Intra-individual, randomised comparison of the MRI contrast agents gadobutrol versus gadoteridol in patients with primary and secondary brain tumours, evaluated in a blinded read.

OBJECTIVE: To prove that 1.0 M gadobutrol provides superior contrast enhancement and MRI image characteristics of primary and secondary brain tumours compared with 0.5 M gadoteridol, thereby providing superior diagnostic information. METHODS: Brain MRI was performed in two separate examinations in patients scheduled for neurosurgery. Independent injections of 1.0 M gadobutrol and 0.5 M gadoteridol at doses of 0.1 mmol Gd/kg body weight were administered per patient in randomised order. Evaluation was performed in an off-site blinded read. RESULTS: Fifty-one patients in the full analysis set (FAS) were eligible for efficacy analysis and 44 for the per-protocol analysis. For the primary efficacy variable "preference in contrast enhancement for one contrast agent or the other", the rate of "gadobutrol preferred" was estimated at 0.73 (95 % confidence interval 0.61; 0.83), showing significant superiority of gadobutrol over gadoteridol. Calculated lesion-to-brain contrast and the results of all qualitative secondary efficacy variables were also in favour of gadobutrol. Keeping a sufficient time delay after contrast application proved to be essential to get optimal image quality. CONCLUSION: Compared with 0.5 M gadoteridol, 1.0 M gadobutrol was proven to have significantly superior contrast enhancement characteristics in a routine MRI protocol of primary and secondary brain tumours.

[Interventional endovascular therapy of infrarenal abdominal aortic aneurysm]. / Die interventionelle/endovaskuläre Therapie des infrarenalen abdominellen Aortenaneurysmas.

The catheter-based interventional therapy (endovascular aortic repair EVAR) of abdominal aortic aneurysms (AAA) has gained an established place in the spectrum of therapeutic options. The procedure is characterized by low peri-interventional morbidity and mortality. Multislice computed tomography (CT) has a dominant role in defining the correct indications and in selecting an appropriate stent graft prior to the intervention. The rate of acute conversions could be reduced from 2.9 % to 0 % in our own elective patient population since 2010. In our vascular centre the proportion of patients treated by EVAR was 39.5 % (102 out of 258). The procedure is used routinely in patients who have an increased risk for general anesthesia or open surgery due to concomitant diseases. It is also used in patients with a reduced local operability due to prior surgery, abdominal diseases or radiation therapy. Arterial closure devices allow a completely percutaneous approach in a certain group of patients. However, after EVAR a life-long surveillance is mandatory because delayed therapy failure has been described. In younger patients who do not have a higher risk open surgery is still an option. The paper describes techniques, results und complications of EVAR.

[Quality report 2011 of the German Society of Interventional Radiology (DeGIR)--part 2. Endovascular treatment of aortic aneurysms (EVAR)]. / Qualitätsreport 2011: Bericht über die Behandlungsqualität minimalinvasiver Methoden--Teil 2. Interventionelle Therapie (EVAR) von Aortenaneurysmen.

PURPOSE: To analyze the quality of treatment for endovascular aortic aneurysm repair using the data of the DeGIR quality management system. MATERIALS AND METHODS: A retrospective analysis of all data registered in the DeGIR quality management system of the year 2011 was performed regarding the treatment quality for endovascular aortic aneurysm repair. Registry of data within this system was voluntary. Quality aims of correct indication, treatment strategy and results were examined. Special interest was directed towards treatment success, complication rates and radiation exposure. RESULTS: Out of 82,881 data sets from the year 2011 overall 1167 cases of EVAR were registered. 12.4% of these cases encompassed emergency treatments. The most frequent indication was an abdominal aneurysm with 85% of cases. The median aortic diameter was 56.5 mm. 253 cases showed an aortic diameter between 50 and 55 mm. Technical success was achieved in 94.6% of all cases including emergency indications for aortic rupture. The overall complication rate of all cases was 4% with 2.5% major complications. Examining only the elective cases a mortality rate of 0.34% was found. EVAR of ruptured aneurysms yielded a mortality rate of 12%. Median dose area product and fluoroscopy time were 10,676.5 cGy × cm2 und 17.32 min respectively. CONCLUSION: Data analysis of the DeGIR quality management system proved a very high technical success rate for the registered cases of endovascular aortic aneurysm repair accompanied by a low complication rate. Improvement of data quality will need further mandatory fields within the software to be implemented. KEY POINTS: The voluntary DeGIR quality management system has reached a high acceptance among radiologists. Endovascular aortic aneurysm repair by radiologists has shown a very high technical success rate and a very low complication rate.

[Optimised rate of specific, revascularising therapies in acute stroke--what is the aim? Considerations from the experience of a tertiary centre]. / Optimierte rate spezifischer revaskularisierender therapien beim akuten ischämischen schlaganfall--was ist das ziel? Erwägungen anhand der erfahrungen eines tertiären versorgungszentrums.

BACKGROUND: Recanalisation favourably influences outcome in acute stroke. Improved endovascular approaches seem to have higher recanalisation rates than systemic thrombolysis. Substantial efforts have been undertaken to increase the proportion of patients to whom these therapies can be applied. It is still unclear what rates can be realised in a clinical setting. PATIENTS AND METHODS: This is a retrospective single-centre analysis of patients with acute ischaemic stroke and specific recanalisation therapy primarily admitted to our tertiary care centre from 1/2010 to 3/2012. RESULTS: 20 % of patients received systemic thrombolysis, 20 % of these additional endovascular strategies. Pathological multimodal CT patterns were more common in patients not fulfilling the inclusion criteria for thrombolysis. Short-term clinical outcomes were similar in on-label and off-label applications. CONCLUSION: Structured clinical pathways including multimodal CT imaging are useful in identifying patients likely to profit from revascularisation therapies. Based upon our data, some realistic aims concerning therapy rates in patients with ischaemic stroke treated in everyday practice may be formulated (20/20 in 2020).

[Quality report 2011 of the Germyn Society of Interventional Radiology (DeGIR) - report about treatment quality of minimal invasive procedures]. / DeGIR-Qualitätsreport 2011 - Bericht über die Behandlungsqualität minimalinvasiver Methoden.

In 1994 the German Society of Interventional Radiology (DeGIR) introduced a voluntary quality mangement program. Out of a total of 82 881 of the year 2011, 36 467 patients, who received interventional recanalisation of pelvic or lower extremity arteries were chosen for an in depth analysis. In 33 104 (90.8 %) cases indication for interventional treatment was determined by at least one further discipline or even a multidisciplinary conference. Most treated patients were classified as Fontaine II or higher. Technical success rate over all procedures and regions was 96.2 % showing a very low failure rate of only 3.8 %. The overall complication rate was 3.2 %, periinterventional morbidity (complication C, D or E according to SIR classification) was 1.37 % and periinterventional mortality was 0.07 % (24 cases). X-ray exposure was recorded as well showing an average fluoroscopy time of 12 minutes and a dose-area product of 5034 cG × cm2. The voluntary quality management system was well accepted by the interventional radiologists. The software allows to compare the individual data of a single institution with the pooled data of all 192 participating radiology departments.

[Certification of vascular centers. Influence on quality and healthcare structures]. / Zertifizierung von Gefäßzentren. Auswirkungen auf Qualität und medizinische Versorgungsstrukturen.

Diagnosis and therapy of vascular diseases are increasingly being performed following a multimodal, interdisciplinary and less invasive approach. The introduction of specialized, organ-related centers is a logical consequence in view of a better treatment quality and a more effective use of resources. The German societies of radiology, vascular surgery and angiology jointly developed a process of certification, which has been successfully applied to more than 100 units in Germany. In this article the terms and results of the process are described and possible effects on the quality and structures of the healthcare system are discussed.

Ultrasound computed tomography in breast imaging: first clinical results of a custom-made scanner.

PURPOSE: To test a system using ultrasound computed tomography (USCT) that superimposes ultrasound data acquired in one cross-sectional plane from multiple angles around the breast (Full Angle Spatial Compounding, FASC) and to reconstruct the distribution of the speed of sound in the breast (SoS reconstruction). MATERIALS AND METHODS: We developed a system combining a conventional ultrasound scanner with a PC-controlled mechanical setup integrated in a custom-made examination couch. In a feasibility study, 3 volunteers (age 26 - 74 years) and one patient with breast cancer were studied. Subjects were placed in the prone position on this couch, with the breast hanging in a water tank. The ultrasound probe was moved in several planes around the breast. A curved reflector that followed the movement of the probe behind the breast was used to calculate the SoS within the breast tissue. Echo-data was processed offline by custom-made software to calculate both FASC and SoS images. RESULTS: In FASC images a reduction of artifacts (i. e. shadowing of Cooper's ligaments and irregular edges of inhomogeneous lesions) and speckles as well as clear visualization of the inner architecture of the breast was achieved. SoS images delivered further diagnostic information and helped to compensate for geometric distortions in the computed images. Difficulties in the visualization of lesions near the thoracic wall and/or the axillary are limitations of this technique. CONCLUSION: The first clinical results of USCT imaging have proven its feasibility as an automated and standardized technique for breast imaging.

Evaluation of clip artefacts in three-dimensional computed tomography.

OBJECTIVE: Recently, three-dimensional CT angiography (3D-CTA) has been used as a diagnostic method in postoperative evaluation after aneurysm clipping. A systematic analysis of possible predictors for good image quality needs to be conducted if 3D-CTA is to replace digital subtraction angiography in the postoperative setting. The aim of this study was to evaluate the influence of clip orientation on image quality and to assess titanium clip artefacts quantitatively on 3D-CTA. MATERIAL AND METHOD: Four different Yasargil titanium clips were placed on an acrylic glass tablet. Standardised 3D-CTA scanning was performed at clip-gantry angles of 0 degrees , 45 degrees and 90 degrees . Multiplanar reconstructions of the clips in frontal and lateral projections were performed. 3D-CTA image quality and the severity of titanium artefacts were judged by four observers. RESULTS: Twenty-four images were evaluated. Using frontal reconstructions, clip artefacts at a clip-gantry angle of 0 degrees were almost exclusively distributed along the long axis of the clip, with excellent evaluation quality at the lateral side of the clip branches. With decreasing clip-gantry angle (90 degrees and 45 degrees ) strong artefacts were localised laterally. On lateral reconstructions image quality was not significantly more restricted, regardless of the clip-gantry angles used. CONCLUSION: 3D-CTA image quality can be severely limited by clip artefacts. The expression and distribution of these artefacts depends on both the clip-gantry angle and the plane of image reconstruction. Overall, there is no correlation between clip-gantry angle and either the severity or the spatial distribution of clip artefacts leading to observable restrictions in the evaluation of surrounding structures.

Computed tomographic angiography in the evaluation of clip placement for intracranial aneurysm.

BACKGROUND: Computed tomographic angiography (CTA) has been shown to reliably detect aneurysms pre-operatively. The aim of this study was to compare the ability of post-operative CTA to detect aneurysmal remnants in connection with clip placement compared with digital subtraction angiography (DSA). Furthermore, special attention was paid to identifying factors influencing the image quality of CTA. METHOD: Between January 2005 and January 2006 a total of 76 patients with intracranial aneurysms were treated in our department. Thirty-two patients with a total of 33 clipped aneurysm were included in this study. All patients underwent CTA and DSA after surgery. Two investigators, each blinded to the classifications of the other, assessed image quality and clip placement. FINDINGS: In three patients aneurysmal remnants could be detected with CTA and DSA. One 2-mm aneurysmal remnant was not clearly identified on CTA; two small (<2-mm) aneurysmal remnants were definitely not seen on CTA. A single titanium clip was used for aneurysmal clipping in 26 patients, two clips were needed in six patients and one aneurysm required three clips being used. Overall, use of one titanium clip tended to result in better image quality. In addition, clip-gantry angles between 30 degrees and 60 degrees tended to yield better image quality. CONCLUSION: Post-operatively, CTA can be recommended as a reliable non-invasive diagnostic tool only with optimal image quality and with this criterion up to 66% of the aneurysms can be evaluated. Titanium artefacts, especially in the important zone (<2 mm) around the clip in which small aneurysmal remnants can occur, can render adequate evaluation impossible. CTA image quality depends on the number of titanium clips used, but clip-gantry-angle does not significantly influence the image quality.

[Selective embolization and surgical resection for head and neck glomus tumours--clinical outcome analysis]. / Präoperative Embolisation mit chirurgischer Resektion von Glomustumoren im Kopf-Hals-Bereich: Analyse der klinischen Ergebnisse.

The effectiveness and safety of angiographic embolization was investigated as a preliminary step prior to surgical excision of glomus tumours in the head and neck region. Embolization was performed in 54 patients presenting with a total of 58 chemodectomas, jugular (n=30), tympanicum (n=24) and caroticum (n=4) between the years 1988 and 2006. Embolization was considered successful if complete occlusion of all tumor-feeding vessels was achieved. The procedure was performed using polyvinylalcohol particles and microcoils and lasted for a median duration of 159 minutes. Complete tumor embolization was achieved in 72 % of patients. In 23%, it was partly successful and in 4% it was unsuccessful. 16% of patients experienced minor events during the procedure including hypotension, bradycardia, and vertigo. Following embolization, almost all patients (98%) had their tumour completely excised. Although the majority experienced minor postoperative complications (69%), one patient developed meningitis. There were no reported deaths. Angiographic embolization of glomus tumours in the head and neck before definitive excision can be safe and effective, resulting in an improved surgical outcome and tumour resectability.

3-Dimensional computed tomographic angiography for use of surgery planning in patients with intracranial aneurysms.

BACKGROUND: After subarachnoid haemorrhage (SAH) diagnostic evaluation of the underlying cause is warranted since the rebleeding rate is high. The objective of the study was to answer the question, whether 3-Dimensional computed tomographic angiography (3D-CTA) is able to accurately determine the surgical indications in patients with intracranial aneurysms. METHODS: After performing 3D-CTA the size of the aneurysm, direction of the aneurysmal dome, neck position and variants of the circle of Willis were analysed. Surgery was performed solely on CTA data in those cases, where the aneurysm was clearly visible. If the findings were negative or inconclusive, intra-arterial digital subtraction angiography (DSA) was also done. FINDINGS: Between January 2001 and December 2002 100 patients (68 F, 32 M) were examined and 123 aneurysms (86 ruptured and 37 unruptured) were diagnosed. All patients received CTA preoperatively and in 27 patients selective DSA was additionally performed. Postoperatively in 34 patients the operative result was checked by DSA. A good correlation between CTA and the intra-operative findings was present in 92 of 100 patients. One aneurysm was not seen on CTA, but was on DSA. In four cases we could confirm DSA findings in CTA after re-evaluation of the data. In three cases neither CTA nor DSA clearly showed an aneurysm, but it was confirmed during surgery. A good correlation between CTA and DSA was found in 60 of 61 patients (98%). The correlation between CTA and intra-operative findings was good as expected in 92 patients, in 5 patients an aneurysm was detected on re-evaluation. Only one aneurysm could not be demonstrated by CTA but in DSA. CONCLUSION: CTA is less invasive, less time consuming, cheaper and easier to demonstrate the essential information regarding the aneurysm than DSA. We therefore recommend that following a careful analysis most aneurysms - 92% - can be operated solely on CTA data.

[Contrast media kinetic in multi-slice helical CT cannot detect rectal cancer recurrence with certainty]. / Die Kontrastmittelkinetik im Mehrzeilen-Spiral-CT kann das Rektumkarzinomrezidiv nicht sicher detektieren.

PURPOSE: Evaluation of different parameters of contrast media enhancement for the differentiation between scar tissue and local recurrence of rectal cancer. MATERIALS AND METHODS: We included 83 patients after operation and radiotherapy of rectal cancer. In total, 20 local recurrences were diagnosed. After administration of 75 ml Iopromide (370 mg/ml) and a delay of 65 s, the whole abdomen and pelvis were scanned in a collimation of 4 x 2.5 mm and 12.5 mm table feed per rotation. The suspected tissue was marked by the freehand ROI option in every slice and the minimum, average and maximum densities were calculated. A local recurrence was suspected if maximum density was higher than 90 HU after admission of contrast media. In addition we calculated the maximum difference of density as the difference between maximum and minimum density. RESULTS: The minimum and average densities showed no reliable differences for patients with or without local recurrence (minimum density 4 HU ( +/- 12 HU) vs. 13 HU ( +/- 21 HU), P = 0.23, average density 48 HU ( +/- 10 HU), vs. 48 HU ( +/- 17 HU)), P = 0.52. The patients suffering from local recurrence showed higher maximum densities and a higher maximum difference than the patients without recurrence (maximum density 111 HU ( +/- 13 HU) vs. 81 HU ( +/- 24 HU), P = 0.02, maximum difference 103 HU ( +/- 20 HU) vs. 76 HU ( +/- 31 HU), P = 0.06. These differences were not significant. We calculated a sensitivity of 0.6, a specificity of 0.83, a positive predictive value of 0.52 and an accuracy of 0.77. CONCLUSION: It is not possible to diagnose a recurrent rectal cancer by density values alone.

Freehand ultrasound elastography of breast lesions: clinical results.

We developed a freehand method for ultrasound elastography, which can be applied during a routine sonographic examination with off-line calculation of strain images (elastograms). Forty-eight patients with 53 breast lesions were examined and, after biopsy or operation, histologic reports were available for all lesions. The correlation coefficient of time delay estimates was used as a quality criterion for the subsequent calculation of elastograms. Beyond the qualitative evaluation of elastograms, we suggested a semiquantitative approach. For that purpose, the elastogram of each lesion was normalized to an overall strain of 1% (i.e., the average strain in the image was set to 1%). After normalization, we determined mean strain values inside and outside of each lesion, respectively. Defining solid lesions as benign and malignant lesions except for fibrous mastopathy, we found significant difference in strain between solid lesions and their surrounding tissue. However, that result must not be misunderstood to suggest that it was possible to distinguish benign from malignant lesions in general. Still, we address the potential of ultrasound elastography to improve the detection and localization of breast lesions as well as their differential diagnosis. Besides, we developed a freehand applicator for further studies, which guarantees a homogeneous axial compression regardless of the experience of the examiner.

[Word generation in bilinguals--fMRI study with implications for language and memory processes]. / Wortgenerierung bei Bilingualen--eine fMRT-Studie mit Implikationen für Sprach- und Gedächtnisprozesse.

For over a century the cerebral representation of language functions is a matter of debate. In Neuroscience language is regarded as one of the most lateralized cognitive functions. Thus, while the language which is acquired first in most cases is processed by the left hemisphere some studies in brain damaged but also experimental investigations propose a pivotal role of the right hemisphere in second language processing. By the advent of modern neuroimaging it is now possible to study language lateralization and bilinguality also in healthy subjects. We studied first and second language abilities in a group of bilingual, healthy individuals by means of functional magnetic resonance imaging (fMRI) with a word-fluency paradigm. While we found a predominantly left prefrontal activity during both first and also second language processing an additional right prefrontal activation was registered during the use of second language. Our findings are discussed on the basis of an interaction between language and memory processes.