Peter Hallscheidt
Publications
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1.27Impact points
Accuracy of MRI with an endorectal coil for staging endometrial cancer.
Acta radiologica (Stockholm, Sweden : 1987). 04/2012;
BackgroundThe very good results of magnetic resonance imaging (MRI) using an endorectal coil in staging prostate cancer at 1.5T suggested that this imaging technique might be able to be used to stage endometrial cancer, the most common tumor in postmenopausal women.PurposeTo evaluate the accuracy of... [more] BackgroundThe very good results of magnetic resonance imaging (MRI) using an endorectal coil in staging prostate cancer at 1.5T suggested that this imaging technique might be able to be used to stage endometrial cancer, the most common tumor in postmenopausal women.PurposeTo evaluate the accuracy of MRI with an endorectal surface coil for staging primary endometrial carcinoma.Material and MethodsA total of 33 consecutive patients with biopsy-proven endometrial cancer underwent 1.5T MRI with an endorectal surface coil (eMRI) using sagittal and axial T2-weighted (T2w) turbo spin echo (TSE), axial T1 gradient echo 2D fat-saturated (fs), sagittal T1 gradient echo 3D with and without contrast enhancement (CE), and axial T1 TSE fs CE sequence. Evaluation of local tumor extension was based on the revised standard TNM classification for endometrial cancer. eMRI staging was compared with the histopathological results after surgery.ResultsA total of 33 consecutive patients underwent eMRI for staging endometrial cancer, and 21 of these underwent primary surgery. The histological stages were as follows: T1a (n = 8), T1b (n = 10), T2b (n = 2), and T3a (n = 1). Overall staging accuracy by eMRI was 71% (15 of 21). With regard to depth of myometrial invasion, eMRI correctly diagnosed stage T1a in 75% (6/8) and stage T1b in 80% (8/10). eMRI overstaged the tumor in four patients and understaged it in two.ConclusioneMRI is highly accurate in staging myometrial invasion. However, eMRI at 1.5T does not seem to be significantly more accurate than pelvic MRI without an endorectal coil at 1.5T for staging primary endometrial cancer. eMRI for endometrial carcinoma therefore might not meet expectations compared with the results obtained using eMRI for staging prostate cancer at 1.5T.
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2.65Impact points
Investigation of renal lesions by diffusion-weighted magnetic resonance imaging applying intravoxel incoherent motion-derived parameters-Initial experience.
European journal of radiology. 11/2011; 81(3):e310-6.
Usefulness of biexponentially fitted signal attenuation at different b-values for differentiating the histological characteristics of renal tumors. A total of 26 patients with 28 renal masses (histologically proven: 20 clear cell renal cell carcinomas [ccRCC], three transitional cell carcinomas, two... [more] Usefulness of biexponentially fitted signal attenuation at different b-values for differentiating the histological characteristics of renal tumors. A total of 26 patients with 28 renal masses (histologically proven: 20 clear cell renal cell carcinomas [ccRCC], three transitional cell carcinomas, two oncocytomas, and one papillary RCC) and 30 volunteers with healthy kidneys were examined at 1.5Tesla using an echo-planar DWI sequence. Using the IVIM model, we calculated the perfusion fraction f and the diffusion coefficient D. Furthermore, the ADC was obtained. These tumor parameters were compared to healthy renal tissue nonparametrically, and a receiver operating characteristic (ROC) analysis was performed. Healthy renal parenchyma showed higher ADC and D values (p<0.001) than ccRCC (ADC 1.95±0.10 [SD]μm(2)/ms, f 18.32±2.52%, and D 1.88±0.11μm(2)/ms versus ADC 1.45±0.38μm(2)/ms, f 18.59±6.16%, and D 1.34±0.38μm(2)/ms). When detecting malignancies the area under the curve for D was higher than for ADC. The f values for ccRCC were higher (p<0.001) than for non-ccRCC (ADC 1.52±0.47μm(2)/ms, f 8.44±1.24%, and D 1.30±0.18μm(2)/ms). Both f and D correlated with ccRCC grading. IVIM imaging is able to provide reliable diffusion values in the human kidney and may enhance the accuracy of tumor diagnosis. The D value was the best parameter to distinguish renal tumors from healthy renal tissue. The f value is promising for determining the histological subgroups.
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3.78Impact points
Imaging of female pelvic malignancies regarding MRI, CT, and PET/CT: Part 2.
Strahlentherapie und Onkologie : Organ der Deutschen Röntgengesellschaft ... [et al]. 11/2011; 187(11):705-14.
To compose diagnostic standard operating procedures for both clinical and imaging assessment for vulvar and vaginal cancer, for vaginal sarcoma, and for ovarian cancer. The literature was reviewed for diagnosing the above mentioned malignancies in the female pelvis. Special focus herein lies in tumo... [more] To compose diagnostic standard operating procedures for both clinical and imaging assessment for vulvar and vaginal cancer, for vaginal sarcoma, and for ovarian cancer. The literature was reviewed for diagnosing the above mentioned malignancies in the female pelvis. Special focus herein lies in tumor representation in MRI, followed by the evaluation of CT and PET/CT for this topic. MRI is a useful additional diagnostic complement but by no means replaces established methods of gynecologic diagnostics and ultrasound. In fact, MRI is only implemented in the guidelines for vulvar cancer. According to the current literature, CT is still the cross-sectional imaging modality of choice for evaluating ovarian cancer. PET/CT appears to have advantages for staging and follow-up in sarcomas and cancers of the ovaries.
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2.23Impact points
Long-term remission in a patient with heavily pretreated, advanced ovarian cancer achieved by bevacizumab and metronomic cyclophosphamide treatment.
Anti-cancer drugs. 11/2011; 22(10):1030-3.
Vascular endothelial growth factor seems to be a promoter of tumor progression for epithelial ovarian cancer. New drugs such as bevacizumab, either alone or in combination with metronomic chemotherapy, suppress tumor growth and have proved to be effective in various tumor types. We present a 60-year... [more] Vascular endothelial growth factor seems to be a promoter of tumor progression for epithelial ovarian cancer. New drugs such as bevacizumab, either alone or in combination with metronomic chemotherapy, suppress tumor growth and have proved to be effective in various tumor types. We present a 60-year-old patient with heavily pretreated, recurrent epithelial ovarian cancer, who received bevacizumab (10 mg/m(2)) every 2 weeks in combination with metronomic administered low-dose cyclophosphamide (50 mg/day orally) after failing four explorative laparotomies and multiple chemotherapy regimes. At the time of writing, February 2011, she was being treated with this combination therapy for 24 months and the progression-free survival still continues. Treatment of advanced, refractory epithelial ovarian cancer with bevacizumab in combination with low-dose cyclophosphamide could be a very effective salvage treatment option in heavily pretreated patients.
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3.78Impact points
Imaging of female pelvic malignancies regarding MRI, CT, and PET/CT : part 1.
Strahlentherapie und Onkologie : Organ der Deutschen Röntgengesellschaft ... [et al]. 09/2011; 187(10):611-8.
The goal of this article is to provide an overview of diagnostic standard operating procedures for both clinical and imaging assessment of cervical and endometrial carcinoma, sarcoma of the uterus, and primary pelvic non-Hodgkin's lymphoma. The literature was reviewed for methods used to diagnos... [more] The goal of this article is to provide an overview of diagnostic standard operating procedures for both clinical and imaging assessment of cervical and endometrial carcinoma, sarcoma of the uterus, and primary pelvic non-Hodgkin's lymphoma. The literature was reviewed for methods used to diagnose malignancies in the female pelvis with a special focus on the role of MRI as the imaging method of choice. Furthermore, CT findings and staging criteria for the mentioned malignancies are also provided. Whereas ultrasound still remains the imaging modality of choice in clinical practice for the early diagnosis of female pelvic malignancies, MRI is more frequently recognized as a diagnostic tool for its accuracy in tumor identification. MRI also plays a crucial role in the 3D pretreatment planning for brachytherapy especially in cervical cancer. In the future, PET/CT might achieve an important role for staging lymph nodes or distant metastases as well as tumor recurrence.
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1.58Impact points
Short-range clinical, dynamic magnetic resonance imaging and P-QOL questionnaire results after mesh repair in female pelvic organ prolapse.
European journal of obstetrics, gynecology, and reproductive biology. 04/2011; 157(1):107-12.
To evaluate clinical, quality-of-life (QoL) and dynamic magnetic resonance imaging (dMRI) results in patients with pelvic organ prolapse (POP) preoperatively, and 4 and 12 weeks after anterior and/or posterior mesh repair. Thirty-six patients (mean age 65 years) with symptomatic pelvic floor descent... [more] To evaluate clinical, quality-of-life (QoL) and dynamic magnetic resonance imaging (dMRI) results in patients with pelvic organ prolapse (POP) preoperatively, and 4 and 12 weeks after anterior and/or posterior mesh repair. Thirty-six patients (mean age 65 years) with symptomatic pelvic floor descent underwent mesh repair. The prolapse was quantified using the POP-Q system. Before surgery as well as 4 and 12 weeks after surgery, the pelvic organ positions were measured on dynamic magnetic resonance imaging during Valsalva manoeuvre in relation to the pubococcygeal and mid-pubic lines to assess surgery outcome. Patients also completed the P-QOL questionnaire to evaluate subjective changes at each visit. Four and 12 weeks after surgery patients showed improvement of the POP on clinical examination and on dynamic MRI. The latter demonstrated high significance (p<0.001) especially in bladder and vaginal cuff/cervix positions during maximal straining. All quality-of-life domains and some symptom questions of the P-QOL questionnaire significantly improved (p<0.05) 12 weeks after surgery. Significant anatomical and quality-of-life improvement was demonstrated after anterior and/or posterior mesh repair for POP using dynamic MRI and the P-QOL questionnaire.
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3.31Impact points
Multimedia article. Navigated renal access using electromagnetic tracking: an initial experience.
Surgical endoscopy. 04/2011; 25(4):1307-12.
Navigation systems are promising tools for improving efficacy and safety in surgical endoscopy and other minimally invasive techniques. The aim of the current study is to investigate electromagnetic tracking (EMT) for navigated renal access in a porcine model. For our proof-of-principle study we mod... [more] Navigation systems are promising tools for improving efficacy and safety in surgical endoscopy and other minimally invasive techniques. The aim of the current study is to investigate electromagnetic tracking (EMT) for navigated renal access in a porcine model. For our proof-of-principle study we modified a recently established porcine ex vivo model. Via a ureteral catheter which was placed into the desired puncture site, a small sensor was introduced and located by EMT. Then, a tracked needle was navigated into the collecting system in a "rendezvous" approach. A total of 90 renal tracts were obtained in six kidneys using EMT, with a maximum of three punctures allowed per intervention. For each puncture, number of attempts to success, final distance to probe, puncture time, and localization were assessed. We compared absolute and relative frequencies using the chi-square test and applied the Mann-Whitney U-test for continuous variables. No major problems were encountered performing the experiment. Access to the collecting system was successfully obtained after a single puncture in 91% (82/90) and within a second attempt in the remaining 9% (8/90). Thus, a 100% success rate was reached after a maximum of two punctures. Location of the calyx did not have a significant effect on success rate (p = 0.637). After a learning phase of 30 punctures, higher success rate (96% versus 83%; p = 0.041) was accomplished within shorter puncture time (14 versus 17 s; p = 0.049) and with higher precision (1.7 versus 2.8 mm; p < 0.001). With respect to other established techniques, use of EMT seems to decrease the number of attempts and procedural time remarkably. This might contribute to greater safety and efficacy when applied clinically. The presented approach appears to be promising, especially in difficult settings, provided that in vivo data support these initial results.
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4.02Impact points
Selective transarterial embolization for posttraumatic renal hemorrhage: a second try is worthwhile.
The Journal of urology. 03/2011; 185(5):1751-5.
Selective percutaneous transarterial embolization has proved to be effective, safe treatment for posttraumatic renal hemorrhage but inefficacious procedures often lead to nephrectomy. Thus, the success rate of transarterial embolization should be maximized. We retrospectively investigated the clinic... [more] Selective percutaneous transarterial embolization has proved to be effective, safe treatment for posttraumatic renal hemorrhage but inefficacious procedures often lead to nephrectomy. Thus, the success rate of transarterial embolization should be maximized. We retrospectively investigated the clinical success rate of transarterial embolization for posttraumatic bleeding. Study inclusion criteria were imaging evidence and clinical signs of hemorrhage or a hemoglobin decrease of more than 2 gm/dl in urological cases. We excluded spontaneous bleeding from analysis. A total of 21 patients with a median age of 66 years (range 12 to 78) met study inclusion criteria. Etiology was blunt trauma in 3 cases (14%), stab wound in 1 (5%) and an iatrogenic cause in 17 (81%). In 2 patients an active bleeding site could not be detected during selective angiography. Transarterial embolization was done in 19 patients and led to primary clinical success in 12 (63%), including 2 with grade V parenchymal injury. In 6 of 7 cases (86%) in which primary treatment failed transarterial embolization was repeated. It resulted in clinical success in 4 of 6 patients (67%) with equal efficiency (p =1). Three patients (16%) who could not be sufficiently treated with transarterial embolization underwent nephrectomy. When conservative measures fail and clinical symptoms or a relevant hemoglobin decrease occur, transarterial embolization should be considered. Since the success rate is equally high for initial and repeat interventions, re-intervention is justified when the clinical course allows.
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1.59Impact points
A young man with position-dependent erectile dysfunction: diagnostic work-up and interventional therapy of an arteriovenous malformation.
Clinics (São Paulo, Brazil). 01/2011; 66(6):1119-21.
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2.20Impact points
Preoperative tumor studies using MRI or CT in patients with clinically suspected insulinoma.
Pancreatology : official journal of the International Association of Pancreatology (IAP) ... [et al.]. 01/2011; 11(5):487-94.
Insulinomas are rare tumors that originate from the islet cells of the pancreas. The aims of this study were to localize insulinomas preoperatively using CT and/or MRI in correlation with postoperative pathological results. Between December 2001 and June 2010, 27 consecutive patients with clinically... [more] Insulinomas are rare tumors that originate from the islet cells of the pancreas. The aims of this study were to localize insulinomas preoperatively using CT and/or MRI in correlation with postoperative pathological results. Between December 2001 and June 2010, 27 consecutive patients with clinically suspected insulinoma were surgically treated in our university hospital. Preoperative CT (14 of 27 patients) and MRI studies (14 of 27 patients, one patient had both MRI and CT), operation reports, intraoperative ultrasonography reports, and pathological diagnoses were analyzed retrospectively. For each lesion, images were analyzed based on the presence of enhancement or the characteristics of signal intensities. Pathologic correlation was available for all the lesions. The female: male ratio was 2.9, with a mean age of 47.5 years (range 12-82) . Preoperative tumor localization was achieved by means of MRI and CT. A focal pancreatic lesion, which was hypointense on T(1)-weighted sequences, was detected on all the MR images (14 of 27 patients; 100%). These lesions were isointense (4 cases) to slightly hyperintense (10 of 14 cases) on T(2)-weighted sequences. In T(1)-weighted fat-suppressed contrast-enhanced sequences, there were two types of enhancement: homogeneously hyperintense lesions (in 10 of 14 cases) or peripherally hyper-, centrally isointense (in 4 of 14 cases). On all the CT images (14 of 27 patients), there was no detectable lesion on precontrast series; on arterial series in 13 of 14 patients (arterial series has not been done in one patient), lesions enhanced hypervascular in contrast to the rest of the pancreas with a mean enhancement of 147 HU (range 113-248) and 95 HU (range 65-141), respectively. On venous series in 13 of 14 patients (venous series has not been done in one patient), there was an enhanced lesion in contrast to the rest of the pancreas with a mean enhancement of 110 HU (range 91-151) and 86 HU (range 65-137), respectively. Intraoperative ultrasonography was performed in 11 of 27 patients to localize the tumor, which correlated with the results of the mentioned preoperative studies. Tumor size ranged from 9 × 11 to 31 × 37 mm. Enucleation was carried out in 14 patients, Whipple in 5, segmental resection in 3 and left distal pancreatectomy in 5 patients. The mortality rate was 0. Pathological findings were insulinoma or neuroendocrine tumors in 26 of 27 cases. One patient had a pathological finding of chronic pancreatic disease with intraepithelial neoplasia (grade 1A). We conclude that the preoperative localization of insulinoma in clinically suspected patients can be made on the basis of MRI and/or CT studies. A hallmark lesion is hypointense in T(1)-weighted sequences, homogeneously or peripherally hyperintense in T(1)-weighted fat-suppressed contrast-enhanced sequence using MRI (100% of cases) or/and a hypervascular enhanced lesion on arterial (100% of CT studies) and on venous series using CT (66.7% of CT studies).
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2.65Impact points
Combined CT- and fluoroscopy-guided nephrostomy in patients with non-obstructive uropathy due to urine leaks in cases of failed ultrasound-guided procedures.
European journal of radiology. 10/2010; 80(3):686-91.
To report our experience of combined CT- and fluoroscopy-guided nephrostomy in patients with non-obstructive uropathy due to urine leaks in cases of failed ultrasound-guided procedures. Eighteen patients (23 kidneys) with non-obstructive uropathy due to urine leaks underwent combined CT- and fluoros... [more] To report our experience of combined CT- and fluoroscopy-guided nephrostomy in patients with non-obstructive uropathy due to urine leaks in cases of failed ultrasound-guided procedures. Eighteen patients (23 kidneys) with non-obstructive uropathy due to urine leaks underwent combined CT- and fluoroscopy-guided nephrostomy. All procedures were indicated as second-line interventions after failed ultrasound-guided nephrostomy. Thirteen males and five females with an age of 62.3±8.7 (40-84) years were treated. Urine leaks developed in majority after open surgery, e.g. postoperative insufficiency of ureteroneocystostomy (5 kidneys). The main reasons for failed ultrasound-guided nephrostomy included anatomic obstacles in the puncture tract (7 kidneys), and inability to identify pelvic structures (7 kidneys). CT-guided guidewire placement into the collecting system was followed by fluoroscopy-guided nephrostomy tube positioning. Procedural success rate, major and minor complication rates, CT-views and needle passes, duration of the procedure and radiation dose were analyzed. Procedural success was 91%. Major and minor complication rates were 9% (one septic shock and one perirenal abscess) and 9% (one perirenal haematoma and one urinoma), respectively. 30-day mortality rate was 6%. Number of CT-views and needle passes were 9.3±6.1 and 3.6±2.6, respectively. Duration of the complete procedure was 87±32 min. Dose-length product and dose-area product were 1.8±1.4 Gy cm and 3.9±4.3 Gy cm2, respectively. Combined CT- and fluoroscopy-guided nephrostomy in patients with non-obstructive uropathy due to urine leaks in cases of failed ultrasound-guided procedures was feasible with high technical success and a tolerable complication rate.
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1.95Impact points
Patients with life-threatening arterial renal hemorrhage: CT angiography and catheter angiography with subsequent superselective embolization.
Cardiovascular and interventional radiology. 06/2010; 33(3):498-508.
The purpose of this study was to evaluate the technical and clinical success of superselective embolization in patients with life-threatening arterial renal hemorrhage undergoing preinterventional CT angiography. Forty-three patients with clinical signs of life-threatening arterial renal hemorrhage ... [more] The purpose of this study was to evaluate the technical and clinical success of superselective embolization in patients with life-threatening arterial renal hemorrhage undergoing preinterventional CT angiography. Forty-three patients with clinical signs of life-threatening arterial renal hemorrhage underwent CT angiography and catheter angiography. Superselective embolization was indicated in the case of a positive catheter angiography. Primary study goals were technical and clinical success of superselective embolization. Secondary study goals were CT angiographic and catheter angiographic image findings and clinical follow-up. The mean time interval between CT angiography and catheter angiography was 8.3 +/- 10.3 h (range, 0.2-34.1 h). Arterial renal hemorrhage was identified with CT angiography in 42 of 43 patients (98%) and catheter angiography in 39 of 43 patients (91%) (overview angiography in 4 of 43 patients [9%], selective angiography in 16 of 43 patients [37%], and superselective angiography in 39 of 43 patients [91%]). Superselective embolization was performed in 39 of 43 patients (91%) and technically successful in 37 of 39 patients (95%). Therefore, coil embolization was performed in 13 of 37 patients (35%), liquid embolization in 9 of 37 patients (24%), particulate embolization in 1 of 37 patients (3%), and a combination in 14 of 37 patients (38%). Clinical failure occurred in 8 of 39 patients (21%) and procedure-related complications in 2 of 39 patients (5%). The 30-day mortality rate was 3%. Hemoglobin decreased significantly prior to intervention (P < 0.001) and increased significantly after intervention (P < 0.005). In conclusion, superselective embolization is effective, reliable, and safe in patients with life-threatening arterial renal hemorrhage. In contrast to overview and selective angiography, only superselective angiography allows reliable detection of arterial renal hemorrhage. Preinterventional CT angiography is excellent for detection and localization of arterial renal hemorrhage and appropriate for guidance of the embolization procedure.
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2.87Impact points
Risk factors and clinical management of haemorrhage after open nephron-sparing surgery.
BJU international. 03/2010; 106(10):1488-93.
To identify risk factors for relevant haemorrhage after open nephron-sparing surgery (NSS) for renal cell carcinoma, and to evaluate its clinical management. We evaluated bleeding complications after open NSS in 196 consecutive cases (193 patients) at our institution. The median (range) age of the p... [more] To identify risk factors for relevant haemorrhage after open nephron-sparing surgery (NSS) for renal cell carcinoma, and to evaluate its clinical management. We evaluated bleeding complications after open NSS in 196 consecutive cases (193 patients) at our institution. The median (range) age of the patients was 64 (3-91) years and the tumour diameter was 2.7 (0.5-11.8) cm. Sex, age, body mass index, imperative vs elective indication, year of surgery, multifocality, tumour diameter and malignant vs benign pathology were tested exploratively and significant variables entered in a multivariate model. The clinical management of haemorrhage after NSS was analysed. Bleeding required conservative (six), interventional (six) or surgical (three) therapy in 15 of the 196 cases (8%). Imperative indication (P= 0.043) and multifocality (P= 0.039) were independent risk factors in a multivariate model. Compared with superselective percutaneous transarterial embolization (TAE), surgery as a primary therapeutic option was more likely within 24 h after NSS (P= 0.012). Bleeding was finally controlled in all patients, while the kidney was preserved in 11 patients. There was only a minor decline of renal function at the 3-month follow-up. We identified multifocal tumours and imperative indication as risk factors for haemorrhage after NSS. The management was very successful, relying on TAE as an effective and safe treatment for bleeding after NSS. In rare cases of severe bleeding surgical exploration is unavoidable, with a lower chance of kidney preservation.
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0.33Impact points
[Tumours of the Kidney: CT vs. MRI. Nearly equal alternatives with minor differences].
Der Urologe. Ausg. A. 02/2010; 49(3):345-50.
Because of progress in imaging, the incidence of renal tumours, especially small lesions, has been rising over the last years. Therefore, imaging must be done to decide how to proceed further. But which is the most effective modality: computed tomography (CT) or magnetic resonance imaging (MRI)? Fro... [more] Because of progress in imaging, the incidence of renal tumours, especially small lesions, has been rising over the last years. Therefore, imaging must be done to decide how to proceed further. But which is the most effective modality: computed tomography (CT) or magnetic resonance imaging (MRI)? From the technical point of view, the two alternatives appear to be nearly equal. Multidetector CT remains the reference standard for staging and lesion characterisation, whereas MRI is the method of choice for determining caval extension of a tumour thrombus and infiltration of the renal vein. If an accurate diagnosis cannot be specified, the remaining modality should be used complementarily.
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4.02Impact points
Intrarenal artery delineation with ultra high resolution, flat panel based, volume computerized tomography: outer limits of spatial resolution.
The Journal of urology. 12/2009; 182(6):2915-9.
PURPOSE: New methods of noninvasive high resolution imaging may improve the delineation of tumor microvessels and, thus, be of significant help in surgical planning and cost-effective monitoring of novel anti-angiogenic therapy. We determined the maximum delineation of intrarenal microvessels with a... [more] PURPOSE: New methods of noninvasive high resolution imaging may improve the delineation of tumor microvessels and, thus, be of significant help in surgical planning and cost-effective monitoring of novel anti-angiogenic therapy. We determined the maximum delineation of intrarenal microvessels with a novel flat panel based volume computerized tomography system in an experimental setting. MATERIALS AND METHODS: We prospectively evaluated 13 porcine renal specimens for intrarenal vessel delineation using a prototype gantry based, flat panel, cone beam computerized tomography system. The gantry incorporates an array of a 40 x 30 cm(2) CsI amorphous silicon flat panel detector consisting of a 2,048 x 1,536 matrix. After catheterizing the renal artery with a 5Fr end hole catheter a contrast enhanced scan was performed using BaS as contrast medium at a dilution of 200 mg/ml. The diameter of all definable arterial branches was determined using a software tool based on Medical Imaging and Interaction Toolkit, allowing semi-automatic segmentation of the vessel tree. In step 1 the vessel tree is segmented by a 3-dimensional region growing algorithm. Following its medial axis the vessel tree is extracted and converted to a representation, including the diameter of the vessels. RESULTS: In each kidney an average +/- SD of 47,454 +/- 22,382 arterial branches could be delineated. The diameter of the branches was 0.029 (mean 0.032 +/- 0.0025) to 3.444 mm (mean 1.813 +/- 0.6139) with a median of 0.263 mm. Of visible intrarenal arteries 2.7% had a vessel diameter of 0.029 mm. CONCLUSIONS: Flat panel based volume computerized tomography can visualize intrarenal microvessels down to a diameter of 0.03 mm. It may improve the assessment of renal microvessel architecture in healthy patients and in those with pathological conditions.
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3.23Impact points
An expandable catheter loop coil for intravascular MRI in larger blood vessels.
Magnetic resonance in medicine : official journal of the Society of Magnetic Resonance in Medicine / Society of Magnetic Resonance in Medicine. 11/2009;
The present study proposes a catheter system with an expandable coil etched on a polyimide foil. The catheter system combines the advantages of a small insertion diameter when the coil is rolled up in a protective carrier sheath with an increased signal-to-noise ratio (SNR) and penetration depth whe... [more] The present study proposes a catheter system with an expandable coil etched on a polyimide foil. The catheter system combines the advantages of a small insertion diameter when the coil is rolled up in a protective carrier sheath with an increased signal-to-noise ratio (SNR) and penetration depth when the coil is pushed out. After imaging, the coil can be retracted into the sheath and folded back into the initial rolled-up configuration due to the tapered geometry of the carrier foil. The catheter system was tested on two healthy anesthetized pigs, including tracking and high-resolution intravascular imaging. To reduce artifacts in high-resolution images induced by catheter motion in the pulsatile blood flow, a motion-gating method was implemented that combines a flow-compensated two-dimensional fast low angle shot (FLASH) imaging sequence with the acquisition of projection data for retrospective gating. Using the projection data for motion detection, image SNR was increased by up to 500% over uncorrected images, and anatomic structures of 150 mum size could be differentiated in the aorta. Magn Reson Med, 2009. (c) 2009 Wiley-Liss, Inc.
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2.65Impact points
Tumor perfusion assessed by dynamic contrast-enhanced MRI correlates to the grading of renal cell carcinoma: Initial results.
European journal of radiology. 06/2009;
In this study, we investigated whether assessment of the tumor perfusion by dynamic contrast-enhanced magnetic resonance imaging (DCE MRI) enables to estimate the morphologic grading of renal cell carcinomas. A total of 21 patients with suspected renal cell cancer were examined using a Gadobutrol-en... [more] In this study, we investigated whether assessment of the tumor perfusion by dynamic contrast-enhanced magnetic resonance imaging (DCE MRI) enables to estimate the morphologic grading of renal cell carcinomas. A total of 21 patients with suspected renal cell cancer were examined using a Gadobutrol-enhanced, dynamic saturation-recovery, turbo-fast, low-angle shot sequence. Tumor perfusion and the tissue-blood ratio within the entire tumor and the most highly vascularized part of the tumor were calculated according to the model of Miles. Immediately after examination, patients underwent surgery, and the results from imaging were compared with the morphological analysis of the histologic grading. Fourteen patients had G2 tumors, and seven patients had G3 tumors. Significantly higher perfusion values (p<0.05) were obtained in G3 tumors than in G2 tumors when the entire tumor area was considered (1.59+/-0.44(ml/g/min) vs. 1.08+/-0.38(ml/g/min)) or its most highly vascularized part (2.14+/-0.89(ml/g/min) vs. 1.40+/-0.49(ml/g/min)). By contrast, the tissue-blood ratios did not differ significantly between the two groups. In conclusion, unlike tissue-blood ratio, surrogate parameters of the tumor perfusion determined by DCE MRI seem to allow an estimation of the grading of renal cell carcinoma. However, further studies with high case numbers and including patients with G1 tumors are required to evaluate the full potential and clinical impact.
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1.95Impact points
Analysis of Nontarget Embolization Mechanisms During Embolization and Chemoembolization Procedures.
Cardiovascular and interventional radiology. 05/2009;
Complications of embolization and chemoembolization remain a problem even with the development of low-profile catheter material and the introduction of new embolization agents. In recent years many new embolization materials have become available for clinical use, so the possibilities and limitation... [more] Complications of embolization and chemoembolization remain a problem even with the development of low-profile catheter material and the introduction of new embolization agents. In recent years many new embolization materials have become available for clinical use, so the possibilities and limitations of these new materials must be understood to allow safe and effective embolization. Although up to now some scientific work has been published reporting the basic risk of embolization procedures, the underlying pathomechanism remains the object of speculation. Besides complications like drug toxicity, allergic reactions, and bleeding of the puncture site, the characteristics of embolization materials must be known to understand the potential complications of nontarget embolization and reflux of embolization material. This article gives an overview of established and new embolization materials, their potential risks, and the underlying pathophysiology.
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7.54Impact points
Vessel fractions in tumor xenografts depicted by flow- or contrast-sensitive three-dimensional high-frequency Doppler ultrasound respond differently to antiangiogenic treatment.
Cancer research. 10/2008; 68(17):7042-9.
High-frequency volumetric Power Doppler ultrasound (HF-VPDU) captures flow-dependent signals in blood vessels and can be used to assess antiangiogenic therapy effects in rodent tumors. However, the sensitivity is limited to vessels larger than capillaries. Contrast-enhanced HF-VPDU reveals all perfu... [more] High-frequency volumetric Power Doppler ultrasound (HF-VPDU) captures flow-dependent signals in blood vessels and can be used to assess antiangiogenic therapy effects in rodent tumors. However, the sensitivity is limited to vessels larger than capillaries. Contrast-enhanced HF-VPDU reveals all perfused vessels by assessing stimulated acoustic emissions from disintegrating microbubbles. Thus, we investigated whether flow-sensitive and contrast-enhanced HF-VPDU can depict different vessel fractions and assess their early response to antiangiogenic therapy. Mice with A431 tumors were scanned before and after administration of polybutylcyanoacrylate microbubbles by HF-VPDU. Animals received either antiangiogenic treatment (SU11248) or a control substance and were imaged repeatedly over 9 days. At each time point, tumors were removed for immunohistochemical analysis. During growth of untreated tumors, vascularization decreased correspondingly on flow-sensitive and contrast-enhanced scans. Treated tumors showed a significantly (P < 0.05) stronger decline in vascularization than controls, which was more pronounced in contrast-enhanced scans. Surprisingly, whereas vascularization remained low in contrast-enhanced scans, flow-sensitive ultrasound indicated a reincrease after day 6 with a higher vascularization than the controls at day 9. Histologic evaluation indicated that immature vessels degraded markedly on therapy, whereas large mature vessels on the tumor periphery were more therapy resistant and drew closer due to tumor shrinkage. In conclusion, contrast-enhanced HF-VPDU and flow-sensitive HF-VPDU are both capable of assessing the effects of antiangiogenic therapy. Because contrast-sensitive ultrasound is more sensitive for small immature vessels and flow-sensitive ultrasound mostly captures large vessels at the tumor periphery, the combination of both methods can provide evidence of vascular maturity in tumors.
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1.32Impact points
Morphine-induced acute lung injury.
Journal of clinical anesthesia. 07/2008; 20(4):300-3.
A 38-year-old woman who had familial adenomatous polyposis was admitted to the intensive care unit with an episode of severe sepsis 5 days after undergoing a pancreas-preserving duodenectomy. Laparotomy with removal of an intra-abdominal abscess, followed by closed postoperative continuous lavage fo... [more] A 38-year-old woman who had familial adenomatous polyposis was admitted to the intensive care unit with an episode of severe sepsis 5 days after undergoing a pancreas-preserving duodenectomy. Laparotomy with removal of an intra-abdominal abscess, followed by closed postoperative continuous lavage for 10 days, was performed. During two courses of planned tracheal extubation, the patient developed an acute lung injury, making a reintubation necessary. In both events, the patient received small doses of continuous morphine before the extubation. Morphine may induce the development of an acute lung injury in patients, whereas the exact pathophysiologic and pharmacologic mechanisms remain unclear.
Following (12)
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Michael Eichbaum
Universität Heidelberg -
Peter Schirmacher
University Hospital Heidelberg -
Hans-Peter Meinzer
Deutsches Krebsforschungszentrum -
Ingmar Wegner
Stryker Leibinger GmbH & Co. KG -
Soenke Bartling
German Cancer Research Center / UMC Mannheim
