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1.
J Natl Compr Canc Netw ; 22(3): 158-166, 2024 04.
Artículo en Inglés | MEDLINE | ID: mdl-38626807

RESUMEN

BACKGROUND: Pancreatic adenocarcinoma (PC) is a highly lethal malignancy with a survival rate of only 12%. Surveillance is recommended for high-risk individuals (HRIs), but it is not widely adopted. To address this unmet clinical need and drive early diagnosis research, we established the Pancreatic Cancer Early Detection (PRECEDE) Consortium. METHODS: PRECEDE is a multi-institutional international collaboration that has undertaken an observational prospective cohort study. Individuals (aged 18-90 years) are enrolled into 1 of 7 cohorts based on family history and pathogenic germline variant (PGV) status. From April 1, 2020, to November 21, 2022, a total of 3,402 participants were enrolled in 1 of 7 study cohorts, with 1,759 (51.7%) meeting criteria for the highest-risk cohort (Cohort 1). Cohort 1 HRIs underwent germline testing and pancreas imaging by MRI/MR-cholangiopancreatography or endoscopic ultrasound. RESULTS: A total of 1,400 participants in Cohort 1 (79.6%) had completed baseline imaging and were subclassified into 3 groups based on familial PC (FPC; n=670), a PGV and FPC (PGV+/FPC+; n=115), and a PGV with a pedigree that does not meet FPC criteria (PGV+/FPC-; n=615). One HRI was diagnosed with stage IIB PC on study entry, and 35.1% of HRIs harbored pancreatic cysts. Increasing age (odds ratio, 1.05; P<.001) and FPC group assignment (odds ratio, 1.57; P<.001; relative to PGV+/FPC-) were independent predictors of harboring a pancreatic cyst. CONCLUSIONS: PRECEDE provides infrastructure support to increase access to clinical surveillance for HRIs worldwide, while aiming to drive early PC detection advancements through longitudinal standardized clinical data, imaging, and biospecimen captures. Increased cyst prevalence in HRIs with FPC suggests that FPC may infer distinct biological processes. To enable the development of PC surveillance approaches better tailored to risk category, we recommend adoption of subclassification of HRIs into FPC, PGV+/FPC+, and PGV+/FPC- risk groups by surveillance protocols.


Asunto(s)
Adenocarcinoma , Neoplasias Pancreáticas , Humanos , Neoplasias Pancreáticas/diagnóstico por imagen , Neoplasias Pancreáticas/epidemiología , Detección Precoz del Cáncer/métodos , Estudios Prospectivos , Predisposición Genética a la Enfermedad , Imagen por Resonancia Magnética
2.
AJR Am J Roentgenol ; 223(2): e2431151, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38809122

RESUMEN

Pancreatic ductal adenocarcinoma (PDA) is one of the most aggressive cancers. It has a poor 5-year survival rate of 12%, partly because most cases are diagnosed at advanced stages, precluding curative surgical resection. Early-stage PDA has significantly better prognoses due to increased potential for curative interventions, making early detection of PDA critically important to improved patient outcomes. We examine current and evolving early detection concepts, screening strategies, diagnostic yields among high-risk individuals, controversies, and limitations of standard-of-care imaging.


Asunto(s)
Carcinoma Ductal Pancreático , Detección Precoz del Cáncer , Neoplasias Pancreáticas , Humanos , Carcinoma Ductal Pancreático/diagnóstico por imagen , Neoplasias Pancreáticas/diagnóstico por imagen , Detección Precoz del Cáncer/métodos , Tamizaje Masivo/métodos , Diagnóstico por Imagen/métodos , Vigilancia de la Población
3.
Radiology ; 308(1): e222778, 2023 07.
Artículo en Inglés | MEDLINE | ID: mdl-37489987

RESUMEN

Pancreatic cystic lesions (PCLs) are widely prevalent and commonly encountered in abdominal radiology. Some PCLs can be definitively identified at imaging as benign subtypes or those with malignant potential, while others remain indeterminate. Notably, the degree of malignant potential and natural history of the most common subtype, branch-duct intraductal papillary mucinous neoplasms, are not clearly established. In the work-up of PCLs, patients may further be identified as high-risk individuals who are at elevated risk of pancreatic ductal adenocarcinoma due to familial and genetic factors. This review describes current PCL surveillance and management guidelines and highlights ongoing controversies and future directions to aid radiologists in their daily practice.


Asunto(s)
Carcinoma Ductal Pancreático , Quiste Pancreático , Neoplasias Pancreáticas , Humanos , Páncreas , Radiólogos
4.
Radiology ; 302(3): 584-592, 2022 03.
Artículo en Inglés | MEDLINE | ID: mdl-34846200

RESUMEN

Background Four-dimensional (4D) flow MRI has the potential to provide hemodynamic insights for a variety of abdominopelvic vascular diseases, but its clinical utility is currently impaired by background phase error, which can be challenging to correct. Purpose To assess the feasibility of using deep learning to automatically perform image-based background phase error correction in 4D flow MRI and to compare its effectiveness relative to manual image-based correction. Materials and Methods A convenience sample of 139 abdominopelvic 4D flow MRI acquisitions performed between January 2016 and July 2020 was retrospectively collected. Manual phase error correction was performed using dedicated imaging software and served as the reference standard. After reserving 40 examinations for testing, the remaining examinations were randomly divided into training (86% [85 of 99]) and validation (14% [14 of 99]) data sets to train a multichannel three-dimensional U-Net convolutional neural network. Flow measurements were obtained for the infrarenal aorta, common iliac arteries, common iliac veins, and inferior vena cava. Statistical analyses included Pearson correlation, Bland-Altman analysis, and F tests with Bonferroni correction. Results A total of 139 patients (mean age, 47 years ± 14 [standard deviation]; 108 women) were included. Inflow-outflow correlation improved after manual correction (ρ = 0.94, P < .001) compared with that before correction (ρ = 0.50, P < .001). Automated correction showed similar results (ρ = 0.91, P < .001) and demonstrated very strong correlation with manual correction (ρ = 0.98, P < .001). Both correction methods reduced inflow-outflow variance, improving mean difference from -0.14 L/min (95% limits of agreement: -1.61, 1.32) (uncorrected) to 0.05 L/min (95% limits of agreement: -0.32, 0.42) (manually corrected) and 0.05 L/min (95% limits of agreement: -0.38, 0.49) (automatically corrected). There was no significant difference in inflow-outflow variance between manual and automated correction methods (P = .10). Conclusion Deep learning automated phase error correction reduced inflow-outflow bias and variance of volumetric flow measurements in four-dimensional flow MRI, achieving results comparable with manual image-based phase error correction. © RSNA, 2021 See also the editorial by Roldán-Alzate and Grist in this issue.


Asunto(s)
Abdomen/irrigación sanguínea , Aprendizaje Profundo , Aumento de la Imagen/métodos , Interpretación de Imagen Asistida por Computador/métodos , Imagen por Resonancia Magnética/métodos , Enfermedades Vasculares/diagnóstico por imagen , Velocidad del Flujo Sanguíneo , Hemodinámica , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos
5.
AJR Am J Roentgenol ; 219(6): 903-914, 2022 12.
Artículo en Inglés | MEDLINE | ID: mdl-35856454

RESUMEN

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive malignancies, with a dismal survival rate. Screening the general population for early detection of PDAC is not recommended, but because early detection improves survival, high-risk individuals, defined as those meeting criteria based on a family history of PDAC and/or the presence of known pathogenic germline variant genes with PDAC risk, are recommended to undergo screening with MRI and/or endoscopic ultrasound at regular intervals. The Pancreatic Cancer Early Detection (PRECEDE) Consortium was formed in 2018 and is composed of gastroenterologists, geneticists, pancreatic surgeons, radiologists, statisticians, and researchers from 40 sites in North America, Europe, and Asia. The overarching goal of the PRECEDE Consortium is to facilitate earlier diagnosis of PDAC for high-risk individuals to increase survival of the disease. A standardized MRI protocol and reporting template are needed to enhance the quality of screening examinations, improve consistency of clinical management, and facilitate multiinstitutional research. We present a consensus statement to standardize MRI screening and reporting for individuals with elevated risk of pancreatic cancer.


Asunto(s)
Carcinoma Ductal Pancreático , Neoplasias Pancreáticas , Humanos , Detección Precoz del Cáncer , Carcinoma Ductal Pancreático/diagnóstico por imagen , Neoplasias Pancreáticas/diagnóstico por imagen , Neoplasias Pancreáticas/genética , Imagen por Resonancia Magnética , Estándares de Referencia , Neoplasias Pancreáticas
6.
J Comput Assist Tomogr ; 46(5): 707-715, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35995483

RESUMEN

ABSTRACT: The role of imaging has been increasing in pretherapy planning and response assessment in cervical cancer, particularly in high-resource settings that provide access to computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET). In 2018, imaging was incorporated into the International Federation of Gynecology and Obstetrics staging system for cervical cancer. Magnetic resonance imaging is advantageous over CT for evaluation of the primary cervical cancer size and extent, because of superior contrast resolution. Furthermore, quantitative methods, including diffusion-weighted and dynamic contrast-enhanced MRI, show promise in improving treatment response and prognosis evaluation. Molecular imaging with fluorodeoxyglucose-PET/CT and PET/MRI can be particularly helpful in the detection of nodal disease and distant metastases. Semiautomated delineation of 3-dimensional tumor regions of interest has facilitated the development of novel PET-derived biomarkers that include metabolic volume and radiomics textural analysis features for prediction of outcomes. However, posttreatment inflammatory changes can be a confounder and lymph node evaluation is challenging, even with the use of PET/CT. Liquid biopsy has emerged as a promising tool that may be able to overcome some of the drawbacks inherent with imaging, such as limited ability to detect microscopic metastases or to distinguish between postchemoradiotherapy changes and residual tumor. Preliminary evidence suggests that liquid biopsy may be able to identify cervical cancer treatment response and resistance earlier than traditional methods. Future work should prioritize how to best synergize imaging and liquid biopsy as an integrated approach for optimal cervical cancer management.


Asunto(s)
Neoplasias del Cuello Uterino , Biomarcadores , Femenino , Fluorodesoxiglucosa F18 , Humanos , Biopsia Líquida , Imagen por Resonancia Magnética/métodos , Estadificación de Neoplasias , Tomografía Computarizada por Tomografía de Emisión de Positrones/métodos , Tomografía de Emisión de Positrones/métodos , Embarazo , Radiofármacos , Neoplasias del Cuello Uterino/diagnóstico por imagen , Neoplasias del Cuello Uterino/patología
7.
Eur Radiol ; 28(5): 2068-2076, 2018 May.
Artículo en Inglés | MEDLINE | ID: mdl-29170798

RESUMEN

OBJECTIVES: To evaluate the feasibility and time saving of fusing CT and MR enterography with ultrasound for ultrasound molecular imaging (USMI) of inflammation in an acute small bowel inflammation of swine. METHODS: Nine swine with ileitis were scanned with either CT (n = 3) or MR (n = 6) enterography. Imaging times to load CT/MR images onto a clinical ultrasound machine, fuse them to ultrasound with an anatomical landmark-based approach, and identify ileitis were compared to the imaging times without anatomical road mapping. Inflammation was then assessed by USMI using dual selectin-targeted (MBSelectin) and control (MBControl) contrast agents in diseased and healthy control bowel segments, followed by ex vivo histology. RESULTS: Cross-sectional image fusion with ultrasound was feasible with an alignment error of 13.9 ± 9.7 mm. Anatomical road mapping significantly reduced (P < 0.001) scanning times by 40%. Localising ileitis was achieved within 1.0 min. Subsequently performed USMI demonstrated significantly (P < 0.001) higher imaging signal using MBSelectin compared to MBControl and histology confirmed a significantly higher inflammation score (P = 0.006) and P- and E-selectin expression (P ≤ 0.02) in inflamed vs. healthy bowel. CONCLUSIONS: Fusion of CT and MR enterography data sets with ultrasound in real time is feasible and allows rapid anatomical localisation of ileitis for subsequent quantification of inflammation using USMI. KEY POINTS: • Real-time fusion of CT/MRI with ultrasound to localise ileitis is feasible. • Anatomical road mapping using CT/MRI significantly decreases the scanning time for USMI. • USMI allows quantification of inflammation in swine, verified with ex vivo histology.


Asunto(s)
Ileítis/diagnóstico , Intestino Delgado/diagnóstico por imagen , Imagen por Resonancia Magnética/métodos , Imagen Molecular/métodos , Tomografía Computarizada por Rayos X/métodos , Ultrasonografía/métodos , Animales , Inflamación/diagnóstico , Porcinos
8.
J Clin Oncol ; : JCO2400511, 2024 Oct 16.
Artículo en Inglés | MEDLINE | ID: mdl-39413348

RESUMEN

PURPOSE: Mucinous neoplasms of the gastrointestinal tract are characterized by a propensity for metastasis to the peritoneum, resulting in peritoneal mucinous carcinomatosis (PMC). A subset of these tumors, most often originating in the appendix, harbor mutations in the GNAS oncogene. While the natural history of GNAS-mutant PMC varies, patient outcomes are generally poor, as is response to cytotoxic chemotherapy. The purpose of this study was to evaluate the clinical efficacy of single-agent palbociclib, a cyclin-dependent kinase (CDK)4/6 inhibitor, in patients with GNAS-mutant PMC. PATIENTS AND METHODS: We enrolled 16 patients with PMC in a single-arm personalized cancer therapy trial. For all patients, tumor tissue and/or circulating tumor DNA genomic profiling using next-generation sequencing and, when possible, PD-L1 expression, tumor mutational burden, and microsatellite instability status was assessed. Twelve of 16 patients had previous disease progression on at least one previous line of chemotherapy. The primary tumor was appendix in 13 patients, unknown in two patients, and pancreas in one patient. Eleven cases were classified as low grade, and five as high grade. RESULTS: In 13 of 16 patients, we observed a decrease in carcinoembryonic antigen (CEA), and in six patients, the CEA declined by >50%. As measured by clinical and modified peritoneal RECIST criteria, 50% of evaluable patients had stable disease after 12 months of palbociclib. At a median follow-up of 17.6 months, median survival has not been reached. Clinical response to CDK4/6 inhibition was mirrored in tumors with GNAS mutation and mucinous histology using an ex vivo preclinical platform. CONCLUSION: CDK4/6 inhibition with palbociclib had clinical activity in PMC characterized by mutations in GNAS that was superior to that previously reported with cytotoxic chemotherapy. CDK4/6 inhibition is a novel therapeutic strategy worthy of further evaluation in this subgroup of gastrointestinal neoplasms.

9.
Neuroimage ; 64: 104-11, 2013 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-22963855

RESUMEN

The blood oxygenation level dependent (BOLD) response measured with functional magnetic resonance imaging (fMRI) depends on the evoked changes in cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO(2)) in response to changes in neural activity. This response is strongly modulated by the CBF/CMRO(2) coupling relationship with activation, defined as n, the ratio of the fractional changes. The reliability of the BOLD signal as a quantitative reflection of underlying physiological changes depends on the stability of n in response to different stimuli. The effect of visual stimulus contrast on this coupling ratio was tested in 9 healthy human subjects, measuring CBF and BOLD responses to a flickering checkerboard at four visual contrast levels. The theory of the BOLD effect makes a robust prediction-independent of details of the model-that if the CBF/CMRO(2) coupling ratio n remains constant, then the response ratio between the lowest and highest contrast levels should be higher for the BOLD response than the CBF response because of the ceiling effect on the BOLD response. Instead, this response ratio was significantly lower for the BOLD response (BOLD response: 0.23 ± 0.13, mean ± SD; CBF response: 0.42 ± 0.18; p=0.0054). This data is consistent with a reduced dynamic range (strongest/weakest response ratio) of the CMRO(2) response (~1.7-fold) compared to that of the CBF response (~2.4-fold) as luminance contrast increases, corresponding to an increase of n from 1.7 at the lowest contrast level to 2.3 at the highest contrast level. The implication of these results for fMRI studies is that the magnitude of the BOLD response does not accurately reflect the magnitude of underlying physiological processes.


Asunto(s)
Mapeo Encefálico/métodos , Encéfalo/fisiología , Circulación Cerebrovascular/fisiología , Imagen por Resonancia Magnética/métodos , Consumo de Oxígeno/fisiología , Oxígeno/sangre , Estimulación Luminosa/métodos , Adulto , Femenino , Humanos , Masculino , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Adulto Joven
10.
J Magn Reson Imaging ; 35(2): 318-27, 2012 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-21959926

RESUMEN

PURPOSE: To characterize cardiac motion artifacts in the liver and assess the use of a postprocessing method to mitigate these artifacts in repeat measurements. MATERIALS AND METHODS: Three subjects underwent breathhold diffusion-weighted (DW) scans consisting of 25 repetitions for three b-values (0, 500, 1000 sec/mm(2)). Statistical maps computed from these repetitions were used to assess the distribution and behavior of cardiac motion artifacts in the liver. An objective postprocessing method to reduce the artifacts was compared with radiologist-defined gold standards. RESULTS: Signal dropout is pronounced in areas proximal to the heart, such as the left lobe, but also present in the right lobe and in distal liver segments. The dropout worsens with b-value and leads to overestimation of the diffusivity. By reference to a radiologist-defined gold standard, a postprocessing correction method is shown to reduce cardiac motion artifact. CONCLUSION: Cardiac motion leads to significant artifacts in liver DW imaging; we propose a postprocessing method that may be used to mitigate the artifact and is advantageous to standard signal averaging in acquisitions with multiple repetitions.


Asunto(s)
Imagen de Difusión por Resonancia Magnética/métodos , Contracción Miocárdica/fisiología , Adulto , Anciano , Artefactos , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador/métodos , Hígado , Masculino , Movimiento (Física) , Relación Señal-Ruido
11.
Aliment Pharmacol Ther ; 55(7): 820-827, 2022 04.
Artículo en Inglés | MEDLINE | ID: mdl-35229334

RESUMEN

BACKGROUND: Retrospective studies report that visualisation of the liver may be severely limited using ultrasound (US), potentially contributing to diminished sensitivity for detection of hepatocellular carcinoma (HCC) among patients with nonalcoholic fatty liver disease (NAFLD) and cirrhosis, but there are limited prospective data. AIMS: To compare liver visualisation scores prospectively for US and abbreviated hepatobiliary phase (HBP) magnetic resonance imaging (AMRI) in a cohort of participants with NAFLD cirrhosis and a clinical indication for HCC surveillance. METHODS: This prospective multicenter study included 54 consecutive participants (67% women) with NAFLD cirrhosis who underwent contemporaneous US as well as HBP-AMRI with gadoxetic acid. Primary outcome was the proportion of imaging examinations with severe limitations in liver visualisation (visualisation score C) compared head-to-head between US and AMRI. RESULTS: The mean (± standard deviation) age was 63.3 years (±8.4) and body mass index was 32.0 kg/m2 (±6.0). Nineteen participants (35%) had severe visualisation limitations on US, compared with 10 (19%) with AMRI, p < 0.0001. Nine (17%) participants had <90% of the liver visualised on US, compared with only 1 (2%) participant with AMRI, p < 0.0001. Obesity was a strong and independent predictor for severe visualisation limitation on US (OR 5.1, CI 1.1-23.1, p = 0.03), after adjustment for age, sex and ethnicity. CONCLUSION: More than one-third of participants with NAFLD cirrhosis had severe visualisation limitations on US for HCC screening, compared with one-sixth on AMRI. US adequacy should be reported in all clinical studies and when suboptimal then AMRI may be considered for HCC screening.


Asunto(s)
Carcinoma Hepatocelular , Neoplasias Hepáticas , Enfermedad del Hígado Graso no Alcohólico , Carcinoma Hepatocelular/diagnóstico por imagen , Carcinoma Hepatocelular/etiología , Medios de Contraste , Femenino , Humanos , Cirrosis Hepática/diagnóstico , Cirrosis Hepática/diagnóstico por imagen , Neoplasias Hepáticas/diagnóstico por imagen , Neoplasias Hepáticas/etiología , Imagen por Resonancia Magnética/métodos , Masculino , Persona de Mediana Edad , Enfermedad del Hígado Graso no Alcohólico/diagnóstico , Enfermedad del Hígado Graso no Alcohólico/diagnóstico por imagen , Estudios Prospectivos , Estudios Retrospectivos
12.
Radiol Case Rep ; 16(6): 1343-1347, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33897926

RESUMEN

Mature cystic teratomas are rare neoplasms composed of tissues from at least two of the germ layers. In the adult male pelvis, these tumors are exceptionally rare; only a small number of cases have been reported in the literature. We describe the case of a 76-year-old male with an extensive mature cystic teratoma in the rectovesical space, perineum, scrotum, and gluteal folds. This was misdiagnosed and managed as a chronic prostate abscess for six years. Few cases in the literature have reported mature cystic teratomas presenting as abscesses in male patients, and none in the male pelvis. This presentation should prompt physicians to consider the diagnosis of teratoma when managing similar cases, especially if cultures are negative and the symptoms recur despite treatment.

13.
Neuroimage ; 49(3): 2311-7, 2010 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-19854278

RESUMEN

Although the blood oxygenation level dependent (BOLD) signal used in most functional magnetic resonance imaging (fMRI) studies has been shown to exhibit nonlinear characteristics, most analyses assume that the BOLD signal responds in a linear fashion to stimulus. This assumption of linearity can lead to errors in the estimation of the BOLD response, especially for rapid event-related fMRI studies. In this study, we used a rapid event-related design and Volterra kernel analysis to assess the effect of a 200 mg oral dose of caffeine on the linearity of the visual BOLD response. The caffeine dose significantly (p<0.02) increased the linearity of the BOLD response in a sample of 11 healthy volunteers studied on a 3 T MRI system. In addition, the agreement between nonlinear and linear estimates of the hemodynamic response function was significantly increased (p=0.013) with the caffeine dose. These findings indicate that differences in caffeine usage should be considered as a potential source of bias in the analysis of rapid event-related fMRI studies.


Asunto(s)
Mapeo Encefálico , Encéfalo/efectos de los fármacos , Cafeína/farmacología , Estimulantes del Sistema Nervioso Central/farmacología , Circulación Cerebrovascular/efectos de los fármacos , Imagen por Resonancia Magnética , Adulto , Encéfalo/irrigación sanguínea , Humanos , Interpretación de Imagen Asistida por Computador , Adulto Joven
14.
Artículo en Inglés | MEDLINE | ID: mdl-33367272

RESUMEN

BACKGROUND: We theoretically derived a new quantitative metric reflecting the product of T1 signal intensity and contrast media concentration (T1C) using first principles for the signal provided by the gradient echo sequence. This metric can be used with conventional gadolinium contrast-enhanced magnetic resonance imaging (CE-MRI) exams. We used this metric to test our hypothesis that gadolinium enhancement changes with pancreatic ductal adenocarcinoma (PDA) treatment response, and that this metric may differentiate responders from non-responders. METHODS: Out of 264 initially identified patients, a final total of 35 patients with PDA were included in a retrospective study of responders (n=24) and non-responders (n=11), which used changes in cancer antigen 19-9 (CA 19-9) and tumor size as reference standards. T1C was computed for the pancreatic mass in the arterial, portal venous, and delayed phases in pre-treatment and post-treatment MRIs. Changes in measurements and correlations with treatment response were assessed by repeated measures analysis of variance and paired t-tests. RESULTS: In the treatment responder group, T1C significantly increased in the arterial, portal venous, and delayed phases (P=7.57e-5, P=3.25e-4, P=1.75e-4). In the non-responder group, T1C did not significantly change in any phase (P>0.58). Post-treatment T1C significantly differed between responders and non-responders (P=0.044) by repeated measures analysis of variance. CONCLUSIONS: T1C significantly increases in all phases of CE-MRI in responders to treatment, but does not change in non-responders. T1C correlates with treatment response, can be computed from clinical MRI exams, and may be useful as an additional metric to stratify patients undergoing treatment.

15.
Neuroimage ; 45(2): 420-30, 2009 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-19111622

RESUMEN

In the application of hypercapnic normalization to functional magnetic resonance imaging (fMRI) studies, the blood oxygenation level dependent (BOLD) response to a functional stimulus is typically divided by the BOLD response to a hypercapnic challenge. While some prior studies have shown that hypercapnic normalization can reduce inter-subject BOLD variability, other studies have found an increase in inter-subject variability. In this study we used measures of baseline cerebral blood flow (CBF) and the functional BOLD and CBF responses to both visual stimuli and hypercapnia to assess the effect of hypercapnic normalization on inter-subject variability. We found that the functional and hypercapnic BOLD and CBF responses all exhibited a significant inverse dependence on baseline CBF. In contrast, the maximum BOLD response was independent of baseline CBF and was not a major source of inter-subject BOLD variability. Division of the functional BOLD response by the hypercapnic BOLD response increased inter-subject variability in the normalized responses as compared to the original responses, reflecting the presence of a systematic bias term that was inversely dependent on the hypercapnic BOLD response. This systematic bias resulted from a positive intercept term in the linear relationship between the functional and hypercapnic BOLD responses. This positive intercept term reflected a steeper inverse dependence of the hypercapnic CBF response on baseline CBF, as compared to the functional CBF response. In contrast to the results obtained with normalization based on division, normalized responses obtained by using the hypercapnic BOLD response as a covariate were unaffected by the systematic bias and exhibited reduced inter-subject variability. The findings of this study indicate that the positive intercept in the linear relationship between functional and hypercapnic BOLD responses should be carefully considered in the hypercapnic normalization of BOLD fMRI data.


Asunto(s)
Encéfalo/metabolismo , Encéfalo/patología , Hipercapnia/metabolismo , Hipercapnia/patología , Imagen por Resonancia Magnética/métodos , Oxígeno/metabolismo , Adulto , Femenino , Humanos , Masculino , Reproducibilidad de los Resultados , Sensibilidad y Especificidad
16.
Neuroimage ; 46(1): 56-63, 2009 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-19457356

RESUMEN

In resting-state functional magnetic resonance imaging (fMRI), correlations between spontaneous low-frequency fluctuations in the blood oxygenation level dependent (BOLD) signal are used to assess functional connectivity between different brain regions. Changes in resting-state BOLD connectivity measures are typically interpreted as changes in coherent neural activity across spatially distinct brain regions. However, this interpretation can be complicated by the complex dependence of the BOLD signal on both neural and vascular factors. For example, prior studies have shown that vasoactive agents that alter baseline cerebral blood flow, such as caffeine and carbon dioxide, can significantly alter the amplitude and dynamics of the task-related BOLD response. In this study, we examined the effect of caffeine (200 mg dose) on resting-state BOLD connectivity in the motor cortex across a sample of healthy young subjects (N=9). We found that caffeine significantly (p<0.05) reduced measures of resting-state BOLD connectivity in the motor cortex. Baseline cerebral blood flow and spectral energy in the low-frequency BOLD fluctuations were also significantly decreased by caffeine. These results suggest that caffeine usage should be carefully considered in the design and interpretation of resting-state BOLD fMRI studies.


Asunto(s)
Cafeína/farmacología , Estimulantes del Sistema Nervioso Central/farmacología , Imagen por Resonancia Magnética , Corteza Motora/efectos de los fármacos , Vías Nerviosas/efectos de los fármacos , Adulto , Circulación Cerebrovascular/efectos de los fármacos , Femenino , Humanos , Interpretación de Imagen Asistida por Computador , Masculino , Corteza Motora/irrigación sanguínea , Descanso
17.
Cancer Immunol Res ; 7(9): 1396-1400, 2019 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-31383651

RESUMEN

High-grade malignant peripheral nerve sheath tumors (MPNST) have a poor prognosis with limited responsiveness to systemic therapy. We document a case of a complete metabolic response to pembrolizumab monotherapy in metastatic disease. Tumor molecular profiling identified programmed-death ligand-1 (PD-L1) positivity. This characteristic provided a rationale for immune-checkpoint therapy. Treatment with pembrolizumab resulted in a complete metabolic response after four cycles of therapy. Patients with PD-L1-positive, metastatic MPNST may be candidates for immune-checkpoint therapy, which may produce a durable complete remission. Future study of anti-PD-1/PD-L1 therapy is warranted.


Asunto(s)
Antineoplásicos Inmunológicos/uso terapéutico , Metabolismo Energético/efectos de los fármacos , Neoplasias de la Vaina del Nervio/tratamiento farmacológico , Neoplasias de la Vaina del Nervio/metabolismo , Receptor de Muerte Celular Programada 1/antagonistas & inhibidores , Antineoplásicos Inmunológicos/farmacología , Biopsia , Perfilación de la Expresión Génica , Humanos , Masculino , Estadificación de Neoplasias , Neoplasias de la Vaina del Nervio/diagnóstico , Tomografía Computarizada por Tomografía de Emisión de Positrones , Tomografía Computarizada por Rayos X , Resultado del Tratamiento , Adulto Joven
18.
Neuroimage ; 42(1): 296-305, 2008 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-18514545

RESUMEN

Measures of the spatial extent of functional activation are important for a number of functional magnetic resonance imaging (fMRI) applications, such as pre-surgical planning and longitudinal tracking of changes in brain activation with disease progression and drug treatment. The interpretation of the data from these applications can be complicated by inter-subject or inter-session variability in the measured fMRI signals. Prior studies have shown that modulation of baseline cerebral blood flow (CBF) can directly alter the functional CBF and blood oxygenation level dependent (BOLD) responses, suggesting that the spatial extents of functional activation maps based on these signals may also depend on baseline CBF. In this study, we used a caffeine dose (200 mg) to decrease baseline CBF and found significant (p<0.05) reductions in both the CBF activation extent and contrast-to-noise ratio (CNR) but no significant changes in the BOLD activation extent and CNR. In contrast, caffeine significantly changed the temporal dynamics of the BOLD response but not the CBF response. The decreases in the CBF activation extent and CNR were consistent with a significant caffeine-induced decrease in the absolute CBF change accompanied by no significant change in the residual noise. Measures of baseline CBF also accounted for a significant portion of the inter-subject variability in the CBF activation map area and CNR. Factors that can modulate baseline CBF, such as age, medication, and disease, should therefore be carefully considered in the interpretation of studies that use functional CBF activation maps.


Asunto(s)
Encéfalo/fisiología , Cafeína/administración & dosificación , Circulación Cerebrovascular/fisiología , Imagen por Resonancia Magnética/métodos , Consumo de Oxígeno/fisiología , Oxígeno/sangre , Adulto , Encéfalo/efectos de los fármacos , Circulación Cerebrovascular/efectos de los fármacos , Femenino , Humanos , Masculino , Consumo de Oxígeno/efectos de los fármacos
19.
Case Rep Oncol Med ; 2018: 7127048, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-29686913

RESUMEN

The low prevalence rate and limited literature on eccrine carcinoma (EC) pose a challenge to properly diagnosing and treating this rare malignancy. EC lesions tend to present similarly to other cutaneous neoplasms and dermatitis-like conditions. Efficacious treatment guidelines have not been established for patients diagnosed with EC, and few treatment regimens have demonstrated clinical benefit. Due to the high metastatic potential of EC, recognizing the clinical presentation, properly diagnosing, and utilizing beneficial treatment options are important for managing this disease. We report a case of a 66-year-old female who presented with lesions that her primary care provider misdiagnosed as basal cell carcinoma. The disease responded poorly to taxane- and platinum-based chemotherapies as well as an isolated limb perfusion of an alkylating agent. However, continuous dosing of oral capecitabine achieved an 18-month period of progression free survival (PFS) and ameliorated quality of life. We wish to highlight this rare disease and discuss presentation, diagnosis, and management as it is most often misdiagnosed leading to advanced metastatic disease when patients present to the oncologist. In addition, it is crucial to study and report potentially efficacious regimens considering the lack of clinical trials in this disease.

20.
Abdom Radiol (NY) ; 42(3): 935-950, 2017 03.
Artículo en Inglés | MEDLINE | ID: mdl-27933478

RESUMEN

Pelvic inflammatory disease (PID) is an ascending infection of the female genital tract caused by the spread of bacteria from the vagina to the pelvic reproductive organs and occasionally the peritoneum. The most common causative organisms are sexually transmitted. PID is a significant source of morbidity among reproductive age women both as a cause of abdominal pain and as a common cause of infertility. Its clinical presentation is often nonspecific, and the correct diagnosis may first come to light based on the results of imaging studies. MRI is well suited for the evaluation of PID and its complications due to its superior soft tissue contrast and high sensitivity for inflammation. MRI findings in acute PID include cervicitis, endometritis, salpingitis/oophoritis, and inflammation in the pelvic soft tissues. Acute complications include pyosalpinx, tuboovarian abscess, peritonitis, and perihepatitis. Hydrosalpinx, pelvic inclusion cysts and ureteral obstruction may develop as chronic sequela of PID. The pathophysiology, classification, treatment, and prognosis of PID are reviewed, followed by case examples of the appearance of acute and subclinical PID on MR images.


Asunto(s)
Imagen por Resonancia Magnética/métodos , Enfermedad Inflamatoria Pélvica/diagnóstico por imagen , Femenino , Humanos
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