Helical CT angiography with maximum intensity projection in the assessment of aortic coarctation after surgery

Stenotic lesions of aorta: Imaging evaluation using multidetector computed tomography angiography

Aortic involvement can be secondary to various pathologic disease processes. These may result in stenotic or aneurysmal aortic lesions with a varied spectrum of imaging findings including intra-luminal, mural, and periaortic changes along with associated loco-regional or distal changes, depending on the etiology. Multidetector computer tomography with its recent advances has become the frontline imaging modality for the evaluation of aortic pathologies. Comprehensive evaluation of the aortic pathology with simultaneous evaluation of lungs, bones, and visceral organs is possible with a single multidetector computer tomography acquisition. It allows accurate primary diagnosis, identifies important anatomic landmarks and relationships, and identifies associated cardiovascular anomalies. Moreover, it serves as an adjunct in diagnosis of various complications, helps in treatment planning and detection of disease progression during follow-up.

ECG-gated multislice Computed Tomography angiography as a comprehensive non-invasive imaging tool in patient with aortic coarctation

We describe a case of a 52-year-old-woman with aortic coarctation demonstrated by means of 40-slice MSCT angiography. Based on the information extracted from MSCT it was possible to display the anatomical configuration of the disease, the thoraco-abdominal collateral pathways. The best therapeutic approach was established on the basis of MSCT findings. MSCT is a reliable and comprehensive tool for the assessment of adult patients with aortic coarctation. (www.actabiomedica.it)

Coarctation of the aorta: management, indications for intervention, and advances in care

OPINION STATEMENT

Coarctation of the aorta (CoAo) accounts for 9 % of congenital heart defects. Balloon angioplasty has been the conventional endovascular treatment of choice for both native and recurrent coarctation in adults. Recent advancement in stent technology with the development of the covered stents has enhanced the scope for percutaneous management of both native CoAo and post-surgical CoAo. Stent implantation provides better hemodynamic results with larger acute diameter gain and better long-term hemodynamic benefit. Stenting also decreases the incidence of aneurysm formation. The development of biodegradable stents may revolutionize the percutaneous management of coarctation, as the degradation of the stent scaffold within 6 months of implantation will further decrease the incidence of restenosis. In the future stenting may suffice and obviate the need for open repair. Until then, surgical repair of CoAo is the preferred method in both infants and complicated lesions, leaving stenting to adults with focal and uncomplicated disease.

Reference curves for the aortic area by age

RATIONALE AND OBJECTIVES

The aim of this study was to establish reference curves and formulas for aortic cross-sectional area in patients from infancy to young adulthood.

MATERIALS AND METHODS

Patients (aged 2 days to 18.1 years) who underwent electrocardiographically gated cardiac computed tomography between May 2004 and December 2011 were retrospectively examined. These patients were further divided into a group of normal controls (without aortic disease) and a group with coarctation of aorta. In the group of normal controls, the cross-sectional area of the aorta was measured at six locations: the sinotubular junction, distal ascending aorta, proximal arch, distal arch, aortic isthmus, and descending aorta (DAO). Interobserver and intraobserver variability, gender differences, the relationship between aortic cross-sectional areas and age, and the ratio to the DAO were also examined. The area ratio to the DAO was also examined in the group with coarctation of the aorta.

RESULTS

A total of 65 patients and 365 measurable aortic segments were included in the analysis (55 normal controls and 10 patients with coarctation of aorta). Interobserver and intraobserver variability was limited (aside from measurements of the sinotubular junction). There were no gender differences in age and the cross-sectional areas of the different aortic segments. In the group of normal controls, the cross-sectional area of each aortic segment was highly correlated with age (all >0.90, P < .001). The reference curves and formulas for aortic cross-sectional area by age were also determined for further clinical use. In the normal controls, the <95% confidence intervals of the ratios of aortic isthmus to DAO, distal arch to DAO, and proximal arch to DAO were approximately 0.6, 0.8, and 1.0, respectively. In addition, in the group with coarctation, all area ratios of aortic isthmus to DAO were <0.6, which was significantly different from the group of normal controls (P < .001). The area ratios of distal arch to DAO and proximal arch to DAO were also significantly different between two groups (P < .001 for both).

CONCLUSIONS

Measurement of aortic area was reproducible. The established reference curves and formulas and minimal area ratios were convenient for further clinical use.

Aortic aneurysms: delayed complications of coarctation of the aorta repair using Dacron patch aortoplasty

Coarctation of the aorta is a diaphragmlike ridge narrowing the lumen of the proximal descending aorta. Although surgical repair has proven to be a successful treatment of coarctation of the aorta, immediate and delayed postoperative complications are not rare. Of particular interest is the occurrence of aneurysms after Dacron patch aortoplasty--often decades after surgery. Delayed complication rates of up to 50% have been reported. We describe the clinical-radiologic presentations of 3 late complications of Dacron patch angioplasty: aortobronchopleural fistula, leaking pseudoaneurysm, and giant descending aortic aneurysm--all successfully treated with bypass grafts. Because of the high incidence of delayed complications, lifelong surveillance is necessary. The chest x-ray may be the first clue to a delayed complication. Knowledge of radiologic findings is helpful in the detection of complications-before they become symptomatic. Transesophageal echocardiography, computed tomography angiography, or magnetic resonance imaging with multiplanar reconstruction is diagnostic.

CT angiography in pediatric extremity trauma: preoperative evaluation prior to reconstructive surgery

Computed tomographic angiography (CTA) is a noninvasive modality for evaluating the vascular system and planning treatment strategies. The goal of this study was to validate the clinical utility of CTA in assessment of suspected pediatric extremity traumatic vascular injury, prior to emergent and delayed reconstructive surgery. A retrospective review was performed of all operative patients under 18 years of age who underwent multidetector-row CTA for evaluation of suspected extremity vascular injury. Parameters investigated included age, type of injury, referral source, temporal relationship between the injury and the CTA, CTA findings, operations performed, intraoperative findings, and clinical outcome. Between January 2002 and September 2005, 10 pediatric patients (6 males/4 females; mean age 8 years old, range 3-17) sustained either blunt (N = 8) or penetrating (N = 2) trauma and underwent CTA of the upper (N = 5) or lower extremities (N = 5). A total of 30% (3/10) of patients were referred from the emergency department acutely, 50% (5/10) were referred from the inpatient wards subacutely, and 20% (2/10) were referred from the outpatient clinics electively. Half (N = 5) underwent CTA to evaluate need for vascular repair, whereas half (N = 5) underwent CTA to evaluate local vasculature for flap reconstruction. Overall, 40% (4/10) of CTA findings were normal, whereas 60% (6/10) revealed traumatic vascular injuries. Pertinent nonvascular findings included soft tissue defects (60%, 6/10), fractures (40%, 4/10), and contracture deformities (20%, 2/10). In all cases, procedures were completed without complications, and intraoperative findings confirmed those from CTA. At a mean follow-up of 28 months, all injuries have healed without complications. CTA is a reliable noninvasive modality to evaluate pediatric patients with suspected traumatic extremity vascular injury and to plan treatment strategies for both vascular repair and extremity reconstruction.

Comparison of maximum intensity projection and digitally reconstructed radiographic projection for carotid artery stenosis measurement

Digital subtraction angiography is being supplanted by three-dimensional imaging techniques in many clinical applications, leading to extensive use of maximum intensity projection (MIP) images to depict volumetric vascular data. The MIP algorithm produces intensity profiles that are different than conventional angiograms, and can also increase the vessel-to-tissue contrast-to-noise ratio. We evaluated the effect of the MIP algorithm in a clinical application where quantitative vessel measurement is important: internal carotid artery stenosis grading. Three-dimensional computed rotational angiography (CRA) was performed on 26 consecutive symptomatic patients to verify an internal carotid artery stenosis originally found using duplex ultrasound. These volumes of data were visualized using two different postprocessing projection techniques: MIP and digitally reconstructed radiographic (DRR) projection. A DRR is a radiographic image simulating a conventional digitally subtracted angiogram, but it is derived computationally from the same CRA dataset as the MIP. By visualizing a single volume with two different projection techniques, the postprocessing effect of the MIP algorithm is isolated. Vessel measurements were made, according to the NASCET guidelines, and percentage stenosis grades were calculated. The paired t-test was used to determine if the measurement difference between the two techniques was statistically significant. The CRA technique provided an isotropic voxel spacing of 0.38 mm. The MIPs and DRRs had a mean signal-difference-to-noise-ratio of 30:1 and 26:1, respectively. Vessel measurements from MIPs were, on average, 0.17 mm larger than those from DRRs (P < 0.0001). The NASCET-type stenosis grades tended to be underestimated on average by 2.4% with the MIP algorithm, although this was not statistically significant (P=0.09). The mean interobserver variability (standard deviation) of both the MIP and DRR images was 0.35 mm. It was concluded that the MIP algorithm slightly increased the apparent dimensions of the arteries, when applied to these intra-arterial CRA images. This subpixel increase was smaller than both the voxel size and interobserver variability, and was therefore not clinically relevant.

Magnetic resonance blood flow measurements in the follow-up of pediatric patients with aortic coarctation – A re-evaluation

BACKGROUND

Previous studies have suggested the feasibility of a non-invasive quantification of vascular trans-stenotic pressure gradients (DeltaP) by phase-contrast MR imaging (PC-MRI). Our purpose was to assess the value of MRI estimated pressure gradients as a screening tool for assessing hemodynamically significant (re-)coarctation of the aorta (CoA) in pediatric patients.

METHODS

Forty-three patients (median age (range), 16 (5-25) years) with CoA (38 postoperative and 5 native) and clinically suspected hemodynamically significant stenosis underwent quantitative and semi-quantitative PC-MRI blood flow measurements and 3D MR-angiography, Doppler ultrasound (US) and conventional catheter angiography (CCA, n=20). Estimated DeltaP for each modality was correlated with percent stenosis.

RESULTS

The percent stenosis correlated only moderately with DeltaP(MRI) (r=0.55, p<0.001) and DeltaP(CCA) (r=0.48, p<0.001). Only moderate correlations were observed between DeltaP(MRI) vs. DeltaP(CCA) (r=0.54, p=0.02) and vs. DeltaP(US) (r=0.40, p=0.01). In contrast, semi-quantitative analysis of PC-MRI flow profiles predicted with good sensitivity (88%) and specificity (88%) who would be operated on. Thirteen patients met hemodynamic and percent stenosis criteria by CCA for surgical intervention.

CONCLUSION

Measured pressure gradients using PC-MRI should be used cautiously when assessing patients for recoarctation of the aorta. The analysis of blood flow profiles by PC-MRI might be a promising alternative in assessing the hemodynamic significance of CoA.

Interrupted aortic arch in a neonate: multidetector CT diagnosis

We report the usefulness of multidetector CT angiography (CTA) in the diagnosis of interrupted aorta of a neonate. CTA is useful for evaluating malformations of the aortic arch, particularly in cases that cannot undergo conventional angiography or in which detailed information cannot be provided by echocardiography.

Aortic stenosis: spectrum of diseases depicted at multisection CT

Aortic stenosis, or narrowing of the aortic lumen, has many causes. It may originate in coarctation or pseudocoarctation of the aorta, midaortic dysplastic syndrome, atherosclerosis, Takayasu arteritis, aortic dissection, or various intraaortic and periaortic diseases or as a result of aortic surgical repair. The impedance of blood flow through the stenotic segment may lead to the development of various collateral arterial pathways, according to the location of stenosis. Aortography is the standard technique for evaluating aortic stenosis; however, helical computed tomography (CT), particularly multisection CT, may provide additional information or in some cases may be used instead of arteriography. Multisection CT can depict the aorta and thoracoabdominal collateral pathways in less than 1 minute and provide high-quality arterial-phase imaging data suitable for multiple two-dimensional and three-dimensional reformations. To produce a useful differential diagnosis, the imaging specialist must be able to recognize the type of stenosis and the configuration of collateral circulatory pathways.

MR findings of collateral circulation are more accurate measures of hemodynamic significance than arm-leg blood pressure gradient after repair of coarctation of the aorta

PURPOSE

To determine the relationship between percent stenosis and three indicators of hemodynamic significance-arm-leg blood pressure gradient, direct visualization of collaterals, and percent increase flow from proximal to distal descending thoracic aorta-in patients with prior repair of coarctation of the aorta (CoA).

MATERIALS AND METHODS

Magnetic resonance imaging (MRI) examinations of 19 patients with prior repair of CoA were retrospectively reviewed. Percent stenosis was compared to the arm-leg blood pressure gradient as obtained from chart review, the depiction of collaterals by gadolinium-enhanced magnetic resonance angiography (MRA), and the percent increased flow in the distal thoracic aorta as measured by velocity-encoded cine MRI. Some imaging series or blood-pressure values were not available in some patients. All of the data were available for 15 of the 19 patients.

RESULTS

The arm-leg blood pressure gradient showed no statistical association with percent stenosis (R(2) = 0.10, P = 0.22), direct visualization of collaterals (P = 0.80), or percent increase in flow (R(2) < 0.01, P = 0.85). Percent stenosis did show association with visualization of collaterals (P = 0.01) and increase flow (R(2) = 0.62, P < 0.01).

CONCLUSION

The arm-leg blood pressure gradient is not a reliable indicator of hemodynamic significance of restenosis in patients with prior repair of CoA. Direct visualization of collateral vessels by MRA and percent increase in flow from proximal to distal descending thoracic aorta are reliable indicators of hemodynamic significance.

MR imaging and CT of vascular anomalies and connections in patients with congenital heart disease: significance in surgical planning

To plan effective management of congenital heart disease, one needs the clearest understanding of the anatomy. Although echocardiography and angiography are the dominant imaging modalities in patients with congenital heart disease, magnetic resonance (MR) imaging and computed tomography (CT) are valuable noninvasive adjuncts. MR imaging and CT are effective in demonstrating the complex cardiovascular morphology present in congenital heart disease, especially the extracardiac morphology. In patients with tetralogy of Fallot with complex pulmonary artery anatomy, MR imaging and CT are useful in demonstrating the pulmonary artery anatomy, along with the significant aortopulmonary collateral vessels. In the heterotaxy syndromes, patients often have unusual atriovenous connections. MR imaging allows accurate identification of the hepatic, systemic, and pulmonary veins and their relationships to both atria. CT and MR are the imaging modalities of choice in a patient who is thought to have a vascular ring. Treatment of aortic coarctation is usually performed on the basis of typical clinical and echocardiographic findings. In patients with atypical clinical or echocardiographic findings, MR imaging and CT yield helpful information that can change the treatment plan. The enhanced preoperative understanding of congenital heart disease provided by MR imaging and CT simplifies surgical decision making and consequently may improve outcome.

Surgery for aortic coarctation: a 30 years experience

OBJECTIVE

A retrospective study to review the experience of a single center with surgery for aortic coarctation over a period of 30 years (1970-1999).

METHODS

Criteria for inclusion: (a) aortic coarctation, isolated or associated with congenital heart defect; (b) surgery between 1970 and 1999. Data recorded: (1) date of surgery; (2) age at surgery; (3) associated lesions; (4) surgical technique; (5) simultaneous surgical procedures; (6) early and late surgical results in term of: (a) deaths; (b) need for reoperation because of re-coarctation or other cardiac lesion; (c) residual/recurrent pressure gradient, evaluated at cuff/Doppler at rest; (d) systemic hypertension, requiring medical treatment.

RESULTS

One hundred and forty-one patients underwent surgery for aortic coarctation: 30 neonates, 29 infants, 45 children and 37 adults. Associated lesions were found in 8/37 (=21.6%) adults and in 73/104 (=70.1%) pediatric patients. There were no hospital deaths. During the follow-up there were one late death in the adults group (1/37=2.7%) and three late deaths in the pediatric group (3/104=2.9%), all unrelated with aortic coarctation. Re-operation because of re-coarctation occurred only in ten late survivors of the pediatric group (10/101=9.9%), 9/10 operated on before 1980 (P<0.00001). End-to-end anastomosis, enlarged to the aortic arch in neonates, was associated with the lowest incidence of re-coarctation (P<0.005). A significant (>20 mmHg at rest) pressure gradient was found in none of the adults, and in seven of the 91 pediatric patients (7/91=7.7%) late survivors. Three adults (3/36=8.3%) late survivors are on medical treatment to control systemic hypertension.

CONCLUSIONS

The long-term results of our retrospective study confirm that surgery has to be considered the gold standard for the treatment of aortic coarctation. The interventional angioplasty techniques have to provide long-term outcome at least similar to the results obtained with surgery.

Feasibility of multi-slice computed tomography in the diagnosis of arteriogenic erectile dysfunction

OBJECTIVE

To compare computed tomography (CT) angiography (CTA) obtained by multi-slice CT (a new minimally invasive method) with the current standard of arterial imaging, digital subtraction angiography (DSA), in diagnosing arteriogenic erectile dysfunction (ED).

PATIENTS AND METHODS

Twenty-one patients with suspected arteriogenic ED underwent DSA and CTA after providing informed consent. Prostaglandin E1 was injected into the penile cavernosal body and then non-ionic contrast medium was rapidly infused into the antecubital vein. The DSA and CTA images were diagnosed as showing a normal or abnormal status by three reviewers independently. CTA was undertaken on an outpatient basis but DSA required hospitalization.

RESULTS

In the 42 internal pudendal arteries, DSA showed 28 normal and 14 impaired arteries; CTA showed 21 normal arteries and 21 occlusions. The CTA image correlated closely with the diagnosis of stenosis or occlusion in internal pudendal arteries, with a sensitivity of 93%, a specificity of 71% and an accuracy of 79%. In the cavernosal arteries, DSA depicted 14 normal and 28 impaired arteries; CTA showed seven normal arteries and 35 occlusions. The CTA image agreed closely with the diagnosis of stenosis or occlusion in cavernosal arteries, with a sensitivity of 96%, a specificity of 43% and an accuracy of 79%. Of the 42 inferior epigastric arteries, DSA could not depict 11 arteries but CTA showed all 42 inferior epigastric arteries.

CONCLUSIONS

CTA images correlated with DSA images; at present DSA is better than CTA in visualizing stenosis in fine arteries. However, CTA is less invasive and relatively inexpensive, and in future will probably provide even greater improvements in graphic quality. CTA would be an adequate replacement for DSA in evaluating internal pudendal arterial stenosis.