[Endovascular aortic repair: the hostile aneurysm neck : Morphologic definition, impact on long-term outcome, and treatment options]. / Endovaskuläre Versorgung: der komplizierte Aneurysmahals : Morphologische Definition, Auswirkungen auf das Langzeitergebnis und Therapieoptionen.

DEFINITION: A hostile neck is defined by various anatomical conditions that describe a morphology of the proximal aneurysmal neck of infrarenal aortic aneurysms that is unfavorable for endovascular treatment (endovascular aortic repair, EVAR): proximal landing zone length ≤ 15 mm, angulation of the aortic neck > 60°, conical aortic neck, diameter of the aortic neck > 32 mm, and circumferential calcification/thrombus. EFFECTS ON OUTCOME: These morphological parameters are not only associated with a higher perioperative technical failure rate (primary type 1 endoleak) but also with poorer long-term results (secondary type 1 endoleak) and thus a higher reintervention rate in standard EVAR, so that standard EVAR should be reserved for a few exceptions in these cases. TREATMENT OPTIONS: Due to the rapid development of endovascular techniques in the last decade, we now have a variety of endovascular options for aneurysms with hostile necks, for both elective treatment and emergency care, in addition to conventional open surgery, which is still the standard method in many cases and is currently undergoing a renaissance: fenestrated endovascular aortic repair (FEVAR) as the method of first choice in the elective setting, EVAR with chimneys (ChEVAR), endosuture aneurysm repair (ESAR). An important option is the conservative approach, which can be a reasonable choice if the patient's preference is taken into account and a careful risk-benefit assessment is performed.

The zone 2 concept and distal stent graft positioning in TH 2-3 are associated with high rates of secondary aortic interventions in frozen elephant trunk surgery.

OBJECTIVES: The goal of this study was to investigate the association between the localization of the distal anastomosis (zone 2/3), the stent graft length (100-160 mm), the position of the distal end of the hybrid prosthesis and the need for secondary aortic intervention (SAI) in acute and chronic thoracic aortic disease after the frozen elephant trunk procedure. METHODS: From 2009 through 2020, a total of 232 patients (137 men; mean age, 61.7 ± 13.8 years) were treated with the frozen elephant trunk procedure. The main indications were acute aortic dissection type A (n = 106, 46%), chronic aortic dissection type A (n = 52, 22%) and degenerative thoracic aortic aneurysm (n = 74, 32%). RESULTS: The rate of SAI was significantly higher when we performed a distal anastomosis in zone 2 rather than in zone 3, whereas the rate of SAI was less frequent if the distal positioning of the hybrid prosthesis was below TH 4-5. Combining the zone 2 concept and the short stent graft length (100 mm) was associated with a significantly higher rate of SAIs. Patients with a distal anastomosis in zone 2 were significantly less likely to have a recurrent laryngeal nerve injury (P < 0.001). However, no association between a specific arch zone of a distal anastomosis and the occurrence of spinal cord injury was observed. CONCLUSIONS: Rates of SAIs are highest in patients who were treated with a distal anastomosis in zone 2 and a short stent graft (100 mm) with the distal end of the hybrid prosthesis at vertebral level TH 2-3.

Noninvasive detection of coronary lesions using 16-detector multislice spiral computed tomography technology: initial clinical results.

OBJECTIVES: The aim of our study was to evaluate the feasibility of detecting coronary artery lesions using a new computed tomography (CT) scanner with 16 detectors and faster gantry rotation. BACKGROUND: Computed tomography angiography of the coronaries permits assessment of the coronaries; however, image quality is still impaired by motion artifacts and calcifications. METHODS: Sixty patients scheduled for conventional coronary angiography (CCA) were additionally studied by multislice spiral computed tomography (MSCT). Calcium scores and a contrast-enhanced visualization of the coronaries were performed and analyzed regarding evaluability, presence of coronary artery lesions, and correct clinical diagnosis. RESULTS: Calcium scoring was successful in all patients; 58 of 60 patients had a diagnostic contrast-enhanced scan. Mean calcium score was 506 +/- 743 Agatston score equivalent (ASE); 13 of 58 (22%) patients had an ASE >or=1,000, 46 of 58 (78%) patients <1,000. In 763 coronary segments, CCA detected a total of 75 lesions >or=50%. The MSCT correctly assessed 54 of these. Twenty-one lesions were missed or incorrectly underestimated. Sensitivity was 72%, specificity 97%. When restricting analysis to patients with an ASE <1,000, 40 significant lesions >or=50% were seen on CCA, and MSCT correctly detected 39 lesions (sensitivity 98%, specificity 98%). Regardless of any threshold, the correct clinical diagnosis could be obtained in 58 of 60 (97%) of all patients. CONCLUSIONS: In individuals with low-to-moderate amounts of coronary artery calcium, 16-detector CT coronary angiography has high sensitivity and specificity for the diagnosis of significant coronary artery stenosis.

Diagnostic accuracy of multidetector computed tomography coronary angiography in patients with angiographically proven coronary artery disease.

OBJECTIVES: The aim of the present study was to evaluate the diagnostic accuracy in detecting high-grade coronary stenoses in patients with known coronary artery disease (CAD) using multidetector computed tomography (MDCT). BACKGROUND: The MDCT systems with electrocardiographic (ECG)-gating permit visualization of the coronary arteries. However, severe calcifications and higher heart rates are known to degrade image quality and limit correct diagnosis. METHODS: Sixty-six patients with proven CAD as assessed by conventional coronary angiography (CCA) were studied by MDCT (mean time 24 months postangiography). Total calcium score and all coronary arteries, including distal segments and side branches, were assessed with respect to evaluability, presence of high-grade coronary artery stenoses (>70%), and correct diagnosis. Results were compared to CCA. RESULTS: A total of 105 lesions were detected by CCA. The MDCT correctly detected 39 lesions (sensitivity 37%, specificity 99%). The correct clinical diagnosis could be obtained in 24 patients (36%). Artifacts due to elevated heart rates or severe coronary artery calcification were the main cause of degraded image quality inhibiting correct diagnosis. In 21/66 patients (32%) all four major coronary vessel segments could be visualized. A threshold for maximum heart rate and a maximum calcification level were established (65 beats/min and an Agatston Score Equivalent of 335, respectively). A second analysis was made using these thresholds. Of all patients studied, 10/11 (91%) were correctly diagnosed when adhering to these thresholds. CONCLUSIONS: When using MDCT as a noninvasive diagnostic modality to assess advanced CAD, it appears to be mandatory to preselect patients in order to achieve reliable results.

Visualization of pulmonary vein stenosis after radio frequency ablation using multi-slice computed tomography: initial clinical experience in 33 patients.

PURPOSE: Radio frequency ablation (RFA) of the pulmonary veins (PV) is an established technique for treatment of atrial fibrillation (AF). However, stenoses within the treated areas are well known complications. Thus, a reliable non-invasive diagnosis of PV stenosis would be an important step forward in the care of these patients (pts). Aim of the present study was the diagnostic accuracy of new multi-slice detected computed tomography (MSCT) in visualization of PV and in detecting PV stenosis. MATERIAL AND METHODS: A total of 33 pts (17 male, 16 female, mean age 57+/-10.2 years [40-71]) were included. Retrospectively ECG-gated CT angiography (CTA) was performed within 1 day to a maximum of 380 days after RFA with a MSCT scanner. Interpretation of the scan was performed on conventional contrast enhanced axial slices and on 3D volume rendering images (maximum intensity projection: MIP, multi-planar reconstruction: MPR). Lesion severity was determined on a semi-quantitative scale (mild: <20%, intermediate: 20-50%, severe >50%) and compared to conventional angiography which had been performed at the beginning and at the end of RFA. RESULTS: MSCTA was applied without any complications, and all treated pulmonary veins (n=73) could be visualized. Diagnostic image quality was obtained in all examinations. A significant stenosis was detected by conventional angiography in 26/73 (36%) PV (2/73 (3%) severe, 14/73 (19%) intermediate, 10/73 (14%) mild). Using MSCTA, only 13 stenosis in 73 treated PV could be visualized (1/73 (1%) severe, 6/73 (8%) intermediate, 6/73 (8%) mild). CONCLUSIONS: Multi-slice-detector CT is able to visualize PV and to detect PV stenoses. However, stenosis severity seems to be underestimated and not all lesions could be accurately detected. Larger studies have to be performed to further assess the diagnostic accuracy and clinical reliability of this new non-invasive method and to focus on the incidence of PV stenosis following RFA especially in long-time follow up.

Whole-body low-dose multidetector row-CT in the diagnosis of multiple myeloma: an alternative to conventional radiography.

OBJECTIVE: The goal of this study was to establish the feasibility of a low-dose whole-body multidetector row-CT (MDCT) protocol in the diagnosis of multiple myeloma (MM), as an alternative to conventional X-ray imaging, which is currently still state-of-the-art in these patients, with emphasis on the comparison of image resolution on axial and multiplanar reformatted (MPR) scans and reduction of radiation dose. MATERIAL AND METHODS: 100 patients with known MM, or monoclonal gammopathy of unknown significance (MGUS) underwent unenhanced whole-body MDCT on a 16-slice scanner in a randomised fashion, using a 16 x 1.5 mm collimation and four different energy parameters (40, 50, 60 and 70 mAs). Three different reconstruction algorithms were used in every patient (B40f, B50f and B60f kernel). CT scans were reviewed independently by two radiologists, with regard to correct classification into one of the three known MM stages, and recognition of fracture risk. Thereafter, axial and MPR images were evaluated in consensus by both readers, with respect to image resolution. Diagnosis of osteolytic lesions was performed on the basis of axial and multiplanar reformatted images, whereas the assessment of spinal misalignment and fracture was done only on MPR images. The distribution of image resolution categories (very good, good, sufficient, insufficient for diagnosis) was evaluated depending on following parameters: current time product, patient's weight, bone density and reconstruction algorithm. The effective radiation dose was determined with the aid of an anthropomorphic Alderson Rando-Phantom, using a tube current time product of 40 mAs, and then extrapolating it on all current time products applied in this study on a commercially available software program WinDose (Institute of Medical Physics, Erlangen, Germany). RESULTS: In all 100 patients, image resolution was diagnostic, regardless of scanning parameters, enabling correct classification of multiple myeloma patients. Image quality of MPR images was either equal or inferior to correspondent axial images in the delineation of smaller lytic lesions, because of the use of non-isotropic voxel size. However, they proved accurate in diagnosing fracture and spine misalignment. A strong dependency of image resolution on bone density was observed, with reduced quality in patients with either diffuse skeleton infiltration or concurrent osteoporosis. Spatial resolution was also dependent on the reconstruction algorithm and energy level (mAs) used, as well as on patient's weight, but their influence was low within the given ranges. A middle-frequency reconstruction algorithm (B50f kernel) proved beneficial for all energy protocols. The interobserver agreement was excellent (kappa = 0.95) for classification of MM-patients. Effective radiation dose of MDCT calculated at a tube current time product of 40 mAs was 1.7-fold higher than the mean radiation dose of conventional X-ray (4.1 mSv versus 2.4 mSv). DISCUSSION: Our study shows that whole-body low-dose MDCT investigational protocols are appropriate for the diagnosis of lytic bone changes and for assessment of fracture risk in multiple myeloma patients, representing a serious alternative to current standards.

Spontaneous, self-limited, non-atherosclerotic dissection of the superior mesenteric artery.

A case of spontaneous, non-atherosclerotic dissection of the superior mesenteric artery is described. The patient presented with severe abdominal pain. An initial computed tomography scan did not disclose any pathology, namely the major mesenteric arteries were perfused. The patient's initial symptoms resolved during the first 48 h under conservative treatment. Sagittal reconstruction from a follow-up computed tomography scan disclosed a 7 cm long dissection of the proximal superior mesenteric artery with thrombosis of the false lumen and residual blood flow through the true lumen. There were no signs of transmural infarction of the bowel. Anticoagulation with heparin and later with phenprocoumon was initiated and the patient is well after 6 months. Together with several other cases reported recently, and in contrast to previous experience, this case adds evidence that conservative treatment of spontaneous, non-atherosclerotic dissection of the superior mesenteric artery may be an alternative to surgery if residual blood flow is maintained.

ECG-gated 16-MDCT of the coronary arteries: assessment of image quality and accuracy in detecting stenoses.

OBJECTIVE: The aim of this study was to investigate image quality and diagnostic accuracy in detecting coronary artery lesions using a 16-MDCT scanner. MATERIALS AND METHODS: Thirty-seven patients (28 men, nine women) underwent unenhanced helical CT and MDCT angiography of the coronary arteries. After patients received oral beta-blocker medication, CT scans were obtained during a single breath-hold with a 16-MDCT scanner using ECG-gating (0.75-mm collimation, 2.8-mm table feed/rotation, 0.42-sec rotation time). The image quality was assessed in terms of artifacts and segment visibility by two reviewers. Stenosis severity was compared with the results of conventional invasive coronary angiography. RESULTS: The data evaluation of the image quality was based on a total of 488 segments, of which 380 segments were considered to have diagnostic image quality. One hundred eight segments (22.1%) could not be sufficiently evaluated because of severe calcifications (35 segments) and motion artifacts (73 segments). The mean calcium score (Agatston score equivalent [ASE]) was 524.3 +/- 807.6. Twenty-eight (75.7%) of the 37 patients had an ASE of less than 1,000 (mean ASE, 90.8 +/- 152.3 [SD]), and nine (24.3%) patients had an ASE of 1,000 or greater (mean ASE, 1,761.0 +/- 637.6). For detecting lesions 50% or greater (without any exclusion criteria), the overall sensitivity, specificity, positive predictive value, and negative predictive value were 59%, 87%, 61%, and 87%, respectively. When limiting the number of patients to those with a calcium score of less than 1,000 ASE, the threshold-corrected sensitivity for lesions 50% or greater was 93%; specificity, 94%; positive predictive value, 68%; and negative predictive value, 99%. CONCLUSION: In patients with no or moderate coronary calcification, MDCT of coronary arteries using 16-MDCT technology allows the reliable detection of coronary artery stenoses with high diagnostic accuracy. Obtaining an initial unenhanced scan was found to be mandatory to avoid performing useless examinations in patients with severe calcifications.

MDCT: cardiology indications.

In the past 2 years mechanical multidetector-row CT (MDCT) systems with simultaneous acquisition of four slices and half-second scanner rotation have become widely available. Data acquisition with these scanners allows for considerably faster coverage of the heart volume compared with single-slice scanning. This increased scan speed can be used for retrospective gating together with 1-mm collimated slice widths and allows coverage of the entire cardiac volume in one breath hold. Initial results from studies in correlation with intracoronary ultrasound suggest that MDTC technology not only offers the possibility to visualize intracoronary stenoses non-invasively but also to differentiate plaque morphology. This is especially the case with the next generation of 16-row multidetector CT. An increased number of simultaneously acquired slices and sub-millimeter collimation for cardiac applications allows true isotropic scanning with high temporal resolution. Contrast-enhanced MDTC is a promising non-invasive technique for the detection, visualization, and characterization of stenotic artery disease. It could act as a gate keeper prior to cardiac catherization and finally replace conventional diagnostic modalities.