Cone-Beam CT-Guided Percutaneous Transthoracic Needle Lung Biopsy of Juxtaphrenic Lesions: Diagnostic Accuracy and Complications

ObjectiveTo investigate the diagnostic accuracy and complications of cone-beam CT-guided percutaneous transthoracic needle biopsy (PTNB) of juxtaphrenic lesions and identify the risk factors for diagnostic failure and complications.Materials and MethodsIn total, 336 PTNB procedures for lung lesions (mean size ± standard deviation [SD], 4.3 ± 2.3 cm) abutting the diaphragm in 326 patients (189 male and 137 female; mean age ± SD, 65.2 ± 11.4 years) performed between January 2010 and December 2014 were included. The accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the PTNB procedures for the diagnosis of malignancy were measured based on the intention-to-diagnose principle. The risk factors for diagnostic failures and complications were evaluated using logistic regression analysis.ResultsThe accuracy, sensitivity, specificity, PPV, and NPV were 92.7% (293/316), 91.3% (219/240), 91.4% (74/81), 96.9% (219/226), and 77.9% (74/95), respectively. There were 23 diagnostic failures (7.3%), and lesion sizes ≤ 2 cm (p = 0.045) were the only significant risk factors for diagnostic failure. Complications occurred in 98 cases (29.2%), including 89 cases of pneumothorax (26.5%) and 7 cases of hemoptysis (2.1%). The multivariable analysis showed that old age (> 65 years) (p = 0.002), lesion size of ≤ 2 cm (p = 0.003), emphysema (p = 0.006), and distance from the pleura to the target lesion (> 2 cm) (p = 0.010) were significant risk factors for complications.ConclusionThe diagnostic accuracy of cone-beam CT-guided PTNB of juxtaphrenic lesions for malignancy was fairly high, and the target lesion size was the only significant predictor of diagnostic failure. Complications of cone-beam CT-guided PTNB of juxtaphrenic lesions occurred at a reasonable rate.     

CT导引四肢骨活检的价值(附50例报告)

目的　报告应用CT导引活检在四肢骨病变诊断中的方法和作用。方法　对 5 0例四肢骨病变行CT导引下活检。每例常规取样 2～ 3次。对 13例灶区或灶周硬化明显者应用了Ackmann骨钻针 ,对 42例应用了Temno核心切割针 ,12例囊性或有明显液化区的病灶则加用了细抽吸针。结果　活检的诊断准确率 88%( 4 4/5 0 )。 6例假阴性者的病灶特征包括 3例增生硬化性病灶 ,2例液化性及 1例混合性病灶。 5 0例可以分为原发恶性骨肿瘤 (n =2 3) ,原发良性骨肿瘤及肿瘤样病变 (n =12 ) ,骨转移 (n =8)及骨感染 (n =7)四类 ,其活检准确率分别为 91%、83%、10 0 %和 71%。Ackmann骨钻针、Temno核心切割针及细抽吸针的活检准确率分别为6 2 %、83%和 5 8%。未发生严重并发症。结论　CT导引下四肢骨活检是一种安全、准确而有效的方法。根据病变类型选用骨钻针、核心切割针或细抽吸针 ,并注意避开坏死区及多靶点取样 ,三种活检针的取样结果有互补性 ,合理联合使用可以提高诊断准确率。     

Ho:YAG激光在颅内肿瘤手术中的应用

为研究ＨｏＹＡＧ激光治疗颅内肿瘤的疗效，对６４例颅内肿瘤的病人开颅用ＨｏＹＡＧ激光切割治疗，手术疗效满意；尤其是脑膜瘤和颅底肿瘤疗效更佳。ＨｏＹＡＧ激光治疗颅内肿瘤较其他激光更为安全简便，是理想的方法之一。     

体部恶性肿瘤静息脑葡萄糖代谢改变与肿瘤类型的关系

目的采用18F-脱氧葡萄糖(FDG)PET/CT脑显像技术探讨无脑部疾患的体部恶性肿瘤患者的脑葡萄糖代谢异常是否与肿瘤部位有关。资料与方法 20例原发性肝癌和18例胰腺癌患者进行了全身18F-FDG PET检查,采用统计参数地形图软件(SPM)回顾性分析脑部静息葡萄糖代谢资料,并与年龄、性别相匹配的20名健康体检者进行了比较。结果原发性肝癌和胰腺癌患者均存在两侧额叶和颞叶区代谢减低,只是后者所涉及的范围和体素较前者更加广泛,尤其是前额叶皮层;胰腺癌代谢升高的区域也明显较肝癌广泛,前者主要位于两侧海马、海马旁回,杏仁核、前扣带回、后扣带回,小脑亦有广泛的葡萄糖代谢升高,而后者主要集中在扣带后回皮层区域。结论无脑部转移的体部恶性肿瘤患者存在广泛的葡萄糖代谢异常区,这些葡萄糖代息异常区的分布与肿瘤类型有关。     

Brain damage in hanging: a new CT finding

We report a 23-year-old man who attempted suicide by hanging. There have been few reports of involvement of the brain parenchyma shown on CT, all showing ischaemic lesions. This is the first report of multifocal intracerebral haematomas due to hanging seen on CT.     

Dynamic Computed Tomography Angiography in Suspected Brain Death: A Noninvasive Biomarker

Purpose

Neurologic determination of death or brain death is primarily a clinical diagnosis. This must respect all guarantees required by law and should be determined early to avoid unnecessary treatment and allow organ harvesting for transplantation. Ancillary testing is used in situations in which clinical assessment is impossible or confounded by other factors. Our purpose is to determine the utility of dynamic computed tomographic angiography (dCTA) as an ancillary test for diagnosis of brain death.

Materials and Methods

We retrospectively reviewed 13 consecutive patients with suspected brain death in the intensive care unit who had dCTA. Contrast appearance timings recorded from the dCTA data were compared to findings from 15 controls selected from patients who presented with symptoms of acute stroke but showed no stroke in follow-up imaging.

Results

The dCTA allows us to reliably assess cerebral blood flow and to record time of individual cerebral vessels opacification. It also helps us to assess the intracranial flow qualitatively against the flow in extracranial vessels as a reference. We compared the time difference between enhancement of the external and internal carotid arteries and branches. In all patients who were brain dead, internal carotid artery enhancement was delayed, which occurred after external carotid artery branches were opacified.

Conclusion

In patients with suspected brain death, dCTA reliably demonstrated the lack of cerebral blood flow, with extracranial circulation as an internal reference. Our initial results suggest that inversion of time of contrast appearance between internal carotid artery and external carotid artery branches at the skull base could predict a lack of distal intracranial flow.     

Assessment of Cerebral Circulatory Arrest via CT Angiography and CT Perfusion in Brain Death Confirmation

ObjectiveTo compare the utility of computed tomography perfusion (CTP) and three different 4-point scoring systems in computed tomography angiography (CTA) in confirming brain death (BD) in patients with and without skull defects.Materials and MethodsNinety-two patients clinically diagnosed as BD using CTA and/or CTP for confirmation were retrospectively reviewed. For the final analysis, 86 patients were included in this study. Images were re-evaluated by three radiologists according to the 4-point scoring systems that consider the vessel opacification on 1) the venous phase for both M4 segments of the middle cerebral arteries (MCAs-M4) and internal cerebral veins (ICVs) (A60-V60), 2) the arterial phase for the MCA-M4 and venous phase for the ICVs (A20-V60), 3) the venous phase for the ICVs and superior petrosal veins (ICV-SPV). The CTP images were independently reviewed. The presence of an open skull defect and stasis filling was noted.ResultsSensitivities of the ICV-SPV, A20-V60, A60-V60 scoring systems, and CTP in the diagnosis of BD were 89.5%, 82.6%, 67.4%, and 93.3%, respectively. The sensitivity of A20-V60 scoring was higher than that of A60-V60 in BD patients (p < 0.001). CTP was found to be the most sensitive method (86.5%) in patients with open skull defect (p = 0.019). Interobserver agreement was excellent in the diagnosis of BD, in assessing A20-V60, A60-V60, ICV-SPV, CTP, and good in stasis filling (κ: 0.84, 0.83, 0.83, 0.83, and 0.67, respectively).ConclusionThe sensitivity of CTA confirming brain death differs between various proposed 4-point scoring systems. Although the ICV-SPV is the most sensitive, evaluation of the SPV is challenging. Adding CTP to the routine BD CTA protocol, especially in cases with open skull defect, could increase sensitivity as a useful adjunct.     

Safety of CT-Guided Bone Marrow Biopsy in Thrombocytopenic Patients: A Retrospective Review

Purpose

To test the hypothesis that computed tomography (CT)-guided bone marrow biopsy in patients with a platelet count between 20,000/uL and 50,000/uL is safe and that preprocedure platelet transfusion is unnecessary.

CT-Guided Transthoracic Core Biopsy for Pulmonary Tuberculosis: Diagnostic Value of the Histopathological Findings in the Specimen

We evaluated the value of CT-guided transthoracic core biopsy for the diagnosis of mycobacterial pulmonary nodules. The 30 subjects in this study had pulmonary nodules that had been either diagnosed histopathologically as tuberculosis or were suspected as tuberculosis based on a specimen obtained by CT-guided transthoracic core biopsy. The histopathological findings, the existence of acid-fast bacilli in the biopsy specimens, and the clinical course of the patients after the biopsy were reviewed retrospectively. Two of the three histological findings for tuberculosis that included epithelioid cells, multinucleated giant cells and caseous necrosis were observed in 21 of the nodules which were therefore diagnosed as histological tuberculosis. Six of these 21 nodules were positive for acid-fast bacilli, confirming the diagnosis of tuberculosis. Thirteen of the 21 nodules did not contain acid-fast bacilli but decreased in size in response to antituberculous treatment and were therefore diagnosed as clinical tuberculosis. Seven nodules with only caseous necrosis were diagnosed as suspected tuberculosis, with a final diagnosis of tuberculosis being made in 4 of the nodules and a diagnosis of old tuberculosis in 2 nodules. Two nodules with only multinucleated giant cells were diagnosed as suspected tuberculosis with 1 of these nodules being diagnosed finally as tuberculosis and the other nodule as a nonspecific granuloma. When any two of the three following histopathological findings — epithelioid cells, multinucleated giant cells or caseous necrosis — are observed in a specimen obtained by CT-guided transthoracic core biopsy, the diagnosis of tuberculosis can be established without the detection of acid-fast bacilli or Mycobacterium tuberculosis.     

Hydrocephalus: Ventricular Volume Quantification Using Three-Dimensional Brain CT Data and Semiautomatic Three-Dimensional Threshold-Based Segmentation Approach

ObjectiveTo evaluate the usefulness of the ventricular volume percentage quantified using three-dimensional (3D) brain computed tomography (CT) data for interpreting serial changes in hydrocephalus.Materials and MethodsIntracranial and ventricular volumes were quantified using the semiautomatic 3D threshold-based segmentation approach for 113 brain CT examinations (age at brain CT examination ≤ 18 years) in 38 patients with hydrocephalus. Changes in ventricular volume percentage were calculated using 75 serial brain CT pairs (time interval 173.6 ± 234.9 days) and compared with the conventional assessment of changes in hydrocephalus (increased, unchanged, or decreased). A cut-off value for the diagnosis of no change in hydrocephalus was calculated using receiver operating characteristic curve analysis. The reproducibility of the volumetric measurements was assessed using the intraclass correlation coefficient on a subset of 20 brain CT examinations.ResultsMean intracranial volume, ventricular volume, and ventricular volume percentage were 1284.6 ± 297.1 cm³, 249.0 ± 150.8 cm³, and 19.9 ± 12.8%, respectively. The volumetric measurements were highly reproducible (intraclass correlation coefficient = 1.0). Serial changes (0.8 ± 0.6%) in ventricular volume percentage in the unchanged group (n = 28) were significantly smaller than those in the increased and decreased groups (6.8 ± 4.3% and 5.6 ± 4.2%, respectively; p = 0.001 and p < 0.001, respectively; n = 11 and n = 36, respectively). The ventricular volume percentage was an excellent parameter for evaluating the degree of hydrocephalus (area under the receiver operating characteristic curve = 0.975; 95% confidence interval, 0.948–1.000; p < 0.001). With a cut-off value of 2.4%, the diagnosis of unchanged hydrocephalus could be made with 83.0% sensitivity and 100.0% specificity.ConclusionThe ventricular volume percentage quantified using 3D brain CT data is useful for interpreting serial changes in hydrocephalus.     

Fluid Retention Associated with Imatinib Treatment in Patients with Gastrointestinal Stromal Tumor: Quantitative Radiologic Assessment and Implications for Management

Objective

We aimed to describe radiologic signs and time-course of imatinib-associated fluid retention (FR) in patients with gastrointestinal stromal tumor (GIST), and its implications for management.

Materials and Methods

In this Institutional Review Board-approved, retrospective study of 403 patients with GIST treated with imatinib, 15 patients with imaging findings of FR were identified by screening radiology reports, followed by manual confirmation. Subcutaneous edema, ascites, pleural effusion, and pericardial effusion were graded on a four-point scale on CT scans; total score was the sum of these four scores.

Results

The most common radiologic sign of FR was subcutaneous edema (15/15, 100%), followed by ascites (12/15, 80%), pleural effusion (11/15, 73%), and pericardial effusion (6/15, 40%) at the time of maximum FR. Two distinct types of FR were observed: 1) acute/progressive FR, characterized by acute aggravation of FR and rapid improvement after management, 2) intermittent/steady FR, characterized by occasional or persistent mild FR. Acute/progressive FR always occurred early after drug initiation/dose escalation (median 1.9 month, range 0.3-4.0 months), while intermittent/steady FR occurred at any time. Compared to intermittent/steady FR, acute/progressive FR was severe (median score, 5 vs. 2.5, p = 0.002), and often required drug-cessation/dose-reduction.

Conclusion

Two distinct types (acute/progressive and intermittent/steady FR) of imatinib-associated FR are observed and each type requires different management.     

CT引导下经皮肺穿刺活检:18G和20G穿刺针的比较

目的探讨应用18G、20G自动切割针行CT引导下经皮肺穿刺活检的诊断效率和并发症的差异。方法对比分析应用18G和20G自动切割针肺活检的2组各60例的诊断效率和并发症。结果18G组肺癌48例,穿刺确诊45例,确诊率93.8%,假阴性3例,假阴性率6.2%;良性病变12例,其中10例穿刺活检确诊。20G组肺癌46例,穿刺确诊42例,确诊率91.3%,假阴性4例,假阴性率8.7%;14例良性病变,其中10例穿刺活检确诊。18G组有20例发生气胸,2例需闭式引流处理,20G组有8例发生气胸,均是少量气胸,无需特殊处理。2组在确诊率、假阴性率、气胸发生率进行统计学处理,经χ2检验,P值>0.05,两者均无显著性差异。结论18G、20G2组在确诊率、假阴性率、气胸发生率均无显著差异,但18G组的气胸发生率及严重程度均高于20G组。     

Recent Advances and Future Directions in Brain MR Imaging Studies in Schizophrenia: Toward Elucidating Brain Pathology and Developing Clinical Tools

Schizophrenia is a common severe psychiatric disorder that affects approximately 1% of general population through the life course. Historically, in Kraepelin’s time, schizophrenia was a disease unit conceptualized as dementia praecox; however, since then, the disease concept has changed. Recent MRI studies had shown that the neuropathology of the brain in this disorder was characterized by mild progression before and after the onset of the disease, and that the brain alterations were relatively smaller than assumed. Although genetic factors contribute to the brain alterations in schizophrenia, which are thought to be trait differences, other changes include factors that are common in psychiatric diseases. Furthermore, it has been shown that the brain differences specific to schizophrenia were relatively small compared to other changes, such as those caused by brain development, aging, and gender. In addition, compared to the disease and participant factors, machine and imaging protocol differences could affect MRI signals, which should be addressed in multi-site studies. Recent advances in MRI modalities, such as multi-shell diffusion-weighted imaging, magnetic resonance spectroscopy, and multimodal brain imaging analysis, may be candidates to sharpen the characterization of schizophrenia-specific factors and provide new insights. The Brain/MINDS Beyond Human Brain MRI (BMB-HBM) project has been launched considering the differences and noises irrespective of the disease pathologies and includes the future perspectives of MRI studies for various psychiatric and neurological disorders. The sites use restricted MRI machines and harmonized multi-modal protocols, standardized image preprocessing, and traveling subject harmonization. Data sharing to the public will be planned in FY 2024. In the future, we believe that combining a high-quality human MRI dataset with genetic data, randomized controlled trials, and MRI for non-human primates and animal models will enable us to understand schizophrenia, elucidate its neural bases and therapeutic targets, and provide tools for clinical application at bedside.     

Needle tract implantation after percutaneous interventional procedures in hepatocellular carcinomas: lessons learned from a 10-year experience.

Percutaneous interventional procedures under image guidance, such as biopsy, ethanol injection therapy, and radiofrequency ablation play important roles in the management of hepatocellular carcinomas. Although uncommon, the procedures may result in tumor implantation along the needle tract, which is a major delayed complication. Implanted tumors usually appear as one or a few, round or oval-shaped, enhancing nodules along the needle tract on CT, from the intraperitoneum through the intercostal or abdominal muscles to the subcutaneous or cutaneous tissues. Radiologists should understand the mechanisms and risk factors of needle tract implantation, minimize this complication, and also pay attention to the presence of implanted tumors along the needle tract during follow-up.     

Multiphasic Perfusion CT in Acute Middle Cerebral Artery Ischemic Stroke: Prediction of Final Infarct Volume and Correlation with Clinical Outcome

Objective

To assess the utility of multiphasic perfusion CT in the prediction of final infarct volume, and the relationship between lesion volume revealed by CT imaging and clinical outcome in acute ischemic stroke patients who have not undergone thrombolytic therapy.

Materials and Methods

Thirty-five patients underwent multiphasic perfusion CT within six hours of stroke onset. After baseline unenhanced helical CT scanning, contrast-enhanced CT scans were obtained 20, 34, 48, and 62 secs after the injection of 90 mL contrast medium at a rate of 3 mL/sec. CT peak and total perfusion maps were obtained from serial CT images, and the initial lesion volumes revealed by CT were compared with final infarct volumes and clinical scores.

Results

Overall, the lesion volumes seen on CT peak perfusion maps correlated most strongly with final infarct volumes (R²=0.819, p<0.001, slope of regression line=1.016), but individual data showed that they were less than final infarct volume in 31.4% of patients. In those who showed early clinical improvement (n=6), final infarct volume tended to be overestimated by CT peak perfusion mapping and only on total perfusion maps was there significant correlation between lesion volume and final infarct volume (R²=0.854, p=0.008). The lesion volumes depicted by CT maps showed moderate correlation with baseline clinical scores and clinical outcomes (R=0.445-0.706, p≤0.007).

Conclusion

CT peak perfusion maps demonstrate strong correlation between lesion volume and final infarct volume, and accurately predict final infarct volume in about two-thirds of the 35 patients. The lesion volume seen on CT maps shows moderate correlation with clinical outcome.     

Intravascular Ultrasound-Guided Transvenous Biopsy of Retroperitoneal Lymph Nodes: Diagnostic Accuracy and Safety Compared with CT-Guided Percutaneous Biopsy

PurposeTo compare the diagnostic accuracy and adverse event rates of intravascular ultrasound (US)-guided transvenous biopsy (TVB) versus those of computed tomography (CT)-guided percutaneous needle biopsy (PNB) for retroperitoneal (RP) lymph nodes.Materials and MethodsIn this single-institution, retrospective study, 32 intravascular US-guided TVB procedures and a sample of 34 CT-guided PNB procedures for RP lymph nodes where targets were deemed amenable to intravascular US-guided TVB were analyzed. Procedural metrics, including diagnostic accuracy, defined as diagnostic of malignancy or a clinically verifiable benign result, and adverse event rates were compared.ResultsThe targets of intravascular US-guided TVB were primarily aortocaval (47%, 15/32) or precaval (34%, 11/32), whereas those of CT-guided PNB were primarily right pericaval (44%, 15/34) or retrocaval (44%, 15/34) (P < .001). The targets of intravascular US-guided TVB averaged 2.4 cm in the long axis (range, 1.3–3.7 cm) compared with 2.9 cm (range, 1.4–5.7 cm) for those of CT-guided PNB (P = .02). There was no difference in the average number of needle passes (3.8 for intravascular US-guided TVB vs 3.9 for CT-guided PNB; P = .68). The diagnostic accuracy was 94% (30/32) and the adverse event rate was 3.1% (1/32) for intravascular US-guided TVB, similar to those of CT-guided PNB (accuracy, 91% [31/34]; adverse event rate, 2.9% [1/34]).ConclusionsIntravascular US-guided TVB had a diagnostic accuracy and adverse event rate similar to CT-guided PNB for RP lymph nodes, indicating that intravascular US-guided TVB may be as safe and effective as conventional biopsy approaches for appropriately selected targets.     

Neuroimaging Findings in Patients with COVID-19: A Systematic Review and Meta-Analysis

ObjectiveCentral nervous system involvement in coronavirus disease 2019 (COVID-19) has been increasingly reported. We performed a systematic review and meta-analysis to evaluate the incidence of radiologically demonstrated neurologic complications and detailed neuroimaging findings associated with COVID-19.Materials and MethodsA systematic literature search of MEDLINE/PubMed and EMBASE databases was performed up to September 17, 2020, and studies evaluating neuroimaging findings of COVID-19 using brain CT or MRI were included. Several cohort-based outcomes, including the proportion of patients with abnormal neuroimaging findings related to COVID-19 were evaluated. The proportion of patients showing specific neuroimaging findings was also assessed. Subgroup analyses were also conducted focusing on critically ill COVID-19 patients and results from studies that used MRI as the only imaging modality.ResultsA total of 1394 COVID-19 patients who underwent neuroimaging from 17 studies were included; among them, 3.4% of the patients demonstrated COVID-19-related neuroimaging findings. Olfactory bulb abnormalities were the most commonly observed (23.1%). The predominant cerebral neuroimaging finding was white matter abnormality (17.6%), followed by acute/subacute ischemic infarction (16.0%), and encephalopathy (13.0%). Significantly more critically ill patients had COVID-19-related neuroimaging findings than other patients (9.1% vs. 1.6%; p = 0.029). The type of imaging modality used did not significantly affect the proportion of COVID-19-related neuroimaging findings.ConclusionAbnormal neuroimaging findings were occasionally observed in COVID-19 patients. Olfactory bulb abnormalities were the most commonly observed finding. Critically ill patients showed abnormal neuroimaging findings more frequently than the other patient groups. White matter abnormalities, ischemic infarctions, and encephalopathies were the common cerebral neuroimaging findings.     

Renal cell carcinoma in uremic acquired renal cystic disease: Incidence,detection, and management

We describe three patients with puzzling systemic illnesses in whom computed tomography (CT) led to the diagnosis of active adrenal histoplasmosis. CT was performed in two patients because of gastrointestinal symptoms and weight loss and in the third because of fever developing 2 years after an apparent cure of histoplasmosis. All three patients had adrenal enlargement on CT with features of granulomatous adrenal disease in two. Hormone assays performed after CT supported the diagnosis of adrenal insufficiency and fine-needle adrenal aspiration biopsy with special stains of the aspirates showed histoplasma organisms in all three patients. The combination of adrenal enlargement on CT and laboratory findings of adrenal insufficiency should suggest the diagnosis of histoplasmosis, especially in endemic areas.     

Effective Dose of CT- and Fluoroscopy-Guided Perineural/Epidural Injections of the Lumbar Spine: A Comparative Study

The objective of this study was to compare the effective radiation dose of perineural and epidural injections of the lumbar spine under computed tomography (CT) or fluoroscopic guidance with respect to dose-reduced protocols. We assessed the radiation dose with an Alderson Rando phantom at the lumbar segment L4/5 using 29 thermoluminescence dosimeters. Based on our clinical experience, 4–10 CT scans and 1-min fluoroscopy are appropriate. Effective doses were calculated for CT for a routine lumbar spine protocol and for maximum dose reduction; as well as for fluoroscopy in a continuous and a pulsed mode (3–15 pulses/s). Effective doses under CT guidance were 1.51 mSv for 4 scans and 3.53 mSv for 10 scans using a standard protocol and 0.22 mSv and 0.43 mSv for the low-dose protocol. In continuous mode, the effective doses ranged from 0.43 to 1.25 mSv for 1–3 min of fluoroscopy. Using 1 min of pulsed fluoroscopy, the effective dose was less than 0.1 mSv for 3 pulses/s. A consequent low-dose CT protocol reduces the effective dose compared to a standard lumbar spine protocol by more than 85%. The latter dose might be expected when applying about 1 min of continuous fluoroscopy for guidance. A pulsed mode further reduces the effective dose of fluoroscopy by 80–90%.     

Medulloblastoma in children: CT and MRI findings

Our purpose was to determine whether medulloblastoma (MB) shows specific neuroradiological features which may be employed in differential diagnosis from other common posterior cranial fossa tumours in childhood. Preoperative MRI was performed on 20 children with MB, and preoperative CT in 17 of them. All underwent surgery and histopathological diagnosis. There was a constant relationship between high density on CT and low signal on T1-weighted images. Signal behaviour on T2-weighted images and the degree of contrast enhancement were more variable. Most tumours arose in the midline, from the cerebellar vermis, involving the fourth ventricle, but hemisphere and extra-axial neoplasms were also seen. The combination of high density on CT and low signal on T1-weighted images is highly suggestive of MB and may assist preoperative differential diagnosis from other posterior cranial fossa tumours.