Brent Griffith

Screening Cervical Spine CT in a Level I Trauma Center: Overutilization?

OBJECTIVE The objective of our study was to analyze the use of screening cervical spine CT performed after trauma and establish the opportunity of potentially avoidable studies when evidence-based clinical criteria are applied before imaging. MATERIALS AND METHODS All cervical spine CT examinations performed in the emergency department of a level 1 trauma center between January and December 2008 on adult patients with trauma were analyzed; 1589 studies were evaluated. Radiology reports and clinical data were reviewed for the presence of fracture or ligamentous injury and for the mode of injury. We also looked for documentation of clinical criteria used to perform the CT study. In particular, we looked for mention of posterior midline cervical tenderness, focal neurologic deficit, level of alertness, evidence of intoxication, and clinically apparent distracting injury. These five criteria were established by the National Emergency X-Radiography Utilization Study (NEXUS) to identify patients with a low probability of cervical spine injury who consequently needed no cervical spine imaging. RESULTS Of the 1589 studies reviewed, 41 (2.6%) were positive for an acute cervical spine injury and 1524 (95.9%) were negative. The remaining 24 studies (1.5%) were indeterminate on the initial CT examination but subsequent imaging and clinical follow-up failed to show acute injury. Of the 1524 examinations with no acute injury, 364 (23.9%) had no documentation of any of the five NEXUS low-risk criteria. CONCLUSION The strict application of the NEXUS low-risk criteria could potentially reduce the number of screening cervical spine CT examinations in the setting of trauma in more than 20% of cases, thereby avoiding a significant amount of unnecessary radiation and significant cost.

Texture Feature Ratios from Relative CBV Maps of Perfusion MRI Are Associated with Patient Survival in Glioblastoma

BACKGROUND AND PURPOSE: Texture analysis has been applied to medical images to assist in tumor tissue classification and characterization. In this study, we obtained textural features from parametric (relative CBV) maps of dynamic susceptibility contrast-enhanced MR images in glioblastoma and assessed their relationship with patient survival. MATERIALS AND METHODS: MR perfusion data of 24 patients with glioblastoma from The Cancer Genome Atlas were analyzed in this study. One- and 2D texture feature ratios and kinetic textural features based on relative CBV values in the contrast-enhancing and nonenhancing lesions of the tumor were obtained. Receiver operating characteristic, Kaplan-Meier, and multivariate Cox proportional hazards regression analyses were used to assess the relationship between texture feature ratios and overall survival. RESULTS: Several feature ratios are capable of stratifying survival in a statistically significant manner. These feature ratios correspond to homogeneity (P = .008, based on the log-rank test), angular second moment (P = .003), inverse difference moment (P = .013), and entropy (P = .008). Multivariate Cox proportional hazards regression analysis showed that homogeneity, angular second moment, inverse difference moment, and entropy from the contrast-enhancing lesion were significantly associated with overall survival. For the nonenhancing lesion, skewness and variance ratios of relative CBV texture were associated with overall survival in a statistically significant manner. For the kinetic texture analysis, the Haralick correlation feature showed a P value close to .05. CONCLUSIONS: Our study revealed that texture feature ratios from contrast-enhancing and nonenhancing lesions and kinetic texture analysis obtained from perfusion parametric maps provide useful information for predicting survival in patients with glioblastoma.

Perfusion Imaging in Neuro-Oncology: Basic Techniques and Clinical Applications

Perfusion imaging is a method for assessing the flow of blood occurring at the tissue level and can be accomplished by both CT and MR perfusion techniques. The use of perfusion imaging has increased substantially in the past decade, particularly in neuro-oncologic imaging, where it is has been used for brain tumor grading and directing biopsies or targeted therapy, as well as for the evaluation of treatment response and disease progression. This article discusses the basic principles and techniques of perfusion imaging, as well as its applications in neuro-oncology.

T2-FLAIR Mismatch, an Imaging Biomarker for IDH and 1p/19q Status in Lower Grade Gliomas: A TCGA/TCIA Project

Purpose: Lower-grade gliomas (WHO grade II/III) have been classified into clinically relevant molecular subtypes based on IDH and 1p/19q mutation status. The purpose was to investigate whether T2/FLAIR MRI features could distinguish between lower-grade glioma molecular subtypes. Experimental Design: MRI scans from the TCGA/TCIA lower grade glioma database (n = 125) were evaluated by two independent neuroradiologists to assess (i) presence/absence of homogenous signal on T2WI; (ii) presence/absence of “T2–FLAIR mismatch” sign; (iii) sharp or indistinct lesion margins; and (iv) presence/absence of peritumoral edema. Metrics with moderate–substantial agreement underwent consensus review and were correlated with glioma molecular subtypes. Somatic mutation, DNA copy number, DNA methylation, gene expression, and protein array data from the TCGA lower-grade glioma database were analyzed for molecular–radiographic associations. A separate institutional cohort (n = 82) was analyzed to validate the T2–FLAIR mismatch sign. Results: Among TCGA/TCIA cases, interreader agreement was calculated for lesion homogeneity [κ = 0.234 (0.111–0.358)], T2–FLAIR mismatch sign [κ = 0.728 (0.538–0.918)], lesion margins [κ = 0.292 (0.135–0.449)], and peritumoral edema [κ = 0.173 (0.096–0.250)]. All 15 cases that were positive for the T2–FLAIR mismatch sign were IDH-mutant, 1p/19q non-codeleted tumors (P < 0.0001; PPV = 100%, NPV = 54%). Analysis of the validation cohort demonstrated substantial interreader agreement for the T2–FLAIR mismatch sign [κ = 0.747 (0.536–0.958)]; all 10 cases positive for the T2–FLAIR mismatch sign were IDH-mutant, 1p/19q non-codeleted tumors (P < 0.00001; PPV = 100%, NPV = 76%). Conclusions: Among lower-grade gliomas, T2–FLAIR mismatch sign represents a highly specific imaging biomarker for the IDH-mutant, 1p/19q non-codeleted molecular subtype. Clin Cancer Res; 23(20); 6078–85. ©2017 AACR.

Autoimmune Encephalitis: Pathophysiology and Imaging Review of an Overlooked Diagnosis

SUMMARY: Autoimmune encephalitis is a relatively new category of immune-mediated disease involving the central nervous system that demonstrates a widely variable spectrum of clinical presentations, ranging from the relatively mild or insidious onset of cognitive impairment to more complex forms of encephalopathy with refractory seizure. Due to its diverse clinical features, which can mimic a variety of other pathologic processes, autoimmune encephalitis presents a diagnostic challenge to clinicians. Imaging findings in patients with these disorders can also be quite variable, but recognizing characteristic findings within limbic structures suggestive of autoimmune encephalitis can be a key step in alerting clinicians to the potential diagnosis and ensuring a prompt and appropriate clinical work-up. In this article, we review antibody-mediated encephalitis and its various subtypes with a specific emphasis on the role of neuroimaging in the diagnostic work-up.

Morphometrics as a predictor of perioperative morbidity after lumbar spine surgery

OBJECT Improved objective assessments of perioperative risk after spine surgery are necessary to decrease postoperative morbidity and mortality rates. Morphometric analysis has proven utility in predicting postoperative morbidity and mortality in surgical disciplines. The aim of the present study was to evaluate whether morphometrics can be applied to the cases of patients undergoing lumbar spine surgery. METHODS The authors performed a retrospective review of the perioperative course of 395 patients who underwent lumbar surgery at their institution from 2013 to 2014. Preoperative risk factors such as age, diabetes, smoking, coronary artery disease, and body mass index (BMI) were recorded. Preoperative MRI was used to measure the psoas muscle area at the L-4 vertebra and paraspinal muscle area at the T-12 vertebra. Primary outcomes included unplanned return to the operating room, 30- and 90-day readmissions, surgical site infection, wound dehiscence, new neurological deficit, deep vein thrombosis, pulmonary embolism, myocardial infarction, urinary tract infection, urinary retention, hospital-acquired pneumonia, stroke, and prolonged stay in the intensive care unit. RESULTS The overall rate of adverse events was 30%, the most common event being urinary retention (12%). Greater age (p = 0.015) and tobacco usage (p = 0.026) were both significantly associated with complications for all patients, while diabetes, coronary artery disease, and high BMI were not. No surgery-related characteristics were associated with postoperative morbidity, including whether surgery required instrumentation, whether it was a revision, or the number of vertebral levels treated. Using multivariate regression analysis, male and female patients with the lowest psoas tertile had an OR of 1.70 (95% CI 1.04-2.79, p = 0.035) for having postoperative complications. Male patients in the lowest psoas tertile had an OR of 2.42 (95% CI 1.17-5.01, p = 0.016) for having a postoperative complication. The paraspinal muscle groups did not provide any significant data for postoperative morbidity, even after multivariate analysis. CONCLUSIONS The morphometric measurement of psoas muscle size may be a sensitive predictive tool compared with other risk factors for perioperative morbidity in male patients undergoing lumbar surgery.

Prognostic Vascular Imaging Biomarkers in High-Grade Gliomas. Tumor Permeability as an Adjunct to Blood Volume Estimates.

RATIONALE AND OBJECTIVES Despite recent advances in the treatment of high-grade gliomas, overall survival (OS) remains poor, which underlines the importance of searching for and determining prognostic imaging biomarkers. The purpose of our retrospective study was to correlate patient survival with relative cerebral blood volume (rCBV) and permeability surface area-product (PS) measured using perfusion computed tomography (PCT) in patients with high-grade gliomas. METHODS This study was composed of 54 patients with high-grade gliomas (World Health Organization [WHO] grade III, n = 14; WHO grade IV, n = 40) who underwent pretreatment PCT. Kaplan-Meier survival estimates were computed to describe OS for patients with high-versus-low PCT parameters, as well as grade III and IV gliomas. RESULTS Differences in OS between high and low rCBV, PS, and rCBV + PS were significant (P < .001) for all high-grade gliomas. After adjustment for WHO grade, rCBV (P = .041) and rCBV + PS (P = .013) estimates remained significant, whereas PS estimates were not (P = .214). PS estimates showed a statistically significant difference for OS in the grade III glioma group (P = .011), whereas for grade IV gliomas, rCBV estimates were statistically significant (P = .019). rCBV + PS was statistically significant for OS in both grade III (P = .001) and grade IV (P = .004) glioma groups. CONCLUSIONS Blood volume and permeability estimates measured using PCT can help predict survival in patients with high-grade gliomas. Patients with high PCT parameters showed worse OS compared to the patients with low PCT. Both rCBV and rCBV + PS remained statistically significant even after adjustment for WHO grade, suggesting these may be better predictors of OS than histological grade.

Screening cervical spine CT in the emergency department, phase 3: Increasing effectiveness of imaging

PURPOSE The aim of this study was to determine the effect of a clinical education initiative on the appropriate utilization of screening cervical spine CT in the emergency department. The purpose was to assess if clinical education can produce stricter adherence to the ACR Appropriateness Criteria and improve the utilization of screening CT examinations in the emergency department. METHODS Institutional review board approval was obtained for this HIPAA-compliant study. All adult patients presenting to a level 1 trauma center with blunt trauma prompting screening cervical spine CT were eligible. For each study, the requesting clinician completed a survey selecting all clinical indications. CT examinations were evaluated by a board-certified radiologist blinded to survey data. Results were compared with retrospective and prospective studies performed before the institution of the education initiative. RESULTS Of the 388 cervical spine CT examinations performed, 12 (3.1%) were positive for acute cervical spine injury, compared to only 1.0% before the clinical education program (phase 2). Of the 376 examinations without injury, 13% met all 5 National Emergency X-Radiography Utilization Study criteria for nonimaging (down from 16.1% in phase 2), and 15 (4%) required no imaging when both National Emergency X-Radiography Utilization Study and abbreviated Canadian cervical spine rule criteria were applied. CONCLUSIONS Implementation of a clinical education initiative resulted in improved adherence to ACR Appropriateness Criteria and improved clinical effectiveness of the studies by increasing fracture detection rate. Initiatives such as these could potentially influence imaging overutilization without burdening emergency department clinicians with excessive roadblocks to image ordering.

Perfusion imaging in neuro-oncology: basic techniques and clinical applications.

Perfusion imaging is a method for assessing the flow of blood occurring at the tissue level and can be accomplished by both CT and MR perfusion techniques. The use of perfusion imaging has increased substantially in the past decade, particularly in neuro-oncologic imaging, where it is has been used for brain tumor grading and directing biopsies or targeted therapy, as well as for the evaluation of treatment response and disease progression. This article discusses the basic principles and techniques of perfusion imaging, as well as its applications in neuro-oncology.

Acute Calcific Longus Colli Tendinitis: An Unusual Location and Presentation

Acute calcific longus colli tendinitis (LCT) has been reported as an unusual cause of acute-onset neck pain, dysphagia, and headache.(1-5) As described in most of the published reports, LCT traditionally manifests on computed tomography (CT) imaging as paramidline calcium hydroxyapatite crystal deposits anterior to the C1 and C2 vertebral bodies. However, recent studies have brought attention to the disease existing at the C4-C5 and C5-C6 levels.(6,7) Acute LCT is considered relatively benign, typically resolving on its own within several weeks.