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Introduction: The aim of the study was to report a rare case of lacrimal gland abscess. Case Presentation: A 47-year-old woman noticed upper eyelid swelling on the right side 1.5 months before referral to our service. Oral antibiotics were administered, based on the diagnosis of acute dacryoadenitis at another clinic. The symptom had once subsided 20 days later but recurred. On the first examination, the right upper eyelid was swollen with tenderness. The right lacrimal gland was palpable. Blood tests revealed positive proteinase 3-anti-neutrophil cytoplasmic antibody. T2-weighted magnetic resonance and diffusion-weighted images showed a high signal intensity lesion in an enlarged right lacrimal gland, while apparent diffusion coefficient map demonstrated the lesion with a low signal intensity. We started administration of intravenous antibiotics. Abscess drainage and lacrimal gland biopsy were performed 4 days after the first examination. Culture test of the abscess showed only 1 colony growth of Cutibacterium acnes. The specimen harvested from the lacrimal gland showed proliferation of fibrous connective tissue and infiltration of inflammatory cells without vasculitis. After the drainage, the swelling gradually subsided. Administration of antibiotics discontinued at 22 days of follow-up. At 4-month follow-up, the patient did not have any symptom related to the lacrimal gland abscess. Conclusion: The diffusion-weighted images and apparent diffusion coefficient map are helpful for the diagnosis of lacrimal gland abscess when the culture tests provide poor results.

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BACKGROUND AND PURPOSE: Dueto motion artifacts, optic nerve (ON) findings of idiopathic intracranial hypertension (IIH) can easily be overlooked on T2-weighted (T2w) turbo spin-echo sequence. This study aimed to investigate the contribution of the apparent diffusion coefficient (ADC) map derived from the interleaved multi-shot (IMS) echoplanar imaging (EPI) to the ON findings of IIH in children. METHODS: MRIs of 42 pediatric patients aged 3-17 years diagnosed with definite IIH according to modified Dandy criteria were retrospectively re-evaluated, between April 2018 and January 2021. Forty-two age- and sex-matched subjects with no IIH symptoms and reported as normal were included as a control group. RESULTS: ON sheath distance (ONSD) on the ADC map (p = .005) and vertical tortuosity (p = .030) were significant single MRI parameters for predicting IIH. Other single parameters were not statistically significant. Flattening of the posterior sclera (FPS) and ON protrusion (ONP) were observed on ADC maps more frequently than T2w (42.8% vs. 19% and 19% vs. 4.7%, respectively). From combined MRI parameters, the presence of at least one of ONP, FPS, or ONSD on ADC maps (p = .001) showed greater significance than the presence of T2w (p = .048). The predictive values of other MRI findings evaluated together were not statistically significant (p > .05). CONCLUSIONS: This study's results show that due to the short readout time and less sensitivity to motion, the ADC map obtained from IMS-EPI can contribute to orbital findings of IIH, in addition to T2w.

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OBJECTIVES: To validate prospectively the ADNEX magnetic resonance (MR) scoring system to assess adnexal masses and to evaluate a new, modified ADNEX MR scoring system that incorporates diffusion-weighted imaging (DWI) with apparent diffusion coefficient (ADC) mapping. METHODS: Between January 2015 and September 2018, 323 consecutive women with adnexal masses diagnosed on transvaginal ultrasound (TVS) underwent standardized MR imaging (MRI) including diffusion and dynamic contrast-enhanced sequences. Of these, 131 underwent subsequent surgery. For interpretation of the MRI examinations, we applied the five-category ADNEX MR scoring system, along with a modified scoring system including DWI with ADC mapping. For both scoring systems, a score was given for all adnexal masses. Histological diagnosis was considered as the gold standard and lesions were classified as benign or malignant. The difference between the predictive values for diagnosing malignancy of the classical and modified scoring systems was assessed on the basis of the areas under the receiver-operating-characteristics (AUC) curves. The sensitivity and specificity for diagnosing malignancy of each score were also calculated. RESULTS: Among the 131 women with adnexal mass(es) diagnosed on TVS who underwent MRI and subsequent surgery, the surgery revealed 161 adnexal masses in 126 women; five women had no mass. Histological examination confirmed 161 adnexal masses, of which all had been detected on MRI: 32 malignant tumors, 15 borderline tumors, which were classified as part of the malignant group (n = 47), and 114 benign lesions. The AUC for prediction of a malignant lesion was 0.938 (95% CI, 0.902-0.975) using the classical ADNEX MR scoring system and 0.974 (95% CI, 0.953-0.996) using the modified scoring system. Pairwise comparison of these AUCs revealed a significant difference (P = 0.0032). The sensitivity and specificity for diagnosing malignancy with an ADNEX MR score of 4 or more were 95.5% and 86.6%, respectively, using the classic scoring system, and 95.7% and 93.3%, respectively, using the modified scoring system. CONCLUSION: DWI with ADC mapping could be integrated into the ADNEX MR scoring system to improve specificity, thereby potentially optimizing clinical management by avoiding unnecessary surgery. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

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BACKGROUND: Saving the ischemic penumbra (IP) is key in treating acute ischemic stroke (AIS). We aim to investigate the value of the apparent diffusion coefficient (ADC) map based radiomics model in the identification of IP in AIS. METHODS: This study retrospectively analyzed the data of 241 patients with AIS involving the anterior cerebral circulation who were treated in our hospital within 24 h of stroke onset from January 2014 to October 2019. With the perfusion-weighted imaging (PWI)/diffusion-weighted imaging (DWI) mismatch model as the gold standard to determine whether IP exists, we divided patients into PWI/DWI mismatch (84 cases) and non-PWI/DWI mismatch (157 cases). Following the DWI high signal area, the region of interest (ROI) was drawn to the maximum level of the lesions on the ADC map, and a total of 896 features were extracted. Maximum correlation and minimum redundancy (mRMR) algorithm were applied to select the optimized features subsets, and then the least absolute shrinkage and selection operator (LASSO) were furtherly applied to select the best features to construct radiomics signature in predicting PWI/DWI mismatch. The performance of the model was evaluated using a receiver operating characteristic (ROC) curve. One hundred times internal cross-validation was applied to evaluate the stability of the model. The clinical value of the model was evaluated using decision curve analysis (DCA). RESULTS: Twenty-one features were finally selected to set up the radiomics model. In the training set, the area under the ROC curve (AUC) was 0.92, and the sensitivity, specificity, and accuracy were 0.93, 0.75, 0.82, respectively. In the validation set, the AUC was 0.90, and the sensitivity, specificity, and accuracy were 0.88, 0.74, 0.80, respectively. The average AUC of internal cross-validation for 100 times in the training set were 0.88 and 0.83 in the validation set. DCA shows that within the threshold range of 0.08 to 1.0, the model gains more net benefit. CONCLUSIONS: The radiomics model based on the ADC map can effectively determine the presence of IP in patients with AIS.

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STUDY DESIGN: Observational study. PURPOSE: To evaluate healthy volunteers and patients with spinal canal lesions using apparent diffusion coefficient (ADC) maps with diffusion-weighted imaging. OVERVIEW OF LITERATURE: Decompression surgery for lumbar spinal stenosis (LSS) is selected on the basis of subjective assessment and cross-sectional magnetic resonance imaging (MRI). However, there is no objective standard for this procedure. METHODS: We performed 3T MRI in 10 healthy volunteers and 13 patients with LSS. The ADC values in the spinal canal were evaluated at 46 vertebrae (L4/5 and L5/S1 for each participant), and the reduced and conventional fields of view were compared. RESULTS: The ADC values were 2.72±0.12 at L4/5 in healthy volunteers, 2.76±0.19 at L5/S1 in healthy volunteers, 1.77±0.58 at L4/5 in patients with LSS, and 2.35±0.29 at L5/S1 in patients with LSS. The ADC value at L4/5 in patients with LSS was significantly lower than that at L5/S1 in patients with LSS and that at L4/5 and L5/S1 in healthy volunteers (p <0.05). With an ADC cutoff value of 2.46 to identify LSS, this approach provided an area under the curve of 0.81, sensitivity of 0.92, and specificity of 0.76 (p <0.05). CONCLUSIONS: Preoperative examination using ADC maps permits visualization and quantification of spinal canal lesions, thus proving the utility of ADC maps in the selection of decompression surgery for LSS.

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It is thought that posterior reversible encephalopathy syndrome (PRES) is both clinically and radiologically reversible. However, its reversible nature has been challenged based on reports of permanent neurological impairments. The factors that predict the development of irreversible neurological impairment are still unclear. In the present study, we investigated clinical manifestations, laboratory findings, and neuroradiological images to identify predictors of functional outcomes in PRES. We investigated 23 PRES patients. Apparent diffusion coefficient (ADC) reduction was observed in 4 patients in the poor outcome group, whereas no patients presented ADC reduction in the favourable outcome group (p<0.01). Further studies are warranted to evaluate the association between ADC reduction and functional outcome after PRES.

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INTRODUCTION: An appropriate surgical approach for posterior fossa lesions is to start tumor removal from areas with a defined plane to where tumor is infiltrating the brainstem or peduncles. This surgical approach minimizes risk of damage to eloquent areas. Although magnetic resonance imaging (MRI) is the current standard preoperative imaging obtained for diagnosis and surgical planning of pediatric posterior fossa tumors, it offers limited information on the infiltrative planes between tumor and normal structures in patients with medulloblastomas. Because medulloblastomas demonstrate diffusion restriction on apparent diffusion coefficient map (ADC map) sequences, we investigated the role of ADC map in predicting infiltrative and non-infiltrative planes along the brain stem and/or cerebellar peduncles by medulloblastomas prior to surgery. METHODS: Thirty-four pediatric patients with pathologically confirmed medulloblastomas underwent surgical resection at our facility from 2004 to 2012. An experienced pediatric neuroradiologist reviewed the brain MRIs/ADC map, assessing the planes between the tumor and cerebellar peduncles/brain stem. An independent evaluator documented surgical findings from operative reports for comparison to the radiographic findings. The radiographic findings were statistically compared to the documented intraoperative findings to determine predictive value of the test in identifying tumor infiltration of the brain stem cerebellar peduncles. RESULTS: Twenty-six patients had preoperative ADC mapping completed and thereby, met inclusion criteria. Mean age at time of surgery was 8.3 ± 4.6 years. Positive predictive value of ADC maps to predict tumor invasion of the brain stem and cerebellar peduncles ranged from 69 to 88 %; negative predictive values ranged from 70 to 89 %. Sensitivity approached 93 % while specificity approached 78 %. CONCLUSIONS: ADC maps are valuable in predicting the infiltrative and non-infiltrative planes along the tumor and brain stem interface in medulloblastomas. Inclusion and evaluation of ADC maps in preoperative evaluation can assist in surgical resection planning in patients with medulloblastoma.

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AIM: The present study aimed to evaluate pathological features of hepatocellular carcinomas (HCC) appearing hypointense on the apparent diffusion coefficient (ADC) map, and to elucidate the association between the signal intensity on the ADC map and metastatic recurrences after hepatectomy. METHODS: In total, 52 consecutive patients with initial hypervascular HCC (solitary lesion ≤5 cm in diameter) without vascular invasion on imaging were examined by diffusion-weighted magnetic resonance imaging before hepatectomy. The signal intensities of HCC on the ADC map were visually compared with the surrounding liver and categorized as hypointense or non-hypointense. Intrahepatic metastatic recurrence was defined as more than three intrahepatic recurrences. RESULTS: The 52 HCC were evaluated as 26 hypointense and 26 non-hypointense tumors. No significant differences between the hypointense and non-hypointense groups were seen for age, sex, etiology, tumor size and tumor marker levels. However, in resected specimens, significant differences between the two groups were noted for histological grade and microscopic portal invasion. The percentages of poorly differentiated HCC and microscopic portal invasion in the hypointense group were significantly higher than those in the non-hypointense group. The cumulative 3-year metastatic recurrence rates of the hypointense and non-hypointense groups on the ADC map were 56% and 13% (P = 0.001), respectively. Multivariate analyses indicated that hypointensity on the ADC map was the only independent factor related to metastatic recurrence. CONCLUSION: Hypointense HCC on ADC mapping are characterized by poor histological differentiation and more frequent microscopic portal invasion, and are significantly associated with metastatic recurrences after hepatectomy.

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AIM: It has been reported that the apparent diffusion coefficient (ADC) value of hepatocellular carcinomas (HCC) on diffusion-weighted magnetic resonance imaging (MRI) is associated with their histological grade. The present study aimed to evaluate whether the signal intensity of small hypervascular HCC on the ADC map is related to the treatment outcome of radiofrequency ablation (RFA). METHODS: Between February 2008 and August 2012, 136 consecutive patients with initial small hypervascular HCC (≤3 tumors and ≤3 cm in diameter) were examined by diffusion-weighted MRI before RFA. The signal intensities of HCC on the ADC map were visually compared with the surrounding liver and categorized as hypointense and non-hypointense. Critical recurrence was defined as more than three intrahepatic recurrences, recurrence with vascular invasion, seeding, dissemination and/or extrahepatic metastasis. RESULTS: The median follow up was 619 days. The cumulative 2-year recurrence rates of the hypointense and non-hypointense on the ADC map groups were 79% and 50% (P < 0.001), respectively, with cumulative 2-year local recurrence rates of 18% and 7% (P = 0.014) and cumulative 2-year critical recurrence rates of 38% and 13% (P = 0.005), respectively. The cumulative 3-year survival rates were 60% and 82% (P = 0.007), respectively. On multivariate analysis, hypointensity on the ADC map was the strongest independent factor related to recurrence and survival after RFA. CONCLUSION: The signal intensity of HCC on the ADC map was strongly associated with outcome after RFA. These results suggest that treatment strategy should be determined carefully even for small HCC when they appear hypointense on the ADC map.

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It has been established that enhanced computed tomography (CT) and (99m) Tc-dimercaptosuccinic acid renal scintigraphy ((99m) Tc-DMSA scintigraphy) used in conjunction with single-photon emission CT is a useful tool for the diagnosis of acute pyelonephritis (APN). The utility of non-enhanced magnetic resonance imaging (MRI), however, has not been investigated extensively for the diagnosis of APN or renal abscess in children. We describe the case of a 23-month-old boy with suspected APN who received non-enhanced MRI. Whole body diffusion-weighted imaging (DWI) was used, and a background body-signal suppression sequence was applied. High-intensity focal lesions were identified on DWI and low-intensity lesions on the apparent diffusion coefficient map in the acute phase. This case suggested that non-enhanced MRI could be a useful tool for the diagnosis of APN in children, because it can avoid the risks of not only radiation exposure but also nephrogenic systemic fibrosis associated with gadolinium-based contrast agents, especially in infants.

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BACKGROUND: Acute cerebellitis with unilateral onset is rare, and magnetic resonance imaging (MRI) is a useful method for demonstrating cerebellar involvement. PATIENT: We report a 12-year-old girl with acute cerebellitis with a unique sequential change on her MRI. RESULTS: The patient's brain MRI first revealed cortical lesions mainly in the right cerebellar hemisphere. These subsequently disappeared, and at the same time, new lesions appeared in the opposite cerebellar hemisphere. All the lesions were confined to gray matter in the cerebellum and were isotense on diffusion-weighted imaging and had high signal intensity on the apparent diffusion coefficient map, consistent with the characteristic of vasogenic edema. CONCLUSION: The sequential MRI demonstrates conversion of hemicerebellitis to bilateral cerebellitis during subacute phase, and vasogenic edema might be contributing to the pathogenesis of acute cerebellitis in this patient.

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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.

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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.

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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.

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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.

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