubMed literature search was conducted from January 1, 1996 to December 31, 2018 and limited to human clinical trials written in English with relevant keywords. High-quality studies were identified and then underwent a structured review. Recommendations are made based on the literature review.ResultsFifty-seven articles met criteria for rigorous review, of which 14 were appropriate for citation in this review. Excellent evidence shows that oral contrast does not improve the test characteristics of CT with intravenous contrast (IVCT) in the evaluation of adults suspected of having acute appendicitis. Good evidence shows that noncontrast abdominal CTs have excellent test characteristics for this same group of patients.ConclusionsConsidering its downsides and lack of utility, the medical literature does not support using oral contrast in the evaluation of acute appendicitis. There is no direct evidence showing that IVCT is better than a noncontrast CT in the evaluation of acute appendicitis; however, the available literature is consistent with slightly better test characteristics for IVCTs. Still, if IVCT cannot be obtained in a timely manner, noncontrast CTs are extremely accurate in detecting this disease.     

Impact of Helical Computed Tomography on the Outcomes of Emergency Department Patients with Suspected Appendicitis

OBJECTIVES: To assess the impact of an emergency department (ED) guideline employing selective use of helical computed tomography (CT) on clinical outcomes of female patients with suspected appendicitis. METHODS: All patients presenting with suspected appendicitis were prospectively enrolled and managed in accordance with a guideline incorporating selective use of helical CT. Although not the objective of this investigation, male patients were included for purposes of comparison. Patients with clinically evident appendicitis were referred to the surgical service, and patients with equivocal presentations were studied with helical CT. Patients were followed to final surgical or clinical outcomes. Outcome measures included time from ED presentation to laparotomy and rate of appendiceal perforation. These measures were compared with those of a historical cohort of patients preceding the use of helical CT. RESULTS: A total of 310 consecutive patients with suspected appendicitis were enrolled; 92 had appendicitis. Sixty patients were referred to the surgical service without helical CT, and 41 had appendicitis (68%). Helical CT was performed on 250 patients; 51 had appendicitis (20%). For males, the mean interval from ED presentation to laparotomy was 559 minutes (95% CI = 444 to 674 minutes) during guideline use and 480 minutes (95% CI = 405 to 555 minutes) before. This interval for females was 433 minutes (95% CI = 326 to 540 minutes) during guideline use and 710 minutes (95% CI = 558 to 862 minutes) before. Appendiceal perforation rate for males was 0.25 (95% CI = 0.14 to 0.36) during guideline use and 0.38 (95% CI = 0.29 to 0.47) before; perforation rate for females was 0.06 (95% CI = -0.05 to 0.17) during guideline use and 0.23 (95% CI = 0.14 to 0.32) before. Helical CT had 92% sensitivity, 97% specificity, and 96% accuracy in diagnosing appendicitis. CONCLUSIONS: Helical CT is highly accurate in detecting appendicitis in patients with equivocal ED presentations. The use of a guideline employing selective helical CT was associated with a decline in the time from ED presentation to operative intervention in females.     

Pediatric Computed Tomography Dose Optimization Strategies: A Literature Review

IntroductionComputed tomography (CT) dose optimization is an important issue in radiography because CT is the largest contributor to medical radiation dose and its use is increasing. However, CT dose optimization for pediatric patients could be more challenging than their adult counterparts. The purpose of this literature review was to identify and discuss the current pediatric CT dose saving techniques. Optimized pediatric protocols were also proposed.MethodsA comprehensive literature search was conducted using the Medline, ProQuest Health and Medical Complete, PubMed, ScienceDirect, Scopus, Springer Link, and Web of Science databases and the keywords CT, pediatric, optimization, protocol, and radiation dose to identify articles focusing on pediatric CT dose optimization strategies published between 2004 and 2014.Results and SummarySeventy-seven articles were identified in the literature search. Strategies for optimizing a range of scan parameters and technical considerations including tube voltage and current, iterative reconstruction, diagnostic reference levels, bowtie filters, scout view, pitch, scan collimation and time, overscanning, and overbeaming for pediatric patients with different ages and body sizes and compositions were discussed. An example of optimized pediatric protocols specific to age and body size for the 64-slice CT scanners was devised. It is expected that this example could provide medical radiation technologists, radiologists, and medical physicists with ideas to optimize their pediatric protocols.     

Subarachnoid Hemorrhage Diagnosis: Lumbar Puncture Is Still Needed When the Computed Tomography Scan Is Normal

Objectives: To determine the sensitivity of third-generation CT scanners for diagnosed nontraumatic subarachnoid hemorrhage (SAH) and to assess the impact of symptom duration on sensitivity.
Methods: A retrospective chart review was performed in a university-affiliated tertiary care hospital with an annual ED volume of >100,000 patients. The target population was all patients who presented to the ED from January 1991 to September 1994 with symptoms suggestive of SAH and who had a final diagnosis of nontraumatic SAH based on either a positive CT scan or positive spinal fluid analysis. Patients referred from outside facilities were included if they had a CT done at the study site. All CT scans were done using third-generation scanners. Official CT scan reports were used to categorize scans as positive or negative.
Results: There were 140 patients identified with SAH, with a mean age of 56 years (range 10–88). The sensitivity of CT in the diagnosis of nontraumatic SAH when performed at or before 12 hours of symptom duration was 100% (80/80), and 81.7% (49/60) after 12 hours of symptom duration (95% CI 95–100% and 69.5–90.4%, respectively; p < 0.0001). Eleven of the 140 patients had a negative CT and positive spinal fluid analysis, yielding an overall sensitivity of 92.1% (129/140).
Conclusion: The sensitivity of third-generation CT scans for SAH decreases with time from the onset of symptoms. In this sample population, CT was able to detect all patients scanned ^12 hours after symptom onset. Although the study demonstrated good sensitivity of CT scan reports for SAH when the scan was performed after S12 hours of symptom onset, additional real-time experience is needed to better define the potential risk of a missed SAH should this population not receive the customary lumbar puncture examination in the setting of a negative CT scan.     

SPECT与CT对鼻咽癌颅底骨侵犯检测的比较

目的探讨SPECT及CT对鼻咽癌颅底骨侵犯的检测能力。方法 2006年5月-2009年12月对159例经病理确诊的初治鼻咽癌患者行颅底SPECT断层显像,同期行CT检查,分别计算颅底受侵的阳性率。结果①159例鼻咽癌SPECT颅底断层阳性率46.5%（74/159）,CT阳性率25.2%（40/159）,SPECT检测敏感性高于CT（P〈0.001）。②鼻咽癌伴颅神经损害SPECT检测敏感性高于CT（P=0.004）。结论 SPECT对鼻咽癌颅底骨侵犯的检测敏感性优于CT。     

Needle Thoracostomy: Implications of Computed Tomography Chest Wall Thickness

OBJECTIVES: To determine the length of catheter required to perform a needle thoracostomy, as determined by chest wall thickness, to treat the majority of patients presenting to the emergency department (ED) with a potential tension pneumothorax. METHODS: A convenience sample of 111 computed tomography (CT) scans of the chest in trauma and medical resuscitation patients at a military Level 1 trauma center in San Antonio, Texas, was pooled, and the chest wall thickness was measured at the second intercostal space, midclavicular line, to the nearest 0.1 cm. RESULTS: The mean chest wall thickness in the patients studied averaged 4.24 cm (95% confidence interval [CI] = 3.97 to 4.52). Nearly one fourth (25) of the study patients had a chest wall thicker than 5 cm. Women, on average, have thicker chest walls than men (4.90 for women; 4.16 for men; p = 0.022). CONCLUSIONS: In this study, a catheter length of 5 cm would reliably penetrate the pleural space of only 75% of patients. A longer catheter should be considered, especially in women.     

核素心肌显像和活动平板运动试验对冠心病的诊断价值

目的以冠状动脉造影(CAG)结果为标准,评价核素心肌显像(SPECT)、活动平板运动试验(TET)及两者合用对冠心病的诊断价值。方法97例患者同期(1周)内行CAG、SPECT及TET,将其结果进行对比分析。结果SPECT和TET对冠心病诊断的敏感性分别为87.1%、83.9%,特异性分别为34.8%、77.3%,对双支病变的检出率分别为83.3%、100%。除敏感性外,两者之间均存在统计学差异(P0.05),且两者合用对于左前降支(LAD)、左回旋支(LCX)及轻、中度病变的检出率与TET、SPECT比较,差异均有统计学意义(P0.05)。结论作为冠心病的筛选检查,TET具有价格便宜、简单实用、准确率较高等优点,是临床冠心病筛查的主要方法之一;与SPECT合用可明显提高检出率。     

The Role of Computed Tomography in the Diagnostic Work‐Up of Headache Patients in Nigeria

Objective.— To determine the yield of computed tomography (CT) scan of the brain in the evaluation of patients presenting with headache at the University of Port Harcourt Teaching Hospital (UPTH). Background.— Headache is a pain in the head or upper neck. It is one of the most common locations of pain in the body that leads patients to see a physician. CT scan is invaluable as an imaging tool in assessment of intracranial lesions that may present with headache. Methods.— The records of all the patients referred from a variety of inpatient and outpatient settings to the radiology department of UPTH with the main complaint of headache for brain (CT) scan were identified. Data extracted include referral source, indication for CT, age, sex, presenting complaint, duration of headache, and CT findings. The data were analyzed using SPSS 14.0 statistical package. Results.— A total of 80 patients with chronic or recurrent headache met the selection criteria. The age range was 16 to 85 years with a mean of 39.8 ± 14.62 years. There were 36 males and 44 females with male to female ratio of 1 : 1.2. About half of the patients were ≤45 years. Of the total number, 72 (90%) patients had normal CT findings, 2 (2.5%) had cerebral atrophy, 2 (2.5%) had cerebral edema, 2 (2.5%) had intracerebral hematoma while 1 (1.25%) patient each had cerebral infarction and subdural hematoma, respectively. There was no case of brain tumor. Conclusions.— The yield of correctable abnormalities from routine CT scan of the brain in headache patients with normal neurologic findings is low and does not justify its use in a resource poor country. (Headache 2010;50:1346‐1352)     

对系统评价/Meta分析报告规范的系统评价

目的全面收集系统评价/Meta分析的报告规范并对其进行评价,为系统评价/Meta分析的规范化发表及传播提供帮助。方法电子检索Ovid MEDLINE(1996～2010)及EMbase(截至2010年4月),纳入系统评价/Meta分析报告规范的文献,检索词包括guideline、report、systematic reviews、meta-analyses。通过阅读文题及摘要,排除无明显相关性的文献(针对具体疾病的系统评价,某一疾病的临床指南,以及仅讨论如何进行系统评价而未关注如何进行系统评价的报道等),而后进一步阅读全文,从纳入文献中提取如何报告系统评价/Meta分析的部分,并据其纳入原始研究设计的类型如随机对照试验、观察性研究、诊断性试验进行分类。结果初检获得285篇文献,最终纳入26篇文献。其中随机对照试验的系统评价/Meta分析报告规范有8篇,非随机对照试验(观察性研究)的系统评价/Meta分析报告规范2篇,诊断性试验的系统评价/Meta分析报告规范0篇,动物实验的系统评价/Meta分析报告规范1篇,针对系统评价/Meta分析的检索策略的报告规范2篇,评估系统评价/Meta分析质量的5篇,研究报告规范对系统评价/Meta分析质量影响的6篇。有2个指南更新。结论目前系统评价/Meta分析报告规范数量较多,其中QUOROM及其更新版本PRISMA被众多期刊广泛采纳。报告规范有利于提高系统评价和Meta分析的报告质量,尚需制定针对具体专业系统评价/Meta分析的报告规范。