scholarly journals Diagnostic Performance of a Lower‐dose Contrast‐Enhanced 4D Dynamic MR Angiography of the Lower Extremities at 3 T Using Multisegmental Time‐Resolved Maximum Intensity Projections

2021 ◽  
Author(s):  
Paul Raczeck ◽  
Peter Fries ◽  
Alexander Massmann ◽  
Peter Minko ◽  
Felix Frenzel ◽  
...  
Keyword(s):  
Mr Angiography ◽  
Diagnostic Performance ◽  
Lower Extremities ◽  
Maximum Intensity ◽  
Time Resolved ◽  
Contrast Enhanced ◽  
Maximum Intensity Projections ◽  
Dynamic Mr

Time-resolved, contrast-enhanced 3D MR angiography in the subclavian steal effect

VASA ◽  
2010 ◽  
Vol 39 (1) ◽  
pp. 85-93 ◽  
Author(s):  
Schubert
Keyword(s):  
Mr Angiography ◽  
Time Resolved ◽  
Time To Peak ◽  
Vertebral Arteries ◽  
Subclavian Steal ◽  
Cerebrovascular Events ◽  
Graphic Analysis ◽  
Contrast Enhanced ◽  
Hemodynamic Information ◽  
Supraaortic Vessels

The subclavian steal effect indicates atherosclerotic disease of the supraaortic vessels but rarely causes cerebrovascular events in itself. Noninvasive imaging providing detailed anatomic as well as hemodynamic information would therefore be desirable. From a group of 25 consecutive patients referred for MR angiography, four with absent or highly attenuated signal in one of the vertebral arteries on 3D multislab time-of-flight MR angiography were selected to undergo 3D time-resolved contrast-enhanced MR angiography. The time-resolved 3D contrast series (source images and MIPs) were evaluated visually and by graphic analysis of time-intensity curves derived from the respective V1 and V3 segments of both vertebral arteries on the source images. In two cases with high-grade proximal left subclavian stenosis, time-resolved 3D ce-MRA was able to visualise retrograde contrast filling of the left VA. There was a marked delay in time-to-peak between the left and right V1 segments in one case and a shallower slope of enhancement in another. In the other two cases, there was complete or collateralised segmental occlusion of the VAs.

Coarctation of the abdominal aorta: Demonstration of a rare anomaly using contrast-enhanced MR-angiography

VASA ◽  
2009 ◽  
Vol 38 (1) ◽  
pp. 66-71 ◽  
Author(s):  
Schubert
Keyword(s):  
Abdominal Aorta ◽  
Mr Angiography ◽  
Parallel Imaging ◽  
Left Renal Vein ◽  
Systemic Hypertension ◽  
Contrast Enhanced ◽  
Younger Age ◽  
Maximum Intensity Projections ◽  
Collateral Vessels ◽  
First Time

We describe a case of aortic coarctation at the level of the infrarenal abdominal aorta which is encountered in less than six individuals in one million. In contrast to aortic narrowing above or including the renal arteries, this seems to be a relatively benign anomaly without systemic hypertension or impaired renal function. For the first time in this type of anomaly, contrast-enhanced MR angiography (ce-MRA) on a multi-receiver channel MR system, with an 8-channel phased array coil and parallel imaging was used. Ce-MRA displayed a tortuous, narrowed aortic segment that was found to be associated with mesenteric artery stenosis and compression of the orthotopic left renal vein, also known as the nutcracker phenomenon. All major aortic branches could be depicted using 3D surface-shaded displays and subvolume maximum intensity projections (MIPs). Collateral vessels of the abdominal wall were identified using whole-volume MIPs. Since the majority of aortic malformations are diagnosed at a younger age, and many suffer from renal insufficiency, we conclude that ce-MRA will eventually place conventional DSA as the modality of choice in malformations of the abdominal aorta.

scholarly journals Detection and Diagnosis of Breast Cancer Using Artificial Intelligence Based Assessment of Maximum Intensity Projection Dynamic Contrast-Enhanced Magnetic Resonance Images

Diagnostics ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 330
Author(s):  
Mio Adachi ◽  
Tomoyuki Fujioka ◽  
Mio Mori ◽  
Kazunori Kubota ◽  
Yuka Kikuchi ◽  
...  
Keyword(s):  
Artificial Intelligence ◽  
Magnetic Resonance ◽  
Diagnostic Performance ◽  
Maximum Intensity Projection ◽  
Breast Mri ◽  
Magnetic Resonance Images ◽  
Maximum Intensity ◽  
Validation Data ◽  
Dynamic Contrast Enhanced ◽  
Contrast Enhanced

We aimed to evaluate an artificial intelligence (AI) system that can detect and diagnose lesions of maximum intensity projection (MIP) in dynamic contrast-enhanced (DCE) breast magnetic resonance imaging (MRI). We retrospectively gathered MIPs of DCE breast MRI for training and validation data from 30 and 7 normal individuals, 49 and 20 benign cases, and 135 and 45 malignant cases, respectively. Breast lesions were indicated with a bounding box and labeled as benign or malignant by a radiologist, while the AI system was trained to detect and calculate possibilities of malignancy using RetinaNet. The AI system was analyzed using test sets of 13 normal, 20 benign, and 52 malignant cases. Four human readers also scored these test data with and without the assistance of the AI system for the possibility of a malignancy in each breast. Sensitivity, specificity, and area under the receiver operating characteristic curve (AUC) were 0.926, 0.828, and 0.925 for the AI system; 0.847, 0.841, and 0.884 for human readers without AI; and 0.889, 0.823, and 0.899 for human readers with AI using a cutoff value of 2%, respectively. The AI system showed better diagnostic performance compared to the human readers (p = 0.002), and because of the increased performance of human readers with the assistance of the AI system, the AUC of human readers was significantly higher with than without the AI system (p = 0.039). Our AI system showed a high performance ability in detecting and diagnosing lesions in MIPs of DCE breast MRI and increased the diagnostic performance of human readers.

Dynamic MR venography: An intrinsic benefit of time-resolved MR angiography

2006 ◽  
Vol 24 (4) ◽  
pp. 922-927 ◽  
Author(s):  
Jiang Du ◽  
Frank J. Thornton ◽  
Charles A. Mistretta ◽  
Thomas M. Grist
Keyword(s):  
Mr Angiography ◽  
Mr Venography ◽  
Time Resolved ◽  
Dynamic Mr

scholarly journals Contrast-Enhanced Magnetic Resonance Angiography Using a Novel Elastin-Specific Molecular Probe in an Experimental Animal Model

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Carolin Reimann ◽  
Julia Brangsch ◽  
Jan Ole Kaufmann ◽  
Lisa C. Adams ◽  
David C. Onthank ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Image Quality ◽  
Magnetic Resonance Angiography ◽  
Contrast Agent ◽  
Mr Angiography ◽  
Molecular Probe ◽  
Time Resolved ◽  
Clinical Dose ◽  
Contrast Enhanced ◽  
First Pass

Objectives. The aim of this study was to test the potential of a new elastin-specific molecular agent for the performance of contrast-enhanced first-pass and 3D magnetic resonance angiography (MRA), compared to a clinically used extravascular contrast agent (gadobutrol) and based on clinical MR sequences. Materials and Methods. Eight C57BL/6J mice (BL6, male, aged 10 weeks) underwent a contrast-enhanced first-pass and 3D MR angiography (MRA) of the aorta and its main branches. All examinations were on a clinical 3 Tesla MR system (Siemens Healthcare, Erlangen, Germany). The clinical dose of 0.1 mmol/kg was administered in both probes. First, a time-resolved MRA (TWIST) was acquired during the first-pass to assess the arrival and washout of the contrast agent bolus. Subsequently, a high-resolution 3D MRA sequence (3D T1 FLASH) was acquired. Signal-to-noise ratios (SNRs) and contrast-to-noise ratios (CNRs) were calculated for all sequences. Results. The elastin-specific MR probe and the extravascular imaging agent (gadobutrol) enable high-quality MR angiograms in all animals. During the first-pass, the probes demonstrated a comparable peak enhancement (300.6 ± 32.9 vs. 288.5 ± 33.1, p>0.05). Following the bolus phase, both agents showed a comparable intravascular enhancement (SNR: 106.7 ± 11 vs. 102.3 ± 5.3; CNR 64.5 ± 7.4 vs. 61.1 ± 7.2, p>0.05). Both agents resulted in a high image quality with no statistical difference (p>0.05). Conclusion. The novel elastin-specific molecular probe enables the performance of first-pass and late 3D MR angiography with an intravascular contrast enhancement and image quality comparable to a clinically used extravascular contrast agent.

scholarly journals Time-resolved, high-resolution contrast-enhanced MR angiography of dialysis shunts using the CENTRA keyhole technique with parallel imaging

2007 ◽  
Vol 25 (4) ◽  
pp. 832-840 ◽  
Author(s):  
Katja A. Mende ◽  
Johannes M. Froehlich ◽  
Constantin von Weymarn ◽  
Romhild Hoogeveen ◽  
Thomas Kistler ◽  
...  
Keyword(s):  
High Resolution ◽  
Mr Angiography ◽  
Parallel Imaging ◽  
Time Resolved ◽  
Contrast Enhanced

Abstract WP120: Measuring Carotid Stenosis With a Novel Non-contrast Enhanced MR Angiography Technique (SNAP): Comparison With Contrast-enhanced MR Angiography

Stroke ◽  
2016 ◽  
Vol 47 (suppl_1) ◽  
Author(s):  
Hongge Shu ◽  
Jie Sun ◽  
Niranjan Balu ◽  
Haining Liu ◽  
Daniel S Hippe ◽  
...  
Keyword(s):  
Carotid Stenosis ◽  
Mr Angiography ◽  
Carotid Arteries ◽  
Weighted Kappa ◽  
Intraplaque Hemorrhage ◽  
Gadolinium Contrast ◽  
Isotropic Resolution ◽  
Contrast Enhanced ◽  
Hemorrhage Risk ◽  
Maximum Intensity Projections

Introduction: Contrast-enhanced MR angiography (CE-MRA) provides highly accurate measurement of carotid stenosis. But non-contrast techniques are desired as contrast agents may lead to anaphylaxis or nephrogenic system fibrosis. Recently, an inversion-recovery gradient echo sequence with phase-sensitive reconstruction was developed for assessment of lumen and intraplaque hemorrhage in one sequence - Simultaneous Noncontrast Angiography and intraPlaque hemorrhage (SNAP). Hypothesis: We tested the hypothesis that SNAP provides an accurate and reproducible assessment of carotid stenosis compared to CE-MRA. Methods: Fifty-eight subjects with 16-79% stenosis on ultrasound were scanned using a large-coverage (16 cm), isotropic-resolution (0.8 mm) SNAP sequence. Minimum intensity projections were generated at ten degrees increments to get 3D views of carotid arteries. Carotid stenosis was measured bilaterally according to the NASCET criteria by independent readers to estimate inter-reader reproducibility. To assess agreement between SNAP and CE-MRA, 24 subjects also underwent CE-MRA with same resolution (0.8 mm isotropic) after injection of gadolinium contrast (Magnevist). Maximum intensity projections were generated for CE-MRA and analyzed while blinded to SNAP data. Results: Of 116 carotid arteries imaged by SNAP, 10 (8.6%) were excluded by at least one reader due to poor image quality or insufficient coverage. Inter-reader reproducibility was high, yielding an intra-class correlation coefficient (ICC) of 0.95 (95% CI: 0.93, 0.96). When stenosis measurements were categorized as no/mild (0-29%), moderate (30-69%) and severe (70-99%), weighted kappa was 0.77 (95% CI: 0.66, 0.88). In the 48 arteries with CE-MRA images, agreement between SNAP and CE-MRA was excellent (ICC: 0.96, 95% CI: 0.92, 0.98; weighted kappa: 0.90, 95% CI: 0.79, 1.00). Conclusions: SNAP can be used to obtain accurate and reproducible measurement of extracranial carotid artery stenosis without gadolinium contrast. The ability of SNAP to assess both traditional (stenosis) and emerging (intraplaque hemorrhage) risk factors may promote its use in clinical workup of carotid stenosis.

scholarly journals Combining Time-resolved and Single-phase 3D Techniques in Contrast-enhanced Carotid MR Angiography

2002 ◽  
Vol 1 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Makoto SASAKI ◽  
Hirobumi OIKAWA ◽  
Kunihiro YOSHIOKA ◽  
Yoshiharu TAMAKAWA ◽  
Hiromu KONNO ◽  
...  
Keyword(s):  
Mr Angiography ◽  
Single Phase ◽  
Time Resolved ◽  
Contrast Enhanced
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