Accuracy and reproducibility of automated white matter hyperintensities segmentation with lesion segmentation tool: A European multi-site 3T study

Brain vascular damage accumulate in aging and often manifest as white matter hyperintensities (WMHs) on MRI. Despite increased interest in automated methods to segment WMHs, a gold standard has not been achieved and their longitudinal reproducibility has been poorly investigated. The aim of present work is to evaluate accuracy and reproducibility of two freely available segmentation algorithms. A harmonized MRI protocol was implemented in 3T-scanners across 13 European sites, each scanning five volunteers twice (test-retest) using 2D-FLAIR. Automated segmentation was performed using Lesion segmentation tool algorithms (LST): the Lesion growth algorithm (LGA) in SPM8 and 12 and the Lesion prediction algorithm (LPA). To assess reproducibility, we applied the LST longitudinal pipeline to the LGA and LPA outputs for both the test and retest scans. We evaluated volumetric and spatial accuracy comparing LGA and LPA with manual tracing, and for reproducibility the test versus retest. Median volume difference between automated WMH and manual segmentations (mL) was -0.22[IQR = 0.50] for LGA-SPM8, -0.12[0.57] for LGA-SPM12, -0.09[0.53] for LPA, while the spatial accuracy (Dice Coefficient) was 0.29[0.31], 0.33[0.26] and 0.41[0.23], respectively. The reproducibility analysis showed a median reproducibility error of 20%[IQR = 41] for LGA-SPM8, 14% [31] for LGA-SPM12 and 10% [27] with the LPA cross-sectional pipeline. Applying the LST longitudinal pipeline, the reproducibility errors were considerably reduced (LGA: 0%[IQR = 0], p < 0.001; LPA: 0% [3], p < 0.001) compared to those derived using the cross-sectional algorithms. The DC using the longitudinal pipeline was excellent (median = 1) for LGA [IQR = 0] and LPA [0.02]. LST algorithms showed moderate accuracy and good reproducibility. Therefore, it can be used as a reliable cross-sectional and longitudinal tool in multi-site studies.

Amygdalar nuclei and hippocampal subfields on MRI: Test-retest reliability of automated volumetry across different MRI sites and vendors

BACKGROUND

The amygdala and the hippocampus are two limbic structures that play a critical role in cognition and behavior, however their manual segmentation and that of their smaller nuclei/subfields in multicenter datasets is time consuming and difficult due to the low contrast of standard MRI. Here, we assessed the reliability of the automated segmentation of amygdalar nuclei and hippocampal subfields across sites and vendors using FreeSurfer in two independent cohorts of older and younger healthy adults.

METHODS

Sixty-five healthy older (cohort 1) and 68 younger subjects (cohort 2), from the PharmaCog and CoRR consortia, underwent repeated 3D-T1 MRI (interval 1-90 days). Segmentation was performed using FreeSurfer v6.0. Reliability was assessed using volume reproducibility error (ε) and spatial overlapping coefficient (DICE) between test and retest session.

RESULTS

Significant MRI site and vendor effects (p ​< ​.05) were found in a few subfields/nuclei for the ε, while extensive effects were found for the DICE score of most subfields/nuclei. Reliability was strongly influenced by volume, as ε correlated negatively and DICE correlated positively with volume size of structures (absolute value of Spearman's r correlations >0.43, p ​< ​1.39E-36). In particular, volumes larger than 200 ​mm³ (for amygdalar nuclei) and 300 ​mm³ (for hippocampal subfields, except for molecular layer) had the best test-retest reproducibility (ε ​< ​5% and DICE ​> ​0.80).

CONCLUSION

Our results support the use of volumetric measures of larger amygdalar nuclei and hippocampal subfields in multisite MRI studies. These measures could be useful for disease tracking and assessment of efficacy in drug trials.

Comparison between conventional MRI and MR arthrography in the diagnosis of triangular fibrocartilage tears and correlation with arthroscopic findings

PURPOSE

The triangular fibrocartilage complex is one of the most important stabilizers of the wrist and a defect in its anatomical structure is a possible cause of ulnar sided wrist pain. The aim of this study is to compare the diagnostic accuracy between conventional MRI and MR arthrography (MRA) in the depiction of triangular fibrocartilage complex (TFCC) tears.

METHODS-MATERIALS

A total of 60 patients with clinical findings that suggested TFCC tears underwent wrist MRI and MRA. All the MRI and MRA results were compared with the arthroscopic findings.

RESULTS

40 tears were confirmed by arthroscopy. 38/40 tears were identified by MRA while MRI identified 26/40 tears. There were also 8 false positives and 13 false negative results identified by MRI. Two false negative results were identified by MRA. No false positive results were identified.

CONCLUSION

MR arthrography is more sensitive and specific method in terms of the diagnosis of TFCC tears compared to conventional wrist MRI. There was no difference in the diagnostic accuracy between wrist arthroscopy and MRA.

Extending 2-D Convolutional Neural Networks to 3-D for Advancing Deep Learning Cancer Classification With Application to MRI Liver Tumor Differentiation

Deep learning (DL) architectures have opened new horizons in medical image analysis attaining unprecedented performance in tasks such as tissue classification and segmentation as well as prediction of several clinical outcomes. In this paper, we propose and evaluate a novel three-dimensional (3-D) convolutional neural network (CNN) designed for tissue classification in medical imaging and applied for discriminating between primary and metastatic liver tumors from diffusion weighted MRI (DW-MRI) data. The proposed network consists of four consecutive strided 3-D convolutional layers with 3 × 3 × 3 kernel size and rectified linear unit (ReLU) as activation function, followed by a fully connected layer with 2048 neurons and a Softmax layer for binary classification. A dataset comprising 130 DW-MRI scans was used for the training and validation of the network. To the best of our knowledge this is the first DL solution for the specific clinical problem and the first 3-D CNN for cancer classification operating directly on whole 3-D tomographic data without the need of any preprocessing step such as region cropping, annotating, or detecting regions of interest. The classification performance results, 83% (3-D) versus 69.6% and 65.2% (2-D), demonstrated significant tissue classification accuracy improvement compared to two 2-D CNNs of different architectures also designed for the specific clinical problem with the same dataset. These results suggest that the proposed 3-D CNN architecture can bring significant benefit in DW-MRI liver discrimination and potentially, in numerous other tissue classification problems based on tomographic data, especially in size-limited, disease-specific clinical datasets.

Free water elimination improves test-retest reproducibility of diffusion tensor imaging indices in the brain: A longitudinal multisite study of healthy elderly subjects

Free water elimination (FWE) in brain diffusion MRI has been shown to improve tissue specificity in human white matter characterization both in health and in disease. Relative to the classical diffusion tensor imaging (DTI) model, FWE is also expected to increase sensitivity to microstructural changes in longitudinal studies. However, it is not clear if these two models differ in their test-retest reproducibility. This study compares a bi-tensor model for FWE with DTI by extending a previous longitudinal-reproducibility 3T multisite study (10 sites, 7 different scanner models) of 50 healthy elderly participants (55-80 years old) scanned in two sessions at least 1 week apart. We computed the reproducibility of commonly used DTI metrics (FA: fractional anisotropy, MD: mean diffusivity, RD: radial diffusivity, and AXD: axial diffusivity), derived either using a DTI model or a FWE model. The DTI metrics were evaluated over 48 white-matter regions of the JHU-ICBM-DTI-81 white-matter labels atlas, and reproducibility errors were assessed. We found that relative to the DTI model, FWE significantly reduced reproducibility errors in most areas tested. In particular, for the FA and MD metrics, there was an average reduction of approximately 1% in the reproducibility error. The reproducibility scores did not significantly differ across sites. This study shows that FWE improves sensitivity and is thus promising for clinical applications, with the potential to identify more subtle changes. The increased reproducibility allows for smaller sample size or shorter trials in studies evaluating biomarkers of disease progression or treatment effects. Hum Brain Mapp 38:12-26, 2017. © 2016 Wiley Periodicals, Inc.

Diffusion weighted MRI and spectroscopy in invasive carcinoma of the breast at 3Tesla. Correlation with dynamic contrast enhancement and pathologic findings

BACKGROUND

The most common histological types of invasive breast carcinomas are the invasive ductal carcinoma (IDC) and the invasive lobular carcinoma (ILC). The purpose of our study was to evaluate the role of the diffusion-weighted imaging (DWI) and the in vivo proton magnetic resonance spectroscopy (¹H-MRS ) at 3 Tesla magnet in invasive breast cancer and correlate them with the dynamic contrast enhancement (DCE) and pathologic findings.

METHODS

We retrospectively studied at 3Tesla magnet the apparent diffusion coefficient (ADC) values, the detection of choline in the ¹H-MRS and the kinetic analyses obtained after DCE in 181 patients with histologically confirmed invasive breast carcinomas. Among these patients, 160 had IDC and 21 ILC. We used the DWI sequence with a b value of 1,000 mm²/sec for the calculation of the ADC value, the fat-suppressed point-resolved spectroscopy (PRESS) sequence in order to evaluate the existence of a choline peak in the spectrum and the T₁W GRE FAT SAT VIBRANT sequence for the characterization of the kinetic curves. Finally, we correlated the pathologic type of invasive cancer, as well as the type of the kinetic curve with the ADC value and the detectability of choline resonance in the spectrum in each of the 181 patients.

RESULTS

The ADC values in the 158 out of 160 IDC patients, ranged from 0.5 x 10^-3 to 1.2 x 10^-3 mm²/sec, with 78.1 % having ADC value of 1 x 10^-3 mm²/sec. Regarding the ¹H-MRS, in 121 out of 160 IDC patients, choline was found in 72.3 %. The ADC values in the 21 ILC patients also ranged from 0.5 x 10^-3 to 1.2 x 10^-3 mm²/sec with 57.1 % having ADC value of 1 x 10^-3 mm²/sec. Regarding the ¹H-MRS, in 10 out of 21 ILC patients, detection of choline was positive in 60 % of them. In the 21 ILC patients, the kinetic analysis after the dynamic administration of contrast medium showed type I (persistent) curve in 4.3 %, type II (plateau) curve in 33.3 % and type III (washout) in 52.4 %. In the 158 IDC patients (missing in two cases) type I curve was obtained in 0.63 %, type II in 19.4 % and type III in 80 %. From the correlation analysis of the IDC results using Kruskal-Wallis Test and the non-parametric Kendall's tau-b test, the curve type was positively associated (Kendal tau-b: 0.254, p =0.005) with the presence of choline, while the ADC value was negatively associated (Kendal tau-b: -0.224, p =0.011) with the presence of choline. In the ILC cases, the sample was insufficient for the correlation to become statistically significant. However, the ADC values tended to be lower in IDC patients (78.1 % having ADC value 1 x 10^-3 mm²/sec) compared to ILC (57.1 % having ADC value 1 x 10^-3 mm²/sec). Choline was more commonly detected in the IDC (72.3 %) than ILC (60 %) patients.

CONCLUSION

Our results are consistent with previous findings that both ADC values and choline detection in the spectrum play a significant role in establishing the final diagnosis of malignancy, especially when the kinetic pattern of enhancement is misleading. Hippokratia 2016, 20(3): 192-197.

Apparent Diffusion Coefficient Quantification in Determining the Histological Diagnosis of Malignant Liver Lesions

Purpose: Diffusion Weighted Imaging is an established diagnostic tool for accurate differential diagnosis between benign and malignant liver lesions. The aim of our study was to evaluate the role of Histogram Analysis of ADC quantification in determining the histological diagnosis as well as the grade of malignant liver tumours. To our knowledge, there is no study evaluating the role of Histogram Analysis of ADC quantification in determining the histological diagnosis as well as the grade of malignant liver tumours.

Methods: During five years, 115 patients with known liver lesions underwent Diffusion Weighted Imaging in 3Tesla MR scanner prior to core needle biopsy. Histogram analyses of ADC in regions of interest were drawn and were correlated with biopsy histological diagnosis and grading.

Results: Histogram analysis of ADC values shows that 5th and 30th percentile parameters have statistically significant potency of discrimination between primary and secondary lesions groups (p values 0.0036 and 0.0125 respectively). Skewness of the histogram can help discriminate between good and poor differentiated (p value 0.17). Discrimination between primary malignancy site in metastases failed for the present number of patients in each subgroup.

Conclusion: Statistical parameters reflecting the shape of the left side of the ADC histogram can be useful for discriminating between primary and secondary lesions and also between well differentiated versus moderate or poor. For the secondary malignancies, they failed to predict the original site of tumour.

Test-retest reliability of the default mode network in a multi-centric fMRI study of healthy elderly: Effects of data-driven physiological noise correction techniques

Understanding how to reduce the influence of physiological noise in resting state fMRI data is important for the interpretation of functional brain connectivity. Limited data is currently available to assess the performance of physiological noise correction techniques, in particular when evaluating longitudinal changes in the default mode network (DMN) of healthy elderly participants. In this 3T harmonized multisite fMRI study, we investigated how different retrospective physiological noise correction (rPNC) methods influence the within-site test-retest reliability and the across-site reproducibility consistency of DMN-derived measurements across 13 MRI sites. Elderly participants were scanned twice at least a week apart (five participants per site). The rPNC methods were: none (NPC), Tissue-based regression, PESTICA and FSL-FIX. The DMN at the single subject level was robustly identified using ICA methods in all rPNC conditions. The methods significantly affected the mean z-scores and, albeit less markedly, the cluster-size in the DMN; in particular, FSL-FIX tended to increase the DMN z-scores compared to others. Within-site test-retest reliability was consistent across sites, with no differences across rPNC methods. The absolute percent errors were in the range of 5-11% for DMN z-scores and cluster-size reliability. DMN pattern overlap was in the range 60-65%. In particular, no rPNC method showed a significant reliability improvement relative to NPC. However, FSL-FIX and Tissue-based physiological correction methods showed both similar and significant improvements of reproducibility consistency across the consortium (ICC = 0.67) for the DMN z-scores relative to NPC. Overall these findings support the use of rPNC methods like tissue-based or FSL-FIX to characterize multisite longitudinal changes of intrinsic functional connectivity. Hum Brain Mapp 37:2114-2132, 2016. © 2016 Wiley Periodicals, Inc.

Longitudinal reproducibility of automatically segmented hippocampal subfields: A multisite European 3T study on healthy elderly

Recently, there has been an increased interest in the use of automatically segmented subfields of the human hippocampal formation derived from magnetic resonance imaging (MRI). However, little is known about the test-retest reproducibility of such measures, particularly in the context of multisite studies. Here, we report the reproducibility of automated Freesurfer hippocampal subfields segmentations in 65 healthy elderly enrolled in a consortium of 13 3T MRI sites (five subjects per site). Participants were scanned in two sessions (test and retest) at least one week apart. Each session included two anatomical 3D T1 MRI acquisitions harmonized in the consortium. We evaluated the test-retest reproducibility of subfields segmentation (i) to assess the effects of averaging two within-session T1 images and (ii) to compare subfields with whole hippocampus volume and spatial reliability. We found that within-session averaging of two T1 images significantly improved the reproducibility of all hippocampal subfields but not that of the whole hippocampus. Volumetric and spatial reproducibility across MRI sites were very good for the whole hippocampus, CA2-3, CA4-dentate gyrus (DG), subiculum (reproducibility error∼2% and DICE > 0.90), good for CA1 and presubiculum (reproducibility error ∼ 5% and DICE ∼ 0.90), and poorer for fimbria and hippocampal fissure (reproducibility error ∼ 15% and DICE < 0.80). Spearman's correlations confirmed that test-retest reproducibility improved with volume size. Despite considerable differences of MRI scanner configurations, we found consistent hippocampal subfields volumes estimation. CA2-3, CA4-DG, and sub-CA1 (subiculum, presubiculum, and CA1 pooled together) gave test-retest reproducibility similar to the whole hippocampus. Our findings suggest that the larger hippocampal subfields volume may be reliable longitudinal markers in multisite studies.

Value of 3 Tesla diffusion-weighted magnetic resonance imaging for assessing liver fibrosis

BACKGROUND

Limited data are available regarding the role of magnetic resonance imaging (MRI), particularly the new generation 3 Tesla technology, and especially diffusion-weighted imaging (DWI) in predicting liver fibrosis. The aim of our pilot study was to assess the clinical performance of the apparent diffusion coefficient (ADC) of liver parenchyma for the assessment of liver fibrosis in patients with non-alcoholic fatty liver disease (NAFLD).

METHODS

18 patients with biopsy-proven NAFLD underwent DWI with 3 Tesla MRI. DWI was performed with single-shot echo-planar technique at b values of 0-500 and 0-1000 s/mm². ADC was measured in four locations in the liver and the mean ADC value was used for analysis. Staging of fibrosis was performed according to the METAVIR system.

RESULTS

The median age of patients was 52 years (range 23-73). The distribution of patients in different fibrosis stages was: 0 (n=1), 1 (n=7), 2 (n=1), 3 (n=5), 4 (n=4). Fibrosis stage was poorly associated with ADC at b value of 0-500 s/mm² (r= -0.30, P=0.27). However it was significantly associated with ADC at b value of 0-1000 s/mm² (r= -0.57, P=0.01). For this b value (0-1000 s/mm²) the area under receiver-operating characteristic curve was 0.93 for fibrosis stage ≥3 and the optimal ADC cut-off value was 1.16 ×10^-3 mm²/s.

CONCLUSION

3 Tesla DWI can possibly predict the presence of advanced fibrosis in patients with NAFLD.

Imaging of brain tumors

Neuroimaging plays a crucial role in diagnosis of brain tumors and in the decision-making process for therapy. Functional imaging techniques can reflect cellular density (diffusion imaging), capillary density (perfusion techniques), and tissue biochemistry (magnetic resonance [MR] spectroscopy). In addition, cortical activation imaging (functional MR imaging) can identify various loci of eloquent cerebral cortical function. Combining these new tools can increase diagnostic specificity and confidence. Familiarity with conventional and advanced imaging findings facilitates accurate diagnosis, differentiation from other processes, and optimal patient treatment. This article is a practical synopsis of pathologic, clinical, and imaging spectra of most common brain tumors.

Manifestations of pilocytic astrocytoma: a pictorial review

BACKGROUND

Pilocytic astrocytoma can be challenging to diagnose.

METHODS

Its clinical presentations can differ, directly related to its size and location, and are relatively unreliable. Similarly, imaging findings also vary with the location of the pilocytic astrocytoma.

RESULTS

This review provides an overview of the different imaging findings regarding pilocytic astrocytomas using both conventional and advanced magnetic resonance imaging sequences according to tumour location; the findings are strongly related to the tumour's tendency to infiltrate surrounding structures, being able to carry out gross total resection, and finally the prognosis.

CONCLUSIONS

Knowledge of these imaging manifestations of pilocytic astrocytoma may be helpful to arrive at an accurate diagnosis.

TEACHING POINTS

• To recognise the various imaging findings of pilocytic astrocytoma on both conventional and advanced magnetic resonance imaging sequences. • To identify the characteristic imaging findings according to tumour location. • To discuss the relevant differential diagnoses of pilocytic astrocytoma in each tumour location.

Radiation-induced intracranial meningioma and multiple cavernomas

Brain irradiation has several well-known long-term side effects, including radiation-induced neoplasms and vasculopathy. In this case report, we describe an extremely rare case of meningioma and 15 cavernomas developing in a 29-year-old man, 19 years after cranial irradiation for posterior cranial fossa medulloblastoma. To our knowledge, this is the first case of a radiation-induced meningioma accompanied by this many radiation-induced cavernous angiomas.

Left atrial appendage occlusion with the Amplatzer Amulet for stroke prevention in atrial fibrillation: the first case in Greece

Left atrial appendage (LAA) occlusion has been introduced into clinical practice as a valuable alternative to oral anticoagulation for stroke prevention in patients with non-valvular atrial fibrillation. In this case presentation we describe the first LAA occlusion in Greece using the Amplatzer Amulet device. We also briefly discuss issues related to procedural safety and multimodality imaging for LAA occlusion.

Diagnostic performance of magnetic resonance arthrography of the shoulder in the evaluation of anteroinferior labrum abnormalities: a prospective study

OBJECTIVE

To evaluate the diagnostic performance of magnetic resonance (MR) arthrography of the shoulder in the diagnosis of anteroinferior labrum lesions, using arthroscopy as the reference standard and to classify these lesions.

METHODS

Institutional review board approval was obtained. The study population included 59 consecutive patients with history and clinical diagnosis of acute or chronic anterior shoulder instability. A total of 62 MR arthrograms were performed, since three patients had undergone a bilateral procedure. Arthroscopy, which was performed within a mean of 3 months (range 2-5 months) after MR arthrography, was used as the reference standard. Sensitivity, specificity, accuracy, positive and negative predictive values were then calculated.

RESULTS

MR arthrography showed a sensitivity of 96 % and a specificity of 80 % for the overall detection of anteroinferior labrum abnormalities. The diagnostic accuracy was 95 % and the positive and negative predictive values were 98 % and 66 % respectively. Ten lesions were non-classifiable on surgery, of which eight were non classifiable on MR arthrography also.

CONCLUSIONS

MR arthrography is highly accurate for the detection and classification of shoulder anteroinferior labrum lesions. Shoulder surgeons can confidently rely on this method to determine which patients will benefit from arthroscopy.

MAIN MESSAGES

• MR arthrography is accurate for the detection and classification of shoulder labrum lesions. • MR arthrography is a valuable tool for the preoperative planning in acute or chronic instability. • Shoulder surgeons can rely on this method to determine which patients will benefit from arthroscopy.

Dural lesions mimicking meningiomas: A pictorial essay

The purpose of this essay was to illustrate the radiological and pathological findings in a wide spectrum of dural lesions mimicking meningiomas. Familiarity with and knowledge of these findings will narrow the differential diagnosis and provide guidance for patient management. In this pictorial review, we describe the following entities: Solitary fibrous tumors, hemangiopericytoma, gliosarcoma, leiomyosarcoma, dural metastases, Hodgkin’s disease, plasmocytoma, Rosai-Dorfman disease, neurosarcoidosis, melanocytic neoplasms and plasma cell granuloma.

Transient contrast encephalopathy after carotid angiography mimicking diffuse subarachnoid haemorrhage

Neurotoxicity caused by intraarterial injection of low-dose low osmolar, iodinated contrast agents during radiologic studies is an extremely rare adverse event. Contrast medium induced disruption of the blood-brain barrier and a direct neurotoxic effect by contrast media have been proposed as a potential mechanism of neurotoxicity. This report describes an unusual case of transient neurotoxicity following diagnostic angiography mimicking clinically and radiologically subarachnoid hemorrhage. The patient recovered without any intervention after 4 days of conservative treatment.

Superficial cortical siderosis

Cerebrovascular deposition of amyloid (cerebral amyloid angiopathy CAA) is most commonly recognized as a cause of spontaneous lobar intracerebral hemorrhage. On the basis of the noninvasive new MR imaging we would propose superficial cortical hemosiderosis and subarachnoid hemosiderosis as potentially useful new criteria to facilitate the diagnosis of CAA.

The clinical presentation of Von Meyenburg complexes

Von Meyenburg Complexes (VMCs) is a rare clinicopathologic entity, consisting of small (<1.5cm), usually multiple and nodular cystic lesions. VMCs typically cause no symptoms or disturbances in liver function and thus in most instances they are diagnosed incidentally. We present four VMCs cases, each with a distinct clinical presentation. In two of our cases, VMCs caused mild, non-specific abdominal symptoms, including diffuse abdominal pain and discomfort. In the other two cases, in a 60-year-old woman and a 25-year-old man, the clinical presentation was implicative of an infectious hepatic process reminiscent of cholangitis and liver abscesses respectively. In each case the diagnosis was based on magnetic resonance imaging and magnetic resonance cholangiopancreatography findings showing multiple hyper-intense cystic nodules not communicating with the biliary tree. Physicians should be aware of the entire clinical spectrum of VMCs and its unique radiologic features in order to differentiate VMCs from other cystic liver lesions.

Magnetic resonance imaging findings in pseudo-Meigs' syndrome associated with a large uterine leiomyoma: a case report

Introduction

Pseudo-Meigs' syndrome is a rare pathological entity characterized by the presence of a pelvic mass other than an ovarian fibroma. The mass is associated with ascites with or without hydrothorax.

Case presentation

We describe the case of a 41-year-old Caucasian woman with a large uterine leiomyoma associated with massive ascites. A magnetic resonance imaging scan showed a large subserosal leiomyoma with multiple areas of cystic degeneration.

Conclusion

To the best of our knowledge, this is the first reported case of pseudo-Meigs' syndrome caused by a uterine leiomyoma and diagnosed using magnetic resonance imaging. The pathophysiology of this syndrome and the role of magnetic resonance imaging are emphasized in this case report.

Littoral cell angioma, a rare cause of long standing anaemia: a case report

Littoral cell angioma is a rare primary splenic tumor that is difficult to differentiate preoperatively from other benign and malignant splenic lesions. We report a case of littoral cell angioma of the spleen in a 51-year-old woman that presented with long standing anaemia.

Gastrointestinal stromal tumors: a pictorial review

We describe the pertinent organ-specific clinical manifestations of gastrointestinal stromal tumors (GISTs) as well as the radiological appearances that allow optimal depiction of pathology and diagnosis. Radiologic features of GISTs vary depending on tumor size and organ of origin. They most commonly have an exophytic growth pattern and manifest as dominant masses outside the organ of origin. Intramural and intraluminal masses are less common radiologic manifestations. GISTs may contain areas of hemorrhage, necrosis, or cyst formation that appear as focal areas of low attenuation on computed tomographic images. Most metastases of GISTs involve the liver and peritoneum by hematogenous spread and peritoneal seeding. CT and MRI are considered to be the imaging modality of choice for the detection, staging, surgical planning and follow-up of patients with GIST. A reduction in tumor size, extensive cystic changes, and calcification in primary and metastatic GISTs on CT and MRI indicate disease response to therapy. Radiologists and clinicians must recognize the imaging features of GISTs, detect, characterize the lesions and evaluate the tumor response during specific treatment.

Giant fibrovascular polyp of the oesophagus: a case report and review of the literature

Introduction

We present a case of fibrovascular polyp, a rare submucosal tumour of the oesophagus that has been reported only sporadically in the literature. The biapproach for surgical removal of fibrovascular polyp has only been mentioned once in the literature.

Case presentation

A 65-year-old Greek man presented with a 9-month history of gradually progressive intermittent dysphagia. Radiologic work-up with oesophagogram and computed tomography revealed a large, sausage-shaped intraluminal polyp extending from the level of the cervical oesophagus to the level of the upper body of the stomach. The diagnosis of giant fibrovascular polyp was made radiographically and confirmed by endoscopic biopsy. The polyp was removed using a biapproach surgical technique: pharyngotomy and subsequent gastrostomy.

Conclusion

Fibrovascular polyp is a rare submucosal tumour. Proper treatment depends on accurate assessment of the origin, size, and vascularity of the pedicle and the size of the tumour. Choice of the appropriate surgical approach depends on the correct diagnosis, which can usually be indicated radiographically by the presence of a smooth, sausage-shaped defect with a discrete bulbous tip.

Angiomatoid fibrous histiocytoma with cystic structures of sweat duct origin

Angiomatoid fibrous histiocytoma is an unusual soft tissue tumor, mostly arising in the subcutaneous fibro-adipose tissue of children and young adults and measuring a few centimeters in greatest dimension. Reported herein is a unique case of angiomatoid fibrous histiocytoma containing epithelium-lined cystic structures. This large tumor (12 cm) was located in the subcutaneous tissue of the left leg of a 28-year-old woman. The cystic structures were variably sized and were lined by a double cell layer with areas of squamous metaplasia. Their overall histological features suggested a sweat duct origin. Immunohistochemical stains confirmed such origin, demonstrating an inner epithelial and an outer myoepithelial (smooth muscle actin and cytokeratin 17 positive) cell layer. The present case is illustrative of a mechanism of sweat duct dilatation that may occur during the growth of neoplasms involving the dermis and subcutis, resulting in formation of tumors with unusual histological features.

Meningioma growth and interferon beta-1b treated multiple sclerosis: coincidence or relationship?

Although the coincidence of multiple sclerosis (MS) and central nervous system (CNS) tumors has been reported in over 30 cases in English literature, meningioma growth was associated with interferon-beta (INF-b) treated MS only in two of them. We report the case of a 19-year-old woman with clinically possible, laboratory supported MS, and a concomitant right intraventricular tumor with magnetic resonance imaging (MRI) characteristics consistent with meningioma (similar signal with grey matter on T1 and T2-weighted images and homogenous, intense enhancement). Two years after initiation of INF-b treatment, follow-up brain MRI revealed enlargement of the intraventricular mass and relative increase in the number of white matter lesions without significant clinical deterioration. She underwent almost total resection of the mass and histology confirmed the diagnosis of papillary meningioma. Based on the immunohistochemistry results, we speculate that INF-b resulted in meningioma growth by enhancing platelet derived growth factor (PDGF) receptors or/and down-regulating transforming growth factor receptors on the tumor itself.

Well-differentiated extraskeletal osteosarcomaReport of 2 cases, 1 with dedifferentiation

Extraskeletal osteosarcoma (ESOS) is a rare soft tissue sarcoma, typically characterized by high-grade histological features and a grave prognosis. However, 4 cases of well-differentiated ESOS with a better prognosis have been documented in the literature within the last 40 years. We report 2 additional cases, 1 with multicentric presentation and dedifferentiation, and we emphasize the histological features that are useful in distinguishing this lesion from other soft tissue tumors. Well-differentiated ESOS seems to represent a rare but distinct low-grade variant of ESOS. The limited published experience suggests that although the biologic behavior of this tumor is better than that of classical ESOS, there are cases with progression to a higher grade, leading eventually to final demise.

Extra-axial brain tumors

Meningiomas, schwannomas, metastases, maldevelopmental cysts, epidermoids, dermoids and bone tumors represent the vast majority of extra-axial brain tumors. The location of extra-axial brain tumors affects treatment planning and predicts their prognosis. Computed tomography and particularly magnetic resonance imaging are used for diagnosis and localization. In this article, the imaging findings of the extra-axial brain tumors are discussed.

Foci of decreased signal on T2-weighted MR images in leiomyosarcomas of soft tissue: correlation between MR and histological findings

OBJECTIVE

Leiomyosarcomas are rare soft tissue sarcomas with varying MR signal characteristics and histologic pictures. The purpose of this study was to investigate the histological features of foci, which showed decreased signal on T2-weighted images in leiomyosarcomas of soft tissue.

MATERIAL AND METHODS

We reviewed the MR images of six histologically proved cases of leiomyosarcomas of soft tissue and correlated the foci, which showed decreased signal on T2-weighted images with the histologic findings.

RESULT

Microscopic examination revealed that these foci were composed of hyalinization of neoplastic tissue, internal septations, deposition of hemosiderin, or corresponded to metaplastic bone.

CONCLUSION

The authors explain that the foci of decreased signal on T2-weighted MR images correspond to tissue components of the lesion, particularly fibrous tissue, hemosiderin and metaplastic bone. So, the suggestion is that leiomyosarcoma should be considered in the differential diagnosis of soft-tissue tumors that show foci of decreased signal on T2-weighted MR images.

Lipomatous tumors of soft tissue: MR appearance with histological correlation

There is a broad spectrum of lipomatous tumors that involve soft tissues including ordinary lipomas, variants of lipomas, heterotopic lipomas, lipomatosis, hibernomas and liposarcomas. The recognition of these tumors is important to avoid diagnostic pitfalls. The MR imaging appearance of the lesion, including location, shape and internal architecture, suggests the diagnosis of lipomatous tumors. The signal intensity on T1-, T2-, fat-suppressed T2-weighted (FS-T2) images or short tau inversion recovery (STIR), T1- and fat-suppressed T1-weighted images after Gd-DTPA administration can be a useful aid in distinguishing between biologically different types of lipomatous tumors. The imaging features are often characteristic and reflect the histological pattern of the tumors. We present an overview of the lipomatous tumors and we correlate MR imaging appearance with histological findings.

Imaging of primary bone tumors of the spine

Primary tumors of the spine are relatively infrequent lesions compared with metastatic disease, multiple myeloma, and lymphoma. A wide variety of benign and malignant neoplasms can involve the spine. The imaging features of these lesions are often characteristic. We present an overview of the imaging modalities in primary tumors of the spine in order to provide a useful tool in current radiologic practice. The role of CT and MRI is discussed.

CT and MR imaging findings in cerebral toxocaral disease

We report serial MR findings in a 54-year-old woman with eosinophilic meningoencephalitis due to Toxocara canis infection, a parasitic disease contracted through exposure with soil contaminated by the eggs of the roundworm. MR imaging revealed several enhancing subcortical and white matter lesions in both lobes. Antihelminthic chemotherapy yielded marked improvement of the neurologic deficits and cerebral lesions. The specific MR findings-low signal intensity on T1-weighted images, high signal intensity on T2-weighted images, and contrast enhancement-and the clinical and epidemiologic features of CNS involvement are herein reviewed.

Mediastinal germ cell tumors: a radiologic-pathologic review

Germ cell tumors of the mediastinum are histologically identical to those found in the testes and ovaries. Early diagnosis and treatment improve the survival rate. Imaging studies of teratoma demonstrate a rounded, often lobulated heterogeneous mass containing soft tissue elements with fluid and fat attenuation. Calcification is present in 20-43% of cases. Seminomas are large masses of homogeneous soft tissue attenuation. Malignant nonseminomatous germ cell tumors are heterogeneous tumors with irregular borders due to invasion of adjacent structures. CT shows the location and extent of the tumors as well as intrinsic elements including soft tissue, fat, fluid, and calcification. CT is the modality of choice for the diagnostic evaluation of these tumors. MRI reveals masses of heterogeneous signal intensity, is more sensitive in depicting infiltration of the adjacent structures by fat plane obliteration, and is performed as an ancillary study.