Reliability of fast-spin echo T2-weighted three-dimensional sequences to predict endoscopic third ventriculocisternostomy patency in children.

PURPOSE: Clinical and radiological assessment of endoscopic third ventriculocisternostomy (ETV) patency can be challenging in children. The objective of our study was thus to test the accuracy and interrater reliability of 3D fast-spin echo (FSE) T2-weighted sequences to assess the patency of ETV. METHODS: We included all the consecutive children who underwent surgery for ETV over a two-year period and selected the children who presented ETV dysfunction and matched them with children without dysfunction. We evaluated the Kappa interrater reliability of three experienced physicians for prediction of ETV patency using solely the flow void sign in 3D FSE T2-weighted sequences. RESULTS: Nineteen children underwent surgery for ETV dysfunction and 12 children without dysfunction were matched. Sensitivity was 0.79, 0.89 and 0.84 and specificity was 1 for all raters. None of the patent ETV was wrongly considered to be dysfunctional. Fleiss' kappa was 0.871 (p < 0.001). The interrater reliability was excellent with respect to the patency or not of the ETV. CONCLUSION: FSE T2-weighted sequence is a simple and reproducible tool that can be widely used in daily practice to assess the patency of ETV. Interrater reliability of this sequence is high and accessibility in outpatient setting is acceptable.

Features of the choriocapillaris on four different optical coherence tomography angiography devices.

PURPOSE: To investigate the features of the choriocapillaris using four different optical coherence tomography angiography (OCTA) devices. METHODS: OCTA images of the choriocapillaris from consecutive healthy subjects were obtained with four different OCTA devices (Zeiss PLEX Elite, Topcon DRI OCT-1 Atlantis, Zeiss AngioPlex, and Heidelberg Spectralis OCTA). The 3 × 3 mm OCTA images were processed with ImageJ. The mean vascular density and mean flow void area of the choriocapillaris were compared among devices. Flow voids were analyzed with two different imaging adjustment methods, auto-local threshold with the Phansalkar method and a method using a device-specific threshold value. RESULTS: The mean vascular density of the choriocapillaris differed among the four devices (all P < 0.001). The mean flow void area as measured with the auto-local threshold method also differed among devices (P < 0.001) and was not correlated among devices (all P > 0.05). Results for mean flow void area measured with a device-specific threshold value using the Plex-Elite and DRI OCT-1 Atlantis were correlated (ß = 2.271, P < 0.001), but there were no correlations among other devices (P > 0.05). For the Plex-Elite and DRI OCT-1 Atlantis, the mean flow void area was positively correlated between the two image adjustment methods (all P < 0.05). CONCLUSIONS: Vascular densities and flow void areas of the choriocapillaris varied according to the device used and the image adjustment method. The characteristics of different devices and the image adjustment method should be considered for analysis of the choriocapillaris.

Management of pituicytomas: a multicenter series of eight cases.

PURPOSE: Pituicytomas and spindle cell oncocytomas (SCOs) are two rare neoplasms of the sellar and suprasellar region, known to be challenging as they are extremely vascular and almost always misdiagnosed, altering our surgical planning and the patients' outcomes. Also we argue that recent update concerning the pathology findings of these tumors should be more widely generalized to our practice. METHODS: This is a retrospective multicenter study, reporting the clinical manifestations, radiological characteristics, histopathological features, treatment strategies and long-term outcomes of patients who have been treated for a Pituicytoma at various institutions in Paris, France over the past 10 years. In addition, we compared our results to the world literature in order to identify similarities concerning the radiographic diagnosis and the treatment strategies of these tumors. RESULTS: Eight patients were operated on in four different hospitals. Misdiagnosis was constant before surgery, pituitary adenoma or craniopharyngioma being suspected. During surgery (transsphenoidal approach: six cases, transcranial approach: two cases) unusual tumors were noted, with important bleeding in most cases. Complete resection could be obtained in five patients. Pathological diagnosis was confirmed in all cases. During the follow up two recurrences occurred. One was subsequently treated with radiotherapy, the other underwent a second surgery. CONCLUSION: Recent updates concerning the histological diagnosis of pituicytomas should be generalized to our practice in order to provide a better understanding of this rare pathology and its natural course.

Papillary meningioma with prominent flow voids.

This report presents an extremely rare case of papillary meningioma with prominent flow voids and increased perfusion parameters on MRI in a 28-year-old male presenting with headache. This knowledge helped the neurosurgeon to minimise intra-operative blood loss and achieve a favourable post-surgical outcome. Contribution: A rare case of papillary meningioma and its differentiating features from typical meningiomas have been discussed considering its implications for management as well as prognostication to reduce morbidity and mortality.

[Multiple dural arteriovenous fistulas showing isolated subcortical white matter T2 hyperintensity with gadolinium enhancement].

We describe a 44-year-old man with a complaint of atonic seizures of the left upper limb, followed by generalized seizures. Brain MRI showed isolated juxtacortical white matter T2 hyperintensity with gadolinium (Gd) enhancement of the adjacent cortical gray matter and subcortical white matter in the right frontal convexity. Treatment with levetiracetam was effective for seizure suppression, and he had no other neurological abnormalities. Human leukocyte antigen typing revealed B54 and Cw1, which indicated the possibility of neuro-Sweet disease. However, a general examination, which included vital signs and eye and skin findings, was normal. A cerebrospinal fluid test showed a mild elevation in protein levels without pleocytosis and a normal range of interleukin-6. Electroencephalography showed intermittent slow waves without epileptic discharge in the bilateral temporal lobes. We detected subtle flow voids in the pia mater of the left frontal lobe, which suggested cerebrovascular disease, and specifically, the possibility of dural arteriovenous fistulas. Computed tomography angiography showed abnormally dilated perimedullary veins in the left frontal lobe. Cerebral angiography confirmed the existence of four dural arteriovenous fistulas, which included two retrograde leptomeningeal venous drainages in the right frontal cortical veins supplied by the anterior branch of the right middle meningeal artery. The other dural arteriovenous fistulas were retrograde leptomeningeal venous drainages in the left frontal cortical veins supplied by the anterior and posterior convexity branches of the left middle meningeal artery. The patient underwent successful endovascular embolization of all dural arteriovenous fistulas with Onyx injection. A follow-up MRI showed gradual improvement of the T2 hyperintensity and Gd enhancement. He remained seizure-free for 2 years following endovascular embolization.

Diffusion lacunae: a novel MR imaging finding on diffusion-weighted imaging for diagnosing placenta accreta spectrum.

OBJECTIVE: To evaluate the usefulness of novel diffusion-weighted imaging (DWI) findings for diagnosing placenta accreta spectrum (PAS). MATERIALS AND METHODS: This retrospective study included 49 pregnant women with suspected PAS who underwent 1.5 T placental MRI. Diffusion lacunae were defined as intraplacental areas showing hypointensity on DWI and hyperintensity on the apparent diffusion coefficient map. Two radiologists evaluated the number and size of placental lacunae on DWI, and flow void in the diffusion lacunae on T2-weighted imaging. The radiologists also evaluated established MRI features of PAS described in the SAR-ESUR consensus statement. Pearson's chi-square test or Mann-Whitney U test was used to compare findings between patients with and without PAS. Interobserver reliability for DWI and established MRI features was also assessed. Optimal thresholds for the number and maximum size of diffusion lacunae for differentiating PAS from the no-PAS group were determined using receiver operating characteristic curve analyses. RESULTS: Eighteen patients were diagnosed with PAS, and 31 patients with placental previa without PAS. The number and maximum size of diffusion lacunae were significantly larger in patients with than in patients without PAS (p < 0.0001). Combining assessment of the number of diffusion lacunae with assessment of their maximum size yielded a diagnostic performance with sensitivity, specificity and accuracy of 83%, 94% and 90%, respectively. Flow voids within the diffusion lacunae had sensitivity, specificity and accuracy of 88%, 84% and 86%, respectively. CONCLUSION: The number and size of diffusion lacunae, and T2 flow void in diffusion lacunae may be useful findings for diagnosing PAS.

Artifact-Removed Quantitative Analysis of Choriocapillaris Flow Voids.

Objectives: To investigate choriocapillaris flow voids (FV) with a new optical coherence tomography angiography (OCTA) image processing strategy that can eliminate artifacts caused by vitreous opacities, sub-retinal pigment epithelium fluid and deposits, and subretinal fluid (SRF) by thresholding the en-face OCT image of the outer retina. Materials and Methods: We retrospectively reviewed medical records of patients with drusen and patients with active central serous chorioretinopathy (CSC). FV number (FVn), average area (FVav), and maximum area (FVmax) and the percentage of nonperfused choriocapillaris area (PNPCA) obtained using the proposed strategy were compared with those obtained by removing only artifacts caused by the superficial capillary plexus (SCP). Results: The SRF group included 21 eyes with active CSC and the drusen group included 29 eyes with nonexudative age-related macular degeneration. FVav, FVmax, FVn, and PNPCA obtained using the algorithm were significantly lower than those obtained by removing only SCP-related artefacts in both groups (all p<0.05). The algorithm was also able to remove 96.9% of artifacts secondary to vitreous opacities and all artifacts secondary to serous pigment epithelial detachments. Conclusion: Choriocapillaris nonperfusion areas on OCTA images may be overestimated in eyes with RPE abnormalities and SRF due to artifacts. These artifact areas on choriocapillaris OCTA images can be removed using thresholded images of the outer retina en-face OCT scans. Our new artifact-removal strategy is useful in the assessment of choriocapillaris FV in eyes with SRF, drusen, drusen-like deposits, and pigment epithelial detachment.

Fully automatic segmentation and monitoring of choriocapillaris flow voids in OCTA images.

Optical coherence tomography angiography (OCTA) is a non-invasive ophthalmic imaging modality that is widely used in clinical practice. Recent technological advances in OCTA allow imaging of blood flow deeper than the retinal layers, at the level of the choriocapillaris (CC), where a granular image is obtained showing a pattern of bright areas, representing blood flow, and a pattern of small dark regions, called flow voids (FVs). Several clinical studies have reported a close correlation between abnormal FVs distribution and multiple diseases, so quantifying changes in FVs distribution in CC has become an area of interest for many clinicians. However, CC OCTA images present very complex features that make it difficult to correctly compare FVs during the monitoring of a patient. In this work, we propose fully automatic approaches for the segmentation and monitoring of FVs in CC OCTA images. First, a baseline approach, in which a fully automatic segmentation methodology based on local contrast enhancement and global thresholding is proposed to segment FVs and measure changes in their distribution in a straightforward manner. Second, a robust approach in which, prior to the use of our segmentation methodology, an unsupervised trained neural network is used to perform a deformable registration that aligns inconsistencies between images acquired at different time instants. The proposed approaches were tested with CC OCTA images collected during a clinical study on the response to photodynamic therapy in patients affected by chronic central serous chorioretinopathy (CSC), demonstrating their clinical utility. The results showed that both approaches are accurate and robust, surpassing the state of the art, therefore improving the efficacy of FVs as a biomarker to monitor the patient treatments. This gives great potential for the clinical use of our methods, with the possibility of extending their use to other pathologies or treatments associated with this type of imaging.

Botulinum toxin type A in multimodal management of age-related macular degeneration and related diseases.

Age related macular degeneration (AMD) is the major cause of visual loss in the aging population in the Western world. In past decade, intra ocular injections of anti-vascular endothelial growth factor (anti-VEGF) pharmaceuticals have revolutionized therapy for exudative (edematous-wet) AMD and become standard practice for the near term. However repeated intra-ocular injections are required for years and long terms results have been limited. The pathogenesis of this condition is multifactorial involving genetic, ischemic, inflammatory factors leading to neovascularization, edema and retinal pigment epithelial scaring resulting in photoreceptor destruction. Based on coincidental observation in reduction in AMD related macular edema on ocular coherence tomography (OCT) in a BoNT A treated patient with facial movement disease, BoNT-A at conventional doses targeting the para orbital area was added to therapeutic regiment in a small number of patients with exudative macular degeneration or related diseases. Measurements of edema and choriocapillaris using Spectral Doman (OCT) and Ocular Coherence Angiography (OCT-A) and Snellen visual acuity were made over the evaluation period. 15 eyes in 14 patients averaged 361 µm central sub foveal edema (CSFT) pre injection and average of 266 µm (CSFT) post injection over an average of 21 months and 5.7 cycles using BoNT A alone at conventional doses (n = 86 post injection measurements, paired t-test p < 0.001 two tailed). Visions at baseline in patients with 20/40 or worse averaged 20/100- pre injection improved to an average of 20/40- in the post injection period (n = 49 measurements p < 0.002 paired t-test). The previous data was added to a group of 12 more severely afflicted patients receiving anti VEGF (aflibercept or bevacizumab) (total 27 patients). With this 27-patient group, patients were followed for an average of 20 months and receiving average of 6 cycles at conventional doses. Improvement in exudative edema and vision were noted with pre injection baseline CSFT average 399.5, post injection average 267, n = 303 post measurement, independent t-test P < 0.0001.). Snellen vision 20/128 baseline average improved to average of 20/60- during post injection period (n = 157 post injection measurements, p < 0.0001 paired t-test to baseline). No substantial adverse effects were noted. Cyclic effects were noted corresponding to duration of action of BoNT-A on a number of patients. The above data is preliminary and is skewed toward early leakage for all conditions. BoNT A may have a role in the treatment of aged related macular degeneration. Controlled studies are needed with careful staging and baseline stratifications for multi-modal management paradigms. The findings are discussed relative to known botulinum toxin type A pharmacology and AMD pathogenesis.

Spinal Epidural Lipomatosis Associated with Intrathecal Flow Voids: Demonstration of Engorged Veins Using Flat Panel Catheter Angiotomography.

We present a case of a 54-year-old male with spinal epidural lipomatosis who had associated flow voids on magnetic resonance imaging with dilated intrathecal vessels. During spinal angiogram, 20s DynaCT (flat panel catheter angiotomography) was utilized to demonstrate the intrathecal engorged veins. Venous engorgement of epidural venous plexus has been previously described in epidural lipomatosis; however, dilated intrathecal perimedullary veins have not been demonstrated by imaging. We have described the utility of flat panel catheter angiotomography in understanding venous disorders in such patients.

Reversible Choriocapillaris Flow Voids in Acute Syphilitic Posterior Placoid Chorioretinitis.

PURPOSE: To report two cases of acute syphilitic posterior placoid chorioretinitis (ASPPC) with choriocapillaris flow voids that partially resolved with systemic antibiotic treatment. METHODS: Observational case report with multimodal imaging. RESULTS: Two young healthy men suffered an acute monocular loss of vision. Spectral domain optical coherence tomography (SD-OCT) and OCT angiography (OCT-A) revealed outer retinitis with loss of the ellipsoid layer and choriocapillaris flow voids. Systemic work-up revealed syphilis. Upon systemic treatment with antibiotics, the patients recovered their vision and the OCT and OCT-A abnormalities partially resolved. CONCLUSIONS: Transient choriocapillaris flow voids characterize ASPPC and may be responsible for the visual loss seen in these patients.

Alveolar soft part sarcoma of the orbit: A case report.

Alveolar soft part sarcoma is a rare soft tissue neoplasm that accounts for approximately 1% of all sarcomas and is usually identified in the extremities in adults. The occurrence of alveolar soft part sarcoma in the orbit is extremely rare, estimated at approximately 5% - 15% among all cases of alveolar soft part sarcoma . Here, we present a case of 29-year-old woman with orbital alveolar soft part sarcoma. We describe the magnetic resonance and F-18 2-fluoro-2-deoxy-D-glucose-position emission tomography/computed tomography findings of this case. This young woman had a spindle-shaped mass. A higher signal compared to the extraocular muscle on T1-weighted images, numerous flow voids on T2-weighted images, and intense enhancement could be key findings of this disease.

Microvasculature Features of Vogt-Koyanagi-Harada Disease Revealed by Widefield Swept-Source Optical Coherence Tomography Angiography.

Background: Vogt-Koyanagi-Harada (VKH) disease is a multisystem autoimmune disorder which could induce bilateral panuveitis involving the posterior pole and peripheral fundus. Optical coherence tomography angiography (OCTA) provides several advantages over traditional fluorescence angiography for revealing pathological abnormalities of the retinal vasculature. Until recently, however, the OCTA field of view (FOV) was limited to 6 × 6 mm2 scans. Purpose: This study examined retinal vasculature and choriocapillaris abnormalities across multiple regions of the retina (15 × 9 mm2 wide field, macular, peripapillary regions) among acute and convalescent VKH patients using a novel widefield swept-source OCTA (WSS-OCTA) device and assessed correlations between imaging features and best-corrected visual acuity (BCVA). Methods: Twenty eyes of 13 VHK disease patients in the acute phase, 30 eyes of 17 patients in the convalescent phase, and 30 eyes of 15 healthy controls (HCs) were included in this study. Vascular length density (VLD) in superficial and deep vascular plexuses (SVP, DVP), vascular perfusion density (VPD) in SVP, DVP, and choriocapillaris (CC), and flow voids (FV) in CC were measured across multiple retinal regions via WSS-OCTA (PLEX Elite 9000, Carl Zeiss Meditec Inc., USA) using the 15 × 9 mm2 scan pattern centered on the fovea and quantified by ImageJ. Results: Compared to HCs, acute phase VKH patients exhibited significantly reduced SVP-VLD, SVP-VPD, and CC-VPD across multiple retinal regions (all p < 0.01). Notably, the FV area was more extensive in VKH patients, especially those in the acute phase (p < 0.01). These changes were reversed in the convalescent phase. Stepwise multiple linear regression analysis demonstrated that macular DVP-VLD and macular CC-VPD were the best predictive factors for BCVA in the acute and convalescent VKH groups. Conclusion: The wider field of SS-OCAT provides more comprehensive and detailed images of the microvasculature abnormalities characterizing VKH disease. The quantifiable and layer-specific information from OCTA allows for the identification of sensitive and specific imaging markers for prognosis and treatment guidance, highlighting WSS-OCTA as a promising modality for the clinical management of VKH disease.

Optical Coherence Tomography Angiography Findings in Optic Nerve Sheath Meningioma.

A 46-year-old female with a history of 5 months of progressive painless visual loss in the left eye was found to have an optic nerve sheath meningioma. Optical coherence tomography angiography showed a reduction in the superficial capillary plexus density consistent with her visual field defect and peripapillary retinal nerve fiber layer thinning. Moreover, abnormalities in the choriocapillaris were found in the affected eye compared to the fellow eye. Possible explanations for these findings are discussed. Further studies and a consistent number of cases are needed to correctly assess the impairment of ocular blood flow in optic nerve sheath meningioma.

Optical Coherence Tomography Angiography in Diabetes and Diabetic Retinopathy.

Diabetic retinopathy (DR) is a common complication of diabetes mellitus that disrupts the retinal microvasculature and is a leading cause of vision loss globally. Recently, optical coherence tomography angiography (OCTA) has been developed to image the retinal microvasculature, by generating 3-dimensional images based on the motion contrast of circulating blood cells. OCTA offers numerous benefits over traditional fluorescein angiography in visualizing the retinal vasculature in that it is non-invasive and safer; while its depth-resolved ability makes it possible to visualize the finer capillaries of the retinal capillary plexuses and choriocapillaris. High-quality OCTA images have also enabled the visualization of features associated with DR, including microaneurysms and neovascularization and the quantification of alterations in retinal capillary and choriocapillaris, thereby suggesting a promising role for OCTA as an objective technology for accurate DR classification. Of interest is the potential of OCTA to examine the effect of DR on individual retinal layers, and to detect DR even before it is clinically detectable on fundus examination. We will focus the review on the clinical applicability of OCTA derived quantitative metrics that appear to be clinically relevant to the diagnosis, classification, and management of patients with diabetes or DR. Future studies with longitudinal design of multiethnic multicenter populations, as well as the inclusion of pertinent systemic information that may affect vascular changes, will improve our understanding on the benefit of OCTA biomarkers in the detection and progression of DR.

Syringomyelia Associated with Spinal Dural Arteriovenous Fistula: Clinical and Radiological Improvement after Embolization.

Spinal dural arteriovenous fistulae (AVF) are rare and can result in spinal cord dysfunction. We present one such case wherein the patient presented with a venous congestive myelopathy. Magnetic resonance imaging showed a syrinx formation, spinal cord edema, and flow voids. Digital subtraction angiography confirmed the dural AVF, which was treated with embolization. The syrinx disappeared, other spinal cord changes improved, and the patient had remarkable clinical improvement. The case is presented to draw attention to the rare formation of a syrinx in a spinal dural arteriovenous fistula and its disappearance after successful embolization.

Quantitative choriocapillaris evaluation in intermediate age-related macular degeneration by swept-source optical coherence tomography angiography.

PURPOSE: To investigate choriocapillaris (CC) perfusion, by evaluating flow voids (FV), in eyes with intermediate age-related macular degeneration (iAMD) using swept-source optical coherence tomography angiography (SS-OCT-A). METHODS: Patients with bilateral or unilateral iAMD and normal controls underwent SS-OCT and OCT-A examination. Choriocapillaris (CC) FVs were quantitatively assessed on OCT-A images using matlab (version 2017b; MathWorks, Natick, MA, USA), after a preprocessing aimed at compensating for CC attenuation artefacts. Three different thresholds [1 standard deviation (SD), 1.25 SD and 1.5 SD] were applied. Final FV percentage (FV%) was calculated as the ratio between area with absent flow and total scanned area. RESULTS: Of 41 patients with iAMD and 16 normal subjects enrolled in the study, 39 eyes (39 patients) with iAMD and all 16 normal eyes (16 control subjects) were included in the final analysis. Mean FV% (1 SD) was 13.45 ± 0.66 in controls, 14.19 ± 1.23 in bilateral iAMD and 14.21 ± 0.99 in unilateral iAMD (p = 0.03, for difference between controls and bilateral iAMD). Mean FV% (1.25 SD) was 6.55 ± 0.65 in controls, 7.33 ± 1.4 in bilateral iAMD and 7.06 ± 1.4 in unilateral iAMD (p = 0.048, for difference between controls and bilateral iAMD). Mean FV% (1.5 SD) was 2.71 ± 0.82 in controls, 2.55 ± 1.12 in bilateral iAMD and 3.25 ± 1.17 in unilateral iAMD (p = 0.038, for difference between bilateral and unilateral iAMD). CONCLUSION: A significantly higher FV% was found in patients with iAMD versus controls. A higher trend in FV% was found in unilateral iAMD (with neovascular AMD in the fellow eye) versus bilateral iAMD, when applying the lowest threshold. Further, larger and longitudinal studies are needed to confirm this data.

Abnormal vascularization of soft-tissue sarcomas on conventional MRI: Diagnostic and prognostic values.

PURPOSE: To assess the prevalence of abnormal vessels inside and surrounding soft-tissue sarcomas (STS) on conventional MRIs so as to evaluate their correlations with particular histotypes, histological grades, and prognosis. METHOD: This single-center retrospective study included 157 adult patients (median age: 61) with histologically-proven non-metastatic STS. All had pre-treatment conventional contrast-enhanced MRI. Two radiologists reported: presence of abnormal flow-voids, number and distribution (peri-tumoral and/or intra-tumoral), percentage of tumor circumference it covered, maximal diameter. The radiological findings were correlated with histopathology. Associations were evaluated with Chi-2 or t-tests. Survival analysis (for metastasis-free survival (MFS) and overall survival (OS)) included log-rank tests and multivariate Cox-model. RESULTS: Twenty-nine of 157 (18.5%) STS showed abnormal flow-voids that were peri-tumoral (9/157, 5.7%), intra-tumoral (5/157, 3.2%) or both intra- and peri-tumoral (15/157, 9.6%). Ten STS had more than 5 flow-voids, all being grade II-III, namely: 4 undifferentiated sarcomas, 2 solitary fibrous tumors, 1 alveolar soft-part sarcoma (ASPS), 2 leiomyosarcomas and 1 pleomorphic liposarcoma. The distribution of flow-voids was associated with survivals in the univariate analysis: patients with abnormal peritumoral flow-voids (APTFV) showed poorer OS and MFS (p = 0.039 and 0.014, respectively). These associations did not remain significant in multivariate analysis. Radio-pathological correlations revealed large tortuous tumoral neo-vessels with intra-vascular thrombi of tumor cells in ASPS and in one case of undifferentiated sarcoma displaying enrichment in genes involved in neo-angiogenesis at transcriptional level. CONCLUSIONS: APTFV on conventional MRIs may be associated with a higher risk of metastatic relapse and poorer OS in STS patients.

First Depiction of Flow Voids to Differentiate Pituicytomas from Giant Adenomas.

Pituicytomas are rare low-grade glial lesions of neurohypophysis or adenohypophysis. They are often misdiagnosed as adenomas due to their similar morphology. Previous reports have underlined their nonspecific aspect. In our experience, presence of flow voids on magnetic resonance, which usually indicate hypervascularized tumors with strong arterial supply, may be a useful sign to identify pituicytomas. Unlike adenomas, pituicytomas are highly vascularized tumors. Second, we emphasize the strong enhancement of these tumors when compared with normal hypophysis, which may be another sign of their hypervascularization. Indeed, adenomas, on the opposite side, present less enhancement than normal hypophysis. This observation is corroborated by previous histologic studies that showed adenomas present less vascular density than normal pituitary glands. However, in large tumors, the normal hypophysis can sometimes not be individualized and thus the enhancement gradient between the tumor and normal tissue cannot be properly assessed. Due to their rarity, no previous reports had ever emphasized the specific signs that could allow us to differentiate pituicytomas from adenomas; however, it seems crucial due to the potential hemorrhagic complications of pituicytoma surgery.

Magnetic Resonance Features and Characteristic Vascular Pattern of Alveolar Soft-Part Sarcoma.

OBJECTIVE: The aim of this study was to investigate the magnetic resonance (MR) features of alveolar soft-part sarcoma (ASPS). METHODS: We studied 12 patients with ASPS confirmed by pathology in this retrospective study. MR features were analyzed, especially for the location, morphology, signals, and related enhanced features of the tumor vessels. RESULTS: Flow voids were shown in the central part of the tumor on T2-weighted imaging (T2WI) in all patients; they were arrayed in a radiating mode gathered toward the center (8 cases), designated by us as vascular center-gathered syndrome (VCGS), or scattered like twigs (4 cases). The flow voids were accompanied by high signals in all patients, including tubular (6 cases) and platy (6 cases) signals. Slightly higher signals were shown in the peripheral part of the tumor in all patients. Flow voids in the peripheral part were shown in all patients, and the majority of the flow voids surrounded the tumor (8 cases). The vessels around the tumor in 9 patients showed high signals, and the majority of the vessels were located at the superior and inferior poles (8 cases). 6 patients underwent enhanced scanning, including moderate (5 cases) and significant enhancement (1 case). CONCLUSION: Low signals of radiating flow voids accompanied by high signals of slow blood flow or blood sinuses in the center part have high significance for the diagnosis of ASPS.