Imaging of thoracic aortic disease

Clinical application of pulse-gated non-enhanced rapid magnetic resonance imaging in the definitive diagnosis of aortic dissection

OBJECTIVE

Aortic Dissection (AD) is one of the most fatal acute diseases in cardiovascular diseases, with rapid onset and progression and a high fatality rate. This study aims to investigate the clinical values of non-enhancement peripheral pulse-gating rapid magnetic resonance imaging in deterministic diagnosis of AD.

METHODS

Aorta magnetic resonance imaging was performed in 21 healthy volunteers at a 1.5t MR scanner sequences including cardiac-gated and peripheral pulse-gated True-FISP and HASTE were carried out separately. Acquisition Time (TA), Signal to Noise Ratio (SNR), Contrast Noise Ratio (CNR), and entirety of vessel wall blood flow artifacts were measured and compared. A total of 56 AD cases were displayed by non-enhancement peripheral pulse-gating fast MR imaging, and the results were compared with pathological findings or CTA of the aorta. The dissection rupture, tear film, true and false lumen, thrombosis, hydropericardium, and the main branches of AD were evaluated respectively.

RESULTS

There were no significant differences in SNR, CNR, entirety of the vessel wall, and blood flow artifact between cardiac-gated and peripheral pulse-gated fast MR imaging. Non-enhancement pulse-gated fast scanning takes less TA time. By the pulse-gated non-enhancement fast MR imaging, the dissection rupture, tear film, true and false cavity, thrombosis, hydropericardium, and the main branches of aortic dissection were shown clearly. Multi-planar and multi-angle scans helped to show the extent of entrapment rupture, whereas partial complex tears or bi-directional tears were slightly less well visualized.

CONCLUSION

Non-enhancement peripheral pulse-gated rapid magnetic resonance imaging can be used for deterministic diagnosis of AD.

Image quality, contrast enhancement and radiation dose of electrocardiograph- versus non-electrocardiograph-triggered computed tomography angiography of the aorta

INTRODUCTION

Computed tomography angiography of the aorta (CTAA) is the modality of choice for investigating aortic disease. Our aim was to evaluate the image quality, contrast enhancement and radiation dose of electrocardiograph (ECG)-triggered and non-ECG-triggered CTAA on a 256-slice single-source CT scanner. This allows the requesting clinician and the radiologist to balance radiation risk and image quality.

METHODS

We retrospectively assessed the data of 126 patients who had undergone CTAA on a single-source CT scanner using ECG-triggered (group 1, n = 77) or non-ECG-triggered (group 2, n = 49) protocols. Radiation doses were compared. Qualitative (4-point scale) and quantitative image quality assessments were performed.

RESULTS

The mean volume CT dose index, dose length product and effective dose in group 1 were 12.4 ± 1.9 mGy, 765.8 ± 112.4 mGy cm and 13.0 ± 1.9 mSv, respectively. These were significantly higher compared to group 2 values (9.1 ± 2.6 mGy, 624.1 ± 174.8 mGy cm and 10.6 ± 3.0 mSv, respectively) ( P < 0.001). Qualitative assessment showed the image quality at the aortic root-proximal ascending aorta was significantly higher in group 1 (median 3) than in group 2 (median 2, P < 0.001). Quantitative assessment showed significantly better mean arterial attenuation, signal-to-noise ratio and contrast-to-noise ratio in ECG-triggered CTAA compared to non-ECG-triggered CTAA.

CONCLUSION

ECG-triggered CTAA in a single-source scanner has superior image quality and vessel attenuation of aortic root/ascending aorta, but a higher radiation dose of approximately 23%. Its use should be considered specifically when assessing aortic root/ascending aorta pathology.

Aortic Aneurysm Mimicking Inferior ST-Elevation Myocardial Infarction: A Case Report

Here, we report a rare case of a 22-year-old female presenting with recurrent chest pain mimicking inferior ST-elevation myocardial infarction (STEMI) but ultimately attributed to an aortic aneurysm. Despite facing initial challenges in diagnosis, such as normal troponin levels and temporary electrocardiogram (ECG) changes, advanced imaging showed a large mass in the chest pressing on the right coronary artery. Prompt multidisciplinary intervention, including surgical resection of the aneurysm, led to successful management and improved outcomes. This case highlights the importance of considering unusual etiologies in atypical presentations of myocardial infarction, necessitating comprehensive evaluation and collaboration among various specialties for optimal patient care.

Thoracic Aortic Aneurysmal Disease: Comprehensive Recommendations for the Primary Care Physician

Thoracic aortic aneurysm (TAA) is a commonly encountered disease that is defined as aortic dilation with an increase in diameter of at least 50% greater than the expected age- and sex-adjusted size. Thoracic aortic aneurysms are described by their size, location, morphology, and cause. Primary care clinicians and other noncardiologists are often the first point of contact for patients with TAA. This review is intended to provide them with basic information on the differential diagnosis, diagnostic evaluation, and medical and surgical management of TAAs. Management decisions depend on having as precise a diagnosis as possible. Fortunately, this can often be achieved with a stepwise diagnostic approach that incorporates imaging and targeted genetic testing. Our review includes recommendations. In this review, we discuss these issues at a basic level and include recommendations for patients considering pregnancy.

Incidental finding of undiagnosed aortic coarctation in an elderly patient with a rare association with thymic carcinoma: a case report with review of the literature

Aortic coarctation is a congenital malformation that is relatively prevalent, occurring in approximately 5 out of every 1000 births. The narrowing typically happens at the aortic isthmus between the left subclavian artery and the arterial ligament. It is frequently associated with a bicuspid aortic valve. Generally, coarctation of the aorta is identified and treated during childhood or early adulthood. If left untreated, this condition can lead to a reduced life expectancy in individuals who have not received treatment. We present a case of a 52-year-old man who complained of chest pain, sputum, and hemoptysis persisting for approximately 2 years. Contrast-enhanced computed tomography (CT) scans revealed the presence of an anterior mediastinal mass, which was later confirmed to be a thymic carcinoma (on histological study). Additionally, an incidental finding of a thoracic aortic coarctation with a well-developed collateral circulation was observed. The discovery of aortic coarctation in adult patients as an incidental finding is rare and particularly uncommon in association with mediastinal or thoracic tumor pathology. Adult and elderly patients with uncorrected coarctation generally have a low survival rate, and the management strategies for such cases are controversial, especially when it is associated to other pathologies. Due to the complexity of therapeutic management and the limited literature available on postsurgical outcomes in these cases, making therapeutic decisions requires a multidisciplinary approach and personalized consideration for each individual case. This approach is necessary to evaluate the risk-benefit ratio and determine the most suitable therapeutic solution.

ACR Appropriateness Criteria® Workup of Noncerebral Systemic Arterial Embolic Source

Noncerebral systemic arterial embolism, which can originate from cardiac and noncardiac sources, is an important cause of patient morbidity and mortality. When an embolic source dislodges, the resulting embolus can occlude a variety of peripheral and visceral arteries causing ischemia. Characteristic locations for noncerebral arterial occlusion include the upper extremities, abdominal viscera, and lower extremities. Ischemia in these regions can progress to tissue infarction resulting in limb amputation, bowel resection, or nephrectomy. Determining the source of arterial embolism is essential in order to direct treatment decisions. This document reviews the appropriateness category of various imaging procedures available to determine the source of the arterial embolism. The variants included in this document are known arterial occlusion in the upper extremity, lower extremity, mesentery, kidneys, and multiorgan distribution that are suspected to be of embolic etiology. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

The effect of postoperative anticoagulation on false lumen patency after surgery for acute type A aortic dissection

Background

Patent false lumen has been shown to have a negative impact on prognosis after surgery for acute type A aortic dissection (ATAAD). We aimed to assess the effect of postoperative anticoagulation on false lumen patency and clinical outcomes in relation to false lumen status.

Methods

Postoperative computed tomographies of 156 patients undergoing ATAAD DeBakey type I surgery were retrospectively evaluated for false lumen patency. The patients were divided into groups determined by anticoagulation treatment at discharge. Uni- and multivariable logistic regression was used for analysing the effect of anticoagulation on the false lumen, and Kaplan–Meier estimates were used to assess the association of a patent false lumen with the incidence of reoperation and long-term survival.

Results

A patent false lumen was present in 81% of the patients. Postoperative anticoagulants were not associated with a patent false lumen (p = 0.48) in univariable analysis. In multivariable analysis, both hemiarch replacement (OR 0.15, CI95% 0.05–0.49, p = 0.001) and the use of betablockers had a protective effect (OR 0.29, CI95% 0.10–0.85, p = 0.023). The Kaplan–Meier estimates for survival and the composite endpoint of survival and freedom from distal reintervention indicated no difference in outcome between patients in regard to anticoagulation treatment (survival p = 0.43, composite p = 0.82) or false lumen status (survival p = 0.21, composite p = 0.09).

Conclusion

This study could not show negative effects from the postoperative use of anticoagulants on false lumen status, nor that false lumen patency was associated with poorer prognosis. A hemiarch procedure was shown to be associated with reduced risk of false lumen patency.

The effect of coarctation degrees on wall shear stress indices

Coarctation of the aorta (CoA) is a congenital tightening of the proximal descending aorta. Flow quantification can be immensely valuable for an early and accurate diagnosis. However, there is a lack of appropriate diagnostic approaches for a variety of cardiovascular diseases, such as CoA. An accurate understanding of the disease depends on measurements of the global haemodynamics (criteria for heart function) and also the local haemodynamics (detailed data on the dynamics of blood flow). Playing a significant role in clinical processes, wall shear stress (WSS) cannot be measured clinically; thus, computation tools are needed to give an insight into this crucial haemodynamic parameter. In the present study, in order to enable the progress of non-invasive approaches that quantify global and local haemodynamics for different CoA severities, innovative computational blueprint simulations that include fluid-solid interaction models are developed. Since there is no clear approach for managing the CoA regarding its severity, this study proposes the use of WSS indices and pressure gradient to better establish a framework for treatment procedures in CoA patients with different severities. This provides a platform for improving CoA therapy on a patient-specific level, in which physicians can perform treatment methods based on WSS indices on top of using a mere experience. Results show how severe CoA affects the aorta in comparison to the milder cases, which can give the medical community valuable information before and after any intervention.

Multimodality imaging assessment of bicuspid aortic valve disease, thoracic aortic ectasia, and thoracic aortic aneurysmal disease

Acute aortic syndromes have extremely high mortality rates and those with aortic dilation are at increased risk for these often catastrophic events. Serial monitoring of patients with aortic dilation is critical to determine the appropriate timing of preventative interventions. The thoracic aorta can be imaged and measured using multiple imaging modalities including transthoracic echocardiography, transesophageal echocardiography, multidetector cardiac computed tomography, and magnetic resonance imaging. There has not been agreement on the specific techniques that should be used to measure thoracic aortic dimensions with each imaging modality, leading to potential errors and challenges in comparing changes in measurements over time. It is critical to understand the current recommendations on thoracic aortic measurements for each imaging modality and cardiovascular imaging specialists need to be explicit about the methods that they have used to derive the thoracic aortic measurements. In those at high risk for aortic pathology, such as those with connective tissue diseases or bicuspid aortic valve, a multimodality imaging strategy incorporating echocardiography including three-dimensional measurements along with cardiac computed tomography or magnetic resonance imaging should be used to establish aortic dimensions and for continued monitoring to avoid progression to acute aortic syndromes.

Low correlation between biometric parameters, cardiovascular risk factors and aortic dimensions by computed tomography coronary angiography

To analyze the relationship between aortic measures and biometric parameters in a large cohort of consecutive patients undergoing computed tomography coronary angiography.1170 patients (717 men/453 women) performing computed tomography coronary angiography for coronary evaluation were retrospectively evaluated. Aortic diameters and areas were measured at reproducible anatomic landmarks, perpendicular to the axis of vessel, at the level of the aortic root (AoR), the sinotubular junction (STJ), and the tubular ascending aorta (TAo). Biometric parameters and cardiovascular risk factors were recorded.The average values of AoR, STJ, and TAo were 35.63 ± 5.00 mm, 30.56 ± 4.82 mm, 35.07 ± 5.84 mm. Hypertension was significantly associated with aortic dimensions.Aortic measures were significantly different between men and women (37.56 ± 4.77 mm vs 32.58 ± 3.68 mm for AoR, 31.88 ± 4.84 mm vs 28.47 ± 3.98 mm for STJ and 35.93 ± 5.86 mm vs 33.70 ± 5.54 mm for TAo) (P < .001) and linearly increased with age. Low Spearman correlation coefficients were found and the correlation of TAo diameters with age displayed the highest values (ρ = 0.372 for male and ρ = 0.373 for female, P < .001). Multiple linear regression analysis models were compared by R. The best model used body surface area (BSA) and age as independent variables and TAo diameter as dependent variable (R = 0.29 for AoR; R = 0.21 for STJ, and R = 0.20 for TAo).In conclusion, in our population low correlation between aortic dimensions and biometric parameters highlights the difficulty of identifying normal ranges, as well as issues related to normalization using conventional biometric parameters.

Guidelines for Cardiovascular Magnetic Resonance Imaging from the Korean Society of Cardiovascular Imaging-Part 2: Interpretation of Cine, Flow, and Angiography Data

Cardiovascular magnetic resonance imaging (CMR) is expected to be increasingly used in Korea due to technological advances and the expanded national insurance coverage of CMR assessments. For improved patient care, proper acquisition of CMR images as well as their accurate interpretation by well-trained personnel are equally important. In response to the increased demand for CMR, the Korean Society of Cardiovascular Imaging (KOSCI) has issued interpretation guidelines in conjunction with the Korean Society of Radiology. KOSCI has also created a formal Committee on CMR guidelines to create updated practices. The members of this committee review previously published interpretation guidelines and discuss the patterns of CMR use in Korea.

Towards non-invasive computational-mechanics and imaging-based diagnostic framework for personalized cardiology for coarctation

Coarctation of the aorta (COA) is a congenital narrowing of the proximal descending aorta. Although accurate and early diagnosis of COA hinges on blood flow quantification, proper diagnostic methods for COA are still lacking because fluid-dynamics methods that can be used for accurate flow quantification are not well developed yet. Most importantly, COA and the heart interact with each other and because the heart resides in a complex vascular network that imposes boundary conditions on its function, accurate diagnosis relies on quantifications of the global hemodynamics (heart-function metrics) as well as the local hemodynamics (detailed information of the blood flow dynamics in COA). In this study, to enable the development of new non-invasive methods that can quantify local and global hemodynamics for COA diagnosis, we developed an innovative fast computational-mechanics and imaging-based framework that uses Lattice Boltzmann method and lumped-parameter modeling that only need routine non-invasive clinical patient data. We used clinical data of patients with COA to validate the proposed framework and to demonstrate its abilities to provide new diagnostic analyses not possible with conventional diagnostic methods. We validated this framework against clinical cardiac catheterization data, calculations using the conventional finite-volume method and clinical Doppler echocardiographic measurements. The diagnostic information, that the framework can provide, is vitally needed to improve clinical outcomes, to assess patient risk and to plan treatment.

Reliability of non-contrast magnetic resonance angiography-derived aortic diameters in Marfan patients: comparison of inner vs. outer vessel wall measurements

Aortic diameter measurements play a crucial role for the indication of aortic root surgery in Marfan patients. However, for magnetic resonance angiography (MRA)-derived measurements, there is no consensus on whether the aortic wall should be included or excluded in the aortic diameter. The purpose of this retrospective study was to compare the reliability of non-contrast bright blood MRA aortic inner-to-inner and outer-to-outer edge measurements in patients with Marfan syndrome. Forty Marfan patients underwent ECG-gated balanced steady-state free-precession MRA of the aorta at 1.5 T. Two readers independently performed inner and outer measurements at different aortic levels. They rated the image quality of the delineation of both inner and outer vessel wall edges on a four-point scale. MRA-derived diameters of the sinuses of Valsalva were compared with echocardiography-derived diameters. Aortic vessel wall delineation score was rated higher at all levels for inner than for outer vessel walls (p < 0.001). Inter- and intraobserver variances of aortic measurements were smaller for inner-to-inner measurements at the sinuses of Valsalva, sinotubular junction and ascending aorta (p < 0.03). There was a difference of 1.1 ± 2.3 mm for inner MRA measurements (p = 0.014) and 6.9 ± 3.1 mm for outer MRA measurements (p < 0.001) when compared to echocardiographic leading-edge measurements. Inner-to-inner vessel wall diameter measurements in non-contrast bright blood MRA provide more reliable diameters when compared to outer-to-outer vessel wall measurements of the aortic root. Therefore, we propose to rely on inner rather than outer aortic wall measurements in non-contrast-MRA when monitoring aortic diameters in patients with Marfan syndrome.

Magnetic resonance multitasking for multidimensional assessment of cardiovascular system: Development and feasibility study on the thoracic aorta

PURPOSE

To develop an MR multitasking-based multidimensional assessment of cardiovascular system (MT-MACS) with electrocardiography-free and navigator-free data acquisition for a comprehensive evaluation of thoracic aortic diseases.

METHODS

The MT-MACS technique adopts a low-rank tensor image model with a cardiac time dimension for phase-resolved cine imaging and a T₂ -prepared inversion-recovery dimension for multicontrast assessment. Twelve healthy subjects and 2 patients with thoracic aortic diseases were recruited for the study at 3 T, and both qualitative (image quality score) and quantitative (contrast-to-noise ratio between lumen and wall, lumen and wall area, and aortic strain index) analyses were performed in all healthy subjects. The overall image quality was scored based on a 4-point scale: 3, excellent; 2, good; 1, fair; and 0, poor. Statistical analysis was used to test the measurement agreement between MT-MACS and its corresponding 2D references.

RESULTS

The MT-MACS images reconstructed from acquisitions as short as 6 minutes demonstrated good or excellent image quality for bright-blood (2.58 ± 0.46), dark-blood (2.58 ± 0.50), and gray-blood (2.17 ± 0.53) contrast weightings, respectively. The contrast-to-noise ratios for the three weightings were 49.2 ± 12.8, 20.0 ± 5.8 and 2.8 ± 1.8, respectively. There were good agreements in the lumen and wall area (intraclass correlation coefficient = 0.993, P < .001 for lumen; intraclass correlation coefficient = 0.969, P < .001 for wall area) and strain (intraclass correlation coefficient = 0.947, P < .001) between MT-MACS and conventional 2D sequences.

CONCLUSION

The MT-MACS technique provides high-quality, multidimensional images for a comprehensive assessment of the thoracic aorta. Technical feasibility was demonstrated in healthy subjects and patients with thoracic aortic diseases. Further clinical validation is warranted.

Standardized image interpretation and post-processing in cardiovascular magnetic resonance - 2020 update : Society for Cardiovascular Magnetic Resonance (SCMR): Board of Trustees Task Force on Standardized Post-Processing

With mounting data on its accuracy and prognostic value, cardiovascular magnetic resonance (CMR) is becoming an increasingly important diagnostic tool with growing utility in clinical routine. Given its versatility and wide range of quantitative parameters, however, agreement on specific standards for the interpretation and post-processing of CMR studies is required to ensure consistent quality and reproducibility of CMR reports. This document addresses this need by providing consensus recommendations developed by the Task Force for Post-Processing of the Society for Cardiovascular Magnetic Resonance (SCMR). The aim of the Task Force is to recommend requirements and standards for image interpretation and post-processing enabling qualitative and quantitative evaluation of CMR images. Furthermore, pitfalls of CMR image analysis are discussed where appropriate. It is an update of the original recommendations published 2013.

Spectrum of multi-detector computed tomography imaging findings of thoracic vascular injuries secondary to blunt chest trauma: Correlation with vascular intervention and patient outcomes

Background

Thoracic vascular injuries following blunt chest trauma are the second leading cause of trauma-related deaths. Multi-detector computed tomography (MDCT) is the imaging modality of choice in detecting these injuries.

Objectives

To determine the spectrum of vascular injuries detected on MDCT imaging in patients who sustained blunt chest trauma, and to assess the various types of management options and patient outcomes.

Method

We retrospectively reviewed archived medical records of polytrauma patients who presented with blunt chest trauma and confirmed vascular injury on MDCT and vascular intervention images between May 2015 and August 2018 at Inkosi Albert Luthuli Central Hospital.

Results

Thirty-nine patients with vascular injury findings were analysed. The injury spectrum comprised: 15 aortic injuries (AI), 19 non-aortic injuries (NAI), 4 combined (AI and NAI) and 1 aorto-venous injury. A majority of males (69%) with an overall mean age of 39 years constituted the study cohort. The commonest injury mechanisms included motor vehicle collisions (61%) and pedestrian accidents (28%); the remaining 11% were shared amongst motorbike accidents or falling from a moving train or a height. The subclavian artery (36%) was the most common anatomical location in the NAI and the frequent imaging finding was vessel occlusion (55%). The most common imaging findings in AI were the indirect signs (20.5%) followed by a grade III injury (15.4%). Six patients with a grade III AI were successfully managed with endovascular repair.

Conclusion

A thorough knowledge of blunt vascular injury spectrums and imaging manifestations is critical when interpreting MDCT scans. Awareness of the mechanism of injury will trigger a high index of suspicion and probe a search for a vascular injury.

"Dark-blood" dual-energy computed tomography angiography for thoracic aortic wall imaging

OBJECTIVES

To assess the capability of a newly developed material decomposition method from contrast-enhanced dual-energy CT images, aiming to better visualize the aortic wall and aortic intramural hematoma (IMH), compared with true non-contrast (TNC) CT.

MATERIALS AND METHODS

Twenty-two patients (11 women; mean age, 61 ± 20 years) with acute chest pain underwent 25 dual-layer non-contrast and contrast-enhanced CT. CT-angiography images were retrospectively processed using two-material decomposition analysis, where we defined the first material as the content of a region of interest placed in the ascending aorta for each patient, and the second material as water. Two independent radiologists assessed the images from the second material termed "dark-blood" images and the TNC images regarding contrast-to-noise ratio (CNR) between the wall and the lumen, diagnostic quality regarding the presence of aortic wall thickening, and the inner/outer vessel wall conspicuity.

RESULTS

Diagnostic quality scores in normal aortic segments were 0.9 ± 0.3 and 2.7 ± 0.6 (p < 0.001) and wall conspicuity scores were 0.7 ± 0.5 and 1.8 ± 0.3 (p < 0.001) on TNC and dark-blood images, respectively. In aortic segments with IMH, diagnostic quality scores were 1.7 ± 0.5 and 2.4 ± 0.6 (p < 0.001) and wall conspicuity scores were 0.7 ± 0.7 and 1.8 ± 0.3 (p < 0.001) on TNC and dark-blood images, respectively. In normal aortic segments, CNRs were 0.3 ± 0.2 and 2.8 ± 0.9 on TNC and dark-blood images, respectively (p < 0.001). In aortic segments with IMH, CNRs were 0.3 ± 0.2 and 4.0 ± 1.0 on TNC and dark-blood images, respectively (p < 0.001).

CONCLUSIONS

Compared with true non-contrast CT, dark-blood material decomposition maps enhance quantitative and qualitative image quality for the assessment of normal aortic wall and IMH.

KEY POINTS

• Current dual-energy CT-angiography provides virtual non-contrast and bright-blood images. • Dark-blood images represent a new way to assess the vascular wall structure with dual-energy CT and can improve the lumen-to-wall contrast compared with true non-contrast CT. • This dual-energy CT material decomposition method is likely to improve contrast resolution in other applications as well, taking advantage of the high spatial resolution of CT.

Gadobutrol: A Review in Contrast-Enhanced MRI and MRA

Intravenous gadobutrol [Gadovist^™ (EU); Gadavist^® (USA)] is a second-generation, extracellular non-ionic macrocyclic gadolinium-based contrast agent (GBCA) that is approved for use in paediatric (including term neonates) and adult patients undergoing diagnostic contrast-enhanced (CE) MRI for visualization of pathological lesions in all body regions or for CE MRA to evaluate perfusion and flow-related abnormalities. Its unique physicochemical profile, including its high thermostability and proton relaxation times, means that gadobutrol is formulated at twice the gadolinium ion concentration of other GBCAs, resulting in a narrower bolus and consequently, improved dynamic image enhancement. Based on >  20 years of experience in the clinical trial and real-world settings (>  50 million doses) and its low risk for developing nephrogenic systemic fibrosis (NSF), gadobutrol represents an effective and safe diagnostic GBCA for use in CE MRI and MRA to visualize pathological lesions and vascular perfusion and flow-related abnormalities in all body regions in a broad spectrum of patients, including term neonates and other paediatric patients, young and elderly adult patients, and those with moderate or severe renal or hepatic impairment or cardiovascular (CV) disease.

MR Imaging of Thoracic Aortic Disease

A number of congenital defects and acquired disease processes affect the thoracic aorta, and traditionally, computed tomography (CT) has been the mainstay of imaging, especially in evaluation of the acute aorta. However, recent advances in magnetic resonance (MR) imaging such as electrocardiographically (ECG) triggered breath-hold sequences and ultrafast 3-dimensional MR angiography (MRA) are bringing MR imaging to the forefront of imaging of the thoracic aorta. By providing high-resolution morphological imaging and sophisticated vascular flow analysis for functional data, this modality can provide a comprehensive, reproducible evaluation of the thoracic aorta. In this review, we discuss the role of MR imaging in the evaluation of thoracic aorta pathology along with pertinent examples of aortic abnormalities.

Preserved Myocardial Deformation after Successful Coarctation Repair: A CMR Feature-Tracking Study

Arterial vasculopathy and residual aortic obstruction can lead to left ventricular (LV) dysfunction in patients with coarctation of the aorta (CoA) related to adverse ventriculo-arterial coupling. This study aimed to investigate potential differences in LV myocardial deformation indices between repaired CoA patients and healthy controls. Twenty-two CoA patients (age 30 ± 10.6 years) after surgical repair (n = 12) or balloon angioplasty (BA) (n = 10) without residual stenosis, between 3 months and 16 years of age with > 10 years follow-up were compared to 22 healthy age- and gender-matched controls (age 30 ± 3.8 years). Cardiac magnetic resonance feature tracking (CMR-FT) was used for LV longitudinal-, circumferential-, and rotational deformation indices. Global systolic LV function was preserved in CoA patients (LV ejection fraction 58 ± 4.8 vs. 60 ± 6.8%, p = 0.56) when compared to controls, with normal LV dimensions and mass (p > 0.05). Twelve CoA patients (55%) were hypertensive, of whom 4 were on anti-hypertensive medication. LV global longitudinal strain was preserved in the four-chamber (- 18 ± 4.4 vs. - 16 ± 4.7%, p = 0.06) and two-chamber (- 22 ± 5.1 vs. - 20 ± 6.0%, p = 0.22) orientations in CoA patients. Global circumferential strain was preserved at basal (- 29 ± 4.1 vs. - 28 ± 4.8%, p = 0.43), mid-ventricular (- 27 ± 4.2 vs. - 25 ± 3.0%, p = 0.09), and apical levels (- 35 ± 7.8 vs. - 32 ± 34.9%, p = 0.32). No differences were found in global torsion (2.4 ± 1.3° vs. 2.0 ± 1.4°/cm, p = 0.28), twist (14 ± 5.8° vs. 12 ± 6.3°, p = 0.34), and recoil rate (- 17 ± 9.7° vs. - 17 ± 7.1°/cm s, p = 0.97). Analysis of intra-observer variability demonstrated good reproducibility for all CMR deformation indices. Global and rotational myocardial deformation indices are preserved in CoA patients long-term after repair without residual stenosis, despite a high incidence of hypertension.

Non-contrast MR angiography at 1.5 Tesla for aortic monitoring in Marfan patients after aortic root surgery

BACKGROUND

Contrast-enhanced cardiovascular magnetic resonance angiography (CE-CMRA) is the established imaging modality for patients with Marfan syndrome requiring life-long annual aortic imaging before and after aortic root replacement. Contrast-free CMRA techniques avoiding side-effects of contrast media are highly desirable for serial imaging but have not been evaluated in the postoperative setup of Marfan patients. The purpose of this study was to assess the feasibility of non-contrast balanced steady-state free precession (bSSFP) magnetic resonance imaging for aortic monitoring of postoperative patients with Marfan syndrome.

METHODS

Sixty-four adult Marfan patients after aortic root replacement were prospectively included. Fourteen patients (22%) had a residual aortic dissection after surgical treatment of type A dissection. bSSFP imaging and CE-CMRA were performed at 1.5 Tesla. Two radiologists evaluated the images regarding image quality (1 = poor, 4 = excellent), artifacts (1 = severe, 4 = none) and aortic pathologies. Readers measured the aortic diameters at defined levels in both techniques. Statistics included observer agreement for image scoring and diameter measurements and ROC analyses for comparison of the diagnostic performance of bSSFP and CE-CMRA.

RESULTS

Both readers observed no significant differences in image quality between bSSFP and CE-CMRA and found a median image quality score of 4 for both techniques (all p > .05). No significant differences were found regarding the frequency of image artifacts in both sequences (all p > .05). Sensitivity and specificity for detection of aortic dissections was 100% for both readers and techniques. Compared to bSSFP imaging, CE-CMRA resulted in higher diameters (mean bias, 0.9 mm; p < .05). The inter-observer biases of diameter measurements were not significantly different (all p > .05), except for the distal graft anastomosis (p = .001). Using both techniques, the readers correctly identified a graft suture dehiscence with aneurysm formation requiring surgery.

CONCLUSION

Unenhanced bSSFP CMR imaging allows for riskless aortic monitoring with high diagnostic accuracy in Marfan patients after aortic root surgery.

Diagnosis, imaging and clinical management of aortic coarctation

Coarctation of the aorta (CoA ) is a well-known congenital heart disease (CHD) , which is often associated with several other cardiac and vascular anomalies, such as bicuspid aortic valve (BAV), ventricular septal defect, patent ductus arteriosus and aortic arch hypoplasia. Despite echocardiographic screening, prenatal diagnosis of C o A remains difficult. Most patients with CoA present in infancy with absent, delayed or reduced femoral pulses, a supine arm-leg blood pressure gradient (> 20 mm Hg), or a murmur due to rapid blood flow across the CoA or associated lesions (BAV). Transthoracic echocardiography is the primary imaging modality for suspected CoA. However, cardiac magnetic resonance imaging is the preferred advanced imaging modality for non-invasive diagnosis and follow-up of CoA. Adequate and timely diagnosis of CoA is crucial for good prognosis, as early treatment is associated with lower risks of long-term morbidity and mortality. Numerous surgical and transcatheter treatment strategies have been reported for CoA. Surgical resection is the treatment of choice in neonates, infants and young children. In older children (> 25 kg) and adults, transcatheter treatment is the treatment of choice. In the current era, patients with CoA continue to have a reduced life expectancy and an increased risk of cardiovascular sequelae later in life, despite adequate relief of the aortic stenosis. Intensive and adequate follow-up of the left ventricular function, valvular function, blood pressure and the anatomy of the heart and the aorta are , therefore, critical in the management of CoA. This review provides an overview of the current state-of-the-art clinical diagnosis, diagnostic imaging algori thms, treatment and follow-up of patients with CoA.

Infantile Aortic Coarctation in an Adult with Heart Failure

OBJECTIVE

The aim of this case report is to highlight the importance of excluding aortic coarctation in a patient with a bicuspid aortic valve.

CLINICAL PRESENTATION AND INTERVENTION

A 56-year-old woman with hypertension was admitted complaining of progressive dyspnea. Transthoracic echocardiography showed a calcified, bicuspid aortic valve with severe stenosis. Aortography revealed the presence of severe narrowing of the aorta between the carotid and subclavian arteries. The patient was referred for cardiovascular surgery in which successful aortic valve replacement and aortic correction were performed.

CONCLUSION

This case report shows an uncommon finding of infantile aortic coarctation in an adult patient admitted with heart failure.

Imaging the posterior mediastinum: a multimodality approach

The posterior mediastinum contains several structures that can produce a wide variety of pathologic conditions. Descending thoracic aorta, esophagus, azygos and hemiazygos veins, thoracic duct, lymph nodes, adipose tissue, and nerves are all located in this anatomical region and can produce diverse abnormalities. Although chest radiography may detect many of these pathologic conditions, computed tomography and magnetic resonance are the imaging modalities of choice for further defining the relationship of posterior mediastinal lesions to neighboring structures and showing specific imaging features that narrow the differential diagnosis. This review emphasizes modality-related answers to morphologic questions, which provide precise diagnostic information.

Combined blood pool and extracellular contrast agents for pediatric and young adult cardiovascular magnetic resonance imaging

BACKGROUND

A comprehensive cardiac magnetic resonance (cardiac MR) study including both late gadolinium enhancement (LGE) and MR angiography may be indicated for patients with a history of acquired or congenital heart disease.

OBJECTIVE

To study the novel use of an extracellular agent for assessment of LGE combined with a blood pool contrast agent for detailed MR angiography evaluation to yield a comprehensive cardiac MR study in these patients.

MATERIALS AND METHODS

We reviewed clinical cardiac MR studies utilizing extracellular and blood pool contrast agents and noted demographics, clinical data and adverse events. We rated LGE image quality and MR angiography image quality for each vascular segment and calculated inter-rater variability. We also quantified contrast-to-noise ratio (CNR).

RESULTS

Thirty-three patients (mean age 13.9 ± 3 years) received an extracellular contrast agent (10 gadobenate dimeglumine, 23 gadopentetate dimeglumine) and blood pool contrast agent (33 gadofosveset trisodium). No adverse events were reported. MRI indications included Kawasaki disease (8), cardiomyopathy and coronary anatomy (15), repaired congenital heart disease (8), and other (2). Mean LGE quality was 2.6 ± 0.6 with 97% diagnostic imaging. LGE quality did not vary by type of contrast agent given (P = 0.07). Mean MR angiography quality score was 4.7 ± 0.6, with high inter-rater agreement (k = 0.6-0.8, P < 0.002). MR angiography quality did not vary by type of contrast agent used (P = 0.6).

CONCLUSION

Cardiac MR studies utilizing both extracellular and blood pool contrast agents are feasible and safe and provide excellent-quality LGE and MR angiography images. The use of two contrast agents allows for a comprehensive assessment of both myocardial viability and vascular anatomy during the same exam.

Is ECG triggering for motion artefact reduction in dual-source CT angiography of the ascending aorta still required with high-pitch scanning? The role of ECG-gating in high-pitch dual-source CT of the ascending aorta

OBJECTIVE:

To compare electrocardiographic (ECG)-triggered high-pitch (HP) dual-source CT angiography (CTA) with non-ECG-triggered HP CTA of the aorta, particularly the ascending aorta, with regard to image quality, motion artefacts, contrast-to-noise ratio (CNR), signal-to-noise ratio (SNR) and radiation dose.

METHODS:

59 consecutive patients who had been referred for CTA for known or suspected aortic disease, previous aortic intervention or planned transapical or transfemoral aortic valve implantation were prospectively included. Patients underwent CTAs with HP, using a dual-source CTA system, with [control group (Group A); n = 30] or without (Group B; n = 29) ECG triggering after randomization. For evaluation, image quality and a motion artefact score (MAS) were assessed in a blinded fashion at different predefined anatomic regions. CNR and SNR were measured at the same levels. Radiation dose estimates and contrast enhancement were compared between the two groups.

RESULTS:

There were no significant differences for image quality and MAS. The intra-arterial contrast resolution was significantly higher at the level of the aortic arch and descending aorta in the non-triggered group (CNR values, p = 0.002-0.018). No significant differences in the radiation dose were found.

CONCLUSION:

Non-triggered HP dual-source CTA provided comparable results with regard to image quality, MAS, CNR, SNR and radiation doses compared with ECG-triggered HP CTA. Therefore, ECG triggering of the ascending aorta might be obviated when HP scanning is available.

ADVANCES IN KNOWLEDGE:

HP dual-source CTA might obviate ECG triggering in the ascending aorta. Non-triggered HP CTA of the ascending aorta provides an excellent image quality.

MDCT evaluation of acute aortic syndrome (AAS)

Non-traumatic acute thoracic aortic syndromes (AAS) describe a spectrum of life-threatening aortic pathologies with significant implications on diagnosis, therapy and management. There is a common pathway for the various manifestations of AAS that eventually leads to a breakdown of the aortic intima and media. Improvements in biology and health policy and diffusion of technology into the community resulted in an associated decrease in mortality and morbidity related to aortic therapeutic interventions. Hybrid procedures, branched and fenestrated endografts, and percutaneous aortic valves have emerged as potent and viable alternatives to traditional surgeries. In this context, current state-of-the art multidetector CT (MDCT) is actually the gold standard in the emergency setting because of its intrinsic diagnostic value. Management of acute aortic disease has changed with the increasing realization that endovascular therapies may offer distinct advantages in these situations. This article provides a summary of AAS, focusing especially on the MDCT technique, typical and atypical findings and common pitfalls of AAS, as well as recent concepts regarding the subtypes of AAS, consisting of aortic dissection, intramural haematoma, penetrating atherosclerotic ulcer and unstable aortic aneurysm or contained aortic rupture. MDCT findings will be related to pathophysiology, timing and management options to achieve a definite and timely diagnostic and therapeutic definition. In the present article, we review the aetiology, pathophysiology, clinical presentation, outcomes and therapeutic approaches to acute aortic syndromes.

Pediatric Chest MR Imaging: Sedation, Techniques, and Extracardiac Vessels

Thoracic MR imaging in the pediatric population provides unique challenges requiring tailored protocols and a practical approach to pediatric issues, such as patient motion and sedation. Concern regarding the use of ionizing radiation in the pediatric population has continued to advance the use of MR imaging despite these challenges. This article provides a practical approach to thoracic vascular MR imaging with special attention paid to pediatric-specific issues such as sedation. Thoracic vascular anatomy and pathology are discussed with an emphasis on protocols that can facilitate accurate diagnosis.

Advances in the diagnosis of acute aortic syndromes: Role of imaging techniques

Aortic diseases include a wide range of pathological conditions: aortic aneurysms, pseudoaneurysms, acute aortic syndromes, atherosclerotic and inflammatory conditions, genetic diseases and congenital anomalies. Acute aortic syndromes have acute onset and may be life-threatening. They include aortic dissection, intramural haematoma, penetrating aortic ulcer and traumatic aortic injury. Pain is the common denominator to all acute aortic syndromes. Pain occurs regardless of age, gender and other associated clinical conditions. In this review, we deal with the main findings in the clinical setting and the most recent indications for diagnostic imaging, which are aimed to start an appropriate treatment and improve the short- and long-term prognosis of these patients.

CT and MRI of aortic coarctation: pre- and postsurgical findings

OBJECTIVE. The purpose of this article is to summarize the roles of CT and MRI in the diagnosis and follow-up of patients with aortic coarctation. CONCLUSION. Aortic coarctation is a common congenital heart disease accounting for approximately 6-8% of congenital heart defects. Despite its deceptively simple anatomic presentation, it is a complex medical problem with several associated anatomic and physiologic abnormalities. CT and MRI may provide very accurate information of the coarctation anatomy and other associated cardiac abnormalities.

MRI in adult patients with aortic coarctation: diagnosis and follow-up

Aortic coarctation is a disease that usually presents in infancy; however, a proportion of patients present for the first time in adulthood. These lesions generally require repair with either surgery or interventional techniques. The success of these techniques means that increasing numbers of patients are presenting for follow-up imaging in adulthood, whether their coarctation was initially repaired in infancy or as adults. Thus, the adult presenting to the radiologist for assessment of possible coarctation or follow-up of coarctation repair is not an uncommon scenario. In this review, we present details of the MRI protocols and MRI findings in these patients so that a confident and accurate assessment can be made.

CT dose reduction using prospectively triggered or fast-pitch spiral technique employed in cardiothoracic imaging (the CT dose study)

OBJECTIVES

To establish current radiation dose levels with contemporary scanners capable of prospectively triggered or high-pitch spiral scan modes to previous generation scanners among patients evaluated for coronary artery disease, pulmonary embolism, aortic disease, and "triple rule out" in a large population of patients at multiple centers.

BACKGROUND

Previous small-scale studies with carefully controlled scan protocols report that CT scanners that facilitate prospectively triggered scanning and provide high-pitch spiral CT scan modes drastically lower radiation doses. However, diagnostic reference levels should be selected by medical bodies on the basis of large surveys of representative sites and reviewed at appropriate time intervals.

METHODS

Scan data including dose and image quality parameters were collected retrospectively from 64 slice scanners (control) and prospectively after sites installed 128-slice dual-source scanners with high-pitch capability (study). Protocol selection was purposely not specified to survey "real world" results. Blinded quantitative image analysis was performed on every fifth scan.

RESULTS

From April 2011 to March 2012, 2085 patients at 9 sites completed the study: 1051 coronary artery disease (509 control, 542 study), 528 pulmonary embolism (267 control, 261 study), 419 aortic disease (268 control, 151 study), and 87 triple rule out (53 control, 34 study). There was a significant reduction in median dose-length product (DLP) from 669 mGy ∙ cm (interquartile range [IQR]: 419-1026 mGy ∙ cm) in the control group to 260 mGy ∙ cm (IQR: 159-441 mGy ∙ cm) in the study group, a reduction by 61% (P < .0001) and was lower in all categories. No significant differences were noted in image quality.

CONCLUSION

Use of advanced scanners facilitating prospectively triggered or high-pitch spiral scan modes results in marked dose reduction across a variety of cardiovascular studies, with no compromise in image quality. These findings may contribute to new target dose recommendations in societal guidelines.

Gadobutrol: a review of its use for contrast-enhanced magnetic resonance imaging in adults and children

Since the introduction of the first gadolinium-based contrast agent (GBCA) approximately 25 years ago, magnetic resonance imaging (MRI) using GBCAs has revolutionized diagnostic and follow-up imaging of pathological lesions, with clinical applications expanded to encompass almost all fields of medicine. Intravenous gadobutrol (Gadovist™ [EU]; Gadavist(®) [USA]) is a second-generation extracellular non-ionic macrocyclic GBCA that is used in patients undergoing diagnostic contrast-enhanced MRI for visualization of pathological lesions in the CNS and all other body regions or for contrast-enhanced magnetic resonance angiography (MRA) to evaluate perfusion and flow-related abnormalities. Its unique physicochemical profile, along with the high thermostability of macrocyclic GBCAs, means gadobutrol is formulated at twice the gadolinium ion concentration of other currently licensed GBCAs. This reduces the injection volume and provides a narrower bolus, thereby improving image enhancement. Based on extensive clinical experience in a broad range of patients, including paediatric and adult patients (younger and elderly adults), and those with moderate to severe hepatic or renal impairment or cardiovascular disorders, gadobutrol is an effective and generally well tolerated extracellular GBCA for patients undergoing diagnostic contrast-enhanced MRI and contrast-enhanced MRA. As with all macrocyclic GBCAs, the potential for gadobutrol to cause nephrogenic systemic fibrosis appears to be lower than with linear GBCAs.

Standardized image interpretation and post processing in cardiovascular magnetic resonance: Society for Cardiovascular Magnetic Resonance (SCMR) board of trustees task force on standardized post processing

With mounting data on its accuracy and prognostic value, cardiovascular magnetic resonance (CMR) is becoming an increasingly important diagnostic tool with growing utility in clinical routine. Given its versatility and wide range of quantitative parameters, however, agreement on specific standards for the interpretation and post-processing of CMR studies is required to ensure consistent quality and reproducibility of CMR reports. This document addresses this need by providing consensus recommendations developed by the Task Force for Post Processing of the Society for Cardiovascular MR (SCMR). The aim of the task force is to recommend requirements and standards for image interpretation and post processing enabling qualitative and quantitative evaluation of CMR images. Furthermore, pitfalls of CMR image analysis are discussed where appropriate.