Dual-energy computed tomography material decomposition improves prediction accuracy of hematoma expansion in traumatic intracranial hemorrhage.

OBJECTIVE: The angiographic spot sign (AS) on CT angiography (CTA) is known to be useful for predicting expansion in intracranial hemorrhage, but its use is limited due to its relatively low sensitivity. Recently, dual-energy computed tomography (DECT) has been shown to be superior in distinguishing between hemorrhage and iodine. This study aimed to evaluate the diagnostic performance of hematoma expansion (HE) using DECT AS in traumatic intracranial hemorrhage. METHODS: We recruited participants with intracranial hemorrhage confirmed via CTA for suspected traumatic cerebrovascular injuries. We evaluated AS on both conventional-like and fusion images of DECT. AS is grouped into three categories: intralesional enhancement without change, delayed enhancement (DE), and growing contrast leakage (GL). HE was evaluated by measuring hematoma size on DECT and follow-up CT. Logistic regression analysis was used to evaluate whether AS on fusion images was a significant risk factor for HE. Diagnostic accuracy was calculated, and the results from conventional-like and fusion images were compared. RESULTS: Thirty-nine hematomas in 24 patients were included in this study. Of these, 18 hematomas in 13 patients showed expansion on follow-up CT. Among the expanders, AS and GL on fusion images were noted in 13 and 5 hematomas, respectively. In non-expanders, 10 and 1 hematoma showed AS and GL, respectively. In the logistic regression model, GL on the fusion image was a significant independent risk factor for predicting HE. However, when AS was used on conventional-like images, no factors significantly predicted HE. In the receiver operating characteristic curve analysis, the area under the curve of AS on the fusion images was 0.71, with a sensitivity and specificity of 66.7% and 76.2%, respectively. CONCLUSIONS: GL on fusion images of DECT in traumatic intracranial hemorrhage is a significant independent radiologic risk factor for predicting HE. The AS of DECT fusion images has improved sensitivity compared to that of conventional-like images.

The clinical application of nigrosome 1 detection on high-resolution susceptibility-weighted imaging in the evaluation of suspected Parkinsonism: The real-world performance and pitfalls.

PURPOSE: To evaluate the real-world diagnostic performance of high-resolution susceptibility-weighted imaging (HR-SWI) and investigate whether the reader's predictions can be used to find cases where HR-SWI finding and final clinical diagnosis matched. METHODS: This retrospective study enrolled patients with suspected Parkinsonism (n = 48) or volunteers with other intracranial pathologies (n = 31) who underwent brain magnetic resonance imaging (MRI) including HR-SWI, which was used to evaluate nigrosome 1 (NG1). All patients with suspected Parkinsonism underwent N-3-fluoropropyl-2-carbomethoxy-3-4-iodophenyl nortropane (FP-CIT) positron emission tomography and a clinical diagnosis was made by a neurologist. The HR-SWI data were qualitatively analyzed by two independent reviewers. A consensus reading was performed and a diagnostic confidence score was assigned. According to final clinical diagnosis, diagnostic sensitivity, specificity, and accuracy were calculated. Receiver operating characteristic (ROC) curve analysis was used to examine whether the diagnostic confidence score could be used to identify HR-SWI finding-final clinical diagnosis matched cases. RESULTS: Of the 48 patients with suspected Parkinsonism, 31 were diagnosed with idiopathic Parkinson's disease, and three with multiple system atrophy. The remaining 14 patients were included in the disease control group. Of the 31 volunteers, 10 subjects were excluded due to possibility of nigrostriatal degeneration and finally 21 subjects were enrolled as controls with non-Parkinsonism pathology (non-PD control). After consensus reading, 25 subjects were classified as true positive and 28 as true negative, according to HR-SWI findings. The calculated diagnostic sensitivity, specificity, and accuracy were 73.5%, 80.0%, and 76.8%, respectively. With using diagnostic concordance score, the area under the ROC curve for the detection of concordance case was 0.83 (95% CI: 0.72-0.91, p < 0.05). CONCLUSION: The diagnostic performance of NG1 detection using HR-SWI with 3T MRI was within acceptable range. Using the reader's diagnostic confidence could be helpful to find cases which HR-SWI finding and final clinical conclusion match. So HR-SWI may be of added value in the evaluation of suspected Parkinsonism.

Symmetrical Curvilinear Cytotoxic Edema Along the Surface of the Brain Stem: A Probable New Magnetic Resonance Imaging Finding of Leptomeningeal Carcinomatosis.

Lung cancer is one of the most common neoplasms to appear leptomeningeal metastasis (LM). Contrast-enhanced magnetic resonance imaging (MRI) is better diagnostic choice for LM and usually shows focal nodular or diffuse linear enhancement on the leptomeninges along the sulci and tentorium in the brain. We experienced atypical 2 cases of lung cancer in patients who showed unusual brain MRI finding of symmetrical curvilinear or band-like, nonenhancing cytotoxic edema along the surface of the brain stem. This finding is unique and different from the general findings of leptomeningeal metastasis. This unique imaging finding of symmetric curvilinear nonenhancing cytotoxic edema along the brainstem is extremely rare and represents a new presentation of leptomeningeal carcinomatosis.

Magnetic Resonance Imaging and Computed Tomography of the Brain-50 Years of Innovation, With a Focus on the Future.

This review focuses specifically on the developments in brain imaging, as opposed to the spine, and specifically conventional, clinical, cross-sectional imaging, looking primarily at advances in magnetic resonance imaging (MRI) and computed tomography (CT). These fields are viewed from a perspective of landmark publications in the last 50 years and subsequently more in depth using sentinel publications from the last 5 years. It is also written from a personal perspective, with the authors having witnessed the evolution of both fields from their initial clinical introduction to their current state. Both CT and MRI have made tremendous advances during this time, regarding not only sensitivity and spatial resolution, but also in terms of the speed of image acquisition. Advances in CT in recent years have focused in part on reduced radiation dose, an important topic for the years to come. Magnetic resonance imaging has seen the development of a plethora of scan techniques, with marked superiority to CT in terms of tissue contrast due to the many parameters that can be assessed, and their intrinsic sensitivity. Future advances in MRI for clinical practice will likely focus both on new acquisition techniques that offer advances in speed and resolution, for example, simultaneous multislice imaging and data sparsity, and on standardization and further automation of image acquisition and analysis. Functional imaging techniques including specifically perfusion and functional magnetic resonance imaging will be further integrated into the workflow to provide pathophysiologic information that influence differential diagnosis, assist treatment decision and planning, and identify and follow treatment-related changes.

Sixth cranial nerve palsy caused by gastric adenocarcinoma metastasis to the clivus.

Tumors of the clivus and metastases to the clivus are very rare. Metastasis involving the clivus has previously been described in only two case reports. In skull metastasis, the breast and prostate are the most common primary foci, while metastasis from gastric carcinoma is extremely rare. A review of the English literature revealed only one published case of clivus metastases from gastric adenocarcinoma. There is no literature thoroughly explaining the differential diagnosis between chordoma and metastasis. Here we report a rare case of metastasis to the clivus from a gastric adenocarcinoma in a 42-year-old female patient with sudden blurry vision, presenting as bilateral cranial nerve VI palsy.

Solitary fibrous tumor of the post-styloid parapharyngeal space.

Solitary fibrous tumor (SFT) is a well-known tumor composed of spindle cells found most commonly in the pleura. Recently, accounts of their rare occurrence at other sites, including the head and neck area, have been reported. The parapharyngeal space is a rare location even for head and neck SFTs, and thus, could be confused with a variety of other tumors that can originate in this area. Here, we report a case of SFT originating from the post-styloid parapharyngeal space and discuss the possible differential diagnosis on radiographic findings.

Grading of cerebral glioma with multiparametric MR imaging and 18F-FDG-PET: concordance and accuracy.

OBJECTIVES: To retrospectively evaluate concordance rates and predictive values in concordant cases among multiparametric MR techniques and FDG-PET to grade cerebral gliomas. METHODS: Multiparametric MR imaging and FDG-PET were performed in 60 consecutive patients with cerebral gliomas (12 low-grade and 48 high-grade gliomas). As the dichotomic variables, conventional MRI, minimum apparent diffusion coefficient in diffusion-weighted imaging, maximum relative cerebral blood volume ratio in perfusion-weighted imaging, choline/creatine ratio and (lipid and lactate)/creatine ratio in MR spectroscopy, and maximum standardised uptake value ratio in FDG-PET in low- and high-grade gliomas were compared. Their concordance rates and positive/negative predictive values (PPV/NPV) in concordant cases were obtained for the various combinations of multiparametric MR techniques and FDG-PET. RESULTS: There were significant differences between low- and high-grade gliomas in all techniques. Combinations of two, three, four, and five out of the five techniques showed concordance rates of 77.0 ± 4.8%, 65.5 ± 4.0%, 58.3 ± 2.6% and 53.3%, PPV in high-grade concordant cases of 97.3 ± 1.7%, 99.1 ± 1.4%, 100.0 ± 0% and 100.0% and NPV in low-grade concordant cases of 70.2 ± 7.5%, 78.0 ± 6.0%, 80.3 ± 3.4% and 80.0%, respectively. CONCLUSION: Multiparametric MR techniques and FDG-PET have a concordant tendency in a two-tiered classification for the grading of cerebral glioma. If at least two examinations concordantly indicated high-grade gliomas, the PPV was about 95%. KEY POINTS: • Modern imaging techniques can help predict the aggressiveness of cerebral gliomas. • Multiparametric MRI and FDG-PET have a concordant tendency to grade cerebral gliomas. • Their high-grade concordant cases revealed at least 95 % positive predictive values. • Their low-grade concordant cases revealed about 70­80% negative predictive values.

True progression versus pseudoprogression in the treatment of glioblastomas: a comparison study of normalized cerebral blood volume and apparent diffusion coefficient by histogram analysis.

OBJECTIVE: The purpose of this study was to differentiate true progression from pseudoprogression of glioblastomas treated with concurrent chemoradiotherapy (CCRT) with temozolomide (TMZ) by using histogram analysis of apparent diffusion coefficient (ADC) and normalized cerebral blood volume (nCBV) maps. MATERIALS AND METHODS: Twenty patients with histopathologically proven glioblastoma who had received CCRT with TMZ underwent perfusion-weighted imaging and diffusion-weighted imaging (b = 0, 1000 sec/mm(2)). The corresponding nCBV and ADC maps for the newly visible, entirely enhancing lesions were calculated after the completion of CCRT with TMZ. Two observers independently measured the histogram parameters of the nCBV and ADC maps. The histogram parameters between the true progression group (n = 10) and the pseudoprogression group (n = 10) were compared by use of an unpaired Student's t test and subsequent multivariable stepwise logistic regression analysis to determine the best predictors for the differential diagnosis between the two groups. Receiver operating characteristic analysis was employed to determine the best cutoff values for the histogram parameters that proved to be significant predictors for differentiating true progression from pseudoprogression. Intraclass correlation coefficient was used to determine the level of inter-observer reliability for the histogram parameters. RESULTS: The 5th percentile value (C5) of the cumulative ADC histograms was a significant predictor for the differential diagnosis between true progression and pseudoprogression (p = 0.044 for observer 1; p = 0.011 for observer 2). Optimal cutoff values of 892 × 10(-6) mm(2)/sec for observer 1 and 907 × 10(-6) mm(2)/sec for observer 2 could help differentiate between the two groups with a sensitivity of 90% and 80%, respectively, a specificity of 90% and 80%, respectively, and an area under the curve of 0.880 and 0.840, respectively. There was no other significant differentiating parameter on the nCBV histograms. Inter-observer reliability was excellent or good for all histogram parameters (intraclass correlation coefficient range: 0.70-0.99). CONCLUSION: The C5 of the cumulative ADC histogram can be a promising parameter for the differentiation of true progression from pseudoprogression of newly visible, entirely enhancing lesions after CCRT with TMZ for glioblastomas.

Effect of delayed transit time on arterial spin labeling: correlation with dynamic susceptibility contrast perfusion magnetic resonance in moyamoya disease.

OBJECTIVES: Because arterial spin labeling (ASL) is completely noninvasive and provides absolute cerebral blood flow (CBF) information within a brief period, the technique has been increasingly used for patients with acute or chronic cerebrovascular disease. However, the effect of delayed transit time on ASL can generate errors in the quantitative estimation of CBF using ASL. Furthermore, in the clinical setting, in which transit time is uncertain, the variability of the transit time in patients reduces the validity of CBF on ASL images. Therefore, we evaluated the effect of delayed transit time on ASL images compared with dynamic susceptibility contrast (DSC) perfusion magnetic resonance (MR) in patients with moyamoya disease. MATERIALS AND METHODS: Arterial spin labeling and DSC perfusion MR images were acquired in 54 patients with moyamoya disease. Vascular territory and anatomical structure-based regions of interest (ROIs) were applied to the CBF and time-to-peak (TTP) maps from DSC and a CBF map using ASL. The change of the correlation coefficient (r) between normalized CBFs (nCBFs) from DSC and ASL was evaluated with categorization by the TTP. In addition, the dependence of the difference between the nCBF values from DSC and ASL on the TTP obtained using DSC was also analyzed. RESULTS: The nCBF values from DSC and ASL were strongly correlated (r = 0.877 and r = 0.867 for the internal carotid artery (ICA) and middle cerebral artery territory-based ROIs, respectively; P < 0.0002 for both; r = 0.783 for the anatomical structure-based ROIs; P < 0.0084). However, correlations between nCBFs from DSC and ASL tended to be weaker when the TTP increased, with recovery when the TTP was extremely delayed (>25 seconds). The TTP delay had a positive effect on the difference between the nCBF values from the DSC and ASL for the ICA territory-based and anatomical structure-based ROIs (standardized coefficients, 0.224 for the ICA territory-based ROIs; P = 0.0410; 0.189 for the anatomical structure-based ROIs; P < 0.0084). CONCLUSIONS: Our results demonstrate that the correlation between the CBF values from the ASL and DSC tends to be weaker when the transit time is more delayed, with the restoration of the strength of the correlation when the TTP is extremely delayed (>25 seconds). Understanding the effect of delayed transit time on the CBF from ASL perfusion MR in a clinical setting would facilitate the proper interpretation of ASL images.

Serial MR analysis of early permanent and transient ischemia in rats: diffusion tensor imaging and high b value diffusion weighted imaging.

OBJECTIVE: To evaluate the temporal evolution and diagnostic values of the diffusion tensor imaging (DTI) and the high b value diffusion weighted imaging (DWI) in the early permanent and transient cerebral ischemia. MATERIALS AND METHODS: For permanent or 30-minute transient-ischemia induced 30 rats, DTI and DWIs at both high b (b = 3000 s/mm(2)) and standard b value (b = 1000 s/mm(2)) were obtained at the following conditions: at 15, 30, 45, 60 minutes after the occlusion of what for hyperacute permanent ischemia; at 1, 3, 5, 7, 9 hours after the occlusion for acute permanent ischemia; and at 15 minutes before reperfusion, 0.5, 2.5, and 24 hours after reperfusion for transient ischemia. The diffusion parameters and their ratios were obtained and compared between different b values, and among different time points and groups, respectively. RESULTS: For both b values, the apparent diffusion coefficient (ADC) ratio decreased for first three hours, and then slightly increased until 9 hours after the occlusion during a gradual continuous increase of DWI signal intensity (SI) ratio, with excellent correlation between ADC ratios and DWI SI ratios. The DWI showed a higher contrast ratio, but the ADC map showed a lower contrast ratio for permanent ischemia at high b value than at standard b value. Fractional anisotropy (FA) increased for 1 hour, then gradually decreased until 9 hours after the occlusion in permanent ischemia and showed transient normalization and secondary decay along with change in ADC in transient ischemia. CONCLUSION: This study presents characteristic initial elevation and secondary decay of FA, higher contrast ratio of DWI, and lower contrast ratio of ADC map at high b value, in addition to the time evolutions of diffusion parameters in early permanent and transient ischemia.

Tumor blood flow from arterial spin labeling perfusion MRI: a key parameter in distinguishing high-grade gliomas from primary cerebral lymphomas, and in predicting genetic biomarkers in high-grade gliomas.

PURPOSE: To evaluate the usefulness of pseudo-continuous arterial spin labeling (pCASL) imaging in differentiating high-grade gliomas from lymphomas and in noninvasively predicting genetic biomarkers in high-grade gliomas. MATERIALS AND METHODS: Twelve glioblastoma multiforme (GBM), 3 anaplastic astrocytoma (AA), 5 recurred GBM, and 9 lymphoma patients underwent conventional MR and pCASL imaging. On pCASL perfusion map, mean absolute tumor blood flow (mTBF) was calculated from five regions of interest (ROIs) within the enhancing portion of the tumor. Relative TBF (rTBF = mTBF/mBFgm × 100) was also calculated. mTBF and rTBF of high-grade gliomas and lymphomas were compared using unpaired Student's t-test and receiver operating characteristic (ROC) analysis. Additionally, the association of TBF and six immunohistochemically confirmed genetic biomarkers was analyzed by Pearson correlation analysis in the group of high-grade gliomas. RESULTS: Both mTBF and rTBF of the high-grade gliomas were significantly higher than those of the lymphomas: 92.1 ± 34.7 versus 53.6 ± 30.5 mL/min/100 mg (P = 0.008) and 182.3 ± 69.5 versus 92.5 ± 44.9 (P = 0.002), respectively. Only epidermal growth factor receptor (EGFR) expression status showed a significant positive correlation with mTBF(P = 0.015) and rTBF(P = 0.007). CONCLUSION: pCASL imaging may facilitate differentiation of high-grade gliomas from lymphomas and prediction of EGFR expression status in high-grade gliomas.

Desmoid-type fibromatosis in the head and neck: CT and MR imaging characteristics.

INTRODUCTION: In the head and neck region, desmoid-type fibromatosis is an uncommon tumor, and the imaging features have not been well described. The purpose of this study was to describe imaging features with their pathologic correlation of desmoid-type fibromatosis in this region. METHODS: Computed tomographic (CT) and magnetic resonance (MR) images of nine consecutive patients (five women and four men; age range, 2-72 years; mean age, 28 years) with desmoid-type fibromatosis in the head and neck were retrospectively evaluated, focusing on lesion location, size, shape, presence of a rim of surrounding fat, CT attenuation, signal intensity, and enhancement characteristics on MR with pathologic correlation. RESULTS: Desmoid-type fibromatosis involved perivertebral space (n = 5) and carotid space (n = 1) in six adult patients. In three pediatric patients, the fibromatosis primarily involved submandibular space (n = 2) and masticator space (n = 1) with frequent invasion to the adjacent spaces (3/3). A mean greatest dimension of 5.8 cm, elongated shape (7/9), and rim of surrounding fat (8/9) were the common features of the desmoid-type fibromatosis. Tumors often showed iso (3/7) or high attenuation (3/7) on postcontrast CT, high signal intensity (6/9) on T2-weighted image, iso signal intensity (8/9) on T1-weighted image, and strong MR enhancement (8/9). Characteristic nonenhancing low signal intensity bands (8/9) on all MR sequences were well correlated with dense collagenous stroma. CONCLUSIONS: Desmoid-type fibromatosis in the head and neck of adults frequently involves perivertebral space. Along with various common imaging features, desmoid-type fibromatosis shows characteristic nonenhancing low signal intensity bands on MR images.

Primary intracerebral malignant fibrous histiocytoma: CT, MRI, and PET-CT findings.

Primary intracranial malignant fibrous histiocytoma (MFH) is an extremely rare entity. A few reported cases have been associated with factors such as a previous history of radiation therapy or surgical trauma. We report on a rare case of intracerebral MFH in a previously healthy 47-year-old man, which was initially presumed to be a high-grade glioma. Conventional as well as advanced magnetic resonance sequences, including diffusion-weighted image and perfusion-weighted image, were used in characterization of the mass.

Effect of carotid artery stenting on cerebral blood flow: evaluation of hemodynamic changes using arterial spin labeling.

INTRODUCTION: The purpose of this work was to quantitatively evaluate the hemodynamic changes after carotid artery stenting (CAS) by measuring cerebral blood flow (CBF) using arterial spin labeling (ASL). METHODS: Twenty sets of pre- and postprocedural CBF maps were acquired using ASL in patients who underwent CAS. Vascular territory- and anatomical structure-based regions of interest were applied to the CBF maps. Relative CBF (rCBF) was calculated by adjusting ipsilateral CBF with contralateral CBF. To assess the changes in rCBF after CAS (ΔrCBF), we calculated the following difference: [Formula: see text]. RESULTS: Postprocedural CBFs were significantly higher than preprocedural CBFs for internal carotid artery and middle cerebral artery territories (P < 0.05 in both). Postprocedural rCBFs were also significantly higher than preprocedural rCBFs for internal carotid artery and middle cerebral artery territories (P < 0.05 in both). Significant correlations were observed between preprocedural rCBF and ΔrCBF for the internal carotid artery and middle cerebral artery territories (r = -0.7211, P = 0.0003 and r = -0.6427, P = 0.0022, respectively). Areas in which the ΔrCBF values were >5.00 ml 100 g⁻¹ min⁻¹ were the precentral, postcentral, middle frontal, middle temporal (caudal), superior parietal, and angular gyri. CONCLUSIONS: ASL has potential as a noninvasive imaging tool for the quantitative evaluation of hemodynamic changes after CAS. CAS improves cerebral perfusion in patients with carotid artery stenosis, and patients with greater perfusion deficits prior to CAS have greater improvement in perfusion after CAS. In addition, eloquent areas show the greatest improvement in perfusion.

Correlation of apparent diffusion coefficient values measured by diffusion MRI and MGMT promoter methylation semiquantitatively analyzed with MS-MLPA in patients with glioblastoma multiforme.

PURPOSE: To retrospectively determine whether the apparent diffusion coefficient (ADC) values correlate with O(6)-methylguanine DNA methyltransferase (MGMT) promoter methylation semiquantitatively analyzed by methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) in patients with glioblastoma. MATERIALS AND METHODS: The study was approved by the Institutional Review Board and was Health Insurance Portability and Accountability Act (HIPAA) compliant. Newly diagnosed patients with glioblastoma (n = 26) were analyzed with an ADC histogram approach based on enhancing solid portion. The methylation status of MGMT promoter was assessed by methylation-specific polymerase chain reaction (MSP) and by MS-MLPA. MS-MLPA is a semiquantitative method that determines the methylation ratio. The Ki-67 labeling index was also analyzed. The mean and 5th percentile ADC values were correlated with MGMT promoter methylation status and Ki-67 labeling index using a linear regression model. Progression-free survival (PFS) was also correlated with the ADC values using Kaplan-Meier survival analysis. RESULTS: The mean methylation ratio was 0.21 ± 0.20. By MSP, there were 5 methylated and 21 unmethylated tumors. The mean ADC revealed a positive relationship with MGMT promoter methylation ratio (P = 0.015) and was also significantly different according to MSP-determined methylation status (P = 0.011). Median PFS was significantly related with methylation ratio (P = 0.017) and MSP-derived methylation status (P = 0.025). A positive relationship was demonstrated between PFS and the mean ADC value (P = 0.001). The 5th percentile ADC values showed a significant negative relationship with Ki-67 labeling index (P = 0.036). CONCLUSION: We found that ADC values were significantly correlated with PFS as well as with MGMT promoter methylation status. We believe that ADC values may merit further investigation as a noninvasive biomarker for predicting treatment response.

MR imaging findings of extraventricular neurocytoma: a series of ten patients confirmed by immunohistochemistry of IDH1 gene mutation.

BACKGROUND: Extraventricular neurocytomas (EVNs) are rare neuronal tumors included as neoplasms in the 2007 World Health Organization (WHO) classification of tumors of the CNS. Although a few case reports describing EVNs have been published, a systematic analysis of MR imaging findings of EVN has not been reported. Furthermore, imaging findings of IDH1 mutation-negative EVNs have not yet been reported. The aim of our study is to describe the MR imaging findings of IDH1 mutation-negative EVNs. METHODS: MR images of ten patients with pathologically confirmed IDH1 mutation-negative EVNs were retrospectively reviewed. Conventional MR imaging of ten EVNs were reviewed with emphasis on the location, signal intensities, patterns, and grades of enhancement as well as the presence/grade of peritumoral edema, intratumoral cyst, hemorrhage, and calcification. The study also reviewed the results of DWI (b = 1,000 s/mm(2), n = 7). RESULTS: Seven EVN cases were located in the cerebral hemisphere, and the remaining cases were in the cerebellum and thalamus. Of those in the cerebral hemisphere, five were cortically based tumors. The tumors showed no or mild peritumoral edema. Eight tumors were enhanced on the postcontrast T1WIs. An intratumoral cyst, hemorrhage, and calcification were detected in four, one, and two cases, respectively. On DWI, only one case showed a lower ADC value than the brain parenchyma. CONCLUSION: EVNs are usually cortically based infiltrative hemispheric tumors with contrast enhancement, higher ADC value, and sometimes small cystic component, but hardly show peritumoral edema or intratumoral hemorrhage. The differential diagnosis of these findings includes low-grade glioneuronal tumors and low-grade gliomas.

Histogram analysis of apparent diffusion coefficient map of standard and high B-value diffusion MR imaging in head and neck squamous cell carcinoma: a correlation study with histological grade.

RATIONALE AND OBJECTIVES: A histologic grade in head and neck squamous cell carcinoma (HNSCC) is clinically important because of its association with prognosis. The purpose of this study was to investigate the efficacy of histographic analysis of apparent diffusion coefficient (ADC) maps on the basis of the entire tumor volume in differentiating histologic grades in HNSCC at standard (b = 1000 s/mm(2)) and high (b = 2000 s/mm(2)) b values. MATERIALS AND METHODS: Fifty-four patients with HNSCC, including well-differentiated (WD; n = 35), moderately differentiated (MD; n = 13) and poorly differentiated (PD; n = 6) carcinomas, were retrospectively evaluated. ADC maps were obtained at two different b values (1000 and 2000 s/mm(2)) in each patient. Tumors were delineated on each slice of ADC maps, and data were collected to obtain a histogram for the entire tumor volume. Histographic parameters were calculated, including mean, standard deviation, kurtosis, skewness, and the ratio of the kurtosis measured at b values of 1000 and 2000 s/mm(2). These parameters were correlated with histologic grades. RESULTS: There was no significant correlation between tumor grades and histographic parameters obtained from ADC maps at b = 1000 s/mm(2). However, mean ADC at b = 2000 s/mm(2) was significantly higher in WD HNSCC (881 ± 131 × 10(-6) mm(2)/s) than in MD and PD HNSCC (770 ± 163 and 780 ± 158 × 10(-6) mm(2)/s, respectively) (P < .05). Kurtosis ratio was significantly higher in PD HNSCC (115 ± 10%) compared to WD and MD HNSCC (91 ± 21% and 86 ± 26%, respectively) (P < .05). Diagnostic accuracy was 100%, 76.9%, and 65.8% for PD, MD, and WD HNSCC, respectively. CONCLUSIONS: Histographic analysis of ADC maps on the basis of the entire tumor volume can be useful in differentiating histologic grades of HNSCC using mean ADC at b = 2000 s/mm(2) and kurtosis ratio.

Gliomas: Histogram analysis of apparent diffusion coefficient maps with standard- or high-b-value diffusion-weighted MR imaging--correlation with tumor grade.

PURPOSE: To explore the role of histogram analysis of apparent diffusion coefficient (ADC) maps based on entire tumor volume data in determining glioma grade and to evaluate the diagnostic performance of ADC maps at standard (1000 sec/mm(2)) and high (3000 sec/mm(2)) b values. MATERIALS AND METHODS: This retrospective study was approved by the institutional review board, and informed consent was waived. Twenty-seven patients with astrocytic tumors underwent diffusion-weighted magnetic resonance imaging with b values of 1000 and 3000 sec/mm(2), and the corresponding ADC maps were calculated (ADC(1000) and ADC(3000), respectively). Regions of interest containing the lesion were drawn on every section of the ADC map containing the tumor and were summated to derive volume-based data of the entire tumor. Histogram parameters were correlated with tumor grade by using repeated measurements analysis of variance, the Tukey-Kramer test for post hoc comparisons, and an unpaired Student t test. Receiver operating characteristic (ROC) curves were constructed to determine the optimum threshold for each histogram parameter, and sensitivity and specificity were assessed. RESULTS: Minimum ADC(1000) and ADC(3000) both decreased with increasing tumor grade. The 50th and 75th percentiles of cumulative ADC(1000) histograms showed significant differences between grades (P = .015 and .001, respectively), while the fifth and 75th percentiles of cumulative ADC(3000) histograms showed such differences (P = .015 and .014, respectively). Minimum ADC and the fifth percentile for both ADC(1000) (P < .001 and P = .024, respectively) and ADC(3000) (P < .001 and P = .001, respectively) proved to be significant histogram parameters for differentiating high- from low-grade gliomas. The diagnostic value of the parameters derived from ADC(1000) and ADC(3000) were compared, and a significant difference (0.202, P = .014) was found between the areas under the ROC curve of the fifth percentiles for ADC(1000) and ADC(3000). CONCLUSION: Histogram analysis of ADC maps based on entire tumor volume can be a useful tool for grading gliomas. The fifth percentile of the cumulative ADC histogram obtained at a high b value was the most promising parameter for differentiating high- from low-grade gliomas.

Papillary glioneuronal tumors: a review of clinicopathologic and molecular genetic studies.

This study was designed to evaluate 4 new cases of papillary glioneuronal tumors (PGNTs), 2 of which had atypical histologic features, provides extensive IHC characterization, performed comparative genomic hybridization in 2 of our cases, and reviews the recent literature. The study group comprised 3 women and 1 man, with ages ranging from 12 to 75 years. Patients presented with seizures (n = 3) or muscle spasm (n = 1), and the tumors were located in the supratentorial region of the brain (3 in the frontal and 1 in the parietotemporal lobe). The 2 atypical tumors showed a moderately high mitotic rate (4 and 7/10 HPF, each), vascular endothelial hyperplasia, and necrosis. Tumor cells expressed both neuronal and glial markers, but the degree of neuronal versus glial expression was varied. None of the tumors expressed p53, EGFR wild type/vIII, IDH1, or CD34; however, nestin, galectin-3, and S100 were positive in the tumor cells. No EGFR gene amplification or 1p/19q deletion was found by fluorescence in situ hybridization. Half of the cases revealed PTEN loss by immunohistochemistry, and MGMT methylation was positive in 3 cases by MGMT methylation-specific polymerase chain reaction. Ultrastructurally, either astrocytic or neuronal differentiation was observed, but we could not identify any hybrid cells. An array-based comparative genomic hybridization study revealed loss of 1q, 6p, 8p, 9p, 9q, and 16q and gain of 2q, 3p, 5q, 6p, 7q, 10q, 16q, 19p, and 22q in 2 cases simultaneously. The first patient, who underwent subtotal resection, died because of progression of the tumor within 9 months after surgery; however, 2 patients were symptom free and progression free at 34 and 48 months after gross total resection (the patient 2: plus radiotherapy, the patient 3: no adjuvant chemo- or radiotherapy). The last patient developed seizures after a long symptom-free period (40 mo) with no evidence of tumor recurrence. Our 4 new cases, in conjunction with the literature review, reinforce that PGNTs are tumors that usually occur in young adults (mean age, 24 y); they are most often cystic with a mural nodule or are cystic/solid, supratentorial, closely located with the ventricle, molecularly genetically different from astrocytic or oligodendroglial tumors, and indolent in behavior. Cases (2 of 4 in our study) with atypical histologic features or that occur in advanced age (75 y), and sporadic reports of histologically or biologically aggressive PGNTs, serve to remind pathologists that the full spectrum of PGNTs is as yet unknown.