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2.
Clin Neuroradiol ; 2024 Mar 25.
Artículo en Inglés | MEDLINE | ID: mdl-38526586

RESUMEN

PURPOSE: Flat-panel detector computed tomography (FDCT) is increasingly used in (neuro)interventional angiography suites. This study aimed to compare FDCT perfusion (FDCTP) with conventional multidetector computed tomography perfusion (MDCTP) in patients with acute ischemic stroke. METHODS: In this study, 19 patients with large vessel occlusion in the anterior circulation who had undergone mechanical thrombectomy, baseline MDCTP and pre-interventional FDCTP were included. Hypoperfused tissue volumes were manually segmented on time to maximum (Tmax) and time to peak (TTP) maps based on the maximum visible extent. Absolute and relative thresholds were applied to the maximum visible extent on Tmax and relative cerebral blood flow (rCBF) maps to delineate penumbra volumes and volumes with a high likelihood of irreversible infarcted tissue ("core"). Standard comparative metrics were used to evaluate the performance of FDCTP. RESULTS: Strong correlations and robust agreement were found between manually segmented volumes on MDCTP and FDCTP Tmax maps (r = 0.85, 95% CI 0.65-0.94, p < 0.001; ICC = 0.85, 95% CI 0.69-0.94) and TTP maps (r = 0.91, 95% CI 0.78-0.97, p < 0.001; ICC = 0.90, 95% CI 0.78-0.96); however, direct quantitative comparisons using thresholding showed lower correlations and weaker agreement (MDCTP versus FDCTP Tmax 6 s: r = 0.35, 95% CI -0.13-0.69, p = 0.15; ICC = 0.32, 95% CI 0.07-0.75). Normalization techniques improved results for Tmax maps (r = 0.78, 95% CI 0.50-0.91, p < 0.001; ICC = 0.77, 95% CI 0.55-0.91). Bland-Altman analyses indicated a slight systematic underestimation of FDCTP Tmax maximum visible extent volumes and slight overestimation of FDCTP TTP maximum visible extent volumes compared to MDCTP. CONCLUSION: FDCTP and MDCTP provide qualitatively comparable volumetric results on Tmax and TTP maps; however, direct quantitative measurements of infarct core and hypoperfused tissue volumes showed lower correlations and agreement.

3.
AJNR Am J Neuroradiol ; 45(2): 163-170, 2024 Feb 07.
Artículo en Inglés | MEDLINE | ID: mdl-38238089

RESUMEN

BACKGROUND AND PURPOSE: Potential utility of flat panel CT perfusion imaging (FPCT-PI) performed immediately after mechanical thrombectomy (MT) is unknown. We aimed to assess whether FPCT-PI obtained directly post-MT could provide additional potentially relevant information on tissue reperfusion status. MATERIALS AND METHODS: This was a single-center analysis of all patients with consecutive acute stroke admitted between June 2019 and March 2021 who underwent MT and postinterventional FPCT-PI (n = 26). A core lab blinded to technical details and clinical data performed TICI grading on postinterventional DSA images and qualitatively assessed reperfusion on time-sensitive FPCT-PI maps. According to agreement between DSA and FPCT-PI, all patients were classified into 4 groups: hypoperfusion findings perfectly matched by location (group 1), hypoperfusion findings mismatched by location (group 2), complete reperfusion on DSA with hypoperfusion on FPCT-PI (group 3), and hypoperfusion on DSA with complete reperfusion on FPCT-PI (group 4). RESULTS: Detection of hypoperfusion (present/absent) concurred in 21/26 patients. Of these, reperfusion findings showed perfect agreement on location and size in 16 patients (group 1), while in 5 patients there was a mismatch by location (group 2). Of the remaining 5 patients with disagreement regarding the presence or absence of hypoperfusion, 3 were classified into group 3 and 2 into group 4. FPCT-PI findings could have avoided TICI overestimation in all false-positive operator-rated TICI 3 cases (10/26). CONCLUSIONS: FPCT-PI may provide additional clinically relevant information in a considerable proportion of patients undergoing MT. Hence, FPCT-PI may complement the evaluation of reperfusion efficacy and potentially inform decision-making in the angiography suite.


Asunto(s)
Isquemia Encefálica , Procedimientos Endovasculares , Accidente Cerebrovascular , Humanos , Prueba de Estudio Conceptual , Tomografía Computarizada por Rayos X/métodos , Accidente Cerebrovascular/diagnóstico por imagen , Accidente Cerebrovascular/cirugía , Trombectomía , Imagen de Perfusión , Resultado del Tratamiento
4.
Phys Med Biol ; 68(20)2023 Oct 02.
Artículo en Inglés | MEDLINE | ID: mdl-37779386

RESUMEN

Objective.Incorporating computed tomography (CT) reconstruction operators into differentiable pipelines has proven beneficial in many applications. Such approaches usually focus on the projection data and keep the acquisition geometry fixed. However, precise knowledge of the acquisition geometry is essential for high quality reconstruction results. In this paper, the differentiable formulation of fan-beam CT reconstruction is extended to the acquisition geometry.Approach.The CT fan-beam reconstruction is analytically derived with respect to the acquisition geometry. This allows to propagate gradient information from a loss function on the reconstructed image into the geometry parameters. As a proof-of-concept experiment, this idea is applied to rigid motion compensation. The cost function is parameterized by a trained neural network which regresses an image quality metric from the motion-affected reconstruction alone.Main results.The algorithm improves the structural similarity index measure (SSIM) from 0.848 for the initial motion-affected reconstruction to 0.946 after compensation. It also generalizes to real fan-beam sinograms which are rebinned from a helical trajectory where the SSIM increases from 0.639 to 0.742.Significance.Using the proposed method, we are the first to optimize an autofocus-inspired algorithm based on analytical gradients. Next to motion compensation, we see further use cases of our differentiable method for scanner calibration or hybrid techniques employing deep models.


Asunto(s)
Redes Neurales de la Computación , Tomografía Computarizada por Rayos X , Fantasmas de Imagen , Tomografía Computarizada por Rayos X/métodos , Algoritmos , Calibración , Procesamiento de Imagen Asistido por Computador/métodos , Tomografía Computarizada de Haz Cónico , Artefactos
5.
PEC Innov ; 2: 100169, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37384150

RESUMEN

Objective: To assess patient experiences using a Shared Decision-Making (SDM) Tool for fertility awareness-based methods (FABMs) of family planning. Methods: The study employed a prospective crossover design to evaluate impact of the SDM tool compared to usual practice when discussing FABMs with patients. Patients completed pre- and post-office visit surveys and an online survey six months later. The primary outcomes evaluated the effect of the SDM tool on patient satisfaction and FABM continuity of use rates. Results: There was no significant difference in likelihood of changing family planning methods immediately after the office visit; however, by six months a significantly larger proportion of patients had started or changed FABMs in the experimental group (52%, 34/66) compared to the control group (36%, 24/66) (p = 0.04). Significantly more patients who used the tool and changed their FABM after their visit reported increased satisfaction with their FABM compared to control (50% vs. 17%, p = 0.022). Conclusions: Use of the SDM tool increased persistent use of and satisfaction with chosen FABMs at six months. Innovations: The novel SDM tool can enhance patients' understanding and facilitate the selection of a more suitable method leading to increased satisfaction.

6.
Transl Stroke Res ; 2023 May 17.
Artículo en Inglés | MEDLINE | ID: mdl-37195548

RESUMEN

Cerebral blood volume mapping can characterize hemodynamic changes within brain tissue, particularly after stroke. This study aims to quantify blood volume changes in the perihematomal parenchyma and pericavity parenchyma after minimally invasive intracerebral hemorrhage evacuation (MIS for ICH). Thirty-two patients underwent MIS for ICH with pre- and post-operative CT imaging and intraoperative perfusion imaging (DynaCT PBV Neuro, Artis Q, Siemens). The pre-operative and post-operative CT scans were segmented using ITK-SNAP software to calculate hematoma volumes and to delineate the pericavity tissue. Helical CT segmentations were registered to cone beam CT data using elastix software. Mean blood volumes were computed inside subvolumes by dilating the segmentations at increasing distances from the lesion. Pre-operative perihematomal blood volumes and post-operative pericavity blood volumes (PBV) were compared. In 27 patients with complete imaging, post-operative PBV significantly increased within the 6-mm pericavity region after MIS for ICH. The mean relative PBV increased by 21.6 and 9.1% at 3 mm and 6 mm, respectively (P = 0.001 and 0.016, respectively). At the 9-mm pericavity region, there was a 2.83% increase in mean relative PBV, though no longer statistically significant. PBV analysis demonstrated a significant increase in pericavity cerebral blood volume after minimally invasive ICH evacuation to a distance of 6 mm from the border of the lesion.

7.
Proc Natl Acad Sci U S A ; 120(2): e2207295120, 2023 01 10.
Artículo en Inglés | MEDLINE | ID: mdl-36598949

RESUMEN

How the growth rate of a microbial population responds to the environmental availability of chemical nutrients and other resources is a fundamental question in microbiology. Models of this response, such as the widely used Monod model, are generally characterized by a maximum growth rate and a half-saturation concentration of the resource. What values should we expect for these half-saturation concentrations, and how should they depend on the environmental concentration of the resource? We survey growth response data across a wide range of organisms and resources. We find that the half-saturation concentrations vary across orders of magnitude, even for the same organism and resource. To explain this variation, we develop an evolutionary model to show that demographic fluctuations (genetic drift) can constrain the adaptation of half-saturation concentrations. We find that this effect fundamentally differs depending on the type of population dynamics: Populations undergoing periodic bottlenecks of fixed size will adapt their half-saturation concentrations in proportion to the environmental resource concentrations, but populations undergoing periodic dilutions of fixed size will evolve half-saturation concentrations that are largely decoupled from the environmental concentrations. Our model not only provides testable predictions for laboratory evolution experiments, but it also reveals how an evolved half-saturation concentration may not reflect the organism's environment. In particular, this explains how organisms in resource-rich environments can still evolve fast growth at low resource concentrations. Altogether, our results demonstrate the critical role of population dynamics in shaping fundamental ecological traits.


Asunto(s)
Aclimatación , Evolución Biológica , Dinámica Poblacional , Adaptación Fisiológica , Nutrientes
8.
J Digit Imaging ; 36(3): 1198-1207, 2023 06.
Artículo en Inglés | MEDLINE | ID: mdl-36650300

RESUMEN

By using Flat detector computed tomography (FD-CT), a one-stop-shop approach in the diagnostic workup of acute ischemic stroke (AIS) might be achieved. Although information on upstream vessels is warranted, dedicated FD-CT protocols which include the imaging of the cervical vasculature are still lacking. We aimed to prospectively evaluate the implementation of a new multimodal FD-CT protocol including cervical vessel imaging in AIS patients. In total, 16 patients were included in this study. Eight patients with AIS due to large vessel occlusion (LVO) prospectively received a fully multimodal FD-CT imaging, including non-enhanced flat detector computed tomography (NE-FDCT), dynamic perfusion flat detector computed tomography (FD-CTP) and flat detector computed tomography angiography (FD-CTA) including cervical imaging. For comparison of time metrics and image quality, eight AIS patients, which received multimodal CT imaging, were included retrospectively. Although image quality of NE-FDCT and FD-CTA was rated slightly lower than NE-CT and CTA, all FD-CT datasets were of diagnostic quality. Intracerebral hemorrhage exclusion and LVO detection was reliably possible. Median door-to-image time was comparable for the FD-CT group and the control group (CT:30 min, IQR27-58; FD-CT:44.5 min, IQR31-55, p = 0.491). Door-to-groin-puncture time (CT:79.5 min, IQR65-90; FD-CT:59.5 min, IQR51-67; p = 0.016) and image-to-groin-puncture time (CT:44 min, IQR30-50; FD-CT:14 min, IQR12-18; p < 0.001) were significantly shorter, when patients were directly transferred to the angiosuite, where FD-CT took place. Our study indicates that using a new fully multimodal FD-CT approach including imaging of cervical vessels for first-line imaging in AIS patients is feasible and comparable to multimodal CT imaging with substantial potential to streamline the stroke workflow.


Asunto(s)
Accidente Cerebrovascular Isquémico , Accidente Cerebrovascular , Humanos , Proyectos Piloto , Estudios Retrospectivos , Accidente Cerebrovascular/diagnóstico por imagen , Tomografía Computarizada por Rayos X/métodos
9.
Diagnostics (Basel) ; 12(10)2022 Oct 09.
Artículo en Inglés | MEDLINE | ID: mdl-36292131

RESUMEN

Single-center comparison of postinterventional multislice computed tomography (MS-CT) and flat-detector computed tomography (FD-CT) in patients with subarachnoid haemorrhage (SAH) and endovascularly treated cerebral aneurysms with a focus on detection of posttherapeutical complications. Patients with endovascularly treated aneurysmal SAH undergoing both MS-CT and FD-CT within 24 h after intervention were included. Datasets were compared regarding image quality (IQ) as well as qualitative (detection of SAH, intracerebral haemorrhage [ICH], intraventricular haemorrhage [IVH], external ventricular drain [EVD] position, acute obstructive hydrocephalus [AOH]) and quantitative (cella media distance [CMD], modified Graeb score [GS]) parameters. 410 patients with endovascularly treated aneurysmal SAH were included. IQ was equal between MS-CT and FD-CT. FD-CT allowed equal detection of SAH and ICH in comparison to MS-CT. FD-CT allowed excellent detection of IVH and delineation of EVD position with strong agreement to MS-CT findings. FD-CT allowed equal detection of AOH in comparison to MS-CT. There was no significant difference of CMD and GS between FD-CT and MS-CT. Postinterventional FD-CT yields equivalent diagnostic value in patients with endovascular treated SAH as MS-CT. Enabling reliable detection of SAH-associated complications within the angiosuite, FD-CT might be an efficient and safe imaging modality in these clinical emergencies.

10.
Contraception ; 115: 12-16, 2022 11.
Artículo en Inglés | MEDLINE | ID: mdl-35901971

RESUMEN

OBJECTIVE: The Natural Cycles app employs daily basal body temperature to define the fertile window via a proprietary algorithm and is clinically established effective in preventing pregnancy. We sought to (1) compare the app-defined fertile window of Natural Cycles to that of CycleProGo, an app that uses BBT and cervical mucus to define the fertile window and (2) compare the app-defined fertile windows to the estimated physiologic fertile window. STUDY DESIGN: Daily BBT were entered into Natural Cycles from 20 randomly selected regularly cycling women with at least 12 complete cycles from the CycleProGo database. The proportion of cycles with equivalent (±1 cycle day) fertile-window starts and fertile-window ends was determined. The app-defined fertile windows were then compared to the estimated physiologic fertile window using Peak mucus to estimate ovulation. RESULTS: Fifty seven percent of cycles (136/238) had equivalent fertile-window starts and 36% (72/181) had equivalent fertile-window end days. The mean overall fertile-window length from Natural Cycles was 12.8 days compared to 15.1 days for CycleProGo (p < 0.001). The Natural Cycles algorithm declared 12% to 30% of cycles with a fertile-window start and 13% to 38% of cycles with a fertile-window end within the estimated physiologic fertile window. The CycleProGo algorithm declared 4% to 14% of cycles with a fertile-window start and no cycles with a fertile-window end within the estimated physiologic fertile window. CONCLUSIONS: Natural Cycles designated a higher proportion of cycles days as infertile within the estimated physiologic fertile window than CycleProGo. IMPLICATIONS: Use of cervical mucus in addition to BBT may improve the accuracy of identifying the fertile window. Additional studies with other markers of ovulation and the fertile window would give additional insight into the clinical implications of app-defined fertile window differences.


Asunto(s)
Aplicaciones Móviles , Moco del Cuello Uterino , Femenino , Fertilidad/fisiología , Humanos , Métodos Naturales de Planificación Familiar , Ovulación , Detección de la Ovulación , Embarazo
11.
J Womens Health (Larchmt) ; 31(8): 1097-1102, 2022 08.
Artículo en Inglés | MEDLINE | ID: mdl-35723654

RESUMEN

Background: Some studies have suggested minor changes in the menstrual cycle after COVID-19 vaccination, but more detailed analyses of the menstrual cycle are needed to evaluate more specific changes in the menstrual cycle that are not affected by survey-based recall bias. Materials and Methods: Using a pretest-post-test quasi-experimental evaluation of menstrual cycle parameters before and after COVID-19 vaccination, we conducted an anonymous online survey of two groups of North American women who prospectively monitor their menstrual cycle parameters daily including bleeding patterns, urinary hormone levels using the ClearBlue Fertility Monitor, or cervical mucus observations. The primary outcome measures were cycle length, length of menses, menstrual volume, estimated day of ovulation (EDO), luteal phase length, and signs of ovulation. Perceived (subjective) menstrual cycle changes and stressors were also evaluated in this study as secondary outcome measures. Results: Of the 279 women who initiated the survey, 76 met the inclusion criteria and provided 588 cycles for analysis (227 pre-vaccine cycles, 145 vaccine cycles, 216 post-vaccine cycles). Although 22% of women subjectively identified changes in their menstrual cycle, there were no significant differences in menstrual cycle parameters (cycle length, length of menses, EOD, and luteal phase length) between the pre-vaccine, vaccine, and post-vaccine cycles. Conclusions: COVID-19 vaccines were not associated with significant changes in menstrual cycle parameters. Perceived changes by an individual woman must be compared with statistical changes to avoid confirmation bias.


Asunto(s)
Vacunas contra la COVID-19 , COVID-19 , COVID-19/prevención & control , Femenino , Humanos , Fase Luteínica/orina , Ciclo Menstrual , Progesterona , Vacunación
12.
Diagnostics (Basel) ; 12(5)2022 May 04.
Artículo en Inglés | MEDLINE | ID: mdl-35626296

RESUMEN

Treated cerebral aneurysms (IA) require follow-up imaging to ensure occlusion. Metal artifacts complicate radiologic assessment. Our aim was to evaluate an innovative metal-artifact-reduction (iMAR) algorithm for flat-detector computed tomography angiography (FD-CTA) regarding image quality (IQ) and detection of aneurysm residua/reperfusion in comparison to 2D digital subtraction angiography (DSA). Patients with IAs treated by endovascular coiling or clipping underwent both FD-CTA and DSA. FD-CTA datasets were postprocessed with/without iMAR algorithm (MAR+/MAR−). Evaluation of all FD-CTA and DSA datasets regarding qualitative (IQ, MAR) and quantitative (coil package diameter/CPD) parameters was performed. Aneurysm occlusion was assessed for each dataset and compared to DSA findings. In total, 40 IAs were analyzed (ncoiling = 24; nclipping = 16). All iMAR+ datasets demonstrated significantly better IQ (pIQ coiling < 0.0001; pIQ clipping < 0.0001). iMAR significantly reduced the metal-artifact burden but did not affect the CPD. iMAR significantly improved the detection of aneurysm residua/reperfusion with excellent agreement with DSA (naneurysm detection MAR+/MAR−/DSA = 22/1/26). The iMAR algorithm significantly improves IQ by effective reduction of metal artifacts in FD-CTA datasets. The proposed algorithm enables reliable detection of aneurysm residua/reperfusion with good agreement to DSA. Thus, iMAR can help to reduce the need for invasive follow-up in treated IAs.

13.
Neuroradiology ; 64(7): 1437-1445, 2022 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-35410396

RESUMEN

PURPOSE: Flat-detector computed tomography (FD-CT) is the standard for cochlear implant (CI) imaging. FD-CT systems differ in technical characteristics. Our aim was an evaluation of two different FD-CT generations with different protocols and hardware regarding image quality, radiation dose, and scan time. METHODS: Two temporal bone specimens (- / + CI = TB0/TB1) were scanned using three different scanners: two FD-CT systems with different scanning protocols (standard FD-CT: 20 s 70 kV, 20 s 109 kV; high-speed FD-CT [HS-FD-CT]: 7 s 109 kV, 9 s 109 kV, 14 s 72 kV) and MS-CT (5 s 120 kV). Acquired datasets were evaluated in consensus reading regarding qualitative and quantitative parameters: addressing CI- and cochlea-specific parameters, cochlea delineation, lamina spiralis ossea visibility, distinction of single CI electrodes, determination of intracochlear implant position, stapes delineation, and mastoidal septation were assessed. Addressing protocol-specific parameters, radiation dose (dose-length-product/DLP), and scan time were assessed. RESULTS: Two HS-FD-CT protocols (14 s/9 s) provide higher or equivalent diagnostic information regarding CI- and cochlea-specific parameters compared to both standard FD-CT protocols. The fastest HS-FD-CT protocol (7 s)-providing inferior diagnostic information compared to all other FD-CT protocols-still exceeds MS-CT. The highest DLP was recorded for the 14 s HS-FD-CT protocol (TB1 = 956 mGycm); the lowest DLPs were recorded for the 7 s HS-FD-CT protocol (TB0 = 188 mGycm) and for MS-CT (TB0 = 138 mGycm), respectively. HS-FD-CT allows a significant reduction of scan time compared to standard FD-CT. CONCLUSION: High-speed FD-CT improves visualization of temporal bone anatomy and postoperative assessment of CIs by combining excellent image quality, fast scan time, and reasonable radiation exposure.


Asunto(s)
Implantes Cocleares , Humanos , Dosis de Radiación , Hueso Temporal/diagnóstico por imagen , Hueso Temporal/cirugía , Tomografía Computarizada por Rayos X/métodos
14.
PEC Innov ; 1: 100061, 2022 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37213746

RESUMEN

Objective: To assess the impact of a Shared Decision-Making (SDM) tool for fertility awareness-based methods (FABMs) of family planning. Methods: Clinicians familiar with at least one FABM were randomly invited to participate in a prospective cross-over study to compare usual practice to the use of the SDM tool when discussing FABMs with patients. Patients completed surveys pre- and post-office visit and six months later. The primary outcome explored the effect of online education on use of the SDM tool on clinicians' knowledge of FABMs. Results: Of 278 clinicians contacted, 54% could not be reached, and 15% did not provide women's health services. The 26 clinicians enrolled were experienced, with more than half recommending FABMs for ≥10 years, and 73% recommending more than one FABM to patients. Knowledge scores significantly improved after online training and use of the SDM tool (baseline mean score = 9.54 (scale of 0-12); post-training mean score = 10.73, p < 0.002). Conclusions: Education about FABMs and training on use of the SDM tool improved knowledge scores even among an experienced cohort of clinicians. Innovation: The novel SDM tool can better equip clinicians to meet the rising patient interest in FABMs.

15.
Linacre Q ; 88(3): 291-316, 2021 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-34565905

RESUMEN

To investigate the sociological, environmental, and economic impact of hormonally active contraceptives, a series of comprehensive literature surveys were employed. Sociological effects are discussed including abortion, exploitation of women, a weakening of marriage, and an increase in divorce with deleterious effects on children such as child poverty, poorer health, lower educational achievement, suicide risks, drug and alcohol abuse, criminality, and incarceration, among others. The environmental impact is discussed briefly and includes the feminization and trans-gendering of male fish downstream from the effluent of city wastewater treatment plants with declining fish populations. The potential economic impact of most of these side effects is estimated based on epidemiologic data and published estimates of costs of caring for the diseases which are linked to the use of hormonally active contraceptives. Hormonally active contraceptives appear to have a deleterious impact on multiple aspects of women's health as well as negative economic and environmental impacts. These risks can be avoided through the use of nonhormonal methods and need to be more clearly conveyed to the public. SUMMARY: Hormonal contraceptives have wide-ranging effects.  The potential economic impact of the medical side effects is estimated. Sociological effects are discussed including abortion, exploitation of women, a weakening of marriage and an increase in divorce with negative effects on children such as child poverty, poorer health, lower educational achievement, suicide risks, drug and alcohol abuse, criminality and incarceration among others. The environmental impact includes hormonal effects on fish with declining fish populations. Women seeking birth control have a right to know about how to avoid these risks by using effective hormone-free methods like Fertility Awareness Methods.

17.
IEEE Trans Med Imaging ; 40(11): 3042-3053, 2021 11.
Artículo en Inglés | MEDLINE | ID: mdl-33844627

RESUMEN

Data truncation is a common problem in computed tomography (CT). Truncation causes cupping artifacts inside the field-of-view (FOV) and anatomical structures missing outside the FOV. Deep learning has achieved impressive results in CT reconstruction from limited data. However, its robustness is still a concern for clinical applications. Although the image quality of learning-based compensation schemes may be inadequate for clinical diagnosis, they can provide prior information for more accurate extrapolation than conventional heuristic extrapolation methods. With extrapolated projection, a conventional image reconstruction algorithm can be applied to obtain a final reconstruction. In this work, a general plug-and-play (PnP) method for truncation correction is proposed based on this idea, where various deep learning methods and conventional reconstruction algorithms can be plugged in. Such a PnP method integrates data consistency for measured data and learned prior image information for truncated data. This shows to have better robustness and interpretability than deep learning only. To demonstrate the efficacy of the proposed PnP method, two state-of-the-art deep learning methods, FBPConvNet and Pix2pixGAN, are investigated for truncation correction in cone-beam CT in noise-free and noisy cases. Their robustness is evaluated by showing false negative and false positive lesion cases. With our proposed PnP method, false lesion structures are corrected for both deep learning methods. For FBPConvNet, the root-mean-square error (RMSE) inside the FOV can be improved from 92HU to around 30HU by PnP in the noisy case. Pix2pixGAN solely achieves better image quality than FBPConvNet solely for truncation correction in general. PnP further improves the RMSE inside the FOV from 42HU to around 27HU for Pix2pixGAN. The efficacy of PnP is also demonstrated on real clinical head data.


Asunto(s)
Artefactos , Tomografía Computarizada por Rayos X , Algoritmos , Tomografía Computarizada de Haz Cónico
18.
Linacre Q ; 88(2): 126-148, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-33897046

RESUMEN

Hormonal contraceptives have been on the market for over fifty years and, while their formulations have changed, the basic mechanism of action has remained the same. During this time, numerous studies have been performed documenting side effects, some of which appear over time, some within weeks or months, but all can have a serious impact on health and quality of life. An effort was made to perform a series of comprehensive literature surveys to better understand immediate and long-term side effects of these agents. The results of this literature review uncovered a number of potential side effects, some of which are acknowledged and many of which are not noted in the prescribing information for these agents. Among the unacknowledged side effects are: an increased risk of HIV transmission for depot medroxyprogesterone acetate (DMPA), and for combination contraceptives breast cancer, cervical cancer, Crohn's disease, ulcerative colitis, systemic lupus erythematosus, depression, mood disorders and suicides (especially among women twenty-five years of age and younger, in the first six months of use), multiple sclerosis, interstitial cystitis, female sexual dysfunction, osteoporotic bone fractures (especially for progesterone-only contraceptives), and fatty weight gain. Misleading prescribing information regarding cardiovascular and thrombotic risks are also noted. Women seeking birth control have a right to be informed and educated about risk avoidance through the use of effective nonhormonal methods like fertility awareness methods. In one case-that of DMPA-the increased risk of HIV acquisition has been conclusively demonstrated to be both real and unique to this drug. Considering the availability of numerous alternatives, there is no justification for the continued marketing of DMPA to the public. SUMMARY: We reviewed the effect of hormonal contraceptives on women's health. A number of potential side effects were noted including increased risks of breast cancer, cervical cancer, inflammatory bowel  disease, lupus, multiple sclerosis, cystitis, bone fractures, depression, mood disorders and suicides,  fatty weight gain, and female sexual dysfunction.  With the long-acting injectable contraceptives there is an increased risk of getting HIV.  Misleading prescribing information regarding the risks of heart attacks, strokes and blood clotting problems were also noted. Women seeking birth control have a right to know about how to avoid these risks by using effective hormone-free Fertility Awareness Methods.

19.
Linacre Q ; 88(1): 42-55, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-33487745

RESUMEN

Marital chastity is the practice of periodic abstinence with use of natural family planning (NFP). The purpose of this study was to determine the influence of the most common methods of contraception (female sterilization, oral contraceptive pills, and condoms) and NFP on divorce/separation and cohabitation rates among reproductive age women. The study involved an extensive review of the literature on the effects of practice of NFP on marital dynamics and a statistical analysis of 2,550 ever-married women in the (2015-2017) National Survey of Family Growth data set. Importance of religion and frequency of church attendance were included in the analysis. With ever-use of NFP, 14 percent were divorced or separated, and 27 percent to 39 percent were divorced or separated with ever-use of oral contraceptive pills. Stepwise logistic regression indicated that ever-use of contraception was associated with increased odds of divorce or separation (odds ratio [OR] = 2.05; confidence interval [CI]: 1.96-2.49) and cohabitation (2.95, CI: 2.20-3.95). Ever-use of NFP yielded 58 percent lower odds for divorce or separation. Frequent church attendance was associated with lower odds of divorce or separation and cohabitation. Although there are lower odds of divorce among NFP users, the reason might be due to their religiosity. SUMMARY: This study showed that ever-use of natural family planning (NFP) among ever-married women was associated with 58 percent lower odds of divorce than among women who never-used NFP. Ever-use of contraceptive methods was associated with two times the odds of divorce and four times for cohabitation compared to those women who never-used those methods. Use of periodic abstinence with NFP is the practice of marital chastity and is thought to strengthen the marital relationship.

20.
IEEE Trans Med Imaging ; 39(11): 3667-3678, 2020 11.
Artículo en Inglés | MEDLINE | ID: mdl-32746114

RESUMEN

In tomographic imaging, anatomical structures are reconstructed by applying a pseudo-inverse forward model to acquired signals. Geometric information within this process is usually depending on the system setting only, i.e., the scanner position or readout direction. Patient motion therefore corrupts the geometry alignment in the reconstruction process resulting in motion artifacts. We propose an appearance learning approach recognizing the structures of rigid motion independently from the scanned object. To this end, we train a siamese triplet network to predict the reprojection error (RPE) for the complete acquisition as well as an approximate distribution of the RPE along the single views from the reconstructed volume in a multi-task learning approach. The RPE measures the motion-induced geometric deviations independent of the object based on virtual marker positions, which are available during training. We train our network using 27 patients and deploy a 21-4-2 split for training, validation and testing. In average, we achieve a residual mean RPE of 0.013mm with an inter-patient standard deviation of 0.022mm. This is twice the accuracy compared to previously published results. In a motion estimation benchmark the proposed approach achieves superior results in comparison with two state-of-the-art measures in nine out of twelve experiments. The clinical applicability of the proposed method is demonstrated on a motion-affected clinical dataset.


Asunto(s)
Procesamiento de Imagen Asistido por Computador , Tomografía , Artefactos , Humanos , Movimiento (Física) , Tomografía Computarizada por Rayos X
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