scholarly journals Simplified Rapid Protocol for Assessing the Thoracic Aortic Dimensions and Pathology with Noncontrast MR Angiography

2019 ◽  
Vol 28 (02) ◽  
pp. 130-136 ◽  
Author(s):  
Megha Verma ◽  
Bharath Yarlagadda ◽  
Aditya Hendrani ◽  
Ambarish P. Bhat ◽  
Senthil Kumar
Keyword(s):  
Reference Points ◽  
Acquisition Time ◽  
Dark Blood ◽  
Contrast Enhanced ◽  
Aortic Pathology ◽  
Contrast Exposure ◽  
Clinically Significant ◽  
Absolute Measurements ◽  
Noncontrast Mra ◽  
Aortic Pathologies

AbstractContrast enhanced magnetic resonance angiography (CE-MRA) is limited by long acquisition time and contrast exposure in aortic emergencies. To compare the effcacy of dark blood (DB) and bright blood (BB) noncontrast sequences with the gold standard CE-MRA using a novel protocol for performing consistent thoracic aortic measurements and thoracic aortic pathologies identifications. A total of 66 patients with suspected or known thoracic aortic pathology who underwent CE-MRA underwent DB and BB imaging prior to CE-MRA for planning purposes. Aortic dimension was measured at 10 standard reference points in the ascending, arch, and descending aorta. Detection of aortic pathologies was recorded individually for each noncontrast sequence. When comparing the CE-MRA to the DB images and CE-MRA to the BB images, a majority of the measurement differences were less than or equal to 2 mm or resulted in no change of diagnostic class (95% for CE-MRA vs. DB and 96% for CE-MRA vs. BB). Of the patients who had major changes in diagnostic class (e.g., changes in two or three classes), the absolute measurements were not clinically significant in any given patient to warrant a change in management. Individually, the DB and BB sequences allowed for accurate recognition of all 47 aortic pathologies. DB and BB sequences produced comparable and consistent measurements of the thoracic aorta when compared with CE-MRA. In a situation where CE-MRA is not readily available or contraindicated, noncontrast MRA using our protocol is a reliable alternative to CE-MRA for assessment of aortic pathologies.

scholarly journals Extended perfusion protocol for MS lesion quantification

Open Medicine ◽  
2020 ◽  
Vol 15 (1) ◽  
pp. 520-530
Author(s):  
Eleftherios Kontopodis ◽  
Kostas Marias ◽  
Georgios C. Manikis ◽  
Katerina Nikiforaki ◽  
Maria Venianaki ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Magnetic Resonance ◽  
Goodness Of Fit ◽  
Accurate Determination ◽  
Acquisition Time ◽  
Minimal Extension ◽  
Dce Mri ◽  
Contrast Enhanced ◽  
Demyelinating Lesions ◽  
Mri Protocol

AbstractThis study aims to examine a time-extended dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) protocol and report a comparative study with three different pharmacokinetic (PK) models, for accurate determination of subtle blood–brain barrier (BBB) disruption in patients with multiple sclerosis (MS). This time-extended DCE-MRI perfusion protocol, called Snaps, was applied on 24 active demyelinating lesions of 12 MS patients. Statistical analysis was performed for both protocols through three different PK models. The Snaps protocol achieved triple the window time of perfusion observation by extending the magnetic resonance acquisition time by less than 2 min on average for all patients. In addition, the statistical analysis in terms of adj-R2 goodness of fit demonstrated that the Snaps protocol outperformed the conventional DCE-MRI protocol by detecting 49% more pixels on average. The exclusive pixels identified from the Snaps protocol lie in the low ktrans range, potentially reflecting areas with subtle BBB disruption. Finally, the extended Tofts model was found to have the highest fitting accuracy for both analyzed protocols. The previously proposed time-extended DCE protocol, called Snaps, provides additional temporal perfusion information at the expense of a minimal extension of the conventional DCE acquisition time.

scholarly journals Twofold improved tumor-to-brain contrast using a novel T1 relaxation-enhanced steady-state (T1RESS) MRI technique

2020 ◽  
Vol 6 (44) ◽  
pp. eabd1635
Author(s):  
R. Edelman ◽  
N. Leloudas ◽  
J. Pang ◽  
J. Bailes ◽  
R. Merrell ◽  
...  
Keyword(s):  
Steady State ◽  
Cancer Detection ◽  
Pulse Sequence ◽  
Signal To Noise Ratio ◽  
Cancer Imaging ◽  
Dark Blood ◽  
T1 Relaxation ◽  
Contrast Enhanced ◽  
Magnetic Resonance Imaging Mri ◽  
Standard Techniques

A technique that provides more accurate cancer detection would be of great value. Toward this end, we developed T1 relaxation-enhanced steady-state (T1RESS), a novel magnetic resonance imaging (MRI) pulse sequence that enables the flexible modulation of T1 weighting and provides the unique feature that intravascular signals can be toggled on and off in contrast-enhanced scans. T1RESS makes it possible to effectively use an MRI technique with improved signal-to-noise ratio efficiency for cancer imaging. In a proof-of-concept study, “dark blood” unbalanced T1RESS provided a twofold improvement in tumor-to-brain contrast compared with standard techniques, whereas balanced T1RESS greatly enhanced vascular detail. In conclusion, T1RESS represents a new MRI technique with substantial potential value for cancer imaging, along with a broad range of other clinical applications.

scholarly journals Automated Identification of Cephalometric Landmarks: Part 2- Might It Be Better Than human?

2019 ◽  
Vol 90 (1) ◽  
pp. 69-76 ◽  
Author(s):  
Hye-Won Hwang ◽  
Ji-Hoon Park ◽  
Jun-Ho Moon ◽  
Youngsung Yu ◽  
Hansuk Kim ◽  
...  
Keyword(s):  
Reference Points ◽  
Identification System ◽  
Learning Method ◽  
Detection Error ◽  
Hard Tissue ◽  
Automated Identification ◽  
Viable Option ◽  
The Mean ◽  
Clinically Significant ◽  
Better Than

ABSTRACT Objectives To compare detection patterns of 80 cephalometric landmarks identified by an automated identification system (AI) based on a recently proposed deep-learning method, the You-Only-Look-Once version 3 (YOLOv3), with those identified by human examiners. Materials and Methods The YOLOv3 algorithm was implemented with custom modifications and trained on 1028 cephalograms. A total of 80 landmarks comprising two vertical reference points and 46 hard tissue and 32 soft tissue landmarks were identified. On the 283 test images, the same 80 landmarks were identified by AI and human examiners twice. Statistical analyses were conducted to detect whether any significant differences between AI and human examiners existed. Influence of image factors on those differences was also investigated. Results Upon repeated trials, AI always detected identical positions on each landmark, while the human intraexaminer variability of repeated manual detections demonstrated a detection error of 0.97 ± 1.03 mm. The mean detection error between AI and human was 1.46 ± 2.97 mm. The mean difference between human examiners was 1.50 ± 1.48 mm. In general, comparisons in the detection errors between AI and human examiners were less than 0.9 mm, which did not seem to be clinically significant. Conclusions AI showed as accurate an identification of cephalometric landmarks as did human examiners. AI might be a viable option for repeatedly identifying multiple cephalometric landmarks.

scholarly journals Multimodality Fusion with MRI, CT, and Ultrasound Contrast for Ablation of Renal Cell Carcinoma

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Hayet Amalou ◽  
Bradford J. Wood
Keyword(s):  
Renal Tumor ◽  
Intraoperative Imaging ◽  
Kidney Tumor ◽  
Fusion Technology ◽  
Image Guided ◽  
Iodinated Contrast ◽  
Contrast Enhanced ◽  
Combined Use ◽  
Contrast Exposure ◽  
Different Parts

Fusion technology with electromagnetic (EM) tracking enables navigation with multimodality feedback that lets the operator use different modalities during different parts of the image-guided procedure. This may be particularly helpful in patients with renal insufficiency undergoing kidney tumor ablation, in whom there is a desire to minimize or avoid nephrotoxic iodinated contrast exposure. EM tracking software merges and fuses different imaging modalities such as MRI, CT, and ultrasound and can also display the position of needles in real time in relation to preprocedure imaging, which may better define tumor targets than available intraoperative imaging. EM tracking was successfully used to ablate a poorly visualized renal tumor, through the combined use of CT, gadolinium-enhanced MR, and contrast-enhanced US imaging to localize the tumor.

scholarly journals Sparse 3D contrast-enhanced whole-heart imaging for coronary artery evaluation

Herz ◽  
2022 ◽  
Author(s):  
Uzair Ansari ◽  
Sonja Janssen ◽  
Stefan Baumann ◽  
Martin Borggrefe ◽  
Stephan Waldeck ◽  
...  
Keyword(s):  
Coronary Artery ◽  
Image Quality ◽  
Cardiac Computed Tomography ◽  
Acquisition Time ◽  
Cohen’S Kappa ◽  
Cohen's Kappa ◽  
Contrast Enhanced ◽  
Significant Difference ◽  
Whole Heart

Abstract Background We investigated the feasibility of evaluating coronary arteries with a contrast-enhanced (CE) self-navigated sparse isotropic 3D whole heart T1-weighted magnetic resonance imaging (MRI) study sequence. Methods A total of 22 consecutive patients underwent coronary angiography and/or cardiac computed tomography (CT) including cardiac MRI. The image quality was evaluated on a 3-point Likert scale. Inter-reader variability for image quality was analyzed with Cohen’s kappa for the main coronary segments (left circumflex [LCX], left anterior descending [LAD], right coronary artery [RCA]) and the left main trunk (LMT). Results Inter-reader agreement for image quality of the coronary tree ranged from substantial to perfect, with a Cohen’s kappa of 0.722 (RCAmid) to 1 (LCXprox). The LMT had the best image quality. Image quality of the proximal vessel segments differed significantly from the mid- and distal segments (RCAprox vs. RCAdist, p < 0.05). The LCX segments showed no significant difference in image quality along the vessel length (LCXprox vs. LCXdist, p = n.s.). The mean acquisition time for the study sequence was 553 s (±46 s). Conclusion Coronary imaging with a sparse 3D whole-heart sequence is feasible in a reasonable amount of time producing good-quality imaging. Image quality was poorer in distal coronary segments and along the entire course of the LCX.

scholarly journals Evaluation of chronic headache by computed tomography: a retrospective study

2012 ◽  
Vol 1 (2) ◽  
pp. 64-71 ◽  
Author(s):  
Anish Subedee
Keyword(s):  
Computed Tomography ◽  
Chronic Headache ◽  
Patient Management ◽  
Alter Patient ◽  
Contrast Enhanced Ct ◽  
Contrast Enhanced ◽  
Enhanced Ct ◽  
Minor Abnormality ◽  
The Difference ◽  
Clinically Significant

Objective: To find out the proportion of intracranial abnormalities in patients with chronic headache without neurologic abnormality with the use of computed tomography (CT) and to compare the results with similar studies done previously. Materials and methods: CT images of 56 patients with chronic/recurrent headache and normal neurological findings were reviewed retrospectively. In 38 of 56 patients, both plain and contrast enhanced CT were done. Patients were divided into three groups according to the CT findings: those with no abnormality, those with minor abnormality (that did not alter patient management) and those with clinically significant abnormality. Proportion of patients in each group was found out and results were compared with previous studies with similar study design. Z test was used to evaluate whether the difference in proportions of patients in our study and previous study was statistically significant or not. Results: Of the 56 patients, 50 had normal CT (89.28 %), four had minor abnormality (7.14%) that did not alter patient management and two had significant lesions (3.57%). Contrast enhanced CT did not improve lesion detection. The minor findings detected were sub-ependymal calcifications of Tuberous sclerosis, calcified neurocysticercosis and old lacunar infarctions in external capsule. Clinically significant lesions detected were small ring enhancing lesion (neurocysticercosis or tuberculoma) and pineal cyst. Results of this study were compared with previous study with similar study design. The Z test showed that the difference in proportions in these studies was not statistically significant (p =0.0708 for minor findings and p =0.2033 for significant findings). Conclusion: The proportion of intracranial abnormalities detected by CT in this study was similar to that of previous studies. The use of intravenous contrast material administration did not improve its yield. This corroborates the evidence that the ability of CT scan in detecting significant intracranial pathology is poor in patients with chronic headache without neurologic abnormality.DOI: http://dx.doi.org/10.3126/jonmc.v1i2.7301 Journal of Nobel Medical College (2012), Vol.1 No.2 p.57-63

scholarly journals Assessment of DCE Utility for PCa Diagnosis Using PI-RADS v2.1: Effects on Diagnostic Accuracy and Reproducibility

Diagnostics ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 164 ◽  
Author(s):  
Valentina Brancato ◽  
Giuseppe Di Costanzo ◽  
Luca Basso ◽  
Liberatore Tramontano ◽  
Marta Puglia ◽  
...  
Keyword(s):  
Diagnostic Accuracy ◽  
Multiparametric Mri ◽  
Added Value ◽  
Operating Characteristics ◽  
Dce Mri ◽  
Contrast Enhanced ◽  
Mri Protocol ◽  
Controversial Topic ◽  
Clinically Significant ◽  
Method Agreement

The role of dynamic contrast-enhanced-MRI (DCE-MRI) for Prostate Imaging-Reporting and Data System (PI-RADS) scoring is a controversial topic. In this retrospective study, we aimed to measure the added value of DCE-MRI in combination with T2-weighted (T2W) and diffusion-weighted imaging (DWI) using PI-RADS v2.1, in terms of reproducibility and diagnostic accuracy, for detection of prostate cancer (PCa) and clinically significant PCa (CS-PCa, for Gleason Score ≥ 7). 117 lesions in 111 patients were identified as suspicion by multiparametric MRI (mpMRI) and addressed for biopsy. Three experienced readers independently assessed PI-RADS score, first using biparametric MRI (bpMRI, including DWI and T2W), and then multiparametric MRI (also including DCE). The inter-rater and inter-method agreement (bpMRI- vs. mpMRI-based scores) were assessed by Cohen’s kappa (κ). Receiver operating characteristics (ROC) analysis was performed to evaluate the diagnostic accuracy for PCa and CS-PCa detection among the two scores. Inter-rater agreement was excellent for the three pairs of readers (κ ≥ 0.83), while the inter-method agreement was good (κ ≥ 0.73). Areas under the ROC curve (AUC) showed similar high-values (0.8 ≤ AUC ≤ 0.85). The reproducibility of PI-RADS v2.1 scoring was comparable and high among readers, without relevant differences, depending on the MRI protocol used. The inclusion of DCE did not influence the diagnostic accuracy.

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