Andreas Schnitzer
Heidelberg University
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Featured researches published by Andreas Schnitzer.
The Breast | 2009
M. Ruch; Joachim Brade; C. Schoeber; Uta Kraus-Tiefenbacher; Andreas Schnitzer; Dorothee Engel; Frederik Wenz; Marc Sütterlin; Stefan O. Schoenberg; Klaus Wasser
The purpose of this study was to assess mammographic and sonographic findings in a long-term follow-up (>or=3 years) after breast-conserving surgery (BCS) and IORT, either applied as boost or exclusively. Follow-up-findings of 54 patients were retrospectively evaluated and compared to a control group of 48 patients, treated with BCS and whole-breast radiotherapy. After IORT patients had a higher incidence of fat necroses manifesting as oil cysts in the late follow-up mammograms (n = 31 vs n = 8); furthermore, oil cysts were larger in the IORT group (median 4.5 vs 1.4 cm(2)). In 25 IORT patients the oil cysts arose from partially organized hematomas/seromas, which in this group were generally more frequent (n = 38 vs n = 9) and larger (median 3.6 vs 1.8 cm(2)). After IORT a decreasing incidence of hematomas/seromas was reciprocal to an increasing incidence of oil cysts, and the size of both entities correlated with each other. Liquid lesions with polypoid inner wall thickening on ultrasound, attributed to organized hematomas/seromas or fat necroses, appear more frequently after IORT (n = 15 vs n = 1). In conclusion, IORT is associated with a high incidence of large oil cysts, which arise from likewise large partially organized wound cavities. On ultrasound pronounced partial organization with polypoid inner wall thickening is a frequent finding in those cavities.
European Journal of Radiology | 2012
Klaus Wasser; M. Ruch; Joachim Brade; C. Schoeber; Uta Kraus-Tiefenbacher; Andreas Schnitzer; Dorothee Engel; Frederik Wenz; Marc Sütterlin; Stefan O. Schoenberg; Karen Buesing
The purpose of the study was to assess whether postoperative changes in the tumour bed after intraoperative radiotherapy (IORT) with low-energy X-rays complicate the mammographic evaluation. 54 patients receiving breast-conserving surgery and IORT were compared to a control group of 48 patients with conventional breast-conserving treatment. All patients were included in routine follow-ups (≥3 years) with mammography accompanied by ultrasound. By retrospective consensus reading the mammographic changes in the tumour bed were classified as absent, low or distinct. Using the same grading it was classified whether mammographic evaluation was complicated due to postoperative changes. Focusing the yearly follow-ups within a period of four years, distinct changes were found significantly more often after IORT (52-62% vs. 7-30%). After IORT the evaluation was significantly more often distinctly complicated in each follow-up, except for year 1 (16-21% vs. 0-8%). In the IORT group the distribution of findings was nearly stable over time. In the control group it changed over time and a distinctly complicated evaluation was no longer seen in the follow-ups of years 3 and 4. Overall, further non-routine diagnostic procedures due to unclear findings in the tumour bed became necessary in 7% (IORT) vs. 8% (control group) of the patients (p=0.86). Evaluation of mammograms is complicated after IORT. In contrast to conventionally treated patients postoperative changes and difficulties of evaluation do not decrease over time. Overall, after IORT the diagnostic uncertainty does not seem to be increased in ultrasound supported mammographic follow-ups. The topic needs further evaluation with larger study samples.
Breast Journal | 2013
Dorothee Engel; Andreas Schnitzer; Joachim Brade; Elena Blank; Frederik Wenz; Marc Suetterlin; Stefan O. Schoenberg; Klaus Wasser
Intraoperative radiotherapy (IORT) with low‐energy x‐rays is increasingly used in breast‐conserving therapy (BCT). Previous non‐randomized studies have observed mammographic changes in the tumor bed to be more pronounced after IORT. The purpose of this study was to reassess the postoperative changes in a randomized single‐center subgroup of patients from a multicenter trial (TARGIT‐A). In this subgroup (n = 48) 27 patients received BCT with IORT, 21 patients had BCT with standard whole‐breast radiotherapy serving as controls. Overall 258 postoperative mammograms (median follow‐up 4.3 years, range 3–8) were retrospectively evaluated by two radiologists in consensus focusing on changes in the tumor bed. Fat necroses showed to be significantly more frequent (56% versus 24%) and larger (8.7 versus 1.6 sq cm, median) after IORT than those in controls. Scar calcifications were also significantly more frequent after IORT (63% versus 19%). The high incidence of large fat necroses in our study confirms previous study findings. However, the overall higher incidence of calcifications in the tumor bed after IORT represents a new finding, requiring further attention.
Clinical Imaging | 2012
Klaus Wasser; Andreas Schnitzer; Dorothee Engel; Julia Krammer; Frederik Wenz; Uta Kraus-Tiefenbacher; Marc Suetterlin; Stefan O. Schoenberg; G. Weisser
The aim was to investigate changes in the tumor bed on magnetic resonance mammography (MRM) after intraoperative radiotherapy (IORT) and whether they would limit the diagnostic value of posttherapeutic MRM. We retrospectively investigated 36 patients undergoing MRM after IORT (median interval 2.8 years, range 0.4-7.1). Wound cavities with fat necrosis were common after IORT (81%). They were associated with persisting contrast enhancement, i.e., enhancement was mostly seen irrespective of the posttherapeutic interval. It normally presented as rim enhancement and did not cause any diagnostic uncertainty if viewed together with other tissue characteristics. We do not expect a limited diagnostic value of MRM after IORT.
IEEE Transactions on Medical Imaging | 2009
Dmitry Maksimov; Jürgen Hesser; Carolin Brockmann; Susanne Jochum; Tiina Dietz; Andreas Schnitzer; Christoph Düber; Stefan O. Schoenberg; Steffen J. Diehl
Separating bone, calcification, and vessels in computer tomography angiography (CTA) allows for a detailed diagnosis of vessel stenosis. This paper presents a new, graph-based technique that solves this difficult problem with high accuracy. The approach requires one native data set and one that is contrast enhanced. On each data set, an attributed level-graph is derived and both graphs are matched by dynamic programming to differentiate between bone, on one hand side, and vessel/calcification on the other hand side. Lumen and calcified regions are then separated by a profile technique. Evaluation is based on data from vessels of pelvis and lower extremities of elderly patients. Due to substantial calcification and motion of patients between and during the acquisitions, the underlying approach is tested on a class of difficult cases. Analysis requires 3-5 min on a Pentium IV 3 GHz for a 700 MByte data set. Among 37 patients, our approach correctly identifies all three components in 80% of cases correctly compared to visual control. Critical inconsistencies with visual inspection were found in 6% of all cases; 70% of these inconsistencies are due to small vessels that have 1) a diameter near the resolution of the CT and 2) are passing next to bony structures. All other remaining deviations are found in an incorrect handling of the iliac artery since the slice thickness is near the diameter of this vessel and since the orientation is not in cranio-caudal direction. Increasing resolution is thus expected to solve many the aforementioned difficulties.
Radiologe | 2014
Scheurlen K; Andreas Schnitzer; Julia Krammer; Clemens G. Kaiser; Stefan O. Schönberg; Klaus Wasser
ZusammenfassungHintergrundDas Umfrageergebnis einer vorangegangenen Studie hat gezeigt, dass die Galaktographie in Deutschland heute selten eingesetzt wird und häufig neuere Verfahren angewendet werden. Die Evidenz der Galaktographie soll überprüft und der von Ultraschall (US) und MR-Mammographie (MRM) gegenübergestellt werden.Material und MethodenEs erfolgte eine Recherche in den Datenbanken PubMed und Cochrane unter Berücksichtigung englisch- und deutschsprachiger Studien. Der Evidenzgrad wurde gemäß des Oxford Centre for Evidence-based Medicine eingestuft.ErgebnisseEs konnten 19 Studien eingeschlossen werden, wovon 14 die Galaktographie, 10 den US und 5 die MRM beinhalten. Es handelt sich fast ausschließlich um retrospektive Studien mit einem Evidenzgrad von maximal „3b“. Die Zahlen zur diagnostischen Wertigkeit zeigen eine äußerst hohe Spannweite. Aufgrund sehr variabler Fallzahlen und Berücksichtigung verschiedener Pathologien sind die Studien nur eingeschränkt vergleichbar.ZusammenfassungGalaktographie, US und MRM weisen eine schwache Evidenz auf und für kein Verfahren lässt sich eine Überlegenheit ableiten. Die Galaktographie muss somit in der modernen multimodal ausgerichteten Diagnostik nicht mehr als obligater Standard angesehen werden. Empfehlungen zur Abklärung der pathologischen Sekretion müssen in gängige Leitlinien aufgenommen werden und diese Tatsachen berücksichtigen.AbstractBackgroundThe survey results of a previous study showed that galactography is now rarely used in Germany and newer methods are applied. The evidential value of galactography should be established and opposed to the evidential value of ultrasound (US) and magnetic resonance mammography (MRM).Materials and methodsA search was carried out in PubMed and Cochrane involving studies written in English or German. The level of evidence was measured according to the Oxford Centre for Evidence-based Medicine.ResultsA total of 19 studies were included, 14 with results on galactography, 10 on US and 5 on MRM. Almost all studies were retrospective with an evidence assigned to level 3b or lower. The results on the diagnostic values showed a very wide range. Because of very variable numbers of cases and consideration of various pathologies, the studies are only comparable to a limited extent.ConclusionGalactography, US and MRM all show a weak level of evidence and no superiority of a particular method can be derived. Therefore, galactography can no longer be considered as a mandatory standard in modern multimodal imaging of the breast. Recommendations for the diagnostic work-up of pathological nipple discharge have to be included in current guidelines and must consider these facts.BACKGROUND The survey results of a previous study showed that galactography is now rarely used in Germany and newer methods are applied. The evidential value of galactography should be established and opposed to the evidential value of ultrasound (US) and magnetic resonance mammography (MRM). MATERIALS AND METHODS A search was carried out in PubMed and Cochrane involving studies written in English or German. The level of evidence was measured according to the Oxford Centre for Evidence-based Medicine. RESULTS A total of 19 studies were included, 14 with results on galactography, 10 on US and 5 on MRM. Almost all studies were retrospective with an evidence assigned to level 3b or lower. The results on the diagnostic values showed a very wide range. Because of very variable numbers of cases and consideration of various pathologies, the studies are only comparable to a limited extent. CONCLUSION Galactography, US and MRM all show a weak level of evidence and no superiority of a particular method can be derived. Therefore, galactography can no longer be considered as a mandatory standard in modern multimodal imaging of the breast. Recommendations for the diagnostic work-up of pathological nipple discharge have to be included in current guidelines and must consider these facts.
Clinical Imaging | 2012
Julia Krammer; Dorothee Engel; Johanna C. Nissen; Andreas Schnitzer; Marc Suetterlin; Stefan O. Schoenberg; Klaus Wasser
The study was initiated to characterize and better understand the natural characteristics of axillary lymph nodes (LNs) apparent on dynamic breast magnetic resonance imaging (MRI). The most important finding in 71 subjects that included healthy women was that 41% showed strong enhanced axillary LNs. The dynamic curves of these LNs revealed an initial mean signal increase of 197% (±58%), all of them with a following plateau (34%) or washout (66%). Our study points out that the previous understanding of contrast enhancement in breast lesions should be taken with care when assessing axillary LNs. This has to be considered especially in preoperative breast MRI.
European Journal of Radiology | 2013
Julia Krammer; Klaus Wasser; Andreas Schnitzer; Thomas Henzler; Stefan O. Schoenberg; Clemens G. Kaiser
OBJECTIVE The aim of this study was to evaluate the capability of dynamic contrast enhanced MR-mammography (MRM) for the interpretation of axillary lymph nodes (LNs) in patients with breast cancer. MATERIAL AND METHODS 25 patients with breast cancer preoperatively underwent both FDG positron emission computed tomography (PET-CT) and dynamic contrast enhanced MRM. The maximum signal increase (SImax) and curve shape (types I-III) of contrast enhanced LNs ≥ 0.5 cm (short-axis) were analyzed in MRM and correlated to the maximum standard uptake value (SUVmax) of FDG PET-CT. 29 healthy women with MRM served as control group. Enhancement kinetics of all malignant LNs were compared to LN findings of the healthy control group. RESULTS Overall 33 contrast enhanced LNs on preoperative MRM had a corresponding FDG uptake on PET-CT. 30 of the PET positive LNs were classified as surely malignant (mean SUVmax 7.3 (± 5.4)). The mean SImax of these LNs was not significantly different to the control group (222% vs 197%), but malignant LNs had a significantly higher rate of type III curves with rapid washout (93% vs 66%, p = 0.008). CONCLUSION The maximum signal increase is not capable of differentiating malignant from benign axillary LNs. However, since malignant LNs showed a higher frequency of rapid washout curves (type III curves) on corresponding MRM future studies should concentrate on the analysis of this parameter. In clinical routine the curve shape still should be taken with care as there is a high overlap with benign LNs.
Radiologe | 2010
Klaus Wasser; Andreas Schnitzer; Joachim Brade; Stefan O. Schoenberg
In the last decade sentinel lymph node biopsy has become a well-established method for axillary lymph node staging in patients with breast cancer. Using preoperative imaging modalities it can be tested whether patients are suitable for sentinel node biopsy or if they should directly undergo an axillary dissection. The imaging modalities used must be mainly characterized by a high positive predictive value (PPV). For this question B-mode ultrasound is the best evaluated method and provides clear morphological signs for a high PPV (>90%) but the sensitivity barely exceeds 50%. It has not yet been proven whether other modalities such as duplex sonography, magnetic resonance imaging, computed tomography (CT) or scintigraphy might achieve a higher sensitivity while still maintaining a high PPV. There is only some evidence that positron emission tomography (PET) might achieve a higher sensitivity. This should be confirmed by further studies because PET or PET/CT will play an increasing role for an initial whole body staging in patients with breast cancer in the near future.
Radiologe | 2014
Scheurlen K; Andreas Schnitzer; Julia Krammer; Clemens G. Kaiser; Stefan O. Schönberg; Klaus Wasser
ZusammenfassungHintergrundDie Galaktographie wird seit Jahrzehnten zur Abklärung der pathologischen Sekretion eingesetzt. Zwischenzeitlich haben sich neuere Verfahren wie der hochauflösende Ultraschall (US) und die MR-Mammographie (MRM) in der multimodalen Mammadiagnostik etabliert. Eine Umfrage an Brustzentren soll klären, inwieweit die Galaktographie oder neuere Verfahren der multimodalen Mammadiagnostik angewandt werden.Material und MethodenEine anonyme Onlineumfrage wurde deutschlandweit an 342 radiologischen Einheiten zertifizierter Brustzentren durchgeführt.ErgebnisseEs nahmen 177 Einheiten (52 %) teil. Dreizehn Prozent bieten keine Galaktographie an, 33 % führen maximal 5 Galaktographien pro Jahr durch, 24 % 6–10, 18 % 11–20, 8 % 21–50 und 5 % 51–100. 53 % siedeln die Methode in der Stufendiagnostik nach dem US und vor der MRM an, 32 % würden auch die MRM vorziehen. Nur 4 % setzen die Galaktographie initial ein.SchlussfolgerungDie Galaktographie ist an den Brustzentren heute kein obligater Standard mehr, und neuere Methoden werden bevorzugt. Es sollte anhand der Literatur überprüft werden, welche Evidenz der Galaktographie im Vergleich zu den anderen Verfahren bei dieser Fragestellung zukommt. Dies wird Thema des zweiten Teils dieser Arbeit sein.AbstractPurposeGalactography has been used in cases of pathological discharge for decades. Meanwhile other methods, such as high-resolution ultrasound (US) and magnetic resonance mammography (MRM) have been established for modern multimodal breast imaging. A survey among certified German breast care centers aimed to investigate to what extent galactography is currently used and whether newer techniques in multimodal imaging are preferred.Materials and methodsAn anonymous online survey was carried out nationwide and open to 342 radiology units in certified German breast care centers.ResultsA total of 177 units (52 %) participated in the survey of which 13 % generally do not provide galactography, 33 % conduct a maximum of 5 galactographies per year, 24 % conduct 6–10, 18 % 11–20, 8 % 21–50 and 5 % 51–100. Of the participants 53 % give first priority to US and prefer galactography to MRM in stepwise diagnosis and 32 % prefer MRM to galactography. Only 4 % use galactography initially.ConclusionCurrently galactography is no longer a mandatory standard and newer methods are preferred. The evidential value of galactography in comparison to other techniques should be established on the basis of the literature. The second part of this paper will deal with this question.