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Objective@#This study aimed to validate the risk stratification system (RSS) and biopsy criteria for cervical lymph nodes (LNs) proposed by the Korean Society of Thyroid Radiology (KSThR). @*Materials and Methods@#This retrospective study included a consecutive series of preoperative patients with thyroid cancer who underwent LN biopsy, ultrasound (US), and computed tomography (CT) between December 2006 and June 2015. LNs were categorized as probably benign, indeterminate, or suspicious according to the current US- and CT-based RSS and the size thresholds for cervical LN biopsy as suggested by the KSThR. The diagnostic performance and unnecessary biopsy rates were calculated. @*Results@#A total of 277 LNs (53.1% metastatic) in 228 patients (mean age ± standard deviation, 47.4 years ± 14) were analyzed. In US, the malignancy risks were significantly different among the three categories (all P 5 mm LNs, P ≥ 0.177). The criteria covering only suspicious LNs showed higher specificity and lower unnecessary biopsy rates than the current criteria, while maintaining sensitivity in all imaging modalities. @*Conclusion@#Integrative evaluation of US and CT helps in reducing the proportion of indeterminate LNs and the malignancy risk among them. Nodal size did not affect the malignancy risk of LNs, and the addition of indeterminate LNs to biopsy candidates did not have an advantage in detecting LN metastases in all imaging modalities.
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Purpose@#This study evaluated thyroid cancer risk in a lung cancer screening population according to the presence of an incidental thyroid nodule (ITN) detected on low-dose chest computed tomography (LDCT). @*Methods@#Of 47,837 subjects who underwent LDCT, a lung cancer screening population according to the National Lung Screening Trial results was retrospectively enrolled. The prevalence of ITN on LDCT was calculated, and the ultrasonography (US)/fine-needle aspiration (FNA)–based risk of thyroid cancer according to the presence of ITN on LDCT was compared using the Fisher exact or Student t-test as appropriate. @*Results@#Of the 2,329 subjects (female:male=44:2,285; mean age, 60.9±4.9 years), the prevalence of ITN on LDCT was 4.8% (111/2,329). The incidence of thyroid cancer was 0.8% (18/2,329, papillary thyroid microcarcinomas [PTMCs]) and was higher in the ITN-positive group than in the ITN-negative group (3.6% [4/111] vs. 0.6% [14/2,218], P=0.009). Among the 2,011 subjects who underwent both LDCT and thyroid US, all risks were higher (P<0.001) in the ITNpositive group than in the ITN-negative group: presence of thyroid nodule on US, 94.1% (95/101) vs. 48.6% (928/1,910); recommendation of FNA according to the American Thyroid Association guideline and Korean Thyroid Imaging Reporting and Data System guideline, 41.2% (42/101) vs. 2.4% (46/1,910) and 39.6% (40/101) vs. 1.9% (37/1,910), respectively. @*Conclusion@#Despite a higher risk of thyroid cancer in the LDCT ITN-positive group than in the ITN-negative group in a lung cancer screening population, all cancers were PTMCs. A heavy smoking history may not necessitate thorough screening US for thyroid incidentalomas.
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Objective@#This study aimed to explore the myelin volume change in patients with mild traumatic brain injury (mTBI) with post-concussion syndrome (PCS) using a multidynamic multiecho (MDME) sequence and automatic whole-brain segmentation. @*Materials and Methods@#Forty-one consecutive mTBI patients with PCS and 29 controls, who had undergone MRI including the MDME sequence between October 2016 and April 2018, were included. Myelin volume fraction (MVF) maps were derived from the MDME sequence. After three dimensional T1-based brain segmentation, the average MVF was analyzed at the bilateral cerebral white matter (WM), bilateral cerebral gray matter (GM), corpus callosum, and brainstem. The Mann–Whitney U-test was performed to compare MVF and myelin volume between patients with mTBI and controls. Myelin volume was correlated with neuropsychological test scores using the Spearman rank correlation test. @*Results@#The average MVF at the bilateral cerebral WM was lower in mTBI patients with PCS (median [interquartile range], 25.2% [22.6%–26.4%]) than that in controls (26.8% [25.6%–27.8%]) (p = 0.004). The region-of-interest myelin volume was lower in mTBI patients with PCS than that in controls at the corpus callosum (1.87 cm3 [1.70–2.05 cm3 ] vs. 2.21 cm3 [1.86– 3.46 cm3 ]; p = 0.003) and brainstem (9.98 cm3 [9.45–11.00 cm3 ] vs. 11.05 cm3 [10.10–11.53 cm3 ]; p = 0.015). The total myelin volume was lower in mTBI patients with PCS than that in controls at the corpus callosum (0.45 cm3 [0.39–0.48 cm3 ] vs. 0.48 cm3 [0.45–0.54 cm3 ]; p = 0.004) and brainstem (1.45 cm3 [1.28–1.59 cm3 ] vs. 1.54 cm3 [1.42–1.67 cm3 ]; p = 0.042). No significant correlation was observed between myelin volume parameters and neuropsychological test scores, except for the total myelin volume at the bilateral cerebral WM and verbal learning test (delayed recall) (r = 0.425; p = 0.048). @*Conclusion@#MVF quantified from the MDME sequence was decreased at the bilateral cerebral WM in mTBI patients with PCS. The total myelin volumes at the corpus callosum and brainstem were decreased in mTBI patients with PCS due to atrophic changes.
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Cerebral small vessel disease (CSVD) includes vascular lesions detected on brain MRI, such as white matter hyperintensities, lacunar infarctions, microbleeds, or enlarged perivascular spaces. There is accumulating evidence that vascular changes may play an important role in development of Alzheimer’s disease (AD), and CSVD lesions detected on brain MRI were reported to be associated with β-amyloid and tau proteins accumulation. As the vascular contribution has therapeutic potential, it is important to understand the association of CSVD with AD and AD biomarkers. This review begins with a brief introduction of AD and AD biomarkers, explains the association between AD and vascular changes, and then details the pathogenesis and MR imaging findings of CSVD. Afterwards, we discuss the association of CSVD with AD and AD biomarkers.
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Objective@#We aimed to investigate whether repeated intravascular administration of iodinated contrast media (ICM) or gadolinium-based contrast agents (GBCAs) within a short interval was associated with an increased risk of post-contrast acute kidney injury (PC-AKI). @*Materials and Methods@#This retrospective study included 300 patients (mean age ± standard deviation, 68.5 ± 8.1 years; 131 male and 169 female) who had undergone at least one ICM-enhanced perfusion brain CT scan, had their baseline and follow-up serum creatinine levels available, and had not undergone additional contrast-enhanced examinations 72 hours before and after a time window of interest were included. The study population was divided into three groups: single-dose group and groups of patients who had received multiple contrast administrations in the time window of interest with the minimum contrast repeat interval either within 4 hours (0–4-hour group) or between 4 to 48 hours (4–48-hour group).Multivariable logistic regression analysis was conducted to evaluate the association between AKI and repeated ICM administrations. A similar supplementary analysis was performed including both ICM and GBCA. @*Results@#When ICM was only considered ignoring GBCA, among 300 patients, 207 patients received a single dose of ICM, 58 had repeated doses within 4 hours (0–4-hour group), and 35 patients had repeated doses between 4 to 48 hours (4–48-hour group). Most patients (> 95%) had a baseline estimated glomerular filtration rate (eGFR) of ≥ 30 mL/min/1.73 m2 . AKI occurred in 7.2%, 13.8%, and 8.6% of patients in the single-dose, 0–4-hour, and 4–48-hour groups, respectively. In the 0–4-hour and 4–48-hour groups, additional exposure to ICM was not associated with AKI after adjusting for comorbidities and nephrotoxic drugs (all p values > 0.05). @*Conclusion@#Repeated intravascular administrations of ICM within a short interval did not increase the risk of AKI in our study patients suspected of acute stroke with a baseline eGFR of ≥ 30 mL/min/1.73 m2 .
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Objective@#To develop a radiomics risk score based on dynamic contrast-enhanced (DCE) MRI for prognosis prediction in patients with glioblastoma. @*Materials and Methods@#One hundred and fifty patients (92 male [61.3%]; mean age ± standard deviation, 60.5 ± 13.5 years) with glioblastoma who underwent preoperative MRI were enrolled in the study. Six hundred and forty-two radiomic features were extracted from volume transfer constant (Ktrans), fractional volume of vascular plasma space (Vp), and fractional volume of extravascular extracellular space (Ve) maps of DCE MRI, wherein the regions of interest were based on both T1-weighted contrast-enhancing areas and non-enhancing T2 hyperintense areas. Using feature selection algorithms, salient radiomic features were selected from the 642 features. Next, a radiomics risk score was developed using a weighted combination of the selected features in the discovery set (n = 105); the risk score was validated in the validation set (n = 45) by investigating the difference in prognosis between the “radiomics risk score” groups. Finally, multivariable Cox regression analysis for progression-free survival was performed using the radiomics risk score and clinical variables as covariates. @*Results@#16 radiomic features obtained from non-enhancing T2 hyperintense areas were selected among the 642 features identified. The radiomics risk score was used to stratify high- and low-risk groups in both the discovery and validation sets (both p < 0.001 by the log-rank test). The radiomics risk score and presence of isocitrate dehydrogenase (IDH) mutation showed independent associations with progression-free survival in opposite directions (hazard ratio, 3.56; p = 0.004 and hazard ratio, 0.34; p = 0.022, respectively). @*Conclusion@#We developed and validated the “radiomics risk score” from the features of DCE MRI based on non-enhancing T2 hyperintense areas for risk stratification of patients with glioblastoma. It was associated with progression-free survival independently of IDH mutation status.
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Objective@#For an accurate dynamic contrast-enhanced (DCE) MRI analysis, exact baseline T1 mapping is critical. The purpose of this study was to compare the pharmacokinetic parameters of DCE MRI using synthetic MRI with those using fixed baseline T1 values. @*Materials and Methods@#This retrospective study included 102 patients who underwent both DCE and synthetic brain MRI. Two methods were set for the baseline T1: one using the fixed value and the other using the T1 map from synthetic MRI. The volume transfer constant (Ktrans ), volume of the vascular plasma space (vp), and the volume of the extravascular extracellular space (ve) were compared between the two methods. The interclass correlation coefficients and the Bland-Altman method were used to assess the reliability. @*Results@#In normal-appearing frontal white matter (WM), the mean values of Ktrans , ve, and vp were significantly higher in the fixed value method than in the T1 map method. In the normal-appearing occipital WM, the mean values of ve and vp were significantly higher in the fixed value method. In the putamen and head of the caudate nucleus, the mean values of Ktrans , ve, and vp were significantly lower in the fixed value method. In addition, the T1 map method showed comparable interobserver agreements with the fixed baseline T1 value method. @*Conclusion@#The T1 map method using synthetic MRI may be useful for reflecting individual differences and reliable measurements in clinical applications of DCE MRI.
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Objective@#Few attempts have been made to investigate the prognostic value of dynamic contrast-enhanced (DCE) MRI or dynamic susceptibility contrast (DSC) MRI of non-enhancing, T2-high-signal-intensity (T2-HSI) lesions of glioblastoma multiforme (GBM) in newly diagnosed patients. This study aimed to investigate the prognostic values of DCE MRI and DSC MRI parameters from non-enhancing, T2-HSI lesions of GBM. @*Materials and Methods@#A total of 76 patients with GBM who underwent preoperative DCE MRI and DSC MRI and standard treatment were retrospectively included. Six months after surgery, the patients were categorized into early progression (n = 15) and non-early progression (n = 61) groups. We extracted and analyzed the permeability and perfusion parameters of both modalities for the non-enhancing, T2-HSI lesions of the tumors. The optimal percentiles of the respective parameters obtained from cumulative histograms were determined using receiver operating characteristic (ROC) curve and univariable Cox regression analyses. The results were compared using multivariable Cox proportional hazards regression analysis of progression-free survival. @*Results@#The 95th percentile value (PV) of Ktrans, mean Ktrans, and median Ve were significant predictors of early progression as identified by the ROC curve analysis (area under the ROC curve [AUC] = 0.704, p = 0.005; AUC = 0.684, p = 0.021; and AUC = 0.670, p = 0.0325, respectively). Univariable Cox regression analysis of the above three parametric values showed that the 95th PV of Ktrans and the mean Ktrans were significant predictors of early progression (hazard ratio [HR] = 1.06, p = 0.009; HR = 1.25, p = 0.017, respectively). Multivariable Cox regression analysis, which also incorporated clinical parameters, revealed that the 95th PV of Ktrans was the sole significant independent predictor of early progression (HR = 1.062, p < 0.009). @*Conclusion@#The 95th PV of Ktrans from the non-enhancing, T2-HSI lesions of GBM is a potential prognostic marker for disease progression.
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Purpose@#To explore cerebrovascular reservoir (CVR) and arterial transit time (ATT) changes using acetazolamide-challenged multi-phase arterial spin labeling (MP-ASL) perfusion-weighted MRI in chronic cerebrovascular steno-occlusive disease. @*Materials and Methods@#This retrospective study enrolled patients with chronic steno-occlusion who underwent acetazolamide-challenged MP-ASL between June 2019 and October 2020.Cerebral blood flow, CVR, basal ATT, and ATT changes associated with severe stenosis, total occlusion, and chronic infarction lesions were compared. @*Results@#There were 32 patients (5 with bilateral steno-occlusion) in our study sample. The CVR was significantly reduced during total occlusion compared with severe stenosis (26.2% ± 28.8% vs. 41.4% ± 34.1%, respectively, p = 0.004). The ATT changes were not significantly different (p = 0.717). The CVR was marginally lower in patients with chronic infarction (29.6% ± 39.1% vs. 38.9% ± 28.7%, respectively, p = 0.076). However, the ATT was less shortened in pa-tients with chronic infarction (-54 ± 135 vs. -117 ± 128 ms, respectively, p = 0.013). @*Conclusion@#Acetazolamide-challenged MP-ASL provides an MRI-based CVR evaluation tool for chronic steno-occlusive disease.
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Purpose@#Mild cognitive impairment (MCI) is a prodromal stage of Alzheimer's disease (AD). Brain atrophy in this disease spectrum begins in the medial temporal lobe structure, which can be recognized by magnetic resonance imaging. To overcome the unsatisfactory inter-observer reliability of visual evaluation, quantitative brain volumetry has been developed and widely investigated for the diagnosis of MCI and AD. The aim of this study was to assess the prediction accuracy of quantitative brain volumetry using a fully automated segmentation software package, NeuroQuant®, for the diagnosis of MCI. @*Materials and Methods@#A total of 418 subjects from the Korean Brain Aging Study for Early Diagnosis and Prediction of Alzheimer’s Disease cohort were included in our study. Each participant was allocated to either a cognitively normal old group (n = 285) or an MCI group (n = 133). Brain volumetric data were obtained from T1-weighted images using the NeuroQuant software package. Logistic regression and receiver operating characteristic (ROC) curve analyses were performed to investigate relevant brain regions and their prediction accuracies. @*Results@#Multivariate logistic regression analysis revealed that normative percentiles of the hippocampus (P < 0.001), amygdala (P = 0.003), frontal lobe (P = 0.049), medial parietal lobe (P = 0.023), and third ventricle (P = 0.012) were independent predictive factors for MCI. In ROC analysis, normative percentiles of the hippocampus and amygdala showed fair accuracies in the diagnosis of MCI (area under the curve: 0.739 and 0.727, respectively). @*Conclusion@#Normative percentiles of the hippocampus and amygdala provided by the fully automated segmentation software could be used for screening MCI with a reasonable post-processing time. This information might help us interpret structural MRI in patients with cognitive impairment.
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Objective@#We aimed to investigate whether repeated intravascular administration of iodinated contrast media (ICM) or gadolinium-based contrast agents (GBCAs) within a short interval was associated with an increased risk of post-contrast acute kidney injury (PC-AKI). @*Materials and Methods@#This retrospective study included 300 patients (mean age ± standard deviation, 68.5 ± 8.1 years; 131 male and 169 female) who had undergone at least one ICM-enhanced perfusion brain CT scan, had their baseline and follow-up serum creatinine levels available, and had not undergone additional contrast-enhanced examinations 72 hours before and after a time window of interest were included. The study population was divided into three groups: single-dose group and groups of patients who had received multiple contrast administrations in the time window of interest with the minimum contrast repeat interval either within 4 hours (0–4-hour group) or between 4 to 48 hours (4–48-hour group).Multivariable logistic regression analysis was conducted to evaluate the association between AKI and repeated ICM administrations. A similar supplementary analysis was performed including both ICM and GBCA. @*Results@#When ICM was only considered ignoring GBCA, among 300 patients, 207 patients received a single dose of ICM, 58 had repeated doses within 4 hours (0–4-hour group), and 35 patients had repeated doses between 4 to 48 hours (4–48-hour group). Most patients (> 95%) had a baseline estimated glomerular filtration rate (eGFR) of ≥ 30 mL/min/1.73 m2 . AKI occurred in 7.2%, 13.8%, and 8.6% of patients in the single-dose, 0–4-hour, and 4–48-hour groups, respectively. In the 0–4-hour and 4–48-hour groups, additional exposure to ICM was not associated with AKI after adjusting for comorbidities and nephrotoxic drugs (all p values > 0.05). @*Conclusion@#Repeated intravascular administrations of ICM within a short interval did not increase the risk of AKI in our study patients suspected of acute stroke with a baseline eGFR of ≥ 30 mL/min/1.73 m2 .
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Objective@#To develop a radiomics risk score based on dynamic contrast-enhanced (DCE) MRI for prognosis prediction in patients with glioblastoma. @*Materials and Methods@#One hundred and fifty patients (92 male [61.3%]; mean age ± standard deviation, 60.5 ± 13.5 years) with glioblastoma who underwent preoperative MRI were enrolled in the study. Six hundred and forty-two radiomic features were extracted from volume transfer constant (Ktrans), fractional volume of vascular plasma space (Vp), and fractional volume of extravascular extracellular space (Ve) maps of DCE MRI, wherein the regions of interest were based on both T1-weighted contrast-enhancing areas and non-enhancing T2 hyperintense areas. Using feature selection algorithms, salient radiomic features were selected from the 642 features. Next, a radiomics risk score was developed using a weighted combination of the selected features in the discovery set (n = 105); the risk score was validated in the validation set (n = 45) by investigating the difference in prognosis between the “radiomics risk score” groups. Finally, multivariable Cox regression analysis for progression-free survival was performed using the radiomics risk score and clinical variables as covariates. @*Results@#16 radiomic features obtained from non-enhancing T2 hyperintense areas were selected among the 642 features identified. The radiomics risk score was used to stratify high- and low-risk groups in both the discovery and validation sets (both p < 0.001 by the log-rank test). The radiomics risk score and presence of isocitrate dehydrogenase (IDH) mutation showed independent associations with progression-free survival in opposite directions (hazard ratio, 3.56; p = 0.004 and hazard ratio, 0.34; p = 0.022, respectively). @*Conclusion@#We developed and validated the “radiomics risk score” from the features of DCE MRI based on non-enhancing T2 hyperintense areas for risk stratification of patients with glioblastoma. It was associated with progression-free survival independently of IDH mutation status.
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Objective@#For an accurate dynamic contrast-enhanced (DCE) MRI analysis, exact baseline T1 mapping is critical. The purpose of this study was to compare the pharmacokinetic parameters of DCE MRI using synthetic MRI with those using fixed baseline T1 values. @*Materials and Methods@#This retrospective study included 102 patients who underwent both DCE and synthetic brain MRI. Two methods were set for the baseline T1: one using the fixed value and the other using the T1 map from synthetic MRI. The volume transfer constant (Ktrans ), volume of the vascular plasma space (vp), and the volume of the extravascular extracellular space (ve) were compared between the two methods. The interclass correlation coefficients and the Bland-Altman method were used to assess the reliability. @*Results@#In normal-appearing frontal white matter (WM), the mean values of Ktrans , ve, and vp were significantly higher in the fixed value method than in the T1 map method. In the normal-appearing occipital WM, the mean values of ve and vp were significantly higher in the fixed value method. In the putamen and head of the caudate nucleus, the mean values of Ktrans , ve, and vp were significantly lower in the fixed value method. In addition, the T1 map method showed comparable interobserver agreements with the fixed baseline T1 value method. @*Conclusion@#The T1 map method using synthetic MRI may be useful for reflecting individual differences and reliable measurements in clinical applications of DCE MRI.
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Objective@#Few attempts have been made to investigate the prognostic value of dynamic contrast-enhanced (DCE) MRI or dynamic susceptibility contrast (DSC) MRI of non-enhancing, T2-high-signal-intensity (T2-HSI) lesions of glioblastoma multiforme (GBM) in newly diagnosed patients. This study aimed to investigate the prognostic values of DCE MRI and DSC MRI parameters from non-enhancing, T2-HSI lesions of GBM. @*Materials and Methods@#A total of 76 patients with GBM who underwent preoperative DCE MRI and DSC MRI and standard treatment were retrospectively included. Six months after surgery, the patients were categorized into early progression (n = 15) and non-early progression (n = 61) groups. We extracted and analyzed the permeability and perfusion parameters of both modalities for the non-enhancing, T2-HSI lesions of the tumors. The optimal percentiles of the respective parameters obtained from cumulative histograms were determined using receiver operating characteristic (ROC) curve and univariable Cox regression analyses. The results were compared using multivariable Cox proportional hazards regression analysis of progression-free survival. @*Results@#The 95th percentile value (PV) of Ktrans, mean Ktrans, and median Ve were significant predictors of early progression as identified by the ROC curve analysis (area under the ROC curve [AUC] = 0.704, p = 0.005; AUC = 0.684, p = 0.021; and AUC = 0.670, p = 0.0325, respectively). Univariable Cox regression analysis of the above three parametric values showed that the 95th PV of Ktrans and the mean Ktrans were significant predictors of early progression (hazard ratio [HR] = 1.06, p = 0.009; HR = 1.25, p = 0.017, respectively). Multivariable Cox regression analysis, which also incorporated clinical parameters, revealed that the 95th PV of Ktrans was the sole significant independent predictor of early progression (HR = 1.062, p < 0.009). @*Conclusion@#The 95th PV of Ktrans from the non-enhancing, T2-HSI lesions of GBM is a potential prognostic marker for disease progression.
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Purpose@#To explore cerebrovascular reservoir (CVR) and arterial transit time (ATT) changes using acetazolamide-challenged multi-phase arterial spin labeling (MP-ASL) perfusion-weighted MRI in chronic cerebrovascular steno-occlusive disease. @*Materials and Methods@#This retrospective study enrolled patients with chronic steno-occlusion who underwent acetazolamide-challenged MP-ASL between June 2019 and October 2020.Cerebral blood flow, CVR, basal ATT, and ATT changes associated with severe stenosis, total occlusion, and chronic infarction lesions were compared. @*Results@#There were 32 patients (5 with bilateral steno-occlusion) in our study sample. The CVR was significantly reduced during total occlusion compared with severe stenosis (26.2% ± 28.8% vs. 41.4% ± 34.1%, respectively, p = 0.004). The ATT changes were not significantly different (p = 0.717). The CVR was marginally lower in patients with chronic infarction (29.6% ± 39.1% vs. 38.9% ± 28.7%, respectively, p = 0.076). However, the ATT was less shortened in pa-tients with chronic infarction (-54 ± 135 vs. -117 ± 128 ms, respectively, p = 0.013). @*Conclusion@#Acetazolamide-challenged MP-ASL provides an MRI-based CVR evaluation tool for chronic steno-occlusive disease.
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Purpose@#Mild cognitive impairment (MCI) is a prodromal stage of Alzheimer's disease (AD). Brain atrophy in this disease spectrum begins in the medial temporal lobe structure, which can be recognized by magnetic resonance imaging. To overcome the unsatisfactory inter-observer reliability of visual evaluation, quantitative brain volumetry has been developed and widely investigated for the diagnosis of MCI and AD. The aim of this study was to assess the prediction accuracy of quantitative brain volumetry using a fully automated segmentation software package, NeuroQuant®, for the diagnosis of MCI. @*Materials and Methods@#A total of 418 subjects from the Korean Brain Aging Study for Early Diagnosis and Prediction of Alzheimer’s Disease cohort were included in our study. Each participant was allocated to either a cognitively normal old group (n = 285) or an MCI group (n = 133). Brain volumetric data were obtained from T1-weighted images using the NeuroQuant software package. Logistic regression and receiver operating characteristic (ROC) curve analyses were performed to investigate relevant brain regions and their prediction accuracies. @*Results@#Multivariate logistic regression analysis revealed that normative percentiles of the hippocampus (P < 0.001), amygdala (P = 0.003), frontal lobe (P = 0.049), medial parietal lobe (P = 0.023), and third ventricle (P = 0.012) were independent predictive factors for MCI. In ROC analysis, normative percentiles of the hippocampus and amygdala showed fair accuracies in the diagnosis of MCI (area under the curve: 0.739 and 0.727, respectively). @*Conclusion@#Normative percentiles of the hippocampus and amygdala provided by the fully automated segmentation software could be used for screening MCI with a reasonable post-processing time. This information might help us interpret structural MRI in patients with cognitive impairment.
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Objective@#This study aimed to investigate the blood-brain barrier (BBB) disruption in mild traumatic brain injury (mTBI) patients with post-concussion syndrome (PCS) using dynamic contrast-enhanced (DCE) magnetic resonance (MR) imaging and automatic whole brain segmentation. @*Materials and Methods@#Forty-two consecutive mTBI patients with PCS who had undergone post-traumatic MR imaging, including DCE MR imaging, between October 2016 and April 2018, and 29 controls with DCE MR imaging were included in this retrospective study. After performing three-dimensional T1-based brain segmentation with FreeSurfer software (Laboratory for Computational Neuroimaging), the mean Ktrans and vp from DCE MR imaging (derived using the Patlak model and extended Tofts and Kermode model) were analyzed in the bilateral cerebral/cerebellar cortex, bilateral cerebral/cerebellar white matter (WM), and brainstem. Ktrans values of the mTBI patients and controls were calculated using both models to identify the model that better reflected the increased permeability owing to mTBI (tendency toward higher Ktrans values in mTBI patients than in controls). The Mann-Whitney U test and Spearman rank correlation test were performed to compare the mean Ktrans and vp between the two groups and correlate Ktrans and vp with neuropsychological tests for mTBI patients. @*Results@#Increased permeability owing to mTBI was observed in the Patlak model but not in the extended Tofts and Kermode model. In the Patlak model, the mean Ktrans in the bilateral cerebral cortex was significantly higher in mTBI patients than in controls (p = 0.042). The mean vp values in the bilateral cerebellar WM and brainstem were significantly lower in mTBI patients than in controls (p = 0.009 and p = 0.011, respectively). The mean Ktrans of the bilateral cerebral cortex was significantly higher in patients with atypical performance in the auditory continuous performance test (commission errors) than in average or good performers (p = 0.041). @*Conclusion@#BBB disruption, as reflected by the increased Ktrans and decreased vp values from the Patlak model, was observed throughout the bilateral cerebral cortex, bilateral cerebellar WM, and brainstem in mTBI patients with PCS.
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Objective@#To evaluate the association of MRI features with the major genomic profiles and prognosis of World Health Organization grade III (G3) gliomas compared with those of glioblastomas (GBMs). @*Materials and Methods@#We enrolled 76 G3 glioma and 155 GBM patients with pathologically confirmed disease who had pretreatment brain MRI and major genetic information of tumors. Qualitative and quantitative imaging features, including volumetrics and histogram parameters, such as normalized cerebral blood volume (nCBV), cerebral blood flow (nCBF), and apparent diffusion coefficient (nADC) were evaluated. The G3 gliomas were divided into three groups for the analysis: with this isocitrate dehydrogenase (IDH)-mutation, IDH mutation and a chromosome arm 1p/19q-codeleted (IDHmut1p/19qdel), IDH mutation, 1p/19q-nondeleted (IDHmut1p/19qnondel), and IDH wildtype (IDHwt). A prediction model for the genetic profiles of G3 gliomas was developed and validated on a separate cohort. Both the quantitative and qualitative imaging parameters and progression-free survival (PFS) of G3 gliomas were compared and survival analysis was performed. Moreover, the imaging parameters and PFS between IDHwt G3 gliomas and GBMs were compared. @*Results@#IDHmut G3 gliomas showed a larger volume (p = 0.017), lower nCBF (p = 0.048), and higher nADC (p = 0.007) than IDHwt. Between the IDHmut tumors, IDHmut1p/19qdel G3 gliomas had higher nCBV (p = 0.024) and lower nADC (p = 0.002) than IDHmut1p/19qnondel G3 gliomas. Moreover, IDHmut1p/19qdel tumors had the best prognosis and IDHwt tumors had the worst prognosis among G3 gliomas (p < 0.001). PFS was significantly associated with the 95th percentile values of nCBV and nCBF in G3 gliomas. There was no significant difference in neither PFS nor imaging features between IDHwt G3 gliomas and IDHwt GBMs. @*Conclusion@#We found significant differences in MRI features, including volumetrics, CBV, and ADC, in G3 gliomas, according to IDH mutation and 1p/19q codeletion status, which can be utilized for the prediction of genomic profiles and the prognosis of G3 glioma patients. The MRI signatures and prognosis of IDHwt G3 gliomas tend to follow those of IDHwt GBMs.
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Objective@#To evaluate pharmacokinetic variables from contrast-enhancing lesions (CELs) and non-enhancing T2 high signal intensity lesions (NE-T2HSILs) on dynamic contrast-enhanced (DCE) magnetic resonance (MR) imaging for predicting progression-free survival (PFS) in glioblastoma (GBM) patients. @*Materials and Methods@#Sixty-four GBM patients who had undergone preoperative DCE MR imaging and received standard treatment were retrospectively included. We analyzed the pharmacokinetic variables of the volume transfer constant (Ktrans) and volume fraction of extravascular extracellular space within the CEL and NE-T2HSIL of the entire tumor. Univariate and multivariate Cox regression analyses were performed using preoperative clinical characteristics, pharmacokinetic variables of DCE MR imaging, and postoperative molecular biomarkers to predict PFS. @*Results@#The increased mean Ktrans of the CEL, increased 95th percentile Ktrans of the CELs, and absence of methylated O6- methylguanine-DNA methyltransferase promoter were relevant adverse variables for PFS in the univariate analysis (p = 0.041, p = 0.032, and p = 0.083, respectively). The Kaplan-Meier survival curves demonstrated that PFS was significantly shorter in patients with a mean Ktrans of the CEL > 0.068 and 95th percentile Ktrans of the CEL > 0.223 (log-rank p = 0.038 and p = 0.041, respectively). However, only mean Ktrans of the CEL was significantly associated with PFS (p = 0.024; hazard ratio, 553.08; 95% confidence interval, 2.27–134756.74) in the multivariate Cox proportional hazard analysis. None of the pharmacokinetic variables from NE-T2HSILs were significantly related to PFS. @*Conclusion@#Among the pharmacokinetic variables extracted from CELs and NE-T2HSILs on preoperative DCE MR imaging, the mean Ktrans of CELs exhibits potential as a useful imaging predictor of PFS in GBM patients.
ABSTRACT
Objective@#Proper management of lymph nodes (LNs) with ultrasonographic (US) indeterminate features in thyroid cancerpatients remains elusive. We aimed to evaluate the malignancy risk and US findings predictive of malignancy for USindeterminate LNs in preoperative thyroid cancer patients through node-by-node correlation. @*Materials and Methods@#A total of 348 LNs in 284 thyroid cancer patients, who underwent fine-needle aspiration or coreneedlebiopsy between December 2006 and June 2015, were included. We determined the malignancy risks for US probablybenign, indeterminate, and suspicious categories. For US indeterminate LNs, which had neither echogenic hilum nor hilarvascularity in the absence of any suspicious finding, US findings were compared between benign and metastatic LNs usingMann-Whitney U test and Fisher’s exact test. @*Results@#US imaging diagnoses were probably benign in 20.7% (n = 72) cases, indeterminate in 23.6% (n = 82), andsuspicious in 55.7% (n = 194). Malignancy risk of US indeterminate LNs (19.5% [16/82]) differed from those of the USprobably benign (2.8% [2/72]) (p = 0.002) and US suspicious LNs (78.4% [152/194]) (p < 0.001). Among US indeterminate LNs,there were no significant differences in short, long, and long-to-short diameter (L/S) ratios between benign and metastatic LNs(3.9 vs. 3.8 mm, p = 0.619; 7.3 vs. 7.3 mm, p = 0.590; 1.9 vs. 1.9, p = 0.652). @*Conclusion@#US indeterminate LNs were frequently encountered during preoperative evaluation and had intermediate malignancyrisk. Given the lack of discriminative power of size criteria and L/S ratio, clinical factors such as surgical strategy and nodesize should be considered for proper triage of US indeterminate LNs in thyroid cancer.