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1.
J Vasc Interv Radiol ; 35(10): 1474-1480, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-38914160

RESUMO

PURPOSE: To evaluate the safety and effectiveness of magnetic resonance (MR) imaging-guided cryoablation of prostate cancer metastatic lymph nodes (LNs). MATERIALS AND METHODS: Fifty-two patients with prostate cancer who underwent MR imaging-guided LN ablation from September 2013 to June 2022 were retrospectively reviewed. Of these, 6 patients were excluded because adequate ablation margins (3-5 mm) could not be achieved secondary to adjacent structures. The remaining 46 patients (mean age, 70 years [SD ± 7]) underwent 55 MR imaging-guided cryoablation procedures of metastatic LNs (25 in the pelvic sidewall, 20 within the pelvic region, and 10 in the abdomen) with procedural intent of complete ablation. Locoregional tumor control (ie, technical success in the target LN) was evaluated on initial follow-up positron emission tomography (PET) scans at a mean of 4 months (SD ± 2). Preablation and postablation prostate-specific antigen (PSA) levels were recorded. Imaging follow-up continued until a median of 27.5 months (range: 3-108 months). RESULTS: Ninety-five percent (52/55) of treated LNs demonstrated no considerable activity on PET scans at initial follow-up at 4 months (SD ± 2). PSA decreased to an undetectable level of <0.1 ng/mL after cryoablation in 14 of 46 (30.4%) patients with corresponding lack of activity in 13 of 46 (28.2%) patients on continued PET imaging follow-up. Only 6 of 55 (10.9%) patients had transient adverse events, which all resolved with no long-term sequelae. CONCLUSIONS: MR imaging-guided percutaneous cryoablation of metastatic LNs is a safe and technically effective technique for treating metastatic prostate cancer in LNs.


Assuntos
Criocirurgia , Metástase Linfática , Imagem por Ressonância Magnética Intervencionista , Neoplasias da Próstata , Humanos , Masculino , Criocirurgia/efeitos adversos , Neoplasias da Próstata/cirurgia , Neoplasias da Próstata/diagnóstico por imagem , Neoplasias da Próstata/patologia , Idoso , Estudos Retrospectivos , Pessoa de Meia-Idade , Resultado do Tratamento , Fatores de Tempo , Linfonodos/diagnóstico por imagem , Linfonodos/patologia , Linfonodos/cirurgia , Antígeno Prostático Específico/sangue , Idoso de 80 Anos ou mais , Valor Preditivo dos Testes , Calicreínas/sangue
2.
Inflamm Bowel Dis ; 2024 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-38738296

RESUMO

BACKGROUND: Despite advances in medical therapy, many children and adults with ileal Crohn's disease (CD) progress to fibrostenosis requiring surgery. We aimed to identify MRI and circulating biomarkers associated with the need for surgical management. METHODS: This prospective, multicenter study included pediatric and adult CD cases undergoing ileal resection and CD controls receiving medical therapy. Noncontrast research MRI examinations measured bowel wall 3-dimensional magnetization transfer ratio normalized to skeletal muscle (normalized 3D MTR), modified Look-Locker inversion recovery (MOLLI) T1 relaxation, intravoxel incoherent motion (IVIM) diffusion-weighted imaging metrics, and the simplified magnetic resonance index of activity (sMaRIA). Circulating biomarkers were measured on the same day as the research MRI and included CD64, extracellular matrix protein 1 (ECM1), and granulocyte-macrophage colony-stimulating factor (GM-CSF) autoantibodies (Ab). Associations between MRI and circulating biomarkers and need for ileal resection were tested using univariate and multivariable LASSO regression. RESULTS: Our study sample included 50 patients with CD undergoing ileal resection and 83 patients with CD receiving medical therapy; mean participant age was 23.9 ±â€…13.1 years. Disease duration and treatment exposures did not vary between the groups. Univariate biomarker associations with ileal resection included log GM-CSF Ab (odds ratio [OR], 2.87; P = .0009), normalized 3D MTR (OR, 1.05; P = .002), log MOLLI T1 (OR, 0.01; P = .02), log IVIM perfusion fraction (f; OR, 0.38; P = .04), and IVIM apparent diffusion coefficient (ADC; OR, 0.3; P = .001). The multivariable model for surgery based upon corrected Akaike information criterion included age (OR, 1.03; P = .29), BMI (OR, 0.91; P = .09), log GM-CSF Ab (OR, 3.37; P = .01), normalized 3D MTR (OR, 1.07; P = .007), sMaRIA (OR, 1.14; P = .61), luminal narrowing (OR, 10.19; P = .003), log C-reactive protein (normalized; OR, 2.75; P = .10), and hematocrit (OR, 0.90; P = .13). CONCLUSION: After accounting for clinical and MRI measures of severity, normalized 3D MTR and GM-CSF Ab are associated with the need for surgery in ileal CD.


Despite advances in medical therapy, many patients with ileal Crohn's disease progress to fibrostenosis requiring surgery. Our study has shown that GM-CSF autoantibodies and MRI biomarker sequences are associated with the need for ileal resection and may help guide management decisions.

3.
Ann Biomed Eng ; 52(8): 2065-2075, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38634953

RESUMO

MR-guided microwave ablation (MWA) has proven effective in treating hepatocellular carcinoma (HCC) with small-sized tumors, but the state-of-the-art technique suffers from sub-optimal workflow due to the limited accuracy provided by the manual needle insertions. This paper presents a compact body-mounted MR-conditional robot that can operate in closed-bore MR scanners for accurate needle guidance. The robotic platform consists of two stacked Cartesian XY stages, each with two degrees of freedom, that facilitate needle insertion pose control. The robot is actuated using 3D-printed pneumatic turbines with MR-conditional bevel gear transmission systems. Pneumatic valves and control mechatronics are located inside the MRI control room and are connected to the robot with pneumatic transmission lines and optical fibers. Free-space experiments indicated robot-assisted needle insertion error of 2.6 ± 1.3 mm at an insertion depth of 80 mm. The MR-guided phantom studies were conducted to verify the MR-conditionality and targeting performance of the robot. Future work will focus on the system optimization and validations in animal trials.


Assuntos
Imageamento por Ressonância Magnética , Procedimentos Cirúrgicos Robóticos , Procedimentos Cirúrgicos Robóticos/instrumentação , Procedimentos Cirúrgicos Robóticos/métodos , Humanos , Neoplasias Hepáticas/cirurgia , Neoplasias Hepáticas/diagnóstico por imagem , Imagens de Fantasmas , Fígado/cirurgia , Fígado/diagnóstico por imagem , Procedimentos Cirúrgicos Minimamente Invasivos/instrumentação , Robótica/instrumentação , Carcinoma Hepatocelular/cirurgia , Carcinoma Hepatocelular/diagnóstico por imagem , Desenho de Equipamento
4.
Food Chem ; 401: 134127, 2023 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-36096005

RESUMO

In the present study, Ulva prolifera, an edible alga, was used to prepare angiotensin-I converting enzyme (ACE) inhibitory peptide. The algae protein was isolated and later hydrolyzed by five commercial enzymes (alcalase, papain, pepsin, trypsin, neutral protease), either individually or in combination. Hydrolysate, with the highest in vitro ACE inhibitory activity, was processed using the Sephadex-G100, ultrafiltration, HPLC-Q-TOF-MS, ADMET screening and molecular docking, respectively. The ACE inhibitory peptide DIGGL with a IC50 value of 10.32 ± 0.96 µM was then identified. The peptide against ACE by a non-competitive mode and mainly attributable to the three Conventional Hydrogen Bonds. It could activate Endothelial nitric oxide synthase activity in NO generation and reduce Endothelin-1 secretion induced by Angiotensin II in Human umbilical vein endothelial cells. Meanwhile, DIGGL could promote mice splenocytes proliferation, which was also effective when co-incubated with Con A or LPS, respectively. Besides, the anti-ACE peptide could remain active during the digestion of gastrointestinal proteases (pepsin-trypsin) in vitro.


Assuntos
Peptidil Dipeptidase A , Ulva , Animais , Humanos , Camundongos , Peptidil Dipeptidase A/metabolismo , Ulva/metabolismo , Inibidores da Enzima Conversora de Angiotensina/química , Hidrolisados de Proteína/química , Óxido Nítrico Sintase Tipo III , Tripsina/metabolismo , Pepsina A/metabolismo , Simulação de Acoplamento Molecular , Endotelina-1 , Angiotensina II , Papaína , Células Endoteliais/metabolismo , Lipopolissacarídeos , Hidrólise , Peptídeos/química , Peptídeo Hidrolases/metabolismo , Subtilisinas
5.
Br J Radiol ; 95(1140): 20220230, 2022 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-36367095

RESUMO

OBJECTIVE: Investigate the performance of multiparametric MRI radiomic features, alone or combined with current standard-of-care methods, for pulmonary nodule classification. Assess the impact of segmentation variability on feature reproducibility and reliability. METHODS: Radiomic features were extracted from 74 pulmonary nodules of 68 patients who underwent nodule resection or biopsy after MRI exam. The MRI features were compared with histopathology and conventional quantitative imaging values (maximum standardized uptake value [SUVmax] and mean Hounsfield unit [HU]) to determine whether MRI radiomic features can differentiate types of nodules and associate with SUVmax and HU using Wilcoxon rank sum test and linear regression. Diagnostic performance of features and four machine learning (ML) models were evaluated with area under the receiver operating characteristic curve (AUC) and 95% confidence intervals (CIs). Concordance correlation coefficient (CCC) assessed the segmentation variation impact on feature reproducibility and reliability. RESULTS: Elevn diffusion-weighted features distinguished malignant from benign nodules (adjusted p < 0.05, AUC: 0.73-0.81). No features differentiated cancer types. Sixty-seven multiparametric features associated with mean CT HU and 14 correlated with SUVmax. All significant MRI features outperformed traditional imaging parameters (SUVmax, mean HU, apparent diffusion coefficient [ADC], T1, T2, dynamic contrast-enhanced imaging values) in distinguishing malignant from benign nodules with some achieving statistical significance (p < 0.05). Adding ADC and smoking history improved feature performance. Machine learning models demonstrated strong performance in nodule classification, with extreme gradient boosting (XGBoost) having the highest discrimination (AUC = 0.83, CI=[0.727, 0.932]). We found good to excellent inter- and intrareader feature reproducibility and reliability (CCC≥0.80). CONCLUSION: Eleven MRI radiomic features differentiated malignant from benign lung nodules, outperforming traditional quantitative methods. MRI radiomic ML models demonstrated good nodule classification performances with XGBoost superior to three others. There was good to excellent inter- and intrareader feature reproducibility and reliability. ADVANCES IN KNOWLEDGE: Our study identified MRI radiomic features that successfully differentiated malignant from benign lung nodules and demonstrated high performance of our MR radiomic feature-based ML models for nodule classification. These new findings could help further establish thoracic MRI as a non-invasive and radiation-free alternative to standard practice for pulmonary nodule assessment.


Assuntos
Imageamento por Ressonância Magnética , Nódulos Pulmonares Múltiplos , Humanos , Reprodutibilidade dos Testes , Imageamento por Ressonância Magnética/métodos , Nódulos Pulmonares Múltiplos/diagnóstico por imagem , Imagem de Difusão por Ressonância Magnética/métodos , Espectroscopia de Ressonância Magnética , Estudos Retrospectivos
6.
J Neurol Surg B Skull Base ; 83(2): 203-209, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35433184

RESUMO

Objective Therapeutic hypothermia is a potentially powerful and controversial clinical tool for neuroprotection following acute neurologic pathology, particularly vascular injury. Indeed, therapeutic hypothermia remains a standard of care for postcardiac arrest ischemia and acute neonatal hypoxic-ischemic encephalopathy, improving both survival and outcomes. Although therapeutic hypothermia remains promising for cellular and systems-based neuronal protection in other neurologic injury states, the systemic side effects have limited clinical utility, confounded analysis of potential neurologic benefits, and precluded the completion of meaningful clinical trials. Methods To address such limitations, we developed and tested a novel, minimally invasive, neurocritical care device that employs continuous circulation of cold saline through the pharyngeal region to deliver focal cerebrovascular cooling. We conducted a preclinical safety and efficacy trial in six adult porcine animals to assess the validity and functionality of the NeuroSave device, and assess cooling potential following middle cerebral artery occlusion ( n = 2). Results NeuroSave consistently lowered brain parenchymal temperature by a median of 9°C relative to core temperature within 60 minutes of initiation, including in ischemic cerebral parenchyma. The core body temperature experienced a maximal reduction of 2°C, or 5% of body temperature, with no associated adverse effects identified. Conclusion The present study uses a large animal preclinical model to demonstrate the safety and efficacy of a novel, noninvasive device for the induction of robust and systemically safe hypothermia within the brain.

7.
Radiographics ; 41(6): 1785-1801, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34597216

RESUMO

Clinical use of MRI for guidance during interventional procedures emerged shortly after the introduction of clinical diagnostic MRI in the late 1980s. However, early applications of interventional MRI (iMRI) were limited owing to the lack of dedicated iMRI magnets, pulse sequences, and equipment. During the 3 decades that followed, technologic advancements in iMRI magnets that balance bore access and field strength, combined with the development of rapid MRI pulse sequences, surface coils, and commercially available MR-conditional devices, led to the rapid expansion of clinical iMRI applications, particularly in the field of body iMRI. iMRI offers several advantages, including superior soft-tissue resolution, ease of multiplanar imaging, lack of ionizing radiation, and capability to re-image the same section. Disadvantages include longer examination times, lack of MR-conditional equipment, less operator familiarity, and increased cost. Nonetheless, MRI guidance is particularly advantageous when the disease is best visualized with MRI and/or when superior soft-tissue contrast is needed for treatment monitoring. Safety in the iMRI environment is paramount and requires close collaboration among interventional radiologists, MR physicists, and all other iMRI team members. The implementation of risk-limiting measures for personnel and equipment in MR zones III and IV is key. Various commercially available MR-conditional needles, wires, and biopsy and ablation devices are now available throughout the world, depending on the local regulatory status. As such, there has been tremendous growth in the clinical applications of body iMRI, including localization of difficult lesions, biopsy, sclerotherapy, and cryoablation and thermal ablation of malignant and nonmalignant soft-tissue neoplasms. Online supplemental material is available for this article. ©RSNA, 2021.


Assuntos
Imagem por Ressonância Magnética Intervencionista , Biópsia , Previsões , Humanos , Imageamento por Ressonância Magnética , Radiologistas
8.
Plast Reconstr Surg ; 148(1): 77e-82e, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-34076611

RESUMO

SUMMARY: Advances in virtual surgical planning and three-dimensionally-printed guides have enabled increased precision in vascularized free fibula flap reconstruction of the mandible and valuable preoperative planning. However, virtual surgical planning currently requires high-resolution computed tomographic scans, exposing patients to ionizing radiation. The aim of this study was to determine whether black bone magnetic resonance imaging can be used for accurate surgical planning and three-dimensionally-printed guide creation, thus reducing patient radiation exposure. This study included 10 cadaver heads and 10 cadaver lower extremities. A mock fibula free flap for mandible reconstruction was performed. Five operations were planned with guides created using black bone magnetic resonance imaging, whereas the other five were planned and performed using guides created with computed tomographic scan data. All specimens underwent a postoperative computed tomographic scan, and three-dimensional reconstruction of scans was performed and surgical accuracy to the planned surgery was assessed. Guides created from black bone magnetic resonance imaging demonstrated high accuracy to the surgical plan. There was no statistically significant difference in postoperative deviation from the plan when black bone magnetic resonance imaging versus computed tomographic scanning was used for virtual surgical planning and guide creation. Both modalities led to a postoperative positive or negative deviation from the virtual plan within 0.8 mm. This study demonstrates that virtual surgical planning and three-dimensionally-printed guide creation for free fibula flaps for mandible reconstruction can be performed using black bone magnetic resonance imaging with comparable accuracy to computed tomographic scanning. This could reduce radiation exposure for patients and enable a more streamlined imaging process for head and neck cancer patients.


Assuntos
Fíbula/transplante , Imageamento por Ressonância Magnética , Mandíbula/diagnóstico por imagem , Reconstrução Mandibular/métodos , Planejamento de Assistência ao Paciente , Cadáver , Retalhos de Tecido Biológico/transplante , Neoplasias de Cabeça e Pescoço/cirurgia , Humanos , Imageamento Tridimensional , Mandíbula/cirurgia , Modelos Anatômicos , Impressão Tridimensional , Exposição à Radiação/efeitos adversos , Tomografia Computadorizada por Raios X , Resultado do Tratamento
9.
MAGMA ; 34(5): 697-706, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33945050

RESUMO

PURPOSE: MR fingerprinting (MRF) is a MR technique that allows assessment of tissue relaxation times. The purpose of this study is to evaluate the clinical application of this technique in patients with meningioma. MATERIALS AND METHODS: A whole-brain 3D isotropic 1mm3 acquisition under a 3.0T field strength was used to obtain MRF T1 and T2-based relaxometry values in 4:38 s. The accuracy of values was quantified by scanning a quantitative MR relaxometry phantom. In vivo evaluation was performed by applying the sequence to 20 subjects with 25 meningiomas. Regions of interest included the meningioma, caudate head, centrum semiovale, contralateral white matter and thalamus. For both phantom and subjects, mean values of both T1 and T2 estimates were obtained. Statistical significance of differences in mean values between the meningioma and other brain structures was tested using a Friedman's ANOVA test. RESULTS: MR fingerprinting phantom data demonstrated a linear relationship between measured and reference relaxometry estimates for both T1 (r2 = 0.99) and T2 (r2 = 0.97). MRF T1 relaxation times were longer in meningioma (mean ± SD 1429 ± 202 ms) compared to thalamus (mean ± SD 1054 ± 58 ms; p = 0.004), centrum semiovale (mean ± SD 825 ± 42 ms; p < 0.001) and contralateral white matter (mean ± SD 799 ± 40 ms; p < 0.001). MRF T2 relaxation times were longer for meningioma (mean ± SD 69 ± 27 ms) as compared to thalamus (mean ± SD 27 ± 3 ms; p < 0.001), caudate head (mean ± SD 39 ± 5 ms; p < 0.001) and contralateral white matter (mean ± SD 35 ± 4 ms; p < 0.001) CONCLUSIONS: Phantom measurements indicate that the proposed 3D-MRF sequence relaxometry estimations are valid and reproducible. For in vivo, entire brain coverage was obtained in clinically feasible time and allows quantitative assessment of meningioma in clinical practice.


Assuntos
Neoplasias Meníngeas , Meningioma , Encéfalo/diagnóstico por imagem , Estudos de Viabilidade , Humanos , Imageamento por Ressonância Magnética , Neoplasias Meníngeas/diagnóstico por imagem , Meningioma/diagnóstico por imagem , Imagens de Fantasmas
10.
J Vasc Interv Radiol ; 32(5): 721-728.e2, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33663924

RESUMO

PURPOSE: To investigate cryoneedle heating risks during magnetic resonance (MR)-guided cryoablation and potential strategies to mitigate these risks. MATERIALS AND METHODS: Ex vivo experiments were performed on a 1.5-Tesla (T) MR scanner using an MR conditional cryoablation system on porcine tissue phantoms. Cryoneedles were placed inside the tissue phantom either with or without an angiocatheter. Typical cryoneedle geometric configurations (including gas supply line) encountered in clinical procedures with low to high expected heating risks were investigated. Up to 4 fiber optic temperature sensors were attached to the cryoneedle/angiocatheter to measure the MR-induced cryoneedle heating at different locations during MR with different estimated specific absorption rates (SARs). The impact of cryoneedle heating on cryoablation treatment was studied by comparing temperature changes during 10-min freeze-thaw cycles with and without MR. RESULTS: Rapid temperature increases of >100 °C in < 2 minutes were observed during MR with a SAR of 2.1 W/kg. The temperature changes during a typical freeze-thaw cycle were also affected by cryoneedle heating when MR was used to monitor the ice-ball evolution. The observed cryoneedle heating was affected by multiple factors; including cryoneedle geometric configurations, sequence SAR, whether an angiocatheter was used, and whether the cryoneedle was connected to the rest of the cryoablation system. CONCLUSIONS: The ex vivo experiments demonstrated that MR could induce significant cryoneedle heating risks. Furthermore, MR-induced cryoneedle heating can affect temperatures in the ice-ball evolution during the freeze-thaw cycle. Several practical strategies to reduce the cryoneedle heating have been proposed.


Assuntos
Criocirurgia/instrumentação , Imagem por Ressonância Magnética Intervencionista , Agulhas , Temperatura , Animais , Catéteres , Criocirurgia/efeitos adversos , Imagem por Ressonância Magnética Intervencionista/efeitos adversos , Carne de Porco , Medição de Risco , Fatores de Risco , Sus scrofa , Fatores de Tempo
11.
Phys Med ; 71: 100-107, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32114323

RESUMO

MRI-guided microwave ablation (MWA) is a minimally invasive treatment for localized cancer. MR thermometry has been shown to be able to provide vital information for monitoring the procedure in real-time. However, MRI during active MWA can suffer from image quality degradation due to intermittent electromagnetic interference (EMI). A novel approach to correct for EMI-contaminated images is presented here to improve MR thermometry during clinical hepatic MWA. The method was applied to MR-thermometry images acquired during four MR-guided hepatic MWA treatments using a commercially available MRI-configured microwave generator system. During the treatments MR thermometry data acquisition was synchronized to respiratory cycle to minimize the impact of motion. EMI was detected and corrected using uncontaminated k-space data from nearby frames in k-space. Substantially improved temperature and thermal damage maps have been obtained and the treatment zone can be better visualized. Our ex vivo tissue sample study shows the correction introduced minimal errors to the temperature maps and thermal damage maps.


Assuntos
Processamento de Imagem Assistida por Computador/métodos , Fígado/diagnóstico por imagem , Imageamento por Ressonância Magnética , Micro-Ondas , Terapia por Radiofrequência , Termometria , Algoritmos , Artefatos , Radiação Eletromagnética , Análise de Fourier , Humanos , Reprodutibilidade dos Testes , Razão Sinal-Ruído
12.
Abdom Radiol (NY) ; 45(4): 1155-1161, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-31359096

RESUMO

PURPOSE: To describe safety, efficacy, and added oncologic margin of saline displacement of the rectal wall during MRI-guided cryoablation of primary and recurrent prostate cancer. METHODS: A retrospective review was conducted for patients who underwent MRI-guided cryoablation with saline displacement of the rectal wall for treatment of primary and recurrent prostate cancer over a 2-year period. Saline displacement was used when the distance from the edge of the ablation area to the rectal wall was insufficient to provide at least a 5-mm treatment margin. Pre- and post-ablation rectal wall displacement distances as well as ablative zone margins were assessed with MRI. Saline displacement distance was measured from the rectal wall to the edge of the lesion for focal lesion ablation and from the edge of the prostate for hemi-gland ablation. Immediate and intermediate-term complications were assessed. RESULTS: Saline displacement was used in 25 patients undergoing MRI-guided cryoablation. Twenty-one patients underwent salvage cryoablation, while four patients had it as primary treatment for prostate cancer. Median pre- and post- saline displacement rectal wall displacement distances were 6.0 and 11.2 mm, respectively (P < 0.0001). Median-added oncologic margin achieved by saline displacement was 4.6 mm (range 0.6-26.5). Median follow-up was 14 months (range 5-29). There were no intra-procedural complications and 3 patients experienced minor (Clavien-Dindo grade I) complications. One rectal complication occurred in a patient undergoing salvage cryotherapy with a history of extensive pelvic surgery and radiation. CONCLUSIONS: Saline infusion at the time of MRI- guided cryoablation for prostate cancer resulted in increased distances between the target lesion and rectum. This is a useful technique in providing an added oncologic margin when treating lesions close to the rectal wall.


Assuntos
Criocirurgia/métodos , Imagem por Ressonância Magnética Intervencionista , Recidiva Local de Neoplasia/cirurgia , Neoplasias da Próstata/cirurgia , Reto , Cloreto de Sódio/administração & dosagem , Idoso , Idoso de 80 Anos ou mais , Humanos , Masculino , Margens de Excisão , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/patologia , Complicações Pós-Operatórias , Neoplasias da Próstata/patologia , Estudos Retrospectivos
13.
J Magn Reson ; 307: 106582, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31499470

RESUMO

Quantitative measurement of the tissue sodium concentration (TSC) provides a metric for tissue cell volume fraction for monitoring tumor responses to therapy and neurodegeneration in the brain as well as applications outside the central nervous system such as the fixed charge density in cartilage. Despite the low detection sensitivity of the sodium MR signal compared to the proton signal and the requirement for a long repetition time to minimize longitudinal magnetization saturation, acquisition time has been reduced to less than 10 min for a nominal isotropic voxel size of 3.3 mm with the improved acquisition efficiency of twisted projection imaging (TPI) at 9.4 T. However, patient motion can degrade the accuracy of the quantification even within these acquisition times. Our goal has been to improve the robustness of quantitative sodium MR imaging by minimizing the impact of motion that may occur even in cooperative patients. We present a method to spatially encode a lower resolution navigator echo after encoding the free induction decay signal for the quantitative image at no time penalty. Both the imaging and navigator data are sampled with flexTPI readout trajectories. Navigator images are generated at a higher temporal resolution (∼1 min) albeit at lower spatial resolution (8 mm) than the quantitative high-resolution images. The multiple volumes of navigator echo images are then aligned to extract the translational and rotational motion parameters assuming rigid-body motion. These parameters are used to align the k-space data during the acquisition of each volume of the quantitative images. Our results show significantly reduced image blurring with this method when the subject's head moved randomly by up to 7° between the navigator acquisitions.


Assuntos
Química Encefálica , Encéfalo/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos , Sódio/química , Algoritmos , Artefatos , Encefalopatias/diagnóstico por imagem , Simulação por Computador , Humanos , Aumento da Imagem , Processamento de Imagem Assistida por Computador , Movimento (Física) , Neuroimagem , Imagens de Fantasmas , Reprodutibilidade dos Testes
14.
Clin Cancer Res ; 25(4): 1226-1232, 2019 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-30487127

RESUMO

PURPOSE: Spatial and temporal patterns of response of human glioblastoma to fractionated chemoradiation are described by changes in the bioscales of residual tumor volume (RTV), tumor cell volume fraction (CVF), and tumor cell kill (TCK), as derived from tissue sodium concentration (TSC) measured by quantitative sodium MRI at 3 Tesla. These near real-time patterns during treatment are compared with overall survival. EXPERIMENTAL DESIGN: Bioscales were mapped during fractionated chemoradiation therapy in patients with glioblastomas (n = 20) using TSC obtained from serial quantitative sodium MRI at 3 Tesla and a two-compartment model of tissue sodium distribution. The responses of these parameters in newly diagnosed human glioblastomas undergoing treatment were compared with time-to-disease progression and survival. RESULTS: RTV following tumor resection showed decreased CVF due to disruption of normal cell packing by edema and infiltrating tumor cells. CVF showed either increases back toward normal as infiltrating tumor cells were killed, or decreases as cancer cells continued to infiltrate and extend tumor margins. These highly variable tumor responses showed no correlation with time-to-progression or overall survival. CONCLUSIONS: These bioscales indicate that fractionated chemoradiotherapy of glioblastomas produces variable responses with low cell killing efficiency. These parameters are sensitive to real-time changes within the treatment volume while remaining stable elsewhere, highlighting the potential to individualize therapy earlier in management, should alternative strategies be available.


Assuntos
Quimiorradioterapia , Glioblastoma/diagnóstico por imagem , Neoplasia Residual/diagnóstico por imagem , Adulto , Idoso , Tamanho Celular/efeitos dos fármacos , Tamanho Celular/efeitos da radiação , Progressão da Doença , Fracionamento da Dose de Radiação , Feminino , Glioblastoma/tratamento farmacológico , Glioblastoma/patologia , Glioblastoma/radioterapia , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Neoplasia Residual/tratamento farmacológico , Neoplasia Residual/patologia , Neoplasia Residual/radioterapia , Sódio/uso terapêutico , Carga Tumoral/efeitos dos fármacos , Carga Tumoral/efeitos da radiação
15.
J Magn Reson Imaging ; 49(7): e256-e264, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30575193

RESUMO

BACKGROUND: There is no accurate method distinguishing different types of pulmonary nodules. PURPOSE: To investigate whether multiparametric 3T MRI biomarkers can distinguish malignant from benign pulmonary nodules, differentiate different types of neoplasms, and compare MRI-derived measurements with values from commonly used noninvasive imaging modalities. STUDY TYPE: Prospective. SUBJECTS: Sixty-eight adults with pulmonary nodules undergoing resection. SEQUENCES: Respiratory triggered diffusion-weighted imaging (DWI), periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER) fat saturated T2 -weighted imaging, T1 -weighted 3D volumetric interpolated breath-hold examination (VIBE) using CAIPIRINHA (controlled aliasing in parallel imaging results in a higher acceleration). ASSESSMENT/STATISTICS: Apparent diffusion coefficient (ADC), T1 , T2 , T1 and T2 normalized to muscle (T1 /M and T2 /M), and dynamic contrast enhancement (DCE) values were compared with histology to determine whether they could distinguish malignant from benign nodules and discern primary from secondary malignancies using logistic regression. Predictability of primary neoplasm types was assessed using two-sample t-tests. MRI values were compared with positron emission tomography / computed tomography (PET/CT) to examine if they correlated with standardized uptake value (SUV) or CT Hounsfield unit (HU). Intra- and interreader agreements were assessed using intraclass correlations. RESULTS: Forty-nine of 74 nodules were malignant. There was a significant association between ADC and malignancy (odds ratio 4.47, P < 0.05). ADC ≥1.3 µm2 /ms predicted malignancy. ADC, T1 , and T2 together predicted malignancy (P = 0.003). No MRI parameter distinguished primary from metastatic neoplasms. T2 predicted PET positivity (P = 0.016). T2 and T1 /M correlated with SUV (P < 0.05). Of 18 PET-negative malignant nodules, 12 (67%) had an ADC ≥1.3 µm2 /ms. With the exception of T2 , all noncontrast MRI parameters distinguished adenocarcinomas from carcinoid tumors (P < 0.05). T1 , T2 , T1 /M, and T2 /M correlated with HU and therefore can predict nodule density. Combined with ADC, washout enhancement, arrival time (AT), peak enhancement intensity (PEI), Ktrans , Kep , Ve collectively were predictive of malignancy (P = 0.012). Combined washin, washout, time to peak (TTP), AT, and PEI values predicted malignancy (P = 0.043). There was good observer agreement for most noncontrast MRI biomarkers. DATA CONCLUSION: MRI can contribute to pulmonary nodule analysis. Multiparametric MRI might be better than individual MRI biomarkers in pulmonary nodule risk stratification. LEVEL OF EVIDENCE: 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018.


Assuntos
Neoplasias Pulmonares/diagnóstico por imagem , Imageamento por Ressonância Magnética , Nódulos Pulmonares Múltiplos/diagnóstico por imagem , Nódulo Pulmonar Solitário/diagnóstico por imagem , Adulto , Idoso , Idoso de 80 Anos ou mais , Diagnóstico por Computador , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Neoplasias Pulmonares/cirurgia , Masculino , Pessoa de Meia-Idade , Nódulos Pulmonares Múltiplos/cirurgia , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Risco , Nódulo Pulmonar Solitário/cirurgia
16.
PLoS One ; 13(1): e0190890, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29309426

RESUMO

Magnetic resonance imaging is considered low risk, yet recent studies have raised a concern of potential damage to DNA in peripheral blood leukocytes. This prospective Institutional Review Board-approved study examined potential double-strand DNA damage by analyzing changes in the DNA damage and repair markers γH2AX and 53BP1 in patients who underwent a 1.5 T gadolinium-enhanced cardiac magnetic resonance (MR) exam. Sixty patients were enrolled (median age 55 years, 39 males). Patients with history of malignancy or who were receiving chemotherapy, radiation therapy, or steroids were excluded. MR sequence data were recorded and blood samples obtained immediately before and after MR exposure. An automated immunofluorescence assay quantified γH2AX or 53BP1 foci number in isolated peripheral blood mononuclear cells. Changes in foci number were analyzed using the Wilcoxon signed-rank test. Clinical and MR procedural characteristics were compared between patients who had a >10% increase in γH2AX or 53BP1 foci numbers and patients who did not. The number of γH2AX foci did not significantly change following cardiac MR (median foci per cell pre-MR = 0.11, post-MR = 0.11, p = .90), but the number of 53BP1 foci significantly increased following MR (median foci per cell pre-MR = 0.46, post-MR = 0.54, p = .0140). Clinical and MR characteristics did not differ significantly between patients who had at least a 10% increase in foci per cell and those who did not. We conclude that MR exposure leads to a small (median 25%) increase in 53BP1 foci, however the clinical relevance of this increase is unknown and may be attributable to normal variation instead of MR exposure.


Assuntos
Biomarcadores/metabolismo , Dano ao DNA , Reparo do DNA , Gadolínio/administração & dosagem , Coração/diagnóstico por imagem , Histonas/metabolismo , Imageamento por Ressonância Magnética/métodos , Proteína 1 de Ligação à Proteína Supressora de Tumor p53/metabolismo , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Estudos Retrospectivos
17.
J Magn Reson Imaging ; 43(2): 512-32, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26223818

RESUMO

BACKGROUND: To determine the accuracy of pulmonary MR imaging with ultrashort echo time (UTE) for lung and mediastinum assessments using computed tomography (CT) as the reference standard, for various pulmonary parenchyma diseases. METHODS: Eight-five consecutive patients (46 males: mean age, 69 years and 39 females: mean age, 69 years) with various pulmonary parenchyma diseases were examined with chest standard- and low-dose CTs and pulmonary MR imaging with UTE. This was followed by visual assessment using a 5-point system of the presence of nodules or masses, ground-glass opacity, micronodules, nodules, patchy shadow or consolidation, emphysema or bullae, bronchiectasis, reticular opacity, and honeycomb and traction bronchiectasis. Presence of aneurysms, pleural or pericardial effusions, pleural thickening or tumor, and lymph adenopathy was also evaluated using a 5-point system. To compare the capability of the methods for lung parenchyma and mediastinum evaluation, intermethod agreement was evaluated by means of kappa statistics and χ2 test. Receiver operating characteristic analyses were used to compare diagnostic performance of all methods. RESULTS: Intermethod agreements between pulmonary MR imaging and standard-dose and low-dose CT were significant and either substantial or almost perfect (0.67 ≤ κ ≤ 0.98; P < 0.0001). Areas under the curve for emphysema or bullae, bronchiectasis or traction bronchiectasis and reticular opacity on standard-dose CT were significantly larger than those on low-dose CT (emphysema or bullae: P = 0.0002; reticular opacity: P < 0.0001) and pulmonary MR imaging (emphysema or bullae: P < 0.0001; bronchiectasis: P = 0.008; reticular opacity: P < 0.0001). CONCLUSION: Pulmonary MR imaging with UTE is useful for lung and mediastinum assessment and evaluation of radiological findings for patients with various pulmonary parenchyma diseases.


Assuntos
Pneumopatias/diagnóstico por imagem , Pneumopatias/patologia , Imageamento por Ressonância Magnética/métodos , Doses de Radiação , Tomografia Computadorizada por Raios X/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Pulmão/diagnóstico por imagem , Pulmão/patologia , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Reprodutibilidade dos Testes
18.
Magn Reson Med ; 69(2): 538-44, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22529019

RESUMO

Quantitative (31)P magnetic resonance imaging of the whole human brain is often time-consuming even at low spatial resolution due to the low concentrations, long T(1) relaxation times, and low detection sensitivity of phosphorus metabolites. We report herein the results of combining the increased detection sensitivity of an ultra-high field 9.4 T scanner designed for human imaging with a new pulse sequence termed simultaneously imaging of multiple spectral peaks with interleaved excitations and flexible twisted projection imaging readout trajectories to rapidly sample multiple resonances in the (31)P spectrum. The phosphocreatine and γ-adenosine triphosphate images, obtained simultaneously from the entire human head, are demonstrated at 1.5 cm isotropic nominal resolution in a total acquisition time of 33 min. The phosphocreatine/γ-adenosine triphosphate ratio calculated for brain parenchyma (1-2) and the superficial temporalis muscle (3-5) are in agreement with literature values.


Assuntos
Trifosfato de Adenosina/metabolismo , Algoritmos , Encéfalo/metabolismo , Interpretação de Imagem Assistida por Computador/métodos , Imageamento por Ressonância Magnética/métodos , Fosfocreatina/metabolismo , Fósforo/farmacocinética , Encéfalo/anatomia & histologia , Humanos , Aumento da Imagem/métodos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Distribuição Tecidual
19.
Magn Reson Med ; 68(3): 751-61, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22139900

RESUMO

Emerging applications of sodium bioscales derived from quantitative sodium magnetic resonance imaging assess temporal changes in regional sodium concentration over intervals that vary from hours (monitoring tissue viability in stroke) to weeks (monitoring brain tumor treatment during radiation therapy) or even years (monitoring progression of neurodegenerative disease). Accurate interpretation of such quantitative data requires precise registration between magnetic resonance imaging sessions to avoid session-to-session changes in partial volume effects between normal tissue (∼38 mM sodium concentration), lesions (variable sodium concentration), and cerebrospinal fluid (∼144 mM sodium concentration). The existing Automated Image Registration algorithm is shown to be suitable for rapid, accurate, and precise determination of the transform that aligns sodium magnetic resonance images. Implementation of this transform during image reconstruction from the k-space data is shown to produce smaller errors than conventional image-domain interpolation. Experimental results at 9.4 T and 3.0 T demonstrating this registration approach to sodium data illustrate preservation of quantification accuracy during alignment of sodium magnetic resonance images acquired from the same subject during different imaging sessions.


Assuntos
Algoritmos , Encéfalo/anatomia & histologia , Encéfalo/metabolismo , Interpretação de Imagem Assistida por Computador/métodos , Imageamento por Ressonância Magnética/métodos , Sódio/análise , Técnica de Subtração , Humanos , Aumento da Imagem/métodos , Estudos Longitudinais , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Distribuição Tecidual
20.
Magn Reson Med ; 66(6): 1582-9, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21630347

RESUMO

While temperature mapping is desired during cryosurgery for prostate cancer treatment, an effective approach for this purpose is still needed. We have demonstrated a phase shift with temperature in our in vivo canine experiments and ex vivo tissue sample experiments within the frozen tissue. The phase shift is much larger (~0.7 °/°C with an echo time of 0.1 ms at 0.5 T) in magnitude than that predicted by conventional proton resonant frequency shift (0.008 °/°C). It shows little dependence on the echo times used and thus is not due to a frequency change, although frequency-dependent phase shift has been observed near the frozen tissue. This phase shift varies monotonically with temperature within the frozen tissue and therefore may be potentially used as a novel temperature mapping approach in cryoablation applications.


Assuntos
Criocirurgia , Congelamento , Interpretação de Imagem Assistida por Computador/métodos , Imageamento por Ressonância Magnética/métodos , Próstata/fisiologia , Próstata/cirurgia , Prostatectomia , Animais , Cães , Masculino , Próstata/anatomia & histologia , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
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