Tim F. Weber

Early and midterm results after endovascular stent graft repair of penetrating aortic ulcers

PURPOSE To present early and midterm results after endovascular stent graft repair of patients with penetrating aortic ulcers (PAU). METHODS Between January 1997 and March 2008, a total of 202 patients received thoracic aortic endografting in our institution, 48 patients (32 men, median age 70 years, range, 48-89) with PAU. A retrospective analysis of these patients was performed. Thirty-one patients (65%) showed an acute aortic syndrome (8 contained rupture, 23 symptomatic). Follow-up scheme included postoperative computed tomography angiography prior to discharge, at 3, 6, and 12 months, and yearly thereafter. Mean follow-up was 31.3 months (1.3-112.6). RESULTS Technical success was achieved in 93.7%. Primary clinical success rate was 81.2%. In-hospital mortality was 14.6%. Perioperative mortality was significantly (P = .036) higher in patients with acute aortic syndrome compared to asymptomatic patients (22.5% vs 0%). Postoperative complications occurred in 15 patients (31%), including 2 patients with minor strokes and 6, respectively, 5 patients with cardiac and/or respiratory complications. Early endoleaks were observed in 9 patients (19%), late endoleaks in another 2 patients. Reintervention was necessary in 4 out of 48 patients (8.4%). The actuarial survival estimates at 1, 3, and 5 years were 78% +/- 6%, 74% +/- 7%, and 61% +/- 10%, respectively. There was no aortic-related death during follow-up. Cox regression showed age (hazard ratio [HR]; 1.08, P = .036) and a maximum aortic diameter >50 mm (HR, 4.92; P = .021) as independent predictors of death. CONCLUSION Endovascular treatment of penetrating aortic ulcers is associated with a relevant morbidity and mortality rate in frequently highly comorbid patients. Midterm results could prove a sustained treatment success regarding actuarial survival and aortic-related death. Emergencies show a significantly worse outcome, but treatment is still warranted in these symptomatic patients.

Motion characterization of aortic wall and intimal flap by ECG-gated CT in patients with chronic B-dissection

RATIONALE AND OBJECTIVES To evaluate whether dynamic computed tomography (CT)-imaging can provide functional vessel information in patients with chronic aortic dissection type Stanford-B (ADB). MATERIALS AND METHODS In 32 patients, ECG-gated CT-angiography images were obtained. Cross-sectional area change and wall distensibility were investigated by semiautomatic vessel area segmentation at the end of aortic arch. Significance of distensibility differences was tested with regard to the aortic diameter, and the oscillation of the intimal flap was analyzed. RESULTS The aorta could be segmented successfully in all patients. These were separated into three subgroups: (A) 6 patients with an aortic diameter <4 cm and without a visible intimal flap, (B) 9 patients with an aortic diameter <4 cm, and (C) 17 individuals with an aortic diameter > or = 4 cm; (B) and (C) having a visible intimal flap. Differences in distensibility between the subgroups were not significant. Overall mean distensibility was D(tot)=(1.3+/-0.6) x 10(-5) Pa(-1). Analysis of intimal flap oscillation showed a pulsatile short axis diameter decrease of the true lumen of up to 29%. CONCLUSION Dynamic, ECG-gated CT-angiography can demonstrate pulsatile changes in aortic area and a highly variable motion of the intimal flap. Aortic distensibility appears independent of diameter or presence of a intimal flap. Follow-up studies may show correlation with possible complications.

Centerline Analysis of Aortic CT Angiographic Examinations: Benefits and Limitations

OBJECTIVE The purpose of our study was to illustrate workflow, benefits, and limitations of centerline analysis compared with double oblique multiplanar reformations using aortic CT angiography data. CONCLUSION Semiautomatic centerline analysis is beneficial for the assessment of aortic geometry and allows precise measurements of aortic diameters and lengths. It can be simple, fast, and reproducible, but it should be used with care considering its inherent limitations. Manually adjusted multiplanar reformations remain an essential tool for intuitive visualization of the vascular anatomy.

Expression of cytokeratin 20 in thyroid carcinomas and peripheral blood detected by reverse transcription polymerase chain reaction

We investigated a nested reverse transcriptase polymerase chain reaction (RT-PCR) system to detect CK20 mRNA in thyroid carcinomas, benign thyroid diseases and peripheral blood to improve diagnosis of thyroid carcinoma and to detect disseminated tumour cells. Frozen tissue samples of 46 thyroid carcinomas and 30 benign thyroid diseases (14 multinodular goiters, 14 follicular adenomas, two Hashimoto’s hyroiditis) were obtained intraoperatively. Preoperative blood samples were drawn from 31 patients with thyroid cancer, nine patients with benign thyroid disorders and 20 healthy volunteers. Nine out of nine medullary, 9/12 follicular, 7/19 papillary and 2/6 anaplastic carcinomas expressed CK20 transcripts. CK20 mRNA was undetectable in 30 tissue sections of benign thyroid diseases. Circulating tumour cells were found in the blood of 3/8 patients with medullary carcinoma, 2/8 patients with follicular carcinoma, 2/11 patients with papillary carcinoma and 1/4 patients with an anaplastic carcinoma. Nine blood samples of patients with benign thyroid diseases and 20 healthy volunteers tested negative. For the first time CK20 mRNA could be detected in tissue sections of thyroid carcinomas and peripheral blood samples of patients with thyroid cancer. It was not detectable in benign thyroid diseases. Our results therefore strongly suggest that CK20 RT-PCR assays may improve the diagnosis of thyroid carcinoma and is able to detect circulating tumour cells in peripheral blood of thyroid carcinoma patients.

Endovascular repair of ruptured thoracic aortic aneurysms is associated with high perioperative mortality and morbidity

PURPOSE To analyze early and midterm results after endovascular treatment of ruptured thoracic aortic aneurysms (rTAA). METHODS Between January 1997 and January 2009, a total of 236 patients received thoracic aortic repair in our institution; 23 patients (14 men; median age, 75 years; range, 60-88 years) due to a ruptured thoracic aortic aneurysm (rTAA). Rupture was defined according to computed tomography angiography (CTA) criteria with definite sign for hemorrhage outside the aortic wall. Patients with symptomatic TAA but with normal CT scans were excluded. A retrospective analysis of these patients was performed. Median follow up was 28 months (range, 0.1-82.5 months) and included serial aortic imaging at discharge, six, and 12 months and annually thereafter. RESULTS Technical success rate was 87%. The overall in hospital mortality was 48% with predominantly (50%) cardiac complications. Neurological complications occurred in three patients, two patients suffered from a transient ischemic attack (TIA)/stroke, and one patient experienced paraplegia after early conversion to open surgery. Primary endoleaks were seen in four of 25 patients (16%); no secondary endoleak was observed. Early conversion was necessary in two patients caused by an aortoesophageal fistula. The one- and three-year survival rates were 37.3% and 29.9% with no aortic or procedure-related death during follow up. Reintervention was necessary in four of 25 patients (16%). Cox regression analysis revealed preoperative renal insufficiency (hazard ratio [HR] 5.85, P = .0073) as an independent predictor of perioperative death. CONCLUSIONS The endovascular treatment of ruptured thoracic aortic aneurysms is associated with a high perioperative mortality and morbidity as well as poor midterm survival. Renal insufficiency proved to be an independent risk factor for perioperative death.

Type B aortic dissections: treating the many to benefit the few?

Purpose: It is now more than a decade since aortic stent-grafts were introduced clinically to provide a less invasive and potentially less harmful therapeutic option to treat type B aortic dissections. However, recent publications on best medical treatment and quality of life in patients with chronic type B dissection support conservative treatment due to the low incidence of aneurysm formation, rupture, and disease-related complications. Against this backdrop, we analyzed our experiences and now discuss whether the availability of endografts allowed us to change indications toward a more aggressive endovascular approach to acute and non-complex type B dissections, seeking to determine which patients we should treat and which ones we should observe. Methods: Between 1997 and 2008 in our institution in Heidelberg, we treated 172 patients with acute and chronic type B dissections, most (n=118, 69%) conservatively. However, 54 patients (40 men; mean age 57 years, range 30–82) underwent endovascular repair; 43% (n=23) were emergency cases. Patients were followed periodically with computed tomographic angiography. Results: Correct stent-graft deployment was achieved in 50 (93%) patients; the left subclavian artery was intentionally covered in 30 (55%) cases. Two carotid-subclavian bypass grafts were performed at the time of the endovascular repair due to partial coverage of the left common carotid artery. The perioperative complication rate was 19% (n=10), but there were no neurological sequelae. The 30-day mortality rate was 11% (n=6). Over a mean 32.1±25 months, 4 other patients died (18.5% overall mortality rate); survival estimates by Kaplan-Meier analysis were 80.4% and 66.1% after 1 and 5 years, respectively. Complete false lumen thrombosis was observed in 32 (60%) and a persisting completely patent false lumen in 3. The aortic expansion rate was 31% (17/54) overall. No difference was found between acute and chronic dissections in terms of survival (p=0.247). Conclusion: Despite a minimally invasive approach, complication and mortality rates for endovascular therapy of type B aortic dissections are considerable. Endografting is limited to symptomatic patients and those with chronic large aneurysmal expansion. At this stage in stent-graft development, asymptomatic patients benefit more from conservative treatment.

Accuracy and Variability of Semiautomatic Centerline Analysis versus Manual Aortic Measurement Techniques for TEVAR

OBJECTIVES This study aims to test whether inter-observer variability and time of diameter measurements for thoracic endovascular aortic repair (TEVAR) are improved by semiautomatic centerline analysis compared to manual assessment. METHODS Preoperative computed tomography (CT) angiographies of 30 patients with thoracic aortic disease (mean age 66.8 ± 11.6 years, 23 males) were retrospectively analysed by two blinded experts in vascular radiology. Maximum aortic diameters at three positions relevant to TEVAR were assessed (P1, distal to left common carotid artery; P2, distal to left subclavian artery; and P3, proximal to coeliac trunk) using three measurement techniques: manual axial slices (axial), manual double-oblique multiplanar reformations (MPRs) and semiautomatic centerline analysis. RESULTS Diameter measurements by both centerline analysis and the axial technique did not significantly differ from MPR (p = 0.17 and p = 0.37). Total deviation index for 0.9 was for P1 2.7 mm (axial), 3.7 mm (MPR), 1.8 mm (centerline); for P2 2.0 mm (axial), 3.6 mm (MPR), 1.8 mm (centerline); and for P3 3.0 mm (axial), 3.5 mm (MPR), 2.5 mm (centerline). Measurement time using centerline analysis was significantly shorter than for assessment by MPR. CONCLUSIONS Centerline analysis provides the least variable and fast diameter measurements in TEVAR patients with the same accuracy as the current reference standard MPR.

Reliability of Semiautomatic Centerline Analysis versus Manual Aortic Measurement Techniques for TEVAR among Non-experts

OBJECTIVES The study aimed to test whether reliability and inter-observer variability of preoperative measurements for thoracic endovascular aortic repair (TEVAR) among non-experts are improved by semiautomatic centerline analysis compared with manual assessment. METHODS Preoperative computed tomography (CT) angiographies of 30 patients with thoracic aortic disease (mean age 66.8 ± 11.6 years, 23 men) were retrospectively analysed in randomised order by one blinded vascular expert (reference standard) and three blinded non-expert readers. Aortic diameters were measured at four positions relevant to TEVAR using three measurement techniques (manual axial slices, manual multiplanar reformations (MPRs) and semiautomatic centerline analysis). Length measurements were performed using centerline analysis. Reliability was calculated as absolute measurement deviation (AMD) from reference standard and inter-observer variability as coefficient of variance (CV) among non-expert readers. RESULTS For axial, MPR and centerline techniques, mean AMD was 7.3 ± 7.7%, 6.7 ± 4.5% and 4.7 ± 4.8% and mean CV was 5.2 ± 4.2%, 5.8 ± 4.8% and 3.9 ± 5.4%. Both AMD and CV were significantly lower for centerline analysis compared with axial technique (p = 0.001/0.042) and MPR (p = 0.009/0.003). AMD and CV for length measurements by centerline analysis were 3.2 ± 2.8% and 2.6 ± 2.4%, respectively. Centerline analysis was significantly faster than MPR (p < 0.001). CONCLUSIONS Semiautomatic centerline analysis provides the most reliable and least variable diameter and length measurements among non-experts in candidates for TEVAR.

Aktuelle Bildnachverarbeitung der aortalen CTA und MRA

ZusammenfassungDie multiplanare Reformatierung (MPR) der Bilddaten aortaler CTA und MRA ist die wichtigste Rekonstruktionsmethode im Hinblick auf eine differenzierte Therapieentscheidung und die präoperative Therapieplanung sowie die Beschreibung postoperativer Komplikationen. Die gekrümmte MPR wird semiautomatisch bzw. vollständig automatisch als Centerline im Gefäßlumen berechnet und für die Bestimmung des orthogonalen Durchmessers und der Längsausdehnung der Pathologie verwendet. Eine reproduzierbar exakte Ausmessung komplexer Pathologien und Gefäßlängsverläufe erweitert das Spektrum der diagnostischen Radiologie. Die gekrümmte MPR dient der semiautomatischen Berechnung der Gefäßmittellinie. Die heutigen Gerätekonsolen können bereits automatisch Maximum-Intensitätsprojektionen (MIP) und Standard-MPR anfertigen und ins Archiv versenden. Die 3D-Visualisierung kann als Volume-rendering-Technik (VRT) effektiv bei der Patientenselektion, Therapieplanung und Nachsorge behilflich sein und in der interdisziplinären Kommunikation des klinischen Alltags ergänzend zu den Quelldaten eingesetzt werden. Die Segmentierung von Hochkontraststrukturen ist meist semiautomatisch möglich, Weichteilstrukturen müssen jedoch weiterhin manuell segmentiert werden. Zur Bildnachverarbeitung sind isotrope CTA-Daten meist besser geeignet als MR-Datensätze, die häufig noch anisotrop sind. In vielen europäischen Ländern wird die Bildnachverarbeitung noch nicht adäquat vergütet, obwohl die Überweiser die 3D-Visualisierungen und Vermessungen oftmals mit Nachdruck einfordern.AbstractMultiplanar reformation (MPR) is the most relevant tool for patient selection and precise procedural planning and also for analyzing postinterventional complications. Curved MPR is used primarily for semiautomated or completely automated calculation of the centerline of the vascular lumen and to estimate the orthogonal vessel diameter and longitudinal extent. Reproducible and accurate measurement of complex pathologies and courses of vessels extends the range of diagnostic radiology. Contemporary scanner consoles allow automated processing of maximum intensity projections (MIP) and standard MPR and their storage in PACS. To improve patient selection, procedural planning, root-cause analysis postoperatively for assessment of treatment effects and to make better communication of findings to nonradiologists possible, volume rendering techniques (VRT) are a beneficial adjunct to source images. With current algorithms semiautomated segmentation is satisfactory for vessels and bones, but not for low-contrast structures (soft tissues), which still need to be segmented manually. In general, isotropic CT source data are preferable to MR images, which are often anisotropic. In many European countries image postprocessing is still not adequately reimbursed although the doctors making referrals often specifically and emphatically demand 3D visualization and measurements in daily practice.Multiplanar reformation (MPR) is the most relevant tool for patient selection and precise procedural planning and also for analyzing postinterventional complications. Curved MPR is used primarily for semiautomated or completely automated calculation of the centerline of the vascular lumen and to estimate the orthogonal vessel diameter and longitudinal extent. Reproducible and accurate measurement of complex pathologies and courses of vessels extends the range of diagnostic radiology. Contemporary scanner consoles allow automated processing of maximum intensity projections (MIP) and standard MPR and their storage in PACS. To improve patient selection, procedural planning, root-cause analysis postoperatively for assessment of treatment effects and to make better communication of findings to nonradiologists possible, volume rendering techniques (VRT) are a beneficial adjunct to source images. With current algorithms semiautomated segmentation is satisfactory for vessels and bones, but not for low-contrast structures (soft tissues), which still need to be segmented manually. In general, isotropic CT source data are preferable to MR images, which are often anisotropic. In many European countries image postprocessing is still not adequately reimbursed although the doctors making referrals often specifically and emphatically demand 3D visualization and measurements in daily practice.

Heartbeat-related distension and displacement of the thoracic aorta in healthy volunteers.

PURPOSE To test our hypothesis that distension and displacement in various segments of the healthy thoracic aorta are significant and can be predicted based on clinical characteristics. MATERIALS AND METHODS Sixty-one Caucasian volunteers without cardiovascular disease (49 ± 16 years, range 19-82; 28 men, 33 women) divided into two age groups (A: <50, B: ≥ 50 years) underwent 1.5-T MRI. ECG-gated dynamic data sets were acquired at five locations perpendicular to the thoracic aorta. Aortic distension and Centre of Mass (CoM) displacement were determined as percentages of diastolic aortic diameter. A multiple linear regression model including age group, gender, location, mean arterial blood pressure, heart rate and body mass index was tested. RESULTS Mean aortic distension averaged over all locations was 11.2 ± 4.1% (age group A) and 6.7 ± 3.3% (age group B), mean displacement 15.1 ± 8.3% (A) and 11.0 ± 6.2% (B). Systolic and diastolic aortic diameter and CoM position significantly differed at all locations (p<0.001). Distension and displacement could be predicted based on the regression model (p<0.001). Age group A and women exhibited significantly greater distension and displacement compared to age group B (p<0.001) and men (p<0.01), respectively. Distension increased, displacement decreased from proximal to distal. CONCLUSION Distension and translational displacement are significant at all levels of the thoracic aorta and can be predicted based on clinical characteristics.