Non-invasive computed tomography coronary angiography as a gatekeeper for invasive coronary angiography

To determine the rate of subsequent invasive coronary angiography (ICA) and revascularization in relation to computed tomography coronary angiography (CTA) results. In addition, independent determinants of subsequent ICA and revascularization were evaluated. CTA studies were performed using a 64-row (n = 413) or 320-row (n = 224) multidetector scanner. The presence and severity of CAD were determined on CTA. Following CTA, patients were followed up for 1 year for the occurrence of ICA and revascularization. A total of 637 patients (296 male, 56 ± 12 years) were enrolled and 578 CTA investigations were available for analysis. In patients with significant CAD on CTA, subsequent ICA rate was 76  %. Among patients with non-significant CAD on CTA, subsequent ICA rate was 20 % and among patients with normal CTA results, subsequent ICA rate was 5.7 % (p < 0.001). Of patients with significant CAD on CTA, revascularization rate was 47 %, as compared to a revascularization rate of 0.6 % in patients with non-significant CAD on CTA and no revascularizations in patients with a normal CTA results (p < 0.001). Significant CAD on CTA and significant three-vessel or left main disease on CTA were identified as the strongest independent predictors of ICA and revascularization. CTA results are strong and independent determinants of subsequent ICA and revascularization. Consequently, CTA has the potential to serve as a gatekeeper for ICA to identify patients who are most likely to benefit from revascularization and exclude patients who can safely avoid ICA.     

Endosonography versus helical computed tomography for locoregional staging of gastric cancer

BACKGROUND AND STUDY AIMS: Endosonography (EUS) has been shown to be more accurate than incremental computed tomography (CT) in the local (T) and regional (N) staging of gastric carcinoma; however, EUS has never been compared with helical CT (HCT). The fifth edition of the TNM classification changed the guidelines for N-staging of gastric carcinoma. The accuracy of imaging methods in this new system remains unknown. PATIENTS AND METHODS: Staging accuracy of EUS and HCT were compared prospectively with pathological or intraoperative findings in 88 gastric carcinoma patients. Staging was done according to the fourth and fifth editions of the TNM classification. EUS was done with a radial echo endoscope, and HCT with a scanner with two rows of detectors (two-phase contrast-enhanced scanning of a water-filled stomach). RESULTS: The T-staging accuracy of EUS (63 %, CI 52 - 73 %) was superior to the accuracy of HCT (44 %, CI 34 - 55 %; P = 0.021). N-staging accuracy of both methods was similar when the fourth edition of the TNM classification was used (EUS 47 %, CI 34 - 60 %; HCT 52 %, CI 38 - 65 %). However, HCT was more accurate than EUS when the fifth edition of the classification was applied (EUS 30 %, CI 18 - 43 %, HCT 47 %, CI 34 - 60 %; P = 0.044). The accuracy of detection of lymph node metastases was similar for both methods (EUS 67 %, CI 54 - 78 %; HCT 77 %, CI 64 - 86 %). CONCLUSIONS: EUS is more accurate than HCT in the T-staging of gastric carcinoma. Both methods are comparable for N-staging, when this is done according to the older, fourth edition of the TNM classification. If the fifth edition is used, EUS is less accurate than HCT.     

Preoperative evaluation of periampullary tumors by endoscopic sonography, transabdominal sonography, and computed tomography.

PURPOSE: The purpose of this retrospective study was to compare the sensitivity of endoscopic sonography (EUS), transabdominal sonography (US), and CT in the detection of, local staging of, and prediction of vascular involvement by or distant metastasis from periampullary tumors. METHODS: Seventy-four consecutive patients with presumed periampullary tumors were evaluated by EUS, US, and CT during a 3.25-year period. The local staging accuracy of the modalities was assessed in the 36 patients with solid tumors who underwent surgery. The sensitivity of the modalities in predicting vascular involvement and distant metastasis was assessed in the 56 patients with carcinomas. RESULTS: EUS was the most sensitive modality in the detection (EUS, 97%; US, 24%; and CT, 39%; p < 0.001 for EUS versus US or CT) and T classification (EUS, 72%; US, 11%; CT, 22%; p < 0.001 for EUS versus US or CT) of periampullary tumors. EUS also had better sensitivity than US in detecting lymph node metastasis from periampullary cancers (EUS, 47%; US, 7%; and CT, 33%; p = 0.02 for EUS versus US; p = 0.7 for EUS versus CT). The accuracy of EUS in determining the T classification (without stent, 81%; with stent, 65%) and N classification (without stent, 80%; with stent, 70%) tended to decrease in the presence of an endobiliary stent, but the differences were not significant. EUS was the most sensitive modality in demonstrating vascular involvement (EUS, 100%; US, 0%; and CT, 33%; p = 0.002 for EUS versus US; p = 0.03 for EUS versus CT) but was not significantly different in detecting distant metastasis (EUS, 11%; US, 44%; and CT, 44%). CONCLUSIONS: EUS is superior to US and CT in the local assessment of periampullary tumors. The staging accuracy of EUS is minimally but not significantly affected by the presence of an endobiliary stent.     

CT血管造影与MR血管造影对颅内动脉瘤诊断价值的对比研究

目的通过CTA检查结果与MRA检查结果的对比分析,探讨二者在诊断颅内动脉瘤中的临床应用价值。材料与方法回顾性分析60例高度怀疑颅内动脉瘤患者的DSA影像资料,及其CTA或MRA图像,在60例行DSA检查患者中,行CTA检查者30例,行MRA检查者30例。图像后处理采用最大密度投影(MIP)和容积重建(VR),以DSA检查结果及行动脉夹闭术作为诊断动脉瘤的标准,比较CTA和MRA对颅内动脉瘤的显示情况。结果在60例中,DSA和动脉瘤夹闭术共证实30个动脉瘤,其中30例16个动脉瘤CTA显示良好,30例14个动脉瘤MRA显示良好。CTA发现颅内动脉瘤的敏感性为93.3%特异性为86.7%准确性为90.0%,MRA发现颅内动脉瘤的敏感性为60.0%特异性为66.7%准确性为63.3%。结论头颈部CTA检查能够快速、安全、无创、有效的诊断脑动脉瘤,可作为临床筛查大部分颅内动脉瘤的首选检查方法。     

The relationship of computed tomography and ultrasonography in diagnosis of abdominal disease.

A detailed comparison of computed tomography and ultrasonography of the abdomen is presented from a theoretical point of view. The advantages and limitations of both modalities are discussed in terms of scan content, resolution, plane of interrogation, dynamic imaging, examination time, imaging problems, automation, contrast administration, puncture guidance, examination availability, hazards, personnel and space requirements, and cost. Analysis of these factors leads the authors to conclude that ultrasound should be the procedure of choice for sectional imaging of the abdomen. Computed tomography should be reserved for those situations in which the ultrasound examination is not diagnostic (i.e., skeletal system, lungs, mediastinum).     

Use of spiral computed tomography contrast angiography and ultrasonography to exclude the diagnosis of pulmonary embolism in the emergency department

Spiral computed tomography (CT) contrast angiography is a promising imaging modality for the diagnosis of pulmonary embolism but the negative predictive value of this test remains controversial. We performed a multi-center prospective cohort study to determine the safety of relying on a negative spiral CT contrast angiography scan to exclude pulmonary embolism. Patients presenting to the Emergency Departments of three tertiary care institutions with clinically suspected pulmonary embolism were potentially eligible for the study. Patients underwent a clinical evaluation to categorize pretest probability into low, moderate, and high categories, and had D-dimer testing performed. Patients at low pretest probability with normal D-dimer were considered to have pulmonary embolism excluded. The remaining patients underwent spiral CT contrast angiography scan of the pulmonary arterial circulation and bilateral venous ultrasound of the proximal leg veins. Patients who were confirmed to have pulmonary embolism or deep vein thrombosis were treated with anticoagulant therapy. Patients in whom the diagnosis of pulmonary embolism was excluded did not receive anticoagulant therapy and were followed for a 3-month period for the development of venous thromboembolic complications. Eight hundred fifty-eight (858) patients were enrolled in this study. Three-hundred sixty-nine (369) patients had low pretest probability and negative D-dimer results and no further diagnostic tests were performed. None of these patients subsequently developed venous thromboembolic complications (0%, 95% confidence interval [CI] 0% to 1.0%). The remaining 489 were referred for spiral CT contrast angiography scan and ultrasound. Sixty-seven patients were confirmed to have pulmonary embolism and an additional 15 patients with negative CT scans had proximal deep vein thrombosis (DVT) on ultrasound for a total prevalence of venous thromboembolism of 82/489 (16.8%). Two of 409 patients who had pulmonary embolism excluded in the initial evaluation phase developed proximal venous thromboembolism (0.5%; 95% CI 0% to 1.8%) in the 3-month follow-up period. These findings suggest that the combination of a negative spiral CT contrast angiography scan and normal venous ultrasound imaging safely excludes the diagnosis of pulmonary embolism in the Emergency Department setting.     

彩色多普勒超声与64层CT血管造影在巨细胞颞动脉炎诊断中的应用价值

目的探讨彩色多普勒超声与CT血管造影（CTA）检查在巨细胞动脉炎临床诊断中的应用价值。方法2006年10月至2008年11月在山东省医学影像学研究所风湿免疫科住院患者21例,经彩色多普勒超声诊断巨细胞颞动脉炎后,所有病例均进行颞浅动脉CT强化扫描检查并行颞浅动脉血管三维重建CTA。21例病例均进行颞动脉活检。结果彩色多普勒超声在所有21例病例中共检出病变血管32条,巨细胞动脉炎的超声形态学特征性改变为：二维超声图像上表现为血管壁回声减低,血管壁呈向心性增厚,血管腔内径变窄,病变血管呈节段性改变;在彩色多普勒血流显像检查时颞动脉血管腔周围有一特征性的低回声晕,血管腔狭窄,血管腔内血流信号呈周边充盈缺损样改变,当血管腔闭塞时血管腔内无血流信号显示;或者血管内膜呈不规则增厚,回声增强,血管腔不规则狭窄,类似于动脉硬化斑块形成。所有21例患者1次颞浅动脉血管CTA检查均可清晰成像,共检出病变血管30条,病变血管狭窄时,血管腔内影像显示对比剂浓度变淡,血管边缘处对比剂呈不规则充盈缺损改变,部分病变段血管腔内径呈特征性串珠样改变;血管闭塞时,正常血管走行区域对比剂显示中断、消失。21例颞动脉活检病例中阳性者占19例,64层螺旋强化CT血管成像检查诊断正确符合率为90．4％（19／21）,彩色多普勒超声诊断与病理活检结果相符者19例,占所有病例的90．4％（19／21）。结论高分辨率彩色多普勒超声和64层螺旋强化CT血管成像在诊断巨细胞颞动脉炎中能够清楚地显示颞动脉及分支血管狭窄或闭塞,为临床诊断巨细胞颞动脉炎提供准确的诊断依据,并可用以替代传统的创伤性数字造影检查。在诊断功能上可替代病变血管组织病理活检,减少患者的痛苦,具有重要的临床价值和社会效益。     

Optimization of energy level for coronary angiography with dual-energy and dual-source computed tomography

Dual-energy computed tomography (DE-CT) uses polyenergetic X-rays at 100- and 140-kVp tube energy, and generates 120-kVp composite images that are referred to as polyenergetic images (PEIs). Moreover, DE-CT can produce monoenergetic images (MEIs) at any effective energy level. We evaluated whether the image quality of coronary angiography is improved by optimizing the energy levels of DE-CT. We retrospectively evaluated data sets obtained from 24 consecutive patients using cardiac DE-CT at 100- and 140-kVp tube energy with a dual-source scanner. Signal-to-noise ratios (SNRs) were evaluated in the left ascending coronary artery in PEIs, and in MEIs reconstructed at 40, 50, 60, 70, 80, 90, 100, 130, 160 and 190 keV. Energy levels of 100, 120 and 140 kVp generated the highest SNRs in PEIs from 10, 12 and 2 patients, respectively, at 60, 70 and 80 keV in MEIs from 2, 10 and 10 patients, respectively, and at 90 and 100 keV in those from one patient each. Optimization of the energy level for each patient increased the SNR by 16.6% in PEIs (P < 0.0001) and by 18.2% in MEIs (P < 0.05), compared with 120-kVp composite images. The image quality of coronary angiography using DE-CT can be improved by optimizing the energy level for individual patients.     

Renal ultrasonography as a tool for detecting dynamic changes in blood pressure.

Renal ultrasonography has been used to assess renal blood flow under pathological conditions. We attempted to determine if sonographically derived renal resistive index measurements would be affected by subtle changes in flow as a consequence of transiently induced mild increases in blood pressure in persons with normal renal functioning. Nine subjects free of structural renal disease were studied with duplex Doppler ultrasonography. Main renal artery resistive indices were determined under resting baseline conditions and in response to graded infusions of phenylephrine sufficient to increase blood pressure by approximately 13/5 mm Hg. Change in blood pressure correlated with the change in main renal artery resistive index (r = 0.254, P < 0.05). Thus, the resistive index varies in association with transient increases in blood pressure and may reflect concurrent alterations in distal resistance under physiologic conditions.     

Immediate computed tomography coronary angiography versus delayed outpatient stress testing for detecting coronary artery disease in emergency department patients with chest pain

Noninvasive testing for coronary artery disease (CAD) is warranted for symptomatic patients with intermediate pretest likelihood of CAD. Accomplishing testing in an emergency department (ED) environment is challenging. We compared two strategies of CAD testing in ED patients: immediate computed tomography coronary angiography (CTCA) versus delayed outpatient stress testing. We conducted a historical control cohort study comparing symptomatic ED patients without an acute coronary syndrome who warranted noninvasive CAD testing. Two cohorts (50 patients each) were defined by CAD testing strategy, immediate CTCA versus delayed stress testing. Outcomes were duration of ED stay, detection of CAD, and 3-month rates of readmission, myocardial infarction, (MI) or death. Median duration of stay was 417.5 minutes (interquartile range [IQR] 359.0–581.0) in the CT cohort and 400.0 minutes (IQR 338.0–471.0) in the control cohort (P = 0.53). CAD was detected in 14 CT cohort patients versus 1 in control (P = 0.0004), due to low follow-up in the control cohort (18 of 50, 36%). Obstructive CAD was diagnosed in 6 CT cohort patients versus 1 in control (P = 0.11). During 3 months of follow-up, four patients in each cohort were reevaluated in the ED for chest pain; no patients suffered MI or death. A strategy of immediate CTCA is superior to a delayed stress testing strategy for detecting CAD in ED patients with chest pain and prompting appropriate referrals for further management. Delayed stress testing was primarily ineffective due to low follow-up. Immediate CTCA can be used safely without altering the ED duration of stay.     

Staging of hepatocellular carcinoma by ultrasonography,computed tomography,and angiography: The role of CT combined with arterial portography

A series of 60 patients with hepatocellular carcinoma (HCC) were evaluated over a 2-year period of ultrasonography (US), computed tomography (CT), and angiography. The angiographic studies carried out with intraarterial digital technology were compared to both US and CT of the liver. In 16 of 60 patients, we observed discordance of the findings obtained with angiography, CT, and US. We therefore compared these three methodologies in those cases where diagnostic discordance was noted. In our experience, US had a sensitivity of 73.4%, 76.7% for CT, and 95% for angiography. In 13 of 60 patients, we performed CT with arterial portography (CTAP) which demonstrated a better resolution than conventional CT. In view of the sensitivity of US — comparable to that of CT — and for the even greater sensitivity of intraarterial digital angiography, we performed an US study of patients at risk of HCC. CT was found to play a diagnostic/staging role after angio graphic study has been performed, especially when enhanced by arterial portography.     

Comparative sensitivity of computed tomography vs. magnetic resonance imaging for detecting acute posterior fossa infarct

Background

Posterior fossa strokes, particularly those related to basilar occlusion, pose a high risk for progression and poor neurological outcomes. The clinical history and examination are often not adequately sensitive or specific for detection.

Study Objectives

Because this population stands to benefit from acute interventions such as intravenous and intra-arterial tissue plasminogen activator, mechanical thrombectomy, and intensive monitoring for neurologic deterioration, this study examined the sensitivity of non-contrast head computed tomography (NCCT) for diagnosing posterior fossa strokes in the emergency department.

Methods

This study analyzed a prospectively collected database of acute ischemic stroke patients who underwent head NCCT within 30 h of symptom onset and who were subsequently found to have a posterior fossa infarct on brain magnetic resonance imaging (MRI) performed within 6 h of the NCCT.

Results

There were 67 patients identified who had restricted diffusion on MRI in the posterior fossa. The National Institutes of Health Stroke Scale (NIHSS) scores ranged from 0 to 36, median 3. Only 28 patients had evidence of infarction on the initial NCCT scan. The timing of NCCT scans ranged from 1.2 to 28.9 h after symptom onset. The sensitivity of NCCT was 41.8% (95% confidence interval 30.1–54.4). The longest period of time between symptom onset and a negative NCCT with a subsequent positive diffusion-weighted imaging MRI was 26.7 h.

Conclusions

Head NCCT imaging is frequently insensitive for detecting posterior fossa infarction. Temporal evolution of strokes in this distribution, coupled with beam-hardening artifact, may contribute to this limitation. When a posterior fossa stroke is suspected and the NCCT is non-diagnostic, MRI is the preferred imaging modality to exclude posterior fossa infarction.     

Recurrent hepatocellular carcinoma: usefulness of ultrasonography compared with computed tomography and AFP assay.

Follow-up studies using monitoring with alpha1-feto protein (AFP), ultrasonography (US), and computed tomography (CT) were carried out in 75 patients who had prior partial hepatectomy for hepatocellular carcinoma (HCC). Recurrence in the remaining liver was confirmed in 31 patients (41.3%) during the 4 month to 3 years 7 month period. Ultrasonography detected recurrence in 29 cases (sensitivity: 93.5%), CT in 26 (83.9%), and AFP assay in 12 (38.7%). In 4 patients, ultrasonography detected four recurrent nodules that CT missed. In 1 patient, two subphrenic nodules were detected with CT but not with ultrasonography. The specificity of US, CT, and AFP assay was 90.9%, 95.5%, and 93.2% respectively. Frequent follow-up study with ultrasonography in combination with CT and AFP assay should be recommended for the early detection of recurrent HCC. Ultrasonography is mandatory for the follow-up of patients with a prior hepatectomy for HCC.