Abnormal diffusion-weighted MRI in medulloblastoma: does it reflect small cell histology? (original) (raw)
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Journal of Neuroimaging, 2020
The molecular groups WNT activated (WNT), Sonic hedgehog activated (SHH), group 3, and group 4 are biologically and clinically distinct forms of medulloblastoma. We evaluated apparent diffusion coefficient (ADC) values' utility in differentiating/predicting medulloblastoma groups at the initial diagnostic imaging evaluation and prior to surgery. METHODS: We retrospectively measured the ADC values of the enhancing, solid portion of the tumor (EST) and of the whole tumor (WT) and performed Kruskal-Wallis testing to compare the absolute tumor ADC values and cerebellar and thalamic ratios of three medulloblastoma groups (WNT, SHH, and group 3/group 4 combined). RESULTS: Ninety-three children (65 males) were included. Fifty-seven children had group 3/group 4, 27 had SHH, and 9 had WNT medulloblastomas. The median absolute ADC values in the EST and WT were .719 × 10 −3 and .864 × 10 −3 mm 2 /s for group 3/group 4; .660 × 10 −3 and .965 × 10 −3 mm 2 /s for SHH; and .594 × 10 −3 and .728 × 10 −3 mm 2 /s for WNT medulloblastomas (P = .02 and .13). The median ratio of ADC values in the EST or the WT to normal cerebellar tissue was highest for group 3/group 4 and lowest for WNT medulloblastomas (P = .03 and .09), with similar results in pairwise comparisons of the corresponding thalamic ADC values (P = .02 and .06). CONCLUSION: ADC analysis of a tumor's contrast-enhancing solid portion may aid preoperative molecular classification/prediction of pediatric medulloblastomas and may facilitate optimal surgical treatment planning, reducing surgery-induced morbidity.
Oncotarget
Diffusion weighted imaging (DWI) has an established role in primary CNS embryonal tumor (ET) characterization; however, its diagnostic utility in detecting relapse has never been determined. We aimed to compare DWI and conventional MRI sensitivity in CNS ET recurrence detection, and to evaluate the DWI properties of contrast-enhancing radiation induced lesions (RIL). Fifty-six patients with CNS ET (25 with disease relapse, 6 with RIL and 25 with neither disease relapse nor RIL) were retrospectively evaluated with DWI, conventional MRI (including both T2/FLAIR and post-contrast images), or contrastenhanced MR imaging (CE-MRI) alone. MRI studies were independently reviewed by two neuroradiologists for detection and localization of potential brain relapses. Sensitivity for focal relapse detection was calculated for each image set on a lesionby-lesion basis. A descriptive per subject analysis was also performed. Evaluation of follow-up MRI studies served as standard of reference. Focal recurrence detection sensitivity of DWI (96%) was significantly higher than conventional MRI (77%) and CE-MRI alone (51%) (p=0.0003 and p<0.0001). On per subject analysis there were not missed diagnoses for DWI. At the time of DWI relapse detection, conventional MRI missed 2 diagnoses, and CE-MRI 8. Analysis of medulloblastoma relapses revealed that DWI identified a higher number of focal lesions than CE-MRI in subjects with classic variant. All but one RIL did not show restricted diffusion. In conclusion, DWI is a valuable complementary technique allowing for improved detection of focal relapse in CNS ET patients, particularly in children with classic medulloblastoma, and may assist in differentiating recurrence from RIL.
Surgical neurology, 2006
Background: Diffusion-weighted imaging (DWI) is an imaging modality using multi-section single-shot spin echo planar imaging (EPI) sequence which is extremely sensitive for detection of water motion within intra, extra, and transcellular regions. This character is important to differentiate between brain tumors either low (benign) or highly (malignant) cellular tumors. Objective: To evaluate the role of DWI and apparent diffusion coefficient (ADC) in evaluation and differentiation between different brain posterior fossa tumors in children and adults. Patients and methods: The study included 34 patients with different brain posterior fossa tumors for evaluation by conventional MRI (using 1.5 T MRI PHILIPS Achieva 2.1 Best Netherland) and DWI. Results: Our study showed that mean ADC values were significantly different between the four groups of posterior fossa tumors in children: juvenile pilocytic astrocytoma (JPA), medulloblastoma, ependymoma, and brain stem glioma while mean ADC values were not significantly different between posterior fossa tumors in the adult group. Regions of interest were manually positioned, and all values were automatically calculated and expressed in 10 −3 mm 2 /s. Conclusion: DWI is an ideal additional imaging technique, which is a rapid, easy, non-invasive imaging modality, with no contrast injection needed. It has been widely applied in the differentiation between posterior fossa brain tumors and in the diagnosis of various intracranial diseases.
The role of diffusion-weighted magnetic resonance imaging in pediatric brain tumors
Childs Nervous System, 2006
Objectives Diffusion-weighted imaging (DWI) may enhance the radiographic diagnosis of pediatric brain tumors. This study reviews the DWI properties of pediatric brain tumors at our institution and examines their relationship to tumor grade and type. Materials and methods The preoperative DWI and apparent diffusion coefficient (ADC) characteristics of brain tumors in 41 children were compared with histologic diagnosis. Signal characteristics on DWI and ADC maps correlated well with tumor grade. High-grade lesions were hyperintense on DWI and hypointense on ADC maps. Sensitivity, specificity, positive predictive value, and negative predictive value were 70, 100, 100, and 91%, respectively. Signal characteristics did not differ among different tumors of the same grade. All primitive neuroectodermal tumors showed diffusion restriction whereas none of the ependymomas did. Conclusions The signal characteristics on DWI and ADC maps appeared to be strongly correlated to grade in pediatric brain tumors and they may assist with preoperative diagnostic predictions.
Neurosurgery, 2006
OBJECTIVE AND IMPORTANCE: We present a rare case of very long-term medulloblastoma relapse in an adult patient and discuss the pattern of recurrence and metabolic imaging of the tumor. CLINICAL PRESENTATION: A 45-year-old man was referred for evaluation of a frontobasal midline tumor 21 years after treatment of a cerebellar medulloblastoma by surgery followed by chemotherapy and craniospinal radiotherapy. Magnetic resonance images were suggestive of a meningioma. Several hypotheses were discussed, such as other radio-induced tumors, sarcomas, high-grade gliomas, or lymphomas (previous chemotherapy) and even recurrence of medulloblastoma. Preoperative exploration included 1H magnetic resonance single-voxel spectroscopy (35 and 135 ms echo time), diffusion imaging, and perfusion magnetic resonance imaging. INTERVENTION: On magnetic resonance spectroscopy, N-acetyl-aspartate and an elevated choline/creatine ratio were retrieved, with a huge unidentified peak at 1.27 parts per million (...
Acta Radiologica, 2008
Diffusion weighted imaging (DWI) is a technique that assesses local environment at the cellular level to determine changes in the random movement of water protons. Whereas DWI is most often used to identify acute arterial ischemia, other processes that interfere with or restrict the movement of water can cause notable changes on DWI, including neoplastic lesions, encephalitis, pyogenic abscesses and occasional ABSTRACT Background: Diffusion weighted imaging (DWI) has a wide range of applications in the evaluation of intracranial pathological conditions. It provides a specific diagnosis in few situations, and adds to the information provided by conventional sequence in many others. Results: In the study group of 115 patients (41%) were females and (59%) males. Infarcts comprised 45.2% of the total cases out of these acute infarcts constituted 30 cases (57.7%); 18 (34.6%) chronic infarcts and 4 (7.6%) were subacute infarcts. All cases of acute infarcts and 50% of subacute infarcts showed diffusion restriction. None of the chronic infarcts showed true restriction of diffusion. Among intra axial tumours true restriction was noted in 6 cases. 40% of glioblastoma multiforme showed true diffusion restriction. None of the low-grade gliomas or anaplastic astrocytomas showed diffusion restriction. 75% of medulloblastomas and 50% of lymphomas showed diffusion restriction. All cases of intracerebral abscesses showed true diffusion restriction. The cystic or necrotic component of none of the brain tumours included in this study showed diffusion restriction. All cases of arachnoid cysts seen in this study had low signal on DWI. 33% of meningiomas showed restricted diffusion in this study likely reflecting their high cellularity. All cases of HII showed true diffusion restriction. 25% of these cases showed no signal change on T2WI. Also, the extent of abnormality was noted to be more on DWI than on T2WI. Two cases of extradural empyema seen in this study showed restricted diffusion similar to abscesses. Hypertensive encephalopathy and demyelination did not show restricted diffusion reflecting absence of cytotoxic oedema in these conditions. Conclusions: DW MRI helps in differentiating and characterizing intracranial lesions. Cite this article as: Chakra VV, Singh D, Makwana M, Chouhan AL, Lal K. Role of diffusion weighted magnetic resonance imaging of intra and extra axial intracranial lesions. Int Surg J 2017;4:3107-12.
Potential of Diffusion Imaging in Brain Tumors: A Review
Acta Radiologica, 2006
Diffusion magnetic resonance imaging (MRI) is a method for quantifying the microscopic random motion of water molecules in tissues. Diffusion imaging provides indirect structural information of a kind not available on basic MRI sequences of many pathological conditions. Lately, especially brain tumors have been under active investigation, with numerous papers already published, and their number continues to increase. This review summarizes the heterogeneous and complex research data on diffusion imaging of brain tumors.
Indian Journal of Radiology and Imaging, 2020
Objectives: The objective of this study is to describe the imaging features of medulloblastoma (MB) and correlate the MR characteristics with the different histological subtype of MB with 2-year survival. Materials and Methods: This is a retrospective descriptive study. A total of 29 patients diagnosed with MB from January 2005 to December 2015 were included in this study. The MRI brain and spine studies of these patients were retrieved and reviewed by a pediatric radiologist and a neuroradiologist independently, both blinded from the histological type of the MB. The HPE slides were also retrieved and reviewed by a pathologist. Results: 80% of desmoplastic MB showed the presence of intracranial leptomeningeal seeding and 57.1% of anaplastic MB showed the presence of necrosis. The presence of intracranial leptomeningeal seeding (P = 0.002) and necrosis (P = 0.019) was predictive of the histological subtypes. There is a significant correlation between the enhancement pattern and the 2-year outcome (P = 0.03) with 6 out of 8 patients whose tumors showed minimal enhancement having disease progression within 2 years. A significant correlation was also seen between the presence of necrosis with a poorer outcome (P = 0.03) and between the HPE subtype and 2-year outcome (P = 0.03) with anaplastic MB having the poorest prognosis. Conclusion: MR imaging features of intracranial leptomeningeal seeding and the presence of necrosis were correlated with a specific histologic subtype of MB. The enhancement pattern as well as necrosis correlated with 2-year poorer outcome of the disease.