Feasibility, Image Quality and Clinical Evaluation of Contrast-Enhanced Breast MRI Performed in a Supine Position Compared to the Standard Prone Position

Background: To assess the feasibility, image quality and diagnostic value of contrast-enhanced breast magnetic resonance imaging (MRI) performed in a supine compared to a prone position. Methods: One hundred and fifty-one patients who had undergone a breast MRI in both the standard prone and supine position were evaluated retrospectively. Two 1.5 T MR scanners were used with the same image resolution, sequences and contrast medium in all examinations. The image quality and the number and dimensions of lesions were assessed by two expert radiologists in an independent and randomized fashion. Two different classification systems were used. Histopathology was the standard of reference. Results: Two hundred and forty MRIs from 120 patients were compared. The analysis revealed 134 MRIs with monofocal (U), 68 with multifocal (M) and 38 with multicentric (C) lesions. There was no difference between the image quality and number of lesions in the prone and supine examinations. A significant difference in the lesion extension was observed between the prone and supine position. No significant differences emerged in the classification of the lesions detected in the prone compared to the supine position. Conclusions: It is possible to perform breast MRI in a supine position with the same image quality, resolution and diagnostic value as in a prone position. In the prone position, the lesion dimensions are overestimated with a higher wash-in peak than in the supine position.

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Using an Office-Based, Dedicated Extremity MRI Scanner for Depicting Important Structures in Common Wrist Pathologies: A Pilot Comparison with a Conventional MRI Scanner

Journal of Wrist Surgery ◽

10.1055/s-0040-1715799 ◽

2020 ◽

Author(s):

Qi Yin ◽

Radu A. Manoliu ◽

Jayant R. Kichari ◽

Marco J. P. F. Ritt

Keyword(s):

Image Quality ◽

Diagnostic Value ◽

Participant Satisfaction ◽

Conventional Mri ◽

Significant Difference ◽

Magnetic Resonance Imaging Mri ◽

The Right ◽

Carpal Ligaments ◽

Score Point

Abstract Background Compared with the conventional magnetic resonance imaging (MRI), dedicated MRI scanners are more accessible. Images of a dedicated 1.0-T MRI specifically developed for the hand and wrist were compared with images of a conventional 1.5-T MRI. Methods Paired images of the right wrist were randomized and separately graded by two experienced radiologists for the quality of anatomical details, including the triangular fibrocartilage complex, carpal ligaments, intercarpal cartilage, median and ulnar nerves, overall image quality, and artifacts. Interrater reliability was measured with the percentage of exact agreement and agreement within a range of ± 1 score point. Participant experience of undergoing the examination in both MRI scanners was evaluated using a questionnaire. Results The overall image quality of all sequences was considered to be moderate to high. In 25 of 38 paired images, no statistically significant difference was found between the MRI scanners. Ten scores were found to be in favor of the dedicated extremity MRI. Within a range of ± 1 score point, the extremity MRI and the conventional MRI demonstrated an interrater agreement of 67 to 100% and 70 to 100%, respectively. Among the respondents of the questionnaire, the extremity MRI scored better for participant satisfaction when compared with the conventional MRI. Conclusions In healthy volunteers, the dedicated extremity MRI generally is similar or superior to the conventional MRI in the depiction of anatomical structures of the wrists, image quality, and artifacts, and significantly scored better on participant satisfaction. Future clinical studies should focus on defining the diagnostic value of the extremity MRI in wrist pathologies.

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Influence of submaximal isometric contractions of the hamstrings on electromyography activity and force while functioning as hip extensors

Isokinetics and Exercise Science ◽

10.3233/ies-204172 ◽

2020 ◽

pp. 1-8

Author(s):

Dasom Oh ◽

Wootaek Lim

Keyword(s):

Prone Position ◽

Supine Position ◽

Isometric Contraction ◽

Muscle Length ◽

Biceps Femoris ◽

Emg Activity ◽

Isometric Contractions ◽

Significant Difference ◽

Extension Force ◽

Long Head

BACKGROUND: Although the medial and lateral hamstrings are clearly distinct anatomically and have different functions in the transverse plane, they are often considered as one muscle during rehabilitation. OBJECTIVE: The purpose of the study was to compare the electromyographic (EMG) activity between the prone position and the supine position during maximal isometric contraction and to additionally confirm the effect of submaximal isometric contractions on EMG activity of medial and lateral hamstrings, and force. METHODS: In the prone position, EMG activities of the long head of biceps femoris (BFLH) and semitendinosus (ST) were measured during the maximal isometric contraction. In the supine position, hip extension force with EMG activity were measured during the maximal and the submaximal isometric contractions. RESULTS: EMG activity in the prone position was significantly decreased in the supine position. In the supine position, there was a significant difference between the BFLH and ST during the maximal isometric contraction, but not during the submaximal isometric contractions. CONCLUSIONS: The dependence on the hamstrings could be relatively lower during hip extensions. When the medial and lateral hamstrings are considered separately, the lateral hamstrings may show a more active response, with increased muscle length, in clinical practice.

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Evaluation of Shimming Techniques on MRI Breast Image Quality at 1.5T

Journal of Breast Imaging ◽

10.1093/jbi/wbz045 ◽

2019 ◽

Vol 1 (3) ◽

pp. 199-204

Author(s):

Wei Zhou ◽

Christopher P Favazza ◽

Jessica A Axmacher ◽

Joshua D Trzasko ◽

Jennifer R Geske ◽

...

Keyword(s):

Image Quality ◽

Statistical Significance ◽

Breast Mri ◽

Fat Saturation ◽

Institutional Review ◽

Breast Image ◽

Contrast Enhanced ◽

Preparatory Phase ◽

Clinical Mri

Abstract Objective The quality of all clinical MRI is dependent on B0 homogeneity, which is optimized during the shimming part of a prescan or preparatory phase before image acquisition. The purpose of this study was to assess shimming techniques clinically employed for breast MRI across our practice, and to determine factors that correlate with higher image quality for contrast-enhanced breast MRI at 1.5T. Methods One hundred consecutive female patients were retrospectively collected with Institutional Review Board approval. Shimming-related parameters, including shim-box placement and shimming gradient offsets were extracted from prior contrast-enhanced 3D fat-suppressed T1-weighted gradient echo image acquisitions. Three breast radiologists evaluated these images for fat saturation, breast density, overall image quality, and artifacts. Technologist experience was also evaluated for variability of shimming. Generalized linear mixed models were used to compare acquisition parameters between fat saturation. P < 0.05 was considered as statistical significance. Results The percentage of soft tissue inside the field of view (FOV) (ie, Tissue/FOV) in the good fat-saturation group (0.37 ± 0.06) was significantly lower (P < 0.01) than that in the poor fat-saturation group (0.39 ± 0.06). Other shimming-related parameters were found not significantly affecting the fat-saturation outcomes. Technologists with more experience tended to have less variable shimming performance than junior technologists did. Conclusions The quality of clinical MRI and especially breast MRI is highly dependent on shimming. Decreasing Tissue/FOV was associated with good image quality (good fat saturation). Optimization of shimming may require manual shimming or higher-order field-correction strategies.

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Effect of position on the mechanical interaction between the rib cage and abdomen in preterm infants

Journal of Applied Physiology ◽

10.1152/jappl.1992.72.3.1032 ◽

1992 ◽

Vol 72 (3) ◽

pp. 1032-1038 ◽

Cited By ~ 65

Author(s):

M. R. Wolfson ◽

J. S. Greenspan ◽

K. S. Deoras ◽

J. L. Allen ◽

T. H. Shaffer

Keyword(s):

Pulmonary Function ◽

Chest Wall ◽

Preterm Infants ◽

Prone Position ◽

Phase Angle ◽

Supine Position ◽

Pulmonary Mechanics ◽

Rib Cage ◽

Lissajous Figures ◽

Significant Difference

To determine the influence of body position on chest wall and pulmonary function, we studied the ventilatory, pulmonary mechanics, and thoracoabdominal motion profiles in 20 preterm infants recovering from respiratory disease who were positioned in both the supine and prone position. Thoracoabdominal motion was assessed from measurements of relative rib cage and abdominal movement and the calculated phase angle (an index of thoracoabdominal synchrony) of the rib and abdomen Lissajous figures. The ventilatory and pulmonary function profiles were assessed from simultaneous measurements of transpulmonary pressure, airflow, and tidal volume. The infants were studied in quiet sleep, and the order of positioning was randomized across patients. The results demonstrated no significant difference in ventilatory and pulmonary function measurements as a function of position. In contrast, there was a significant reduction (-49%) in the phase angle of the Lissajous figures and an increase (+66%) in rib cage motion in prone compared with the supine position. In addition, the degree of improvement in phase angle in the prone position was correlated to the severity of asynchrony in the supine position. We speculate that the improvement in thoracoabdominal synchrony in the prone position is related to alterations of chest wall mechanics and respiratory muscle tone mediated by a posturally related shift in the area of apposition of the diaphragm to the anterior inner rib cage wall and increase in passive tension of the muscles of the rib cage. This study suggests that the mechanical advantage associated with prone positioning may confer a useful alternative breathing pattern to the preterm infant in whom elevated respiratory work loads and respiratory musculoskeletal immaturity may predispose to respiratory failure.

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Intra‐arterial magnetic resonance angiography of the iliac arteries: clinical experience using two different protocols

Acta Radiologica ◽

10.1080/02841850510021030 ◽

2005 ◽

Vol 46 (3) ◽

pp. 250-255 ◽

Cited By ~ 1

Author(s):

C. Paetzel ◽

N. Zorger ◽

M. Völk ◽

T. Herold ◽

J. Seitz ◽

...

Keyword(s):

Magnetic Resonance ◽

Magnetic Resonance Angiography ◽

Diagnostic Value ◽

Conventional Angiography ◽

Iliac Arteries ◽

Contrast Enhanced ◽

Group 2 ◽

Magnetic Resonance Imaging Mri ◽

Space Acquisition ◽

Group 1

Purpose: To assess the feasibility of intra‐arterial magnetic resonance angiography (iaMRA) with two different protocols. Material and Methods: Twenty patients were prospectively examined after digital subtraction angiography. Contrast‐enhanced iaMRA was performed using a 1.5T magnetic resonance imaging (MRI) system. Contrast agent (gadodiamide) was injected through a conventional angiography catheter placed in the abdominal aorta. The patients were randomized into two groups each comprising 10 patients. Group 1 was examined with a FLASH‐3D (fast low‐angle shot) sequence, allowing the center of the k‐space to be acquired 0.5 s after initiation of the measurement. Group 2 was examined with the identical sequence, but the center of the k‐space was acquired after 8.7 s. The increase in the intravascular signal intensity was determined and the diagnostic value of the angiograms was independently scored by 4 investigators using a 5‐point scale. Results: Nineteen of 20 MRAs were scored as diagnostic; only 1 was scored as non‐diagnostic by 2 observers. The diagnostic value of the angiograms of group 2 was judged superior to that of group 1 owing to a more homogeneous intravascular contrast distribution. Conclusion: Intra‐arterial MRA is feasible. The diagnostic value of angiograms using a flash sequence with center of the k‐space acquisition after 8.7 s ranged from good to excellent. This sequence is appropriate for iaMRA of iliac arteries to support MR guided intervention.

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DYNAMIC MRI FOR TUMOR ENHANCEMENT: AN EXPERIMENTAL BREAST CANCER MODEL

Biomedical Engineering Applications Basis and Communications ◽

10.4015/s1016237213500117 ◽

2013 ◽

Vol 25 (01) ◽

pp. 1350011 ◽

Cited By ~ 2

Author(s):

Ting-Kai Leung ◽

Pai-Jung Huang ◽

Chi-Ming Lee ◽

Chih-Hsiung Wu ◽

Yi-Fan Chen ◽

...

Keyword(s):

False Positive Rate ◽

Maximum Intensity Projection ◽

Breast Mri ◽

Dynamic Mri ◽

Future Research ◽

Post Processing ◽

Contrast Enhanced ◽

Novel Drugs ◽

Positive Rate ◽

Magnetic Resonance Imaging Mri

Dynamic contrast-enhanced magnetic resonance imaging (MRI) with post-processing is routinely used for the analysis of tumors. However, although breast MRI has gained broad clinical recognition, the relationship between imaging findings and tumor pathogenesis has yet to be fully elucidated. We grafted tumors on rats, to examine dynamic MRI images of the tumors, using post-processing subtraction with 3D maximum intensity projection (sMIP). We established a preliminary platform for analysis to compare hemodynamic-based images with histopathological findings and to further biomolecular research. This platform could facilitate future research on the mechanisms of breast tumor enhancement using MRI, improvements to MRI analysis and reduction of the false positive rate, and the development of novel drugs and contrast media.

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Prone Versus Supine Position in Intubated COVID-19 Patients With ARDS: A Systematic Review and Meta-Analysis

10.21203/rs.3.rs-820756/v1 ◽

2021 ◽

Author(s):

Dita Aditianingsih ◽

Adhrie Sugiarto ◽

Sidharta Kusuma Manggala ◽

Hansen Angkasa ◽

Ahmad Pasha Natanegara

Keyword(s):

Mechanical Ventilation ◽

Mortality Rate ◽

Partial Pressure ◽

Prone Position ◽

Supine Position ◽

Meta Analysis ◽

Arterial Oxygen ◽

Icu Discharge ◽

Significant Difference ◽

Position Group

Abstract BackgroundThis review determined the effect of prone positioning in changes of partial pressure of arterial oxygen/fraction of inspired oxygen (PaO2/FiO2) ratio, partial pressure of carbon dioxide (PaCO2), mortality rate, ICU length of stay and duration of mechanical ventilation in intubated COVID-19 patients with severe ARDS.MethodsA computer-aided comprehensive electronic bibliographic search from MEDLINE, EMBASE, and Science Direct were conducted. The search comprised the articles written in English and intubated adults (≥ 18 years old) patients with COVID-19. The primary outcome was comparing PaO2/FiO2 ratio between prone and supine position group. Secondary outcomes were PaCO2, ICU discharge, and mortality rate. Review Manager version 5.4 (The Cochrane Collaboration) was used for statistical analyses of the included studies.ResultsA total of 7 articles were determined to be eligible, consisting of 1403 intubated COVID-19 patients with ARDS that showed prone position was associated with a higher PaO2/FiO2 ratio compared to supine position (MD 60.17, 95% CI 46.86 - 73.47; p < 0.00001). Four studies reported the PaCO2 measurement and showed no significant difference between prone and supine position (MD 2.07, 95% CI -2.79 - 6.92; p <0.40). Only two studies reported mortalities, one study had 262 deaths out of 648 patients (40.4%) and one study lost 11 out of 20 patients (55%). One study reported median ICU stay and mechanical ventilation duration (16 days) were significantly longer in prone position group.ConclusionThis meta-analysis showed that prone position improved PaO2/FiO2 ratio in intubated COVID-19 patients with ARDS.

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A Novel Device for Smartphone-Based Fundus Imaging and Documentation in Clinical Practice: Comparative Image Analysis Study

JMIR mhealth and uhealth ◽

10.2196/17480 ◽

2020 ◽

Vol 8 (7) ◽

pp. e17480

Author(s):

Maximilian W M Wintergerst ◽

Linus G Jansen ◽

Frank G Holz ◽

Robert P Finger

Keyword(s):

Clinical Practice ◽

Image Quality ◽

Image Acquisition ◽

Posterior Pole ◽

Image Resolution ◽

Imaging Device ◽

Video Mode ◽

Novel Device ◽

Fundus Imaging ◽

Significant Difference

Background Smartphone-based fundus imaging allows for mobile and inexpensive fundus examination with the potential to revolutionize eye care, particularly in lower-resource settings. However, most smartphone-based fundus imaging adapters convey image quality not comparable to conventional fundus imaging. Objective The purpose of this study was to evaluate a novel smartphone-based fundus imaging device for documentation of a variety of retinal/vitreous pathologies in a patient sample with wide refraction and age ranges. Methods Participants’ eyes were dilated and imaged with the iC2 funduscope (HEINE Optotechnik) using an Apple iPhone 6 in single-image acquisition (image resolution of 2448 × 3264 pixels) or video mode (1248 × 1664 pixels) and a subgroup of participants was also examined by conventional fundus imaging (Zeiss VISUCAM 500). Smartphone-based image quality was compared to conventional fundus imaging in terms of sharpness (focus), reflex artifacts, contrast, and illumination on semiquantitative scales. Results A total of 47 eyes from 32 participants (age: mean 62.3, SD 19.8 years; range 7-93; spherical equivalent: mean –0.78, SD 3.21 D; range: –7.88 to +7.0 D) were included in the study. Mean (SD) visual acuity (logMAR) was 0.48 (0.66; range 0-2.3); 30% (14/47) of the eyes were pseudophakic. Image quality was sufficient in all eyes irrespective of refraction. Images acquired with conventional fundus imaging were sharper and had less reflex artifacts, and there was no significant difference in contrast and illumination (P<.001, P=.03, and P=.10, respectively). When comparing image quality at the posterior pole, the mid periphery, and the far periphery, glare increased as images were acquired from a more peripheral part of the retina. Reflex artifacts were more frequent in pseudophakic eyes. Image acquisition was also possible in children. Documentation of deep optic nerve cups in video mode conveyed a mock 3D impression. Conclusions Image quality of conventional fundus imaging was superior to that of smartphone-based fundus imaging, although this novel smartphone-based fundus imaging device achieved image quality high enough to document various fundus pathologies including only subtle findings. High-quality smartphone-based fundus imaging might represent a mobile alternative for fundus documentation in clinical practice.

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New patient-controlled abdominal compression method in radiography: radiation dose and image quality

Acta Radiologica Open ◽

10.1177/2058460118772863 ◽

2018 ◽

Vol 7 (5) ◽

pp. 205846011877286 ◽

Cited By ~ 1

Author(s):

Oili Piippo-Huotari ◽

Eva Norrman ◽

Agneta Anderzén-Carlsson ◽

Håkan Geijer

Keyword(s):

Image Quality ◽

Radiation Dose ◽

Prone Position ◽

Quality Criteria ◽

Abdominal Compression ◽

Radiographic Images ◽

Dose Area Product ◽

Similar Dose ◽

Significant Difference ◽

Area Product

Background The radiation dose for patients can be reduced with many methods and one way is to use abdominal compression. In this study, the radiation dose and image quality for a new patient-controlled compression device were compared with conventional compression and compression in the prone position . Purpose To compare radiation dose and image quality of patient-controlled compression compared with conventional and prone compression in general radiography. Material and Methods An experimental design with quantitative approach. After obtaining the approval of the ethics committee, a consecutive sample of 48 patients was examined with the standard clinical urography protocol. The radiation doses were measured as dose-area product and analyzed with a paired t-test. The image quality was evaluated by visual grading analysis. Four radiologists evaluated each image individually by scoring nine criteria modified from the European quality criteria for diagnostic radiographic images. Results There was no significant difference in radiation dose or image quality between conventional and patient-controlled compression. Prone position resulted in both higher dose and inferior image quality. Conclusion Patient-controlled compression gave similar dose levels as conventional compression and lower than prone compression. Image quality was similar with both patient-controlled and conventional compression and was judged to be better than in the prone position.

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Effects of Desflurane Versus Propofol Anesthesia on Regional Cerebral Oxygenation during Spinal Surgery in the Prone Position

Anesthesia and Clinical Research ◽

10.31487/j.acr.2021.01.02 ◽

2021 ◽

pp. 1-6

Author(s):

Stachtari Chrysoula ◽

Koraki Eleni ◽

Stachtari Chrysoula ◽

Bagntasarian Stella ◽

Gkiouliava Anna ◽

...

Keyword(s):

Prone Position ◽

Supine Position ◽

Spinal Surgery ◽

Cerebral Oxygenation ◽

Demographic Data ◽

Prone Positioning ◽

Anaesthetic Agents ◽

Oxygen Administration ◽

Hemodynamic Variables ◽

Significant Difference

Context: Postural change during anaesthesia has a complex effect on systemic and cerebral circulations. Aim: The goal of the study was to evaluate the effects of desflurane and propofol on cerebral oxygenation during spinal surgery in the prone position. Settings and Design: A prospective randomized double-blinded trial. Methods and Materials: Fifty-two patients scheduled for spinal surgery were randomly allocated to propofol (n=25) and desflurane (n=27) groups. Anaesthetic agents were maintained to obtain a bispectral index of 50-55. SAP, DAP, HR, SPO2, ETCO2 and right and left rSO2 were assessed at seven-time points: supine position without oxygen administration (T1), supine position with oxygen administration (T2-baseline), intubation in the supine position (T3), just after prone positioning (T4), 10 minutes after prone positioning (T5), at the end of surgery in the prone position (T6) and at the end of anaesthesia in the supine position (T7). PCO2, PO2 and Hb partial were also recorded at T3 and T7. Results: Demographic data, pre-oxygenation hemodynamic variables and rSO2 were comparable between the groups. There was no significant difference between groups in SAP, DAP, HR, SPO2, and ETCO2 (p=0.095, p=0.061, p=0.357, p=0.088, p=0.328 respectively). PCO2, PO2 and Hb were not significant different between groups (p=0.542, p=0.394, p=0.768 respectively). rSO2 values were not significantly different between groups. In the propofol group, right rSO2 was significantly higher at T3 (p=0.017) and significantly lower at T5 (p=0,019) and at T6 (p=0,028) compared to baseline. Left rSO2 decreased significantly from baseline at T5 (p=0.026) in the propofol group. Left and right rSO2 in the desflurane group decreased significantly from baseline at T5 (p=0.0004 and p=0.0115). Conclusion: In the prone position, desflurane and propofol were associated with a significant decrease in rSO2 without differences between these anaesthetics.

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