Cardiac computed tomography in the contemporary evaluation of infective endocarditis

Increasing data have accumulated on the role of Cardiac Computed Tomography (CCT) in infective endocarditis (IE) with high accuracy for large vegetations, perivalvular complications and for exclusion of coronary artery disease to avoid invasive angiography. CCT can further help to clarify the etiology of infective prosthetic valve dysfunction (e.g. malposition, abscess, leak, vegetation or mass). Structural interventions have increased the relevance of CCT in valvular heart disease and have amplified its use. CCT may be ideally integrated into a multimodality approach that incorporates a central role of transesophageal echocardiography (TEE) with 18-FDG PET and/or cardiac magnetic resonance in individually selected cases, guided by the Heart Team. The coronavirus-19 (COVID-19) pandemic has resulted in renewed attention to CCT as a safe alternative or adjunct to TEE in selected patients. This review article provides a comprehensive, contemporary review on CCT in IE to include scan optimization, characteristics of common IE findings on CCT, published data on the diagnostic accuracy of CCT, multimodality imaging comparison, limitations and future technical advancements.     

Diagnostic performance of cardiac computed tomography versus transesophageal echocardiography in infective endocarditis: A contemporary comparative meta-analysis

ObjectiveTo compare the diagnostic accuracy of transesophageal echocardiography (TEE) and cardiac computed tomography (CCT) in diagnosing infective endocarditis (IE).BackgroundTEE is a mainstay imaging modality for IE, while the use of CCT is becoming increasingly prevalent. Data directly comparing the diagnostic performance of these two imaging modalities for IE are limited.MethodsWe conducted a systematic review and meta-analysis of published literature in Embase, PubMed and Cochrane databases through October 1, 2020 for studies comparing diagnostic performance of CCT and TEE for the diagnosis of IE in the same patient populations. A meta-analysis of diagnostic accuracy was performed using the bivariate model based on studies that used surgical pathology as a reference standard for defining endocarditis. From a total of 10 studies included in the meta-analysis, a total of 872 patients were evaluated.ResultsThe pooled sensitivities and specificities of TEE for detecting vegetations were 96% and 83% respectively, whereas for CCT, they were 85% and 84%, respectively. In the prosthetic valve sub-group, the pooled sensitivities and specificities of TEE for detecting vegetations were 89% and 74% respectively, whereas for CCT, they were 78% and 94%, with CCT being more specific than TEE (p < 0.05). The pooled sensitivities and specificities of TEE for detecting periannular complications were 70% and 96% respectively, whereas for CCT, they were 88% and 93%, respectively. CCT showed a trend (p = 0.06) towards higher sensitivity than TEE for detection of periannular complications. The pooled sensitivities and specificities of TEE for detecting leaflet perforation were 79% and 93% respectively, whereas for CCT, they were 48% and 93% respectively, with TEE being more sensitive (p < 0.05). The two modalities also showed comparable diagnostic performance for detecting fistulae, paravalvular leaks and prosthetic valve dehiscence.ConclusionIn a contemporary comparative meta-analysis, TEE and CCT demonstrated both good diagnostic accuracy for detecting valvular involvement and complications of IE. TEE performed better for detecting leaflet defects, whereas CCT performed better in cases of prosthetic valve involvement, and showed a trend towards improved detection of periannular complications. Appropriate, complementary use of both TEE and CCT in a multimodality imaging approach in clinical practice may achieve the highest diagnostic performance.     

Brain magnetic resonance findings in infective endocarditis with neurological complications

Purpose  Diagnosing infective endocarditis and its complications can be difficult because of the nonspecific symptoms. We reviewed findings of intracranial abnormalities on magnetic resonance imaging (MRI) in 14 patients with neurological complications and herein discuss the overall intracranial MRI findings. Materials and methods  We retrospectively reviewed patients with infective endocarditis from August 2004 to August 2006. Brain MRI, the causative bacteria, and abnormal neurological symptoms were reviewed for 14 patients with neurological complications. Results  Of the 14 patients, 13 showed intracranial abnormalities on MRI. Embolization was seen in 10 patients, hemorrhage in 3, abscess formation in 3, and encephalitis in 2. Hyperintense lesions with a central hypointense area on T2-weighted and/or T2*-weighted imaging (Bull’s-eye-like lesion) were seen in four patients. A combination of these intracranial abnormalities was observed in 6 patients. Conclusion  The MRI findings associated with infective endocarditis are wide-ranging: embolization, hemorrhage, meningitis, cerebritis, abscess, the bull’s-eye-like lesion. Clinicians should consider the possibility of infective endocarditis in patients with unknown fever and neurological abnormality. Brain MRI should be promptly performed for those patients, and T2*-weighted imaging is recommended for an early diagnosis of infective endocarditis.     

Cardiac computed tomography improves the identification of cardiomechanical complications among patients with suspected left ventricular assist device malfunction

BackgroundLeft ventricular assist devices (LVAD) are increasingly used for durable mechanical circulatory support in advanced heart failure. While LVAD therapy provides substantial improvement in mortality and quality of life, long-term therapy confers increased risk for device complications. We evaluated if cardiac computed tomography (CCT) improves the detection of cardiomechanical complications among patients with LVAD and suspected device malfunction.MethodsIn this study, we compared the diagnostic performance of CCT and transthoracic echocardiography (TTE) for the identification of cardiomechanical LVAD complications, including thrombus or neointimal hyperplasia, inflow cannula malposition with dynamic obstruction, fixed outflow obstruction, device infection, and severe aortic regurgitation. Complications were confirmed with surgical evaluation, pathologic assessment, or response to therapeutic intervention.ResultsAmong 58 LVAD patients, who underwent CCT and TTE for suspected LVAD dysfunction, there were 49 confirmed cardiomechanical LVAD complications among 43 (74.1%) patients. The most common LVAD complication was thrombus or neointimal hyperplasia (65.3%), followed by dynamic obstruction (26.5%). Individually, CCT identified 29 of the 49 (59.2%) confirmed LVAD cardiomechanical complications, whereas TTE alone identified a complication in 11 cases (22.4%). However, diagnostic performance was greatest when the two modalities were used in combination, yielding a sensitivity of 67%, specificity of 93%, PPV of 97%, NPV of 47% and diagnostic accuracy of 73%.ConclusionThe novel and complementary use of CCT with TTE for the evaluation of suspected device malfunction improves the accurate identification of cardiomechanical LVAD complication compared to either modality alone.     

心电门控CT:一种对疑为主动脉人工瓣膜心内膜炎病人的新的检查方法

目的该前瞻性研究的目的是调查主动脉人工瓣膜心内膜炎病人在心电门控CT(ECG-CT)和经食管超声心动图(TEE)检查结果的一致性。材料与方法 27例主动脉人工瓣膜心内膜炎(PVE)病人进行了64层ECG-CT和TEE检查,并比较检查结果。影像学检查与手术结果相比较(16例病人进行了手术)。结果 TEE显示所有病人都存在PVE的表现,包括主动脉壁增厚(n=17)、赘生物(n=13)、脓肿(n=16)、瓣裂(n=10)。25例(93%)病人在ECG-CT检查中有阳性发现,包括主动脉壁增厚(n=19)、赘生物(n=7)、脓肿(n=18)、瓣裂(n=7)。ECG-CT和TEE检查的一致性(κ,95%CI),对于主动脉壁增厚非常好(0.83,0.62～1.0),对于脓肿(0.68,0.40～0.97)和瓣裂(0.75,0.48～1.0)较好,对于赘生物则是中度相关(0.55,0.26～0.88)。手术结果(脓肿、赘生物和瓣裂)与ECG-CT(0.66,0.49～0.87)和TEE(0.79,0.62～0.96)的影像学发现有较好的一致性,而联合应用ECG-CT和TEE则一致性更高(0.88,0.74～1.0)。结论研究结果表明ECG-CT的诊断效能与TEE相当,对于主动脉人工瓣膜心内膜炎病人ECG-CT可能是一种有价值的术前评估方法。     

ECG-gated computed tomography: a new role for patients with suspected aortic prosthetic valve endocarditis

Objectives

The aim of this prospective study was to investigate the agreement in findings between ECG-gated CT and transoesophageal echocardiography (TEE) in patients with aortic prosthetic valve endocarditis (PVE).

Methods

Twenty-seven consecutive patients with PVE underwent 64-slice ECG-gated CT and TEE and the results were compared. Imaging was compared with surgical findings (surgery was performed in 16 patients).

Results

TEE suggested the presence of PVE in all patients [thickened aortic wall (n?=?17), vegetation (n?=?13), abscess (n?=?16), valvular dehiscence (n?=?10)]. ECG-gated CT was positive in 25 patients (93?%) [thickened aortic wall (n?=?19), vegetation (n?=?7), abscess (n?=?18), valvular dehiscence (n?=?7)]. The strength of agreement [kappa (95?% CI)] between ECG-gated CT and TEE was very good for thickened wall [0.83 (0.62–1.0)], good for abscess [0.68 (0.40–0.97)] and dehiscence [0.75 (0.48–1.0)], and moderate for vegetation [0.55 (0.26–0.88)]. The agreement was good between surgical findings (abscess, vegetation and dehiscence) and imaging for ECG-gated CT [0.66 (0.49–0.87)] and TEE [0.79 (0.62–0.96)] and very good for the combination of ECG-gated CT and TEE [0.88 (0.74–1.0)].

Conclusion

Our results indicate that ECG-gated CT has comparable diagnostic performance to TEE and may be a valuable complement in the preoperative evaluation of patients with aortic PVE.     

Low-dose computed tomography to detect body-packing in an animal model

Objective

To assess the possible extent of dose reduction for low-dose computed tomography (CT) in the detection of body-packing (ingested drug packets) as an alternative to plain radiographs in an animal model.

Materials and methods

Twelve packets containing cocaine (purity >80%) were introduced into the intestine of an experimental animal (crossbred pig), which was then repeatedly examined by abdominal CT with stepwise dose reduction (tube voltage, 80 kV; tube current, 10-350 mA). Three blinded readers independently evaluated the CT datasets starting with the lowest tube current and noted the numbers of packets detected at the different tube currents used. In addition, 1 experienced reader determined the number of packets detectable on plain abdominal radiographs and ultrasound.

Results

The threshold for correct identification of all 12 drug packets was 100 mA for reader 1 and 125 mA for readers 2 and 3. Above these thresholds all 3 readers consistently identified all 12 packets. The effective dose of a low-dose CT scan with 125 mA (including scout view) was 1.0 mSv, which was below that of 2 conventional abdominal radiographs (1.2 mSv). The reader interpreting the conventional radiographs identified a total of 9 drug packets and detected 8 packets by abdominal ultrasound.

Conclusions

Extensive dose reduction makes low-dose CT a valuable alternative imaging modality for the examination of suspected body-packers and might replace conventional abdominal radiographs as the first-line imaging modality.     

Dermoid cysts and their complications as manifested by computed cranial tomography

Rupture of a dermoid cyst intracranially is well demonstrated by cranial computed tomography. This complication was previously thought to have very grave consequences. Two cases are presented with rupture of cyst contents into the ventricle and subarachnoid space. One patient had a history of “aseptic meningitis”. Both patients had hydrocephalus. Both patients did well after surgery.     

Improvement of sensitivity and interrater reliability to detect acute stroke by dynamic perfusion computed tomography and computed tomography angiography

OBJECTIVE: To assess the benefits of additional computed tomography perfusion (CTP) and computed tomography angiography (CTA) on the detection of early stroke, vessel occlusion, estimated infarct size, and interrater reliability. METHODS: Sixty-seven consecutive patients underwent nonenhanced computed tomography (CT) imaging, CTA, and CTP. The final diagnosis of stroke was made from follow-up neuroimaging. A first diagnosis was made on-site by the physician on duty. Three experienced neuroradiologists blinded to follow-up findings analyzed the data set off-line, evaluated CT for signs of acute stroke, and subsequently evaluated CTP and CTA for infarction-related perfusion deficits and vessel abnormalities. RESULTS: Computed tomography perfusion and CTA increased the time from CT start to diagnosis from 2 minutes to 10 minutes. Sensitivity to detect acute stroke increased significantly in all investigators from 0.46-0.58 to 0.79-0.90 compared with CT (<0.005). The interrater weighted kappa value increased from 0.35 to 0.64. Estimation of infarct size was not improved. CONCLUSION: Computed tomography perfusion and CTA provide an effective add-on to standard CT in acute stroke imaging by significantly increasing the sensitivity and reliability of infarct detection.     

High-resolution computed tomography of chest complications in patients treated with hematopoietic stem cell transplantation

Hematopoietic stem cell transplantation (HSCT) has become a standard method for treating patients with hematological malignancies. Preconditioning chemotherapeutic drugs, total body irradiation (TBI), or chronic graft-versus-host disease (GVHD) can cause several chest complications after HSCT. Because immunosuppression is marked after HSCT, it takes at least 1 year for the immune system to recover completely. Therefore, several infectious and noninfectious complications may occur within the year after HSCT. HSCT-specific complications occur in a characteristic temporal sequence associated with the period following HSCT. During the neutropenic phase, bacterial pneumonia, fungal infection, pulmonary edema, and diffuse alveolar hemorrhage may occur. During the early phase, pneumocystis pneumonia, cytomegalovirus pneumonia, engraftment syndrome, and idiopathic pneumonia syndrome are the common complications. During the late phase, constrictive bronchiolitis and organizing pneumonia may occur probably associated with chronic GVHD. Although high-resolution CT findings lack specificity, the frequency and likelihood of occurrence of certain complications in certain phases and sometimes characteristic features (such as a CT halo sign for fungal infection) facilitate early detection of a life-threatening complication.     

Evaluation of cerebral hemodynamics with computed tomography perfusion using gadolinium as an alternative to iodinated contrast: a case report

Computed tomography (CT) perfusion is traditionally performed using iodinated contrast, but this can be problematic in patients with impaired renal function or contrast allergy. We report a case of a 63-year-old man whose medical history was complicated by chronic renal failure, which was exacerbated after placement of a left cervical internal carotid artery stent by 70% stenosis and left hemisphere perfusion deficit. On a follow-up clinic visit, because of the patient s chronic renal failure, CT perfusion was performed successfully using gadolinium without further renal complications.     

MRI、正电子发射计算机体层成像和超声心动图鉴别存活心肌的对比研究

、准确性的P值均<0.01).LDDSE的敏感性、特异性和准确性分别为70.1%(47/67)、70.4%(50/71)和70.3%(97/138),敏感性与DE-MRI相当(P0.05),特异性和准确性则低于DE-MRI(P均<0.05).结论 DE-MRI是一种很有应用价值和发展潜力的评价存活心肌的方法.     

Standardized whole-body computed tomography as a screening tool in blunt multitrauma patients

The authors present the potential of using a preset CT protocol covering the whole body of the patient who has suffered blunt trauma to screen for injuries, based on a review of the literature and on 4 years' direct experience. Standardized whole-body CT is the fastest method of examining the whole body, capable of detecting a wide variety of traumatic lesions with a high sensitivity and specificity. Multidetector CT allows a full-body examination to be completed within 5 min, thus minimizing time to diagnosis and the institution of definitive clinical care. Current imaging algorithms that include abdominal ultrasonography and plain radiographic studies need to be reassessed in view of the technical advances in CT diagnosis, but should ultimately depend on the particular imaging capabilities and experience of a given trauma center.     

Improved detection of viable myocardium with fluorodeoxyglucose-labeled single-photon emission computed tomography in a patient with hibernating myocardium: Comparison with rest-redistribution thallium 201-labeled single-photon emission computed tomography

Conclusion  The findings presented in this patient support the concept of “hibernation” as first described by Rahimtoola⁵. Coronary revascularization resulted in recovery of both regional perfusion and regional and global ventricular function in this patient that was accompanied by improvement in functional status. At present, many techniques are available for the identification of myocardial viability.⁴ In this case we demonstrated that FDG SPECT was able to identify viability and predict functional recovery after revascularization that was underestimated by rest-redistribution ²⁰¹Tl imaging. Miller⁶ has recently described discordant results between low-dose dobutamine echocardiography and rest-redistribution ²⁰¹Tl imaging in a patient considered for revascularization in whom ²⁰¹Tl imaging was superior. That report and our case emphasize the need for comparative studies in patients undergoing revascularization to establish the relative merits of the various techniques that are currently available to assess viable myocardium.     

Usefulness of 40-slice multidetector row computed tomography to detect coronary disease in patients prior to cardiac valve surgery

Preoperative identification of significant coronary artery disease (CAD) in patients prior to valve surgery requires systematic invasive coronary angiography. The purpose of this current prospective study was to evaluate whether exclusion of CAD by multi-detector CT (MDCT) might potentially avoid systematic cardiac catheterization in these patients. Eighty-two patients (53 males, 62 ± 13 years) scheduled to undergo valve surgery underwent 40-slice MDCT before invasive quantitative coronary angiography (QCA). According to QCA, 15 patients had CAD (5 one-vessel, 6 two-vessel and 4 three-vessel disease). The remaining 67 patients had no CAD. On a per-vessel basis, MDCT correctly identified 27/29 (sensitivity 93%) vessels with and excluded 277/299 vessels (specificity 93%) without CAD. On a per-patient basis, MDCT correctly identified 14/15 patients with (sensitivity 93%) and 60/67 patients without CAD (specificity 90%). Positive and negative predictive values of MDCT were 67% and 98%. Performing invasive angiography only in patients with abnormal MDCT might have avoided QCA in 60/82 (73%). MDCT could be potentially useful in the preoperative evaluation of patients with valve disease. By selecting only those patients with coronary lesions to undergo invasive coronary angiography, it could avoid cardiac catheterization in a large number of patients without CAD. This work was supported by a grant of the Fondation Nationale de la Recherche Scientifique of the Belgian Government (FRSM 3.4557.02). Dr. Pouleur is supported by a personal grant of the Fondation Nationale de la Recherche Scientifique of the Belgian Government.