Prospective Cohort Study of Nephrogenic Systemic Fibrosis in Patients With Stage 3-5 Chronic Kidney Disease Undergoing MRI With Injected Gadobenate Dimeglumine or Gadoteridol.

OBJECTIVE: The purpose of this study was to determine the incidence of nephrogenic systemic fibrosis (NSF) in patients with chronic kidney disease (CKD) and moderate-to-severe impairment of kidney function who had not previously been exposed to gadolinium-based contrast agents (GBCAs) or referred to undergo contrast-enhanced MRI with gadobenate dimeglumine or gadoteridol. SUBJECTS AND METHODS: Two multicenter prospective cohort studies evaluated the incidence of unconfounded NSF in patients with stage 3 CKD (estimated glomerular filtration rate [eGFR] in cohort 1, 30-59 mL/min/1.73 m(2)) or stage 4 or 5 CKD (eGFR in cohort 2, < 30 mL/min/1.73 m(2)) after injection of gadobenate dimeglumine (study A) or gadoteridol (study B). A third study (study C) determined the incidence of NSF in patients with stage 4 or 5 CKD who had not received a GBCA in the 10 years before enrollment. Monitoring for signs and symptoms suggestive of NSF was performed via telephone at 1, 3, 6, and 18 months, with clinic visits occurring at 1 and 2 years. RESULTS: For studies A and B, the populations evaluated for NSF comprised 363 and 171 patients, respectively, with 318 and 159 patients in cohort 1 of each study, respectively, and with 45 and 12 patients in cohort 2, respectively. No signs or symptoms of NSF were reported or detected during the 2 years of patient monitoring. Likewise, no cases of NSF were reported for any of the 405 subjects enrolled in study C. CONCLUSION: To our knowledge, and consistent with reports in the literature, no association of gadobenate dimeglumine or gadoteridol with unconfounded cases of NSF has yet been established. Study data confirm that both gadoteridol and gadobenate dimeglumine properly belong to the class of GBCAs considered to be associated with the lowest risk of NSF.

Imaging evaluation of CSF shunts.

OBJECTIVE: The objective of this article is to describe an approach to imaging CSF shunts. Topics reviewed include the components and imaging appearances of the most common types of shunts and the utility of different imaging modalities for the evaluation of shunt failure. Complications discussed include mechanical failure, infection, ventricular loculation, overdrainage, and unique complications related to each shunt type. CONCLUSION: This article reviews the imaging features of common CSF shunts and related complications with which radiologists should be familiar.

A two-tiered approach to MRI for hearing loss: incremental cost of a comprehensive MRI over high-resolution T2-weighted imaging.

OBJECTIVE: The objective of our study was to compare the cost-effectiveness of two approaches to using MRI for the evaluation of patients with hearing loss. MATERIALS AND METHODS: We developed a decision tree to compare the cost-effectiveness of conventional MRI with that of a proposed two-tiered model in which an initial 3D T2-weighted imaging examination was used to determine the need for comprehensive MR scanning. Three radiologists independently and blindly reviewed the 3D T2-weighted images acquired as part of the comprehensive MR examinations of 256 patients with hearing loss to assess the diagnostic efficacy of the two-tiered approach. Costs were defined in terms of both the scanner utilization time for the imaging facility and the dollar amount for payers. Effectiveness was defined in terms of the ability to correctly detect the presence or absence of disease. RESULTS: The conventional approach was less cost-effective, with a baseline incremental cost-effectiveness ratio (ICER) of 27,299 minutes of scanner utilization per unit increase in effectiveness. Assuming a 50% reduction in the reimbursement of the technical component from the current level by the Centers for Medicare & Medicaid Services, this result reflected an ICER of $258,664 per unit increase in effectiveness. The results of a sensitivity analysis showed the robustness of the cost-effectiveness of the two-tiered imaging approach in a variety of scenarios that reflect differences in scanning practices and possible differences in recall rates. The conventional imaging approach was absolutely dominated by the two-tiered approach in the scenarios created to reflect the expected range of prevalence of disease. CONCLUSION: A two-tiered approach to MRI provides a more cost-effective alternative to the current approach of using a comprehensive MRI examination without and with contrast material to evaluate patients with hearing loss.

Automated classification of radiology reports to facilitate retrospective study in radiology.

Retrospective research is an import tool in radiology. Identifying imaging examinations appropriate for a given research question from the unstructured radiology reports is extremely useful, but labor-intensive. Using the machine learning text-mining methods implemented in LingPipe [1], we evaluated the performance of the dynamic language model (DLM) and the Naïve Bayesian (NB) classifiers in classifying radiology reports to facilitate identification of radiological examinations for research projects. The training dataset consisted of 14,325 sentences from 11,432 radiology reports randomly selected from a database of 5,104,594 reports in all disciplines of radiology. The training sentences were categorized manually into six categories (Positive, Differential, Post Treatment, Negative, Normal, and History). A 10-fold cross-validation [2] was used to evaluate the performance of the models, which were tested in classification of radiology reports for cases of sellar or suprasellar masses and colloid cysts. The average accuracies for the DLM and NB classifiers were 88.5% with 95% confidence interval (CI) of 1.9% and 85.9% with 95% CI of 2.0%, respectively. The DLM performed slightly better and was used to classify 1,397 radiology reports containing the keywords "sellar or suprasellar mass", or "colloid cyst". The DLM model produced an accuracy of 88.2% with 95% CI of 2.1% for 959 reports that contain "sellar or suprasellar mass" and an accuracy of 86.3% with 95% CI of 2.5% for 437 reports of "colloid cyst". We conclude that automated classification of radiology reports using machine learning techniques can effectively facilitate the identification of cases suitable for retrospective research.

Two-tiered approach to MRI for headache: a cost-effective way to use an expensive technology.

OBJECTIVE: The purpose of this study was to compare the diagnostic efficacy and cost implications of a proposed two-tiered approach to MRI in patients with headache. MATERIALS AND METHODS: We identified 245 consecutive patients with headache using MRI studies performed at a tertiary care facility between October 2009 and July 2011. Three radiologists prospectively used FLAIR sequences from these MR studies to diagnose underlying abnormality or to identify the need for a comprehensive MRI study. We compared the diagnostic efficacy and the cost implications of such a two-tiered approach with those of conventional MRI from the perspectives of the payer, the patient, and the imaging facility. RESULTS: The sensitivity and specificity for two-tiered (83.3% and 100%, respectively) and conventional (91% and 97.8%, respectively) MRI approaches were not significantly different. Assuming a 50% reduction in the payment for the initial limited MRI performed as a first step of the two-tiered approach, this approach would have resulted in 44.8% savings to the payer. A substantial reduction in the scanner utilization time from 4168 minutes to 1249 minutes for the two-tiered approach would have enabled increased throughput at the imaging facility. Although 27 (11%) patients would have been recalled for a comprehensive MRI study in the two-tiered approach, the average time spent in the scanner by each patient would have been less for the two-tiered approach (5.1 minutes vs 17.0 minutes). CONCLUSION: A two-tiered approach to MRI can serve as a viable cost-effective alternative to the conventional approach.

Neuroimaging of Adult Lacrimal Drainage System.

The lacrimal drainage system (LDS) pathology is frequently encountered in the ophthalmology setting but is rarely discussed in the radiology literature. This is even truer for adult LDS lesions despite increase utilization of computed tomography and magnetic resonance in imaging for diagnosis of LDS pathology. The purpose of this image rich review is to highlight common adult LDS pathologies and introduce the radiologist to rare disease entities affecting this pathology rich anatomical region with emphasis on imaging findings, clinical presentation, and differential generation.

Osseous metaplasia late in the course of nephrogenic systemic fibrosis.

Osseous metaplasia has recently been described in several cases of nephrogenic systemic fibrosis, sometimes in association with unusual clinical features such as painful hyperkeratotic spicules, palpable bony masses, and disease regression. Some authors have suggested that it may mainly occur late in the disease course or even be a marker for involuting nephrogenic systemic fibrosis. Here, we present a 27-year-old woman with a 7-year history of nephrogenic systemic fibrosis, who developed cutaneous osseous metaplasia.

Enlarged vestibular aqueduct in pediatric sensorineural hearing loss.

OBJECTIVE: Comparison of the Cincinnati criteria (midpoint >0.9 mm or operculum >1.9 mm) to the Valvassori criterion (midpoint > or =1.5 mm) for enlarged vestibular aqueduct (EVA) in pediatric cochlear implant patients. STUDY DESIGN: Cohort study. SUBJECTS: One hundred thirty pediatric cochlear implant recipients. METHODS: We reviewed temporal bone CT scans to measure the vestibular aqueduct midpoint and opercular width. RESULTS: The Cincinnati criteria identified 44 percent of patients with EVA versus 16 percent with the Valvassori criterion (P < 0.01). Of those with EVA, 45 percent were unilateral and 55 percent were bilateral using Cincinnati criteria; 64 percent were unilateral and 36 percent bilateral using Valvassori criterion (P < 0.01). The Cincinnati criteria diagnosed 70 ears with EVA classified as normal using the Valvassori criterion (P < 0.01); 59 lacked another medical explanation for their hearing loss. CONCLUSION: The Cincinnati criteria identified a large percentage of pediatric cochlear implant patients with EVA who might otherwise have no known etiology for their deafness.

Evaluation of intraaxial enhancing brain tumors on magnetic resonance imaging: intraindividual crossover comparison of gadobenate dimeglumine and gadopentetate dimeglumine for visualization and assessment, and implications for surgical intervention.

OBJECT: The goal in this article was to compare 0.1 mmol/kg doses of gadobenate dimeglumine (Gd-BOPTA) and gadopentetate dimeglumine, also known as gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA), for enhanced magnetic resonance (MR) imaging of intraaxial brain tumors. METHODS: Eighty-four patients with either intraaxial glioma (47 patients) or metastasis (37 patients) underwent two MR imaging examinations at 1.5 tesla, one with Gd-BOPTA as the contrast agent and the other with Gd-DTPA. The interval between fully randomized contrast medium administrations was 2 to 7 days. The T1-weighted spin echo and T2-weighted fast spin echo images were acquired before administration of contrast agents and T1-weighted spin echo images were obtained after the agents were administered. Acquisition parameters and postinjection acquisition times were identical for the two examinations in each patient. Three experienced readers working in a fully blinded fashion independently evaluated all images for degree and quality of available information (lesion contrast enhancement, lesion border delineation, definition of disease extent, visualization of the lesion's internal structures, global diagnostic preference) and quantitative enhancement (that is, the extent of lesion enhancement after contrast agent administration compared with that seen before its administration [hereafter referred to as percent enhancement], lesion/brain ratio, and contrast/noise ratio). Differences were tested with the Wilcoxon signed-rank test. Reader agreement was assessed using kappa statistics. Significantly better diagnostic information/imaging performance (p < 0.0001, all readers) was obtained with Gd-BOPTA for all visualization end points. Global preference for images obtained with Gd-BOPTA was expressed for 42 (50%), 52 (61.9%), and 56 (66.7%) of 84 patients (readers 1, 2, and 3, respectively) compared with images obtained with Gd-DTPA contrast in four (4.8%), six (7.1%), and three (3.6%) of 84 patients. Similar differences were noted for all other visualization end points. Significantly greater quantitative contrast enhancement (p < 0.04) was noted after administration of Gd-BOPTA. Reader agreement was good (kappa > 0.4). CONCLUSIONS: Lesion visualization, delineation, definition, and contrast enhancement are significantly better after administration of 0.1 mmol/kg Gd-BOPTA, potentially allowing better surgical planning and follow up and improved disease management.

Natural history of colloid cysts of the third ventricle.

OBJECTIVE Colloid cysts are rare, histologically benign lesions that may result in obstructive hydrocephalus and death. Understanding the natural history of colloid cysts has been challenging given their low incidence and the small number of cases in most reported series. This has complicated efforts to establish reliable prognostic factors and surgical indications, particularly for asymptomatic patients with incidental lesions. Risk factors for obstructive hydrocephalus in the setting of colloid cysts remain poorly defined, and there are no grading scales on which to develop standard management strategies. METHODS The authors performed a single-center retrospective review of all cases of colloid cysts of the third ventricle treated over nearly 2 decades at Washington University. Univariate analysis was used to identify clinical, imaging, and anatomical factors associated with 2 outcome variables: symptomatic clinical status and presentation with obstructive hydrocephalus. A risk-prediction model was defined using bootstrapped logistic regression. Predictive factors were then combined into a simple 5-point clinical scale referred to as the Colloid Cyst Risk Score (CCRS), and this was evaluated with receiver-operator characteristics. RESULTS The study included 163 colloid cysts, more than half of which were discovered incidentally. More than half of the incidental cysts (58%) were followed with surveillance neuroimaging (mean follow-up 5.1 years). Five patients with incidental cysts (8.8%) progressed and underwent resection. No patient with an incidental, asymptomatic colloid cyst experienced acute obstructive hydrocephalus or sudden neurological deterioration in the absence of antecedent trauma. Nearly half (46.2%) of symptomatic patients presented with hydrocephalus. Eight patients (12.3%) presented acutely, and there were 2 deaths due to obstructive hydrocephalus and herniation. The authors identified several factors that were strongly correlated with the 2 outcome variables and defined third ventricle risk zones where colloid cysts can cause obstructive hydrocephalus. No patient with a lesion outside these risk zones presented with obstructive hydrocephalus. The CCRS had significant predictive capacity for symptomatic clinical status (area under the curve [AUC] 0.917) and obstructive hydrocephalus (AUC 0.845). A CCRS ≥ 4 was significantly associated with obstructive hydrocephalus (p < 0.0001, RR 19.4). CONCLUSIONS Patients with incidentally discovered colloid cysts can experience both lesion enlargement and symptom progression or less commonly, contraction and symptom regression. Incidental lesions rarely cause acute obstructive hydrocephalus or sudden neurological deterioration in the absence of antecedent trauma. Nearly one-half of patients with symptomatic colloid cysts present with obstructive hydrocephalus, which has an associated 3.1% risk of death. The CCRS is a simple 5-point clinical tool that can be used to identify symptomatic lesions and stratify the risk of obstructive hydrocephalus. External validation of the CCRS will be necessary before objective surgical indications can be established. Surgical intervention should be considered for all patients with CCRS ≥ 4, as they represent the high-risk subgroup.

Primary hypothyroidism in a 12-year-old girl with a suprasellar pituitary mass: rapid regression after thyroid replacement therapy: case report.

The authors report on a 12-year-old girl with a suprasellar mass and primary hypothyroidism in whom the lesion promptly regressed following initiation of thyroid replacement therapy. Based on this experience, it is suggested that secondary pituitary hyperplasia be included in the differential diagnostic considerations of a suprasellar lesion in a child and that resolution of the hyperplasia may occur in a matter of weeks rather than months as previously reported.

ACR Appropriateness Criteria Dementia and Movement Disorders.

Neurodegenerative disease, including dementia, extrapyramidal degeneration, and motor system degeneration, is a growing public health concern and is quickly becoming one of the top health care priorities of developed nations. The primary function of anatomic neuroimaging studies in evaluating patients with dementia or movement disorders is to rule out structural causes that may be reversible. Lack of sensitivity and specificity of many neuroimaging techniques applied to a variety of neurodegenerative disorders has limited the role of neuroimaging in differentiating types of neurodegenerative disorders encountered in everyday practice. Nevertheless, neuroimaging is a valuable research tool and has provided insight into the structure and function of the brain in patients with neurodegenerative disorders. Advanced imaging techniques, such as functional neuroimaging with MRI and MR spectroscopy, hold exciting investigative potential for better understanding of neurodegenerative disorders, but they are not considered routine clinical practice at this time. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 3 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

Determination and delineation of nodal target volumes for head-and-neck cancer based on patterns of failure in patients receiving definitive and postoperative IMRT.

PURPOSE: We present the guidelines for target volume determination and delineation of head-and-neck lymph nodes based on the analysis of the patterns of nodal failure in patients treated with intensity-modulated radiotherapy (IMRT). METHODS AND MATERIALS: Data pertaining to the natural course of nodal metastasis for each head-and-neck cancer subsite were reviewed. A system was established to provide guidance for nodal target volume determination and delineation. Following these guidelines, 126 patients (52 definitive, 74 postoperative) were treated between February 1997 and December 2000 with IMRT for head-and-neck cancer. The median follow-up was 26 months (range 12-55), and the patterns of nodal failure were analyzed. RESULTS: These guidelines define the nodal target volume based on the location of the primary tumor and the probability of microscopic metastasis to the ipsilateral and contralateral (Level I-V) nodal regions. Following these guidelines, persistent or recurrent nodal disease was found in 6 (12%) of 52 patients receiving definitive IMRT, and 7 (9%) of 74 patients receiving postoperative IMRT had failure in the nodal region. CONCLUSION: On the basis of our clinical experience in implementing inverse-planning IMRT for head-and-neck cancer, we present guidelines using a simplified, but clinically relevant, method for nodal target volume determination and delineation. The intention was to provide a foundation that enables different institutions to exchange clinical experiences in head-and-neck IMRT. These guidelines will be subject to future refinement when the clinical experience in head-and-neck IMRT advances.

West Nile virus: case report with MR imaging findings.

We report a case of serologically proved West Nile virus encephalitis. Striking bilateral hyperintensities were noted in the basal ganglia and thalami on T2-weighted and fluid-attenuated inversion recovery MR images, similar to previous accounts of the imaging findings in cases of Japanese encephalitis. Recognition of the MR imaging appearance of this entity is important because of the expanding epidemic.

Rhinocerebral mucormycosis in the era of lipid-based amphotericin B: case report and literature review.

Rhinocerebral mucormycosis (RCM) is an invasive fungal infection that necessitates, in most cases, aggressive surgical debridement and high cumulative, often nephrotoxic doses of amphotericin B. A 50-year-old woman with RCM was treated successfully with amphotericin B lipid complex as primary therapy. The patient previously had displayed progressive intracranial involvement and rising serum creatinine levels while receiving the conventional (nonlipid) form of amphotericin B. A literature review identified only a few cases where systemic antifungal therapy was administered, with minimal or no surgery. Our case further supports that amphotericin B lipid complex can be used as primary therapy in selected patients with RCM, without the need for surgical exenteration.

Cochlear implantation in children with CHARGE association.

OBJECTIVE: To explore the anomalies of the temporal bone found on radiologic examination, technical challenges in cochlear implantation, and audiologic benefit derived from cochlear implantation in a series of children with CHARGE association. DESIGN: Case series report. SETTING: Tertiary referral children's hospital pediatric cochlear implant program. PATIENTS: Six children with CHARGE association and sensorineural hearing loss. INTERVENTION: All patients were evaluated and followed up by the cochlear implant team. Cochlear implantation was attempted in all 6 children. MAIN OUTCOME MEASURES: Computed tomographic scans and cochlear implantation operative records were reviewed, and their findings were correlated. Audiometric and speech perception data before and after cochlear implantation were compared. RESULTS: Five children with CHARGE association received implants. A sixth child did not because of an aberrant course to the facial nerve. The 5 children receiving implants obtained varying degrees of measurable benefit from their implants. All 6 children had temporal bone abnormalities seen on their computed tomographic scans and documented at the time of surgery. CONCLUSIONS: Variations in the temporal bone anatomy of patients with CHARGE association can lead to increased technical challenges and risk to the facial nerve during cochlear implantation. Individual outcomes after implantation may vary; our patients receiving implants obtained benefit. Parents should be counseled thoroughly and have appropriate expectations before proceeding with implantation.

Imaging the treated oral cavity and oropharynx.

Cross-sectional imaging has become essential in the evaluation of the treated oral cavity and oropharynx. The purpose of this paper is to review the imaging guidelines for the evaluation of this region and to detail the typical changes encountered on imaging following surgical and radiation treatment for cancer.

Diffusion-weighted MR imaging in the preoperative assessment of brain abscesses.

BACKGROUND: Diffusion-weighted MR imaging (DWI) has recently shown promise in differentiating ring-enhancing lesions such as brain abscess and malignant neoplasm. The ability of DWI to strongly suggest brain abscess enables a neurosurgeon to alter stereotactic planning to optimize diagnosis. We report our experience with DWI in 5 patients with lesions on MR imaging and review the literature to assess the usefulness of this technique in the preoperative evaluation of cerebral abscess. METHODS: The MR images of 5 patients presenting with ring-enhancing lesions that ultimately proved to be brain abscesses were retrospectively reviewed. In addition to standard MR sequences, trace DWI and apparent diffusion coefficient (ADC) calculations were performed on all patients. Additionally, 15 recently published articles or references in press concerning DWI in cerebral abscesses were reviewed. RESULTS: All lesions were markedly hyperintense on DWI and had diminished ADC. Thirty-eight of 39 previously reported abscesses were hyperintense on DWI with reduced ADC. Of 165 nonpyogenic lesions with DWI findings, 87 were hypointense or isointense, 78 lesions had variable hyperintensities, and few manifested the degree of hyperintensity observed with abscesses. Most of these included chordomas and epidermoids, which are not likely to be confused with abscesses. CONCLUSIONS: Restricted water diffusion, as indicated by hyperintensity on DWI and low ADC, in ring-enhancing lesions assists in differentiating brain abscess from necrotic tumor. This information facilitates stereotactic surgical planning: abscesses should be preferentially centrally aspirated, whereas necrotic brain tumors should have diagnostic tissue biopsied from cavity walls. Although not definitive for brain abscess, restricted water diffusion is an important MR imaging sign and is useful in neurosurgical treatment strategies for ring-enhancing lesions.

ACR appropriateness criteria management of vertebral compression fractures.

This is an updated review of management of vertebral compression fracture for both benign osteoporotic and malignant causes. Vertebral compression fracture radiologic imaging evaluation is discussed. A literature review is provided of current indications for vertebral augmentation with percutaneous vertebroplasty and kyphoplasty as well as medical management. Limitations and potential benefits of these procedures are discussed. Variant tables describing various clinical situations are also provided to assist in determining appropriate use of these treatments for patient care. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 3 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to formulate recommendations for imaging or treatment.

ACR Appropriateness Criteria® pre-irradiation evaluation and management of brain metastases.

Pretreatment evaluation is performed to determine the number, location, and size of the brain metastases and magnetic resonance imaging (MRI) is the recommended imaging technique, particularly in patients being considered for surgery or stereotactic radiosurgery. A contiguous thin-cut volumetric MRI with gadolinium with newer gadolinium-based agents can improve detection of small brain metastases. A systemic workup and medical evaluation are important, given that subsequent treatment for the brain metastases will also depend on the extent of the extracranial disease and on the age and performance status of the patient. Patients with hydrocephalus or impending brain herniation should be started on high doses of corticosteroids and evaluated for possible neurosurgical intervention. Patients with moderate symptoms should receive approximately 4-8 mg/d of dexamethasone in divided doses. The routine use of corticosteroids in patients without neurologic symptoms is not necessary. There is no proven benefit of anticonvulsants in patient without seizures. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 3 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances where evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.