Differentiating primary CNS lymphoma from glioblastoma multiforme: assessment using arterial spin labeling, diffusion-weighted imaging, and ¹⁸F-fluorodeoxyglucose positron emission tomography

Role of contrast-free MR-perfusion in the diagnosis of potential epileptogenic foci in children with focal epilepsia

ASL (Arterial Spin Labeling) – a novel modality of MR angiography – is based on radio-frequency labeling of aqueous protons in the arterial blood; the method is used to monitor blood supply to  organs, including the brain. So far there has been little information on the use of ASL in children with focal epilepsy, especially in the pre-surgery period.

Aim:to evaluate the perfusion patterns in seizure-free children with drug resistant focal epilepsy (FE) using the ASL mode of MRI.

Materials and methods.We studied the ASL data of 54 (23-boys/31 girls) patients with FE  treated in the Dpt. of Neurology at the Russian State Children Hospital from 2015 to 2018. The  patients’ age varied from 4 months to 17 years. All images were produced with a 3T GE Discovery  750W system.

Results. We found several brain perfusion patterns in children with FE; among other factors, those patterns depended on the clinical status of the patient, i. e. the interictal period or the early post- seizure period. The main pattern of the interictal period was characterized by a focal decrease in  perfusion located around a structural focus identified on MRI scans. In the early post-seizure  period, there was an increase in the arterial perfusion in the area of a structural epileptogenic lesion.

Conclusion.ASL-MRI is an effective diagnostic method providing more information on children  with FE during their pre-surgery phase. The ASL modality needs further research to rationalize its wider use as a preferred diagnostic tool or as a combination with the more complex PET and SPECT.

[18F]Fludarabine-PET as a promising tool for differentiating CNS lymphoma and glioblastoma: Comparative analysis with [18F]FDG in human xenograft models

This paper investigated whether positron emission tomography (PET) imaging with [¹⁸F]fludarabine ([¹⁸F]FDB) can help to differentiate central nervous system lymphoma (CNSL) from glioblastoma (GBM), which is a crucial issue in the diagnosis and management of patients with these aggressive brain tumors. Multimodal analyses with [¹⁸F]fluorodeoxyglucose ([¹⁸F]FDG), magnetic resonance imaging (MRI) and histology have also been considered to address the specificity of [¹⁸F]FDB for CNSL. Methods: Nude rats were implanted with human MC116 lymphoma-cells (n = 9) or U87 glioma-cells (n = 4). Tumor growth was monitored by MRI, with T2-weighted sequence for anatomical features and T1-weighted with gadolinium (Gd) enhancement for blood brain barrier (BBB) permeability assessment. For PET investigation, [¹⁸F]FDB or [¹⁸F]FDG (~11 MBq) were injected via tail vein and dynamic PET images were acquired up to 90 min after radiotracer injection. Paired scans of the same rat with the two [¹⁸F]-labelled radiotracers were investigated. Initial volumes of interest were manually delineated on T2w images and set on co-registered PET images and tumor-to-background ratio (TBR) was calculated to semi-quantitatively assess the tracer accumulation in the tumor. A tile-based method for image analysis was developed in order to make comparative analysis between radiotracer uptake and values extracted from immunohistochemistry staining. Results: In the lymphoma model, PET time-activity curves (TACs) revealed a differential response of [¹⁸F]FDB between tumoral and healthy tissues with average TBR varying from 2.45 to 3.16 between 5 to 90 min post-injection. In contrast, [¹⁸F]FDG demonstrated similar uptake profiles for tumoral and normal regions with TBR varying from 0.84 to 1.06 between these two time points. In the glioblastoma (GBM) model, the average TBRs were from 2.14 to 1.01 for [¹⁸F]FDB and from 0.95 to 1.65 for [¹⁸F]FDG. Therefore, inter-model comparisons showed significantly divergent responses (p < 0.01) of [¹⁸F]FDB between lymphoma and GBM, while [¹⁸F]FDG demonstrated overlap (p = 0.04) between the groups. Tumor characterization with histology (based mainly on Hoechst and CD79), as well as with MRI was overall in better agreement with [¹⁸F]FDB-PET than [¹⁸F]FDG with regard to tumor selectivity. Conclusions: [¹⁸F]FDB-PET demonstrated considerably greater specificity for CNSL when compared to [¹⁸F]FDG. It also permitted a more precise definition of target volume compared to contrast-enhanced MRI. Therefore, the potential of [¹⁸F]FDB-PET to distinguish CNSL from GBM is quite evident and will be further investigated in humans.

Clinical PET/MRI: 2018 Update

OBJECTIVE

The purpose of this article is to provide an update on clinical PET/MRI, including current and developing clinical indications and technical developments.

CONCLUSION

PET/MRI is evolving rapidly, transitioning from a predominant research focus to exciting clinical practice. Key technical obstacles have been overcome, and further technical advances promise to herald significant advancements in image quality. Further optimization of protocols to address challenges posed by this hybrid modality will ensure the long-term success of PET/MRI.

The Role of Advanced Brain Tumor Imaging in the Care of Patients with Central Nervous System Malignancies

OPINION STATEMENT

T1-weighted post-contrast and T2-weighted fluid-attenuated inversion recovery (FLAIR) magnetic resonance imaging (MRI) constitute the gold standard for diagnosis and response assessment in neuro-oncologic patients but are limited in their ability to accurately reflect tumor biology and metabolism, particularly over the course of a patient's treatment. Advanced MR imaging methods are sensitized to different biophysical processes in tissue, including blood perfusion, tumor metabolism, and chemical composition of tissue, and provide more specific information on tissue physiology than standard MRI. This review provides an overview of the most common and emerging advanced imaging modalities in the field of brain tumor imaging and their applications in the care of neuro-oncologic patients.

Primary CNS Lymphomas: Challenges in Diagnosis and Monitoring

Primary Central Nervous System Lymphoma (PCNSL) is a rare neoplasm that can involve brain, eye, leptomeninges, and rarely spinal cord. PCNSL lesions most typically enhance homogeneously on T1-weighted magnetic resonance imaging (MRI) and appear T2-hypointense, but high variability in MRI features is commonly encountered. Neurological symptoms and MRI findings may mimic high grade gliomas (HGGs), tumefactive demyelinating lesions (TDLs), or infectious and granulomatous diseases. Advanced MRI techniques (MR diffusion, spectroscopy, and perfusion) and metabolic imaging, such as Fluorodeoxyglucose Positron Emission Tomography (FDG-PET) or amino acid PET (usually employing methionine), may be useful in distinguishing these different entities and monitoring the disease course. Moreover, emerging data suggest a role for cerebrospinal fluid (CSF) markers in predicting prognosis and response to treatments. In this review, we will address the challenges in PCNSL diagnosis, assessment of response to treatments, and evaluation of potential neurotoxicity related to chemotherapy and radiotherapy.

Differentiating between Glioblastoma and Primary CNS Lymphoma Using Combined Whole-tumor Histogram Analysis of the Normalized Cerebral Blood Volume and the Apparent Diffusion Coefficient

Purpose:

This study aimed to determine whether whole-tumor histogram analysis of normalized cerebral blood volume (nCBV) and apparent diffusion coefficient (ADC) for contrast-enhancing lesions can be used to differentiate between glioblastoma (GBM) and primary central nervous system lymphoma (PCNSL).

Methods:

From 20 patients, 9 with PCNSL and 11 with GBM without any hemorrhagic lesions, underwent MRI, including diffusion-weighted imaging and dynamic susceptibility contrast perfusion-weighted imaging before surgery. Histogram analysis of nCBV and ADC from whole-tumor voxels in contrast-enhancing lesions was performed. An unpaired t-test was used to compare the mean values for each type of tumor. A multivariate logistic regression model (LRM) was performed to classify GBM and PCNSL using the best parameters of ADC and nCBV.

Results:

All nCBV histogram parameters of GBMs were larger than those of PCNSLs, but only average nCBV was statistically significant after Bonferroni correction. Meanwhile, ADC histogram parameters were also larger in GBM compared to those in PCNSL, but these differences were not statistically significant. According to receiver operating characteristic curve analysis, the nCBV average and ADC 25th percentile demonstrated the largest area under the curve with values of 0.869 and 0.838, respectively. The LRM combining these two parameters differentiated between GBM and PCNSL with a higher area under the curve value (Logit (P) = −21.12 + 10.00 × ADC 25th percentile (10⁻³ mm²/s) + 5.420 × nCBV mean, P < 0.001).

Conclusion:

Our results suggest that whole-tumor histogram analysis of nCBV and ADC combined can be a valuable objective diagnostic method for differentiating between GBM and PCNSL.

18F-FDG PET/CT in immunocompetent patients with primary central nervous system lymphoma: Differentiation from glioblastoma and correlation with DWI

OBJECTIVES

¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) is useful for the detection of cancerous lesions, and FDG uptake is related to the apparent diffusion coefficient (ADC) derived from diffusion-weighted imaging (DWI) of extracranial tumors. The purpose of our study was to investigate the ability of FDG PET/CT in distinguishing primary central nervous system lymphoma (PCNSL) from glioblastoma multiforme (GBM) and to explore the relationship between ¹⁸F-FDG uptake and the ADC in patients with PCNSL.

METHODS

We reviewed 92 patients (40 with PCNSL and 52 with GBM) who underwent FDG PET/CT scans at disease onset. The maximum standardized uptake value (SUVmax), tumor to normal contralateral cortex activity (T/N) ratio, SUVmean, metabolic tumor volume (MTV), and total lesion glycolysis (TLG) of tumor lesions were calculated. Receiver operating characteristic (ROC) curves were generated to determine the diagnostic performance for FDG PET-related parameters to differentiate PCNSL from GBM. Twenty-eight patients with PCNSL (with 34 lesions) also underwent diffusion-weighted imaging. Pearson's correlation analysis was used to assess the relation between SUV- and ADC-derived parameters.

RESULTS

The SUVmax, T/N ratio, SUVmean, and TLG values were significantly higher in PCNSL than in GBM. Comparative ROC analysis indicated that the SUVmax had a greater area under the curve (AUC) of 0.910 than the T/N ratio (0.905, P = .85), SUVmean (0.836, P = .0006), or TLG (0.641, P < 0.0001). The T/N ratio had the highest specificity (94.23%) for differentiating PCNSL from GBM, while the SUVmax had the most optimal sensitivity (92.31%). Further combined analysis of the indices did not significantly improve the AUC. Moderate inverse correlations between the SUVmax, SUVmean, TLG, and the ADC ratio (rADC) were found in PCNSLs (r = -0.526, P = .002; r = -0.504, P = .004; and r = -0.483, P = .006; respectively).

CONCLUSIONS

The SUVmax and T/N ratio may be reliable measures for differentiating PCNSLs from GBMs. Additionally, FDG metabolism indices were inversely proportional to the rADCs of PCNSL lesions.

Challenges and prospects in the diagnosis and treatment of primary central nervous system lymphoma

Introduction: Primary central nervous system lymphoma (PCNSL) retains peculiar biological and clinical characteristics and a worse prognosis with respect to other comparable lymphomas. The need for high doses of chemotherapy to achieve valid drug concentrations in cerebral tissues and/or radiotherapy results in severe treatment-related toxicities, mainly neurologic, which are frequently as disabling as the disease itself.Areas covered: Several emerging combined therapies are addressed that focus on treating PCNSL. The prognosis has improved in the last years but several questions remain unanswered and the research of more effective therapies goes on. Information and data were obtained from direct authors' experience and a PubMed search of recent peer-reviewed original articles, review articles, and clinical guidelines.Expert commentary: The substantial progress observed in PCNSL has to be ascribed to a carefully combination of standard chemotherapeutic drugs. High-dose methotrexate-based polychemotherapy followed by mainteinance therapy offers one of the best chances to control the disease. Major issues that deserve many efforts by researchers are the definition of optimal consolidation treatment and a shared management of specific conditions such as elderly population and intra-ocular localization.

Measurement of the perfusion fraction in brain tumors with intravoxel incoherent motion MR imaging: validation with histopathological vascular density in meningiomas

OBJECTIVE

To evaluate the quantification performance of the perfusion fraction (f) measured with intravoxel incoherent motion (IVIM) MR imaging in a comparison with the histological vascular density in meningiomas.

METHODS

29 consecutive patients with meningioma (59.0 ± 16.8 years old, 8 males and 21 females) who underwent a subsequent surgical resection were examined with both IVIM imaging and a histopathological analysis. IVIM imaging was conducted using a single-shot SE-EPI sequence with 13 b-factors (0, 10, 20, 30, 50, 80, 100, 200, 300, 400, 600, 800, 1000 s mm^-2) at 3T. The perfusion fraction (f) was calculated by fitting the IVIM bi-exponential model. The 90-percentile f-value in the tumor region-of-interest (ROI) was defined as the maximum f-value (f-max). Histopathological vascular density (%Vessel) was measured on CD31-immunostainted histopathological specimens. The correlation and agreement between the f-values and %Vessel was assessed.

RESULTS

The f-max (15.5 ± 5.5%) showed excellent agreement [intraclass correlation coefficient (ICC) = 0.754] and a significant correlation (r = 0.69, p < 0.0001) with the %Vessel (12.9 ± 9.4%) of the tumors. The Bland-Altman plot analysis showed excellent agreement between the f-max and %Vessel (bias, -2.6%; 95% limits of agreement, from -16.0 to 10.8%). The f-max was not significantly different among the histological subtypes of meningioma.

CONCLUSION

An excellent agreement and a significant correlation were observed between the f-values and %Vessel. The f-value can be used as a noninvasive quantitative imaging measure to directly assess the vascular volume fraction in brain tumors. Advances in knowledge: The f-value measured by IVIM imaging showed a significant correlation and an excellent agreement with the histological vascular density in the meningiomas. The f-value can be used as a noninvasive and quantitative imaging measure to directly assess the volume fraction of capillaries in brain tumors.

Addition of Amide Proton Transfer Imaging to FDG-PET/CT Improves Diagnostic Accuracy in Glioma Grading: A Preliminary Study Using the Continuous Net Reclassification Analysis

BACKGROUND AND PURPOSE

Amide proton transfer imaging has been successfully applied to brain tumors, however, the relationships between amide proton transfer and other quantitative imaging values have yet to be investigated. The aim was to examine the additive value of amide proton transfer imaging alongside [¹⁸F] FDG-PET and DWI for preoperative grading of gliomas.

MATERIALS AND METHODS

Forty-nine patients with newly diagnosed gliomas were included in this retrospective study. All patients had undergone MR imaging, including DWI and amide proton transfer imaging on 3T scanners, and [¹⁸F] FDG-PET. Logistic regression analyses were conducted to examine the relationship between each imaging parameter and the presence of high-grade (grade III and/or IV) glioma. These parameters included the tumor-to-normal ratio of FDG uptake, minimum ADC, mean amide proton transfer value, and their combinations. In each model, the overall discriminative power for the detection of high-grade glioma was assessed with receiver operating characteristic curve analysis. Additive information from minimum ADC and mean amide proton transfer was also evaluated by continuous net reclassification improvement. P < .05 was considered significant.

RESULTS

Tumor-to-normal ratio, minimum ADC, and mean amide proton transfer demonstrated comparable diagnostic accuracy in differentiating high-grade from low-grade gliomas. When mean amide proton transfer was combined with the tumor-to-normal ratio, the continuous net reclassification improvement was 0.64 (95% CI, 0.036-1.24; P = .04) for diagnosing high-grade glioma and 0.95 (95% CI, 0.39-1.52; P = .001) for diagnosing glioblastoma. When minimum ADC was combined with the tumor-to-normal ratio, the continuous net reclassification improvement was 0.43 (95% CI, -0.17-1.04; P = .16) for diagnosing high-grade glioma, and 1.36 (95% CI, 0.79-1.92; P < .001) for diagnosing glioblastoma.

CONCLUSIONS

Addition of amide proton transfer imaging to FDG-PET/CT may improve the ability to differentiate high-grade from low-grade gliomas.

Therapy of primary CNS lymphoma: role of intensity, radiation, and novel agents

Primary central nervous system (CNS) lymphomas represent a subgroup of malignancies with specific characteristics, an aggressive course, and unsatisfactory outcome in contrast with other lymphomas comparable for tumor burden and histological type. Despite the high sensitivity to conventional chemotherapy and radiotherapy, remissions are frequently short lasting. Treatment efficacy is limited by several factors, including the biology and microenvironment of this malignancy and the "protective" effect of the blood-brain barrier, which limits the access of most drugs to the CNS. Patients who survive are at high risk of developing treatment-related toxicity, mainly disabling neurotoxicity, raising the question of how to balance therapy intensification with the control of side effects. Recent therapeutic progress and effective international cooperation have resulted in a significantly improved outcome over the past 2 decades, with a higher proportion of patients receiving treatment with curative intent. Actual front-line therapy consists of high-dose methotrexate-based polychemotherapy. Evidence supporting the addition of an alkylating agent and rituximab is growing, and a recent randomized trial demonstrated that the combination of methotrexate, cytarabine, thiotepa, and rituximab (MATRix regimen) is associated with a significantly better overall survival. Whole-brain irradiation and high-dose chemotherapy supported by autologous stem cell transplantation are 2 effective consolidation strategies in patients with a disease responsive to induction chemotherapy. Different strategies such as alkylating maintenance, conservative radiotherapy, and nonmyeloablative consolidation are being addressed in large randomized trials and a more accurate knowledge of the molecular and biological characteristics of this malignancy are leading to the development of target therapies in refractory/relapsing patients, with the overall aim to incorporate new active agents as part of first-line treatment. The pros and cons of these approaches together with the best candidates for each therapy are outlined in this article.

Correlation between arterial spin-labeling perfusion and histopathological vascular density of pediatric intracranial tumors

Traditional MRI methods for estimation of blood flow in brain tumors require high-flow injection of contrast agents through large-bore intravenous access, which limits their pediatric utility. In contrast, arterial spin-labeling (ASL) can be used without contrast media. This study aimed to evaluate the relationship between tumor blood flow (TBF) measured by ASL and histopathological vascular density in pediatric brain tumors. Nineteen consecutive children were evaluated (10 boys, 9 girls; median age: 6 years; 8 high-grade and 11 low-grade tumors). ASL was performed with a pseudocontinuous labeling time of 1650 ms and post-labeling delay of 1525 ms. The maximal absolute (aTBF) and relative (rTBF) tumor blood flows were measured. To evaluate the relative vascular area (%Vessel), the total stained vascular area was divided by the whole tissue area. Spearman's rank-order correlation, the Mann-Whitney U test, and receiver operating characteristic analysis were used for statistical analysis. The absolute and relative TBF rates were 4.9-92.9 mL/100 g/min and 0.17-3.59 mL/100 g/min, respectively. The %Vessel was 0.6-30.2%. The %Vessel showed a significant positive correlation with TBF (aTBF: r = 0.87, P < 0.0001; rTBF: r = 0.89, P < 0.0001). The TBF rate of high-grade tumors was significantly higher than that of low-grade tumors (aTBF: P = 0.0050, rTBF: P = 0.0036). The rTBF had the best diagnostic performance (area under the curve: 0.89). ASL perfusion imaging without contrast material can be used for accurate evaluation of histopathological vascular density and may be helpful for tumor grading in children.

Contribution of arterial spin-labelling MRI in a case with immune reconstitution inflammatory syndrome

Central nervous system immune reconstitution inflammatory syndrome (CNS-IRIS), which occurs most often in HIV-infected patients, is an exacerbation of inflammatory reactions related to opportunistic infections as well as primary CNS malignancies both of which mostly occur in HIV-infected patients. However, differential diagnoses are challenging both clinically and radiologically. We describe a patient with CNS-IRIS due to toxoplasmosis whose ¹¹C-methionine uptake suggested lymphoma but whose arterial spin-labelling MRI led to the correct diagnosis.

Neuroimaging in Central Nervous System Lymphoma

Primary central nervous system lymphoma (PCNSL) is a rare aggressive high-grade type of extranodal lymphoma. PCNSL can have a variable imaging appearance and can mimic other brain disorders such as encephalitis, demyelination, and stroke. In addition to PCNSL, the CNS can be secondarily involved by systemic lymphoma. Computed tomography and conventional MRI are the initial imaging modalities to evaluate these lesions. Recently, however, advanced MRI techniques are more often used in an effort to narrow the differential diagnosis and potentially inform diagnostic and therapeutic decisions.

The performance of MR perfusion-weighted imaging for the differentiation of high-grade glioma from primary central nervous system lymphoma: A systematic review and meta-analysis

It is always a great challenge to distinguish high-grade glioma (HGG) from primary central nervous system lymphoma (PCNSL). We conducted a meta-analysis to assess the performance of MR perfusion-weighted imaging (PWI) in differentiating HGG from PCNSL. The heterogeneity and threshold effect were evaluated, and the sensitivity (SEN), specificity (SPE) and areas under summary receiver operating characteristic curve (SROC) were calculated. Fourteen studies with a total of 598 participants were included in this meta-analysis. The results indicated that PWI had a high level of accuracy (area under the curve (AUC) = 0.9415) for differentiating HGG from PCNSL by using the best parameter from each study. The dynamic susceptibility-contrast (DSC) technique might be an optimal index for distinguishing HGGs from PCNSLs (AUC = 0.9812). Furthermore, the DSC had the best sensitivity 0.963 (95%CI: 0.924, 0.986), whereas the arterial spin-labeling (ASL) displayed the best specificity 0.896 (95% CI: 0.781, 0.963) among those techniques. However, the variability of the optimal thresholds from the included studies suggests that further evaluation and standardization are needed before the techniques can be extensively clinically used.

Diagnostic Accuracy of T1-Weighted Dynamic Contrast-Enhanced-MRI and DWI-ADC for Differentiation of Glioblastoma and Primary CNS Lymphoma

BACKGROUND AND PURPOSE

Glioblastoma and primary CNS lymphoma dictate different neurosurgical strategies; it is critical to distinguish them preoperatively. However, current imaging modalities do not effectively differentiate them. We aimed to examine the use of DWI and T1-weighted dynamic contrast-enhanced-MR imaging as potential discriminative tools.

MATERIALS AND METHODS

We retrospectively reviewed 18 patients with primary CNS lymphoma and 36 matched patients with glioblastoma with pretreatment DWI and dynamic contrast-enhanced-MR imaging. VOIs were drawn around the tumor on contrast-enhanced T1WI and FLAIR images; these images were transferred onto coregistered ADC maps to obtain the ADC and onto dynamic contrast-enhanced perfusion maps to obtain the plasma volume and permeability transfer constant. Histogram analysis was performed to determine the mean and relative ADC_mean and relative 90th percentile values for plasma volume and the permeability transfer constant. Nonparametric tests were used to assess differences, and receiver operating characteristic analysis was performed for optimal threshold calculations.

RESULTS

The enhancing component of primary CNS lymphoma was found to have significantly lower ADC_mean (1.1 × 10^-3 versus 1.4 × 10^-3; P < .001) and relative ADC_mean (1.5 versus 1.9; P < .001) and relative 90th percentile values for plasma volume (3.7 versus 5.0; P < .05) than the enhancing component of glioblastoma, but not significantly different relative 90th percentile values for the permeability transfer constant (5.4 versus 4.4; P = .83). The nonenhancing portions of glioblastoma and primary CNS lymphoma did not differ in these parameters. On the basis of receiver operating characteristic analysis, mean ADC provided the best threshold (area under the curve = 0.83) to distinguish primary CNS lymphoma from glioblastoma, which was not improved with normalized ADC or the addition of perfusion parameters.

CONCLUSIONS

ADC was superior to dynamic contrast-enhanced-MR imaging perfusion, alone or in combination, in differentiating primary CNS lymphoma from glioblastoma.

A meta-analysis of arterial spin labelling perfusion values for the prediction of glioma grade

AIM

To investigate the ability of arterial spin labelling (ASL) perfusion parameters to distinguish high-grade from low-grade gliomas.

MATERIALS AND METHODS

The PubMed and EMBASE databases were systematically searched for relevant articles published up to September 2015. Studies that evaluated both high- and low-grade gliomas using ASL were included. The random effect model was used to calculate the standardised mean difference (SMD) of maximum mean absolute tumour blood flow values (aTBF_max, aTBF_mean) and maximum mean relative tumour blood flow (rTBF_max, rTBF_mean) between high- and low-grade gliomas.

RESULTS

Nine studies encompassing 305 patients with high- and low-grade gliomas, met all inclusion and exclusion criteria and were included in the study. Compared with low-grade gliomas, high-grade gliomas had a significant increase in all ASL perfusion values: aTBF_max (SMD=0.70, 95% confidence interval [CI]: 0.22-1.19, p=0.0046); aTBF_mean (SMD=0.86, 95% CI: 0.2-1.52, p=0.01); rTBF_max (SMD=1.08, 95% CI: 0.54-1.63, p=0.0001) and rTBF_mean (SMD=0.88, 95% CI: 0.35-1.4, p=0.0011).

CONCLUSIONS

The current study results indicate that tumour blood flow from ASL differs significantly with respect to the glioma grade. Despite some limitations, there is evidence that ASL may be useful to distinguish high- and low-grade gliomas. Further larger-scale studies are necessary to examine the utility of ASL to distinguish tumour grade.

Differentiation of Glioblastoma from Brain Metastasis: Qualitative and Quantitative Analysis Using Arterial Spin Labeling MR Imaging

PURPOSE

To evaluate the diagnostic performance of cerebral blood flow (CBF) by using arterial spin labeling (ASL) perfusion magnetic resonance (MR) imaging to differentiate glioblastoma (GBM) from brain metastasis.

MATERIALS AND METHODS

The institutional review board of our hospital approved this retrospective study. The study population consisted of 128 consecutive patients who underwent surgical resection and were diagnosed as either GBM (n = 89) or brain metastasis (n = 39). All participants underwent preoperative MR imaging including ASL. For qualitative analysis, the tumors were visually graded into five categories based on ASL-CBF maps by two blinded reviewers. For quantitative analysis, the reviewers drew regions of interest (ROIs) on ASL-CBF maps upon the most hyperperfused portion within the tumor and upon peritumoral T2 hyperintensity area. Signal intensities of intratumoral and peritumoral ROIs for each subject were normalized by dividing the values by those of contralateral normal gray matter (nCBFintratumoral and nCBFperitumoral, respectively). Visual grading scales and quantitative parameters between GBM and brain metastasis were compared. In addition, the area under the receiver-operating characteristic curve was used to evaluate the diagnostic performance of ASL-driven CBF to differentiate GBM from brain metastasis.

RESULTS

For qualitative analysis, GBM group showed significantly higher grade compared to metastasis group (p = 0.001). For quantitative analysis, both nCBFintratumoral and nCBFperitumoral in GBM were significantly higher than those in metastasis (both p < 0.001). The areas under the curve were 0.677, 0.714, and 0.835 for visual grading, nCBFintratumoral, and nCBFperitumoral, respectively (all p < 0.001).

CONCLUSION

ASL perfusion MR imaging can aid in the differentiation of GBM from brain metastasis.

Cerebral blood flow laterality derived from arterial spin labeling as a biomarker for assessing the disease severity of parkinson's disease

PURPOSE

To evaluate cerebral blood flow (CBF) laterality derived from arterial spin labeling (ASL) in early-stage Parkinson's disease (PD) patients compared with those with advanced stages.

MATERIALS AND METHODS

Thirty-eight patients with PD (21 patients in early stages, 17 patients in advanced stages) were retrospectively studied. The CBF maps derived from 3T ASL data were co-registered to the corresponding 3DT1WI using SPM 12 software. Caudate nucleus (CN), putamen (PT), globus pallidus (GP), and thalamus (TH) were manually traced on the representative axial slices of 3DT1WI. CBF of the CN, PT, GP, and TH was measured using corresponding pixels on the co-registered CBF maps. A laterality index (LI) was calculated as the ratio of the contralateral CBF to primary affected side CBF. Each LI was compared between early and advanced stages of PD using the Mann-Whitney U-test. The LIs were also compared between each stage of PD.

RESULTS

In the CN, the LIs were significantly higher in early stages (mean LI ± SD, 95% confidence interval = 1.06 ± 0.14, 1.00-1.13) than in advanced stages (0.94 ± 0.14, 0.87-1.01; P < 0.05). We also observed a tendency toward decreased LIs with disease severity (1.10 ± 0.14, 0.99-1.21 for Hoehn and Yahr stage I; 1.04 ± 0.14, 0.92-1.12 for stage II; 0.96 ± 0.11, 0.89-1.10 for stage III; 0.93 ± 0.17, 0.81-1.05 for stage IV).

CONCLUSION

The evaluation of CBF laterality pattern in the CN using ASL may be useful for assessing the disease severity of PD patients.

LEVEL OF EVIDENCE

3 J. MAGN. RESON. IMAGING 2017;45:1821-1826.

Brain Tumors: An Update on Clinical PET Research in Gliomas

A previous review published in 2012 demonstrated the role of clinical PET for diagnosis and management of brain tumors using mainly FDG, amino acid tracers, and ¹⁸F-fluorothymidine. This review provides an update on clinical PET studies, most of which are motivated by prediction of prognosis and planning and monitoring of therapy in gliomas. For FDG, there has been additional evidence supporting late scanning, and combination with ¹³N ammonia has yielded some promising results. Large neutral amino acid tracers have found widespread applications mostly based on ¹⁸F-labeled compounds fluoroethyltyrosine and fluorodopa for targeting biopsies, therapy planning and monitoring, and as outcome markers in clinical trials. ¹¹C-alpha-methyltryptophan (AMT) has been proposed as an alternative to ¹¹C-methionine, and there may also be a role for cyclic amino acid tracers. ¹⁸F-fluorothymidine has shown strengths for tumor grading and as an outcome marker. Studies using ¹⁸F-fluorocholine (FCH) and ⁶⁸Ga-labeled compounds are promising but have not yet clearly defined their role. Studies on radiotherapy planning have explored the use of large neutral amino acid tracers to improve the delineation of tumor volume for irradiation and the use of hypoxia markers, in particular ¹⁸F-fluoromisonidazole. Many studies employed the combination of PET with advanced multimodal MR imaging methods, mostly demonstrating complementarity and some potential benefits of hybrid PET/MR.

Differentiation between Glioblastoma Multiforme and Primary Cerebral Lymphoma: Additional Benefits of Quantitative Diffusion-Weighted MR Imaging

The differentiation between glioblastoma multiforme (GBM) and primary cerebral lymphoma (PCL) is important because the treatments are substantially different. The purpose of this article is to describe the MR imaging characteristics of GBM and PCL with emphasis on the quantitative ADC analysis in the tumor necrosis, the most strongly-enhanced tumor area, and the peritumoral edema. This retrospective cohort study collected 104 GBM (WHO grade IV) patients and 22 immune-competent PCL (diffuse large B cell lymphoma) patients. All these patients had pretreatment brain MR DWI and ADC imaging. Analysis of conventional MR imaging and quantitative ADC measurement including the tumor necrosis (ADCn), the most strongly-enhanced tumor area (ADCt), and the peritumoral edema (ADCe) were done. ROC analysis with optimal cut-off values and area-under-the ROC curve (AUC) was performed. For conventional MR imaging, there are statistical differences in tumor size, tumor location, tumor margin, and the presence of tumor necrosis between GBM and PCL. Quantitative ADC analysis shows that GBM tended to have significantly (P<0.05) higher ADC in the most strongly-enhanced area (ADCt) and lower ADC in the peritumoral edema (ADCe) as compared with PCL. Excellent AUC (0.94) with optimal sensitivity of 90% and specificity of 86% for differentiating between GBM and PCL was obtained by combination of ADC in the tumor necrosis (ADCn), the most strongly-enhanced tumor area (ADCt), and the peritumoral edema (ADCe). Besides, there are positive ADC gradients in the peritumoral edema in a subset of GBMs but not in the PCLs. Quantitative ADC analysis in these three areas can thus be implemented to improve diagnostic accuracy for these two brain tumor types. The histological correlation of the ADC difference deserves further investigation.

Response Assessment in Neuro-Oncology working group and European Association for Neuro-Oncology recommendations for the clinical use of PET imaging in gliomas

This guideline provides recommendations for the use of PET imaging in gliomas. The review examines established clinical benefit in glioma patients of PET using glucose ((18)F-FDG) and amino acid tracers ((11)C-MET, (18)F-FET, and (18)F-FDOPA). An increasing number of studies have been published on PET imaging in the setting of diagnosis, biopsy, and resection as well radiotherapy planning, treatment monitoring, and response assessment. Recommendations are based on evidence generated from studies which validated PET findings by histology or clinical course. This guideline emphasizes the clinical value of PET imaging with superiority of amino acid PET over glucose PET and provides a framework for the use of PET to assist in the management of patients with gliomas.

Evaluation of glioblastomas and lymphomas with whole-brain CT perfusion: Comparison between a delay-invariant singular-value decomposition algorithm and a Patlak plot

OBJECTIVE

Correction of contrast leakage is recommended when enhancing lesions during perfusion analysis. The purpose of this study was to assess the diagnostic performance of computed tomography perfusion (CTP) with a delay-invariant singular-value decomposition algorithm (SVD+) and a Patlak plot in differentiating glioblastomas from lymphomas.

MATERIALS AND METHODS

This prospective study included 17 adult patients (12 men and 5 women) with pathologically proven glioblastomas (n=10) and lymphomas (n=7). CTP data were analyzed using SVD+ and a Patlak plot. The relative tumor blood volume and flow compared to contralateral normal-appearing gray matter (rCBV and rCBF derived from SVD+, and rBV and rFlow derived from the Patlak plot) were used to differentiate between glioblastomas and lymphomas. The Mann-Whitney U test and receiver operating characteristic (ROC) analyses were used for statistical analysis.

RESULTS

Glioblastomas showed significantly higher rFlow (3.05±0.49, mean±standard deviation) than lymphomas (1.56±0.53; P<0.05). There were no statistically significant differences between glioblastomas and lymphomas in rBV (2.52±1.57 vs. 1.03±0.51; P>0.05), rCBF (1.38±0.41 vs. 1.29±0.47; P>0.05), or rCBV (1.78±0.47 vs. 1.87±0.66; P>0.05). ROC analysis showed the best diagnostic performance with rFlow (Az=0.871), followed by rBV (Az=0.771), rCBF (Az=0.614), and rCBV (Az=0.529).

CONCLUSION

CTP analysis with a Patlak plot was helpful in differentiating between glioblastomas and lymphomas, but CTP analysis with SVD+ was not.

CGCG clinical practice guidelines for the management of adult diffuse gliomas

The Chinese Glioma Cooperative Group (CGCG) Guideline Panel for adult diffuse gliomas provided recommendations for diagnostic and therapeutic procedures. The Panel covered all fields of expertise in neuro-oncology, i.e. neurosurgeons, neurologists, neuropathologists, neuroradiologists, radiation and medical oncologists and clinical trial experts. The task made clearer and more transparent choices about outcomes considered most relevant through searching the references considered most relevant and evaluating their value. The scientific evidence of papers collected from the literature was evaluated and graded based on the Oxford Centre for Evidence-based Medicine Levels of Evidence and recommendations were given accordingly. The recommendations will provide a framework and assurance for the strategy of diagnostic and therapeutic measures to reduce complications from unnecessary treatment and cost. The guideline should serve as an application for all professionals involved in the management of patients with adult diffuse glioma and also as a source of knowledge for insurance companies and other institutions involved in the cost regulation of cancer care in China.

Arterial Spin Labeling Techniques 2009-2014

PURPOSE

Arterial spin labeling (ASL) techniques have been implemented across a diverse range of clinical and experimental applications. This review aims to evaluate the current feasibility of ASL in clinical neuroradiology based on recent improvements to ASL sequences and highlight areas for potential clinical applications.

METHODS AND MATERIALS

In December 2014, a literature search was conducted on PubMed Central, EMBASE, and Scopus using the search terms: "arterial spin labeling, neuroradiology," for studies published between 2009 and 2014 (inclusive). Of 483 studies matching the inclusion criteria, the number of studies using continuous, pseudocontinuous, pulsed, and velocity-selective ASL sequences was 42, 209, 226, and 3, respectively. Studies were classified based on several common clinical applications according to the type of ASL sequence used. Studies using pulsed ASL and pseudo-continuous ASL were grouped based on common sequences.

RESULTS

The number of clinical studies was 264. Numerous studies applied ASL to stroke management (43 studies), drug testing (21 studies), neurodegenerative diseases (40 studies), and psychiatric disorders (26 studies).

CONCLUSIONS

This review discusses several factors hindering the implementation of clinical ASL and ASL-related radiofrequency safety issues encountered in clinical practice. However, a limited number of search terms were used. Further development of robust sequences with multislice imaging capabilities and reduced radiofrequency energy deposition will hopefully improve the clinical acceptance of ASL.

PET/CT, MR, and PET/MR in Lymphoma and Melanoma

With the introduction of hybrid imaging technologies such as PET/CT and recently PET/MRI, staging and therapy-response monitoring have evolved. PET/CT has been shown to be of value for routine staging of FDG-avid lymphomas before as well as at the end of treatment. For interim staging, trials are ongoing to evaluate the use of PET/CT. In melanoma, PET/CT can be recommended for stages III and IV diseases for initial staging and before surgery. Studies investigating the use of PET/CT for early therapy response are promising. The role of PET/MR in lymphoma and melanoma imaging has to be defined because no larger studies exist so far. There may be an application of PET/MR in research especially for tumor characterization and therapy response. Furthermore, the potential role of non-FDG tracers is elucidated regarding the assessment of treatment response in targeted drug regimens.

Arterial Spin Labeling Magnetic Resonance Perfusion for Traumatic Brain Injury: Technical Challenges and Potentials

Traumatic brain injury (TBI), including concussion, is a public health concern, as it affects over 1.7 million persons in the United States per year. Yet, the diagnosis of TBI, particularly mild TBI (mTBI), can be controversial, as neuroimaging findings can be sparse on conventional magnetic resonance and computed tomography examinations, and when present, often poorly correlate with clinical signs and symptoms. Furthermore, the discussion of TBI, concussion, and head impact exposure is immediately complicated by the many differing opinions of what constitutes each, their respective severities, and how the underlying biomechanics of the inciting head impact might alter the distribution, severity, and prognosis of the underlying brain injury. Advanced imaging methodologies hold promise in improving the sensitivity and detectability of associated imaging biomarkers that might better correlate with patient outcome and prognostication, allowing for improved triage and therapeutic guidance in the setting of TBI, particularly in mTBI. This work will examine the defining symptom complex associated with mTBI and explore changes in cerebral blood flow measured by arterial spin labeling, as a potential imaging biomarker for TBI, and briefly correlate these observations with findings identified by single photon emission computed tomography and positron emission tomography imaging.

MR Imaging-Based Analysis of Glioblastoma Multiforme: Estimation of IDH1 Mutation Status

BACKGROUND AND PURPOSE

Glioblastoma multiforme is highly aggressive and the most common type of primary malignant brain tumor in adults. Imaging biomarkers may provide prognostic information for patients with this condition. Patients with glioma with isocitrate dehydrogenase 1 (IDH1) mutations have a better clinical outcome than those without such mutations. Our purpose was to investigate whether the IDH1 mutation status in glioblastoma multiforme can be predicted by using MR imaging.

MATERIALS AND METHODS

We retrospectively studied 55 patients with glioblastoma multiforme with wild type IDH1 and 11 patients with mutant IDH1. Absolute tumor blood flow and relative tumor blood flow within the enhancing portion of each tumor were measured by using arterial spin-labeling data. In addition, the maximum necrosis area, the percentage of cross-sectional necrosis area inside the enhancing lesions, and the minimum and mean apparent diffusion coefficients were obtained from contrast-enhanced T1-weighted images and diffusion-weighted imaging data. Each of the 6 parameters was compared between patients with wild type IDH1 and mutant IDH1 by using the Mann-Whitney U test. The performance in discriminating between the 2 entities was evaluated by using receiver operating characteristic analysis.

RESULTS

Absolute tumor blood flow, relative tumor blood flow, necrosis area, and percentage of cross-sectional necrosis area inside the enhancing lesion were significantly higher in patients with wild type IDH1 than in those with mutant IDH1 (P < .05 each). In contrast, no significant difference was found in the ADC(minimum) and ADC(mean). The area under the curve for absolute tumor blood flow, relative tumor blood flow, percentage of cross-sectional necrosis area inside the enhancing lesion, and necrosis area were 0.850, 0.873, 0.739, and 0.772, respectively.

CONCLUSIONS

Tumor blood flow and necrosis area calculated from MR imaging are useful for predicting the IDH1 mutation status.

A neuroradiologist's guide to arterial spin labeling MRI in clinical practice

Arterial spin labeling (ASL) is a non-invasive MRI technique to measure cerebral blood flow (CBF). This review provides a practical guide and overview of the clinical applications of ASL of the brain, as well its potential pitfalls. The technical and physiological background is also addressed. At present, main areas of interest are cerebrovascular disease, dementia and neuro-oncology. In cerebrovascular disease, ASL is of particular interest owing to its quantitative nature and its capability to determine cerebral arterial territories. In acute stroke, the source of the collateral blood supply in the penumbra may be visualised. In chronic cerebrovascular disease, the extent and severity of compromised cerebral perfusion can be visualised, which may be used to guide therapeutic or preventative intervention. ASL has potential for the detection and follow-up of arteriovenous malformations. In the workup of dementia patients, ASL is proposed as a diagnostic alternative to PET. It can easily be added to the routinely performed structural MRI examination. In patients with established Alzheimer’s disease and frontotemporal dementia, hypoperfusion patterns are seen that are similar to hypometabolism patterns seen with PET. Studies on ASL in brain tumour imaging indicate a high correlation between areas of increased CBF as measured with ASL and increased cerebral blood volume as measured with dynamic susceptibility contrast-enhanced perfusion imaging. Major advantages of ASL for brain tumour imaging are the fact that CBF measurements are not influenced by breakdown of the blood–brain barrier, as well as its quantitative nature, facilitating multicentre and longitudinal studies.

Molecular MRI differentiation between primary central nervous system lymphomas and high-grade gliomas using endogenous protein-based amide proton transfer MR imaging at 3 Tesla

OBJECTIVES

To show the ability of using the amide proton transfer-weighted (APTW) MRI signals as imaging biomarkers to differentiate primary central nervous system lymphomas (PCNSLs) from high-grade gliomas (HGGs).

METHODS

Eleven patients with lymphomas and 21 patients with HGGs were examined. Magnetization-transfer (MT) spectra over an offset range of ± 6 ppm and the conventional MT ratio (MTR) at 15.6 ppm were acquired. The APTW signals, total chemical-exchange-saturation-transfer signal (integral between 0 and 5 ppm, CEST total), and MTR signal were obtained and compared between PCNSLs and HGGs. The diagnostic performance was assessed with the receiver operating characteristic (ROC) curve analysis.

RESULTS

The PCNSLs usually showed more homogeneous APTW hyperintensity (spatially compared to normal brain tissue) than the HGGs. The APTW max, APTW max-min and CEST total signal intensities were significantly lower (P < 0.05, 0.001 and 0.05, respectively), while the APTW min and MTR were significantly higher (both P < 0.01) in PCNSL lesions than in HGG lesions. The APTW values in peritumoral oedema were significantly lower for PCNSLs than for HGGs (P < 0.01). APTW max-min had the highest area under the ROC curve (0.963) and accuracy (94.1 %) in differentiating PCNSLs from HGGs.

CONCLUSIONS

The protein-based APTW signal would be a valuable MRI biomarker by which to identify PCNSLs and HGGs presurgically.

KEY POINTS

PCNSLs overall showed more homogeneous APTW hyperintensity than HGGs. Maximum APTW signals were lower in PCNSL lesions than in HGG lesions. MTR signals were higher in PCNSLs than in HGGs. APTW heterogeneity had the highest accuracy in differentiating PCNSLs from HGGs.

Primary central nervous system lymphoma: is absence of intratumoral hemorrhage a characteristic finding on MRI?

Background.

Previous studies have shown that intratumoral hemorrhage is a common finding in glioblastoma multi-forme, but is rarely observed in primary central nervous system lymphoma. Our aim was to reevaluate whether intratumoral hemorrhage observed on T2-weighted imaging (T2WI) as gross intratumoral hemorrhage and on susceptibility-weighted imaging as intratumoral susceptibility signal can differentiate primary central nervous system lymphoma from glioblastoma multiforme.

Patients and methods.

A retrospective cohort of brain tumors from August 2008 to March 2013 was searched, and 58 patients (19 with primary central nervous system lymphoma, 39 with glioblastoma multiforme) satisfied the inclusion criteria. Absence of gross intratumoral hemorrhage was examined on T2WI, and an intratumoral susceptibility signal was graded using a 3-point scale on susceptibility-weighted imaging. Results were compared between primary central nervous system lymphoma and glioblastoma multiforme, and values of P < 0.05 were considered significant.

Results.

Gross intratumoral hemorrhage on T2WI was absent in 15 patients (79%) with primary central nervous system lymphoma and 23 patients (59%) with glioblastoma multiforme. Absence of gross intratumoral hemorrhage could not differentiate between the two disorders (P = 0.20). However, intratumoral susceptibility signal grade 1 or 2 was diagnostic of primary central nervous system lymphoma with 78.9% sensitivity and 66.7% specificity (P < 0.001), irrespective of gross intratumoral hemorrhage.

Conclusions.

Low intratumoral susceptibility signal grades can differentiate primary central nervous system lymphoma from glioblastoma multiforme. However, specificity in this study was relatively low, and primary central nervous system lymphoma cannot be excluded based solely on the presence of an intratumoral susceptibility signal.

Magnetic resonance spectroscopy detection of high lipid levels in intraaxial tumors without central necrosis: a characteristic of malignant lymphoma

OBJECT

The differentiation of malignant lymphomas from gliomas or malignant gliomas by conventional MRI can be difficult. The authors studied Gd-enhanced MR images to obtain a differential diagnosis between malignant lymphomas and gliomas without central necrosis or cystic changes and investigated the diagnostic value of single-voxel proton MR spectroscopy ((1)H-MRS) using different parameters, including lipid levels.

METHODS

This was a retrospective study of patients with primary malignant CNS lymphoma (n = 17) and glioma (n = 122 [Grades I, II, III, and IV in 10, 30, 33, and 49 patients, respectively]) who were treated between 2007 and 2013. The authors focused on 15 patients with homogeneously enhanced primary malignant CNS lymphomas and 7 homogeneously enhanced gliomas. Images of all the included tumors were acquired with (1)H-MRS at 3 T, and the diagnoses were histologically confirmed.

RESULTS

Using a short echo time (1)H-MRS, large lipid peaks were observed in all 17 patients with a malignant lymphoma, in 39 patients (79.6%) with a Grade IV glioma, and in 10 patients (30.3%) with a Grade III glioma. A focus on homogeneously enhanced tumors revealed large lipid peaks in 15 malignant lymphomas that were free of central necrosis on Gd-enhanced T1-weighted images. Conversely, in the 7 homogeneously enhanced gliomas (glioblastoma and anaplastic astrocytoma, n = 2 each; anaplastic oligodendroglioma, diffuse astrocytoma, and pilomyxoid astrocytoma, n = 1 each), lipid peaks were small or absent.

CONCLUSIONS

Large lipid peaks on (1)H-MRS images of tumors without central necrosis were characteristic of malignant lymphomas. Conversely, small or absent lipid peaks in intraaxial tumors without central necrosis were strongly suggestive of glioma.

Differentiation between primary cerebral lymphoma and glioblastoma using the apparent diffusion coefficient: comparison of three different ROI methods

Objective

Apparent diffusion coefficients (ADC) can help differentiate between central nervous system (CNS) lymphoma and Glioblastoma (GBM). However, overlap between ADCs for GBM and lymphoma have been reported because of various region of interest (ROI) methods. Our aim is to explore ROI method to provide the most reproducible results for differentiation.

Materials and Methods

We studied 25 CNS lymphomas and 62 GBMs with three ROI methods: (1) ROI₁, whole tumor volume; (2) ROI₂, multiple ROIs; and (3) ROI₃, a single ROI. Interobserver variability of two readers for each method was analyzed by intraclass correlation(ICC). ADCs were compared between GBM and lymphoma, using two-sample t-test. The discriminative ability was determined by ROC analysis.

Results

ADCs from ROI₁ showed most reproducible results (ICC >0.9). For ROI₁, ADC_mean for lymphoma showed significantly lower values than GBM (p = 0.03). The optimal cut-off value was 0.98×10⁻³ mm²/s with 85% sensitivity and 90% specificity. For ROI₂, ADC_min for lymphoma was significantly lower than GBM (p = 0.02). The cut-off value was 0.69×10⁻³ mm²/s with 87% sensitivity and 88% specificity.

Conclusion

ADC values were significantly dependent on ROI method. ADCs from the whole tumor volume had the most reproducible results. ADC_mean from the whole tumor volume may aid in differentiating between lymphoma and GBM. However, multi-modal imaging approaches are recommended than ADC alone for differentiation.

Diagnostic value of interleukin-10 in cerebrospinal fluid for diffuse large B-cell lymphoma of the central nervous system

A biomarker for early diagnosis of central nervous system (CNS) lymphoma would permit early treatment for attenuation of disease progression and neurological deterioration. High interleukin-10 (IL-10) or an IL-10/IL-6 ratio >1.0 are informative parameters for discriminating intraocular lymphomas from uveitis. Recent reports have also shown that CSF IL-10 is a potential diagnostic biomarker for CNS lymphoma. The purpose of this study was to evaluate the diagnostic value of IL-10 in cerebrospinal fluid (CSF) in patients with CNS lymphoma compared with other CNS diseases, including CNS tumors and inflammatory diseases. CSF IL-10, IL-6, beta-2 microglobulin, soluble IL-2 receptor and FDG-PET SUVmax were measured in 19 patients with CNS lymphoma (15 primary and 4 secondary diffuse large B-cell lymphomas) and 26 non-lymphoma patients with various brain tumors and inflammatory diseases. The diagnostic accuracy of the respective examinations for differentiation of CNS lymphomas from non-lymphomas was evaluated by receiver operating characteristic (ROC) curve analysis. The area under the ROC curve (AUC) was calculated. CSF IL-10 was detected at significant levels (median, 28 pg/ml; range <2-4,100 pg/ml) in all except one patient with CNS lymphoma, but not detected in any non-lymphoma patients. CSF IL-10 had the highest diagnostic accuracy with AUC = 0.974. At an IL-10 cutoff of 3 pg/ml, the sensitivity and specificity were 94.7 and 100 %, respectively. These results indicate that CSF IL-10 is a superior biomarker for initial screening for patients with CNS lymphoma.

Diffusivity of intraorbital lymphoma vs. IgG4-related DISEASE: 3D turbo field echo with diffusion-sensitised driven-equilibrium preparation technique

OBJECTIVES

3D turbo field echo with diffusion-sensitised driven-equilibrium preparation (DSDE-TFE) is a novel non-echo planar technique for diffusion-weighted (DW) imaging. The purpose of this study was to differentiate intraorbital lymphoma from immunoglobulin G4-related disease (IgG4-RD) using the apparent diffusion coefficient (ADC) derived from DSDE-TFE.

METHODS

Fifteen patients with lymphomas and 8 with IgG4-RDs underwent imaging. ADC and signal intensities compared with normal grey matter on T1-weighted images, fat-suppressed T2-weighted images and fat-suppressed postcontrast T1-weighted images were measured. Statistical analyses were performed using the Mann-Whitney U test and receiver operating characteristic (ROC) analysis.

RESULTS

Intraorbital lesions were clearly visualised on DSDE-TFE without obvious geometrical distortion. The ADC of lymphoma (1.25 ± 0.50 × 10(-3) mm(2)/s; mean ± standard deviation) was significantly lower than that of IgG4-RD (1.67 ± 0.84 × 10(-3) mm(2)/s; P < 0.05). Conventional sequences could not separate lymphoma from IgG4-RD (0.93 ± 0.18 vs. 0.94 ± 0.21 on T1-weighted images, 0.92 ± 0.17 vs. 0.95 ± 0.14 on T2-weighted images and 2.03 ± 0.35 vs. 2.30 ± 0.58 on postcontrast T1-weighted images, for lymphoma and IgG4-RD, respectively; P > 0.05). ROC analysis showed the best diagnostic performance with ADC.

CONCLUSION

The apparent diffusion coefficient derived from diffusion-sensitised driven-equilibrium preparation techniques may help to differentiate lymphoma from immunoglobulin G4-related disease.

KEY POINTS

• Distinguishing between orbital lymphoma and immunoglobulin G4-related disease can be difficult • Intraorbital lesions were clearly visualised on diffusion-sensitised driven-equilibrium preparation magnetic resonance techniques. • Variations in field homogeneity do not affect DSDE-TFE techniques all that much. • ADCs derived from DSDE-TFE may help differentiate lymphoma from IgG4-RD.

Serum miR-21 is a diagnostic and prognostic marker of primary central nervous system lymphoma

The standard of care for primary central nervous system lymphoma (PCNSL) is systemic chemotherapy with or without whole brain radiotherapy or intrathecal chemotherapy. In contrast to treatment for other brain tumors, efforts at resection are discouraged. However, it is difficult to distinguish PCNSL from other central nervous system tumors which need aggressive surgery in both CT and MRI images. In this study, we assessed whether measurement of miR-21 in the serum could improve diagnostic accuracy for PCNSL. We found that serum miR-21 significantly increased in PCNSL when compared with other brain tumors and normal controls in both test and validation cohort. Further, serum miR-21 could discriminate PCNSL from all controls with an area under the curve of 0.930 for the test cohort and 0.916 for the validation cohort in ROC analysis. Similar results were also obtained in the validation cohort. Besides, raised concentrations of miR-21 in serum could differentiate PCNSL from glioblastoma under the curve of 0.883 for the test cohort and 0.851 for the validation cohort in ROC analysis. Furthermore, Kaplan-Meier curve analysis (p = 0.03 for test cohort and 0.02 for validation cohort) and Multivariable Cox regression (p = 0.03 for test cohort and 0.01 for validation cohort) revealed serum miR-21 as an independent and powerful predictor of overall survival. Taken together, our results demonstrate that serum miR-21 may represent a diagnostic and prognostic marker for PCNSL.