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J F Debatin

Publications and source records attributed to J F Debatin.

At least 73 records · Page 4Linked to original sources
PubMed2000

Colonic masses: detection with MR colonography.

PURPOSE: To assess magnetic resonance (MR) colonography as a method for detection of colorectal masses, with conventional colonoscopy as the reference standard. MATERIALS AND METHODS: MR colonography was performed in 132 patients referred for colonoscopy because of the possible presence of a mass. After rectal filling with a gadopentetate dimeglumine and water enema, T1-weighted three-dimensional gradient-echo MR studies were acquired with the patient in the prone and supine positions. Water-sensitive single-shot fast spin-echo MR images were also obtained. Surface-rendered virtual endoscopic endoluminal views, orthogonal sections in three planes, and water-sensitive MR images were interactively assessed for presence of colorectal masses by two radiologists. RESULTS: MR colonography was well tolerated without sedation or analgesia. MR image quality was sufficient for diagnosis in 127 (96%) patients. Most small (</=5-mm-diameter) masses were overlooked at MR colonography, but 19 of 31 6-10-mm lesions and 26 of 27 large (>10-mm) lesions were correctly identified. For these large masses, MR colonography had a sensitivity of 93%, specificity of 99%, positive predictive value of 92%, and negative predictive value of 98% for detection of masses. CONCLUSION: MR colonography is a promising modality for help in detecting colorectal mass lesions larger than 10 mm in diameter.

Administration, Rectal↗
PubMed2000

Pelvic and lower extremity arterial imaging: diagnostic performance of three-dimensional contrast-enhanced MR angiography.

OBJECTIVE: The diagnostic performance of a three-dimensional MR angiography-based strategy was assessed with regard to its ability to characterize the arterial vasculature from the aortic bifurcation to the lower extremity runoff vessels. A single-injection, two-station protocol in combination with a lower-extremity vascular coil was used. SUBJECTS AND METHODS: Both conventional digital subtraction angiography and three-dimensional contrast-enhanced MR angiography with a dedicated peripheral vascular coil were performed in 61 patients with suspected peripheral vascular disease. In a prospective analysis, one reviewer evaluated the digital subtraction angiographic images and a second reviewer evaluated the MR angiographic images; both were unaware of the results of the other imaging technique. Each vascular segment (29 segments per patient) was evaluated for the presence of occlusive vessel disease. The following grading system was applied: 0, normal; 1, vessel irregularity with a luminal reduction of less than 10%; 2, mild stenosis (lumen reduction, 10-49%); 3, severe stenosis (lumen reduction, 50-99%); and 4, occlusion (lumen reduction, 100%). In 11 patients surgical graft patency was assessed. RESULTS: MR angiography provided an image quality comparable with that of digital subtraction angiography. Overall sensitivity and specificity for MR angiography were 92% and 96.6%, respectively, for the detection of hemodynamically significant disease and 92.3% and 99.4%, respectively, for the detection of occlusions. CONCLUSION: Two-station contrast-enhanced three-dimensional MR angiography with a dedicated lower-extremity vascular coil proved effective enough to consider it as a noninvasive alternative to digital subtraction angiography in the assessment of the pelvic and lower extremity arterial vasculature.

Adult↗
PubMed2000

Ultrafast MR imaging of the fetus.

OBJECTIVE: We examined the capability of ultrafast single-shot fast spin-echo imaging to assess different fetal organ systems compared with prenatal sonography, using autopsy or postpartum imaging as a standard of reference. SUBJECTS AND METHODS: Thirty women with complicated pregnancies (mean age of gestation, 190 +/- 54 days) underwent T2-weighted ultrafast MR imaging. MR images were analyzed with regard to diagnostic confidence in assessing abnormalities of fetal organ systems, and data were correlated with postpartum findings or necropsy. Results were compared with those of prenatal sonography. RESULTS: Using receiver operating characteristic curve analysis, diagnostic confidence of MR imaging was best for assessing the brain (area under the curve [Az] = 0.96) and spinal canal (Az = 1.0), uteroplacental unit (Az = 0.93), and lungs (Az = 0.91). Results for the heart (Az = 0.63) and extremities (Az = 0.77) were significantly lower than that of other organs (p < 0.001). Diagnostic accuracy increased with gestational age. No statistically significant difference between sonography and MR imaging was found for the detection of abnormality in any organ system. In three fetuses, MR imaging was superior to sonography in characterizing cerebral abnormalities. MR imaging was inferior to sonography in characterizing abnormalities of the heart and extremities. CONCLUSION: Our results indicate that ultrafast MR imaging can be used for in vivo fetal imaging, especially in assessing cerebral abnormalities. However, MR imaging should be restricted to situations in which sonographic findings are ambiguous or impaired.

Congenital Abnormalities↗
PubMed2000

Equilibrium-phase MR angiography of the aortoiliac and renal arteries using a blood pool contrast agent.

OBJECTIVE: The purpose of this study was to determine the diagnostic usefulness of a new blood pool contrast agent, NC100150, for assessing the aortoiliac and renal arteries. SUBJECTS AND METHODS: Twenty patients with hemodynamically significant stenosis (> or =50% of luminal diameter) of the iliac or renal arteries or an aortic aneurysm documented by digital subtraction angiography underwent MR angiography at 1.5 T after administration of NC100150. Three-dimensional MR angiographic data sets were collected ill the equilibrium phase. In a prospective analysis, each vascular segment (16 segments per arterial tree) was evaluated. RESULTS: All patients tolerated the NC100150 administration well. Mean contrast-to-noise ratios of the vascular data collected in the equilibrium phase of NC100150 was 3.3+/-15.9. Compared with digital subtraction angiography, the sensitivity and specificity of MR angiography for the renal arteries were 82% and 98%, respectively; for the common iliac arteries, 86% and 97%, respectively; for the external iliac arteries, 80% and 100%, respectively; and for the internal iliac arteries, 71% and 977, respectively. All 83 aneurysmal changes revealed by digital subtraction angiograpy of the aortoiliac arteries were well displayed on the MR angiographic data sets. CONCLUSION: Equilibrium-phase NC 00150-enhanced three-dimensional MR angiography shows high specificity when evaluating the abdominal and pelvic vascular systems, but the attendant venous overlap can limit the assessment of stenosis in renal and pelvic arterial segments.

Adult↗
PubMed1999

High-resolution intravascular magnetic resonance imaging: monitoring of plaque formation in heritable hyperlipidemic rabbits.

BACKGROUND: The individual makeup of atherosclerotic plaque has been identified as a dominant prognostic factor. With the use of an intravascular magnetic resonance (MR) catheter coil, we evaluated the effectiveness of high-resolution MR in the study of the development of atherosclerotic lesions in heritable hyperlipidemic rabbits. METHODS AND RESULTS: Sixteen hyperlipidemic rabbits were investigated at the ages of 6, 12, 24, and 36 months. The aorta was studied with digital subtraction angiography and high-resolution MR with the use of a surface coil and an intravascular coil that consisted of a single-loop copper wire integrated in a 5F balloon catheter. Images were correlated with histological sections regarding wall thickness, plaque area, and plaque components. Digital subtraction angiography revealed no abnormalities in the 6- and 12-month-old rabbits and only mild stenoses in the 24- and 36-month-old rabbits. High-resolution imaging with surface coils resulted in an in-plane resolution of 234x468 microm. Delineation of the vessel wall was not possible in younger rabbits and correlated only poorly with microscopic measurements in the 36-month-old rabbits. Intravascular images achieved an in-plane resolution of 117x156 microm. Increasing thickness of the aortic wall and plaque area was observed with increasing age. In the 24- and 36-month-old animals, calcification could be differentiated from fibrous and fatty tissue on the basis of the T2-fast spin echo images, as confirmed by histological correlation. CONCLUSIONS: Atherosclerotic evolution of hyperlipidemic rabbits can be monitored with high-resolution intravascular MR imaging. Image quality is sufficient to determine wall thickness and plaque area and to differentiate plaque components.

Animals↗
PubMed1999

[New perspectives in 3D MR colonography].

Filling the colon lumen with contrast allows for 3D-MR-colonography. The 3D data set can be postprocessed to multiplanar reconstruction, surface shaded displays as well as virtual colonoscopy. The latter facilitates the differentiation between haustra and polyps and enables detection of polyps down to 6 mm in size. Multiplanar reconstructions provide the assessment of the inner wall contour. The morphology of the colonic wall itself can be assessed on T1- or T2-weighted images. T1-weighted sequences performed before and after i.v. contrast administration and T2-weighted sequences depict pathologies based on their contrast uptake respectively on their tissue water content. This concept of colonic imaging practicable in less than 15 minutes is useful for the assessment of inflammatory disease, for polyp detection as well as for tumour staging.

Colonic Diseases↗
PubMed1999

Autoperfused balloon catheter for intravascular MR imaging.

An intravascular magnetic resonance (MR) imaging catheter for high-resolution imaging of vessel walls was developed. The catheter design is based on an autoperfusion balloon catheter that allows passive perfusion of blood during balloon inflation. The blood enters a central lumen through multiple sideholes of the catheter shaft proximal to the balloon. A remotely tuned, matched, and actively decoupled, expandable single-loop radiofrequency coil was mounted onto the balloon to receive intravascular MR signals. The autoperfusion rate through the catheter was determined experimentally relative to perfusion pressure. The catheter concept was evaluated in vitro on human femoral artery specimens and in vivo in the internal carotid artery of two pigs. The proposed catheter design allowed for maintained blood perfusion during the acquisition of high-resolution intravascular images. During perfusion, image quality remained unaffected by flow, motion, and pulsatility artifacts. The availability of an autoperfused intravascular catheter design can be considered an important step toward high-resolution atherosclerotic plaque imaging in critical vessels such as the carotid and coronary arteries.

Animals↗
PubMed1999

Contrast optimization for assessment of the colonic wall and lumen in MR colonography.

This report focuses on the optimization of magnetic resonance colonography for combined virtual endoluminal and T2-weighted wall analysis of the colon and demonstrates the potential of the single-shot fast spin-echo (SSFSE) sequence for identifying colorectal pathologies. A 45 degrees flip angle in the three-dimensional spoiled gradient-echo sequence and a TE of 60 msec in the SSFSE sequence in conjunction with a 10 mM gadolinium concentration in the enema results in maximal contrast for the delineation of the colonic lumen in T1-weighted imaging and the colonic wall in T2-weighted imaging. The SSFSE sequence reveals hyperintense signal for inflammatory disease and most polyps exceeding 10 mm in size. It supplements the virtual endoluminal assessment by aiding in the differentiation between mass lesions and fecal matter or residual air.

Colon↗
PubMed1999

Virtual MR arthroscopy: new insights into joint morphology.

Evaluation of the feasibility of virtual magnetic resonance (MR) arthroscopy was performed on 10 patients referred for MR arthrography of the shoulder, the elbow, or the knee. A fast spoiled contrast-enhanced three-dimensional gradient-echo sequence was combined with image postprocessing to render arthroscopic views. Virtual MR arthroscopy was successfully demonstrated in all 10 joints. Determination of added diagnostic benefit will require further study.

Adult↗
PubMed1999

Sequential fast 3D MRI following oral ingestion of Gd-DOTA: A new means to assess intestinal transit time.

A magnetic resonance image (MRI)-based method to determine the colonic transit time is described. It is based on the oral ingestion of a single dose of 4 ml Gd-DOTA following an overnight fast and the subsequent acquisition of fast three-dimensional (3D) gradient-echo sequences under apnea conditions. The technique was successfully evaluated in three healthy volunteers. Transit of the contrast agent through the small and large intestines was easily followed. Thus, MRI-based colonic transit time determinations are feasible.

Administration, Oral↗
PubMed1999

Single-loop coil concepts for intravascular magnetic resonance imaging.

Compared with other coil designs that have been investigated for intravascular use, the single-loop coil can be designed with a very small diameter for insertion into small vessels and with a longitudinal extent over several centimeters for multislice imaging. If it designed to be expandable inside the target vessel, then it combines these features with increased signal-to-noise ratio (SNR) and penetration depth. Expandable single-loop coils that are capable of meeting these requirements were developed and integrated into two different commercial catheter-based delivery systems: a self-expandable, single-loop made from NiTinol and a single-loop coil mounted on an inflatable balloon. The influence of a small-diameter coaxial cable for remote tuning and matching on the coil performance was investigated. Calculations showed the dependence of the signal on the separation between the conductors. The comparison of both catheter approaches in in vitro flow experiments and in an in vivo pig experiment revealed the influence of pulsatile flow on image quality during intravascular imaging with these designs.

Animals↗
PubMed1999

Vascular stents as RF antennas for intravascular MR guidance and imaging.

Stent deployment is used to improve the immediate and long-term results of vascular interventions in various vascular sites. X-ray angiography as an imaging modality is often limited in providing an accurate assessment with regard to vessel size, plaque calcification, or stent deployment. In this study, the potential of using the stent endoprothesis as a radiofrequency (RF) receive-only probe for MR guidance and lesion imaging was investigated. Three different principles were developed to visualize stents actively, the first employing the stent as a loop antenna, the second employing the stent in an electrical dipole configuration, and the third employing the stent in a hybrid configuration as a coaxial line antenna. The three configurations resulted in different signal characteristics. Based on two of these antenna configurations, stent deployment devices were built and evaluated in in vitro as well as in vivo sheep experiments. Active stent visualization allows real-time MR guidance through the vessel tree and monitoring of stent deployment. In addition, the stent antenna may become useful for high resolution imaging of the vessel wall. Magn Reson Med 42:738-745, 1999.

Animals↗
PubMed1999

In vitro image characteristics of an abdominal aortic stent graft: CTA versus 3D MRA.

Percutaneous stent-grafting is increasingly employed as a less invasive alternative to surgery for the treatment of infrarenal abdominal aortic aneurysms. It requires long-term imaging follow-up, to document the structural integrity of the device, to exclude perigraft channels and endograft leakages, as well as the shrinkage of the aneurysmal sac. The expectation of severe stent induced artifacts and safety concerns have prevented 3D MRA from being used. The purpose of this in vitro study was to investigate the imaging characteristics of a bifurcated stent graft with 3D MRA (3D Fourier transform fast spoiled GRE) at 1.5 T in comparison to those of CTA. Measurement of the stent wall thickness and luminal diameter were made on a agar gel embedded stent graft at five locations on both CTA and MRA images. The stent graft was depicted as a dark ring on MR images. Wall thickness measurements at the five locations of the stent graft overestimated the true stent thickness, while luminal diameters were slightly underestimated. Measurement differences between MR and CT were not statistically significant (P = 0.67; P = 0.85). Artifacts emanating from the platinum markers were considerably less severe on the MR-images. A wider area of signal loss was seen only at the insertion of the iliac stent leg into the aortic stent portion due to the overlap of two radio-opaque platinum markers. 3D MRA images should permit a comprehensive assessment of the arterial lumen, and of perivascular tissues.

Aortic Aneurysm, Abdominal↗
PubMed1999

3D MR gastrography: exoscopic and endoscopic analysis of the stomach.

The aim of this study was to evaluate the feasibility of MR gastrography, based on 3D MRI following the oral administration of Gd-DOTA-enriched blueberry juice, in order to depict alterations of the gastric wall. The stomachs of three volunteers and three patients were examined on a 1.5-T MR system. Following ingestion of 400 ml of blueberry juice spiked with 2 ml of Gd-DOTA, each subject underwent 3D MR imaging in three positions: 45 degrees left lateral decubitus, supine, and 45 degrees right lateral decubitus. In each position, a coronal 3D SPGR acquisition consisting of 60 continuous 2-mm slices was acquired over a 35-s breathhold (TR/TE = 4.0/1.8 ms, 40 degrees flip angle, 0.5 excitations, voxel size of 1.25 x 1.66 x 2.00 mm). Multiplanar reformats (MPR), maximum intensity projections (MIP), surface shaded displays (SSD), and virtual intraluminal endoscopic views (VIE) were calculated. Magnetic resonance gastroscopy was tolerated well by all subjects without adverse effects. Based on the 3D MRI data sets acquired in various patient positions, all regions of the stomach and the proximal duodenum were visualized to good advantage. Whereas MPR and MIP provided a morphologic overview, SSD and VIE images permitted analysis of the gastric mucosa. Normal mucosa could be differentiated from the course and irregular pattern characterizing carcinomatous infiltration. The 3D SPGR data sets acquired following ingestion of oral Gd-DOTA-spiked blueberry juice permits exoscopic and virtual endoscopic viewing of the stomach.

Adult↗
PubMed1999

Real-time MR-guided joint puncture and arthrography: preliminary results.

The purpose of this study was to evaluate interactive MR-guided joint puncture with intra-articular application of contrast agent. MR-guided arthrography of the shoulder joint was successfully performed in three patients using an interactive guidance system implemented in an open-configuration MR system. Visualization of the needle pathway and contrast inflow was comparable to that with conventional X-ray fluoroscopy. The position of the intra-articular needle tip was accurately confirmed and subsequent MR arthrography was diagnostic in all cases.

Adult↗
PubMed1999

Interactive MR-guided biopsies of maxillary and skull-base lesions in an open-MR system: first clinical results.

The purpose of this study was to explore the potential of interactive MR-guided biopsies in the maxillary and skull base region using a 0.5-T open-configuration scanner in patients with tumours affecting the maxilla or skull base. Ten patients with cystic or solid tumours affecting the maxillary and skull base regions underwent MR-guided biopsy in a superconducting, open 0.5-T MR system equipped with an optical frameless stereotaxic system. T2-weighted spin-echo images were acquired prior to and following biopsy, which was performed with 18- or 22-G needles using an enoral or percutaneous approach following infiltration of the skin, mucosa and periosteum with local anaesthetics. The position of the needle tip was continuously updated on fast T1-weighted gradient-recalled-echo images (TR 19 ms, TE 7.1 ms, flip angle 30 degrees, slice thickness 1 cm, field of view 24 x 24 cm) using the frameless stereotaxic system. In addition, the needle was identified based on the associated susceptibility artefact in all three planes. Once the target lesion had been reached, cytology material was aspirated. All ten patients tolerated the interactive MR-guided biopsies well without complications. Vital structures, including the brain, neurovascular bundles, vessels and eyes, were visualized on MR imaging and could be spared. There was no difference in the use of 18- or 22-G non-ferromagnetic needles concerning the susceptibility artefact. Sufficient material for cytological analysis was obtained in nine of ten cases. The mean biopsy time was 15 min. Interactive MR-guided biopsies of the head and neck in an open system are technically feasible and safe. Monitoring of the needle path in multiple planes permits the interactive adjustment of the needle course in near real time. Interactive MR-guided biopsies may well replace open surgical procedures in the maxillary region in selected patients.

Adult↗
PubMed1999

MRI of the small and large bowel.

Driven by the improvements in gradient technology, breathhold T1- and T2-weighted imaging of the abdominal structures has become possible. These techniques allow exploitation of the advantages inherent to the MR imaging experiment: unsurpassed soft tissue contrast and multiplanar imaging capabilities. Magnetic resonance imaging of the small and large bowel has thus moved from a hypothetical possibility to a practical reality. This manuscript describes some of the underlying fast imaging techniques for display of the small and large bowel. Furthermore, it discusses the plethora of available oral and rectal contrast agents. Finally, clinical indications for MR of the small and large bowel as well as the rectum are described in light of the available literature. Advantages and disadvantages relative to computed tomography and other imaging techniques are discussed.

Colon↗