Differential Diagnosis Of Brain Tumors Research Articles

An accessible deep learning tool for voxel-wise classification of brain malignancies from perfusion MRI

Noninvasive differential diagnosis of brain tumors is currently based on the assessment of magnetic resonance imaging (MRI) coupled with dynamic susceptibility contrast (DSC). However, a definitive diagnosis often requires neurosurgical interventions that compromise patients' quality of life. We apply deep learning on DSC images from histology-confirmed patients with glioblastoma, metastasis, or lymphoma. The convolutional neural network trained on ∼50,000 voxels from 40 patients provides intratumor probability maps that yield clinical-grade diagnosis. Performance is tested in 400 additional cases and an external validation cohort of 128 patients. The tool reaches a three-way accuracy of 0.78, superior to the conventional MRI metrics cerebral blood volume (0.55) and percentage of signal recovery (0.59), showing high value as a support diagnostic tool. Our open-access software, Diagnosis In Susceptibility Contrast Enhancing Regions for Neuro-oncology (DISCERN), demonstrates its potential in aiding medical decisions for brain tumor diagnosis using standard-of-care MRI.

10221-ML-11 A CASE OF PRIMARY CENTRAL NERVOUS SYSTEM ADULT T CELL LEUKEMIA

Abstract Adult T cell leukemia (ATL) manifesting only in the central nervous system (CNS) at presentation is rare. We present a case of primary CNS ATL. 54 year old male presenting with multiple enhanced lesions in the cerebrum went under biopsy and was diagnosed as T-cell lymphoma. While systemic workup was negative, human T-cell leukemia virus type 1 (HTLV-1) antibody was found to be seropositive. Southern blotting using peripheral blood DNA revealed positivity for clonal proliferation of HTLV-1 infected cells. He was therefore clinically diagnosed as primary CNS ATL. He received chemotherapy using methotrexate, procarbazine and vincristine (MPV), and gained a complete response unconfirmed (CRu) after completion of four cycles. However, relapse occurred after the fifth cycle of MPV. Salvage treatment using etoposide, cisplatin, cytarabine and prednisone (ESHAP), whole brain radiation therapy, and lenalidomide, were delivered as second, third, and fourth line therapies, but were ineffective and disease continued to progress. He was therefore treated by best supportive care. Primary CNS ATL should be considered in the differential diagnosis of brain tumors. Southern blotting using peripheral blood might be useful for clinical diagnosis in such cases.

Brain abscess nocardiosis: case report

Nocardiosis is an infection caused by Nocardia species, that are filamentous aerobic Gram-positive bacilli that belong to Actinomycetaceae family, it can cause a localized or a disseminated infection. Pulmonary disease is the most common presentation of nocardiosis in immunosuppressed patients and approximately one-third have a disseminated disease, that happens when lesions are found at two or more locations in the body. Nocardial brain abscesses are a rare central nervous system infection but has been highlighted as a differential diagnosis of brain tumors, due to the increase of the infection in deficient cell-mediated immunity patients. Even though nocardiosis represents only 2% of brain abscesses, it is an illness associated with significant mortality, present on 75% to 90% of cases. We present a case of central nervous system nocardiosis in a 59-year-old patient with a previous history of diabetes mellitus and alcoholic liver disease. The patient sought the emergency department with temporal occipital headache and mental confusion for 3 days. Imaging tests were performed that showed an oval lesion in the temporoparietooccipital region. Nocardiosis in the central nervous system was hypothesized and treatment was initiated. Despite medical support, the patient died. The lesion material was collected in which nocardiosis was diagnosed when analyzed histochemically.

Peliminary exploration on the differential diagnosis between meningioma and schwannoma using contrast-enhanced T1WI flow-sensitive black-blood sequence.

Contrast-enhanced T1WI flow-sensitive black-blood (CE-T1WI FSBB) is a newly developed sequence which had not been widely used for differential diagnosis of brain tumors. To quantify the pre-operative imaging features of intratumoral microbleeds and intratumoral vessels using CE-T1WI FSBB scan and study the differences in biological behavior of meningiomas and schwannomas underlying the imaging features. Seventy-three cases of meningiomas and 24 cases of schwannomas confirmed by postoperative pathology were included. Two neuroradiologists independently counted intratumoral vessels and intratumoral microbleeds based on CE-T1WI FSBB images. The vessel density index (VDI) and microbleed density index (MDI) were the number of intratumoral vessels and the number of intratumoral microbleeds divided by the tumor volume, respectively. The consistency test of intratumoral vessel count and intratumoral microbleed count based on CE-T1WI FSBB were summarized using 2-way random intraclass correlation coefficients (ICC). Mann-Whitney U-test and chi-square test were used to determine significant differences between meningiomas and schwannomas, and fibrous meningiomas and epithelial meningiomas. P<0.05 was considered statistically significant. The ICC of intratumoral vessels count and intratumoral microbleeds count were 0.89 and 0.99, respectively. There were significant differences in the number of intratumoral microbleeds (P<0.01) and MDI values (P<0.01) between meningiomas and schwannomas. There were no differences in the number of intratumoral vessels (P=0.64), VDI (P=0.17), or tumor volume (P=0.33). There were also differences in the number of intratumoral microbleeds (P<0.01), the MDI value (P<0.01), and the sex of patients (P<0.05) between fibrous meningiomas and epithelial meningiomas. CE-T1WI FSBB can be a new technique for differentiating schwannomas from meningiomas, and even different types of meningiomas. Schwannomas have a higher incidence of intratumoral hemorrhage, more intratumoral microbleeds, and higher MDI values than meningiomas, which provides a new basis for preoperative differential diagnosis and treatment decisions.

The role of optimal cut-off diagnosis in 11C-methionine PET for differentiation of intracranial brain tumor from non-neoplastic lesions before treatment

PurposeAmino acid positron emission tomography (PET) may provide additional information to computed tomography and magnetic resonance imaging for detecting the pretreatment diagnosis of intracranial lesions. The purpose of this study was to investigate the role of cutoff values of 11C-METPET, an amino acid PET tracer, in the differentiation of pretreatment brain tumors from non-neoplastic lesions. MethodsThis retrospective cohort study analyzed 101 pretreatment patients with a definitive diagnosis out of a total of 425 consecutive 11C-METPET imaging studies. The standardized uptake values (SUV) and the ratios of lesion to contralateral normal frontal-lobe gray matter uptake (L/N ratios) were measured. Cutoff values for the differential diagnosis of brain tumors from non-neoplastic lesions were determined using receiver operating characteristics curve (ROC) analysis. ResultsBased on the ROC analyses, the cutoffs were 3.33 for maximum SUV, 2.54 for mean SUV, 2.33 for peak SUV, 2.04 for Lmax/Nmean, and 2.23 for Lmax/Nmax. The sensitivity and specificity of these cutoffs were 69.2% and 82.6%, respectively, for maximum SUV, 64.1% and 91.3% for mean SUV, 69.2% and 91.3% for peak SUV, 70.5% and 91.3% for Lmax/Nmax and 75.6% and 82.6% for Lmax/Nmean. ConclusionIn differentiating intracranial brain tumor from non-neoplastic lesion with 11C-METPET, the use of optimal cutoff values indicates the high specificity, which means that positive result indicates the high likelihood of brain tumor. Considering the high specificity of 11C-METPET, more invasive examinations such as biopsy may be considered in positive cases.

Ensuring the most effective strategy for cancer treatment of patients with brain tumors.

e14000 Background: The purpose of the study was to analyze changes in the total activity of trypsin-like proteinases (TLPs) in the blood plasma in patients with brain tumors for the preoperative differential diagnosis of benign, primary and secondary malignant brain tumors. Methods: TLPs were measured in 164 patients with brain tumors. The blood had been collected from the patients in a standard plastic tube with 3.8% sodium citrate (9:1) 3 days prior to the surgery. Citrate blood was centrifuged; citrated plasma was obtained and used to determine the total TLP activity by the unified kinetic method. Results were compared with the data in donors. Results: TLP activity in 37 (22.6%) of 164 patients was within the normal range (258–402 IU/mL, on the average 333.0±27.1 IU/mL). Benign brain tumors (meningioma) were diagnosed in all 37 patients after the tumor removal and histological analysis. In 74 (45.1%) of 164 patients, TLP activity was within 1158–1626 IU/mL (on the average 1331.0±102.4 IU/mL, p &lt; 0.05), i.e. 3.8-5.3 times higher than the norm in donors (malignancy coefficient on average 4.4±0.3 times). Primary malignant brain tumors (glioblastoma) were diagnosed in all 74 patients after the tumor removal and histological analysis. In 53 (32.3%) of 164 patients, TLP activity was within 1794–2868 IU/mL (on the average 2227.0±174.1 IU/mL, p &lt; 0.05), i.e. 5.9-9.4 times higher than the norm in donors (malignancy coefficient on average 7.3±0.5 times). Secondary malignant brain tumors (metastases) were diagnosed in all 53 patients after the tumor removal and histological analysis. Conclusions: The specificity of the proposed method for the differential diagnosis of brain tumors was very high: for benign tumors - 97.2%, for primary malignant tumors - 98.6% and for secondary malignant tumors - 98.1%. So, TLP activity indices in the blood plasma are an informative auxiliary laboratory test that will help in clarifying and/or confirming the differential diagnosis of brain tumors.

Diagnostic Utility of the Immunohistochemical Expression of Serine and Arginine Rich Splicing Factor 1 (SRSF1) in the Differential Diagnosis of Adult Gliomas.

Simple SummaryGliomas represent a wide group of central nervous system neoplasms, arising from the glial component of the central nervous system. They are generally sub-classified into astrocytomas, oligodendrogliomas, ependymomas and other rarer subtypes. Apart from morphological and molecular features, there are currently no specific markers for this heterogeneous group of tumors: thus, there is a need to identify more specific and useful markers to distinguish each histological subtype from the others. SRSF1 has been recently characterized as being functionally involved in gliomagenesis and it has been found that SRSF1 is increased in glioma tissues and its increased immunohistochemical expression among adult diffuse astrocytomas is positively correlated with histological grade. The aim of this study is to evaluate the immunohistochemical expression of the SRSF1 protein in a series of astrocytic and non-astrocytic adult gliomas, emphasizing its potential use in the differential diagnosis of these neuropathological entities.Background: The aim of this study was to investigate the immunohistochemical expression and distribution of serine and arginine rich splicing factor 1 (SRSF1) in a series of 102 cases of both diffuse and circumscribed adult gliomas to establish the potential diagnostic role of this protein in the differential diagnosis of brain tumors. Methods: This retrospective immunohistochemical study included 42 glioblastoma cases, 21 oligodendrogliomas, 15 ependymomas, 15 pilocytic astrocytomas, 5 sub-ependymal giant cell astrocytoma and 4 pleomorphic xanthoastrocytomas. Results: Most glioblastoma (81%), oligodendroglioma (71%), sub-ependymal giant cell astrocytoma (80%) and pleomorphic xanthoastrocytoma (75%) cases showed strong SRSF1 immunoexpression, while no detectable staining was found in the majority of ependymomas (87% of cases) and pilocytic astrocytomas (67% of cases). Conclusions: The immunohistochemical expression of SRSF1 may be a promising diagnostic marker of astrocytomas and oligodendrogliomas and its increased expression might allow for excluding entities that often enter into differential diagnosis, such as ependymomas and pilocytic astrocytomas.

NIMG-01. MRI VIRTUAL BIOPSY AND TREATMENT OF PRIMARY OR BRAIN METASTATIC TUMORS WITH TARGETED NANOBIOCONJUGATES

Abstract Differential diagnosis of brain magnetic resonance imaging (MRI) enhancement(s) remains a significant problem, which may be difficult to resolve without biopsy that can be often dangerous or even impossible. Such MRI enhancement(s) can result from metastasis of primary tumors such as lung or breast, radiation necrosis, infections or a new primary brain tumor (glioma, meningioma). Neurological symptoms are often the same on initial presentation. METHODS: We present a noninvasive tumor-specific imaging approach “MRI virtual biopsy” by engineering new nano imaging agents (NIA) on polymalic acid polymer (PMLA) scaffold containing linear-Gd-DOTA or star-Gd-DOTA moieties for differential diagnosis of brain tumors. The strategy is that after non-invasive MRI diagnosis recognizing the brain lesion on the basis of its molecular signatures, the primary cancer or brain metastasis (BM) is suppressed by tumor-specific molecular inhibitor(s), which is structurally similar to the used NIA. Anti-TfR antibody or Angiopep-2 (AP-2) peptide used to cross blood-brain barrier (BBB) by receptor-mediated transcytosis, and targeting antibody against EFGR- or HER2-overexpressing tumors were covalently attached to PMLA to recognize the tissues of interest. Delivery of contrast agents across BBB was studied by optical imaging. MRI signals in healthy brain and tumors were quantified using 9.4-Tesla MRI system. RESULTS: High specific signal values prevailed for 3 hours for NIA, in comparison with clinical Gd (MultiHance) that declined rapidly. In newly developed double tumor xenogeneic mouse models of brain metastasis this method allowed differential diagnosis of HER2- and EGFR-expressing brain tumors. After MRI diagnosis, breast and lung cancer brain metastases were successfully treated with similar tumor-targeted nanoconjugates carrying molecular inhibitors of EGFR or HER2 instead of imaging contrast agent. The treatment resulted in significant increase of animal survival and markedly reduced immunostaining for several cancer stem cell markers. Support: NIH grants: R01 CA188743, R01 CA206220, R01 CA209921

Management and Diagnosis Challenges in Cystic Meningioma. A Case Report and Review of Literature

Background: Cystic meningioma is a rare variety of meningioma. It represents 4% to 7% of all meningiomas. The authors report a case of intracranial cystic meningioma with a review of literature. Case Report: A 59-year-old female presented with a history of headache followed by left side hemiplegia. CT scan and MRI of the brain showed a right parietal tumor with double solid and cystic components thought to be pilocytic astrocytoma or metastasis preoperatively. At surgery, the extraaxial solid and cystic lesion had a well defined capsule that could be easily separated from the perilesional cortical surface. The tumor was totally removed and the cyst was punctioned. The histological study showed a cystic meningioma WHO Grade I. A follow-up at 10 months after surgery, the patient was going well and recovered from the hemiplegiaa. Conclusion: Cystic meningioma is an uncommon tumor that should be considered in the differential diagnosis of brain tumors with a cystic component. The preoperative diagnosis and management could be in some cases challenging.

Update on amino acid PET of brain tumours

The aim of this study was to give an update on the emerging role of PET using radiolabelled amino acids in the diagnostic workup and management of patients with cerebral gliomas and brain metastases. Numerous studies have demonstrated the potential of PET using radiolabelled amino acids for differential diagnosis of brain tumours, delineation of tumour extent for treatment planning and biopsy guidance, differentiation between tumour progression and recurrence versus treatment-related changes, and for monitoring of therapy. The Response Assessment in Neuro-Oncology (RANO) working group - an international effort to develop new standardized response criteria for clinical trials in brain tumours - has recently recommended the use of amino acid PET imaging for brain tumour management in addition to MRI at every stage of disease. With the introduction of F-18 labelled amino acids, a broader clinical application has become possible, but is still hampered by the lack of regulatory approval and of reimbursement in many countries. PET using radiolabelled amino acids is a rapidly evolving method that can significantly enhance the diagnostic value of MRI in brain tumours. Current developments suggest that this imaging technique will become an indispensable tool in neuro-oncological centres in the near future.

OA042] Correlation of magnetic resonance spectroscopy and histological findings in brain tumors

Purpose The method of Magnetic Resonance Spectroscopy (MRS) imprints with a fast and a non-destructive manner series of brain metabolites as well as their concentration within brain parenchyma. Furthermore, it illustrates the infiltrative character of brain tumors. These MRS indicators correspond to biochemical products of the carcinogenesis procedure, such as cell proliferation, cell metabolism, cells’ destruction, necrosis, hemorrhagic and cystic elements. The combination of the macroscopic translated information of MRS along with the microscopic findings of Pathologoanatomy can differentiate in a reliable manner between the various types of cancer and assess therapies. Methods MRS technique has the potential to diagnose brain tumors in in vivo, in a non-invasive manner, without using ionizing radiation, with good spatial and temporal resolution. A number of patients with brain glioma were imaged with Magnetic Resonance Imaging (MRI). Magnetic Resonance Spectroscopy followed, as well as Perfusion measurements and post injection MRI. All examinations were performed in a 1.5 Tesla Signa HDxt General Electric system. The MRI protocol involved T2 Flair, T2, gradient-echo T2*, T1, Diffusion, Diffusion Tensor Imaging (DTI), Tractography, Perfusion and post injected contrast medium MRI. MRS protocol involved both single voxel as well as 3-D Chemical Shift Imaging (CSI). Results This study illustrates the correlation between MRI and MRS macroscopic findings with the microscopic pathologoanatomical ones: Diffusion with cellularity, DTI with neuronal axons’ destruction, Perfusion with neovascularization, MRS with brain metabolism, cell proliferation, necrosis, hemorrhage, anaerobic glycolysis, etc. MRS can also demonstrate infiltration of tumor cells within brain parenchyma even in cases where MRI fails to do so, due to the fact that the local cell biochemical background is at an initial stage. Conclusions MRS is a non-invasive technique that provides useful and conclusive information regarding differential diagnosis of brain tumors.

Potential use of prostate specific membrane antigen (PSMA) for detecting the tumor neovasculature of brain tumors by PET imaging with 89Zr-Df-IAB2M anti-PSMA minibody.

Tumor angiogenesis has attracted increasing attention because of its potential as a valuable marker in the differential diagnosis of brain tumors as well as a novel therapeutic target. Prostate-specific membrane antigen (PSMA) is expressed by the neovasculature endothelium of some tumors, with little to no expression by the tumor cells or normal vasculature endothelium. The aim of this study was to investigate the potential of PSMA for the evaluation of the tumor neovasculature of various brain tumors and the possibility of detecting PSMA expression in brain tumors using PET imaging with 89Zr-Df-IAB2M (anti-PSMA minibody). Eighty-three tissue specimens including gliomas, metastatic brain tumors, primary central nervous system lymphomas (PCNSL), or radiation necroses were analyzed by immunohistochemical staining with PSMA antibody. 89Zr-Df-IAB2M PET scans were performed in three patients with recurrent high-grade gliomas or metastatic brain tumor. PSMA was highly expressed in the vascular endothelium of high-grade glioma and metastatic brain tumor, whereas PSMA was poorly expressed in the vascular endothelium of PCNSL and radiation necrosis. PSMA expression in high-grade gliomas and a metastatic brain tumor was clearly visualized by PET imaging with 89Zr-Df-IAB2M. Furthermore, a trend toward a positive correlation between the degree of 89Zr-Df-IAB2M uptake and PSMA expression levels in tumor specimens was observed. PET imaging of PSMA using 89Zr-Df-IAB2M may have potential value in the differential diagnosis of high-grade glioma from PCNSL or radiation necrosis as well as in the prediction of treatment efficacy and assessment of treatment response to bevacizumab therapy for high-grade glioma.

Blood trypsin proteinases as a new additional test in differential diagnosis of brain tumors.

e13543 Background: Activation of trypsin-type proteinases in cancer is a proven fact. Activity of enzymes synthesized and secreted by a malignant tumor is generally not controlled by endogenous inhibitors. Benign tumors do not come into metabolic conflict with the carrier body, at least prior to their possible malignant transformation. The purpose of the study was to analyze changes in activity of trypsin proteinases (ATP) in the blood plasma of patients to determine possible application of the parameter as an additional test in the differential diagnosis of brain tumors. Methods: The blood plasma of 164 patients was studied: 37 benign brain tumors, 74 primary glioblastomas (G) and 53 brain metastases (MTS) from breast cancer. ATP was determined before treatment using the U-2900 UV Solutions double-beam spectrophotometer (USA). The results were compared to the values in 39 healthy donors (N). The data were processed using the Statistica 10 program. Results: ATP did not differ from N in 37 of 164 patients (22.6%). After removal of the brain tumors, histological examination of surgical material showed benign brain tumors in all 37 cases. ATP in 74 of 164 patients (45.1%) exceeded N by 3.8-5.3 times (on average 4.4±0.3). Histological examination after removal of the brain tumors showed primary G in all 74 cases. ATP was 5.9-9.4 times higher than N (on average 7.3±0.5) in 53 of 164 patients (32.3%). Histological examination after removal of the brain tumors showed MTS in all 53 cases. Conclusions: ATP value similar to N indicates a benign tumor. ATP increase by 3.8-5.3 times shows the presence of a primary malignant tumor. ATP increase by 5.9-9.4 times supposes MTS.

Advances in neuro-oncology imaging.

Despite the fact that MRI has evolved to become the standard method for diagnosis and monitoring of patients with brain tumours, conventional MRI sequences have two key limitations: the inability to show the full extent of the tumour and the inability to differentiate neoplastic tissue from nonspecific, treatment-related changes after surgery, radiotherapy, chemotherapy or immunotherapy. In the past decade, PET involving the use of radiolabelled amino acids has developed into an important diagnostic tool to overcome some of the shortcomings of conventional MRI. The Response Assessment in Neuro-Oncology working group - an international effort to develop new standardized response criteria for clinical trials in brain tumours - has recommended the additional use of amino acid PET imaging for brain tumour management. Concurrently, a number of advanced MRI techniques such as magnetic resonance spectroscopic imaging and perfusion weighted imaging are under clinical evaluation to target the same diagnostic problems. This Review summarizes the clinical role of amino acid PET in relation to advanced MRI techniques for differential diagnosis of brain tumours; delineation of tumour extent for treatment planning and biopsy guidance; post-treatment differentiation between tumour progression or recurrence versus treatment-related changes; and monitoring response to therapy. An outlook for future developments in PET and MRI techniques is also presented.

Diagnosis of brain tumors using dynamic contrast-enhanced perfusion imaging with a short acquisition time.

This study sought to determine the diagnostic utility of perfusion parameters derived from dynamic contrast-enhanced (DCE) perfusion MRI with a short acquisition time (approximately 3.5 min) in patients with glioma, brain metastasis, and primary CNS lymphoma (PCNSL).Twenty-six patients with 29 lesions (4 low-grade glioma, 13 high-grade glioma, 7 metastasis, and 5 PCNSL) underwent DCE-MRI in a 3 T scanner. A ROI was placed on the hotspot of each tumor in maps for volume transfer contrast Ktrans, extravascular extracellular volume Ve, and fractional plasma volume Vp. We analyzed differences in parameters between tumors using the Mann–Whitney U test. We calculated sensitivity and specificity using receiver operating characteristics analysis.Mean Ktrans values of LGG, HGG, metastasis and PCNSL were 0.034, 0.31, 0.38, 0.44, respectively. Mean Ve values of each tumors was 0.036, 0.57, 0.47, 0.96, and mean Vp value of each tumors was 0.070, 0.086, 0.26, 0.17, respectively. Compared with other tumor types, low-grade glioma showed lower Ktrans (P < 0.01, sensitivity = 88%, specificity = 100%) and lower Ve (P < 0.01, sensitivity = 96%, specificity = 100%). PCNSL showed higher Ve (P < 0.01, sensitivity = 100%, specificity = 88%), but the other perfusion parameters overlapped with those of different histology.Kinetic parameters derived from DCE-MRI with short acquisition time provide useful information for the differential diagnosis of brain tumors.

Application of31P MR Spectroscopy to the Brain Tumors

ObjectiveTo evaluate the clinical feasibility and obtain useful parameters of 31P magnetic resonance spectroscopy (MRS) study for making the differential diagnosis of brain tumors.Materials and MethodsTwenty-eight patients with brain tumorous lesions (22 cases of brain tumor and 6 cases of abscess) and 11 normal volunteers were included. The patients were classified into the astrocytoma group, lymphoma group, metastasis group and the abscess group. We obtained the intracellular pH and the metabolite ratios of phosphomonoesters/phosophodiesters (PME/PDE), PME/inorganic phosphate (Pi), PDE/Pi, PME/adenosine triphosphate (ATP), PDE/ATP, PME/phosphocreatine (PCr), PDE/PCr, PCr/ATP, PCr/Pi, and ATP/Pi, and evaluated the statistical significances.ResultsThe brain tumors had a tendency of alkalization (pH = 7.28 ± 0.27, p = 0.090), especially the pH of the lymphoma was significantly increased (pH = 7.45 ± 0.32, p = 0.013). The brain tumor group showed increased PME/PDE ratio compared with that in the normal control group (p = 0.012). The ratios of PME/PDE, PDE/Pi, PME/PCr and PDE/PCr showed statistically significant differences between each brain lesion groups (p < 0.05). The astrocytoma showed an increased PME/PDE and PME/PCr ratio. The ratios of PDE/Pi, PME/PCr, and PDE/PCr in lymphoma group were lower than those in the control group and astrocytoma group. The metastasis group showed an increased PME/PDE ratio, compared with that in the normal control group.ConclusionWe have obtained the clinically applicable 31P MRS, and the pH, PME/PDE, PDE/Pi, PME/PCr, and PDE/PCr ratios are helpful for differentiating among the different types of brain tumors.

Extramedullary Plasmacytoma Presenting as a Solitary Mass in the Intracranial Posterior Fossa

A patient with a 3-month history of headache refractory to pain medication was admitted. The CT scan and MRI showed evidence of a posterior fossa mass. This was pathologically confirmed as an extra medullary plasmacytoma (EMP). He had a pathologic fracture of the left humerus 7 years ago while the radiologist was unaware at the time of diagnosis. A solitary bone plasmacytoma (SBP) was the cause of the pathologic fracture. This report includes the first description of MRI findings in a patient with a rare-incidence intracranial solitary extra medullary plasmacytoma (SEP) in Iran. There is a striking similarity between the features of intracranial SEP and meningiomas. Intracranial SEP, although rare, should be included in the differential diagnosis of brain tumors in areas where meningiomas commonly arise. The MRI findings and differential diagnosis of plasmacytoma are reviewed. Before this case report, only few cases have been reported in the literature. Nonetheless, this is the first report of posterior fossa EMP from Iran.

Evaluation of brain tumors using dynamic 11C-methionine-PET

The aim of this study is to assess whether dynamic imaging of (11)C-methionine (MET) uptake on positron emission tomography (PET) is useful for the differential diagnosis of brain tumor histology. Regional MET uptake in static brain PET scans from three consecutive phases (5-15, 15-25, and 25-35 min) after intravenous injection were measured in 144 patients with brain tumors. Regions of interest (ROI) were placed in the pituitary gland, confluence, choroid plexus, coronal radiation, brainstem, frontal cortex, parietal cortex, cerebellum, and brain tumors. The standard uptake value (SUV) of the ROIs in the normal brain structures and brain tumors were measured, and the mean MET SUV region/normal frontal lobe cortex uptake ratio (R/N ratio) of the normal brain structures and the maximum MET SUV tumor/normal frontal cortex uptake ratio (T/N ratio) were evaluated semi-quantitatively. There were significant dynamic declines of the mean MET R/N ratio in the normal pituitary gland and confluence; however, there were significant dynamic increases in white matter. Significant dynamic decrease of the maximum MET T/N ratio was seen in meningiomas and oligodendrocytic tumors, whereas significant dynamic increase was seen in glioblastomas and malignant lymphomas. Dynamic changes of MET uptake vary significantly with the normal brain structures and brain tumor histology. These results suggest that MET-PET may be useful in the differential diagnosis of brain tumors.

Neuroimagen de los tumores cerebrales

Advances in neuroimaging have modified diagnosis, treatment and clinical management of brain tumors. However, neuropathological study remains necessary in order to get the best clinical management. Surgery and radiotherapy planning are imaging-dependent procedures, and MRI is the standard imaging modality for determining precisely tumor location and its anatomical relationship with surrounding brain structures. In high-grade tumors it has been accepted that tumoral areas with contrast uptake in CT, or T1-weighted MRI contrast enhancement corresponds to solid tumor. However, relationship between MRI and invasive tumor areas remains less defined. Therefore, it is generally accepted that conventional MRI is not sufficient to delineate the real extension of brain tumors. In recent years, PET using 18FDG and amino acid radiotracers ( 11C-Methionine, 18FDOPA, 18FET) and SPECT with 201-Thallium, as well as advanced MRI sequences (Perfusion, Diffusion-weighted, Diffusion tensor imaging and tractography), and functional MRI, have added important complementary information in the characterization, therapy planning and recurrence differential diagnosis of brain tumors. In this continuing education review of neuroimaging in brain tumors, technical aspects and clinical applications of different imaging modalities are approached in a multidisciplinary way.

Posttransplant Lymphoproliferative Disorders of the Central Nervous System After Kidney Transplantation: Single Center Experience Over 40 Years -Two Case Reports-

Posttransplant lymphoproliferative disorder (PTLD) is one of the life-threatening complications of organ transplantation. PTLD sometimes involves the central nervous system (CNS), but the clinical characteristics are not well recognized. A total of 631 patients received kidney transplantation at Osaka University Hospital between March 1965 and December 2008. Two of the 631 patients (0.32%) developed CNS PTLD. A 40-year-old Japanese woman suffered onset of CNS PTLD 5 years after renal transplantation. After diagnosis based on histological examination by open biopsy, she obtained remission with dose increase of steroid and dose reduction of mycophenolate mofetil. She experienced relapse 20 months after first remission. She underwent second biopsy and the diagnosis was recurrent CNS PTLD. Further reduction of mycophenolate mofetil and increase of steroid led to second remission. The disease remained in complete remission at 60 months after first onset. A 61-year-old woman suffered onset of CNS PTLD 19 years after renal transplantation. After tumor removal, whole brain irradiation was performed. The disease remained in remission at 54 months after onset. Histological examination showed polymorphic-type PTLD in both cases. The first case of polymorphic CNS PTLD was successfully treated by modulation of immunosuppressants without radiation therapy even at recurrence. PTLD should be included in the differential diagnosis of brain tumors in recipients of solid organ transplantation, and histological subtype should be carefully identified to establish the correct treatment strategy.