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2.
PLoS One ; 15(2): e0228110, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32049969

RESUMO

PURPOSE: To evaluate the accuracy of a low-dose first-pass analysis (FPA) CT pulmonary perfusion technique in comparison to fluorescent microsphere measurement as the reference standard. METHOD: The first-pass analysis CT perfusion technique was validated in six swine (41.7 ± 10.2 kg) for a total of 39 successful perfusion measurements. Different perfusion conditions were generated in each animal using serial balloon occlusions in the pulmonary artery. For each occlusion, over 20 contrast-enhanced CT images were acquired within one breath (320 x 0.5mm collimation, 100kVp, 200mA or 400mA, 350ms gantry rotation time). All volume scans were used for maximum slope model (MSM) perfusion measurement, but only two volume scans were used for the FPA measurement. Both MSM and FPA perfusion measurements were then compared to the reference fluorescent microsphere measurements. RESULTS: The mean lung perfusion of MSM, FPA, and microsphere measurements were 6.21 ± 3.08 (p = 0.008), 6.59 ± 3.41 (p = 0.44) and 6.68 ± 3.89 ml/min/g, respectively. The MSM (PMSM) and FPA (PFPA) perfusion measurements were related to the corresponding reference microsphere measurement (PMIC) by PMSM = 0.51PMIC + 2.78 (r = 0.64) and PFPA = 0.79PMIC + 1.32 (r = 0.90). The root-mean-square-error for the MSM and FPA techniques were 3.09 and 1.72 ml/min/g, respectively. The root-mean-square-deviation for the MSM and FPA techniques were 2.38 and 1.50 ml/min/g, respectively. The CT dose index for MSM and FPA techniques were 138.7 and 8.4mGy, respectively. CONCLUSIONS: The first-pass analysis technique can accurately measure regional pulmonary perfusion and has the potential to reduce the radiation dose associated with dynamic CT perfusion for assessment of pulmonary disease.


Assuntos
Pulmão/irrigação sanguínea , Pulmão/diagnóstico por imagem , Imagem de Perfusão/métodos , Tomografia Computadorizada por Raios X/métodos , Animais , Doses de Radiação , Suínos
3.
PLoS One ; 15(1): e0227747, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31978097

RESUMO

We developed a visual ranking system by combining the parenchymal perfusion deficits (PPD) and hyperintense vessel signals (HVS) on arterial spin labeling (ASL) imaging. This study aimed to assess the performance of this ranking system by correlating with subtypes classified based on dynamic susceptibility contrast (DSC) imaging for evaluating the perfusion disturbance observed in patients with ischemic stroke. 32 patients with acute or subacute infarcts detected by DSC imaging were reviewed. Each patient's brain was divided into 12 areas. ASL ranks were defined by the presence (+) or absence (-) of PPD/HVS as follows; I:-/-, II:-/+, III: +/+, and IV: +/-. DSC imaging findings were categorized based on cerebral blood flow (CBF) and time to peak (TTP) as normal (normal CBF/TTP), mismatched (normal CBF/delayed TTP), and matched (decreased CBF/delayed TTP). Two reviewers rated perfusion abnormalities in the total of 384 areas. The four ASL ranks correlated well with the DSC subtypes (Spearman's r = 0.82). The performance of ASL ranking system was excellent as indicated by the area under the curve value of 0.94 using either matched or mismatched DSC subtype as the gold standard and 0.97 using only the matched DSC subtype as the gold standard. The two methods were in good-to-excellent agreement (maximum κ-values, 0.86). Inter-observer agreement was excellent (κ-value, 0.98). Although the number of patients was small and the number of dropouts was high, our proposed, ASL-based visual ranking system represented by PPD and HVS provides good, graded estimates of perfusion disturbance that agree well with those obtained by DSC perfusion imaging.


Assuntos
Infarto Encefálico/diagnóstico , Encéfalo/diagnóstico por imagem , Artérias Cerebrais/fisiopatologia , Angiografia por Ressonância Magnética/métodos , Imagem de Perfusão/métodos , Idoso , Idoso de 80 Anos ou mais , Encéfalo/irrigação sanguínea , Infarto Encefálico/fisiopatologia , Artérias Cerebrais/diagnóstico por imagem , Volume Sanguíneo Cerebral/fisiologia , Circulação Cerebrovascular/fisiologia , Estudos de Viabilidade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Marcadores de Spin
6.
J Stroke Cerebrovasc Dis ; 29(2): 104467, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31767525

RESUMO

BACKGROUND AND AIM: Although fluid-attenuated inversion recovery vascular hyperintensities may be frequently seen in acute large-artery ischemic stroke, reports on their prognostic utility had been conflicting due to lack of quantitative evaluation of the perfusion status based on the signal intensity. We hypothesized that greater hyperintensity represents more severe hypoperfusion. METHODS: Overall, 27 patients with acute occlusion of the proximal middle cerebral artery were divided into 2 groups, based on their signal intensity in the insular segment of middle cerebral artery on the affected side, relative to that of the insular cortex: the low signal intensity group (hypo- or isointense signals, n = 12) and the high signal intensity group (hyperintense signals, n = 15). Using dynamic susceptibility contrast magnetic resonance imaging, we assessed the time of the maximum value of the residue function and mean transit time, in the entire middle cerebral artery cortical area and diffusion-weighted imaging-Alberta Stroke Program Early Computed Tomography Score regions, including the corona radiata. RESULTS: The high signal intensity group had significantly longer time of the maximum value of the residue function in all the diffusion-weighted imaging-Alberta Stroke Program Early Computed Tomography Score regions, except the M3 and M6 regions, and significantly longer mean transit time in the M1 and M4 regions. CONCLUSIONS: Quantitative analysis of the perfusion parameters revealed more severely compromised and widely disturbed perfusion status in the high signal intensity group than in the low signal intensity group.


Assuntos
Circulação Cerebrovascular , Imagem de Difusão por Ressonância Magnética , Infarto da Artéria Cerebral Média/diagnóstico por imagem , Angiografia por Ressonância Magnética , Artéria Cerebral Média/diagnóstico por imagem , Imagem de Perfusão/métodos , Idoso , Idoso de 80 Anos ou mais , Velocidade do Fluxo Sanguíneo , Feminino , Humanos , Infarto da Artéria Cerebral Média/fisiopatologia , Masculino , Artéria Cerebral Média/fisiopatologia , Valor Preditivo dos Testes , Estudos Retrospectivos , Índice de Gravidade de Doença
7.
J Comput Assist Tomogr ; 44(1): 75-77, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31804241

RESUMO

Computed tomography perfusion (CTP) is increasingly used to determine treatment eligibility for acute ischemic stroke patients. Automated postprocessing of raw CTP data is routinely used, but it can fail. In reviewing 176 consecutive acute ischemic stroke patients, failures occurred in 20 patients (11%) during automated postprocessing by the RAPID software. Failures were caused by motion (n = 11, 73%), streak artifacts (n = 2, 13%), and poor contrast bolus arrival (n = 2, 13%). Stroke physicians should review CTP results with care before they are being integrated in their decision-making process.


Assuntos
Isquemia Encefálica/diagnóstico por imagem , Processamento Eletrônico de Dados/métodos , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Acidente Vascular Cerebral/diagnóstico por imagem , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Imagem de Perfusão/métodos , Fatores de Risco , Sensibilidade e Especificidade , Software , Tomografia Computadorizada por Raios X
8.
Br J Radiol ; 93(1106): 20190790, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31778314

RESUMO

OBJECTIVE: To assess metastatic involvement of perigastric lymph nodes (PLNs) in patients with T1 gastric cancer by using CT perfusion imaging (CTPI). METHODS: A total of 82 annotated PLNs of 33 patients with T1 gastric cancer confirmed by endoscopic ultrasonography underwent CTPI and portal phase CT scan before operation. The scan data were post-processed to acquire perfusion maps and calculate perfusion parameters including blood flow (BF) and permeability surface (PS). A radiologist measured the short axis diameters and perfusion parameters of PLNs. According to the post-operative pathology result, PLNs were divided into two groups: metastatic and inflammatory LNs. Perfusion parameters values and the size of PLNs between two groups were respectively compared statistically by t-test, and a receiver operating characteristic curve analysis was used to determine the optimal diagnostic cut-off value with sensitivity, specificity and area under the curve. RESULTS: Examined 82 PLNs were metastatic in 45 (54.9%) and inflammatory in 37 (45.1%). The mean values of perfusion parameters and the short axis diameters in metastatic and inflammatory PLNs, respectively, were BF of 97.48 vs 81.21 ml/100 mg /min (p < 0.001), PS of 45.11 vs 36.80 ml/100 mg /min (p < 0.001), and the size of 1.51 cm vs 1.29 cm (p = 0.059). The sensitivity of 84.4%, specificity of 67.6% and area under the curve of 0.826 for BF with cut-off value of 88.89 ml/100 mg /min for differentiating metastatic from inflammatory nodes were higher than those of PS or the size of PLNs (p < 0.001). CONCLUSION: CT perfusion parameters values were different between metastatic and inflammatory PLNs in T1 gastric cancer. BF value may be the most reliable diagnostic marker of metastatic PLNs, and it is helpful for clinicians to choose treatment modality or management plan in T1 gastric cancer patients. ADVANCES IN KNOWLEDGE: CTPI gives information on vascularization of LNs.BF value might be a more effective marker than PS or the size of LNs for differentiating metastatic from inflammatory LNs in patients with T1 gastric cancer.


Assuntos
Adenocarcinoma/diagnóstico por imagem , Junção Esofagogástrica/diagnóstico por imagem , Linfonodos/diagnóstico por imagem , Neoplasias Gástricas/diagnóstico por imagem , Adulto , Idoso , Feminino , Humanos , Metástase Linfática , Masculino , Pessoa de Meia-Idade , Imagem de Perfusão/métodos , Curva ROC , Tomografia Computadorizada por Raios X/métodos
9.
Eur J Radiol ; 122: 108753, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31794892

RESUMO

PURPOSE: To evaluate the diagnostic efficacy in differentiating metastatic from inflammatory perigastric lymph nodes (LNs) in patients with gastric cancer by using CT perfusion imaging (CTPI). METHOD: A total of 115 annotated perigastric LNs of 50 patients with gastric cancer confirmed by pathology underwent CTPI scan before operation. The scan data were postprocessed to acquire perfusion maps and parameters including blood flow (BF) and permeability surface (PS). A radiologist measured the short and long axis diameters, the short/long axis ratio and perfusion parameters of LNs. According to the post-operative pathology result, LNs were divided into two groups: metastatic and inflammatory nodes. Perfusion parameters and the size of LNs between two groups were respectively compared statistically, and a receiver-operating characteristic (ROC) curve analysis was used to determine the optimal diagnostic cutoff value with sensitivity, specificity and area under the curve (AUC). RESULTS: The mean values of perfusion parameters and the short/long axis diameters ratio in metastatic and inflammatory LNs, respectively, were BF of 91.64 vs. 79.35 ml/100 mg /min (p <  0.01), PS of 43.42 vs. 35.92 ml/100 mg /min (p <  0.01), and the size ratio of 0.75 vs. 0.68 (p <  0.01). The sensitivity of 85.3%, specificity of 66.0 % and AUC of 0.816 for BF with cutoff value of 80.76 ml/100 mg /min for differentiating metastatic from inflammatory nodes were higher than those of PS or the size of LNs (p < 0.05). CONCLUSIONS: BF may be a reliable diagnostic marker of metastatic perigastric LNs in gastric cancer.


Assuntos
Linfonodos/diagnóstico por imagem , Neoplasias Gástricas/diagnóstico por imagem , Adulto , Idoso , Área Sob a Curva , Feminino , Humanos , Metástase Linfática , Masculino , Pessoa de Meia-Idade , Imagem de Perfusão/métodos , Estudos Prospectivos , Curva ROC , Cintilografia , Sensibilidade e Especificidade , Tomografia Computadorizada por Raios X/métodos
10.
J Thorac Cardiovasc Surg ; 159(3): 798-810.e1, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31078313

RESUMO

OBJECTIVE: The aim of this study was to compare aortic flow patterns in patients after David valve-sparing aortic root replacement with physiologically shaped sinus prostheses or conventional tube grafts in healthy volunteers. METHODS: Twelve patients with sinus prostheses (55 ± 15 years), 6 patients with tube grafts (58 ± 12 years), 12 age-matched, healthy volunteers (55 ± 6 years), and 6 young, healthy volunteers (25 ± 3 years) were examined with time-resolved 3-dimensional magnetic resonance phase contrast imaging (4D Flow MRI). Primary and secondary helical, as well as vortical flow patterns, were evaluated. Aortic arch anatomy as a flow influencing factor was determined. RESULTS: Compared with volunteers, both sinus prostheses and tube grafts developed more than 4 times as many secondary flow patterns in the ascending aorta (sinus prostheses n = 1.6 ± 0.8; tube grafts n = 1.3 ± 0.6; age-matched, healthy volunteers n = 0.3 ± 0.5; young, healthy volunteers n = 0; P ≤ .012) associated with a kinking of the prosthesis itself or at its distal anastomosis. As opposed to round aortic arches in volunteers (n = 16/18), cubic or gothic-shaped arches predominated in patients (n = 16/18, P < .001). In all but 3 volunteers, 2 counter-rotating helices were confirmed in the ascending aorta and were defined as a primary flow pattern. This primary flow pattern did not develop in patients who underwent valve-sparing aortic root replacement. CONCLUSIONS: In patients after valve-sparing aortic root replacement, there was an increased number of secondary flow patterns in the ascending aorta. This seems to be related to surgically altered aortic geometry with kinking. Because flow alterations are known to affect wall shear stress, there seems to be an increased risk for vessel wall remodeling. Compared with previous 4D Flow MRI studies, primary flow patterns in the ascending aorta in healthy subjects were confirmed to be more complex. This underlines the importance of thorough examination of 4D Flow MRI data.


Assuntos
Aorta/cirurgia , Aneurisma Aórtico/cirurgia , Implante de Prótese Vascular/instrumentação , Prótese Vascular , Hemodinâmica , Imageamento Tridimensional , Angiografia por Ressonância Magnética , Imagem de Perfusão/métodos , Adulto , Idoso , Aorta/diagnóstico por imagem , Aorta/fisiopatologia , Aneurisma Aórtico/diagnóstico por imagem , Aneurisma Aórtico/fisiopatologia , Valva Aórtica/diagnóstico por imagem , Valva Aórtica/fisiopatologia , Velocidade do Fluxo Sanguíneo , Implante de Prótese Vascular/efeitos adversos , Estudos de Casos e Controles , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Modelos Cardiovasculares , Modelagem Computacional Específica para o Paciente , Projetos Piloto , Valor Preditivo dos Testes , Desenho de Prótese , Falha de Prótese , Fluxo Sanguíneo Regional , Fatores de Tempo , Resultado do Tratamento
11.
Stroke ; 51(2): 489-497, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31884904

RESUMO

Background and Purpose- Selection of patients with acute ischemic stroke for endovascular treatment generally relies on dynamic susceptibility contrast magnetic resonance imaging or computed tomography perfusion. Dynamic susceptibility contrast magnetic resonance imaging requires injection of contrast, whereas computed tomography perfusion requires high doses of ionizing radiation. The purpose of this work was to develop and evaluate a deep learning (DL)-based algorithm for assisting the selection of suitable patients with acute ischemic stroke for endovascular treatment based on 3-dimensional pseudo-continuous arterial spin labeling (pCASL). Methods- A total of 167 image sets of 3-dimensional pCASL data from 137 patients with acute ischemic stroke scanned on 1.5T and 3.0T Siemens MR systems were included for neural network training. The concurrently acquired dynamic susceptibility contrast magnetic resonance imaging was used to produce labels of hypoperfused brain regions, analyzed using commercial software. The DL and 6 machine learning (ML) algorithms were trained with 10-fold cross-validation. The eligibility for endovascular treatment was determined retrospectively based on the criteria of perfusion/diffusion mismatch in the DEFUSE 3 trial (Endovascular Therapy Following Imaging Evaluation for Ischemic Stroke). The trained DL algorithm was further applied on twelve 3-dimensional pCASL data sets acquired on 1.5T and 3T General Electric MR systems, without fine-tuning of parameters. Results- The DL algorithm can predict the dynamic susceptibility contrast-defined hypoperfusion region in pCASL with a voxel-wise area under the curve of 0.958, while the 6 ML algorithms ranged from 0.897 to 0.933. For retrospective determination for subject-level endovascular treatment eligibility, the DL algorithm achieved an accuracy of 92%, with a sensitivity of 0.89 and specificity of 0.95. When applied to the GE pCASL data, the DL algorithm achieved a voxel-wise area under the curve of 0.94 and a subject-level accuracy of 92% for endovascular treatment eligibility. Conclusions- pCASL perfusion magnetic resonance imaging in conjunction with the DL algorithm provides a promising approach for assisting decision-making for endovascular treatment in patients with acute ischemic stroke.


Assuntos
Isquemia Encefálica/diagnóstico , Aprendizado Profundo , Imagem de Perfusão , Acidente Vascular Cerebral/diagnóstico , Circulação Cerebrovascular/fisiologia , Imagem de Difusão por Ressonância Magnética/métodos , Humanos , Angiografia por Ressonância Magnética/métodos , Imagem de Perfusão/métodos , Estudos Retrospectivos , Marcadores de Spin
12.
PLoS One ; 14(12): e0226304, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31826009

RESUMO

BACKGROUND: Recently, porous acupuncture (PA), which is anodized to increase its surface area for higher stimulation intensity, was developed and showed significantly improved therapeutic effects with more comfort as compared with original acupuncture (OA) in vivo. However, the impact of PA on the change of local blood flow as well as its efficacy and acceptability has not yet been confirmed in a clinical trial. In a randomized, controlled crossover clinical trial, we investigated the effects of PA on the change in local blood flow using laser Doppler perfusion imaging and considered the sensation of pain intensity and discomfort severity using a visual analogue scale (VAS) to explore its physiological impact and the possibility of PA in clinical use. METHODS: Twenty-one healthy participants were randomly treated with PA or OA on one side of Zusanli (ST36) and each participant served as his or her own control. Baseline local blood flow and galvanic skin response (GSR) were obtained for 5 min and acupuncture interventions were subsequently performed. Next, local blood flow and GSR were subsequently obtained for 10 min after insertion, 10 min after manipulation, and 5 min after the withdrawal of acupuncture. At the end of the experiment, participants were asked to indicate the sensation of pain intensity at each session of insertion, retention, manipulation, and withdrawal as well as the overall pain intensity and discomfort severity. RESULTS: PA significantly increased the local blood flow as compared with OA and there was no significant difference in GSR between patients treated with PA versus OA in each phase of insertion and manipulation. No significant difference in pain intensity or discomfort severity was found during manipulation, retention, or withdrawal of acupuncture. CONCLUSIONS: These results indicate that PA increases local blood flow, which can be closely related to the observed enhanced performance, without any associated discomfort or pain, suggesting its applicability in clinical practice.


Assuntos
Acupuntura/métodos , Nanoporos , Pele/diagnóstico por imagem , Adolescente , Adulto , Feminino , Resposta Galvânica da Pele , Voluntários Saudáveis , Humanos , Masculino , Pessoa de Meia-Idade , Dor/patologia , Medição da Dor , Imagem de Perfusão/métodos , Fluxo Sanguíneo Regional , Índice de Gravidade de Doença , Pele/irrigação sanguínea , Adulto Jovem
13.
Cerebrovasc Dis ; 48(3-6): 217-225, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31812964

RESUMO

OBJECTIVE: Superficial temporal artery (STA)-middle cerebral artery (MCA) anastomosis is a standard surgical procedure for adult patients with moyamoya disease (MMD) and plays a role in preventing ischemic and/or hemorrhagic stroke. Cerebral hyperperfusion (CHP) syndrome is a potential complication of this procedure that can result in deleterious outcomes, such as delayed intracerebral hemorrhage, but the exact threshold of the pathological increase in postoperative cerebral blood flow (CBF) is unclear. Thus, we analyzed local CBF in the acute stage after revascularization surgery for adult MMD to predict CHP syndrome under modern perioperative management. MATERIALS AND METHODS: Fifty-nine consecutive adult MMD patients, aged 17-66 years old (mean 43.1), underwent STA-MCA anastomosis with indirect pial synangiosis for 65 affected hemispheres. All patients were perioperatively managed by strict blood pressure control (systolic pressure of 110-130 mm Hg) to prevent CHP syndrome. Local CBF at the site of anastomosis was quantitatively measured using the autoradiographic method by N-isopropyl-p-[123I] iodoamphetamine single-photon emission computed tomography 1 and 7 days after surgery, in addition to the preoperative CBF value at the corresponding area. We defined CHP phenomenon as a local CBF increase over 150% compared to the preoperative value. Then, we investigated the correlation between local hemodynamic change and the development of CHP syndrome. RESULTS: After 65 surgeries, 5 patients developed CHP syndrome, including 2 patients with delayed intracerebral hemorrhage (3.0%), 1 with symptomatic subarachnoid hemorrhage (1.5%), and 2 with focal neurological deterioration without hemorrhage. The CBF increase ratio was significantly higher in patients with CHP syndrome (270.7%) than in patients without CHP syndrome (135.2%, p = 0.003). Based on receiver operating characteristic analysis, the cutoff value for the pathological postoperative CBF increase ratio was 184.5% for CHP syndrome (sensitivity = 83.3%, specificity =  94.2%, area under the curve [AUC] value  =  0.825) and 241.3% for hemorrhagic CHP syndrome (sensitivity =  75.0%, specificity =  97.2%, AUC value  =  0.742). CONCLUSION: Quantitative measurement of the local CBF value in the early postoperative period provides essential information to predict CHP syndrome after STA-MCA anastomosis in patients with adult MMD. The pathological threshold of hemorrhagic CHP syndrome was as high as 241.3% by the local CBF increase ratio, but 2 patients (3.0%) developed delayed intracerebral hemorrhage in this series that were managed following the intensive perioperative management protocol. Thus, we recommend routine CBF measurement in the acute stage after direct revascularization surgery for adult MMD and satisfactory blood pressure control to avoid the deleterious effects of CHP.


Assuntos
Revascularização Cerebral/efeitos adversos , Circulação Cerebrovascular , Artéria Cerebral Média/cirurgia , Doença de Moyamoya/cirurgia , Imagem de Perfusão/métodos , Complicações Pós-Operatórias/diagnóstico por imagem , Artérias Temporais/cirurgia , Tomografia Computadorizada de Emissão de Fóton Único , Adolescente , Adulto , Idoso , Anastomose Cirúrgica , Velocidade do Fluxo Sanguíneo , Diagnóstico Precoce , Feminino , Humanos , Iofetamina/administração & dosagem , Masculino , Pessoa de Meia-Idade , Artéria Cerebral Média/diagnóstico por imagem , Artéria Cerebral Média/fisiopatologia , Doença de Moyamoya/diagnóstico por imagem , Doença de Moyamoya/fisiopatologia , Complicações Pós-Operatórias/etiologia , Complicações Pós-Operatórias/fisiopatologia , Valor Preditivo dos Testes , Compostos Radiofarmacêuticos/administração & dosagem , Fatores de Risco , Artérias Temporais/diagnóstico por imagem , Artérias Temporais/fisiopatologia , Fatores de Tempo , Resultado do Tratamento , Adulto Jovem
14.
Med Sci Monit ; 25: 10029-10035, 2019 Dec 27.
Artigo em Inglês | MEDLINE | ID: mdl-31879414

RESUMO

BACKGROUND This feasibility study aimed to compare real-time two-dimensional contrast-enhanced ultrasound (2D-CEUS) and three-dimensional contrast-enhanced ultrasound (3D-CEUS) to quantify flow in an in vitro model. MATERIAL AND METHODS Five polyvinyl chloride (PVC) tubes were used for the perfusion models and used SonoVue ultrasound contrast agent with a perfusion volume ratio of 1: 2: 4: 8: 16. The contrast was injected at a constant speed to compare the raw quantitative data of 2D-CEUS and 3D-CEUS at angles of 0°, 45°, and 90°. The coefficient of variation (CV) of the peak intensity (PI) in the model were compared and the correlations between weighted PI and perfusion volume were analyzed. RESULTS In the three angles used, real-time 3D-CEUS resulted in a more comprehensive view of the spatial relationships in the perfusion model. Using real-time 2D-CEUS, the mean CV was 0.92±0.36, and the mean CV in the real-time 3D-CEUS model was significantly less at 0.48±0.32 (p<0.001). Quantitative 3D-CEUS parameters showed a good correlation with those of 2D-CEUS with an r-value of 0.93 (p=0.02). The r-value of weighted PI and the perfusion ratio using 2D-CEUS was 0.66 (p=0.23) compared with values in 3D-CEUS of 0.84 (p=0.08). CONCLUSIONS The combination of real-time 3D-CEUS and quantitative analysis identified the spatial distribution of the changes in angle in the model, which was less influenced by sectional planes, and was more representative of the perfusion volume when compared with 2D-CEUS. Quantitative real-time 3D-CEUS requires in vivo studies to evaluate the potential role in the clinical evaluation of vascular perfusion of malignant tumors.


Assuntos
Análise de Injeção de Fluxo/métodos , Imagem de Perfusão/métodos , Ultrassonografia/métodos , Meios de Contraste , Estudos de Viabilidade , Aumento da Imagem/métodos , Interpretação de Imagem Assistida por Computador/métodos , Imageamento Tridimensional/métodos , Modelos Anatômicos , Modelos Estruturais , Perfusão/métodos , Fosfolipídeos , Hexafluoreto de Enxofre
15.
J Pak Med Assoc ; 69(12): 1924-1926, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31853132

RESUMO

High grade brain tumours are treated with surgery, chemotherapy and radiation therapy and despite such aggressive treatment, can recur in a short span of time. MRI scan has been the conventional diagnostic modality to diagnose recurrence, although at times it becomes difficult for the neuroradiologists to differentiate between tumour recurrence and radiation necrosis. Herein lies the emergent need to explore the efficacy of functional imaging to assist in this diagnostic challenge. Recent studies have sought to do so with promising implications, which we have attempted to summarize in this review.


Assuntos
Neoplasias Encefálicas/diagnóstico por imagem , Imagem por Ressonância Magnética/métodos , Recidiva Local de Neoplasia/diagnóstico por imagem , Imagem de Perfusão/métodos , Lesões por Radiação/diagnóstico por imagem , Encéfalo/diagnóstico por imagem , Encéfalo/patologia , Neoplasias Encefálicas/patologia , Diagnóstico Diferencial , Humanos , Necrose , Recidiva Local de Neoplasia/patologia , Lesões por Radiação/patologia
16.
PLoS One ; 14(12): e0225673, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31856177

RESUMO

PURPOSE: Advanced forms of prostate cancer (PCa) radiotherapy with either external beam therapy or brachytherapy delivery techniques aim for a focal boost and thus require accurate lesion localization and lesion segmentation for subsequent treatment planning. This study prospectively evaluated dynamic contrast-enhanced computed tomography (DCE-CT) for the detection of prostate cancer lesions in the peripheral zone (PZ) using qualitative and quantitative image analysis compared to multiparametric magnet resonance imaging (mpMRI) of the prostate. METHODS: With local ethics committee approval, 14 patients (mean age, 67 years; range, 57-78 years; PSA, mean 8.1 ng/ml; range, 3.5-26.0) underwent DCE-CT, as well as mpMRI of the prostate, including standard T2, diffusion-weighted imaging (DWI), and DCE-MRI sequences followed by transrectal in-bore MRI-guided prostate biopsy. Maximum intensity projections (MIP) and DCE-CT perfusion parameters (CTP) were compared between healthy and malignant tissue. Two radiologists independently rated image quality and the tumor lesion delineation quality of PCa using a five-point ordinal scale. MIP and CTP were compared using visual grading characteristics (VGC) and receiver operating characteristics (ROC)/area under the curve (AUC) analysis. RESULTS: The PCa detection rate ranged between 57 to 79% for the two readers for DCE-CT and was 92% for DCE-MRI. DCE-CT perfusion parameters in PCa tissue in the PZ were significantly different compared to regular prostate tissue and benign lesions. Image quality and lesion visibility were comparable between DCE-CT and DCE-MRI (VGC: AUC 0.612 and 0.651, p>0.05). CONCLUSION: Our preliminary results suggest that it is feasible to use DCE-CT for identification and visualization, and subsequent segmentation for focal radiotherapy approaches to PCa.


Assuntos
Tomografia Computadorizada Quadridimensional/métodos , Imagem de Perfusão/métodos , Neoplasias da Próstata/radioterapia , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia Guiada por Imagem/métodos , Idoso , Biópsia com Agulha de Grande Calibre , Meios de Contraste/administração & dosagem , Imagem de Difusão por Ressonância Magnética , Estudos de Viabilidade , Humanos , Biópsia Guiada por Imagem , Masculino , Pessoa de Meia-Idade , Gradação de Tumores , Estudo de Prova de Conceito , Estudos Prospectivos , Próstata/diagnóstico por imagem , Próstata/patologia , Neoplasias da Próstata/diagnóstico por imagem , Neoplasias da Próstata/patologia , Doses de Radiação
17.
J Stroke Cerebrovasc Dis ; 28(12): 104471, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31680033

RESUMO

INTRODUCTION: Despite the increasing national adoption of automated computed tomography perfusion (CTP) to select thrombectomy patients 6 hours after last known well, reliability issues have been anecdotally reported. Unreliable diagnostic tests add time and confusion to a process that requires efficiency. Our study aims to critically assess an automated CTP program in a contemporary cohort of patients presenting with large vessel occlusion (LVO) in the extended time window by evaluating the rate of unreliable automated CTP maps and whether this influences clinical outcomes. METHODS: A retrospective review of consecutive thrombectomy candidates undergoing CTP imaging in the extended time window was performed. All automated CTP maps using RAPID software (iSchemaView, Menlo Park, CA) were assessed for reliability. Clinical outcomes were compared between patients with and without reliable RAPID reports. RESULTS: Ninety-nine consecutive thrombectomy candidates underwent automated CTP imaging from February 2017 to December 2018. Of these, 78 (79%) had LVO determined by CT angiographyand were included in the study population. Automated CTP maps were unreliable in 13% of cases as a result of motion artifact (n = 3) and contrast bolus flow issues (n = 7). Heart failure was more frequent in patients with unreliable studies. Clinical outcomes did not significantly differ between patients with and without unreliable studies. CONCLUSIONS: Thirteen percent of CTP maps generated by automated software were unreliable, with an increased frequency among patients with heart failure. Given the rate of unreliable automated CTP maps, further studies are warranted to not only establish the true necessity of currently available CTP software, but also more reliable methods to select patients for thrombectomy presenting in the extended time window.


Assuntos
Artefatos , Isquemia Encefálica/diagnóstico por imagem , Circulação Cerebrovascular , Imagem de Perfusão/métodos , Interpretação de Imagem Radiográfica Assistida por Computador , Acidente Vascular Cerebral/diagnóstico por imagem , Tomografia Computadorizada por Raios X , Idoso , Automação , Isquemia Encefálica/fisiopatologia , Isquemia Encefálica/terapia , Tomada de Decisão Clínica , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Reprodutibilidade dos Testes , Estudos Retrospectivos , Software , Acidente Vascular Cerebral/fisiopatologia , Acidente Vascular Cerebral/terapia , Trombectomia , Fatores de Tempo
18.
Ulus Travma Acil Cerrahi Derg ; 25(6): 561-566, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31701496

RESUMO

BACKGROUND: Intra-abdominal hypertension (IAH) is a frequent cause of acute kidney injury (AKI) among critically ill patients who have risk factors. This study aimed to determine the relation between Abdominal Perfusion Pressure (APP) and AKI showed by the Doppler-based renal resistive index (RRI). METHODS: In this study, 38 patients older than 18 years old who received mechanical ventilation and had risk factors for the development of IAH were prospectively studied. All measurements and parameters were divided into two groups according to renal dysfunction (Group I: RRI <0.72 vs Group II: RRI >0.72). RESULTS: The mean IAPs were not significant between the groups, 11.5±6.9 mm Hg in Group I (n=35) and 13.5±5.8 in Group II (n=33), respectively. APPs were statistically higher in Group I (81.2±13.6) than Group II (66.4±9.5) (p<0.001). The AUC for the association between APP at RRI >0.72 was 0.802 (p<0.001), with the APP ≤72 mmHg having a sensitivity of the 76% (95% CI 58-89%) and a specificity of 71% (95% CI 54-85%). CONCLUSION: Our findings suggest that an APP with a threshold of ≤72 mmHg is associated with a significant increase in renal RRI, which may be predictive of worsening of renal perfusion.


Assuntos
Lesão Renal Aguda , Estado Terminal , Hipertensão Intra-Abdominal , Imagem de Perfusão/métodos , Ultrassonografia Doppler/métodos , Lesão Renal Aguda/diagnóstico por imagem , Lesão Renal Aguda/fisiopatologia , Adulto , Humanos , Hipertensão Intra-Abdominal/diagnóstico por imagem , Hipertensão Intra-Abdominal/fisiopatologia , Estudos Prospectivos
19.
Phys Med Biol ; 64(24): 245004, 2019 12 13.
Artigo em Inglês | MEDLINE | ID: mdl-31703216

RESUMO

Dedicated breast CT is a fully tomographic breast imaging modality with potential for various applications throughout breast cancer care. If implemented to perform dynamic contrast-enhanced (CE) imaging (4D breast CT), it could be useful to obtain functional information at high combined spatio-temporal resolution. Before developing a 4D dedicated breast CT system, a computer simulation method for breast CT perfusion imaging is proposed. The simulation uses previously developed patient-based 4D digital breast phantoms, and generates realistic images with the selected acquisition parameters, allowing to investigate the effect of different acquisition settings on image quality. The simulation pipeline includes all steps of the image generation process, from ray tracing and scatter map generation, to the addition of realistic resolution losses and noise models. The pipeline was validated against experimental measurements performed on physical phantoms with a dedicated breast CT system, in terms of average error compared to ground truth projections (6.0% ± 1.65%), Hounsfield unit (HU) values in a homogeneous phantom (acquired: -149 HU ± 2 HU; simulated: -140 HU ± 2 HU), signal-to-noise ratio (SNR) (average error 6.7% ± 4.2%), noise power spectra (NPS) (average error 4.3% ± 2.5%), modulation transfer function (MTF) (average error 8.4% ± 7.2%), and attenuation of different adipose/glandular equivalent mixtures (average error 6.9% ± 4.0%) and glandular plus iodinated contrast medium concentrations equivalent mixtures (average error of 9.1% ± 9.0%). 4D patient images were then simulated for different 4D digital breast phantoms at different air kerma levels to determine the effect of noise on the extracted tumor perfusion curves. In conclusion, the proposed pipeline could simulate images with a good level of realism, resulting in a tool that can be used for the design, development, and optimization of a 4D dedicated breast CT system.


Assuntos
Neoplasias da Mama/diagnóstico por imagem , Tomografia Computadorizada Quadridimensional/métodos , Imagem de Perfusão/métodos , Simulação por Computador , Feminino , Tomografia Computadorizada Quadridimensional/normas , Humanos , Imagem de Perfusão/normas , Imagens de Fantasmas , Razão Sinal-Ruído
20.
Neurol India ; 67(5): 1235-1239, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31744949

RESUMO

Background: It has been acknowledged that delayed cerebral ischemia (DCI) can be diagnosed by computed tomography perfusion (CTP) when it occurs following aneurysmal subarachnoid hemorrhage (aSAH); however, the clinical role of CTP in the prediction of DCI remains unclear. We performed a meta-analysis to investigate the role of CTP in the identification of patients at risk for DCI during the acute phase (<4 days) after aSAH. Materials and Methods: Relevant articles were systematically searched for analysis on PubMed, EMBASE, and Cochrane databases. The best CTP parameter or the definition of abnormal CTP scan result were collected, and the data with the greatest overall predictive value for DCI was extracted to assess the strength of association between a positive CTP result and an impending DCI. In addition, pooled estimates of sensitivity and specificity were determined. Results: Three relevant articles involving 128 patients were included in the analysis wherein DCI developed in 48 patients (37.5%). The pooled odds ratio was 32.15 (95% CI, 9.92-104.21), suggesting that the patients with a positive CTP test in the acute phase after aSAH were approximately 32 times as likely to develop DCI compared with those without aSAH. The pooled sensitivity and specificity of CTP for detecting impending DCI after aSAH was 65% (95% CI: 0.49-0.78) and 91% (95% CI: 0.83-0.96). Conclusions: CTP can detect abnormal brain perfusion before the occurrence of DCI. This may allow close monitoring and preemptive therapy for improvement in the prognosis in patients with aSAH.


Assuntos
Isquemia Encefálica/diagnóstico por imagem , Imagem de Perfusão/métodos , Hemorragia Subaracnóidea/complicações , Tomografia Computadorizada por Raios X/métodos , Isquemia Encefálica/etiologia , Humanos , Neuroimagem/métodos
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