Σάββατο, 31 Μαρτίου 2018

Effect of varying computed tomography acquisition and reconstruction parameters on semi-automated clot volume quantification.

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Effect of varying computed tomography acquisition and reconstruction parameters on semi-automated clot volume quantification.

World J Radiol. 2018 Mar 28;10(3):24-29

Authors: Kaufman AE, Pruzan AN, Hsu C, Ramachandran S, Jacobi A, Fayad ZA, Mani V

Abstract
AIM: To examine effects of computed tomography (CT) image acquisition/reconstruction parameters on clot volume quantification in vitro for research method validation purposes.
METHODS: This study was performed in conformance with HIPAA and IRB Regulations (March 2015-November 2016). A ten blood clot phantom was designed and scanned on a dual-energy CT scanner (SOMATOM Force, Siemens Healthcare GmBH, Erlangen, Germany) with varying pitch, iterative reconstruction, energy level and slice thickness. A range of clot and tube sizes were used in an attempt to replicate in vivo emboli found within central and segmental branches of the pulmonary arteries in patients with pulmonary emboli. Clot volume was the measured parameter and was analyzed by a single image analyst using a semi-automated region growing algorithm implemented in the FDA-approved Siemens syngo.via image analysis platform. Mixed model analysis was performed on the data.
RESULTS: On the acquisition side, the continuous factor of energy showed no statistically significant effect on absolute clot volume quantification (P = 0.9898). On the other hand, when considering the fixed factor of pitch, there were statistically significant differences in clot volume quantification (P < 0.0001). On the reconstruction side, with the continuous factor of reconstruction slice thickness no statistically significant effect on absolute clot volume quantification was demonstrated (P = 0.4500). Also on the reconstruction side, with the fixed factor of using iterative reconstructions there was also no statistically significant effect on absolute clot volume quantification (P = 0.3011). In addition, there was excellent R2 correlation between the scale-measured mass of the clots both with respect to the CT measured volumes and with respect to volumes measure by the water displacement method.
CONCLUSION: Aside from varying pitch, changing CT acquisition parameters and using iterative reconstructions had no significant impact on clot volume quantification with a semi-automated region growing algorithm.

PMID: 29599936 [PubMed]



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Submandibular Gland Transfer: A Potential Imaging Pitfall.

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Submandibular Gland Transfer: A Potential Imaging Pitfall.

AJNR Am J Neuroradiol. 2018 Mar 29;:

Authors: Wu X, Yom SS, Ha PK, Heaton CM, Glastonbury CM

Abstract
BACKGROUND AND PURPOSE: The Seikaly and Jha submandibular gland transfer surgery is performed to facilitate gland shielding during radiation therapy for head and neck tumors to circumvent radiation-induced xerostomia. It results in an asymmetric postsurgical appearance of the submandibular and submental spaces. Our purpose was to characterize the morphologic and enhancement characteristics of the transferred submandibular gland and identify potential pitfalls in postoperative radiologic interpretation.
MATERIALS AND METHODS: This retrospective study identified patients with head and neck cancer who had undergone the submandibular gland transfer procedure at our institution. Chart reviews were performed to identify relevant oncologic histories and therapies. CT and MR neck imaging was reviewed to characterize morphologic and enhancement characteristics of the pre- and postoperative submandibular glands, as well as interpretive accuracy.
RESULTS: Eleven patients with oropharyngeal and nasopharyngeal squamous cell carcinomas who underwent submandibular gland transfer were identified. The transferred glands were significantly lengthened in the anteroposterior dimension compared with contralateral glands (P < .001) and displaced anteriorly and inferiorly within the submandibular and submental spaces. Enhancement patterns of the transferred submandibular glands varied, depending on the time of imaging relative to the operation and radiation therapy. Submandibular gland transfer was acknowledged in the postoperative report in 7/11 cases. Errors in interpretation were present in 2/11 reports.
CONCLUSIONS: After the submandibular gland transfer procedure, the submandibular and submental spaces lose their symmetric appearances as the transferred submandibular glands become lengthened and located more anteriorly and inferiorly, with variable enhancement characteristics. Familiarity with the postsurgical appearance of the transferred submandibular glands is key to accurate imaging interpretation.

PMID: 29599172 [PubMed - as supplied by publisher]



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An Update on the Adjunctive Neurovascular Support of Wide-Neck Aneurysm Embolization and Reconstruction Trial: 1-Year Safety and Angiographic Results.

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An Update on the Adjunctive Neurovascular Support of Wide-Neck Aneurysm Embolization and Reconstruction Trial: 1-Year Safety and Angiographic Results.

AJNR Am J Neuroradiol. 2018 Mar 29;:

Authors: Spiotta AM, Chaudry MI, Turner RD, Turk AS, Derdeyn CP, Mocco J, Tateshima S

Abstract
BACKGROUND AND PURPOSE: The safety and efficacy of the PulseRider for the treatment of wide-neck, bifurcation aneurysms at the basilar and carotid terminus locations were studied in a prospective trial, the Adjunctive Neurovascular Support of Wide-Neck Aneurysm Embolization and Reconstruction (ANSWER) trial, reporting on initial 6-month angiographic and clinical results. This report provides insight into the longer term durability and safety with 12-month data.
MATERIALS AND METHODS: Aneurysms treated with the PulseRider among enrolled sites were prospectively studied. Updated 12-month data on clinical and imaging end points are included.
RESULTS: Thirty-four patients were enrolled (29 women, 5 men) with a mean age of 60.9 years. The mean aneurysm height ranged from 2.4 to 15.9 mm with a mean neck size of 5.2 mm (range, 2.3-11.6 mm). At 1 year, there were no device migrations or symptomatic in-stent stenoses. Raymond-Roy I occlusion was achieved in 53% of cases at the time of treatment and progressed to 61% and 67% at 6 and 12 months, respectively. Adequate occlusion (Raymond-Roy I/II) progressed from 88% at 6 months to 90% at 12 months. No recanalizations were observed. There was 1 delayed ischemic event. Good outcome (mRS 0-2) was achieved in 90% of patients.
CONCLUSIONS: The updated 1-year results from the ANSWER trial demonstrate aneurysm stability and an acceptable safety profile for aneurysms treated at the basilar apex and carotid terminus. Prospective data from a larger set of aneurysms treated at other locations are required to assess how treatment with PulseRider compares with alternatives for treating wide-neck bifurcation aneurysms.

PMID: 29599174 [PubMed - as supplied by publisher]



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Parent Artery Reconstruction for Large or Giant Cerebral Aneurysms Using the Tubridge Flow Diverter: A Multicenter, Randomized, Controlled Clinical Trial (PARAT).

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Parent Artery Reconstruction for Large or Giant Cerebral Aneurysms Using the Tubridge Flow Diverter: A Multicenter, Randomized, Controlled Clinical Trial (PARAT).

AJNR Am J Neuroradiol. 2018 Mar 29;:

Authors: Liu JM, Zhou Y, Li Y, Li T, Leng B, Zhang P, Liang G, Huang Q, Yang PF, Shi H, Zhang J, Wan J, He W, Liang C, Zhu G, Xu Y, Hong B, Yang X, Bai W, Tian Y, Zhang H, Li Z, Li Q, Zhao R, Fang Y, Zhao K, PARAT investigators

Abstract
BACKGROUND AND PURPOSE: Although flow diverters have been reported with favorable clinical and angiographic outcomes in various literatures, randomized trials determining their true effectiveness and safety are still in lack. The Parent Artery Reconstruction for Large or Giant Cerebral Aneurysms Using the Tubridge Flow Diverter (PARAT) trial was designed to evaluate the safety and efficacy of the Tubridge flow diverter in the treatment of large or giant aneurysms in comparison with Enterprise stent-assisted coiling.
MATERIALS AND METHODS: This prospective, multicenter, randomized trial was conducted at 12 hospitals throughout China. Enrolled adults with unruptured large/giant intracranial aneurysms were randomly assigned (1:1) to receive either Enterprise stent-assisted coiling or Tubridge flow diverter implantation. The primary end point was complete occlusion at 6-month follow-up, while secondary end points included technical success, mortality, target vessel-related stroke, aneurysm bleeding, in-stent stenosis, parent artery occlusion, and the frequency of all adverse events.
RESULTS: Among 185 enrolled subjects, 41 withdrew before procedure initiation. Overall, 82 subjects underwent Tubridge implantation, and 62 subjects were primarily treated with stent-assisted coiling. The results of 6-month follow-up imaging included complete occlusion rates of 75.34% versus 24.53% for the Tubridge and stent-assisted coiling groups, respectively, with a calculated common odds ratio of 9.4 (95% confidence interval, 4.14-21.38; P < .001). There was a higher, nonsignificant frequency of complications for Tubridge subjects. Multivariate analysis showed a decreased stroke rate at the primary investigational site, with a marginal P value (P = .051).
CONCLUSIONS: This trial showed an obviously higher rate of large and giant aneurysm obliteration with the Tubridge FD over Enterprise stent-assisted coiling. However, this higher obliteration rate came at the cost of a nonsignificantly higher rate of complications. Investigational site comparisons suggested that a learning curve for flow-diverter implantation should be recognized and factored into trial designs.

PMID: 29599173 [PubMed - as supplied by publisher]



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Signal Change of Acute Cortical and Juxtacortical Microinfarction on Follow-Up MRI.

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Signal Change of Acute Cortical and Juxtacortical Microinfarction on Follow-Up MRI.

AJNR Am J Neuroradiol. 2018 Mar 29;:

Authors: Miyata M, Kakeda S, Yoneda T, Ide S, Watanabe K, Moriya J, Korogi Y

Abstract
BACKGROUND AND PURPOSE: Although the clinical importance of cortical microinfarcts has become well-recognized recently, the evolution of cortical microinfarcts on MR imaging is not fully understood. The aim of this study was to examine the temporal changes in acute cortical microinfarcts using susceptibility-weighted imaging and conventional MR imaging.
MATERIALS AND METHODS: Patients with acute infarcts located in the cortical and/or juxtacortical region measuring ≤10 mm in axial diameter based on diffusion-weighted imaging who had a follow-up 3T MR imaging were retrospectively included in the study. All lesions did not show hypointensity on initial T2*WI. For cortical and/or juxtacortical microinfarcts detected on initial DWI, 2 neuroradiologists evaluated the follow-up MR imaging (T2WI, FLAIR, T2*WI, and SWI) and assessed lesion signal intensities and locations (cortical microinfarcts or microinfarcts with juxtacortical white matter involvement).
RESULTS: On initial DWI, 2 radiologists observed 180 cortical and/or juxtacortical microinfarcts in 35 MR imaging examinations in 25 patients; on follow-up, the neuroradiologists identified 29 cortical microinfarcts (16%) on T2WI, 9 (5%) on FLAIR, 4 (2%) on T2*, and 97 (54%) on SWI. All cortical microinfarcts detected with any follow-up MR imaging showed hyperintensity on T2WI/FLAIR and/or hypointensity on T2*WI and SWI.
CONCLUSIONS: SWI revealed conversion (paramagnetic susceptibility changes) of acute cortical microinfarcts, suggesting that a substantial number of cortical microinfarcts may contain hemorrhagic components.

PMID: 29599171 [PubMed - as supplied by publisher]



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Blood Flow Mimicking Aneurysmal Wall Enhancement: A Diagnostic Pitfall of Vessel Wall MRI Using the Postcontrast 3D Turbo Spin-Echo MR Imaging Sequence.

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Blood Flow Mimicking Aneurysmal Wall Enhancement: A Diagnostic Pitfall of Vessel Wall MRI Using the Postcontrast 3D Turbo Spin-Echo MR Imaging Sequence.

AJNR Am J Neuroradiol. 2018 Mar 29;:

Authors: Kalsoum E, Chabernaud Negrier A, Tuilier T, Benaïssa A, Blanc R, Gallas S, Lefaucheur JP, Gaston A, Lopes R, Brugières P, Hodel J

Abstract
Our aim was to compare the detectability of aneurysmal wall enhancement in unruptured intracranial aneurysms between conventional and motion-sensitized driven equilibrium-prepared postcontrast 3D T1-weighted TSE sequences (sampling perfection with applicationoptimized contrasts by using different flip angle evolution, SPACE). Twenty-two patients with 30 unruptured intracranial aneurysms were scanned at 3T. Aneurysmal wall enhancement was more significantly detected using conventional compared with motion-sensitized driven equilibrium-prepared SPACE sequences (10/30 versus 2/30, P < .0001). Contrast-to-noise ratio measurements did not differ between conventional and motion-sensitized driven equilibrium-prepared sequences (P = .51). Flowing blood can mimic aneurysmal wall enhancement using conventional SPACE sequences with potential implications for patient care.

PMID: 29599170 [PubMed - as supplied by publisher]



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Aneurysmal Parent Artery-Specific Inflow Conditions for Complete and Incomplete Circle of Willis Configurations.

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Aneurysmal Parent Artery-Specific Inflow Conditions for Complete and Incomplete Circle of Willis Configurations.

AJNR Am J Neuroradiol. 2018 Mar 29;:

Authors: Cornelissen BMW, Schneiders JJ, Sprengers ME, van den Berg R, van Ooij P, Nederveen AJ, van Bavel E, Vandertop WP, Slump CH, Marquering HA, Majoie CBLM

Abstract
BACKGROUND AND PURPOSE: Hemodynamics are thought to play a role in intracranial aneurysm growth and rupture. Computational fluid dynamics is frequently performed to assess intra-aneurysmal hemodynamics, using generalized flow waveforms of healthy volunteers as inflow boundary conditions. The purpose of this study was to assess differences in inflow conditions for different aneurysmal parent artery locations and variations of circle of Willis configurations.
MATERIALS AND METHODS: In a series of 96 patients with 103 aneurysms, velocity measurements were acquired using 2D phase-contrast MR imaging perpendicular to the aneurysmal parent arteries in the circle of Willis. Circle of Willis configurations were inspected for variations using multiple overlapping thin-slab-acquisition MRAs. Flow rates, velocity magnitudes, and pulsatility indices were calculated for each parent artery location in subgroups of complete and incomplete circle of Willis configurations.
RESULTS: Flow rates, velocity magnitudes, and pulsatility indices were significantly different among aneurysmal parent arteries. Incomplete circle of Willis configurations were observed in 24% of the cases. Significantly lower basilar artery flow rates were observed in configurations with hypoplastic P1 segments. Significantly higher A1 flow rates were observed in configurations with a hypoplastic contralateral A1 segment.
CONCLUSIONS: Inflow conditions vary substantially between aneurysmal parent arteries and circle of Willis configurations. We have created a collection of parent artery-specific inflow conditions tailored to the patient-specific circle of Willis configuration that can be used in future computational fluid dynamics studies analyzing intra-aneurysmal hemodynamics.

PMID: 29599169 [PubMed - as supplied by publisher]



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Appropriateness of tricyclic antidepressants in the geriatric population: A critical interpretation of existing literature.

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Appropriateness of tricyclic antidepressants in the geriatric population: A critical interpretation of existing literature.

Oral Surg Oral Med Oral Pathol Oral Radiol. 2018 Mar 09;:

Authors: Farag AM, Desai B

PMID: 29599082 [PubMed - as supplied by publisher]



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Differentiation Between Brucellar and Tuberculous Spondylodiscitis in the Acute and Subacute Stages by MRI

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Publication date: Available online 30 March 2018
Source:Academic Radiology
Author(s): Xinxin Liu, Hua Li, Chao Jin, Gang Niu, Baoqin Guo, Yi Chen, Jian Yang
Rationale and ObjectivesThe aim of this study was to reveal the distinctive features of magnetic resonance imaging (MRI) for distinguishing brucellar spondylodiscitis (BSD) from tuberculous spondylodiscitis (TSD) in the acute and subacute stages.MethodsThis study involved 14 patients with BSD and 18 patients with TSD from May 2011 to January 2015. BSD was diagnosed based on ≥1/160 titers of a Brucella agglutination test or isolation of Brucella spp. TSD was diagnosed based on the isolation of tuberculosis bacteria. All patients underwent T1- and T2-weight imaging (T1WI and T2WI) and fat suppression T2WI (FS T2WI). The height and the signal intensity (SI) of the vertebra and intervertebral disc were assessed. The distinctive MRI features were compared using the chi-square test. The SI of the vertebra between BSD and TSD was observed in terms of histogram characteristics of kurtosis, skewness, and percentile (75%–25%) on FS T2WI.ResultsTwenty-nine (76.3%) vertebrae of BSD were infected throughout the whole vertebra, and 49 (90.7%) vertebrae of TSD were infected near the osseous end plate (P < .001). Compared to TSD, the vertebral height of BSD was nearly intact (P < .001), owing to the new bone formation in the end plate without vertebral collapse. Furthermore, significant differences in the SI of the vertebra were observed between patients with BSD and TSD in terms of homogeneous characteristics on FS T2WI, that is, kurtosis (BSD vs TSD, 0.107 vs −0.250, P = .023), skewness (BSD vs TSD, −0.021 vs 0.266, P = .017), and percentile (75%–25%) (BSD vs TSD, 54.498 vs 79.399, P = .00049).ConclusionsThe nearly intact vertebra with homogeneous high signal on FS T2WI was an important MRI feature for distinguishing BSD from TSD in the acute and subacute stages.



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Rethinking the PGY-1 Basic Clinical Year

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Publication date: Available online 30 March 2018
Source:Academic Radiology
Author(s): Kathryn E. Darras, Abigail A. Arnold, Colin Mar, Bruce B. Forster, Linda Probyn, Silvia D. Chang
Rationale and ObjectivesRecently, the relevance of the postgraduate year 1 (PGY-1) Basic Clinical Year for radiology residents has been questioned. The purpose of this study was to determine the attitude of radiologists and trainees toward this year and which clinical rotations they perceived as most valuable to clinical practice.Materials and MethodsFollowing institutional review board approval, an anonymous online survey was administered to Canadian radiologists and radiology trainees. In addition to reporting demographic information, respondents were asked to rank the usefulness of individual rotations on a five-point Likert scale. To assess whether there are differences in the ratings and therefore rankings of the rotations by gender, position, and level of training, the Kruskal-Wallis one-way analysis of variance test was used with significance defined as P < .05. The Schulze method was used to rank the perceived usefulness of clinical rotations considered.ResultsOf the 275 respondents, 73.1% were male and 47.3% were trainees. A total of 71.3% of respondents were in favor of the basic clinical year, whereas 16.4% opposed. There was a statistically significant difference between the responses of staff radiologists and trainees, with the staff more strongly favoring the Basic Clinical Year (84.1%) than the trainees (56.9%) (P < .0001). As a whole, the respondents favored general surgery rotations as most relevant to their clinical practice (agreement rate of 48.3%). Interventional radiologists found general and subspecialty surgical rotations to be equally relevant. The rotations deemed to be "essential" were emergency medicine (48.7%) and general surgery (46.6%), and the rotations deemed to be "very useful" were orthopedics (45.8%), trauma (44.4%), neurosurgery (43.3%), neurology (42.2%), and hepatobiliary surgery (38.9%). There was no statistical difference between the respondents' choices based on their level of experience and scope of practice.ConclusionsMost radiologists and radiology trainees were in favor of completing the PGY-1 Basic Clinical Year. However, programs should maximize the education value of this year by including more of the top-ranked rotations. As the practice of radiology evolves, it is important to ensure that training paradigms continue to prepare residents for independent practice.



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Determination of Prostate Volume

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Publication date: Available online 30 March 2018
Source:Academic Radiology
Author(s): Adam Bezinque, Andrew Moriarity, Crystal Farrell, Henry Peabody, Sabrina L. Noyes, Brian R. Lane
Rationale and ObjectivesProstate volume (PV) determination provides important clinical information. We compared PVs determined by digital rectal examination (DRE), transrectal ultrasound (TRUS), magnetic resonance imaging (MRI) with or without three-dimensional (3D) segmentation software, and surgical prostatectomy weight (SPW) and volume (SPV).Materials and MethodsThis retrospective review from 2010 to 2016 included patients who underwent radical prostatectomy ≤1 year after multiparametric prostate MRI. PVs from DRE and TRUS were obtained from urology clinic notes. MRI-based PVs were calculated using bullet and ellipsoid formulas, automated 3D segmentation software (MRI-A3D), manual segmentation by a radiologist (MRI-R3D), and a third-year medical student (MRI-S3D). SPW and SPV were derived from pathology reports. Intraclass correlation coefficients compared the relative accuracy of each volume measurement.ResultsNinety-nine patients were analyzed. Median PVs were DRE 35 mL, TRUS 35 mL, MRI-bullet 49 mL, MRI-ellipsoid 39 mL, MRI-A3D 37 mL, MRI-R3D 36 mL, MRI-S3D 36 mL, SPW 54 mL, SPV-bullet 47 mL, and SPV-ellipsoid 37 mL. SPW and bullet formulas had consistently large PV, and formula-based PV had a wider spread than PV based on segmentation. Compared to MRI-R3D, the intraclass correlation coefficient was 0.91 for MRI-S3D, 0.90 for MRI-ellipsoid, 0.73 for SPV-ellipsoid, 0.72 for MRI-bullet, 0.71 for TRUS, 0.70 for SPW, 0.66 for SPV-bullet, 0.38 for MRI-A3D, and 0.33 for DRE.ConclusionsWith MRI-R3D measurement as the reference, the most reliable methods for PV estimation were MRI-S3D and MRI-ellipsoid formula. Automated segmentations must be individually assessed for accuracy, as they are not always truly representative of the prostate anatomy. Manual segmentation of the prostate does not require expert training.



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Deep Learning in Radiology

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Publication date: Available online 30 March 2018
Source:Academic Radiology
Author(s): Morgan P. McBee, Omer A. Awan, Andrew T. Colucci, Comeron W. Ghobadi, Nadja Kadom, Akash P. Kansagra, Srini Tridandapani, William F. Auffermann
As radiology is inherently a data-driven specialty, it is especially conducive to utilizing data processing techniques. One such technique, deep learning (DL), has become a remarkably powerful tool for image processing in recent years. In this work, the Association of University Radiologists Radiology Research Alliance Task Force on Deep Learning provides an overview of DL for the radiologist. This article aims to present an overview of DL in a manner that is understandable to radiologists; to examine past, present, and future applications; as well as to evaluate how radiologists may benefit from this remarkable new tool. We describe several areas within radiology in which DL techniques are having the most significant impact: lesion or disease detection, classification, quantification, and segmentation. The legal and ethical hurdles to implementation are also discussed. By taking advantage of this powerful tool, radiologists can become increasingly more accurate in their interpretations with fewer errors and spend more time to focus on patient care.



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