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Atualizado: 2 horas 2 minutos atrás

Mathematical Modeling of Thermal Damage Estimate Volumes in MR-guided Laser Interstitial Thermal Therapy.

2 horas 2 minutos atrás
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Mathematical Modeling of Thermal Damage Estimate Volumes in MR-guided Laser Interstitial Thermal Therapy.

J Neuroimaging. 2021 Jan 20;:

Authors: Liang AS, Munier SM, Danish SF

Abstract
BACKGROUND AND PURPOSE: Magnetic resonance-guided laser interstitial thermal therapy (MRgLITT) is a minimally invasive procedure that produces real-time thermal damage estimates (TDEs) of ablation. Currently, MRgLITT software provides limited quantitative parameters for intraoperative monitoring, but orthogonal TDE-MRI slices can be utilized to mathematically estimate ablation volume. The objective of this study was to model TDE volumes and validate using post-24 hours MRI ablative volumes.
METHODS: Ablations were performed with the Visualase Laser Ablation System (Medtronic). Using ellipsoidal parameters determined for dual-TDEs from orthogonal MRI planes, TDE volumes were calculated by two definite integral methods (A and B) implemented in Matlab (MathWorks). Post-24 hours MRI ablative volumes were measured in OsiriX (Pixmeo) by two-blinded raters and compared to TDE volumes via paired t-test and Pearson's correlations.
RESULTS: Twenty-two ablations for 20 patients with various intracranial pathologies were included. Average TDE volume calculated with method A was 3.44 ± 1.96 cm3 and with method B was 4.83 ± 1.53 cm3 . Method A TDE volumes were significantly different than post-24 hours volumes (P < .001). Method B TDE volumes were not significantly different than post-24 hours volumes (P = .39) and strongly correlated with each other (r = .85, R2 = .72, P < .0001). A total of eight of 22 (36%) method A versus 17 of 22 (77%) method B TDE volumes were within 25% of the post-24 hours ablative volume.
CONCLUSION: We present a viable mathematical method integrating dual-plane TDEs to calculate volumes. Future algorithmic iterations will incorporate additional calculated variables that improve ablative volume estimations.

PMID: 33471941 [PubMed - as supplied by publisher]

3D-Volume Rendering of the Pelvis with Emphasis on Paraurethral Structures Based on MRI Scans and Comparisons between 3D Slicer and OsiriX®.

2 horas 2 minutos atrás
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3D-Volume Rendering of the Pelvis with Emphasis on Paraurethral Structures Based on MRI Scans and Comparisons between 3D Slicer and OsiriX®.

J Med Syst. 2021 Jan 20;45(3):27

Authors: Durnea CM, Siddiqi S, Nazarian D, Munneke G, Sedgwick PM, Doumouchtsis SK

Abstract
The feasibility of rendering three dimensional (3D) pelvic models of vaginal, urethral and paraurethral lesions from 2D MRI has been demonstrated previously. To quantitatively compare 3D models using two different image processing applications: 3D Slicer and OsiriX. Secondary analysis and processing of five MRI scan based image sets from female patients aged 29-43 years old with vaginal or paraurethral lesions. Cross sectional image sets were used to create 3D models of the pelvic structures with 3D Slicer and OsiriX image processing applications. The linear dimensions of the models created using the two different methods were compared using Bland-Altman plots. The comparisons demonstrated good agreement between measurements from the two applications. The two data sets obtained from different image processing methods demonstrated good agreement. Both 3D Slicer and OsiriX can be used interchangeably and produce almost similar results. The clinical role of this investigation modality remains to be further evaluated.

PMID: 33469726 [PubMed - in process]

Anterior epitympanic recess volume and Cog process length in temporal bones with Körner's septum: A radio- anatomical investigation.

2 horas 2 minutos atrás
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Anterior epitympanic recess volume and Cog process length in temporal bones with Körner's septum: A radio- anatomical investigation.

Auris Nasus Larynx. 2021 Jan 16;:

Authors: Hizli O, Bekci T, Aslan S

Abstract
OBJECTIVE: Körner's septum is a dense bony lamina dividing the mastoid cavity into superficial squamous and deeper petrosal portions at the level of antrum. In this study, we aimed at investigating the association of the Körner's septum with the length of the Cog process and the volume of anterior epitympanic recess (AER), using the 3-dimensional reconstruction models based on high resolution computed tomography sections of the temporal bone.
METHODS: Using OsiriX software for MacOS (version 3.8.1, Pixmeo), we measured the volumes from three- dimensional models of anterior epitympanic recess. Anterior epitympanic recess volumes and Cog process lengths of the temporal bones with and without Körner's septum were compared.
RESULTS: Cog process length was significantly higher, and AER volume was significantly lower in patients with Körner's septum compared to the patients without. (p < 0.001). Additionally, Cog process length was significantly (p = 0.008), negatively, but weakly (rho= -0.24) correlated with AER volume.
CONCLUSION: Temporal bones with Körner's septum had a longer Cog process and a smaller AER.

PMID: 33468351 [PubMed - as supplied by publisher]

Evaluation of a model-based attenuation correction method on whole-body 18F-fluorodeoxyglucose positron emission tomography/magnetic resonance imaging.

qua, 01/06/2021 - 08:02
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Evaluation of a model-based attenuation correction method on whole-body 18F-fluorodeoxyglucose positron emission tomography/magnetic resonance imaging.

Radiol Phys Technol. 2021 Jan 05;:

Authors: Kubo H, Nemoto A, Ukon N, Ito H

Abstract
The bone cannot be evaluated using magnetic resonance attenuation correction (MRAC) with the Dixon sequence. To solve this issue, the present study aimed to evaluate model-based AC for whole-body 2-[fluorine-18]-fluoro-2-deoxy-D-glucose (18F-FDG) positron emission tomography (PET)/magnetic resonance imaging (MRI) by creating bone segmentation. We analyzed and evaluated the data of 31 consecutive patients. The Biograph mMR (Siemens Healthcare) was used for clinical whole-body 18F-FDG PET/MRI with the conventional MRAC method, and OSIRIX MD software was used to analyze the images. After the examination, the new model-based post-processing MRAC was applied to create μ-maps with bone segmentation, and retrospective PET reconstruction was performed using this μ-map. The bone structures of all patients created using model-based MRAC were visually evaluated. Standard uptake values (SUVs) at 11 anatomical positions in PET images, corrected using the μ-map with and without bone segmentation, were measured and compared. The model-based post-processing MRAC was run for all patients, without errors. Visual evaluation revealed that the model-based post-processing MRAC exhibited poor results for six patients. Furthermore, it exhibited an increasing trend of SUV in the brain compared to the conventional method. Locations other than the brain indicated a similar or decreasing trend. The two methods showed a good linear correlation for all patients. However, patients aged < 20 years exhibited a different trend from those aged ≥ 20 years. We should exercise caution when applying this model-based MRAC for younger patients.

PMID: 33400065 [PubMed - as supplied by publisher]

Self-reported Dysphagia and Pharyngeal Volume Following Whiplash Injury.

dom, 01/03/2021 - 10:25
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Self-reported Dysphagia and Pharyngeal Volume Following Whiplash Injury.

Dysphagia. 2021 Jan 01;:

Authors: Stone D, Ward EC, Bogaardt H, Heard R, Martin-Harris B, Smith AC, Elliott JM

Abstract
Difficulty swallowing has been reported following whiplash injury; however, the reasons remain poorly understood. A possible factor may be the observed changes in pharyngeal volume. The current exploratory study was designed to examine the prevalence of self-reported dysphagia after whiplash and the relationship with recovery status and change in pharyngeal volume. Data were available from a longitudinal study of adults with whiplash. Data included magnetic resonance imaging (MRI) of the cervical spine, the Dysphagia Handicap Index (DHI), and Neck Disability Index (NDI) collected over four timepoints (< 1 week, 2 weeks, 3 months, and 12 months post-injury). Initial cross-sectional analysis examined 60 patients with DHI data from at least one timepoint. A second, longitudinal analysis was conducted on 31 participants with MRI, NDI, and DHI data at both early (< 1-2 weeks) and late (3-12 months) timepoints. The pharynx was contoured on axial T2-weighted MRI slices using OsiriX image processing software and pharyngeal volume (mm3) was quantified. In the 60-patient cohort, prevalence of self-reported dysphagia (DHI ≥ 3) was observed in 50% of participants at least once in 12 months (M = 4.9, SD 8.16, range 0-40). In the longitudinal cohort (n = 31), mean total DHI significantly (p = 0.006) increased between early and late stages. There was no relationship (p = 1.0) between dysphagia and recovery status, per the NDI% score. Pharyngeal volume remained stable and there was no relationship between dysphagia and pharyngeal volume change (p = 1.0). This exploratory study supports the need for further work to understand the nature of dysphagia, extent of functional compromise, and the underlying pathophysiology post-whiplash.

PMID: 33386482 [PubMed - as supplied by publisher]

Difficult airways: a 3D printing study with virtual fibreoptic endoscopy.

ter, 12/29/2020 - 09:31
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Difficult airways: a 3D printing study with virtual fibreoptic endoscopy.

Br J Oral Maxillofac Surg. 2020 Aug 19;:

Authors: Ormandy D, Kolb B, Jayaram S, Burley O, Kyzas P, Vallance H, Vassiliou L

Abstract
Head and neck cancer patients present unique airway challenges, and oropharyngeal, laryngeal, and hypopharyngeal tumours considerably distort and narrow the anatomy of the airway. We describe the use of 3D augmented reality software combined with 3D printed models to assess the anatomy of difficult airways and to assist in the formulation of the most optimal airway management strategy in such patients. The reported patients had computed tomograms (CT) of the neck prior to their anaesthetic and surgical management. DICOM files of the respective scans were imported to 3D rendering software (OsiriX, Pixmeo). We constructed volume rendered models for initial assessment of the airway then generated serial surface rendered models to create a virtual endoscopic path of the airway to simulate the fibreoptic approach. To further facilitate the study of difficult airways we have subsequently printed 3D models of those that were most difficult using rapid prototyping. Head and neck tumours significantly distort the airway. Thorough study of the relevant anatomy prior to airway management for operating reasons enhances communication between the surgeon and anaesthetist, and aids selection of the most appropriate intubation approach. In conclusion, this paper highlights a useful and novel pre-assessment strategy that allows a virtual, visual, 3-dimensional assessment of the airway anatomy combined with 3D modelling and 3D printing. This enables the airway specialist, anaesthetist, and head and neck surgeon to anticipate any critical steps and adjust the plan accordingly.

PMID: 33358011 [PubMed - as supplied by publisher]

Pediatric Rhabdomyosarcomas: Three-Dimensional Radiological Assessments after Induction Chemotherapy Predict Survival Better than One-Dimensional and Two-Dimensional Measurements.

qua, 12/23/2020 - 08:28
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Pediatric Rhabdomyosarcomas: Three-Dimensional Radiological Assessments after Induction Chemotherapy Predict Survival Better than One-Dimensional and Two-Dimensional Measurements.

Cancers (Basel). 2020 Dec 17;12(12):

Authors: Orsatti G, Morosi C, Giraudo C, Varotto A, Crimì F, Bonzini M, Minotti M, Frigo AC, Zanetti I, Chiaravalli S, Casanova M, Ferrari A, Bisogno G, Stramare R

Abstract
Radiological response to neoadjuvant chemotherapy is currently used to assess the efficacy of treatment in pediatric patients with rhabdomyosarcoma (RMS), but the association between early tumor response on imaging and survival is still controversial. The aim of this study was to investigate the prognostic value of assessing radiological response after induction therapy in pediatric RMS, comparing four different methods. This retrospective, two-center study was conducted on 66 non-metastatic RMS patients. Two radiologists measured tumor size on pre- and post-treatment magnetic resonance (MR) or computed tomography (CT) images using four methods: considering maximal diameter with the 1D-RECIST (Response Evaluation Criteria in Solid Tumors); multiplying the two maximal diameters with the 2D-WHO (World Health Organization); multiplying the three maximal diameters with the 3D-EpSSG (European pediatric Soft tissue sarcoma Study Group); obtaining a software-assisted volume assessment with the 3D-Osirix. Each patient was classified as a responder or non-responder based on the proposed thresholds for each method. Tumor response was compared with survival using Kaplan-Meier plots, the log-rank test, and Cox's regression. Agreement between methods and observers (weighted-κ) was also calculated. The 5-year event-free survival (5yr-EFS) calculated with the Kaplan-Meier plots was significantly longer for responders than for non-responders with all the methods, but the 3D assessments differentiated between the two groups better than the 1D-RECIST or 2D-WHO (p1D-RECIST = 0.018, p2D-WHO = 0.007, p3D-EpSSG and p3D-Osirix < 0.0001). Comparing the 5yr-EFS of responders and non-responders also produced adjusted hazard ratios of 3.57 (p = 0.0158) for the 1D-RECIST, 5.05 for the 2D-WHO (p = 0.0042), 14.40 for the 3D-EpSSG (p < 0.0001) and 11.60 for the 3D-Osirix (p < 0.0001), indicating that the volumetric measurements were significantly more strongly associated with EFS. Inter-method agreement was excellent between the 3D-EpSSG and the 3D-Osirix (κ = 0.98), and moderate for the other comparisons (0.5 < κ < 0.8). The 1D-RECIST and the 2D-WHO tended to underestimate response to treatment. Inter-observer agreement was excellent with all methods (κ > 0.8) except for the 2D-WHO (κ = 0.7). In conclusion, early tumor response was confirmed as a significant prognostic factor in RMS, and the 3D-EpSSG and 3D-Osirix methods predicted response to treatment better than the 1D-RECIST or 2D-WHO measurements.

PMID: 33348683 [PubMed]

Comparison of the within-reader and inter-vendor agreement of left ventricular circumferential strains and volume indices derived from cardiovascular magnetic resonance imaging.

qua, 12/16/2020 - 10:21
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Comparison of the within-reader and inter-vendor agreement of left ventricular circumferential strains and volume indices derived from cardiovascular magnetic resonance imaging.

PLoS One. 2020;15(12):e0242908

Authors: Mansell DS, Frank EG, Kelly NS, Agostinho-Hernandez B, Fletcher J, Bruno VD, Sammut E, Chiribiri A, Johnson T, Ascione R, Bartlett JW, Gill HS, Fraser KH, Cookson AN

Abstract
PURPOSE: Volume indices and left ventricular ejection fraction (LVEF) are routinely used to assess cardiac function. Ventricular strain values may provide additional diagnostic information, but their reproducibility is unclear. This study therefore compares the repeatability and reproducibility of volumes, volume fraction, and regional ventricular strains, derived from cardiovascular magnetic resonance (CMR) imaging, across three software packages and between readers.
METHODS: Seven readers analysed 16 short-axis CMR stacks of a porcine heart. Endocardial contours were manually drawn using OsiriX and Simpleware ScanIP and repeated in both softwares. The images were also contoured automatically in Circle CVI42. Endocardial global, apical, mid-ventricular, and basal circumferential strains, as well as end-diastolic and end-systolic volume and LVEF were compared.
RESULTS: Bland-Altman analysis found systematic biases in contour length between software packages. Compared to OsiriX, contour lengths were shorter in both ScanIP (-1.9 cm) and CVI42 (-0.6 cm), causing statistically significant differences in end-diastolic and end-systolic volumes, and apical circumferential strain (all p<0.006). No differences were found for mid-ventricular, basal or global strains, or left ventricular ejection fraction (all p<0.007). All CVI42 results lay within the ranges of the OsiriX results. Intra-software differences were found to be lower than inter-software differences.
CONCLUSION: OsiriX and CVI42 gave consistent results for all strain and volume metrics, with no statistical differences found between OsiriX and ScanIP for mid-ventricular, global or basal strains, or left ventricular ejection fraction. However, volumes were influenced by the choice of contouring software, suggesting care should be taken when comparing volumes across different software.

PMID: 33320865 [PubMed - as supplied by publisher]

Effect of postoperative radiotherapy for free flap volume changing after tongue reconstruction.

seg, 11/16/2020 - 23:41
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Effect of postoperative radiotherapy for free flap volume changing after tongue reconstruction.

Oral Radiol. 2020 Nov 12;:

Authors: Yamazaki M, Suzuki T, Hiraga C, Yoshida Y, Baba A, Saitou H, Ogane S, Fujii T, Takano M, Katakura A, Tanaka I, Nomura T, Takano N

Abstract
OBJECTIVE: The purpose of this study was to evaluate the effect of postoperative radiotherapy (RT) on temporal volume changes with a cutaneous free flap (CF) and a myocutaneous free flap (MCF).
METHODS: The subjects were 24 men and 11 women (mean age, 50.5 ± 15.5 years) with tongue or floor of mouth cancer. Twenty-seven cases of CF and eight cases of MCF were selected. The flap volume change of the reconstructed tongue was calculated using computed tomography (CT) images taken immediately and at one year postoperatively using the DICOM image processing software OsiriX®.
RESULTS: The reduction rate in flap volume at one year postoperatively was 82.0 ± 15% in CF without RT, 70.3 ± 26.1% in CF with RT, 88.5 ± 14.7% in MCF without RT, and 99.5 ± 16% in MCF with RT. The MCF volume was significantly higher compared to the CF volume. Although postoperative RT reduced the CF volume by 30%, there was only a slight reduction in the MCF volume.
CONCLUSIONS: We evaluated the effect of postoperative RT on volume reduction in 35 cases of the reconstructed tongue with CF and MCF using a computer-assisted volume rendering technique. In this study, the effect of RT on volume reduction was different between the CF and MCF.

PMID: 33184774 [PubMed - as supplied by publisher]

Anatomical variants of the celiac trunk.

qui, 11/12/2020 - 17:02
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Anatomical variants of the celiac trunk.

Morphologie. 2020 Nov 07;:

Authors: Laleye CM, Ahouansou PY, Hounton SED, Videgla LB, Hadonou AA, Agossou AC, Attolou SG, Dibert-Bekoy-Nouganga E, Biaou O, Hounnou GM, Mehinto, Voyeme AK

Abstract
AIM OF THE STUDY: Determine the anatomical variants of the celiac trunk and describe it in its modal form using a scanner.
PATIENTS: In total, 200 patients were included in this study.
MATERIAL AND METHODS: The study was carried out using a multi-detector scanner (SIEMENS Somatom Emotion Excel Edition, 16 bars). The two-dimensional and three-dimensional reconstructions by volume were made with the OSIRIX software. It was a retrospective study. The study had taken into account the result of the abdominal scanners injected carried out from December 15, 2018 to February 15, 2019 i.e. 14 months (1 year 2 months).
RESULTS: A predominance of type I of UFLACKER is 93.50% with a rate of change from normal of 6.50%. A vertebral projection of the origin of the celiac trunk at the level of the T12-L1 intervertebral disc was observed in 52.80%. An existence of collateral branches in 7.5% of cases. Other terminal branches apart from the three classics were found in 8.5% of the cases.
CONCLUSION: These variants deserve special attention in the case of a pre-therapeutic vascular assessment for the surgical or interventional management of tumors and trauma of the supra-meso-colic viscera or even for organ transplantation.

PMID: 33172784 [PubMed - as supplied by publisher]

High accuracy of external ventricular drainage placement using anatomical landmarks.

qua, 10/21/2020 - 07:15

High accuracy of external ventricular drainage placement using anatomical landmarks.

Neurochirurgie. 2020 Oct 17;:

Authors: Brenke C, Fürst J, Katsigiannis S, Carolus AE

Abstract
BACKGROUND: The conventional approach for external ventricular drainage (EVD) application is the freehand method. Technical devices can improve the accuracy of placement, but they have not yet replaced anatomical landmarks owing to the cost and effort that they entail. There is disagreement as to whether freehand EVD application is safe enough to be accepted as a standard technique. Many authors have investigated the final catheter position in retrospect. They describe variable rates of malpositioning. However, few studies have assessed in how far cranial surface anatomy has really been respected during burr-hole drilling and catheter insertion. The aim of this study was to investigate parameters that might play a part in determining the final intracranial catheter position.
METHODS: 100 pre- and postprocedural thin-layer computed-tomography (CT) scans of EVD patients were analysed with the help of JiveX® and OsiriX Lite® software. A series of anatomical and catheter-related parameters, including inter alia intraventricular blood, midline shift, burr-hole location and catheter entrance angle, were correlated with the final catheter position.
RESULTS: A majority of EVDs show an optimal or nearly optimal position. Only the deviation of catheter entrance angle has a significant influence on catheter malpositioning. The burr-hole location can vary within an area of several centimetres around the coronary suture.
CONCLUSIONS: The freehand application of EVD is safe as long as the intracranial anatomy is not disfigured to a large extent, the surface measurements are carried out precisely and the puncturing is done perpendicularly to the skull.

PMID: 33080249 [PubMed - as supplied by publisher]

New method for quantification of severity of isolated scaphocephaly linked to intracranial volume.

seg, 10/19/2020 - 22:01

New method for quantification of severity of isolated scaphocephaly linked to intracranial volume.

Childs Nerv Syst. 2020 Oct 18;:

Authors: Kronig ODM, Kronig SAJ, Van Adrichem LNA

Abstract
PURPOSE: The aim is to implement Utrecht Cranial Shape Quantificator (UCSQ) for quantification of severity of scaphocephaly and compare UCSQ with the most used quantification method, cranial index (CI). Additionally, severity is linked to intracranial volume (ICV).
METHODS: Sinusoid curves of 21 pre-operative children (age < 2 years) with isolated scaphocephaly were created. Variables of UCSQ (width of skull and maximum occiput and forehead) were combined to determine severity. CI was calculated. Three raters performed visual scoring for clinical severity (rating of 6 items; total score of 12 represents most severe form). Pearson's correlation test was used for correlation between UCSQ and visual score and between both CIs. ICV was calculated using OsiriX. ICV was compared to normative values and correlated to severity.
RESULTS: Mean UCSQ was 22.00 (2.00-42.00). Mean traditional CI was 66.01 (57.36-78.58), and mean visual score was 9.1 (7-12). Correlations between both traditional CI and CI of UCSQ and overall visual scores were moderate and high (r = - 0.59; p = 0.005 vs. r = - 0.81; p < 0.000). Mean ICV was 910 mL (671-1303), and ICV varied from decreased to increased compared to normative values. Negligible correlation was found between ICV and UCSQ (r = 0.26; p > 0.05) and between ICV and CI and visual score (r = - 0.30; p > 0.05 and r = 0.17; p > 0.05, respectively).
CONCLUSION: Our current advice is to use traditional CI in clinical practice; it is easy to use and minimally invasive. However, UCSQ is more precise and objective and captures whole skull shape. Therefore, UCSQ is preferable for research. Additionally, more severe scaphocephaly does not result in more deviant skull volumes.

PMID: 33070215 [PubMed - as supplied by publisher]

Peritoneal cavity circumference on computed tomography predicts outcomes in acute pancreatitis.

qua, 10/14/2020 - 15:21

Peritoneal cavity circumference on computed tomography predicts outcomes in acute pancreatitis.

Eur J Radiol. 2020 Oct 03;132:109327

Authors: Monreal-Robles R, Kohn-Gutiérrez AE, Sordia-Ramírez J, Zúñiga-Segura JA, Palafox-Salinas JA, de la Rosa-Pacheco S, Elizondo-Riojas G, González-González JA

Abstract
OBJECTIVES: We investigated the role of novel intra-abdominal parameters measured by computed tomography (CT) in the prediction of clinical outcomes in acute pancreatitis (AP).
METHODS: Patients with AP underwent an abdominal CT scan on admission to define different intra-abdominal parameters (abdominal circumference, peritoneal cavity circumference, intraabdominal visceral fat area, and subcutaneous fat area) at the L2-L3 level using the open-source image analysis software Osirix Lite v.11.0.4 to predict clinical outcomes.
RESULTS: Eighty patients with AP were analyzed. Peritoneal cavity circumference (PCC) was the only variable independently associated with outcomes. PCC showed an area under ROC for prediction of severity in AP of 0.830. A PCC ≥ 85 cm increased the risk of severity of AP (RR 15.7), persistent systemic inflammatory response syndrome (RR 9.3), acute peripancreatic fluid collection (RR 6.4), necrotizing pancreatitis (RR 21.50), and mortality (RR 2.4). We found a 4.7-fold increase in the risk of developing severe AP for each 10 cm increase in PCC.
CONCLUSIONS: PCC measurement at the L2-L3 level using a non-enhanced abdominal CT scan on admission in patients with AP is useful in the early prediction of severity, persistent systemic inflammatory response syndrome, local complications, and mortality.

PMID: 33049650 [PubMed - as supplied by publisher]

Comparison between bracing and hollowing trunk exercise with a focus on the change in T2 values obtained by magnetic resonance imaging.

sex, 10/09/2020 - 08:51

Comparison between bracing and hollowing trunk exercise with a focus on the change in T2 values obtained by magnetic resonance imaging.

PLoS One. 2020;15(10):e0240213

Authors: Muramoto Y, Kuruma H

Abstract
The purpose of this study was to compare the muscle activity of Bracing and Hollowing trunk exercises by means of T2 values using MRI. Subjects were 19 healthy adult males, of whom 10 (with mean height ± SD: 172.3 ± 4.7 cm, mean weight ± SD: 64.3 ± 5.4 kg, mean age ± SD 21.5 ± 1.9 years) performed hollowing and 9 (with mean height ± SD: 171.3 ± 2.1 cm, mean weight ± SD: 68.5 ± 11.7 kg, mean age ± SD: 23.0 ± 2.6 years) performed bracing. They were assessed using MRI. The imaging was completed using Osirix software, which measured T2 values from the transversus abdominis (TrA), internal oblique (IO), external oblique (EO), and multifidus (MF) muscles. Subsequently, T2 values recorded before the exercise were compared with those recorded after the exercise to evaluate the extent of change effected by exercise on the muscles. MRI T2 values indicated that the TrA and IO regions were activated to a significantly greater degree after bracing. No significant changes occurred in any muscle before and after hollowing. It was determined that the activity of the deeper trunk muscles was higher in bracing than in hollowing on comparing the T2 values obtained in the MRI.

PMID: 33031452 [PubMed - as supplied by publisher]

On the Intracochlear Location of Straight Electrode Arrays After Cochlear Implantation: How Lateral Are Lateral Wall Electrodes?

qui, 10/08/2020 - 08:39

On the Intracochlear Location of Straight Electrode Arrays After Cochlear Implantation: How Lateral Are Lateral Wall Electrodes?

Otol Neurotol. 2020 Sep 22;:

Authors: Salcher R, Boruchov A, Timm M, Steffens M, Giesemann A, Lenarz T, Warnecke A

Abstract
OBJECTIVE: Cochlear implants are the gold standard for patients with severe sensorineural hearing loss. A focused electrical stimulation of individual spiral ganglion neurons has not been achieved yet because the scala tympani is a fluid-filled compartment and does not offer a matrix for neuritic outgrowth. Coating of the electrode contacts with swelling hydrogels could fill that gap between the electrode array and the medial wall of the cochlea. Therefore, the exact position of the electrode array within the scala tympani has to be known.
STUDY DESIGN: Retrospective analysis of patient data sets.
SETTING: Tertiary referral center. A total of 95 patients with cochlear implants from one manufacturer were included in this study. The lateral wall, the modiolar wall, and the cochlear implant electrode were segmented using OsiriX MD. For repositioning and reconstructing the respective contours and measuring distances, files were analyzed in MATLAB. The distances from the edge of each electrode contact to the cochlear walls showed no significant differences. But between the different contacts within each patient, there were significant differences. Around 180 degree insertion, electrodes start to get in contact with the lateral wall. The tip of the electrode array was always facing toward the modiolar wall independent of the length of the electrode. We established a method to analyze the position of electrodes within the cochlea.

PMID: 33026778 [PubMed - as supplied by publisher]

Changes of Ocular Dimensions as a Marker of Disease Progression in a Murine Model of Pigmentary Glaucoma.

ter, 10/06/2020 - 08:23

Changes of Ocular Dimensions as a Marker of Disease Progression in a Murine Model of Pigmentary Glaucoma.

Front Pharmacol. 2020;11:573238

Authors: Fiedorowicz M, Wełniak-Kamińska M, Świątkiewicz M, Orzeł J, Chorągiewicz T, Toro MD, Rejdak R, Bogorodzki P, Grieb P

Abstract
Purpose: The elevation of intraocular pressure (IOP), a major risk factor in glaucoma, is an important parameter tracked in experimental models of this disease. However, IOP measurement in laboratory rodents is challenging and may not correlate with some key pathological events that occur in the development of glaucoma. The aims of this study were to quantify changes in ocular morphology in DBA/2J mice that develop spontaneous, age-dependent, pigmentary glaucoma and to check the possible correlation of these parameters with IOP.
Method: Eye morphology was evaluated with MRI in DBA/2J, DBA/2J-Gpnmb+/SjJ, and C57BL/6J female mice ages 3, 6, 9, 12, and 15 months. The animals were anesthetized with isoflurane. A planar receive-only surface coil (inner diameter = 10 mm) was placed over each animal's left eye and the image was acquired with a 7T small animal-dedicated magnetic resonance tomograph and T2-weighted TurboRARE sequence. Ocular dimensions were manually quantitated using OsiriX software. IOP was measured with rebound tonometry.
Results: In the control animals, no age-related changes in the ocular morphology were noted. Since 6 months of age, the anterior chamber deepening and elongation of the eyeballs of DBA/2J mice was detectable. We found a significant, positive correlation between IOP and axial length, anterior chamber area, or anterior chamber width in C57BL/6J mice but not in DBA/2J mice. However, after excluding the measurements performed in the oldest DBA/2J mice (i.e. analyzing only the animals ages 3 to 12 months), we demonstrated a significant positive correlation between IOP and anterior chamber width.
Conclusion: High-resolution magnetic resonance imaging of the eye area in mice enables reproducible and consistent measures of key dimensions of the eyeball. We observed age-dependent alterations in the eye morphology of DBA/2J mice that mostly affected the anterior chamber. We also demonstrated a correlation between some of the ocular dimensions and the IOP of C57Bl/6J mice and DBA/2J mice with moderately advanced glaucomatous pathology.

PMID: 33013417 [PubMed]