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1.
Radiol Artif Intell ; 4(6): e210294, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36523641

RESUMO

Purpose: To design and evaluate an automated deep learning method for segmentation and analysis of cardiac MRI T1 maps with use of synthetic T1-weighted images for MRI relaxation-based contrast augmentation. Materials and Methods: This retrospective study included MRI scans acquired between 2016 and 2019 from 100 patients (mean age ± SD, 55 years ± 13; 72 men) across various clinical abnormalities with use of a modified Look-Locker inversion recovery, or MOLLI, sequence to quantify native T1 (T1native), postcontrast T1 (T1post), and extracellular volume (ECV). Data were divided into training (n = 60) and internal (n = 40) test subsets. "Synthetic" T1-weighted images were generated from the T1 exponential inversion-recovery signal model at a range of optimal inversion times, yielding high blood-myocardium contrast, and were used for contrast-based image augmentation during training and testing of a convolutional neural network for myocardial segmentation. Automated segmentation, T1, and ECV were compared with experts with use of Dice similarity coefficients (DSCs), correlation coefficients, and Bland-Altman analysis. An external test dataset (n = 147) was used to assess model generalization. Results: Internal testing showed high myocardial DSC relative to experts (0.81 ± 0.08), which was similar to interobserver DSC (0.81 ± 0.08). Automated segmental measurements strongly correlated with experts (T1native, R = 0.87; T1post, R = 0.91; ECV, R = 0.92), which were similar to interobserver correlation (T1native, R = 0.86; T1post, R = 0.94; ECV, R = 0.95). External testing showed strong DSC (0.80 ± 0.09) and T1native correlation (R = 0.88) between automatic and expert analysis. Conclusion: This deep learning method leveraging synthetic contrast augmentation may provide accurate automated T1 and ECV analysis for cardiac MRI data acquired across different abnormalities, centers, scanners, and T1 sequences.Keywords: MRI, Cardiac, Tissue Characterization, Segmentation, Convolutional Neural Network, Deep Learning Algorithms, Machine Learning Algorithms, Supervised Learning Supplemental material is available for this article. © RSNA, 2022.

2.
IEEE Trans Biomed Eng ; 69(8): 2657-2666, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35171765

RESUMO

OBJECTIVE: Radiofrequency (RF) energy delivered to cardiac tissue produces a core ablation lesion with surrounding edema, the latter of which has been implicated in acute procedural failure of Ventricular Tachycardia (VT) ablation and late arrhythmia recurrence. This study sought to investigate the electrophysiological characteristics of acute RF lesions in the left ventricle (LV) visualized with native-contrast Magnetic Resonance Imaging (MRI). METHODS: An MR-guided electrophysiology system was used to deliver RF ablation in the LV of 8 swine (9 RF lesions in total), then perform MRI and electroanatomic mapping. The permanent RF lesions and transient edema were delineated via native-contrast MRI segmentation of T1-weighted images and T2 maps respectively. Bipolar voltage measurements were matched with image characteristics of pixels adjacent to the catheter tip. Native-contrast MR visualization was verified with 3D late gadolinium enhanced MRI and histology. RESULTS: The T2-derived edema was significantly larger than the T1-derived RF lesion (2.1 ±1.5 mL compared to 0.58 ±0.34 mL; p=0.01). Bipolar voltage was significantly reduced in the presence of RF lesion core (p 0.05) and edema (p 0.05), with similar trends suggesting that both the permanent lesion and transient edema contributed to the region of reduced voltage. While bipolar voltage was significantly decreased where RF lesions are present (p 0.05), voltage did not change significantly with lesion transmurality (p 0.05). CONCLUSION: Permanent RF lesions and transient edema are distinct in native-contrast MR images, but not differentiable using bipolar voltage. SIGNIFICANCE: Intraprocedural native-contrast MRI may provide valuable lesion assessment in MR-guided ablation, whose clinical application is now feasible.


Assuntos
Ablação por Cateter , Ablação por Radiofrequência , Animais , Ablação por Cateter/métodos , Coração , Ventrículos do Coração , Imageamento por Ressonância Magnética/métodos , Ablação por Radiofrequência/métodos , Suínos
4.
NMR Biomed ; 35(3): e4643, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-34791720

RESUMO

Stress imaging identifies ischemic myocardium by comparing hemodynamics during rest and hyperemic stress. Hyperemia affects multiple hemodynamic parameters in myocardium, including myocardial blood flow (MBF), myocardial blood volume (MBV), and venous blood oxygen levels (PvO2 ). Cardiac T2 is sensitive to these changes and therefore is a promising non-contrast option for stress imaging; however, the impact of individual hemodynamic factors on T2 is poorly understood, making the connection from altered T2 to changes within the tissue difficult. To better understand this interplay, we performed T2 mapping and measured various hemodynamic factors independently in healthy pigs at multiple levels of hyperemic stress, induced by different doses of adenosine (0.14-0.56 mg/kg/min). T1 mapping quantified changes in MBV. MBF was assessed with microspheres, and oxygen consumption was determined by the rate pressure product (RPP). Simulations were also run to better characterize individual contributions to T2. Myocardial T2, MBF, oxygen consumption, and MBV all changed to varying extents between each level of adenosine stress (T2 = 37.6-41.8 ms; MBF = 0.48-1.32 mL/min/g; RPP = 6507-4001 bmp*mmHg; maximum percent change in MBV = 1.31%). Multivariable analyses revealed MBF as the dominant influence on T2 during hyperemia (significant ß-values >7). Myocardial oxygen consumption had almost no effect on T2 (ß-values <0.002); since PvO2 is influenced by both oxygen consumption and MBF, PvO2 changes detected by T2 during adenosine stress can be attributed to MBF. Simulations varying PvO2 and MBV confirmed that PvO2 had the strongest influence on T2, but MBV became important at high PvO2 . Together, these data suggest a model where, during adenosine stress, myocardial T2 responds predominantly to changes in MBF, but at high hyperemia MBV is also influential. Thus, changes in adenosine stress T2 can now be interpreted in terms of the physiological changes that led to it, enabling T2 mapping to become a viable non-contrast option to detect ischemic myocardial tissue.


Assuntos
Adenosina/farmacologia , Circulação Coronária/fisiologia , Coração/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos , Animais , Feminino , Hemodinâmica/efeitos dos fármacos , Hiperemia/diagnóstico por imagem , Hiperemia/fisiopatologia , Masculino , Microesferas , Isquemia Miocárdica/diagnóstico por imagem , Oxigênio/sangue , Consumo de Oxigênio , Suínos
5.
Lancet Oncol ; 22(7): 970-976, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34051879

RESUMO

BACKGROUND: The COVID-19 pandemic has disrupted health-care systems, leading to concerns about its subsequent impact on non-COVID disease conditions. The diagnosis and management of cancer is time sensitive and is likely to be substantially affected by these disruptions. We aimed to assess the impact of the COVID-19 pandemic on cancer care in India. METHODS: We did an ambidirectional cohort study at 41 cancer centres across India that were members of the National Cancer Grid of India to compare provision of oncology services between March 1 and May 31, 2020, with the same time period in 2019. We collected data on new patient registrations, number of patients visiting outpatient clinics, hospital admissions, day care admissions for chemotherapy, minor and major surgeries, patients accessing radiotherapy, diagnostic tests done (pathology reports, CT scans, MRI scans), and palliative care referrals. We also obtained estimates from participating centres on cancer screening, research, and educational activities (teaching of postgraduate students and trainees). We calculated proportional reductions in the provision of oncology services in 2020, compared with 2019. FINDINGS: Between March 1 and May 31, 2020, the number of new patients registered decreased from 112 270 to 51 760 (54% reduction), patients who had follow-up visits decreased from 634 745 to 340 984 (46% reduction), hospital admissions decreased from 88 801 to 56 885 (36% reduction), outpatient chemotherapy decreased from 173634 to 109 107 (37% reduction), the number of major surgeries decreased from 17 120 to 8677 (49% reduction), minor surgeries from 18 004 to 8630 (52% reduction), patients accessing radiotherapy from 51 142 to 39 365 (23% reduction), pathological diagnostic tests from 398 373 to 246 616 (38% reduction), number of radiological diagnostic tests from 93 449 to 53 560 (43% reduction), and palliative care referrals from 19 474 to 13 890 (29% reduction). These reductions were even more marked between April and May, 2020. Cancer screening was stopped completely or was functioning at less than 25% of usual capacity at more than 70% of centres during these months. Reductions in the provision of oncology services were higher for centres in tier 1 cities (larger cities) than tier 2 and 3 cities (smaller cities). INTERPRETATION: The COVID-19 pandemic has had considerable impact on the delivery of oncology services in India. The long-term impact of cessation of cancer screening and delayed hospital visits on cancer stage migration and outcomes are likely to be substantial. FUNDING: None. TRANSLATION: For the Hindi translation of the abstract see Supplementary Materials section.


Assuntos
COVID-19/terapia , Prestação Integrada de Cuidados de Saúde/tendências , Acessibilidade aos Serviços de Saúde/tendências , Oncologia/tendências , Neoplasias/terapia , Assistência Ambulatorial/tendências , COVID-19/diagnóstico , Diagnóstico Tardio , Detecção Precoce de Câncer/tendências , Hospitalização/tendências , Hospitais com Alto Volume de Atendimentos/tendências , Humanos , Índia/epidemiologia , Neoplasias/diagnóstico , Neoplasias/epidemiologia , Aceitação pelo Paciente de Cuidados de Saúde , Fatores de Tempo , Tempo para o Tratamento , Listas de Espera
6.
Urol Ann ; 13(1): 76-79, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33897170

RESUMO

A 22-year-old known case of 45XO/46XY mixed gonadal dysgenesis, reared as a male, presented with complaints of suprapubic and left iliac fossa pain for the past 1 month. The patient underwent laparoscopic right orchidectomy (streak) + Mullerian remnant excision + left orchidopexy + first-stage hypospadias repair 10 years back. Contrast-enhanced computed tomography showed a large complex cyst in the left side of the pelvis and rectovesical space. Excision of the cystic structure was done along with left orchidectomy. Histopathological examination revealed features of Mullerian remnants (endometrial glands and cervix) in the cystic structure. The importance of this case report is to emphasize the fact that the Mullerian remnants tend to enlarge in size over time and become symptomatic and may require a surgical removal at a later date as in our case.

7.
Med Phys ; 48(4): 1815-1822, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33417726

RESUMO

PURPOSE: Cardiac relaxometry techniques, particularly T1 mapping, have recently gained clinical importance in various cardiac pathologies. Myocardial T1 and extracellular volume are usually calculated from manual identification of left ventricular epicardial and endocardial regions. This is a laborious process, particularly for large volume studies. Here we present a fully automated relaxometry framework (FASTR) for segmental analysis of T1 maps (both native and postcontrast) and partition coefficient (λ). METHODS: Patients (N = 11) were imaged postacute myocardial infarction on a 1.5T clinical scanner. The scan protocol involved CINE-SSFP imaging, native, and post-contrast T1 mapping using the Modified Look-Locker Inversion (MOLLI) recovery sequence. FASTR consisted of automatic myocardial segmentation of spatio-temporally coregistered CINE images as an initial guess, followed by refinement of the contours on the T1 maps to derive segmental T1 and λ. T1 and λ were then compared to those obtained from two trained expert observers. RESULTS: Robust endocardial and epicardial contours were achieved on T1 maps despite the presence of infarcted tissue. Relative to experts, FASTR resulted in myocardial Dice coefficients (native T1: 0.752 ± 0.041; postcontrast T1: 0.751 ± 0.057) that were comparable to interobserver Dice (native T1: 0.803 ± 0.045; postcontrast T1: 0.799 ± 0.054). There were strong correlations observed for T1 and λ derived from experts and FASTR (native T1: r = 0.83; postcontrast T1: r = 0.87; λ: r = 0.78; P < 0.0001), which were comparable to inter-expert correlation coefficients (native T1: r = 0.90; postcontrast T1: r = 0.93; λ: r = 0.80; P < 0.0001). CONCLUSIONS: Our fully automated framework, FASTR, can generate accurate myocardial segmentations for native and postcontrast MOLLI T1 analysis without the need for manual intervention. Such a design is appealing for high volume clinical protocols.


Assuntos
Infarto do Miocárdio , Miocárdio , Meios de Contraste , Coração/diagnóstico por imagem , Ventrículos do Coração/diagnóstico por imagem , Humanos , Imageamento por Ressonância Magnética , Imagem Cinética por Ressonância Magnética , Espectroscopia de Ressonância Magnética , Infarto do Miocárdio/diagnóstico por imagem , Valor Preditivo dos Testes , Reprodutibilidade dos Testes
8.
NMR Biomed ; 34(1): e4404, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-32875632

RESUMO

Hemorrhage is recognized as a new independent predictor of adverse outcomes following acute myocardial infarction. However, the mechanisms of its effects are less understood. The aim of our study was to probe the downstream impact of hemorrhage towards chronic remodeling, including inflammation, vasodilator function and matrix alterations in an experimental model of hemorrhage. Myocardial hemorrhage was induced in the porcine heart by intracoronary injection of collagenase. Animals (N = 18) were subjected to coronary occlusion followed by reperfusion in three groups (six/group): 8 min ischemia with hemorrhage (+HEM), 45 min infarction with no hemorrhage (I - HEM) and 45 min infarction with hemorrhage (I + HEM). MRI was performed up to 4 weeks after intervention. Cardiac function, edema (T2 , T1 ), hemorrhage (T2 *), vasodilator function (T2 BOLD), infarction and microvascular obstruction (MVO) and partition coefficient (pre- and post-contrast T1 ) were computed. Hemorrhage was induced only in the +HEM and I + HEM groups on Day 1 (low T2 * values). Infarct size was the greatest in the I + HEM group, while the +HEM group showed no observable infarct. MVO was seen only in the I + HEM group, with a 40% occurrence rate. Function was compromised and ventricular volume was enlarged only in the hemorrhage groups and not in the ischemia-alone group. In the infarct zone, edema and matrix expansion were the greatest in the I + HEM group. In the remote myocardium, T2 elevation and matrix expansion associated with a transient vasodilator dysfunction were observed in the hemorrhage groups but not in the ischemia-alone group. Our study demonstrates that the introduction of myocardial hemorrhage at reperfusion results in greater myocardial damage, upregulated inflammation, chronic adverse remodeling and remote myocardial alterations beyond the effects of the initial ischemic insult. A systematic understanding of the consequences of hemorrhage will potentially aid in the identification of novel therapeutics for high-risk patients progressing towards heart failure.


Assuntos
Hemorragia/diagnóstico por imagem , Hemorragia/fisiopatologia , Imageamento por Ressonância Magnética , Infarto do Miocárdio/diagnóstico por imagem , Infarto do Miocárdio/fisiopatologia , Oxigênio/sangue , Remodelação Ventricular/fisiologia , Animais , Feminino , Testes de Função Cardíaca , Hemorragia/patologia , Microvasos/diagnóstico por imagem , Microvasos/patologia , Infarto do Miocárdio/patologia , Suínos
10.
J Pediatr Surg ; 55(8): 1616-1620, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31500874

RESUMO

PURPOSE: To compare the efficacy of pathological markers like Interstitial cells of Cajal (ICC), neurons and Collagen to Muscle ratio (CM ratio), in predicting pyeloplasty outcomes. METHODS: Histological sections from 31 patients with UPJO were analyzed for ICC & neurons on immuno-histochemistry and CM ratio on Masson's trichrome staining. Post-operative outcomes were analyzed at 1-year follow up; expressed as excellent, moderate or mild improvement, static and deterioration based on the three factors: ultrasound grade, differential renal function and renogram drainage pattern. The pathological findings were correlated with clinical outcomes. RESULTS: The study group (n = 31) had a mean age 2.9 (0.6) years (M: F = 22:9). UPJ segment had significantly less ICC/neurons and more collagen compared to normal ureter (p = 0.001). Pathological parameters at the anastomosed end of ureter had a better correlation than those at UPJ with clinical outcome. CM ratio with a stronger correlation (r = - 0.94; p = 0.001) was a better predictor of prognosis than ICC (r = 0.76; p = 0.01) or neuron (r = 0.83; p = 0.01) density. ICC >10/HPF, neurons >6/HPF and CM ratio <1.2 at ureteric end anastomosed were predictors of success. CONCLUSIONS: CM ratio analysis at anastomosed ureter is a superior marker for predicting pyeloplasty outcomes. LEVEL OF EVIDENCE: Type 2: Development of diagnostic criteria in a consecutive series of patients.


Assuntos
Pelve Renal/cirurgia , Ureter/cirurgia , Obstrução Ureteral , Procedimentos Cirúrgicos Urológicos , Biomarcadores/análise , Criança , Pré-Escolar , Colágeno/análise , Feminino , Humanos , Células Intersticiais de Cajal/citologia , Masculino , Resultado do Tratamento , Obstrução Ureteral/epidemiologia , Obstrução Ureteral/patologia , Obstrução Ureteral/cirurgia
11.
Pediatr Dev Pathol ; 22(6): 558-565, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31315518

RESUMO

BACKGROUND: The exact etiology of ureteropelvic junction obstruction (UPJO) is unknown, and inadequate excision of the narrow segment has been proposed as a cause of failure in 5% to 7% of cases of pyeloplasty. AIMS: To study whether frozen section can be useful to detect normal ureter distal to UPJO during pyeloplasty. METHODS: Histological sections from 31 patients with UPJO were analyzed for collagen to muscle ratio (CMR) on conventional (formalin) and rapid (frozen section) Masson's trichrome staining. Pathological findings were correlated with postoperative outcomes analyzed at 1-year follow-up and expressed as excellent, moderate, or mild improvement, static and deterioration based on ultrasound grade, differential renal function, and renogram drainage pattern. RESULTS: There was a very strong positive correlation (r = .94; P = .001) between CMR by conventional and rapid frozen Masson's trichrome staining. There was a very strong negative correlation between pyeloplasty outcomes and CMR on conventional staining (r = -.94; P = .001) or rapid frozen Masson's trichrome staining (r = -.91; P = .001). Regression analysis revealed that a CMR of 1.2 or less (95% confidence interval: 1.9-0.7) was associated with a successful outcome. CONCLUSIONS: It is feasible to intraoperatively identify normal ureter distal to UPJO using CMR analysis on the novel rapid frozen section technique reported.


Assuntos
Secções Congeladas , Coloração e Rotulagem/métodos , Ureter/patologia , Obstrução Ureteral/patologia , Criança , Pré-Escolar , Feminino , Seguimentos , Humanos , Lactente , Cuidados Intraoperatórios , Masculino , Resultado do Tratamento , Ureter/cirurgia , Obstrução Ureteral/diagnóstico , Obstrução Ureteral/cirurgia
12.
Am J Cardiol ; 123(7): 1173-1179, 2019 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-30683420

RESUMO

Our aim was to evaluate the temporal changes in left ventricular (LV) diastolic filling in relation to other LV parameters using cardiac MRI (CMR) in patients with HER2 positive breast cancer receiving trastuzumab therapy. Fourty-one women with early stage HER2+ breast cancer underwent serial CMR (baseline, 6, 12, and 18 months) after initiation of trastuzumab therapy. A single, blinded observer measured LV parameters on de-identified CMRs in random order. Linear mixed models were used to investigate temporal changes. Compared to baseline, there were significant decreases in systolic function as measured by both left ventricular ejection fraction (LVEF) (p <0.001 at 6 and 12 months) and peak ejection rate corrected for end-diastolic volume (PER/LVEDV) (p = 0.008 at 6 months, p = 0.01 at 12 months). However, these differences were no longer significant at 18 months. In contrast, significant reductions in diastolic function as measured by LV peak filling rate corrected for end-diastolic volume (PFR/LVEDV) were observed at 6 months (p = 0.012), 12 months (p = 0.031), and up to 18 months (p = 0.034). There were no significant temporal changes in the time to peak filling rate corrected for cardiac cycle (TPF/RR). The reduction in PFR/LVEDV at 18 months was no longer significant when corrected for heart rate. In conclusion, there were significant subclinical deleterious effects on both LV systolic and diastolic function among patients receiving trastuzumab. While there was recovery in LV systolic function after therapy cessation at 18 months, reduction in PFR/LVEDV appeared to persist. Thus, diastolic dysfunction may serve as a marker of trastuzumab-induced cardiotoxicity that needs to be confirmed in a larger study.


Assuntos
Neoplasias da Mama/tratamento farmacológico , Ventrículos do Coração/diagnóstico por imagem , Imagem Cinética por Ressonância Magnética/métodos , Trastuzumab/efeitos adversos , Disfunção Ventricular Esquerda/fisiopatologia , Função Ventricular Esquerda/fisiologia , Pressão Ventricular/fisiologia , Antineoplásicos Imunológicos/efeitos adversos , Antineoplásicos Imunológicos/uso terapêutico , Neoplasias da Mama/diagnóstico , Diástole , Feminino , Seguimentos , Ventrículos do Coração/fisiopatologia , Humanos , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Prognóstico , Estudos Prospectivos , Volume Sistólico/fisiologia , Sístole , Trastuzumab/uso terapêutico , Disfunção Ventricular Esquerda/induzido quimicamente , Disfunção Ventricular Esquerda/diagnóstico , Função Ventricular Esquerda/efeitos dos fármacos
13.
J Cardiovasc Magn Reson ; 20(1): 45, 2018 07 02.
Artigo em Inglês | MEDLINE | ID: mdl-29961424

RESUMO

BACKGROUND: Following acute myocardial infarction (AMI), microvascular integrity and function may be compromised as a result of microvascular obstruction (MVO) and vasodilator dysfunction. It has been observed that both infarcted and remote myocardial territories may exhibit impaired myocardial blood flow (MBF) patterns associated with an abnormal vasodilator response. Arterial spin labeled (ASL) CMR is a novel non-contrast technique that can quantitatively measure MBF. This study investigates the feasibility of ASL-CMR to assess MVO and vasodilator response in swine. METHODS: Thirty-one swine were included in this study. Resting ASL-CMR was performed on 24 healthy swine (baseline group). A subset of 13 swine from the baseline group underwent stress ASL-CMR to assess vasodilator response. Fifteen swine were subjected to a 90-min left anterior descending (LAD) coronary artery occlusion followed by reperfusion. Resting ASL-CMR was performed post-AMI at 1-2 days (N = 9, of which 6 were from the baseline group), 1-2 weeks (N = 8, of which 4 were from the day 1-2 group), and 4 weeks (N = 4, of which 2 were from the week 1-2 group). Resting first-pass CMR and late gadolinium enhancement (LGE) were performed post-AMI for reference. RESULTS: At rest, regional MBF and physiological noise measured from ASL-CMR were 1.08 ± 0.62 and 0.15 ± 0.10 ml/g/min, respectively. Regional MBF increased to 1.47 ± 0.62 ml/g/min with dipyridamole vasodilation (P < 0.001). Significant reduction in MBF was found in the infarcted region 1-2 days, 1-2 weeks, and 4 weeks post-AMI compared to baseline (P < 0.03). This was consistent with perfusion deficit seen on first-pass CMR and with MVO seen on LGE. There were no significant differences between measured MBF in the remote regions pre and post-AMI (P > 0.60). CONCLUSIONS: ASL-CMR can assess vasodilator response in healthy swine and detect significant reduction in regional MBF at rest following AMI. ASL-CMR is an alternative to gadolinium-based techniques for assessment of MVO and microvascular integrity within infarcted, as well as salvageable and remote myocardium. This has the potential to provide early indications of adverse remodeling processes post-ischemia.


Assuntos
Circulação Coronária , Vasos Coronários/diagnóstico por imagem , Imagem Cinética por Ressonância Magnética/métodos , Microcirculação , Microvasos/diagnóstico por imagem , Infarto do Miocárdio/diagnóstico por imagem , Marcadores de Spin , Vasodilatação , Animais , Circulação Coronária/efeitos dos fármacos , Vasos Coronários/efeitos dos fármacos , Vasos Coronários/fisiopatologia , Dipiridamol/administração & dosagem , Modelos Animais de Doenças , Estudos de Viabilidade , Feminino , Microcirculação/efeitos dos fármacos , Microvasos/efeitos dos fármacos , Microvasos/fisiopatologia , Infarto do Miocárdio/fisiopatologia , Valor Preditivo dos Testes , Sus scrofa , Vasodilatação/efeitos dos fármacos , Vasodilatadores/administração & dosagem
14.
Magn Reson Med ; 80(5): 1922-1934, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-29656481

RESUMO

PURPOSE: Most MR-guided catheter-based procedures, and imaging of patients with implanted medical devices, are currently contraindicated due to a significant risk of heating associated with induced RF currents. The induced RF current produces a corresponding artifact which can be used to remotely characterize current and safely predict RF heating. Application of this remote technique in vivo to safely quantify RF heating risk may allow for execution of many scans currently contraindicated. Sources of phase other than induced RF current may present difficulty in practical in vivo. METHODS: A custom ultra-short echo time (UTE) sequence was developed to minimize unwanted phase contributions. A phantom experiment was performed to compare current characterization using a stock gradient-echo (GRE) sequence and the custom UTE sequence following calibration of the temperature measurement apparatus using a previously published heating prediction technique. Animal experiments were used to investigate the feasibility of using the UTE sequence to quantify RF heating. RESULTS: Current characterization and heating prediction with a stock GRE sequence was equivalent to that with the custom UTE sequence. Heating measurements and image-based predictions in animal experiments agreed within error in all experiments. CONCLUSION: Through comparison of measured heating and image-based prediction, feasibility of using a custom UTE sequence to quantify RF heating risk in vivo was demonstrated.


Assuntos
Temperatura Alta , Imageamento por Ressonância Magnética/métodos , Termometria/métodos , Animais , Artefatos , Temperatura Corporal , Procedimentos Endovasculares , Coração/diagnóstico por imagem , Humanos , Segurança do Paciente , Imagens de Fantasmas , Ondas de Rádio , Processamento de Sinais Assistido por Computador , Cirurgia Assistida por Computador , Suínos
15.
J Cardiovasc Magn Reson ; 20(1): 20, 2018 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-29544514

RESUMO

BACKGROUND: Radiofrequency (RF) ablation has become a mainstay of treatment for ventricular tachycardia, yet adequate lesion formation remains challenging. This study aims to comprehensively describe the composition and evolution of acute left ventricular (LV) lesions using native-contrast cardiovascular magnetic resonance (CMR) during CMR-guided ablation procedures. METHODS: RF ablation was performed using an actively-tracked CMR-enabled catheter guided into the LV of 12 healthy swine to create 14 RF ablation lesions. T2 maps were acquired immediately post-ablation to visualize myocardial edema at the ablation sites and T1-weighted inversion recovery prepared balanced steady-state free precession (IR-SSFP) imaging was used to visualize the lesions. These sequences were repeated concurrently to assess the physiological response following ablation for up to approximately 3 h. Multi-contrast late enhancement (MCLE) imaging was performed to confirm the final pattern of ablation, which was then validated using gross pathology and histology. RESULTS: Edema at the ablation site was detected in T2 maps acquired as early as 3 min post-ablation. Acute T2-derived edematous regions consistently encompassed the T1-derived lesions, and expanded significantly throughout the 3-h period post-ablation to 1.7 ± 0.2 times their baseline volumes (mean ± SE, estimated using a linear mixed model determined from n = 13 lesions). T1-derived lesions remained approximately stable in volume throughout the same time frame, decreasing to 0.9 ± 0.1 times the baseline volume (mean ± SE, estimated using a linear mixed model, n = 9 lesions). CONCLUSIONS: Combining native T1- and T2-based imaging showed that distinctive regions of ablation injury are reflected by these contrast mechanisms, and these regions evolve separately throughout the time period of an intervention. An integrated description of the T1-derived lesion and T2-derived edema provides a detailed picture of acute lesion composition that would be most clinically useful during an ablation case.


Assuntos
Edema Cardíaco/diagnóstico por imagem , Ventrículos do Coração/diagnóstico por imagem , Ventrículos do Coração/cirurgia , Imagem Cinética por Ressonância Magnética , Imagem por Ressonância Magnética Intervencionista/métodos , Ablação por Radiofrequência/métodos , Animais , Edema Cardíaco/etiologia , Edema Cardíaco/patologia , Edema Cardíaco/fisiopatologia , Ventrículos do Coração/patologia , Ventrículos do Coração/fisiopatologia , Modelos Animais , Valor Preditivo dos Testes , Ablação por Radiofrequência/efeitos adversos , Sus scrofa , Fatores de Tempo , Função Ventricular Esquerda
16.
Med Phys ; 45(4): 1577-1585, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29493810

RESUMO

PURPOSE: Myocardial infarct (MI) may consist of an infarct core (IC) and a heterogeneous, semi-viable border zone (BZ). Patients with chronic MI in the left ventricular (LV) myocardium are at increased risk of developing ventricular arrhythmias, and may therefore qualify for implantable cardioverter defibrillator (ICD) therapy. Indices based on MI mass, as determined by cardiac magnetic resonance (CMR) imaging, are shown to be sensitive in predicting adverse ventricular arrhythmic events. However, several factors, such as imaging technique and spatial resolution affect the accuracy of MI mass quantification. The aim of this study was to compare the MI masses determined by T1-mapping CMR techniques to those of conventional late Gadolinium-enhanced cardiac magnetic resonance (LGE-CMR) using inversion recovery fast gradient echo (IR-FGRE). We additionally aimed to investigate the effect of diminishing image resolution on quantification of the MI mass and its ability to predict appropriate ICD therapy. METHODS: Thirty-eight patients with known MI underwent acquisitions of three CMR imaging techniques: the multicontrast late enhancement (MCLE) and modified look-locker inversion recovery (MOLLI) T1-mapping techniques, and conventional inversion recovery fast gradient echo (IR-FGRE) about 20 min after double-dose injection of Gadolinium. We postprocessed images to quantify IC and BZ masses determined by each CMR technique using a full-width half-maximum (FWHM) approach in IR-FGRE images and a fuzzy c-means clustering algorithm for T1-mapping images. To determine the impact of spatial resolution in sensitivity of predicting ICD events, we artificially diminished resolution of MCLE images acquired from a separate group of 27 patients who had been followed up for ICD therapy and compared the MI masses estimated from the original and downsampled MCLE images. RESULTS: Twelve patients out of 27 (44%) received ICD therapy (i.e., one or more delivered shock) during the follow-up stage. Between each of the three imaging methods, IC masses were not significantly different. Conversely, BZ masses determined by MOLLI were larger compared to those determined by MCLE and IR-FGRE (P value = 0.0022 and 0.0003, respectively). The BZ masses determined by MCLE were not significantly different from those determined by IR-FGRE; however, BZ masses determined by the downsampled MCLE were significantly larger than those determined by IR-FGRE and original MCLE (P value = 0.0033 and 0.0003, respectively). The BZ mass estimated by original MCLE was larger in patients who had received ICD therapy compared to those who did not (P value = 0.044). However, when the spatial resolution of the MCLE images was diminished to that of MOLLI, BZ masses were not significantly different between patients with and without ICD therapy. CONCLUSIONS: While estimated IC masses were consistent among all three techniques, the estimated BZ masses were not consistent, especially when spatial resolution of images differed between the techniques. In particular, our study showed that diminished image resolution caused an increase in estimation of the BZ mass, likely due to partial volume effects, which led to a reduced sensitivity in the prediction of appropriate ICD therapy.


Assuntos
Desfibriladores Implantáveis , Imageamento por Ressonância Magnética , Infarto do Miocárdio/diagnóstico por imagem , Infarto do Miocárdio/terapia , Razão Sinal-Ruído , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Masculino , Pessoa de Meia-Idade
17.
J Clin Diagn Res ; 11(9): PC01-PC05, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29207771

RESUMO

INTRODUCTION: Genito Urinary Tuberculosis (GUTB) is a widespread disease seen in urology practice. The true incidence and prevalence of GUTB is difficult to estimate because a large number of patients remain asymptomatic. AIM: To recognize typical and atypical clinical and radiological features of tuberculosis and to emphasize the need for diagnosing GUTB early. MATERIALS AND METHODS: This was a retrospective study conducted in 110 cases of GUTB diagnosed and treated in two teaching institutions over a period of three years, from July 2002 to June 2005. A detailed history, thorough clinical examination, urine examination, culture for tubercle bacillus, imaging studies, cystoscopy and histological and serological examination were done to arrive at a diagnosis. RESULTS: Fifty six patients (51%) were in the age group of 21-40 years. The male: female ratio was 1.4: 1. Loin pain was the most common symptom observed in 27% of the patients. Intravenous Urogram (IVU) revealed non-visulalised kidney in 25 patients (23%), hydronephrosis or hydrouretero nephrosis in 34 patients (31%) and distortion, cavitation or scarring of the calyces in 16 patients (14.5%). Five of them had thimble bladder. In 14 patients, IVU appeared normal. About 28 patients (25%) were treated conservatively with anti tuberculosis therapy. Twenty one of them (19%) underwent Nephrectomy and 10 patients had reconstructive procedures. CONCLUSION: A peculiarity of most of our patients was a late presentation with advanced disease. Most patients were asymptomatic or ignorant. Slow but continuous infection causes a destruction of renal parenchyma and the healing process leads to renal parenchymal loss. If identified early and treated appropriately, GUTB is a curable condition.

18.
J Clin Diagn Res ; 11(8): PD01-PD02, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28969196

RESUMO

Gonadal vein aneurysm is a very rare anomaly and the aetiology is often unknown. Many factors have been said as contributory such as multiple pregnancies, multiple pelvic surgeries, pelvic tumours or pelvic congestion, but none of them have been strongly or closely associated with the lesion. Here, we present a case of left gonadal vein aneurysm in a female with its management. A 72-year-old, diabetic and hypertensive female presented with complaints of left loin pain. She is multiparous with four normal vaginal deliveries. On evaluation, she was diagnosed to have 4 cm left gonadal vein aneurysmal mass with internal thrombus causing hydronephrosis due to mass compression and perilesional adhesions. She underwent left gonadal vein aneurysm excision. Many treatment options are available such as endovascular- embolization/sclerotherapy. In the presence of thrombus and dense adhesions, as noted in our case, it is best to do open surgery for safety of the patient and obtain a good outcome.

19.
J Clin Diagn Res ; 11(4): PD05-PD06, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28571207

RESUMO

Paratesticular region is an obscure anatomical region that includes spermatic cord and its contents, tunica of the testes, epididymis and appendices of epididymis and testis. Paratesticular tumours may closely resemble and be clinically indistinguishable from testicular tumours, resulting in a diagnostic dilemma. Preoperative distinction between the benign and malignant paratesticular tumour is extremely difficult, resulting in difficulty in diagnosis and management. We hereby present a case of a 56-year-old male who reported with a painless bilateral scrotal mass and underwent surgical excision of the same. The final biopsy report was paratesticular leiomyoma. The main purpose of this manuscript is to emphasize on the fact that it is imperative for the treating urologists to be aware of such potentially benign rare entity. A high index of clinical suspicion is mandatory, as lack of knowledge about this condition would result in an unnecessary radical orchidectomy.

20.
J Clin Diagn Res ; 10(9): PC17-PC21, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27790510

RESUMO

INTRODUCTION: Supra-costal Percutaneous Nephrolithotomy (PCNL) procedure has now become an established standard of care in patients with renal stone disease, in terms of morbidity, stone clearance, duration of stay and shorter convalescence period. Gone are the days when supracostal punctures were considered to be associated with a high morbidity. With increased expertise gained in performing multiple punctures and further refinements in focusing techniques, more and more of these procedures are being performed with an intention to achieve a maximum stone clearance with least morbidity. AIM: To prospectively analyze the various factors that predict the safety, efficacy and stone clearance rate in patients who have undergo supracostal punctures for PCNL procedures. MATERIALS AND METHODS: Three hundred seventy six patients underwent PCNL for renal stones. Ninety two (n=92) of them needed supra-costal puncture. All patients were subdivided into groups 1 and 2 based on the size, location of the stone and the stone burden. In all, 132 tracts were established. RESULTS: About 83% of patients achieved a complete stone free rate after initial PCNL. Stones more than 3 centimeters were found to be associated with significant residual stones. Radio opacity under image intensifier also had a significant impact on the ultimate stone free status. About 23% of those (n=5/22) who needed longer duration of surgery had a clinically significant residual stones, needing ancillary procedures. Fifteen patients (16%) had complications related to the procedure, of which 13 were in group 1 (87%). High percentage of complications in patients with larger stone burden was found to be statistically significant. In about 76% (n=70), the procedure required only less than 90 minutes. Also, in those 22 patients in whom the duration of procedure exceeded 90 minutes, 12 of them had complications, with a p-value of <0.0001. CONCLUSION: Supra-costal punctures are safe and effective options in a selected group of patients. The overall results are almost on par with that of the infra costal punctures, with an acceptable morbidity.

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