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E Wenkel

Publications and source records attributed to E Wenkel.

18 recordsLinked to original sources
PubMed2006

Experimental phantom lesion detectability study using a digital breast tomosynthesis prototype system.

PURPOSE: To compare the sensitivity of conventional two-dimensional (2D) projection imaging with tomosynthesis with respect to the detectability of mammographic phantom lesions. MATERIALS AND METHODS: Using a breast tomosynthesis prototype based on a commercial FFDM system (Siemens MAMMOMAT Novation), but modified for a wide angle tube motion and equipped with a fast read-out amorphous selenium detector, we acquired standard 2D images and tomosynthesis series of projection views. We used the Wisconsin mammographic random phantom, model RMI 152A. The anode filter combinations Mo/Mo and W/Rh at two different doses were used as typical radiographic techniques. Slice images through the phantom parallel to the detector were reconstructed with a distance of 1 mm employing a filtered back-projection algorithm. The image data sets were read by five radiologists and evaluated with respect to the detectability of the phantom details. RESULTS: For all studied radiographic techniques, the detection rate in the tomosynthesis mode was 100 %, i. e. 75 true positive findings out of 75 possible hits. In contrast, the conventional projection mode yielded a detection rate between 80 and 93 % (corresponding to 60 and 70 detected details) depending on the dose and X-ray spectrum. CONCLUSION: Tomosynthesis has the potential to increase the sensitivity of digital mammography. Overlapping structures from out-of-plane tissue can be removed in the tomosynthesis reconstruction process, thereby enhancing the diagnostic accuracy.

Algorithms↗
PubMed2005

[Digital mammography with high-resolution storage plates (CR) versus full-field digital mammography (CCD) (DR) for microcalcifications and focal lesions -- a retrospective clinical histologic analysis (n = 102)].

PURPOSE: To determine the diagnostic accuracy of microcalcifications and focal lesions in a retrospective clinical-histological study using high-resolution digital phosphor storage plates (hard copy) and full-field digital mammography (hard copy). MATERIALS AND METHODS: From May 2003 to September 2003, 102 patients underwent digital storage plate mammography (CR), using a mammography unit (Mammomat 3000 N, Siemens) in combination with a high resolution (9 lp/mm) digital storage phosphor plate system (pixel size 50 microm) (Fuji/Siemens). After diagnosis and preoperative wire localization, full-field digital mammography (CCD) (DR) was performed with the same exposure parameters. The full-field digital mammography used a CCD-detector (SenoScan) (Fisher Imaging) with a resolution of 10 Ip/mm and a pixel size of 50 microm. Five investigators determined the diagnosis (BI-RADS I - V) retrospectively after the operation from randomly distributed mediolateral views (hard copy reading). These results were correlated with the final histology. RESULTS: The diagnostic accuracy of digital storage plate mammography (CR) and full-field digital mammography (CCD) (DR) was 73 % and 71 % for all findings (n = 102), 73 % and 71 % for microcalcifications (n = 51), and 72 % and 70 % for focal lesions (n = 51). The overall results showed no difference. CONCLUSION: Our findings indicate the equivalence of high-resolution digital phosphor storage plate mammography (CR) and full-field digital mammography (CCD) (DR).

Adult↗
PubMed2005

[Interventional methods in diagnostics of the breast -- a new vacuum biopsy system for the breast in routine clinical practice].

AIM: To evaluate the diagnostic potential of the new vacuum-assisted method VacuFlash (VF) in clinical routine of breast diagnostics. METHOD: From april 2002 to march 2003, the new sonographically guided vacuum-assisted system VacuFlash was used in 75 patients with a BI-RADS 5 lesion (analogue). The patients were aged between 31-75 yrs (median: 51 yrs), the size of the lesions measured 8-33 mm (median: 14 mm). 5 specimens were taken from each lesion. RESULTS: In 69 of the 75 lesions (92 %, respectively), malignancy was confirmed. In 8 lesions (8 %, resp.), we found a benign histology, confirmed by consecutive surgery. CONCLUSION: The new vacuum-assisted device VacuFlash is a technically perfected and applicable diagnostic method. Especially in the view of the cost it has to be compared with high-speed core cut biopsy, the hand-held Mammotome system and open surgical biopsy. High-speed core cut biopsy seems to be the standard procedure in diagnostic percutaneous breast intervention to clarify sonographically detected breast lesions.

Adult↗
PubMed2004

[3D ultrasound in core breast biopsy].

AIM: To evaluate the potential of three-dimensional ultrasound (3D US) in core biopsy of suspicious breast lesions. METHOD: 3D US controlled core biopsy was performed in 107 breast masses in 100 women by using an automated biopsy system (11G coaxial needle, 12 G biopsy needle). Mean diameter of the lesions was 1.55 cm (0.5 - 3.5 cm). A linear 3D US volume scanner was used for the procedure. Localization of the lesion and placement of the needle were initially done under 2D US guidance. After core needle stroke a 3D US volume acquisition was performed to correlate lesion and needle position. In the case of eccentric needle position the needle was repositioned under 3D control. 5 specimens were taken from each lesion. The histological results from the specimens were correlated with the results from surgery or clinical follow-up (> 2.5 years). RESULTS: Biopsy was taken from 59 probably benign (BI-RADS 3 - 4) and 48 malignant (BI-RADS 5) lesions. 3D US revealed 61 central, 44 eccentric and 2 marginal needle positions after the initial 2D guidance. Central repositioning of the needle was achievable under 3D guidance in all patients. Histological examination of the specimens revealed 41 invasive carcinomas and one in-situ carcinoma (DCIS). In one lesion, the carcinoma was missed in the core biopsy, despite central hits of the biopsy needle. This led to a sensitivity of 98 %, specificity of 100 %, PPV of 100 %, NPV of 98.5 % and accuracy of 99 % for the diagnosis of a malignant lesion. CONCLUSION: 3D US improves needle positioning as well as the depiction of correct needle placement in freehand core biopsy.

Adult↗
PubMed2004

[Phantom study for the detection of simulated lesions in five different digital and one conventional mammography system].

PURPOSE: Experimental phantom study for the detection of simulated lesions with five different digital and one conventional screen-film mammography system. MATERIALS AND METHODS: Three radiographs were obtained at various configurations of the phantom with one conventional screen-film system (Mammomat 3000 N) (Siemens), five digital systems (high resolution computed radiography system [Fuji/Siemens], one a-Si detector [GE Medical Systems], two a-Se detectors [Siemens; Hologic / Lorad] and one CCD detector [Fischer Imaging]), applying the same exposure parameters. The Wisconsin Mammographic Random Phantom, Model 152 A, was used. Five investigators with different experience in mammography (3 months to more than 4 years) evaluated the 18 randomly selected radiographs. RESULTS: No significant differences were found in the detection rate of simulated breast lesions for conventional screen-film mammography (84.9 %), high resolution computed radiography (86.7 %) and digital mammography with an a-Si detector (89.8 %). Highly significantly better results (p < 0.001) were found with the two a-Se systems (97.3 %) and the CCD system (100 %). CONCLUSION: Conventional screen-film mammography can be replaced by high resolution computed radiography and digital mammography with a-Si-, a-Se- and CCD-detectors. This has to be confirmed in further clinical studies.

Computer Simulation↗
PubMed2003

Experimental investigations of image quality in X-ray mammography with a conventional screen film system (SFS) and a new full-field digital mammography unit (DR) with a-Se-detector.

PURPOSE: Determination of image quality of a new digital mammography system with an a-Se-detector. MATERIAL AND METHOD: Radiograms of the Wisconsin Mammographic Random Phantom, Modell 152 A (Radiation Measurements Inc., Wisconsin) were acquired using a conventional film screen and a digital system. RESULTS: With the conventional film screen system there were detected 191/a 38.2 and with the digital mammography 219/a 43.8 of 225 possible details. CONCLUSION: Based on these results there is the possibility to replace the conventional film screen system by the digital mammography with a-Se-detector--this has to be confirmed in further clinical trials.

Breast Neoplasms↗
PubMed2003

[Film-screen mammography versus digital storage plate mammography: hard copy and monitor display of microcalcifications and focal findings--a retrospective clinical and histologic analysis].

PURPOSE: A retrospective clinical-histological study to determine the diagnostic accuracy of mammography using conventional screen-film cassettes (hard copy), high-resolution digital phosphor storage plates (hard copy) and monitor display (soft copy) for microcalcifications and focal lesions (BI-RADS (TM) category 4 or 5). MATERIALS AND METHODS: From April to November 2001, 76 patients underwent conventional film-screen mammography and, after diagnosis and preoperative wire localization, digital mammography with the same exposure parameters. Five investigators retrospectively determined the diagnosis after the operation from randomly distributed mediolateral views (hard-copy reading) and from the monitor display (soft-copy reading). These results were correlated with the final histology. RESULTS: The accuracy of conventional screen-film mammography, digital mammography and monitor-displayed mammography was 67%, 65% and 68% for all findings, (n = 76), 59%, 59% and 68% for microcalcifications (n = 44) and 75%, 72% and 63% for focal lesions (n = 32). The overall results showed no difference. CONCLUSION: Our findings indicate equivalence of conventional screen-film mammography, high-resolution digital phosphor storage plate mammography and monitor-displayed mammography.

Adenocarcinoma↗
PubMed2003

[Experimental investigations at the new digital mammographic system].

PURPOSE: Experimental investigations of a new digital mammography system. MATERIALS AND METHODS: The digital mammography system SenoScan (Fischer Imaging) is based on 4 charged coupled devices (CCD) (slot detector). The pixel size is 50 micro m, field of view 21 x 29 cm (2), effective quantum efficiency (DQE) (0) 50 %, spatial resolution 10 lp/mm, and memory depth 12 bit. The object of investigation was the Wisconsin Mammographic Random Phantom, Model 152 A (Radiation Measurements Inc., Wisconsin). The radiograms were acquired using the digital mammography system. RESULTS: The digital mammography detected 225 of 225 possible details. The surface dose was 6.95 mGy. CONCLUSIONS: These experimental results support the use of the digital mammography in practice. This has to be confirmed in further clinical trials.

Female↗
PubMed2002

[Do tissue marker clips after sonographically or stereotactically guided breast biopsy improve follow-up of small breast lesions and localisation of breast cancer after chemotherapy?].

PURPOSE: We wanted to determine if tissue marker clips after sonographically or stereotactically guided breast biopsy improve the follow-up of small breast lesions classified BI-RADS 4/5 and the localisation of breast cancer (TNM stage 2 or 3) after neoadjuvant chemotherapy. MATERIAL AND METHODS: Prospective analysis was performed of 108 breast lesions 1 cm or smaller mammographically classified as BI-RADS 4/5 and 14 breast lesions larger than 2 cm mammographically classified as BI-RADS 5. 33 of the 108 breast lesions 1 cm or smaller underwent sonographic core cut breast biopsy (group 1) and 75 stereotactic vacuum-assisted breast biopsy (group 2). All 14 lesions greater than 2 cm were stereotactically vacuum-assisted breast biopsied (group 3). The centre of the lesion was marked by a clip after the biopsy. Mammographies were performed in all patients of group 1 and 2 with a histologically benign finding (n = 31, n = 69, respectively) and in all patients of group 3 directly after clip placement and after 6 and 12 months. Clip localisation and possible divergence from the original position were verified by a grid. RESULTS: Two patients of group 1 and 6 patients of group 2 had breast conservative surgery (BET) because of the histological diagnosis of a ductal carcinoma in situ or invasive breast cancer. The tissue marker clips of the remaining 31 patients of group 1 and 69 patients of group 2 diverged with a mean value of 0.4 cm (standard deviation +/- 0.23 cm; range 0.1 cm to 0.9 cm) from their placement position after 6 months. After 12 months the marker clips deviated with a mean value of 0.4 cm (standard deviation +/- 0.21 cm; range 0.1 cm to 0.9 cm) in 94 patients and 0.8 cm (standard deviation +/- 0.25 cm; range 0.1 cm to 0.9 cm) in 6 patients from their original location. No tumour progression of the benign lesions in group 1 and 2 was diagnosed in follow-up mammograms. In all patients of group 3 the tissue marker clips were the only possibility to localize the tumour after neoadjuvant chemotherapy as all other diagnostic methods showed inconsistent results. CONCLUSION: Positioning a tissue marker clip in the tumour centre seems to be reasonable after interventional biopsy of breast lesions of 1.0 cm or smaller and before neoadjuvant chemotherapy.

Antineoplastic Agents↗
PubMed2002

[Influence of heart rate on image quality and detection of coronary stenoses with multislice spiral CT].

Multi-slice spiral CT (MSCT) permits the detection of coronary stenoses. We investigated the influence of the patient's heart rate (HR) during the scan on stenosis detection and the presence of motion artifacts. In 100 patients MSCT was performed and retrospectively ECG-gated cross-sectional images were reconstructed. 115 of 400 coronary arteries (29%) were unevaluable due to motion artifacts (84/115) or other reasons (31/115). In evaluable arteries, sensitivity was 91% (51/56 high grade stenoses detected), specificity was 89%. With increasing HR, the number of unevaluable arteries increased and overall sensitivity for stenosis detection decreased from 62% (HR < or = 70 bpm) to 33% (HR > 70 bpm). MSCT permits detection of coronary stenoses, but evaluability and accuracy decrease with increasing HR.

Aged↗
PubMed2001

Detection of coronary artery stenoses by contrast-enhanced, retrospectively electrocardiographically-gated, multislice spiral computed tomography.

BACKGROUND: Multislice spiral computed tomography (MSCT) with retrospectively ECG-gated image reconstruction permits coronary artery visualization. We investigated the method's ability to identify high-grade coronary artery stenoses and occlusions. METHODS AND RESULTS: A total of 64 consecutive patients were studied by MSCT (4x1 mm cross-sections, 500-ms rotation, table feed 1.5 mm/rotation, intravenous contrast agent, retrospectively ECG-gated image reconstruction). All coronary arteries and side branches with a luminal diameter >/=2.0 mm were assessed concerning evaluability and the presence of high-grade stenoses (>70% diameter stenosis) or occlusions. Results were compared with quantitative coronary angiography. Of 256 coronary arteries (left main, left anterior descending, left circumflex and right coronary artery, including their respective side branches), 174 could be evaluated (68%). In 19 patients (30%), all arteries were evaluable. Artifacts caused by coronary motion were the most frequent reason for unevaluable arteries. Overall, 32 of 58 high-grade stenoses and occlusions were detected by MSCT (58%). In evaluable arteries, 32 of 35 lesions were detected, and the absence of stenosis was correctly identified in 117 of 139 arteries (sensitivity, 91%; specificity, 84%). If analysis was extended to all stenoses with >50% diameter reduction, sensitivity was 85% (40 of 47) and specificity was 76% (96 of 127). CONCLUSIONS: MSCT with retrospective ECG gating permits the detection of coronary artery stenoses with high accuracy if image quality is sufficient, but its clinical use may presently be limited due to degraded image quality in a substantial number of cases, mainly due to rapid coronary motion.

Aged↗
PubMed2001

Experimental investigations of image quality in X-ray mammography with conventional screen film system (SFS), digital phosphor storage plate in/without magnification technique (CR) and digital CCD-technique (CCD).

Comparison of image quality in X-ray mammography between conventional film screen film system (SFS), digital phosphor storage plate in and without magnification technique (CR) and digital CCD-technique (CCD). Radiograms of an RMI-mammography phantom were acquired using a conventional screen film system, three digital storage plate systems and two digital systems in CCD-technique. Additionally, the radiograms of one digital phosphor storage plate system were post-processed regarding contrast and included in the comparison. The detectability of details was best with the digital mammography in CCD-technique. After confirming these promising results in clinical studies, digital mammography should be able to replace conventional screen film technique.

Breast Neoplasms↗
PubMed2000

Benign meningioma: partially resected, biopsied, and recurrent intracranial tumors treated with combined proton and photon radiotherapy.

PURPOSE/OBJECTIVE: To evaluate the recurrence-free survival and complications of combined proton and photon radiotherapy of patients with incompletely resected or recurrent histologically-confirmed benign meningioma. METHODS AND MATERIALS: Between May 1981 and November 1996, 46 patients with partially resected, biopsied, or recurrent meningiomas (median age of 50 years; range 11-74 years) were treated with combined photon and 160-MeV proton beam therapy at the Massachusetts General Hospital (MGH) and the Harvard Cyclotron Laboratory, using computed tomography-based conformal 3D treatment planning. Nine patients were treated after incomplete tumor resection, 8 patients after tumor biopsy only, and 29 patients after tumor recurrence following gross total (10/29 patients) or progression after subtotal (19/29 patients) resection. All patients were classified as benign meningioma on review slides at MGH. The median dose to the macroscopic gross tumor volume was 59.0 CGE (range 53.1-74.1 CGE, CGE = proton Gy x 1.1 RBE). The median follow-up was 53 months (range 12-207). RESULTS: Overall survival at 5 and 10 years was 93 and 77%, respectively, and the recurrence-free rate at 5 and 10 years was 100% and 88%, respectively. Survival without severe toxicity was 80% at 5 and 10 years. Three patients presented with local tumor recurrence at 61, 95, and 125 months. One patient developed distant intradural metastasis at 21 and 88 months. No patient died from recurrent meningioma; however, 4 patients died of other causes. A fifth patient died from a brainstem necrosis after 22 months. Eight patients developed severe long-term toxicity from radiotherapy, including ophthalmologic (4 patients), neurologic (4 patients), and otologic (2 patients) complications. All patients with ophthalmologic toxicity received doses higher than those allowed for the optic nerve structures in the current protocol. CONCLUSION: Combined proton and photon radiotherapy is an effective treatment for patients with recurrent or incompletely resected benign intracranial menigiomas. Observed toxicity appears to be dose-related; with currently employed dose constraints, toxicity should not exceed that seen in patients treated with conformal fractionated supervoltage photon radiotherapy.

Adolescent↗
PubMedDate not supplied

Magnetic resonance angiography of the peripheral vessels in patients with peripheral arterial occlusive disease: when is an additional conventional angiography required?

The purpose of this work was to find out how often the clinician asks for a conventional angiography (CA) in patients with peripheral arterial occlusive disease (PAOD) after a magnetic resonance angiography (MRA) has been performed and how often the CA reveals additional information for therapy planning. Quality criteria for the MRA were defined and tested to see whether they can predict the need for an additional CA. In this prospective study, 81 patients suffering from PAOD (Fontaine classification IIa, n = 13; IIb, n = 33; III, n = 10; IV, n = 25) were examined with a 1.5-T MR-scanner with dedicated coils using a step-by-step technique. The vascular surgeon decided whether he could plan the therapy on the basis of the MRA or if he needed an additional CA. The MRA was assessed in terms of the image quality of the MRA and regarding therapeutic management of the patient in a two-grade scale: sufficient and insufficient. In 27/81 (33%) patients, the clinician asked for a CA, which revealed new information in only 11 patients. The relative number of MRAs with insufficient image quality was significantly higher (p < 0.01) in the group with additional information on CA (8/11) compared to the group without additional information (0/16). The assessment of an MRA based on image quality and regarding therapeutic management of the patient might reduce the number of CAs for therapy planning in patients with PAOD.

Aged↗