Anna M. Sailer

Diagnosing Intracranial Aneurysms With MR Angiography: Systematic Review and Meta-Analysis

Background and Purpose— The aim of this study was to evaluate the sensitivity and specificity of MR angiography (MRA) in the diagnosis of ruptured and unruptured intracranial aneurysms. Methods— A systematic search was performed on 4 electronic databases on relevant articles that were published from January 1998 to October 2013. Inclusion criteria were met by 12 studies that compared MRA with digital subtraction angiography as reference standard. Two independent reviewers evaluated the methodological quality of the studies. Data from eligible studies were extracted and used to construct 2×2 contingency tables on a per-aneurysm level. Pooled estimates of sensitivity and specificity were calculated for all studies and subgroups of studies. Heterogeneity was tested, and risk for publication bias was assessed. Results— Included studies were of high methodological quality. Studies with larger sample size tended to have higher diagnostic performance. Most studies used time-of-flight MRA technique. Among the 960 patients assessed, 772 aneurysms were present. Heterogeneity with reference to sensitivity and specificity was moderate to high. Pooled sensitivity of MRA was 95% (95% confidence interval, 89%–98%), and pooled specificity was 89% (95% confidence interval, 80%–95%). False-negative and false-positive aneurysms detected on MRA were mainly located at the skull base and middle cerebral artery. Freehand 3-dimensional reconstructions performed by the radiologist significantly increased diagnostic performance. Studies performed on 3 Tesla showed a trend toward higher performance (P=0.054). Conclusions— Studies on diagnostic performance of MRA show high sensitivity with large variation in specificity in the detection of intracranial aneurysms.

Pros and Cons of 3D Image Fusion in Endovascular Aortic Repair: A Systematic Review and Meta-analysis:

Purpose: To systematically review and meta-analyze the added value of 3-dimensional (3D) image fusion technology in endovascular aortic repair for its potential to reduce contrast media volume, radiation dose, procedure time, and fluoroscopy time. Methods: Electronic databases were systematically searched for studies published between January 2010 and March 2016 that included a control group describing 3D fusion imaging in endovascular aortic procedures. Two independent reviewers assessed the methodological quality of the included studies and extracted data on iodinated contrast volume, radiation dose, procedure time, and fluoroscopy time. The contrast use for standard and complex endovascular aortic repairs (fenestrated, branched, and chimney) were pooled using a random-effects model; outcomes are reported as the mean difference with 95% confidence intervals (CIs). Results: Seven studies, 5 retrospective and 2 prospective, involving 921 patients were selected for analysis. The methodological quality of the studies was moderate (median 17, range 15–18). The use of fusion imaging led to an estimated mean reduction in iodinated contrast of 40.1 mL (95% CI 16.4 to 63.7, p=0.002) for standard procedures and a mean 70.7 mL (95% CI 44.8 to 96.6, p<0.001) for complex repairs. Secondary outcome measures were not pooled because of potential bias in nonrandomized data, but radiation doses, procedure times, and fluoroscopy times were lower, although not always significantly, in the fusion group in 6 of the 7 studies. Conclusion: Compared with the control group, 3D fusion imaging is associated with a significant reduction in the volume of contrast employed for standard and complex endovascular aortic procedures, which can be particularly important in patients with renal failure. Radiation doses, procedure times, and fluoroscopy times were reduced when 3D fusion was used.

Computed Tomography Imaging Features in Acute Uncomplicated Stanford Type-B Aortic Dissection Predict Late Adverse EventsCLINICAL PERSPECTIVE

Background— Medical treatment of initially uncomplicated acute Stanford type-B aortic dissection is associated with a high rate of late adverse events. Identification of individuals who potentially benefit from preventive endografting is highly desirable. Methods and Results— The association of computed tomography imaging features with late adverse events was retrospectively assessed in 83 patients with acute uncomplicated Stanford type-B aortic dissection, followed over a median of 850 (interquartile range 247–1824) days. Adverse events were defined as fatal or nonfatal aortic rupture, rapid aortic growth (>10 mm/y), aneurysm formation (≥6 cm), organ or limb ischemia, or new uncontrollable hypertension or pain. Five significant predictors were identified using multivariable Cox regression analysis: connective tissue disease (hazard ratio [HR] 2.94, 95% confidence interval [CI]: 1.29–6.72; P=0.01), circumferential extent of false lumen in angular degrees (HR 1.03 per degree, 95% CI: 1.01–1.04, P=0.003), maximum aortic diameter (HR 1.10 per mm, 95% CI: 1.02–1.18, P=0.015), false lumen outflow (HR 0.999 per mL/min, 95% CI: 0.998–1.000; P=0.055), and number of intercostal arteries (HR 0.89 per n, 95% CI: 0.80–0.98; P=0.024). A prediction model was constructed to calculate patient specific risk at 1, 2, and 5 years and to stratify patients into high-, intermediate-, and low-risk groups. The model was internally validated by bootstrapping and showed good discriminatory ability with an optimism-corrected C statistic of 70.1%. Conclusions— Computed tomography imaging-based morphological features combined into a prediction model may be able to identify patients at high risk for late adverse events after an initially uncomplicated type-B aortic dissection.

Individualized CT Angiography Protocols for the Evaluation of the Aorta: A Feasibility Study

PURPOSE Ionizing radiation and iodinated contrast media are potential drawbacks to repetitive follow-up CT angiography in current practice. The aim of the present study was to optimize radiation dose and contrast agent volume by using individualized CT angiography protocols. MATERIALS AND METHODS Eighty consecutive patients referred for CT angiography of the whole aorta were prospectively evaluated. Patients were divided into groups of patients with a body mass index (BMI) < 28 kg/m(2) (group 1; n = 50) and those with a BMI ≥ 28 kg/m(2) (group 2; n = 30). A control group consisted of 50 consecutive patients who were retrospectively evaluated. CT angiography parameters on a second-generation dual-source scanner were 128 × 0.6-mm collimation, pitch of 0.9, rotation time of 0.33 seconds, tube voltages of 80/100/120 kVp (group 1/group 2/control), reference tube current of 400 mA, and image reconstruction at 1-mm/0.8-mm slice thickness (kernels, B30f [control] and I30f/strength 3 [groups 1/2]). The control group received 120 mL of contrast agent (300 mgI/mL) at 4.8 mL/s; groups 1 and 2 received 44 mL and 53 mL at 3.3 mL/s and 4 mL/s, respectively. Effective dose was evaluated for each patient. Image quality was determined by qualitative image analysis at the levels of the thoracic, abdominal, and pelvic aorta as nondiagnostic, diagnostic, good, or excellent, and quantitative image analysis was performed, including attenuation values and contrast-to-noise ratio (CNR). RESULTS Mean effective radiation dose values for CT angiography of the aorta were 3.7 mSv ± 0.7 in group 1, 6.7 mSv ± 1.4 in group 2, and 8.7 mSv ± 1.9 in the control group (P < .001). Mean attenuation values and CNR levels were 334 HU ± 66 and 16 ± 8, respectively, in group 1, 277 HU ± 56 and 14 ± 5 in group 2, and 305 HU ± 77 and 11 ± 4 in the control group. CONCLUSIONS Iterative reconstruction algorithms resulted in 23%-57% less radiation in combination with 55%-63% less contrast agent volume compared with standard CT protocols.

Cost-effectiveness modelling in diagnostic imaging: a stepwise approach

AbstractDiagnostic imaging (DI) is the fastest growing sector in medical expenditures and takes a central role in medical decision-making. The increasing number of various and new imaging technologies induces a growing demand for cost-effectiveness analysis (CEA) in imaging technology assessment. In this article we provide a comprehensive framework of direct and indirect effects that should be considered for CEA in DI, suitable for all imaging modalities. We describe and explain the methodology of decision analytic modelling in six steps aiming to transfer theory of CEA to clinical research by demonstrating key principles of CEA in a practical approach. We thereby provide radiologists with an introduction to the tools necessary to perform and interpret CEA as part of their research and clinical practice.Key Points• DI influences medical decision making, affecting both costs and health outcome. • This article provides a comprehensive framework for CEA in DI. • A six-step methodology for conducting and interpreting cost-effectiveness modelling is proposed.

Long segment recanalization and dedicated central venous stenting in an ultimate attempt to restore vascular access central vein outflow

Purpose Maintaining vascular access in patients undergoing chronic hemodialysis is a challenging process, especially in patients enduring multiple central line placements and in whom peripheral options have been exhausted. Case We present a case of a 60-year-old male without options for peripheral vascular access due to multiple failed arteriovenous fistulas for hemodialysis. Furthermore, bilateral subclavian, brachiocephalic veins and iliac veins were occluded or significantly obstructed. After long segment central vein recanalization, an upper arm loop arteriovenous graft was implanted. The recanalized segment was stented with a 12-mm dedicated venous nitinol stent. Conclusion Chronic central vein obstructions demand stents with both high radial force and flexibility. We recommend dedicated venous stents to improve technical success and reduce stent-related complications like early re-occlusion due to fracturing, kinking or straightening.

Quantification of Respiratory Movement of the Aorta and Side Branches

Purpose: To assess and quantify the magnitude and direction of respiratory movement of the aorta and origins of its side branches. Methods: A quantitative 3-dimensional (3D) subtraction analysis of computed tomography (CT) scans during inspiration and expiration was performed to determine the respiratory geometric movements of the aorta and side branches in 60 patients. During breath-hold expiration and inspiration, 1-mm-thick CT slices of the aorta were acquired in unenhanced and contrast-enhanced scans. The datasets were compared using dedicated multiplanar reformation image subtraction software to determine the change in position of relevant anatomic sections, including the ascending thoracic aorta (AA), the origins of the brachiocephalic artery (BA) and left subclavian artery (LSA), the descending thoracic aorta (DTA) at the level of the tenth thoracic vertebra, as well as the origins of the celiac trunk, superior mesenteric artery, and the renal arteries. Results: Complex movement was visible during inspiration; the regions of interest in the thoracic aorta and side branches moved in the anterior, medial, and caudal directions compared with the expiration state. Mean 3D movement vectors (± standard deviation) were 8.9±3.6 mm (AA), 12.0±4.1 mm (BA), 11.1±3.9 mm (LSA), and 4.9±2.5 mm (DTA). Abdominal side branches moved in the caudal direction 1.3±1.1 mm. There was significantly less movement in the DTA compared to AA (p<0.001). The correlation coefficient between the extent of LSA movement and thoracic excursion was 0.78. Conclusion: The aorta and side branches undergo considerable respiratory movement. The results from this study provide an important contribution to understanding aortic dynamics.

18 F-FDG PET/MRI in the diagnosis of an infected aortic aneurysm

We report a case where an integrated whole body 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET)/magnetic resonance imaging (MRI) is performed in the diagnostic work-up of a saccular aortic aneurysm. The integrated whole body 18F-FDG PET/MRI study answered all relevant diagnostic questions, clearly marking an infected aortic aneurysm, depicting the extent of the infected area in relation to the aortic branch vessels, and indicating the aortic lesion as the primary site of infection. The patient was successfully treated by open type V TAAA repair and pericardial graft replacement. Aortic wall infection was proven in cultures of the surgical specimen.

Lower extremity computed tomography angiography can help predict technical success of endovascular revascularization in the superficial femoral and popliteal artery

Objective: Preprocedural computed tomography angiography (CTA) assists in evaluating vascular morphology and disease distribution and in treatment planning for patients with lower extremity peripheral artery disease (PAD). The aim of the study was to determine the predictive value of radiographic findings on CTA and technical success of endovascular revascularization of occlusions in the superficial femoral artery‐popliteal (SFA‐pop) region. Methods: Medical records and available imaging studies were reviewed for patients undergoing endovascular intervention for PAD between January 2013 and December 2015 at a single academic institution. Radiologists reviewed preoperative CTA scans of patients with occlusions in the SFA‐pop region. Radiographic criteria previously used to evaluate chronic occlusions in the coronary arteries were used. Technical success, defined as restoration of inline flow through the SFA‐pop region with <30% stenosis at the end of the procedure, and intraoperative details were evaluated. Results: From 2013 to 2015, there were 407 patients who underwent 540 endovascular procedures for PAD. Preprocedural CTA scans were performed in 217 patients (53.3%), and 84 occlusions in the SFA‐pop region were diagnosed. Ten occlusions were excluded as no endovascular attempt to cross the lesion was made because of extensive disease or concomitant iliac intervention. Of the remaining 74 occlusions in the SFA‐pop region, 59 were successfully treated (80%) and 15 were unsuccessfully crossed (20%). The indications for revascularization were claudication in 57% of patients and critical limb ischemia in the remaining patients. TransAtlantic Inter‐Society Consensus A, B, and C occlusions were treated with 87% success, whereas D occlusions were treated with 68% success (P = .047). There were nine occlusions with 100% vessel calcification that was associated with technical failure (P = .014). Longer lengths of occlusion were also associated with technical failure (P = .042). Multiple occlusions (P = .55), negative remodeling (P = .69), vessel runoff (P = .56), and percentage of vessel calcification (P = .059) were not associated with failure. On multivariable analysis, 100% calcification remained the only significant predictor of technical failure (odds ratio, 9.0; 95% confidence interval, 1.8‐45.8; P = .008). Conclusions: Analysis of preoperative CTA shows 100% calcification as the best predictor of technical failure of endovascular revascularization of occlusions in the SFA‐pop region. Further studies are needed to determine the cost‐effectiveness of obtaining preoperative CTA for lower extremity PAD.

Rekanalisation des benignen Venenverschlusses: Bildgebung, Behandlung und Resultate

Die Behandlung chronischer Becken- und unterer Hohlvenenverschlusse beschrankte sich lange Zeit auf die offene Bypass-Chirurgie. Mit der Einfuhrung neuer Bildgebungsverfahren, Rekanalisationstechniken und Stent-Designs stellt die endovaskulare Behandlung eine wertvolle Alternative zur Operation dar und hat sich inzwischen als primare Behandlungsstrategie etabliert. Erfahrungen aus dem Zentrum der Autoren und anderen Zentren zeigen die noch kritischen Punkte sowie den notwendigen Konsens in der endovaskularen venosen Behandlung. Dies betrifft zum einen den Einsatz reproduzierbarer Bildgebung zur Indikationsstellung und Behandlungsplanung, zum anderen den Bedarf an Studien zur Analyse von Offenheitsraten fur die Wahl des optimalen Stent-Designs und der zu verwendenden Stenting-Technik. Des Weiteren ist die Auswirkung von hybriden Verfahren mit Anlegen von vorubergehenden arteriovenosen Fisteln im Hinblick auf Stent-Offenheitsraten weiter unklar. Der vorliegende Artikel beschreibt die Bildgebung von chronisch-venosen Verschlussen, schildert deren Behandlung und liefert eine technische Bewertung von derzeit verfugbaren endovaskularen Methoden.