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J. Kettenbach,
B. Pokrajac,
S. Schamp,
C. Fellner,
R. Schmid,
B. Gustorff,
J. Berger,
M. Grgurin,
K. Peer,
U. Wolff,
W. Seitz,
R. Pötter,
J. Lammer
[show abstract]
[hide abstract]
ABSTRACT: Fragestellung. Evaluierung der Machbarkeit und Effektivität einer MR-gestützten Brachytherapie nichtresektabler Lebermetastasen.
Methodik. In einer prospektiven Phase I/II Studie wurden Lebermetastasen (Durchmesser 0,8–5,2 cm) mittels interstitieller Brachytherapie
behandelt. Die Platzierung MR-kompatibler Brachytherapie-Applikatoren erfolgte im offenen 0,2-Tesla-MR-Tomographen (Magnetom
Open Viva, Siemens, Erlangen) mittels schneller T1-gewichteter Sequenzen. Evaluierung der Tumornekrose und Nachuntersuchungen
erfolgten an 1,5-Tesla-MRT-Geräten.
Ergebnisse. Anhand zweier Patienten werden Ergebnisse einer noch nicht publizierten prospektiven Studie exemplarisch diskutiert. Die
durchschnittliche Interventionszeit betrug 4,9 h. Akute und mittelfristig auftretende Nebenwirkungen waren akzeptabel. Bei
symptomatischen Metastasen (DM >5 cm) konnte eine vorübergehende Palliation erzielt werden. Bei kleinen Metastasen (DM 3 cm)
wurde eine Tumorkontrolle von bis zu 9 Monaten erzielt.
Schlussfolgerungen. Die MR-gestützte Brachytherapie ist machbar und hinsichtlich des technischen Erfolges ein effektives Verfahren zur Behandlung
von Lebermetastasen bis zu 3 cm Größe. Weitere methodische Verbesserungen sind erforderlich.
Purpose. To evaluate the feasibility and efficacy of MR-guided interstitial brachytherapy of non-resectable liver metastasis.
Methods. Liver metastases (0.8–5.2 cm in diameter) were treated during a prospective phase I/II study using an open 0.2 Tesla MR system
(Magnetom Open Viva, Siemens, Erlangen). MR-compatible brachytherapy applicators were placed percutaneously under MR-guidance
in an open 0,2 Tesla MR system (Magnetom Open Viva, Siemens, Erlangen) using fast T1-weighted sequences. Pretreatment and
follow-up studies were performed using a 1.5 Tesla MR system.
Results. Preliminary results of an unpublished prospective study are discussed exemplary on 2 selected patients. The median procedure
time was 4.9 h. No major complications were observed and late effects were acceptable. In large symptomatic metastases only
a temporary relief of pain was achieved. In smaller metastases (DM 3 cm) a tumor control was observed.
Conclusion. MR-guided brachytherapy is feasible and has the potential to ablate liver metastases with diameter of less than 3 cm. Further
developments are necessary.
Der Radiologe 04/2012; 41(1):56-63. · 0.61 Impact Factor
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[show abstract]
[hide abstract]
ABSTRACT: Background: Percutaneous liver tumour ablation has received increased attention as an effective treatment and has been published by
a large number of groups. A minimally invasive, percutaneous approach requires fewer resources, less time, recovery and cost,
and often offers reduced morbidity and mortality compared with more invasive methods. To be beneficial, however, image-guided
percutaneous radiofrequency (RF) therapy will have to meet those criteria without sacrificing efficacy.
Methods: Image-guided, local liver tumour treatment relies on the assumption that local disease control may improve survival. Recent
developments in ablative techniques are being applied to patients with inoperable, small, or solitary and recurrent metachronous
liver tumours.
Results: RF ablation of liver tumours with image-guided needle placement, either percutaneously, laparoscopically, or with open surgery,
has proven to be effective and encouraging results have been reported. Both intraoperative and percutaneous techniques, however,
are complementary options to successfully treat patients with liver tumours.
Conclusions: In this article, the authors review the technical developments and current status of liver tumour ablation using radiofrequency
ablation techniques, and conclude with a discussion of challenges and opportunities for the future.
Grundlagen: Die perkutane Zerstörung von Lebertumoren findet als effektives Verfahren zur Tumortherapie zunehmendes Interesse und wurde
von zahlreichen Arbeitsgruppen publiziert. Der minimal invasive perkutane Zugang erfordert einen geringeren Aufwand an Zeit,
Kosten oder Rehabilitation und weist im Vergleich mit invasiveren Verfahren eine oft geringere Morbidität und Mortalität auf.
Die bildgestützte, perkutane Radiofrequenzablation hat diese Kriterien, jedoch ohne an Effektivität einzubüßen.
Methodik: Die Anwendung bildgestützter Verfahren zur lokalen Tumortherapie geht davon aus, daß eine lokale Tumorkontrolle das Überleben
verlängert. Neuartige Entwicklungen auf dem Gebiet der Thermoablation ermöglichen die Zerstörung von inoperablen, kleinen
oder solitären, aber auch von rezidivierenden metachronen Lebertumoren.
Ergebnisse: Die Radiofrequenzablation von Lebertumoren mit bildgestützter Plazierung der Therapiesonden kann entweder perkutan, laparoskopisch
oder intraoperativ durchgeführt werden. Deren Anwendung und Wirksamkeit ist durch klinische Studien belegt. Die intraoperative
und perkutane Anwendung ergänzen sich dabei in der erfolgreichen Behandlung von Lebertumoren.
Schlußfolgerungen: Technische Entwicklungen und der derzeitige Stand der Anwendung der Radiofrequenzablation von Lebertumoren werden beschrieben.
Zusammenfassend werden Indikationen für die klinische Anwendung diskutiert.
European Surgery 04/2012; 34(6):326-331. · 0.28 Impact Factor
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J. Kettenbach,
K. Kuroda,
N. Hata,
P. Morrison,
N. J. McDannold,
D. Gering,
P. Saiviroonporn,
G. P. Zientara,
P. McL. Black,
R. Kikinis,
F. A. Jolesz
[show abstract]
[hide abstract]
ABSTRACT: Summary The purpose of this study was to monitor interstitial laser therapy (LITT) in palliative treatment of brain tumours by using temperature-sensitive MRI sequences and image-processing techniques in realtime. Three consenting patients with recurrent gliomas were treated with LITT (3–4.5 W, 3–6 min). Temperature sensitive monitoring was performed either by T1 weighted fast spin echo (FSE) sequences, combined with pixel subtraction, optical flow (OF) computation, or by spoiled gradient recalled (SPGR) sequences used for chemical shift-based imaging. Both sequences were applied at 0.5 T (Signa SRGE Medical System, Milwaukee, Wl, USA). Pixel subtraction identified thermal changes in brain tumours, but could not evaluate the temperature values as chemical-shift based imaging. OF computation displayed the predicted course of thermal changes and revealed that the rate of heat deposition can be anisotropic, which may be related to heterogeneous tumour structure and/or vascularisation. Local tumour control was achieved with laser energy deposition giving clinically stable conditions for several months. Carefully applied LITT and thermal monitoring may evolve as an alternative palliative concept for patients with end-stage cerebral gliomas, reducing clinical symptoms from circumscribed areas of pathology.
07/2009; 7(6):589-598.
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ABSTRACT: Although angioplasty and stent applications in the iliac vessels and the superficial femoral artery have become routine procedures, their usefulness for the treatment of lesions of the popliteal artery and the lower leg arteries is still under discussion. For the popliteal artery, limitations are mainly due to the high mechanical stress in this area, causing high traction forces. Moreover, beyond the occlusive atherosclerotic changes, specific pathological entities such as aneurysms, emboli, entrapment syndromes, and cystic adventitial disease have to be differentiated. There is hope that the development of innovative stent designs with high flexibility might overcome the limitations. For lesions of the lower leg arteries treatment with percutaneous transluminal angioplasty (PTA) has become the method of choice. However, stent designs as used for cardiac interventions have been adapted for their application below the knee, and first encouraging results may help to justify their broad use in the future. Regarding PTA, innovative equipment and techniques for the treatment of arterial lesions below the knee include dedicated, long, and very flexible balloons, cutting balloon cryoplasty, and laser angioplasty. Regarding stents, bare metal stents, stents with passive or active coatings, and bioabsorbable stents have all been successfully used.
Der Radiologe 12/2006; 46(11):948-54. · 0.61 Impact Factor
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ABSTRACT: Acute type B dissections accompanied by an intramural haematoma in the ascending aorta are rare. However, progression of the intramural haematoma in the ascending aorta poses risks for the patients, which are similar to those of type A dissections, including pericardial effusions and consecutive tamponade. To date, no clear treatment guidelines exist for these patients. We report on successful percutaneous endovascular stent-graft treatment of an acute type B dissection accompanied by an intramural haematoma in the ascending aorta as primary and sole form of treatment.
The Thoracic and Cardiovascular Surgeon 11/2006; 54(7):500-1. · 0.88 Impact Factor
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[show abstract]
[hide abstract]
ABSTRACT: To classify a liver tumor, image-guided percutaneous biopsy of a liver lesion is indicated. Using ultrasound (US) to guide a biopsy needle into a liver lesion has been proven useful and safe. If a lesion cannot be seen on US or the access to a lesion has been complicated by its position, CT-guided biopsy can be performed. If a lesion cannot be delineated on US or CT, MR-guided biopsy is recommended. Using hepatospecific contrast agents, the time span to delineate tumor tissue can be prolonged. To differentiate diffuse liver disease, transvenous biopsy under fluoroscopic control can be performed if a percutaneous biopsy is contraindicated. In recent years fine-needle aspiration biopsy has been increasingly replaced by coaxial 14-20 G core biopsy, which is a safe and efficient technique to classify liver lesions and has a low complication rate.
Der Radiologe 02/2005; 45(1):44-54. · 0.61 Impact Factor
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[show abstract]
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ABSTRACT: The liver is a common site for various benign and malignant focal lesions. The initial modality for assessing liver lesions is ultrasound or CT. MRI with its superior soft tissue contrast offers multiple advantages over other imaging modalities. Contrast agents have been developed that increase the detection rate and provide more specific information in comparison to unenhanced techniques. In the mean time three classes are available for MR imaging of the liver: extracellular gadolinium chelates, hepatobiliary and reticulo-endothelia, superparamagnetic agents. We describe in this review the most common focal lesions, their diagnostic possibilities, and the imaging protocols. Clinical use of these contrast agents facilitates detection and differential diagnosis of focal liver lesions that may help to avoid invasive procedures such as biopsy for lesion characterization.
Der Radiologe 01/2005; 44(12):1170-84. · 0.61 Impact Factor
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[show abstract]
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ABSTRACT: Zur definitiven Klrung der Dignitt und Tumorklasse einer Leberlsion ist eine bildgesteuerte perkutane Biopsie indiziert. Unter Verwendung der Sonographie ist das Verfahren treffsicher und einfach. Die computertomographiegezielte Biopsie ist wegen der berlagerungsfreien, reproduzierbaren Darstellung von Leberherden und ihren Nachbarstrukturen in vielen Fllen besser geeignet. Fr Lsionen, die sich weder mit Ultraschall noch mit CT biopsieren lassen, bietet sich die Magnetresonanztomographie an. Durch den Einsatz leberspezifischer Kontrastmittel kann das Zeitfenster zur Durchfhrung einer Biopsie verlngert werden. Zur Abklrung diffuser Lebererkrankungen wird bei kontraindizierter perkutaner Biopsie eine transvense Leberbiopsie unter Durchleuchtung empfohlen. Die in den 1980er Jahren propagierte Feinnadelaspirationsbiopsie wurde zunehmend durch Stanzbiopsien (Durchmesser 14–20gg) in koaxialer Technik ersetzt, da diese eine zuverlssige artdiagnostische Klassifikation bei niedriger Komplikationsrate ermglichen.To classify a liver tumor, image-guided percutaneous biopsy of a liver lesion is indicated. Using ultrasound (US) to guide a biopsy needle into a liver lesion has been proven useful and safe. If a lesion cannot be seen on US or the access to a lesion has been complicated by its position, CT-guided biopsy can be performed. If a lesion cannot be delineated on US or CT, MR-guided biopsy is recommended. Using hepatospecific contrast agents, the time span to delineate tumor tissue can be prolonged. To differentiate diffuse liver disease, transvenous biopsy under fluoroscopic control can be performed if a percutaneous biopsy is contraindicated. In recent years fine-needle aspiration biopsy has been increasingly replaced by coaxial 14–20 G core biopsy, which is a safe and efficient technique to classify liver lesions and has a low complication rate.
Der Radiologe 12/2004; 45(1):44-54. · 0.61 Impact Factor
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[show abstract]
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ABSTRACT: In der Leber treten hufig benigne und maligne fokale Lsionen auf. Viele der gutartigen Vernderungen, wie simple Zysten, Hmangiome, fokal nodulre Hyperplasien (FNH) und Adenome, sind Zufallsbefunde. Ihre richtige Diagnose ist v.a. bei Patienten mit malignen Erkrankungen wichtig. Initiale Untersuchungsmethoden bei Leberlsionen sind meist Ultraschall oder CT. Die MRT nimmt aufgrund des hohen Weichteilkontrastes und der besseren Verfgbarkeit eine wichtige Rolle in der Abklrung von Lebertumoren ein. MRT-Kontrastmittel erhhen die Aussagekraft gegenber nativen Pulssequenzen. Zwischenzeitlich sind 3Klassen fr die Leberdiagnostik zugelassen: nichtspezifische extrazellulre, hepatobilire und superparamagnetische Kupffer-Zell-Kontrastmittel. In der vorliegenden Arbeit werden die hufigsten fokalen Leberlsionen, deren diagnostische Mglichkeiten und Untersuchungsprotokolle beschrieben. Durch Einsatz spezifischer Leberkontrastmittel zur Detektion und Differenzialdiagnose fokaler Lsionen knnen hufig Biopsien zur Charakterisierung der Leberlsionen vermieden werden.The liver is a common site for various benign and malignant focal lesions. The initial modality for assessing liver lesions is ultrasound or CT. MRI with its superior soft tissue contrast offers multiple advantages over other imaging modalities. Contrast agents have been developed that increase the detection rate and provide more specific information in comparison to unenhanced techniques. In the mean time three classes are available for MR imaging of the liver: extracellular gadolinium chelates, hepatobiliary and reticulo-endothelia, superparamagnetic agents. We describe in this review the most common focal lesions, their diagnostic possibilities, and the imaging protocols. Clinical use of these contrast agents facilitates detection and differential diagnosis of focal liver lesions that may help to avoid invasive procedures such as biopsy for lesion characterization.
Der Radiologe 11/2004; 44(12):1170-1184. · 0.61 Impact Factor
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[show abstract]
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ABSTRACT: To evaluate three-dimensional rotational digital subtraction angiography (3D-RDSA) in the embolization of the uterine artery in the treatment of symptomatic uterine leiomyomas (fibroids).
Eight women with complex pelvic vessel anatomy caused by large fibroids were embolized using 3D-RDSA. The raw data were sent to an external workstation, and video files with a resolution of one image/3 degrees and a scan range of 180 degrees in a surface-shaded display mode were produced. The primary goal was to assess an image intensifier angulation for the optimal visualization of the origin of the uterine artery. In addition, the intervention parameters were compared with those of 48 patients with standard angiography.
The analysis revealed no single angulation that can be recommended for standard angiography. No statistical differences were found between both groups concerning fluoroscopy time, dosage area product and amount of administered contrast medium (p > 0.05).
It can be stated that 3D-RDSA is a feasible method that facilitates the catheterization of the uterine artery even in patients with complex pelvic vessel anatomy, with the potential to reduce the radiation exposure and the amount of administered contrast medium in future embolization therapy of symptomatic uterine fibroids.
RöFo - Fortschritte auf dem Gebiet der R 07/2004; 176(7):1001-4. · 2.76 Impact Factor
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[show abstract]
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ABSTRACT: In patients with hepatocellular carcinoma (HCC) surgical resection so far offers potential cure. Due to the frequent association with liver cirrhosis less then 30% of patients with HCC can be resected. In unresectable cases, radiofrequency ablation (RFA) offers an effective treatment alternative. Substantial improvements in the development of powerful generators (up to 250 W) combined with expandable, closed or open-perfused needle electrodes, provide coagulation necroses up to 5 cm in diameter. Most recently primary technical success rates of 85 to 100% were reported. Following RFA of HCC's (diameter up to 2,8 cm) 1-, 2-, 3 and 5-year survival was reported to be 97, 89, 71 and 48%. Low complication rates of 0-12% and a mortality of 0-1% indicate the minimal-invasive character of RFA. Basic principles, technique, indications, contraindications and limitations of percutaneous RFA will be discussed together with a presentation of own cases and a review of literature.
Der Radiologe 05/2004; 44(4):330-8. · 0.61 Impact Factor
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ABSTRACT: We report on a 3-year experience using single-shot, ultrasonography-guided, percutaneous ethanol ablation (PEA) of hyperplastic parathyroid glands in chronic dialysis patients suffering from secondary or tertiary hyperparathyroidism.
Seventeen uraemic patients (mean age 52 +/- 14 years) with hypercalcaemia and elevated serum levels of parathyroid hormone were assessed for ethanol ablation. Ten patients did not fulfil the inclusion criteria and underwent surgical parathyroidectomy. Seven patients were treated using PEA.
All patients treated with PEA tolerated the procedure well, and no major complications were observed. Three out of seven patients underwent further ethanol ablation due to recurrent symptomatic hyperparathyroidism. Following the procedures, serum values of total calcium and parathyroid hormone remained within target range with concomitant medical therapy in all patients.
PEA performed as a single-shot therapy can be used as a minimally invasive and safe supplement to medical therapy in the treatment of secondary or tertiary hyperparathyroidism in selected patients. In case of recurrence, treatment can be repeated without any problems.
Ultraschall in der Medizin 05/2004; 25(2):131-6. · 2.40 Impact Factor
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[show abstract]
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ABSTRACT: Bei Patienten mit hepatozellulrem Karzinom (HCC) ist die chirurgische Resektion die einzige lebensverlngernde Therapie und damit Methode der Wahl. Aus operationstechnischen Grnden und wegen der oft ausgeprgten Leberzirrhose sind weniger als 30% der Patienten resektabel. Als vielversprechende Alternative zur Resektion wird die Radiofrequenzablation (RFA) zunehmend zur Behandlung nichtresektabler Lebertumoren eingesetzt.Entscheidende Fortschritte bei der Entwicklung leistungsfhiger Generatoren (bis 250W) in Kombination mit expandierbaren oder gekhlten Nadelelektroden ermglichen In-vivo-Ablationsareale bis ber 5cm.Neuesten Daten zu Folge liegt die primre technische Erfolgsrate der RFA von HCCs zwischen 85 und 100%. Nach RFA von HCCs (Durchmesser bis 2,8cm) betrgt die berlebenswahrscheinlichkeit nach 1, 2, 3, und 5Jahren 97, 89, 71 und 48%. Komplikationsraten von 0–12% und eine Mortalitt von 0–1% belegen den minimal-invasiven Charakter dieser Methode. Die grundlegenden Prinzipien der RFA, Indikationen, Kontraindikationen und Limitationen werden anhand eigener Flle und der aktuellen Literatur dargestellt.In patients with hepatocellular carcinoma (HCC) surgical resection so far offers potential cure. Due to the frequent association with liver cirrhosis less then 30% of patients with HCC can be resected. In unresectable cases, radiofrequency ablation (RFA) offers an effective treatment alternative. Substantial improvements in the development of powerful generators (up to 250W) combined with expandable, closed or open-perfused needle electrodes, provide coagulation necroses up to 5cm in diameter. Most recently primary technical success rates of 85 to 100% were reported. Following RFA of HCCs (diameter up to 2,8cm) 1-, 2-, 3 and 5-year survival was reported to be 97, 89, 71 and 48%. Low complication rates of 0–12% and a mortality of 0–1% indicate the minimal-invasive character of RFA.Basic principles, technique, indications, contraindications and limitations of percutaneous RFA will be discussed together with a presentation of own cases and a review of literature.
Der Radiologe 03/2004; 44(4):330-338. · 0.61 Impact Factor
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[show abstract]
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ABSTRACT: Vertebroplasty is a radiological intervention for the augmentation of bone lesions with bone cement. Main indications are the treatment of osteoporotic vertebral body fractures, however also the treatment of tumorous lesions becomes more and more established. The indication for vertebroplasty of tumorous lesions is therapy-refractory pain in symptomatic hemangiomas, metastases and myelomas. By minimal invasive therapy stabilization of vertebral bodies and pain reduction may be achieved.
Der Radiologe 10/2003; 43(9):723-8. · 0.61 Impact Factor
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[show abstract]
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ABSTRACT: Die perkutane Vertebroplastie (PV) stellt ein interventionell-radiologisches Verfahren zur Augmentation von Knochenlsionen mittels Knochenzement dar. Whrend die Hauptindikation in der Behandlung osteoporotischer Wirbelkrperfrakturen zu sehen ist, gewinnt auch die Behandlung tumorser Knochenlsionen zunehmend an Bedeutung. Indikationen sind therapieresistente schmerzhafte Wirbelkrperlsionen bei symptomatischen Hmangiomen, Metastasen und Myelomen. Durch die minimal-invasive Behandlungsmethode knnen eine Stabilisierung des Wirbelkrpers und eine deutliche Schmerzreduktion erreicht werden.Vertebroplasty is a radiological intervention for the augmentation of bone lesions with bone cement. Main indications are the treatment of osteoporotic vertebral body fractures, however also the treatment of tumorous lesions becomes more and more established. The indication for vertebroplasty of tumorous lesions is therapyrefractory pain in symptomatic hemangiomas, metastases and myelomas. By minimal invasive therapy stabilization of vertebral bodies and pain reduction may be achieved.
Der Radiologe 08/2003; 43(9):723-728. · 0.61 Impact Factor
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[show abstract]
[hide abstract]
ABSTRACT: To test the feasibility of noninvasive magnetic resonance (MR) imaging-guided focused ultrasound surgery (FUS) of benign fibroadenomas in the breast.
Eleven fibroadenomas in nine patients under local anesthesia were treated with MR imaging-guided FUS. Based on a T2-weighted definition of target volumes, sequential sonications were delivered to treat the entire target. Temperature-sensitive phase-difference-based MR imaging was performed during each sonication to monitor focus localization and tissue temperature changes. After the procedure, T2-weighted and contrast material-enhanced T1-weighted MR imaging were performed to evaluate immediate and long-term effects.
Thermal imaging sequences were improved over the treatment period, with 82% (279 of 342) of the hot spots visible in the last seven treatments. The MR imager was used to measure temperature elevation (12.8 degrees -49.9 degrees C) from these treatments. Eight of the 11 lesions treated demonstrated complete or partial lack of contrast material uptake on posttherapy T1-weighted images. Three lesions showed no marked decrease of contrast material uptake. This lack of effective treatment was most likely due to a lower acoustic power and/or patient movement that caused misregistration. No adverse effects were detected, except for one case of transient edema in the pectoralis muscle 2 days after therapy.
MR imaging-guided FUS can be performed to noninvasively coagulate benign breast fibroadenomas.
Radiology 05/2001; 219(1):176-85. · 5.73 Impact Factor
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ABSTRACT: In this study a computer aided navigation technique for accurate positioning of oral implants was assessed. An optical tracking system with specially designed tools for monitoring the position of surgical instruments relative to the patient was used to register 5 partially or completely edentulous jaw models. Besides the accuracy of the tracking system, the precision of localizing a specific position on 3-dimensional preoperative imagery is governed by the registration algorithm which conveys the coordinate system of the preoperative computed tomography (CT) scan to the actual patient position. Two different point-to-point registration algorithms were compared for their suitability for this application. The accuracy was determined separately for the localization error of the position measurement hardware (fiducial localization error-FLE) and the error as reported by the registration algorithm (fiducial registration error-FRE). The overall error of the navigation procedure was determined as the localization error of additional landmarks (steel spheres, 0.5 mm diameter) after registration (target registration error-TRE). Images of the jaw models were obtained using a high resolution CT scan (1.5 mm slice thickness, 1 mm table feed, incremental scanning, 120 kV, 150 mAs, 512 x 512 matrix, FOV 120 mm). The accuracy of the position measurement probes was 0.69 +/- 0.15 mm (FLE). Using 3 implanted fiducial markers, FRE was 0.71 +/- 0.12 mm on average and 1.00 +/- 0.13 mm maximum. TRE was found to be 1.23 +/- 0.28 mm average and 1.87 +/- 0.47 mm maximum. Increasing the number of fiducial markers to a total of 5 did not significantly improve precision. Furthermore it was found that a registration algorithm based on solving an eigenvalue problem is the superior approach for point-to-point matching in terms of mathematical stability. The experimental results indicate that positioning accuracy of oral implants may benefit from computer aided intraoperative navigation. The accuracy achieved compares well to the resolution of the CT scan used. Further development of point-to-point/point-to-surface registration methods and tracking hardware has the potential to improve the precision of the method even further. Our system has potential to reduce the intraoperative risk of causing damage to critical anatomic structures, to minimize the efforts in prosthetic modelling, and to simplify the task of transferring preoperative planning data precisely to the operating room in general.
Clinical Oral Implants Research 03/2001; 12(1):69-78. · 2.51 Impact Factor
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J Kettenbach,
B Pokrajac,
S Schamp,
C Fellner,
R Schmid,
B Gustorff,
J Berger,
M Grgurin,
K Peer,
U Wolff,
W Seitz,
R Pötter,
J Lammer
[show abstract]
[hide abstract]
ABSTRACT: To evaluate the feasibility and efficacy of MR-guided interstitial brachytherapy of non-resectable liver metastasis.
Liver metastases (0.8-5.2 cm in diameter) were treated during a prospective phase I/II study using an open 0.2 Tesla MR system (Magnetom Open Viva, Siemens, Erlangen). MR-compatible brachytherapy applicators were placed percutaneously under MR-guidance in an open 0.2 Tesla MR system (Magnetom Open Viva, Siemens, Erlangen) using fast T1-weighted sequences. Pretreatment and follow-up studies were performed using a 1.5 Tesla MR system.
Preliminary results of an unpublished prospective study are discussed exemplary on 2 selected patients. The median procedure time was 4.9 h. No major complications were observed and late effects were acceptable. In large symptomatic metastases only a temporary relief of pain was achieved. In smaller metastases (DM 3 cm) a tumor control was observed.
MR-guided brachytherapy is feasible and has the potential to ablate liver metastases with diameter of less than 3 cm. Further developments are necessary.
Der Radiologe 02/2001; 41(1):56-63. · 0.61 Impact Factor
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J Kettenbach,
D F Kacher,
S K Koskinen,
S G Silverman,
A Nabavi,
D Gering,
C M Tempany,
R B Schwartz,
R Kikinis,
P M Black,
F A Jolesz
[show abstract]
[hide abstract]
ABSTRACT: The goal of the Image Guided Therapy Program, as the name implies, is to develop the use of imaging to guide minimally invasive therapy. The program combines interventional and intraoperative magnetic resonance imaging (MRI) with high-performance computing and novel therapeutic devices. In clinical practice the multidisciplinary program provides for the investigation of a wide range of interventional and surgical procedures. The Signa SP 0.5 T superconducting MRI system (GE Medical Systems, Milwaukee, WI) has a 56-cm-wide vertical gap, allowing access to the patient and permitting the execution of interactive MRI-guided procedures. This system is integrated with an optical tracking system and utilizes flexible surface coils and MRI-compatible displays to facilitate procedures. Images are obtained with routine pulse sequences. Nearly real-time imaging, with fast gradient-recalled echo sequences, may be acquired at a rate of one image every 1.5 s with interactive image plane selection. Since 1994, more than 800 of these procedures, including various percutaneous procedures and open surgeries, have been successfully performed at Brigham and Women's Hospital (Boston, MA).
Annual Review of Biomedical Engineering 02/2000; 2:661-90. · 12.21 Impact Factor
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[show abstract]
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ABSTRACT: The aim of this study was to evaluate whether the use of a digital continuous speech recognition (CSR) in the field of radiology could lead to relevant time savings in generating a report. A CSR system (SP6000, Philips, Eindhoven, The Netherlands) for German was used to transform fluently spoken sentences into text. Two radiologists dictated a total of 450 reports on five radiological topics. Two typists edited those reports by means of conventional typing using a text editor (WinWord 6.0, Microsoft, Redmond, Wash.) installed on an IBM-compatible personal computer (PC). The same reports were generated using the CSR system and the performance of both systems was then evaluated by comparing the time needed to generate the reports and the error rates of both systems. In addition, the error rate of the CSR system and the time needed to create the reports was evaluated. The mean error rate for the CSR system was 5.5%, and the mean error rate for conventional typing was 0.4%. Reports edited with the CSR, on average, were generated 19% faster compared with the conventional text-editing method. However, the amount of error rates and time savings were different and depended on topics, speakers, and typists. Using CSR the maximum time saving achieved was 28% for the topic sonography. The CSR system was never slower, under any circumstances, than conventional typing on a PC. When compared with a conventional manual typing method, the CSR system proved to be useful in a clinical setting and saved time in generating radiological reports. The amount of time saved, however, greatly depended on the performance of the typist, the speaker, and on stored vocabulary provided by the CSR system.
European Radiology 02/2000; 10(12):1976-82. · 3.22 Impact Factor
