Diagnosed Brain Lesions Research Articles

Deep learning reconstruction of diffusion-weighted brain MRI for evaluation of patients with acute neurologic symptoms

Purpose: We aimed to evaluate whether the deep-learning (DL) accelerated diffusion weighted image (DWI) is clinically feasible for evaluating patients with acute neurologic symptoms, regarding its shorter study time and acceptable image quality. Materials and methods: In this retrospective study, brain images obtained at DWI with a b-value of 0 s/mm2 and DWI with a b-value of 1000 s/mm2 (DWI 1000) from 321 consecutive patients with acute stroke-like symptom were reconstructed with and without DL algorithm. We compare the diagnostic performance between DL-DWI and conventional DWI for detecting brain lesions, including acute infarction. We assessed the diagnostic accuracy of conventional DWI and DL-DWI and compared the results. Qualitative analysis based on image quality was assessed and compared using a five-point visual scoring system. Apparent diffusion coefficients (ADCs) from DWI with and without DL were also compared. Results: The mean acquisition time for the DL-DWI (49 s) was significantly shorter (P < 0.001) than conventional DWI (165 s). Both DWI with and without DL showed similar performance in diagnosing brain lesions especially sensitivity (98.8% in both DWI and DL-DWI) and specificity (99.5% in both DWI and DL-DWI). Overall image quality, gray-white matter and deep gray matter differentiation of two sequences were similar. DL DWI showed more artifacts than DWI. Lesion conspicuity, especially smaller than 5 mm, was better with DL DWI than conventional DWI (p = 0.03). ADC values of white matter, deep gray matter, and pons with DL were lower than conventional DWI. Conclusions: Compared to conventional DWI, DL-DWI achieved comparable image quality and brain lesion visualization for acute neurological symptoms, with a significantly shorter scan time.

Diagnostic Algorithm for Intracranial Lesions in the Emergency Department: Effectiveness of the Relative Brain Volume and Hounsfield Unit Value Measured by Perfusion Tomography.

Background Early treatment of intracranial lesions in the emergency department is crucial, but it can be challenging to differentiate between them. This differentiation is essential because the treatment of each type of lesion is different. Cerebral computed tomography perfusion (CTP) imaging can help visualize the vascularity of brain lesions and provide absolute quantification of physiological parameters. Compared to magnetic resonance imaging, CTP has several advantages, such as simplicity, wide availability, and reproducibility. Purpose This study aimed to assess the effectiveness of Hounsfield units (HU) in measuring the density of hypercellular lesions and the ability of CTP to quantify hemodynamics in distinguishing intracranial space-occupying lesions. Methods A retrospective study was conducted from March 2016 to March 2022. All patients underwent CTP and CT scans, and relative cerebral blood volume (rCBV) and HU were obtained for intracranial lesions. Results We included a total of 244 patients in our study. This group consisted of 87 (35.7%) individuals with glioblastomas (GBs), 48 (19.7%) with primary central nervous systemlymphoma (PCNSL), 45 (18.4%) with metastases (METs), and 64 (26.2) with abscesses. Our study showed that the HUs for METs were higher than those for GB (S 57.4% and E 88.5%). In addition, rCBV values for PCNSL and abscesses were lower than those for GB and METs. The HU in PCNSL was higher than those in abscesses (S 94.1% and E 96.6%). Conclusion PCT parameters provide valuable information for diagnosing brain lesions. A comprehensive assessment improves accuracy. Combining rCBV and HU enhances diagnostic accuracy, making it a valuable tool for distinguishing between lesions. PCT's widespread availability allows for the use of both anatomical and functional information with high spatial resolution for diagnosing and managing brain tumor patients.

Magnetic Resonance Spectroscopy of Intra-axial Gliomas With Histopathological Correlation in a Tertiary Care Center of Eastern Nepal.

Background and objective Magnetic resonance spectroscopy (MRS) is a magnetic resonance imaging technique used to identify in vivo metabolites non-invasively within the tissue of interest. It plays an important role in diagnosing brain lesions, particularly tumors and infections. There are certain metabolites whose levels are increased or decreased in brain tumors, the ratios of which can also be used to grade the tumors as high- or low-grade. This study aimed to assess the spectrum of different metabolites in intraaxial gliomas using magnetic resonance spectroscopy and to assess the usefulness of their ratios for grading gliomas into high-grade and low-grade. Methods This descriptive cross-sectional study was performed in the radiology department of Nobel Medical College and Teaching Hospital, Biratnagar, Nepal over one year (September 2019 to September 2020). Thirty-five patients diagnosed as having intra-axial tumors were enrolled. After taking informed consent the examination findings were recorded in structured proforma. Siemens' 3 Tesla open magnet MAGNETOM Skyra (Siemens Healthineers AG, Munich, Germany) MR scanner was used to evaluate each patient. Data was analyzed using the software Statistical Package for Social Sciences (SPSS), version 26.0 (IBM Corp., Armonk, NY). Results Out of 35 patients scanned, 18 had high-grade glioma and 17 had low-grade glioma. High-grade glioma had a choline/creatine (Cho/Cr) ratio of 2.44 ± 0.78 and a choline/N-acetyl-aspartate (Cho/NAA) ratio of 2.05 ± 0.84. Low-grade glioma had a Cho/Cr ratio of 1.48 ± 0.50 and a Cho/NAA ratio of 1.41 ± 0.19. Fourteen out of eighteen high-grade gliomas had raised lipid/lactate peaks. The sensitivity, specificity, positive and negative predictive values (PPV and NPV), and accuracy for diagnosing high-grade glioma with a Cho/Cr ratio cut-off of 1.5 was 83.3 %, 82.4%, 83.3%,82.4 %, and 82.85% respectively. Conclusion MRS metabolite ratios can be used to diagnose and grade gliomas. Cho/Cr, Cho/NAA, and the presence or absence of lipid/lactate peak can significantly improve the sensitivity, specificity, predictive values, and accuracy of preoperative glioma grading when used in conjunction with conventional MRI.

Epileptic versus neuro-oncological focus of management in pediatric patients with concurrent primary brain lesion and seizures: a systematic review.

Seizures can be a debilitating manifestation of underlying neoplastic intracranial pathology. Existing literature offers a paucity of scientific consensus regarding risk factors, seizure semiology, operative techniques, and tumor characteristics in pediatric patients with a concurrent diagnosis of primary intracranial neoplasm and seizures. To address the limited evidence in current literature, the authors systematically reviewed published literature on current clinical characteristics and management strategies for patients presenting concurrently with seizures and a newly diagnosed brain lesion, while aiming to synthesize a potential management protocol or set of recommendations for these patients. An initial search revealed 792 papers, of which 196 studies were excluded, leaving 596 studies available for abstract review. After further stratification, 546 studies were eliminated, leaving 50 studies for eligibility assessment. Of the 50 studies, 12 met the criteria for outcome extraction. The results indicate that patients with a mean age of 9 years with a newly diagnosed brain tumor and presenting symptoms of seizure are likely to present with daily seizures of the complex partial subtype, with the most likely primary epileptogenic and neoplastic foci occurring in the temporal lobe. The most common tumor subtypes were low-grade gliomas, ganglioglioma, dysembryoplastic neuroepithelial tumor, or astrocytoma. With the aim of gross-total resection, 77.54% of patients are likely to achieve seizure freedom. This study highlights the demographic, clinical, seizure, tumor, and postoperative outcomes for pediatric patients presenting with a primary brain tumor and concurrent seizures. Further prospective multicenter studies are necessary to understand and compare varying treatment approaches and to develop standardized guidelines for these patients, with the goal of optimizing neuro-oncological and seizure-related outcomes.

Role of Magnetic Resonance Spectroscopy in Supratentorial Brain Lesions

Aim: To identify the specificity and the sensitivity of MRS in diagnosing supratentorial brain lesions and will help the surgeons to rely on the respective diagnostic modality Method: A cross-sectional study was conducted in the Neurosurgery Department, at Jinnah Postgraduate Medical Center. The patients with conventional MR imaging showing space-occupying lesions which show a malignant diffusion restriction and enhancement were included. The histopathological diagnosis and the metabolites of the brain were detected by MR Spectroscopy were recorded. To find the association of the ratios of the brain metabolites, the chi-square test was used where a p-value of &lt;0.05 was considered significant. The sensitivity and specificity of the MRS were evaluated then. Result: Overall, 112 patients were included in our study. 76(67.9%) patients were male. Headache (34.8%) was found to be the most common symptom. 39(34.8%) patients were diagnosed with Oligodendroglioma on histopathology. The Cho/Cr ratio &gt;2 was found in 70(82.4%) patients diagnosed with neoplastic lesions. In 62(72.9%) patients diagnosed to have a neoplastic lesion on histopathology reported increased lipid peak and 67(78.8%) with the neoplastic lesion showed to have increased Cho/NAA ratio on MRS. The Cho/Cr ratio was found to be significantly associated with the neoplastic lesions with a significant p-value of &lt;0.001. The MRS was determined to be 82.4% sensitive and 70.4% specific in the diagnosis of supratentorial brain lesions. This study will be quite beneficial as it will help surgeons rely on the more accurate method of diagnosing brain lesions and provide an outlook of a non-invasive method to diagnose the lesions. Conclusion: The study concludes that MRS has high diagnostic accuracy in diagnosing neoplastic and inflammatory lesions and is Keywords: Spectroscopy, brain lesions, medical resonance imaging

When is a staging scan required for newly diagnosed brain lesions on CT? A multivariate logistic regression analysis.

For patients with a new lesion on CT head (CTH) suspected to be a brain tumor, a staging chest, abdomen, and pelvis CT (CTCAP) is only warranted if a metastatic lesion is suspected. Unnecessary CTCAPs are often performed too early in a patient's journey due to poor patient selection. We sought to create a protocol to guide the selection of patients for CTCAPs based on their CTH findings. Patients with suspected new brain tumors discussed at the neuro-oncology MDT at a tertiary neurosurgical center were reviewed. Patient demographics and CTH features were collected. For protocol creation, data was collected from July to December 2020, and predictor variables were identified using multivariate logistic regression. Candidate protocols were assessed in a protocol testing stage using similar data collected from January to June 2021. Sensitivity, specificity, and area under the curve (AUC) were computed for each protocol. Variables from the protocol creation stage (222 patients) were assessed in the protocol testing stage (216 patients). The most sensitive variables predicting metastatic disease were a previous history of cancer, multiple lesions, lesion < 4cm, and infratentorial location. A protocol recommending a CTCAP based on the presence of one of these features has a sensitivity of 99.1% (AUC 0.704). Unnecessary CTCAPs are reduced if performed only if a patient has one of the four identified predictor variables.

Newly Diagnosed Brain Tumours: When Is a Staging CT Required?

Abstract AIMS Newly diagnosed brain lesions (NBL) on imaging can be either primary or secondary in nature. Of these, only secondary brain lesions routinely require a staging CT chest, abdomen, and pelvis (CTCAP). But owing to lack of clear guidelines, all NBLs usually receive a staging investigation. This leads to over investigation of primary brain tumors. We sought to identify predictors of secondary brain lesions using CT head alone to guide the selection of patients for a CTCAP. METHOD Patients with NBLs referred to a tertiary Neurosurgical centre were reviewed. For protocol creation, data was collected from patients referred between July to December 2020, potential predictor variables were identified. Potential candidate protocols identified were assessed in a protocol-testing stage using data from a different set of patients. Sensitivity, specificity, and area under the curve (AUC) values were computed for each protocol. RESULTS The protocol-creation stage included 222 patients. Multivariate logistic regression analysis identified candidate protocols. This identified the most sensitive predictors of metastatic disease as : a previous history of cancer, multiple lesions, lesion size &amp;lt;4cm, and infratentorial location. A final protocol identified was found to have a sensitivity of 99.1% (AUC 0.704). CONCLUSION The use of the above protocol derived from this study would reduce unnecessary CTCAPs by 37.5-40% overall. Patients who do not fulfil at least one of the above said criteria on the first assessment should not have a CTCAP initially. This protocol reduces the financial and time costs from unnecessary CTCAPs as well as reduces patient exposure to radiation and contrast.

Incidence and prevalence of major epilepsy-associated brain lesions.

Epilepsy surgery is an effective treatment option for drug-resistant focal epilepsy patients with associated structural brain lesions. However, little epidemiological data are available regarding the number of patients with these lesions. We reviewed data regarding (1) the prevalence and incidence of epilepsy; (2) the proportion of epilepsy patients with focal epilepsy, drug-resistant epilepsy, and drug-resistant focal epilepsies; and (3) the number of epilepsy presurgical evaluations and surgical resections. We also assessed the relative proportion of brain lesions using post-surgical histopathological findings from 541 surgical patients from the Cleveland Clinic and 9,523 patients from a European multi-center cohort. Data were combined to generate surgical candidate incidence and prevalence estimates and the first lesion-specific estimates for hippocampal sclerosis (HS), low-grade epilepsy-associated brain tumors (LEAT), malformations of cortical development (MCD), glial scars, vascular malformations, and encephalitis. The most frequently diagnosed brain lesions were HS (incidence=2.32±0.26 in 100,000, prevalence=19.40±2.16 in 100,000) for adults and MCD (incidence=1.15±0.34 in 100,000, prevalence=6.52±1.89 in 100,000) for children. Our estimates can guide patient advocacy groups, clinicians, researchers, policymakers in education, development of health care strategy, resource allocation, and reimbursement schedules.

Diagnostic capabilities of magnetic susceptibility-weighted images in traumatic brain injury in children

Introduction. In MRI, the difference in sensitivity between tissues is used to obtain images weighted by the inhomogeneity of the magnetic field termed susceptibility-weighted imaging (SWI) and a high-resolution 3D radiofrequency gradient echo scan with full speed compensation is applied. The aim was to determine the features of lesions caused by traumatic brain injury in children using the SWI sequence. Materials and methods. 535 TBI children aged two months up to 18 years old (average age 9.58 ± 1.5) were studied. There were 325 boys (60.7%), 210 girls (39.3%). MRI was performed without and with intravenous contrast on a Phillips Achieva 3 T scanner with T1- and T2WI, 2D and 3D images, FLAIR, magnetic resonance angiography (TOF MRA), SWI, and DW/DTI, MRS and fMRI, SWI were used for visualization of DAI. Results. Patients included children with severe TBI - 178 (33.3%), moderate TBI - 172 (32.1%) and mild TBI - 185 (34.6%). Of the 535 injured children, 129 (24.1%) had MRI performed within the first 24 hours from the moment of injury, up to 48 hours - at 91 (17.0%), up to 72 hours - in 78 (14.6%) and up to 13 days - in 237 (44.3%). DAI foci at all degrees of TBI were detected in 422 (78.9%) children out of 535 children. Conclusion. SWI is a sensitive method for diagnosing brain lesions in TBI and significantly contributes to predicting outcomes in the early stages after trauma. The amount of brain lesions diagnosed by SWI correlates with the degree of injury according to the Glasgo Coma Scale. The study of the brain functional connections can inform about possible relationships between the localization of the SWI lesion and cognitive deficits, potentially providing an opportunity to use SWI in the hyperacute phase.

The Diagnostic Value of Neuron-Specific Enolase in Children with Mild Blunt Trauma Requiring Cranial CT Scan.

BackgroundThe present study was conducted to investigate the relationship between serum levels of enolase and pathological findings obtained from CT scans of the brain in children with mild blunt brain trauma and help with a more accurate diagnosis of brain injuries.MethodsThe present observational study was conducted on children presenting with head traumas to the emergency department (ED) of Golestan Hospital in Ahvaz, Iran in 2016. A venous blood sample was immediately taken by the ward nurse from all the eligible patients within 6 hrs of the incident after obtaining their information, performing initial examinations and their initial stabilization. Laboratory serum levels and the corresponding interpretations of CT scans of the brain were collected, recorded and then evaluated and analyzed.ResultsA total of 62 children with mild blunt brain trauma were included in the study. A significant difference was observed between the positive CT scan group (2.7±9.74 µg/L) and the negative group (4.23±1.33 µg/L) in terms of serum levels of enolase (P<0.0001). The area under the receiver operating characteristic (ROC) curve was 0.992 for serum levels of enolase in diagnosing brain lesions caused by mild head traumas. Moreover, with a cut-off point of 6.97 µg/L, brain lesions could be detected with a sensitivity of 93.55% and a specificity of 100%.ConclusionSerum levels of enolase were found to be higher in patients with brain injuries. This highly accurate diagnostic biomarker can be recommended for estimating the presence of brain lesions associated with mild head traumas in infants.

Intraoperative squash cytology of spinal cord lesions with histopathological correlation

Introduction: Intraoperative squash cytology of central nervous system (CNS) tumors is an extremely important modality. Diagnosing brain lesions by squash cytology has been well documented but less studies are available about its utility in spinal tumors . Objectives: Assess role of squash cytology in spinal tumors and correlate with histopathology Materials and Methods: A total of 20 cases of spinal tumor s were taken over a period of 15 months. Squash smears prepared were immediately put in 95% ethyl alcohol for 2 minutes for wet fixation and stained with rapid H and E stain and air dried smears with toluidine blue. The smears were typed according to the cytomorphological criteria and the cytodiagnoses was compared with the histopathological diagnoses and a correlation was established. Results: In our study, histopathology was taken as the gold standard. In a total of 20 cases ,the majority lesions in our series were Metastatic lesions followed by Schwannoma.The other tumors were Neuroblastoma ,ependymoma. Results were compared , there was 1 discordant lesion , and Diagnostic accuracy was 95 % .Highest diagnostic accuracy was documented in Schwannoma, Ependymoma and Neuroblastoma, PNET . Conclusion: Squash preparation is a rapid and easy method with fairly high diagnostic accuracy. If interpreted with clinical picture and radio-imaging findings, will help to reach an accurate and rapid intraoperative diagnosis in spinal lesions. Keywords: Metastatic lesions, Schwannoma, Ependymoma and Neuroblastoma.

Minimally Invasive Biopsies of Deep-Seated Brain Lesions Using Tubular Retractors Under Exoscopic Visualization

Background and Study Aims/Objective Brain lesions in deep-seated locations can present a surgical challenge. Tissue remains the gold standard for diagnosing these lesions to guide potential adjuvant therapy. These lesions have been traditionally approached by stereotactic needle biopsy, open biopsies through craniotomies, and excisional biopsies. We provide a safe alternative method using tubular retractors under exoscopic visualization for biopsies of deep-seated brain lesions. Material and Methods All patients who underwent a biopsy with the use of a tubular retractor under exoscopic visualization of a deep-seated lesion from January 2013 to September 2016 were identified prospectively and followed. This was done for patients with lesions where extensive resection was not deemed possible because of eloquent location and/or lack of impact on the natural history of the disease. Results A total of 11 patients, with an average age (plus or minus standard deviation) of 48.7 ± 18.3 years, underwent biopsies with tubular retractors and exoscopic visualization. The locations included thalamus (n = 3), optic pathway (n = 2), deep cerebellar nuclei (n = 1), centrum semiovale/corpus callosum (n = 4), and multifocal (n = 2). Diagnosis was obtained in all patients: glioblastoma multiforme (n = 3), anaplastic astrocytoma (n = 3), demyelinating disease (n = 2), renal cell cancer (n = 1), and lymphoma (n = 2). In all cases with tumors, the molecular analyses were conducted successfully. On postoperative computed tomography, no patients had notable hematomas and no patients had new deficits. Conclusion Diagnosing brain lesions is critical for guiding potential adjuvant therapies. When surgical resection is not possible or required, we report the efficacy of a tubular retractor system with exoscopic visualization for the safe access of deep-seated lesions to provide adequate tissue for diagnosis and molecular evaluation.

A Rare Case of Candida Brain Abscess Secondary to Metastatic Tongue Cancer on Initial Presentation

SESSION TITLE: Student/Resident Case Report Poster - Critical Care IV SESSION TYPE: Student/Resident Case Report Poster PRESENTED ON: Tuesday, October 25, 2016 at 01:30 PM - 02:30 PM INTRODUCTION: Fungal brain abscesses are rare causes for altered sensorium and they are often resistant to treatment, resulting in high morbidity and mortality. Brain abscesses are commonly caused due to fungal organisms, especially Candida species. CASE PRESENTATION: A 53 year old man with past medical history of diabetes presented to the emergency department after being found on the floor. The patient was alert and oriented only to place and person. Patient was diagnosed with diabetic ketoacidosis, acute kidney injury, acute pancreatitis for which he was appropriately treated. Computed tomography (CT) abdomen was consistent with left pyelonephritis and prostatic abscess. Initial urine, blood and stool cultures revealed Candida albicans. Intravenous micafungin and fluconazole were instituted based on culture reports. HIV test was negative. Magnetic resonance Imaging (MRI) of brain demonstrated ring enhancing lesions with vasogenic edema and abnormal restricted diffusion (Figure 1A & 1B). Lumbar puncture was noncontributory. Treatment was changed from micafungin to liposomal amphotericin B with fluconazole with which patient demonstrated both clinical and radiological improvement (Figure 2A &2B). Further evaluation showed an enhancing tongue mass with cervical lymphadenopathy. Biopsy proved the presence of Stage IVA squamous cell cancer of the tongue. Early neoplastic markers, Anti-Hu and Anti-Yo antibodies were negative. DISCUSSION: Candida cerebral abscess are mostly diagnosed at autopsy. An autopsy series demonstrated that up to 6% of patients with systemic candidiasis have evidence of undiagnosed CNS involvement as well. Risk factors include penetrating trauma, neurosurgical intervention, IV drug abuse, corticosteroid use, and malignancies. Candida brain abscesses can also be secondary to the infection of the adjacent structures or be secondary to hematogenous spread from endocarditis, intrabdominal or genitourinary tract infections as in our case. Risk factors present in our patient included diabetes mellitus and malignancy. Only 55% of blood cultures and 23% of lumbar puncture are positive for Candida1. CT and MRI are the preferred imaging modalities for diagnosing brain lesions and monitoring response to therapy. A definitive diagnosis can be achieved from stereotactic brain biopsy, although this is rarely reported. Infectious diseases society of America recommends liposomal Amphotericin B with flucytosine for several weeks to manage Candida brain abscess, switching to azole based therapy. CONCLUSIONS: This case demonstrates the need to consider fungal brain abscesses, as differentials for altered mental status and that with the aid of MRI and effective management, patients may improve neurologically as seen in this patient. Reference #1: Andrea M. Fennelly, Amy K. Slenker, Lara C. Murphy, Michael Moussouttas, Joseph A. Desimone. Candida cerebral abscesses: a case report and review of the literature. Med Mycol (2013) 51 (7): 779-784. DISCLOSURE: The following authors have nothing to disclose: Shyam Shankar, Sushilkumar Gupta, Ishan Malhotra, Mangalore Amith Shenoy, Hatem Desoky, Prarthna Chandar, William Pascal, Stephan Kamholz, Richard Periut, Chanaka Seneviratne, Yizhak Kupfer No Product/Research Disclosure Information

Diagnostic accuracy of F-18-fluoroethyltyrosine PET and PET/CT in patients with brain tumor

Positron emission tomography with 18F-fluoroethyltyrosine (FET-PET) is increasingly used for the initial evaluation of patients with primary brain tumors (PBTs). This article provides an up-to-date systematic review and meta-analysis of FET-PET diagnostic performances in patients with suspected PBTs. The PubMed and EMBASE databases were searched for studies published in the period January 1977–September 2012. Inclusion criteria were: (1) use of FET-PET for assessment of newly diagnosed brain lesions; (2) no radiotherapy, surgery or chemotherapy prior to FET-PET and (3) use of histology as gold standard. A per-patient meta-analysis was performed, as well as a receiver operating characteristics (ROC) analysis of pooled patients to determine optimal tumor-to-background ratio (TBR) of FET uptake. In total, 16 studies (641 patients) were included. For the diagnosis of tumoral vs non-tumoral brain lesions, FET-PET demonstrated a pooled sensitivity of 0.80 (95 % CI 0.74–0.85), specificity of 0.67 (0.44–0.84), area under the curve of 0.81 (0.78–0.85), positive likelihood ratio of 2.4 (1.3–4.7), and negative likelihood ratio of 0.29 (0.19–0.45). ROC analysis showed a meanTBR threshold ≥1.6 and a maxTBR ≥2.2 to have the best diagnostic value for differentiating PBTs from non-tumoral lesions. This meta-analysis confirms the excellent performances of FET-PET used for the diagnosis of PBTs. For FET-PET to become a relevant tool for improving patient management, prospective multicenter studies with standardized acquisition protocols should investigate its added value over current magnetic resonance imaging and the optimal combination of FET-PET and MRI.

Performance of 18F-Fluoro-Ethyl-Tyrosine (18F-FET) PET for the Differential Diagnosis of Primary Brain Tumor: A Systematic Review and Metaanalysis

For the past decade, PET with (18)F-fluoro-ethyl-tyrosine ((18)F-FET) has been used in the evaluation of patients with primary brain tumors (PBTs), but so far series have reported only a limited number of patients. The purpose of this systematic review and metaanalysis was to assess the diagnostic performance of (18)F-FET PET in patients with suspicion of PBT. We examined studies published in the literature using MEDLINE and EMBASE databases. Inclusion criteria were use of (18)F-FET PET for initial assessment of patients with a newly diagnosed brain lesion; patients who had no radiotherapy, surgery, or chemotherapy before (18)F-FET PET; and use of histology as a gold standard. Metaanalysis was performed on a per-patient basis. We secondarily performed receiver-operating-characteristic analysis of pooled patients to determine tumor-to-background ratio (TBR) of (18)F-FET uptake and best diagnostic value. Thirteen studies totaling 462 patients were included. For the diagnosis of PBT, (18)F-FET PET demonstrated a pooled sensitivity of 0.82 (95% confidence interval [CI], 0.74-0.88), specificity of 0.76 (95% CI, 0.44-0.92), area under the curve of 0.84 (95% CI, 0.80-0.87), positive likelihood ratio of 3.4 (95% CI, 1.2-9.5), and negative likelihood ratio of 0.24 (95% CI, 0.14-0.39). Receiver-operating-characteristic analysis indicated that a mean TBR threshold of at least 1.6 and a maximum TBR of at least 2.1 had the best diagnostic value for differentiating PBTs from nontumoral lesions. (18)F-FET PET demonstrated excellent performance for diagnosing PBTs. Strict standardization of PET acquisition protocols and prospective, multicenter studies investigating the added value over current MRI are now needed to establish (18)F-FET PET as a highly relevant tool for patient management.

99mTc-Tetrofosmin SPECT for the evaluation of cerebral lesions

Dear Sir, We read with great interest the recent article by Hellwig et al. investigating the utility of p-[I]iodo-L-phenylalanine (IPA) SPECT in differentiating between gliomas, metastases and gliotic or inflammatory lesions. The authors studied 67 cases of newly diagnosed brain lesions suspicious for gliomas. In visual interpretation all non-neoplastic lesions and metastases were negative; however, in the glioma group there were 11 false-negative cases, among them 3 high-grade tumours. On quantitative analysis a threshold tumour to background uptake ratio of 1.30 yielded an 88% sensitivity and 85% specificity for the differentiation between primary brain tumours and non-neoplastic lesions [1]. Our ongoing research deals with the usefulness of functional brain tumour imaging by SPECT. We are currently investigating the imaging properties of Tctetrofosmin (TF), a lipophilic diphosphine routinely used for myocardial perfusion imaging that also displays tumourseeking properties. We prospectively evaluated the role of Tc-TF in the characterization of intracranial spaceoccupying lesions. In a series of 106 patients with intracranial lesions and histological confirmation in nearly all patients, we found that Tc-TF SPECT can differentiate between lowgrade and high-grade gliomas with 91.3% sensitivity and 83.3% specificity. Besides that Tc-TF could reliably distinguish gliomas from non-neoplastic intra-axial tumours (p<0.0001). However, no significant difference between gliomas and metastases was found [2]. Previous studies demonstrated that Tc-TF uptake correlated with glioma aggressiveness, as assessed by Ki-67 immunohistochemistry and flow cytometry, and contrary to Tc-sestamibi was not influenced by the multidrug resistance profile of gliomas [3–5]. Compared to radiolabelled amino acids, Tc-TF uptake depends mainly on blood-brain barrier (BBB) disruption, regional blood flow and cell membrane integrity; thus, there is no tracer uptake in the normal brain parenchyma apart from aminor uptake in pituitary and choroid plexus, structures that lack BBB. Thus, tracer uptake can be easily identified. Furthermore, Tc-TF has the advantage of excellent availability and lower cost. To conclude, radiolabelled amino acids may hold promise for the characterization of brain space-occupying lesions. Nevertheless, Tc-TF seems to be a valuable alternative option. Future research could be focused on comparative studies not only among various radiotracers but also with the latest functional MR techniques such as perfusion imaging and spectroscopy. Funding: none G. A. Alexiou (*) : S. Voulgaris Department of Neurosurgery, University Hospital of Ioannina, P.O. Box 103, Neochoropoulo, Ioannina 455 00, Greece e-mail: alexiougrg@yahoo.gr

Prospective study of p-[123I]iodo-L-phenylalanine and SPECT for the evaluation of newly diagnosed cerebral lesions: specific confirmation of glioma

The differentiation between gliomas, metastases and gliotic or inflammatory lesions by imaging techniques remains a challenge. Gliomas frequently exhibit increased uptake of radiolabelled amino acids and are thus amenable to PET or SPECT imaging. Recently, p-[123I]iodo-L-phenylalanine (IPA) was validated for the visualization of glioma by SPECT and received orphan drug status. Here we investigated its diagnostic performance for differentiating indeterminate brain lesions. This prospective open study included 67 patients with newly diagnosed brain lesions suspicious for glioma (34 without and 33 with contrast enhancement in the MRI scan). Patients received 250 MBq IPA intravenously after overnight fasting. SPECT images at 30 min and 3 h post-injection were iteratively reconstructed and visually interpreted after image fusion with an MRI brain scan (fluid-attenuated inversion recovery sequence or T1-weighted contrast-enhanced image). Findings were correlated with results of stereotactic or open biopsies or serial imaging. Twenty-seven low-grade (2 WHO I, 25 WHO II) and 24 high-grade gliomas (1 WHO III, 23 WHO IV), 3 metastases originating from lung cancer as well as 13 non-neoplastic lesions were proven. All non-neoplastic lesions and all metastases were negative with IPA SPECT. Forty gliomas were true-positive (TP) and 11 false-negative (FN) findings (8 WHO II, 1 WHO III, 2 WHO IV) occurred. There were no false-positive (FP) findings. For the differentiation of primary brain tumours and non-neoplastic lesions, sensitivity and specificity were 78 and 100%. In 34 lesions without contrast enhancement in MRI, IPA SPECT resulted in 17 TP, 8 true-negative, 9 FN and no FP findings (sensitivity 65%, specificity 100%). In patients with suspected glioma, IPA SPECT shows a high specificity, but especially in low-grade gliomas FN findings may occur. Due to the high positive predictive value a positive finding allows a suspected glioma to be confirmed.

Clinical interest of integrating positron emission tomography imaging in the workup of 55 children with incidentally diagnosed brain lesions

In this paper, the authors' goal was to evaluate the impact of PET data on the clinical management of incidental brain lesions in children. Between 1995 and 2007, 442 children with a newly diagnosed brain lesion were referred to the authors' department. Of these, 55 presented with an incidental brain lesion and were selected for study because MR imaging sequences revealed limitations in assessing the tumor, its evolving nature, and/or the malignant potential of the lesion diagnosed. Thirteen children were studied using FDG-PET and 42 with L-(methyl-(11)C)-methionine (MET)-PET; 3 children underwent both FDG-PET and MET-PET but only the MET-PET results were used in the analysis. The PET and MR images were combined in image fusion navigation planning. Drawing on their experience with PET in adults, the authors proposed the following treatment plans: 1) surgery in children with imaging evidence of increased PET tracer uptake, which is highly specific of tumor and/or malignant tumor tissue; or 2) conservative treatment in children in whom there was little or no tracer uptake on PET. The authors compared the PET data with the MR imaging-based diagnosis and either 1) the results of histological examination in surgically treated cases, or 2) the long-term outcome in untreated cases. They studied PET and MR imaging sensitivity and specificity in detecting tumor and malignant tissues, and evaluated whether PET data altered their clinical management. Seventeen children had increased PET tracer uptake and underwent surgery. Tumor diagnosis was confirmed in all cases (that is, there were no false-positive findings). Cases in which there was little or no PET tracer uptake supported conservative treatment in 38 children. However, because PET was under evaluation, 16 of 38 lesions that were judged accessible for resection were surgically treated. Histological examination results demonstrated neither malignant nor evolving tumor tissue but yielded 9 indolent tumors (6 dysembryoplastic neuroectodermal tumors, 2 low-grade astrocytomas, and 1 low-grade astrocytoma and dysplasia) and 7 nontumoral lesions (3 cases of vasculitis, 3 of gliosis, and 1 of sarcoidosis). In 22 of the untreated 38 children, stable disease was noted during follow-up (range 18-136 months). Although an absence of PET tracer uptake might not exclude tumor tissue, PET did not reveal any false-negative findings in malignant or evolving tumor tissue detection in cases in which MR imaging showed false-positive and -negative cases in > 35 and 25% of the cases, respectively. These data confirmed the high sensitivity and specificity of PET to detect tumor as well as malignant tissue. Regarding the treatment of the incidental brain lesions, the PET findings enabled the authors to make more appropriate decisions regarding treatment than those made on MR imaging findings alone. Therefore, the risk of surgically treating a nontumoral lesion was reduced as well as that for conservatively managing a malignant tumor. Nowadays, it is estimated that these data justify conservative management in incidental lesions with low or absent PET tracer uptake.

Clinical impact of integrating positron emission tomography during surgery in 85 children with brain tumors

In this paper, the authors' goal was to evaluate the impact of PET information on brain tumor surgery in children. Between 1995 and 2007, 442 children were referred to the authors' institution for a newly diagnosed brain lesion. Of these, 85 were studied with FDG-PET and/or L-(methyl-(11)C)-methionine -PET in cases in which MR images were unable to assist in selecting accurate biopsy targets (35 patients) or to delineate tumors for maximal resection (50 patients). In surgical cases, PET and MR images were combined in image fusion planning for stereotactic biopsies or navigation-based resections. The preoperative planning images were compared postoperatively with MR imaging and PET findings and histological data for evaluating the clinical impact on the diagnostic yield and tumor resection. The PET data influenced surgical decisions or procedures in all cases. The use of PET helped to better differentiate indolent from active components in complex lesions (in 12 patients); improved target selection and diagnostic yield of stereotactic biopsies without increasing the sampling; provided additional prognostic information; reduced the amount of tissue needed for biopsy sampling in brainstem lesions (in 20 cases); better delineated lesions that were poorly delineated on MR imaging and that infiltrated functional cortex (in 50 cases); significantly increased the amount of tumor tissue removed in cases in which total resection influenced survival (in 20 cases); guided resection in hypermetabolic areas (in 15 cases); improved early postoperative detection of residual tumor (in 20 cases); avoided unnecessary reoperation (in 5 cases); and supported the decision to undertake early second-look resection (in 8 cases). The authors found that PET has a significant impact on the surgical decisions and procedures for managing pediatric brain tumors. Further studies may demonstrate whether PET improves outcomes in children.

Whole-Brain Radiation Therapy Plus Concomitant Temozolomide for the Treatment of Brain Metastases From Non–Small-Cell Lung Cancer: A Randomized, Open-Label Phase II Study

BackgroundA previously published study of temozolomide concurrent with whole-brain radiation therapy (WBRT) reported significant improvement in response rates and a nonsignificant trend toward improved overall survival compared with WBRT alone in patients with brain metastases primarily from lung cancer. This study sought to confirm the benefit of adding temozolomide to WBRT in patients with non–small-cell lung cancer (NSCLC) with brain metastases. Patients and MethodsThis planned phase III study (target = 380 events) was converted to a phase II study (target = 70 events) because of poor enrollment. Patients with NSCLC and ≥ 1 newly diagnosed brain lesion were randomized to WBRT (30 Gy in 10 fractions) alone or combined with temozolomide (75 mg/m2/day) for 21 or 28 days. Endpoints included overall survival and time to central nervous system (CNS) progression. ResultsMedian overall survival and median time to CNS progression was 4.4 and 3.1 months in the WBRT + temozolomide arm (n = 47) versus 5.7 and 3.8 months in the WBRT arm (n = 48). However, there were imbalances in the percentages of patients receiving previous chemotherapy and with synchronous brain metastases. Adding temozolomide to WBRT increased the frequency of nausea, vomiting, alopecia, fatigue, anorexia, and constipation. Most adverse events were mild to moderate. ConclusionThe benefit of adding temozolomide to WBRT was not confirmed; however, the accrual goal for the planned phase III trial was not reached, and the study regimen differed from regimens used previously. Therefore, the role of temozolomide in treating brain metastases remains unresolved.