When is pre-operative imaging required for craniofacial dermoid cysts/sinuses? A review.

OBJECTIVES: Dermoid cysts/sinuses (DCS) are congenital masses occurring along lines of embryonic fusion. Midline DCS carry a risk of intracranial extension. Pre-operative computed tomography (CT) or magnetic resonance imaging (MRI) are the primary imaging modalities used and based on the results, the need to involve a neurosurgical team in the resection is determined. Although less so, non-midline locations are also at risk for intracranial communication. This study aims to quantify our institutional experience with both midline and lateral DCS for intracranial extension and discuss potential need for preoperative imaging in all DCS cases. METHODS: Institutional Review Board approval was obtained. Pediatric patients ages 0-18 years with DCS presenting to the pediatric otolaryngology, plastic surgery, and neurosurgery clinics from 2005 to 2020 were retrospectively reviewed. Data collected included patient demographics, imaging modality, location, size, complications, and presence/absence of intracranial extension. DCS location included nasoethmoidal (NE), periorbital, frontotemporal (FT), and scalp. Lesions were further classified as midline and non-midline. RESULTS: 205 patients with surgically removed DCS were included for analysis. Mean age at surgery was 3 years. MRI was the most common imaging modality used (60.5%), followed by US (18%), CT (18%) and plain films (1%). Locations were: NE (69, 34%), periorbital (67, 33%), FT (28, 14%), and scalp (41, 20%). 105 DCS were midline: NE (69), periorbital (7), and scalp (29). Of these, 29 (28%) had intracranial extension: NE (8), scalp (21). 100 DCS were non-midline: periorbital (60), FT (28) and scalp (12). Of these, 7 (7%) had intracranial extension: periorbital (3), FT (3) and scalp (1). CONCLUSION: The risk of intracranial extension of midline craniofacial DCS is well established. We have shown that there is a percentage of lateral DCS which carry a risk for intracranial extension, and for which the involvement of a neurosurgical team may be required. Given the potential benefit, pre-operative imaging of all lateral head and neck DCS may be prudent to screen for intracranial extension.

Mucoepidermoid Carcinomas of the Larynx.

OBJECTIVES: Discussions regarding the specific management and outcomes for laryngeal MEC are limited to very small, single-institution case series. To look further into the diagnosis and management of these uncommon non-squamous cell carcinomas of the larynx, we present 3 recent cases of laryngeal MEC treated at our institution. METHODS: Patients at a tertiary hospital treated for MEC between October 2019 and December 2020 were retrospectively identified. Chart review, imaging analysis, and histologic slide creation were completed for all patients. RESULTS: We identified and treated 2 patients with high-grade supraglottic and 1 patient with intermediate-grade glottic MEC. These patients presented to our clinic with a primary complaint of either gradual, worsening dysphonia, dysphagia, or both. All patients underwent laryngovideostroboscopy as well as panendoscopy with directed submucosal biopsy, which was consistent with MEC. MRI was performed in 2 of the cases further elucidating the extent of submucosal spread. PET-CT was performed in all 3 cases, and none demonstrated evidence of regional or distal metastases. Surgically, high-grade MEC lesions were treated with a total laryngectomy. The intermediate MEC lesion was managed with a supracricoid partial laryngectomy (SCPL). Surgical margins were free of tumor in all cases with no nodal metastases by modified radical neck dissection. Radiation therapy was offered to both high-grade MEC patients and declined by one. Radiation was not recommended to the patient with intermediate-grade MEC as we believed that the risk of additional treatment outweighed the benefit. CONCLUSION: We believe that MEC of the larynx should be considered in patients with atypical submucosal laryngeal masses. Laryngovideostroboscopy, MRI, and PET imaging may be valuable in determining the extent of the lesions and planning appropriate surgery. Postoperative radiation therapy should be considered a per tumor grade in other more studied sites, as there is no data on efficacy in laryngeal MEC.

MRI and PET of Brain Tumor Neuroinflammation in the Era of Immunotherapy, From the AJR Special Series on Inflammation.

With the emergence of immune-modulating therapies, brain tumors present important diagnostic imaging challenges. These challenges include planning personalized treatment and adjudicating accurate monitoring approaches and therapeutically specific response criteria. The challenges have been due, in part reliance on nonspecific imaging metrics, such as gadolinium contrast-enhanced MRI or FDG PET, and rapidly evolving biologic understanding of neuroinflammation. The importance of the tumor immune interaction and ability to therapeutically augment inflammation to improve clinical outcomes make it necessary for radiologists to develop a working knowledge of the immune system and its role in clinical neuroimaging. The purpose of this article is to review relevant biologic concepts of the tumor microenvironment of primary and metastatic brain tumors, the interactions between the tumors and the immune system, and MRI and PET methods for imaging inflammatory elements associated with these malignancies. In recognition of the growing fields of immunotherapeutics and precision oncology, clinically translatable imaging metrics for the diagnosis and monitoring of brain tumor neuroinflammation are highlighted. Practical guidance is provided for implementing iron nanoparticle imaging, including imaging indications, protocols, interpretation, and pitfalls. A comprehensive understanding of the inflammatory mechanisms within brain tumors and their imaging features will facilitate the development of innovative noninvasive prognostic and predictive imaging strategies for precision oncology.

Non-specific orbital inflammation: Current understanding and unmet needs.

Non-specific orbital inflammation (NSOI) is a noninfectious inflammatory condition of the orbit. Although it is generally considered the most common diagnosis derived from an orbital biopsy, it is a diagnosis of exclusion, meaning that the diagnosis requires exclusion of a systemic process or another identifiable etiology of orbital inflammation. The clinical diagnosis of NSOI is ill-defined, but it is typically characterized by acute orbital signs and symptoms, including pain, proptosis, periorbital edema, chemosis, diplopia, and less commonly visual disturbance. NSOI poses a diagnostic and therapeutic challenge: The clinical presentations and histological findings are heterogeneous, and there are no specific diagnostic criteria or treatment guidelines. The etiology and pathogenesis of NSOI are poorly understood. Here we recapitulate our current clinical understanding of NSOI, with an emphasis on the most recent findings on clinical characteristics, imaging findings, and treatment outcomes. Furthermore, gene expression profiling of NSOI and its implications are presented and discussed.

Radiologic imaging shows variable accuracy in diagnosing orbital inflammatory disease and assessing its activity.

Radiologic orbital imaging provides important information in the diagnosis and management of orbital inflammation. However, the diagnostic value of orbital imaging is not well elucidated. This study aimed to investigate the diagnostic accuracy of orbital imaging to diagnose orbital inflammatory diseases and its ability to detect active inflammation. We collected 75 scans of 52 patients (49 computed tomography (CT) scans; 26 magnetic resonance (MR) imaging scans). Clinical diagnoses included thyroid eye disease (TED) (41 scans, 31 patients), non-specific orbital inflammation (NSOI) (22 scans, 14 patients), sarcoidosis (4 scans, 3 patients), IgG4-related ophthalmic disease (IgG4-ROD) (5 scans, 3 patients), and granulomatosis with polyangiitis (GPA) (3 scans, 1 patient). Two experienced neuroradiologists interpreted the scans, offered a most likely diagnosis, and assessed the activity of inflammation, blinded to clinical findings. The accuracy rate of radiological diagnosis compared to each clinical diagnosis was evaluated. Sensitivity and specificity in detecting active inflammation were analyzed for TED and NSOI. The accuracy rate of radiologic diagnosis was 80.0% for IgG4-ROD, 77.3% for NSOI, and 73.2% for TED. Orbital imaging could not diagnose sarcoidosis. Orbital CT had a sensitivity of 50.0% and a specificity of 75.0% to predict active TED using clinical assessment as the gold standard. The sensitivity/specificity of orbital MR was 83.3/16.7% for the detection of active NSOI. In conclusion, orbital imaging is accurate for the diagnosis of IgG4, NSOI, and TED. Further studies with a large number of cases are needed to confirm this finding, especially with regard to uncommon diseases. Orbital CT showed moderate sensitivity and good specificity for identifying active TED.

Ferumoxytol-Enhanced MRI Is Not Inferior to Gadolinium-Enhanced MRI in Detecting Intracranial Metastatic Disease and Metastasis Size.

OBJECTIVE. The goal of this intraindividual comparison study was to investigate whether ferumoxytol-enhanced MRI is as effective as standard-of-care gadolinium-enhanced MRI in detecting intracranial metastatic disease. MATERIALS AND METHODS. We retrospectively reviewed all patients who underwent imaging as part of two ongoing ferumoxytol-enhanced and gadolinium-enhanced MRI protocol studies to compare the number and size of enhancing metastatic lesions. Two neuroradiologists independently measured enhancing metastases on ferumoxytol-enhanced MR images and on control gadolinium-enhanced MR images. The number and size of metastases were compared on an intraindividual basis. Primary diagnoses were recorded. A linear mixed-effects model was used to compare differences in cubic root of volume between gadolinium-enhanced and ferumoxytol-enhanced MRI. A signed rank test was used to evaluate differences between reviewers. RESULTS. MR images from 19 patients with brain metastases were analyzed (seven with lung cancer, three with breast cancer, three with melanoma, two with ovarian cancer, one with colon cancer, one with renal cell carcinoma, one with carcinoid tumor, and one with uterine cancer). Reviewer 1 identified 77 masses on ferumoxytol-enhanced MRI and 72 masses on gadolinium-enhanced MRI. Reviewer 2 identified 83 masses on ferumoxytol-enhanced MRI and 78 masses on gadolinium-enhanced MRI. For reviewer 1, ferumoxytol-enhanced MRI showed a mean tumor size measuring 1.1 mm larger in each plane compared with gadolinium-enhanced MRI (p = 0.1887). For reviewer 2, ferumoxytol-enhanced MRI showed a mean tumor size measuring 1.0 mm larger in each plane (p = 0.2892). No significant differences in number of metastases or tumor sizes were observed between contrast agents or reviewers. CONCLUSION. Intracranial metastatic disease detection with ferumoxytol-enhanced MRI was not inferior to detection with gadolinium-enhanced MRI. Ferumoxytol-enhanced MRI could improve workup and monitoring of patients with brain metastases if gadolinium-enhanced MRI is contraindicated.

Stapes Surgery Outcomes in Patients With Concurrent Otosclerosis and Superior Semicircular Canal Dehiscence.

OBJECTIVE: To review outcomes of stapes surgery in patients with concurrent otosclerosis and superior semicircular canal dehiscence. STUDY DESIGN: Retrospective case series. SETTING: Tertiary referral center. PATIENTS: Patients with concurrent otosclerosis and superior canal dehiscence, confirmed by computed tomography (CT) imaging. INTERVENTION(S): Stapes surgery for conductive hearing loss. MAIN OUTCOME MEASURE(S): Postoperative air-bone gap (ABG), as well as the number of patients in whom surgery was deemed successful (postoperative ABG <10 dB HL). RESULTS: Five patients with superior canal dehiscence and concomitant otosclerosis who underwent surgical repair were identified. Mean preoperative ABG was 29.0 ±â€Š6.4 dB HL. Mean postoperative ABG was 13.0 ±â€Š13 dB HL. Three patients (60%) had a successful outcome, defined as postoperative ABG less than 10. One patient experienced unmasking of superior canal dehiscence vestibular symptoms. CONCLUSIONS: Patients with concurrent otosclerosis and superior canal dehiscence appear to have a lower likelihood of successful hearing restoration following stapes surgery. Patients should be counseled accordingly. Routine preoperative CT imaging before stapes surgery may be helpful to identify patients at risk for poor outcomes.

Combined iron oxide nanoparticle ferumoxytol and gadolinium contrast enhanced MRI define glioblastoma pseudoprogression.

BACKGROUND: Noninvasively differentiating therapy-induced pseudoprogression from recurrent disease in patients with glioblastoma is prospectively difficult due to the current lack of a biologically specific imaging metric. Ferumoxytol iron oxide nanoparticle MRI contrast characterizes innate immunity mediated neuroinflammation; therefore, we hypothesized that combined ferumoxytol and gadolinium enhanced MRI could serve as a biomarker of glioblastoma pseudoprogression. METHODS: In this institutional review board-approved, retrospective study, we analyzed ferumoxytol and gadolinium contrast enhanced T1-weighted 3T MRI in 45 patients with glioblastoma over multiple clinical timepoints. Isocitrate dehydrogenase 1 (IDH-1) mutational status was characterized by exome sequencing. Sum of products diameter measurements were calculated according to Response Assessment in Neuro-Oncology criteria from both gadolinium and ferumoxytol enhanced sequences. Enhancement mismatch was calculated as the natural log of the ferumoxytol to gadolinium sum of products diameter ratio. Analysis of variance and Student's t-test assessed differences in mismatch ratios. P-value <0.05 indicated statistical significance. RESULTS: With the development of pseudoprogression we observed a significantly elevated mismatch ratio compared with disease recurrence (P < 0.01) within IDH-1 wild type patients. Patients with IDH-1 mutation demonstrated significantly reduced mismatch ratio with the development of pseudoprogression compared with disease recurrence (P < 0.01). Receiver operator curve analysis demonstrated 100% sensitivity and specificity for the use of mismatch ratios as a diagnostic biomarker of pseudoprogression. CONCLUSION: Our study suggests that ferumoxytol to gadolinium contrast mismatch ratios are an MRI biomarker for the diagnosis of pseudoprogression in patients with glioblastoma. This may be due to the unique characterization of therapy-induced neuroinflammation.

A prospective in silico analysis of interdisciplinary and interobserver spatial variability in post-operative target delineation of high-risk oral cavity cancers: Does physician specialty matter?

BACKGROUND: The aim of this study was to determine the interdisciplinary agreement in identifying the post-operative tumor bed. METHODS: Three radiation oncologists (ROs), four surgeons, and three radiologists segmented post-operative tumor and nodal beds for three patients with oral cavity cancer. Specialty cohort composite contours were created by STAPLE algorithm implementation results for interspecialty comparison. Dice similarity coefficient and Hausdorff distance were utilized to compare spatial differentials between specialties. RESULTS: There were significant differences between disciplines in target delineation. There was unacceptable variation in Dice similarity coefficient for each observer and discipline when compared to the STAPLE contours. Within surgery and radiology disciplines, there was good consistency in volumes. ROs and radiologists have similar Dice similarity coefficient scores compared to surgeons. CONCLUSION: There were significant interdisciplinary differences in perceptions of tissue-at-risk. Better communication and explicit description of at-risk areas between disciplines is required to ensure high-risk areas are adequately targeted.

Current and potential imaging applications of ferumoxytol for magnetic resonance imaging.

Contrast-enhanced magnetic resonance imaging is a commonly used diagnostic tool. Compared with standard gadolinium-based contrast agents, ferumoxytol (Feraheme, AMAG Pharmaceuticals, Waltham, MA), used as an alternative contrast medium, is feasible in patients with impaired renal function. Other attractive imaging features of i.v. ferumoxytol include a prolonged blood pool phase and delayed intracellular uptake. With its unique pharmacologic, metabolic, and imaging properties, ferumoxytol may play a crucial role in future magnetic resonance imaging of the central nervous system, various organs outside the central nervous system, and the cardiovascular system. Preclinical and clinical studies have demonstrated the overall safety and effectiveness of this novel contrast agent, with rarely occurring anaphylactoid reactions. The purpose of this review is to describe the general and organ-specific properties of ferumoxytol, as well as the advantages and potential pitfalls associated with its use in magnetic resonance imaging. To more fully demonstrate the applications of ferumoxytol throughout the body, an imaging atlas was created and is available online as supplementary material.

Predictors of extracapsular extension in HPV-associated oropharyngeal cancer treated surgically.

OBJECTIVES: Extracapsular extension (ECE) in cervical metastatic lymph nodes remains an indication for adding chemotherapy for patients with oropharyngeal squamous cell carcinoma (OPSCC). The aim of this study is to identify specific imaging characteristics on computed tomography (CT) scan that are predictive of ECE in order to better risk stratify patients preoperatively. MATERIALS AND METHODS: A single cohort study was performed using a prospectively collected database of patients with HPV-related OPSCC who underwent transoral robotic surgery with cervical lymphadenectomy. CT scans were assessed for the presence of multiple imaging characteristics, including lymph node size, number of nodes positive, cystic appearance, and border irregularity. Univariable and multivariable analyses were performed to analyze each variable's predictability of pathologic ECE. RESULTS: 100 patients underwent TORS with cervical lymphadenectomy for OPSCC from 2010 to 2015. Ninety-one percent (21/23) of patients with 3 or more radiologically suspicious nodes were found to have pathologic ECE, which was a significantly greater proportion than patients with fewer suspicious nodes (p<0.001). CT scans with 3 or more radiologically suspicious nodes displayed a sensitivity and specificity of 55% and 94%, respectively with a positive predictive value (PPV) of 91% for ECE. Irregular borders and age were also correlated with ECE on multivariable analysis. CONCLUSION AND RELEVANCE: The presence of 3 or more radiologically suspicious lymph nodes on CT scan has a 91% PPV for any histologic evidence of ECE. The absolute number of radiographically suspicious lymph node metastases may be a useful method for risk-stratifying patients for the presence of ECE.

Misleading early blood volume changes obtained using ferumoxytol-based magnetic resonance imaging perfusion in high grade glial neoplasms treated with bevacizumab.

BACKGROUND: Neovascularization, a distinguishing trait of high-grade glioma, is a target for anti-angiogenic treatment with bevacizumab (BEV). This study sought to use ferumoxytol-based dynamic susceptibility contrast magnetic resonance imaging (MRI) to clarify perfusion and relative blood volume (rCBV) changes in glioma treated with BEV and to determine potential impact on clinical management. METHODS: 16 high grade glioma patients who received BEV following post-chemoradiation radiographic or clinical progression were included. Ferumoxytol-based MRI perfusion measurements were taken before and after BEV. Lesions were defined at each timepoint by gadolinium-based contrast agent (GBCA)-enhancing area. Lesion volume and rCBV were compared pre and post-BEV in the lesion and rCBV "hot spot" (mean of the highest rCBV in a 1.08 cm2 area in the enhancing volume), as well as hypoperfused and hyperperfused subvolumes within the GBCA-enhancing lesion. RESULTS: GBCA-enhancing lesion volumes decreased 39% (P = 0.01) after BEV. Mean rCBV in post-BEV GBCA-enhancing area did not decrease significantly (P = 0.227) but significantly decreased in the hot spot (P = 0.046). Mean and hot spot rCBV decreased (P = 0.039 and 0.007) when post-BEV rCBV was calculated over the pre-BEV GBCA-enhancing area. Hypoperfused pixel count increased from 24% to 38 (P = 0.007) and hyperperfused decreased from 39 to 28% (P = 0.017). Mean rCBV decreased in 7/16 (44%) patients from >1.75 to <1.75, the cutoff for pseudoprogression diagnosis. CONCLUSIONS: Decreased perfusion after BEV significantly alters rCBV measurements when using ferumoxytol. BEV treatment response hinders efforts to differentiate true progression from pseudoprogression using blood volume measurements in malignant glioma, potentially impacting patient diagnosis and management.

Ferumoxytol-enhanced MRI differentiation of meningioma from dural metastases: a pilot study with immunohistochemical observations.

Malignant dural neoplasms are not reliably distinguished from benign dural neoplasms with contrast-enhanced magnetic resonance imaging (MRI). MRI enhancement in central nervous system (CNS) diseases imaged with ferumoxytol has been attributed to intracellular uptake in macrophages rather than vascular leakage. We compared imaging to histopathology and immunohistochemistry in meningiomas and dural metastases having ferumoxytol-enhanced MRI (FeMRI) and gadolinium-enhanced MRI (GdMRI) in order to correlate enhancement patterns to macrophage presence and vascular state. All patients having extraaxial CNS tumors were retrospectively selected from one of two ongoing FeMRI studies. Enhancement was compared between GdMRI and FeMRI. Diagnoses were confirmed histologically and/or by characteristic imaging. Tumor and vascular histology was reviewed. Immunohistochemical staining for CD68 (a macrophage marker), Connexin-43 (Cx43) (a marker of normal gap junctions), and smooth muscle actin (SMA) as a marker of vascularity, was performed in seven study cases with available tissue. Immunohistochemistry was performed on archival material from 33 subjects outside of the current study as controls: 20 WHO grade I cases of meningioma and 13 metastatic tumors. Metastases displayed marked delayed enhancement on FeMRI, similar to GdMRI. Four patients with dural metastases and one patient with meningioma showed similar enhancement on FeMRI and GdMRI. Five meningiomas with typical enhancement on GdMRI lacked enhancement on FeMRI. Enhancement on FeMRI was better associated with decreased Cx43 expression than intralesional macrophages. These pilot data suggest that FeMRI may better differentiate metastatic disease from meningiomas than GdMRI, and that differences in tumor vasculature rather than macrophage presence could underlie differences in contrast enhancement.

Evaluation of pseudoprogression in patients with glioblastoma multiforme using dynamic magnetic resonance imaging with ferumoxytol calls RANO criteria into question.

BACKGROUND: Diagnosis of pseudoprogression in patients with glioblastoma multiforme (GBM) is limited by Response Assessment in Neuro-Oncology (RANO) criteria to 3 months after chemoradiotherapy (CRT). Frequency of pseudoprogression occurring beyond this time limit was determined. Survival comparison was made between pseudoprogression and true progression patients as determined by using perfusion magnetic resonance imaging with ferumoxytol (p-MRI-Fe). METHODS: Fifty-six patients with GBM who demonstrated conventional findings concerning for progression of disease post CRT were enrolled in institutional review board-approved MRI protocols. Dynamic susceptibility-weighted contrast-enhanced p-MRI-Fe was used to distinguish true progression from pseudoprogression using relative cerebral blood volume (rCBV) values. rCBV of 1.75 was assigned as the cutoff value. Participants were followed up using RANO criteria, and survival data were analyzed. RESULTS: Twenty-seven participants (48.2%) experienced pseudoprogression. Pseudoprogression occurred later than 3 months post CRT in 8 (29.6%) of these 27 participants (ie, 8 [14.3%] of the 56 patients meeting the inclusion criteria). Overall survival was significantly longer in participants with pseudoprogression (35.2 months) compared with those who never experienced pseudoprogression (14.3 months; P < .001). CONCLUSIONS: Pseudoprogression presented after 3 months post CRT in a considerable portion of patients with GBM, which raises doubts about the value of the 3-month time limit of the RANO criteria. Accurate rCBV measurement (eg, p-MRI-Fe) is suggested when there are radiographical concerns about progression of disease in GBM patients, regardless of any time limit. Pseudoprogression correlates with significantly better survival outcomes.

Feasibility and potential role of ferumoxytol-enhanced neuroimaging in HIV-associated neurocognitive disorder.

We assessed ferumoxytol-enhanced brain MRI to identify monocyte/macrophage accumulation in HIV-associated neurocognitive disorder (HAND). Four HIV-infected subjects with undetectable HIV RNA levels on antiretroviral therapy, HIV DNA level in CD14+ cells ≥10 copies/10(6) cells, and cognitive impairment underwent ferumoxytol-enhanced brain MRI. On post-ferumoxytol susceptibility-weighted images, all HIV-infected subjects demonstrated a diffuse "tram track" appearance in the perivascular regions of cortical and deep white matter vessels suggesting ferumoxytol uptake in monocytes/macrophages. This finding was not present in an HIV-seronegative control. While ferumoxytol may have potential as an imaging biomarker for monocyte/macrophage accumulation in patients with HAND, future study is needed.

Using iron oxide nanoparticles to diagnose CNS inflammatory diseases and PCNSL.

OBJECTIVE: The study goal was to assess the benefits and potential limitations in the use of ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles in the MRI diagnosis of CNS inflammatory diseases and primary CNS lymphoma. METHODS: Twenty patients with presumptive or known CNS lesions underwent MRI study. Eighteen patients received both gadolinium-based contrast agents (GBCAs) and 1 of 2 USPIO contrast agents (ferumoxytol and ferumoxtran-10) 24 hours apart, which allowed direct comparative analysis. The remaining 2 patients had only USPIO-enhanced MRI because of a renal contraindication to GBCA. Conventional T1- and T2-weighted MRI were acquired before and after contrast administration in all patients, and perfusion MRI for relative cerebral blood volume (rCBV) assessment was obtained in all 9 patients receiving ferumoxytol. RESULTS: USPIO-enhanced MRI showed an equal number of enhancing brain lesions in 9 of 18 patients (50%), more enhancing lesions in 2 of 18 patients (11%), and fewer enhancing lesions in 3 of 18 patients (17%) compared with GBCA-enhanced MRI. Four of 18 patients (22%) showed no MRI enhancement. Dynamic susceptibility-weighted contrast-enhanced perfusion MRI using ferumoxytol showed low rCBV (ratio <1.0) in 3 cases of demyelination or inflammation, modestly elevated rCBV in 5 cases of CNS lymphoma or lymphoproliferative disorder (range: 1.3-4.1), and no measurable disease in one case. CONCLUSIONS: This study showed that USPIO-enhanced brain MRI can be useful in the diagnosis of CNS inflammatory disorders and lymphoma, and is also useful for patients with renal compromise at risk of nephrogenic systemic fibrosis who are unable to receive GBCA.

Pseudoprogression of glioblastoma after chemo- and radiation therapy: diagnosis by using dynamic susceptibility-weighted contrast-enhanced perfusion MR imaging with ferumoxytol versus gadoteridol and correlation with survival.

PURPOSE: To compare gadoteridol and ferumoxytol for measurement of relative cerebral blood volume (rCBV) in patients with glioblastoma multiforme (GBM) who showed progressive disease at conventional magnetic resonance (MR) imaging after chemo- and radiation therapy (hereafter, chemoradiotherapy) and to correlate rCBV with survival. MATERIALS AND METHODS: Informed consent was obtained from all participants before enrollment in one of four institutional review board-approved protocols. Contrast agent leakage maps and rCBV were derived from perfusion MR imaging with gadoteridol and ferumoxytol in 19 patients with apparently progressive GBM on conventional MR images after chemoradiotherapy. Patients were classified as having high rCBV (>1.75), indicating tumor, and low rCBV (≤ 1.75), indicating pseudoprogression, for each contrast agent separately, and with or without contrast agent leakage correction for imaging with gadoteridol. Statistical analysis was performed by using Kaplan-Meier survival plots with the log-rank test and Cox proportional hazards models. RESULTS: With ferumoxytol, rCBV was low in nine (47%) patients, with median overall survival (mOS) of 591 days, and high rCBV in 10 (53%) patients, with mOS of 163 days. A hazard ratio of 0.098 (P = .004) indicated significantly improved survival. With gadoteridol, rCBV was low in 14 (74%) patients, with mOS of 474 days, and high in five (26%), with mOS of 156 days and a nonsignificant hazard ratio of 0.339 (P = .093). Five patients with mismatched high rCBV with ferumoxytol and low rCBV with gadoteridol had an mOS of 171 days. When leakage correction was applied, rCBV with gadoteridol was significantly associated with survival (hazard ratio, 0.12; P = .003). CONCLUSION: Ferumoxytol as a blood pool agent facilitates differentiation between tumor progression and pseudoprogression, appears to be a good prognostic biomarker, and unlike gadoteridol, does not require contrast agent leakage correction.

Dual contrast perfusion MRI in a single imaging session for assessment of pediatric brain tumors.

Ferumoxytol, an iron nanoparticle used as an intravascular contrast agent for perfusion magnetic resonance imaging (MRI), has never been explored in the pediatric population. The purpose of this prospective study is to characterize the vascular and permeability properties of pediatric brain tumors using two contrast agents during a single imaging session: ferumoxytol for dynamic susceptibility weighted contrast (DSC) MRI and gadoteridol for dynamic contrast-enhanced (DCE) MRI. In a single imaging session, patients received intravenous ferumoxytol for DSC MRI followed by gadoteridol for DCE MRI. Relative cerebral blood volume (rCBV), relative cerebral blood flow (rCBF), transfer coefficient (K(trans)), and extravascular extracellular space volume fraction (v(e)) of the brain lesions were calculated. Patients underwent serial imaging sessions over the course of 2 years. Of the 7 patients enrolled thus far, none has experienced an adverse event. Two patients with medulloblastoma were enrolled preoperatively. In the first, rCBV(max), rCBF, K(trans) max, and v(e) max values were 3.74, 3.12, 0.47 min (-1), and 0.08, respectively, while in the second patient, rCBV(max), rCBF, K(trans) max, and v(e) max values were 4.72, 3.47, 0.60 min(-1), and 0.05, respectively. Four patients were enrolled after new gadolinium enhancement was noted in the tumor resection cavity. In 80 % of these lesions, rCBV was <1 suggestive of pseudoprogression secondary to radiochemotherapy. These preliminary results demonstrate that use of ferumoxytol and gadoteridol contrast agents during a single imaging session is feasible, safe, and appears useful for assessing tumor perfusion and permeability characteristics in children.

Characteristic imaging findings in lymphoceles of the head and neck.

OBJECTIVE: Lymphoceles are benign neck cysts that are important to differentiate from congenital, infectious, and malignant cystic neck masses because they require unique surgical treatment and follow-up. We reviewed a series of surgically proven lymphoceles to delineate the radiologic characteristics of lymphoceles that differentiate them from other cystic neck masses. MATERIALS AND METHODS: A search of radiology report impressions for the terms "lymphocele" and "lymphatic cyst" was performed on all neck CT, MRI, and sclerotherapy studies from January 2003 to December 2009 at our institution. Clinical and pathology records were searched for the same terms to identify additional cases. Medical records confirmed diagnosis. Study images were reviewed on PACS to assess cyst location and imaging characteristics. RESULTS: There were nine patients (six women and three men; age range, 22-85 years; mean age, 50.1 years) with 12 pathologically proven lymphoceles on six contrast-enhanced CT and three contrast-enhanced MRI examinations. Lymphoceles were located in the posterior cervical space in 12 of 12 and supraclavicular in 10 of 12 cases. Lymphoceles were unilocular nonseptated cysts in 12 of 12, fluid density or signal in 11 of 12, nonenhancing in 12 of 12, and lacked a cyst wall in eight of 12. CONCLUSION: Lymphoceles are rare unilocular cystic neck masses that may mimic other congenital, infectious, and malignant neck cysts. When enhanced CT or MRI shows a unilocular, nonseptated, fluid density or intensity, and nonenhancing supraclavicular cyst in the posterior cervical space, lymphocele is an important part of the differential diagnosis. Atypical features warrant fine-needle aspiration or follow-up for confirmation.