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Strongly correlated materials can display exotic quantum phenomena relevant to the emergence of quantum technologies. Yet, many questions have remained open because of the difficulty in modelling the underlying physics beyond a few lattice sizes. Therefore, a continuing effort has been made to develop quantum simulation platforms, where these many-body states can be artificially emulated with a great degree of control in bespoke hardware implementations. This thesis focuses on the use of dopant-based atomic-scale devices in silicon to build artificial quantum matter probed by a low-temperature scanning tunnelling microscope (STM). We combine STM hydrogen lithography with phosphine doping for the placement of phosphorus donors in our silicon devices with atomic precision and perform spatially resolved measurements using the STM tip. We first establish the experimental platform by characterising strongly correlated states found in single and pairs of quantum dots made of a few donors each. Using these building blocks, we create devices based on dimerised chains to perform an analogue quantum simulation of the Su-Schrieffer-Hegger model, a topological quantum system that classical computers cannot solve effectively. As a preliminary result, we demonstrate the formation of 25 nm-long electronic bands in chains of 5 and 7 sites. These results demonstrate the viability of using silicon as a base for the realisation of Fermi-Hubbard analogue quantum simulators inside a low-temperature STM, with the tip as a tuneable local probe.

We study the effects of electron-electron interactions on the charge excitation spectrum of the spinful Su-Schrieffer-Heeger (SSH) model, a prototype of a 1D bulk obstructed topological insulator. In view of recent progress in the fabrication of dopant-based quantum simulators we focus on experimentally detectable signatures of interacting topology in finite lattices. To this end we use Lanczos-based exact diagonalization to calculate the single-particle spectral function in real space which generalizes the local density of states to interacting systems. Its spatial and spectral resolution allows for the direct investigation and identification of edge states. By studying the non-interacting limit, we demonstrate that the topological in-gap states on the boundary are robust against both finite-size effects as well as random bond and onsite disorder which suggests the feasibility of simulating the SSH model in engineered dopant arrays in silicon. While edge excitations become zero-energy spin-like for any finite interaction strength, our analysis of the spectral function shows that the single-particle charge excitations are gapped out on the boundary. Despite the loss of topological protection we find that these edge excitations are quasiparticle-like as long as they remain within the bulk gap. Above a critical interaction strength of $U_c\approx 5 t$ these quasiparticles on the boundary loose their coherence which is explained by the merging of edge and bulk states. This is in contrast to the many-body edge excitations which survive the limit of strong coupling, as established in the literature. Our findings show that for moderate repulsive interactions the non-trivial phase of the interacting SSH model can be detected through remnant signatures of topological single-particle states using single-particle local measurement techniques such as scanning tunneling spectroscopy., 16 pages + 13 figures; v2: final version

Anatomical delineation of the holocephalan palatoquadrate has proven to be difficult and, so, has been an extensively debated topic as it relates to the evolutionary derivation of jaws, modes of jaw suspension, and the interrelationships of the hondrichthyes (Elasmobranchii and Holocephali). Embryological analyses of the chimaerid jaw and cranium are presented to provide an anatomical description of the palatoquadrate in modern chimaerids. The palatoquadrate fuses, anteriorly, to the nasal capsule early in development. This marks the first point of contact between the mandibular arch and cranium. Orbitonasal canal foramina delineate the dorsal palatoquadrate margin. The posteriormost margin is marked by fusion of the upper jaw with trabecular and parachordal cartilages in the region of the efferent eudobranchial artery foramen and by a suborbitally positioned basitrabecular cartilage. This basitrabecula generates a subocular shelf as it fuses medially to the parachordal cartilage and posteriorly to the postorbital wall and cranial otic process. The results of these analyses are related to morphological studies of Paleozoic chondrichthyan fishes, particularly the autodiastylic paraselachians that represent morphological intermediates to selachians and holocephalans. The paraselachian basitrabecular, which was mechanically fundamental to stabilizing the free autodiastylic upper jaw and a hyoid operculum, is shown to correlate with the suborbital basitrabecular of today's chimaerids. Further analyses of both extant and fossil data permit us to conclude that the primordial chondrichthyan palatoquadrate did not extend posteriorly to include a palatoquadrate-derived otic process. Rather, the posteriormost extent of this element is primitively found within the limits of the orbit and is demarcated by the highly conserved basitrabecular element. The collective analyses support autodiastyly as the ancestral condition from which all fundamental suspensorial states are derived. J. Morphol. 239:45-59, 1999. © 1999 Wiley-Liss, Inc.

Introduction: Patients with absent pulmonary valve syndrome often present early with airway compression from aneurysmal pulmonary arteries. This study reviews our experience in managing absent pulmonary valve syndrome in later presenting children, and techniques used for managing airway compression. Methods: This study is a retrospective chart review of all patients who underwent repair of absent pulmonary valve syndrome from 2000 to 2012 at our institution. The primary endpoints were post-operative bronchoscopic and clinical evidence of persistent airway compression and need for reinterventions on the pulmonary arteries. Results: A total of 19 patients were included during the study period. The mean age at repair was 4.1±3.0 years (range 10 months–11 years). In all, seven patients had pre-operative bronchoscopic evidence of airway compression, which was managed by pulmonary artery reduction plasty in four patients and Lecompte manoeuvre in three patients. There were no peri-operative deaths. In patients with pulmonary artery plasty, two had no post-operative airway compression, one patient had improved compression, and one patient had unchanged compression. In patients managed with a Lecompte manoeuvre, two patients had no or trivial airway compression and one had improved compression. There were six late reinterventions or reoperations on the pulmonary arteries – two out of four in the pulmonary artery plasty group and one out of three in the Lecompte group. Conclusions: Most late-presenting patients with absent pulmonary valve syndrome do not have airway compression. Either pulmonary artery reduction plasty or the Lecompte manoeuvre can relieve proximal airway compression, without a significantly different risk of pulmonary artery reintervention between techniques.

A 2-year-old boy was referred for cyanosis and clinical heart failure. Transthoracic echocardiography showed Tetralogy of Fallot (TOF) with a large malalignment type ventricular septal defect (VSD) and features typical of absent pulmonary valve syndrome (APVS). There was severe pulmonary stenosis (Sten) (peak systolic gradient of 85 mmHg) with diastolic regurgitation, …

Despite intense effort, obesity is still rising throughout the world. Links between obesity and cardiovascular diseases are now well established. Most of the cardiovascular changes related to obesity can be followed by magnetic resonance imaging (MRI) or by magnetic resonance spectroscopy (MRS). In particular, we will see in this review that MRI/MRS is extremely well suited to depict (1) changes in cardiac mass and function, (2) changes in stroke volume, (3) accumulation of fat inside the mediastinum or even inside the cardiomyocytes, (4) cell viability and (5) molecular changes during early cardiovascular diseases.

Congenital left ventricular aneurysm is an uncommon cardiac malformation. A 9-year-old boy with complaints of dyspnea and palpitation was diagnosed with a left ventricular aneurysm originating from the left ventricle free wall. Aneurysm resection and endoventricular patch repair was performed. Postoperative follow-up was uncomplicated and follow-up echocardiographs showed normal left ventricular contractility.

Introduction: Anomalies of the aortic arch are frequent congenital malformations, which rarely form partial or complete vascular rings. A rare form of vascular ring is the encircling, or circumflex, aortic arch.Case Report: A 19-month-old boy, with no respiratory symptoms, was referred for ventricular septal defect (VSD) repair. Cardiac magnetic resonance imaging and echocardiography confirmed the perimembranous VSD, a bicuspid aortic valve with normal function, and showed a right-sided ascending aorta, bifurcating to the left behind the esophagus and trachea above the tracheal bifurcation, with a left-sided descending aorta, a left ligamentum arteriosum and aberrant left subclavian artery, realizing a circumflex aortic arch. The child underwent successful VSD repair and ligamentum arteriosum division, with an uneventful postoperative course.Conclusions: Previous reports have described the association of circumflex aortic arch with VSD, but there is no previous report of its association with VSD and bicuspid aortic valve. Patients are usually symptomatic either preoperatively, or after VSD repair. For this reason, division of the ligamentum arteriosum, to open the vascular ring and free the trachea and esophagus from compression, should be performed in patients undergoing cardiac surgery for associated malformations.

Atresia of the aortic arch is a rare congenital heart defect with a high mortality when associated with other intracardiac defects. Cardiac magnetic resonance (CMR) provides the exact anatomy of the aortic arch and collateral circulation and is useful to diagnose-associated aortic arch anomalies. This report describes the case of a 4-year-old child with atresia of the aortic arch, referred to our institution with the diagnosis of aortic coarctation and bicuspid aortic valve. On clinical exam, the femoral pulses were not palpable and there was a significant differential blood pressure between the upper and lower limbs. The echocardiography showed a severely stenotic bicuspid aortic valve but was limited for the exact description of the aortic arch. CMR showed absence of lumen continuity between the ascending and descending aorta distal to the left subclavian artery, extending over 5 mm, with the presence of a bend in the arch and diverticulum on either side of the zone of discontinuity, suggesting the diagnosis atresia of the aortic arch rather than coarctation or interruption. The patient benefited from a successful surgical commissurotomy of the aortic valve and reconstruction of the aortic arch with a homograft. The post-operative CMR confirmed the good surgical result. This case emphasizes the utility of CMR to provide good anatomical information to establish the exact diagnosis and the operative strategy.

Purpose To estimate the effect of the inflow effect on the arterial input function in vivo in cardiac and renal MR perfusion imaging using fast gradient echo (GRE) sequences and contrast media. Materials and Methods The MR exam protocol was designed to acquire images at different phases of the cardiac cycle. The arterial input was thus influenced by various blood flow velocities. Results It was found that the inflow effect was negligible in the left ventricle of the heart, while it was significantly higher in the aorta for the kidney perfusion measurement. This was principally due to the higher through-the-plane component of the blood flow velocity in the aorta than in the left ventricle. Conclusion The inflow effect can be neglected in the heart cavity, but should be taken into account in renal perfusion. J. Magn. Reson. Imaging 2003;18:372–376. © 2003 Wiley-Liss, Inc.

This study reports on the first use of high flip angle and radio-frequency (RF) spoiling in T1-prepared fast acquisition in steady state (FAST) sequence for myocardial perfusion in patients. T1 dynamic range was measured in vitro with a FAST, an RF FAST and a snapshot fast low-angle shot (FLASH) sequences with a 90 degrees flip angle. Myocardial perfusion was then measured twice in 6 patients during the same MR session. The RF FAST and FLASH, but not the FAST sequence, demonstrated an extended T1 dynamic range; however, the FLASH images were degraded by artifacts not present on the RF FAST images. The myocardial perfusion indices K1 (first-order transfer constant from the blood to the myocardium for the Gd-DTPA) and Vd (distribution volume of Gd-DTPA in myocardium) did not differ significantly between the two injections. K1 was 0.48+/-0.12 ml/min g(-1) and Vd was 12.5+/-2.9%. With an extended T1 dynamic range and the sensitivity required for myocardial perfusion quantification, the RF FAST sequence with a 90 degrees flip angle outperformed the snapshot FLASH sequence in terms of image quality and the FAST sequence in terms of contrast dynamic range.

Evaluation of valve disease has changed significantly with the development of color Doppler echocardiography. Nevertheless, this technique has limitations, particularly in the assessment of valvular regurgitation. MR imaging, with its ability to provide three-dimensional morphologic data, dynamic cine information, and functional evaluation with flow-sensitive techniques, can be envisioned as a complementary noninvasive modality, able to provide the complete information required for planning therapeutic options. With MR imaging, qualitative as well as accurate and reproducible quantitative information such as volume measurements, cardiac function, and flow velocity profiles are unique for the evaluation of the severity of valve disease. This article reviews the different MR imaging techniques used in assessing valvular heart disease and discusses the advantages and limitations of these techniques in current clinical applications in comparison with classical imaging methods.

Unintentional intraarterial injections are rare but may have devastating consequences. No consensus on treatment has been established owing to the wide variety of possible injected substances, incomplete understanding of the underlying pathophysiology, and the absence of case-controlled, prospective human studies. The aim of the present study and literature review was to evaluate the benefit of intraarterial thrombolysis combined with systemic anticoagulation therapy when an artery of the upper extremity is accidentally punctured and ischemia of the hand ensues.

Magnetic resonance (MR) imaging is rapidly gaining acceptance as an accurate, reproducible, noninvasive method for optimal assessment of structural and functional parameters in patients with valvular heart disease. The severity of valvular regurgitation can be evaluated with cine gradient-echo MR imaging, which allows measurement of the area of the signal void corresponding to the abnormal flow jet. Alternatively, this modality can be used to obtain ventricular volumetric measurements and calculate the regurgitant fraction, or velocity-encoded cine (VEC) MR imaging can be used to quantify regurgitant blood flow. The severity of valvular stenosis can be determined by evaluating the flow jet and associated findings with either modality or by using VEC MR imaging to calculate the transvalvular pressure gradient and valve area. Dynamic MR imaging allows accurate assessment of ventricular function and comprehensive evaluation of pathophysiologic changes. In addition, good interstudy reproducibility suggests a role for VEC MR imaging in assessing the effects of therapeutic intervention and monitoring regurgitant fraction, thereby helping in surgical planning and the prevention of ventricular dysfunction. With greater cost-effectiveness and the increasing availability of new hardware and more advanced techniques, MR imaging will become a routine procedure in valvular heart disease.

The optimal regime of antithrombotic prophylaxis for patients undergoing total knee arthroplasty (TKA) has not been established. Many surgeons employ intermittent pneumatic compression while others use low-molecular-weight heparins (LMWH) which were primarily developed for total hip arthroplasty. We compared the efficacy and safety of these two techniques in a randomised study with blinded assessment of the endpoint by phlebography. We randomised 130 patients, scheduled for elective TKA, to receive one daily subcutaneous injection of nadroparin calcium (dosage adapted to body-weight) or continuous intermittent pneumatic compression of the foot by means of the arteriovenous impulse system. A total of 108 patients (60 in the LMWH group and 48 in the mechanical prophylaxis group) had phlebography eight to 12 days after surgery. Of the 47 with deep-vein thrombosis, 16 had received LMWH (26.7%, 95% CI 16.1 to 39.7) and 31, mechanical prophylaxis (64.6%, 95% CI 49.5 to 77.8). The difference between the two groups was highly significant (p < 0.001). Only one patient in the LMWH group had severe bleeding. We conclude that one daily subcutaneous injection of calcium nadroparin in a fixed, weight-adjusted dosage scheme is superior to intermittent pneumatic compression of the foot for thromboprophylaxis after TKA. The LMWH scheme was also safe.

Pseudoaneurysms of visceral arteries are uncommon but well-characterized vascular abnormalities, usually provoked by intraabdominal inflammatory processes such as pancreatitis or cholecystitis, or by surgical trauma. However, pseudoaneurysms of the cystic artery are rare. They complicate cholecystitis or cholecystectomy, and manifest as hemobilia as they rupture into the biliary tree. The advent of transcatheter embolization techniques has begun to allow minimally invasive treatment of these life-threatening complications. Transcatheter embolization can be performed using several types of material, such as synthetic occlusive emulsions, gelatin sponges or other particles, or metallic microcoils. Microcoils are small metallic helical particles, made of stainless-steel, platinum, or tungsten. Super-selective catheterization of an artery and release of microcoils causes the vessel to thrombose and allows control of bleeding.

The effectiveness of new diagnostic tools for suspected pulmonary embolism (PE), such as clinical probability assessment, plasma D-dimer (DD) measurement and lower limb venous compression ultrasonography (US), has not been specifically studied in patients with a suspected PE occurring during hospital stay. This study applied a sequential, decision analysis-based strategy adding these instruments to a ventilation/perfusion lung scan in a cohort of 114 consecutive inpatients clinically suspected of PE in order to establish in how many patients a pulmonary angiogram could thereby be avoided. A definitive diagnosis could be established by the noninvasive protocol in 61% of these patients: normal/near-normal lung scan, 14%; high probability lung scan, 19%; clinical probability combined with lung scan result, 18%; and US, 8%. Specificity of DD was only 7% and contributed to the exclusion of PE in only two patients. Pulmonary angiography was required in 39% of patients. The 3-month thromboembolic risk in patients in whom PE was excluded by the diagnostic process was 0% (95% confidence interval 0-4.9%). In conclusion, a noninvasive work-up for suspected pulmonary embolism is effective in hospitalized patients, allowing to forego angiography in 61% of them, and it appears to be safe, although this should be further investigated. In contrast to outpatients, D-dimer measurement appears to be useless in hospitalized patients.

The present study reports on a new calibration of the magnetic resonance imaging (MRI) signal intensity of a fast gradient-echo sequence used for in vivo myocardial perfusion quantification in patients. The signal from a FAST sequence preceded by a arrhythmia-insensitive magnetization preparation was calibrated in vitro using tubes filled with various gadolinium (Gd) solutions. Single short-axis views of the heart were obtained in patients (n = 10) with normal cardiac function. Myocardial and blood signal intensity were converted to concentration of Gd according to the in vitro calibration curve and fitted by a one-compartment model. K1 [first-order transfer constant from the blood to the myocardium for the gadolinium-diethylenetriamine-pentaacetic acid (Gd-DTPA)] and Vd (distribution volume of Gd-DTPA in myocardium) obtained from the fit of the MRI-derived perfusion curves were 0.72+/-0.22 (mL/min/g) and 15.3+/-5.22%. These results were in agreement with previous observations on animals and demonstrated that a reliable measurement of myocardial perfusion can be obtained by MRI in patients with an in vitro calibration procedure.

We designed a simple and integrated diagnostic algorithm for acute venous thromboembolism based on clinical probability assessment of deep-vein thrombosis (DVT) or pulmonary embolism (PE), plasma D-dimer measurement, lower-limb venous compression ultrasonography, and lung scan to reduce the need for phlebography and pulmonary angiography.918 consecutive patients presenting at the emergency ward of the Geneva University Hospital, Geneva, Switzerland, and Hôpital Saint-Luc, Montreal, Canada, with clinically suspected venous thromboembolism were entered into a sequential diagnostic protocol. Patients in whom venous thromboembolism was deemed absent were not given anticoagulants and were followed up for 3 months.A normal D-dimer concentration (500 microg/L by a rapid ELISA) ruled out venous thromboembolism in 286 (31%) members of the study cohort, whereas DVT by ultrasonography established the diagnosis in 157 (17%). Lung scan was diagnostic in 80 (9%) of the remaining patients. Venous thromboembolism was also deemed absent in patients with low to intermediate clinical probability of DVT and a normal venous ultrasonography (236 [26%] patients), and in patients with a low clinical probability of PE and a non-diagnostic result on lung scan (107 [12%] patients). Pulmonary angiography and phlebography were done in only 50 (5%) and 2 (1%) of the patients, respectively. Hence, a non-invasive diagnosis was possible in 866 (94%) members of the entire cohort. The 3-month thromboembolic risk in patients not given anticoagulants, based on the results of the diagnostic protocol, was 1.8% (95% CI 0.9-3.1).A diagnostic strategy combining clinical assessment, D-dimer, ultrasonography, and lung scan gave a non-invasive diagnosis in the vast majority of outpatients with suspected venous thromboembolism, and appeared to be safe.

We present a complication of L4-L5 disk surgery and its treatment by interventional radiology which has not previously been reported. An accessory inferior polar artery of a crossed-fused renal ectopia was injured and the bleeding was successfully managed by selective embolization.

Background. Injury to the ascending aorta is a rare lesion that may present in various forms. A thorough analysis of this lesion is lacking in the literature. This study was undertaken to delineate the prevalence and modes of presentation of injuries to the ascending aorta after blunt trauma and to suggest guidelines for management. Methods. A retrospective analysis of autopsies performed in our department of forensic medicine on blunt trauma victims from 1984 to 1993 and a literature review of autopsy series were undertaken to delineate the prevalence and relevant characteristics of this injury. A case report from our institution and a review of the literature were used to provide information regarding clinical presentations of this injury and treatment approaches. Results. Three modes of presentation were encountered. (1) Presentation at autopsy: The prevalence of injury to the ascending aorta after a traffic accident was 2% in our autopsy series. Among 13 patients with this injury 12 had other associated, potentially lethal lesions. A massive hemopericardium was present in two patients only. In autopsy series the incidence of injury to the ascending aorta in patients with an injury to the aorta ranged from 0% to 23%. (2) Clinical presentation: Twenty-one patients were treated surgically and reported in the literature. Fourteen presented with a pseudoaneurysm and seven with a chronic sinus of Valsalva fistula. One patient with a pseudoaneurysm presented with signs of cardiac tamponade and required immediate decompression; the others were hemodynamically stable. Seven patients had a cardiac lesion (valve tear in six and cardiac contusion in one), and three had an arch vessel lesion. Aorta repair was performed under cardiopulmonary bypass in every patient. (3) Incidental presentation: Seven patients with a traumatic tear of the aortic valve presented an incidental lesion of the ascending aorta. It was a subadventitial hematoma in three patients and an intimal and medial tear in four patients. Aortic tears were reinforced by direct suture. Conclusions. Injury to the ascending aorta after blunt trauma is rare but lethal mostly from associated injuries. Survivors may appear in stable condition and present mostly with pseudoaneurysms of the ascending aorta or sinus of Valsalva fistula. Associated lesions to the heart and arch vessels should be looked for. Repair of the ascending aorta injury is performed under cardiopulmonary bypass.

A 3-year-old boy being followed up for bilateral club foot underwent a routine thorax radiography that revealed aortic arch enlargement. Echocardiography showed sinus of Valsalva dilatation. Because of clinical features such as hypertelorism, bifid uvula, and prominent forehead, a genetic investigation was conducted that confirmed Loeys-Dietz syndrome (LDS) by identifying a heterozygous mutation in the gene encoding transforming growth factor-β receptor type 2 (TGFBR2). Whole-body magnetic resonance angiography was performed on a 1.5T machine. The magnetic resonance protocol included 3-dimensional contrast-enhanced angiographic sequences of the body and time-of-flight sequences of the brain. Whole-body magnetic resonance imaging demonstrated typical cardiovascular findings: Dilatation of the aorta at the level of sinus of Valsalva; tortuosity of the aortic arch, the 2 internal carotid arteries, the 2 vertebral arteries, and left subclavian artery; …

Hybrid PET/MRI imaging techniques are become more readily available, and its role in viability assessment appears promising.

The contributions of cine gradient-echo (GRE) magnetic resonance imaging were compared with those of spin-echo (SE) imaging for the evaluation of morphologic, functional, and flow alterations in 78 cases of congenital and acquired cardiac diseases. High temporal and spatial resolution cine GRE images (256 phase-encoding steps, 256 x 256 acquisition matrix interpolated to 512 x 512 for display, 16-64 frames per cycle) and SE images were acquired in each case. Cine GRE images provided a better diagnostic evaluation than SE images in several cases: (a) both masses and thrombi could be differentiated from flow artifacts; (b) abnormalities in cardiac function, such as infarction, abnormal wall motion, and ventricular dysfunction, could be evaluated; (c) small defects, shunts, and abnormal communications could be clearly seen; and (d) valvular regurgitations, poststenotic flow alterations, and aortic coarctation could be assessed. Cine GRE imaging was also valuable for postoperative evaluations. The authors believe that cine GRE imaging is a useful addition to SE sequences, especially for the assessment of blood flow and cardiac function.

Computed tomographic angiography (CTA) is a frequent noninvasive alternative to digital subtraction angiography. We previously reported the development of a new subtraction software to overcome limitations of adjacent bone and calcification in CT angiographic subtraction. Our aim was to further develop and improve this fast and automated computerized software, universally available for free use and compatible with most CT scanners, thus enabling better delineation of vascular structures, artifact reduction, and shorter reading times with potential clinical benefits. This computer-based free software will be available as an open source in the next release of OsiriX at the Web site http://www.osirix-viewer.com.

SummaryBecause the use of radioactive fibrinogen uptake test (FUT) has become questionable both for ethical (risk of virus transmission) and technical (lack of sensitivity) reasons, we investigated the potential value of two alternative methods for screening of asymptomatic deep venous thrombosis following elective digestive surgery: liquid crystal contact thermography (LCCT) and measurement of plasma concentration of D-dimer (DD), as compared with bilateral ascending phlebography. Out of 194 patients, 185 underwent phlebography on the 8th (0-19, median and range) postoperative day. Despite prophylaxis with low-molecular-weight heparin and elastic stockings, DVT was detected on phlebography in 58 legs of 45 patients. Sensitivity of LCCT with respect to the presence of DVT was 55% (n = 184 patients) or 28% (n = 368 legs) with a specificity of 67% and 82%, respectively. These poor performances were obtained despite a good interobserver agreement for the LCCT assessments (overall kappa coefficient of 0.66 between three experts). The most accurate cut-off of DD for discriminating patients with or without DVT was 3,000 pg/1, as determined by ROC curve analysis. Sensitivity of a DD level of more than 3,000 pg/1 for the presence of phlebographically documented DVT on the 8th postoperative day was 89% for a specificity of 48%.Thus, LCCT cannot be used for screening of postoperative, mainly asymptomatic DVT following general surgery. On the other hand, measurement of plasma DD may be useful for initial screening, a negative result (level less than 3,000 pg/1) allowing to exclude DVT (negative predictive value of 93%) and a positive result (positive predictive value of 35%) requiring confirmation by phlebography. This sequential approach might be useful in studies of the efficacy of antithrombotic regimens for prophylaxis of DVT in patients at risk.

[Figure][1] [![Graphic][3] ][3][![Graphic][4] ][4] A 28-year-old man presented with paroxysmal hypertension (161/114 mm Hg) and tachycardia (131 beats/min). Urinary noradrenaline was 4,892 nmol/24 h (normal

A 65-year-old man with a 1-year clinical history of recurrent flush and diarrhoea was admitted to our hospital for severe right-sided heart failure. Abdominal computed tomography scan showed carcinoid tumour originating from gut with hepatic metastases. Chemotherapy with octreotid and arterial chemo-embolization of the hepatic metastases was initiated. Transthoracic echocardiography revealed severe tricuspid and pulmonary valve regurgitation …

A mother and her two children with idiopathic ascending aortic dilatation are reported. This provides further evidence that genetic factors are involved in the etiology of aortic aneurysms and calls for screening first-degree family members, including children, of young adult patients diagnosed with this condition.

Submitral left ventricular aneurysm is a rare cardiac pathology. Etiology remains still mysterious, but it is believed to be due to a congenital defect of the fibrous layer of the atrioventricular junction. Surgical closure of aneurysm rim is the therapy of choice, despite the diversity of surgical approaches and techniques. We present a young patient operated with a transmitral approach in our clinic. Posterior mitral leaflet (PML) detachment and then extension valvuloplasty by using autologous pericardium was performed in order to save the native mitral valve. We believe that respecting the integrity of native valve is of crucial importance in this young population of patients.

Cardiovascular magnetic resonance has been shown to provide high data quality for myocardial perfusion assessment. However, to analyze the perfusion data, some signal processing and modeling is needed to correct for motion related artifacts and limited spatial resolution. This study describes a method based on system identification, allowing, after a first step of image registration, to integrate and correct the partial volume effect in the myocardium perfusion quantification. This method is then applied to patients with coronary artery disease or hypertrophic obstructive cardiomyopathy.

We report the case of a 31-year-old woman with mediastinal Castleman's disease of the hyaline vascular type. This large tumor was safely resected after arterial embolization. We describe the steps of this interventional procedure and discuss related necessary precautions.

Cor triatriatum sinister is a rare cardiac anomaly. It is characterized by the presence of a fibromuscular membrane in the left atrium, thus forming a proximal chamber receiving the pulmonary veins and a distal chamber communicating with the mitral valve and the left atrial appendage. This rare pathology tends to coexist with a persistent left superior vena cava, whereas the presence of an anomalous systemic venous return is unusual. In this article, we report successful treatment of a patient with cor triatriatum sinister who has an additional systemic venous return anomaly.

Purpose To compare the effects on heart rate (HR), on left ventricular (LV) or arterial pressures, and the general safety of a non-ionic low-osmolar contrast medium (CM) and a non-ionic iso-osmolar CM in patients undergoing cardiac angiography (CA) or peripheral intra-arterial digital subtraction angiography (IA-DSA). Materials and methods Two double-blind, randomized studies were conducted in 216 patients who underwent CA ( n =120) or peripheral IA-DSA ( n =96). Patients referred for CA received a low-osmolar monomeric CM (iomeprol-350, n =60) or an iso-osmolar dimeric CM (iodixanol-320; n =60). HR and LV peak systolic and end-diastolic pressures were determined before and after the first injection during left and right coronary arteriography and left ventriculography. Monitoring for all types of adverse event (AE) was performed for 24 h following the procedure. t -tests were performed to compare CM for effects on HR. Patients referred for IA-DSA received iomeprol-300 ( n =49) or iodixanol-320 ( n =47). HR and arterial blood pressure (BP) were evaluated before and after the first 4 injections. Monitoring for AE was performed for 4 h following the procedure. Repeated-measures ANOVA was used to compare mean HR changes across the first 4 injections, whereas changes after the first injection were compared using t -tests. Results No significant differences were noted between iomeprol and iodixanol in terms of mean changes in HR during left coronary arteriography ( p =0.8), right coronary arteriography ( p =0.9), and left ventriculography ( p =0.8). In patients undergoing IA-DSA, no differences between CM were noted for effects on mean HR after the first injection ( p =0.6) or across the first 4 injections ( p =0.2). No significant differences ( p >0.05) were noted in terms of effects on arterial BP in either study or on LV pressures in patients undergoing CA. Non-serious AE considered possibly CM-related (primarily headache and events affecting the cardiovascular and digestive systems) were reported more frequently by patients undergoing CA and more frequently after iodixanol (14/60 [23.3%] and 2/47 [4.3%]; CA and IA-DSA, respectively) than iomeprol (10/60 [16.7%] and 1/49 [2%], respectively). Conclusions Iomeprol and iodixanol are safe and have equally negligible effects on HR and LV pressures or arterial BP during and after selective intra-cardiac injection and peripheral IA-DSA. Clinical application Iomeprol and iodixanol are safe and equally well tolerated with regard to cardiac rhythm and clinical preference should be based on diagnostic image quality alone.

Aims: To compare MRI and MRA with Doppler-echocardiography (DE) in native and postoperative aortic coarctation, define the best MR protocol for its evaluation, compare MR with surgical findings in native coarctation. Materials and methods: 136 MR studies were performed in 121 patients divided in two groups: Group I, 55 preoperative; group II, 81 postoperative. In group I, all had DE and surgery was performed in 35 cases. In group II, DE was available for comparison in 71 cases. MR study comprised: spin-echo, cine, velocity-encoded cine (VEC) sequences and 3D contrast-enhanced MRA. Results: In group I, diagnosis of coarctation was made by DE in 33 cases and suspicion of coarctation and/or aortic arch hypoplasia in 18 cases. Aortic arch was not well demonstrated in 3 cases and DE missed one case. There was a close correlation between VEC MRI and Doppler gradient estimates across the coarctation, between MRI aortic arch diameters and surgery but a poor correlation in isthmic measurements. In group II, DE detected a normal isthmic region in 31 out of 35 cases. Postoperative anomalies (recoarctation, aortic arch hypoplasia, kinking, pseudoaneurysm) were not demonstrated with DE in 50% of cases. Conclusions: MRI is superior to DE for pre and post-treatment evaluation of aortic coarctation. An optimal MR protocol is proposed. Internal measurement of the narrowing does not correspond to the external aspect of the surgical narrowing

We report the case of a 35-year-old man who had a transient ischemic cerebral attack and then underwent a percutaneous closure of the patent foramen ovale (PFO) with a Cardiastar device. One year later, the patient developed a cardiac tamponade due to an important hemorrhagic pericardial effusion. Transoesophageal echocardiography showed that one of the struts had impinged on the aortic root in the region adjacent to the transverse pericardial sinus. Therefore, we speculated that the strut had passed through the aortic wall by slow erosion, leading to the pericardial effusion. Cardiac CT and subsequent surgery confirmed the perforation of the left atrial roof and the aortic root by two struts of the device. This is the first reported case of late cardiac tamponade and underscores the importance of long-term follow-up after PFO closure device implantation.

Aortic coarctation can now be repaired surgically with excellent results. Even though rare, injury to the spinal cord resulting in paraplegia remains a major concern. Preoperative evaluation showing the absence of collateral circulation is valuable in order to introduce protective actions. This report describes our experience using a temporary bypass from the ascending to the descending aorta bypass in children undergoing surgical correction of aortic coarctation in the setting of poorly developed collateral circulation.Between 1990 and 2002, we undertook direct surgical repair in 56 patients with isolated aortic coarctation, 20 as neonates, 11 as infants, and 25 during childhood. From 1998 onwards, we introduced preoperative evaluation of the collateral circulation with magnetic resonance imaging. From that time, we placed a temporary bypass from the ascending to the descending aorta, using a polytetrafluoroethylene tube of 4 to 8 mm diameter, whenever distal pressures were shown to be 25 mmHg or less after test clamping, or when magnetic resonance imaging revealed absence of collateral circulation.We found excellent correlations between the direct intra-operative measurements of distal pressure and the findings at magnetic resonance imaging. Following introduction of the temporary bypass, we observed no neurological complications, nor were there any complications related to bypass. Freedom from restenosis was 96%.Preoperative magnetic resonance imaging, therefore, can accurately visualize poor collateral circulation in children with aortic coarctation. The use of a temporary bypass can possibly eliminate the risk of neurological sequels following direct repair of coarctation in children with poorly developed collateral circulation. The temporary bypass is both easy to apply and safe.

A 5 year old boy was referred for evaluation of a heart murmur. Slight stenosis of the left pulmonary artery and an abnormal connection between the left pulmonary vein and the innominate vein was found on transthoracic echocardiography. MRI confirmed a dilated levoatriocardinal vein of 9 mm between the left superior pulmonary vein …

Global left ventricular function is a prognostic indicator and is used to evaluate therapeutical interventions in patients with heart failure. Regional left ventricular function can be determined with tagged MRI. Assessment of global left ventricular function using the tagging data may have additional clinical value without incurring extra scanning time, which is currently a limiting factor in cardiac imaging. Direct determination of end-diastolic volume is not possible with conventional tagged MRI. However, end-systolic volume can be directly measured because myocardium-blood contrast improves through a tagged image series. We investigated the potential of tagged MRI using frequency-domain analysis software to retrospectively track end-diastolic contour from end-systolic contour and subsequently calculate the ejection fraction. Tagged MRI was compared with the standard bright-blood cine MRI in healthy volunteers ( n=20) and patients with previous myocardial infarction ( n=8). Left ventricular ejection fraction derived from tagged MRI is linearly correlated to left ventricular ejection fraction obtained by standard cardiac cine MRI ( y=1.0 x+1.31, r0.98, p=0.014). In addition, the inter-observer and intra-observer coefficient of variation for left ventricular ejection fraction measurements was low (CV(intra)=0.4%, CV(inter)=1.3%). With tagged MRI, only end-systolic volume needs to be manually determined, and accurate estimation of left ventricular ejection fraction is obtained because end-diastolic and end-systolic volumes are determined using identical anatomical points. Our data indicate that tagged MRI can be used to quantitatively assess both regional and global left ventricular function. Therefore, tagged MRI may be a valuable clinical tool for determining the prognosis and evaluating the effect of therapeutical intervention using a single imaging session in patients with left ventricular dysfunction.