The diagnostic value of diffusion-weighted magnetic resonance imaging and apparent diffusion coefficient values in children with cerebral infarction / 中国小儿急救医学

Objective To explore the diffusion-weighted magnetic resonance imaging (DWI) and apparent dispersion coefficient(ADC) value in cerebral infarction diagnosis and judgment of cerebral infarction outcome and staging of the value.Methods According to different stages,26 patients were divided into 3 phases,phase Ⅰ (6 ～72 h) had 11 cases,phase Ⅱ (4 ～ 10 d) had 12 cases,phase Ⅲ (10 d later) had 9 cases,of which 3 cases were reviewed,3 cases were recurrence of cerebral infarction.Each patient's MRI included T1 weighted imaging,T2 weighted imaging,DWI and ADC sequence scan image reconstruction,the ADC map obtained one regions of interest (ROI),and the mean ADC value of ROI were calculated,the average ADC value of the corresponding contralateral area were also calculated by the same method,and then the mean relative ADC value were calculated.Results DWI image of all cases showed high signal,11 cases showed high signal and 1 case showed low signal in phase Ⅱ.In phase Ⅲ,1 case showed normal signal and 1 case showed high signal,2 cases showed mixed signal,1 case were reduced,and the rest were all low signal.Compared with the contralateral corresponding region,the average ADC values were reduced in phase Ⅰ.The infarction average ADC values were 0.434 × 10 3mm2/s,0.653 × 10-3mm2/s,1.600 × 10-3mm2/s in phase Ⅰ,Ⅱ,Ⅲ respectively,and the average ADC values of contralateral corresponding region were 0.938 × 10-3 mm2/s,0.814 × 10-3 mm2/s,0.757 × 10-3 mm2/s respectively; the mean relative ADC values were (51.5 ±16.8)％,(79.2 ±30.0)％,(210.9 ±45.1)％ in phase Ⅰ,Ⅱ,Ⅲ respectively (P ＜ 0.05).Conclusion ADC value of cerebral lesions area and relative ADC value of the variation in time provides an objective basis for the diagnosis of DWI,contributes to timely and accurately determine the age of cerebral lesions and pathophysiology of the changes.

Clinical applications and characteristics of apparent diffusion coefficient maps for the brain of two dogs

Diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) mapping are functional magnetic resonance imaging techniques for detecting water diffusion. DWI and the ADC map were performed for intracranial lesions in two dogs. In necrotizing leukoencephalitis, cavitated lesions contained a hypointense center with a hyperintense periphery on DWI, and hyperintense signals on the ADC maps. In metastatic sarcoma, masses including a necrotic region were hypointense with DWI, and hyperintense on the ADC map with hyperintense perilesional edema on DWI and ADC map. Since DWI and ADC data reflect the altered water diffusion, they can provide additional information at the molecular level.

Diffusion in the head and neck: an assessment beyond the anatomy / Aplicações da técnica de difusão por RM em cabeça e pescoço: um olhar além da anatomia

DWI/ADC is a completely non-invasive technique that has been successfully conducted for many years in brain imaging and is currently being studied for the assessment of other organs, such as the abdomen and pelvis and in particular the head and neck structures. Even though DWI and the ADC measurement are able provide tissue information at the cellular level, most imaging centers have not yet adopted them as part of their routine evaluation of the head and neck. DWI has demonstrated usefulness to discriminate specific histological tumor types, especially to differentiate benign solid lesions from malignant masses, to evaluate lymph nodes, particularly to differentiate benign disease from malignancy, to differentiate postradiation changes from residual tumor and potentially to predict therapy success. Moreover DWI seems to be a safer and more affordable method considering the absence of radiation and to the higher cost of FDG-PET to localize tumors and to differentiate benign from malignant masses. Given all these advantages and strengths, DWI will certainly become part of the routine in the MR imaging of the head and neck.

DWI é uma técnica totalmente não invasiva que tem sido utilizada com sucesso por muitos anos em imagens do cérebro e recentemente incluída como parte da avaliação de outros sistemas, por exemplo, no abdome e pelve e na cabeça e pescoço. Apesar de a DWI e a medida dos valores de ADC serem capazes de fornecer informações de tipos histológicos específicos de tumores, a maioria dos centros de imagem ainda não os adotaram como parte da rotina na avaliação da cabeça e pescoço. A medida de ADC demonstrou ser útil para discriminar tipos específicos de tumores histológicos, especialmente para diferenciar lesões benignas sólidas de massas malignas, importante na avaliação de linfonodos cervicais, principalmente para diferenciar processos nodais benignos de malignos, para diferenciar as alterações pós-radioterapia de tumor residual e ter uso potencial para predizer sucesso terapêutico. Além disso, DWI/ADC parece ser um método mais seguro e mais acessível, considerando a ausência de radiação ionizante e ao maior custo do FDG-PET na localização de tumores e diferenciar massas benignas de malignas. Com todas essas vantagens e potencialidades, DWI/ADC certamente fará parte da rotina na avaliação por imagem da cabeça e pescoço.