Utility of dual-energy CT virtual keV monochromatic series for the assessment of spinal transpedicular hardware-bone interface.

OBJECTIVE: Our aim was to evaluate the utility of dual-energy CT (DECT) virtual kilo-electron volt (keV) monochromatic images for the visualization of the transpedicular screw-bone interface after spinal fusion. MATERIALS AND METHODS: This retrospective study included postfusion spine CT studies performed from October 2011 through April 2012 on a dual-energy 64-MDCT unit (Discovery CT750 HD). Studies were postprocessed on an Advantage Windows workstation (version 4.4) by two neuroradiologists with creation of monochromatic images from 40 to 140 keV. Each reader graded the screw-bone interfaces on the 70-keV images (used for clinical interpretation) and on the monochromatic series using a 5-point scale (1 [uninterpretable] to 5 [excellent]). The grades of the interfaces were compared using the Wilcoxon signed rank test to detect differences between the 70-keV image and the monochromatic series. RESULTS: Ninety-two transpedicular screws in 10 patients were studied. Significant improvement in the visibility of the hardware-bone interface was seen on the monochromatic series compared with the 70-keV images: The median grade for the monochromatic series was 4 (range, 2-5) for both readers, whereas the median grade for the 70-keV images was 3 (range, 2-4) for reader 1 and 2 (range, 2-3) for reader 2 (both, p < 0.001). The interobserver agreement using weighted kappa was 0.51 for grading screw-bone interface visualization. The volume CT dose index was 29.5 mGy in all patients and the mean dose-length product was 805.2 mGy × cm. CONCLUSION: Monochromatic images generated on gemstone spectral DECT are beneficial in the reduction of metallic streak artifact and enable better visualization of the hardware-bone interface than the 70-keV series in patients treated with spinal transpedicular screw fixation.

Differentiation of benign and malignant neck pathologies: preliminary experience using spectral computed tomography.

PURPOSE: The objective of this study was to evaluate spectral Hounsfield unit (HU) curves and effective Z (atomic number) generated on dual-energy gemstone spectral imaging computed tomography (CT) in the differentiation of benign and malignant neck pathologic findings. METHODS: This was a retrospective review of 38 patients who underwent neck CT on a gemstone spectral imaging dual-energy CT (Lightspeed CT750 HD 64-slice CT scanner; GE Medical Systems, Milwaukee, Wis) from November 2009 to June 2012 with identifiable masses. One board-certified radiologist placed regions of interest within the mass (19 benign, 19 malignant) and in paraspinal muscles (PSMs) to create 2 spectral HU curves in each patient. The curve parameters compared between the benign and malignant groups included range (conceptually, the difference between the highest and lowest HU), asymptote, decay, and the differences and ratios (of lesion to PSM) of each of these 3 parameters. A logistic regression model was built with these parameters and effective Z. RESULTS: The difference in ranges (between lesion and PSM) was the best predictor of malignancy, with a threshold of 75 or greater demonstrating 95% sensitivity, 89% specificity, and 91.8% area under the curve (AUC). Adding other spectral HU parameters and effective Z to the model did not substantially increase the AUC (93.3%, difference between the 2 models not statistically significant, P > 0.25). The effective Z showed a 79.9% AUC with 68% sensitivity and 68% specificity at an 8.80 cutoff. CONCLUSIONS: The spectral HU curve is promising for differentiating benign and malignant neck pathologic findings, with the difference in range between the lesion and PSM showing the best predictive value.

Sonographically guided lumbar puncture in pediatric patients.

Our aim with this study was to develop a user-friendly method for pediatric sonographically guided lumbar punctures so that we can visualize intrathecal anatomy, confirm intrathecal injection at the time of injection, and, most importantly, avoid ionizing radiation to a child's already radiosensitive pelvis. Sonographically guided lumbar puncture was prospectively performed in children aged 7 weeks to 16 years. All attempts (n = 9) were successful. We were able to identify relevant anatomy (including the conus in children 10 years and younger), confirm intrathecal injection, visualize intrathecal hematoma, and avoid radiation. Sonography is a promising modality for image-guided lumbar punctures without radiation in children.

Practical Tips and a Template for Developing Your Curriculum Vitae.

The Alliance of Leaders in Academic Affairs in Radiology (ALAAR) advocates for a Universal Curriculum Vitae for all medical institutions and to that end, we have developed a template that can be downloaded on the AUR website (ALAAR CV template) that includes all of the elements required by many academic institutions. Members of ALAAR represent multiple academic institutions and have spent many hours reviewing and providing input on radiologists' curricula vitae. The purpose of this review is to help academic radiologists accurately maintain and optimize their CVs with minimal effort and to clarify common questions that arise at many different institutions in the process of constructing a CV.

Incidental findings on cranial imaging in nonagenarians.

OBJECT: The aim of this article was to report on the nature and prevalence of incidental imaging findings in a consecutive series of patients older than 90 years of age who underwent intracranial imaging for any reason. METHODS: The authors retrospectively reviewed the electronic medical and imaging records of consecutive patients who underwent brain MR imaging at a single institution over a 153-month interval and were at least 90 but less than 100 years of age at the time of the imaging study. The prevalence of lesions by type in this consecutive series of MR imaging evaluations was calculated for all patients. The authors reviewed the medical record to evaluate whether a change in management was recommended based on MR imaging findings. They evaluated patient age at the time of death and the time interval between MR imaging and death. RESULTS: The authors identified 177 patients who met the study criteria. The group included 119 women (67%) and 58 (33%) men. Their mean age was 92.3 ± 1.8 years. Evidence of acute ischemic changes or cerebrovascular accident (CVA) was found in 36 patients (20%). Fifteen patients (8%) had an intracranial tumor. Intracranial aneurysms were incidentally identified in 6 patients (3%). Chronic subdural hematomas were found in 3 patients (2%). Overall, 25 patients (14%) had some change in medical management as a result of the MR imaging findings. The most common MR imaging finding that resulted in a change in medical management was an acute CVA (p < 0.0001). The mean time to death from date of MR imaging was 2.5 ± 2.3 years. CONCLUSIONS: Intracranial imaging is rarely performed in patients older than 90 years. In cases of suspected stroke, MR imaging findings may influence treatment decisions. Brain MR imaging studies ordered for other indications in this age group rarely influence treatment decisions. Incidentally discovered lesions in this age group are generally not treated.

Management and outcomes of patients undergoing surgery for traumatic cervical fracture-subluxation associated with an asymptomatic vertebral artery injury.

STUDY DESIGN: Retrospective clinical series. OBJECTIVE: To evaluate the management and outcomes of patients with unilateral, asymptomatic vertebral artery occlusion (VAO) undergoing surgery for cervical fractures associated with subluxation. SUMMARY OF BACKGROUND DATA: The management of VAO is controversial with several treatment options available, including observation alone, antiplatelet therapy, or anticoagulation therapy. METHODS: A chart review inclusive of the years 2004 to 2006 was performed to include patients who presented after nonpenetrating trauma with cervical fracture associated with subluxation requiring surgery. An associated asymptomatic VAO was also required for inclusion. Eight patients were identified. RESULTS: Seven patients were male and the mean age was 26.8 years. Six patients suffered an associated spinal cord injury. Three patients underwent closed reduction before surgical stabilization. Five patients underwent open reduction with stabilization. No patient received treatment for VAO before reduction. Postoperative treatment for VAO was variable, with 5 of 8 patients undergoing observation alone. The remaining 3 patients were treated with aspirin therapy, although 1 patient received heparin intravenously for 1 day. None of the patients experienced an ischemic complication. CONCLUSIONS: Reduction of a fracture, whether closed or open, without treatment of an associated asymptomatic VAO seems safe. Postoperative management of VAO consisting of either observation alone or aspirin therapy also seems to be a safe option.

Calcifying pseudoneoplasm of the spine.

Calcifying pseudoneoplasms have been rarely reported to involve the spine. Diagnostically, MRI characteristics have not been well-described. We present the case of a 59-year-old woman with a C8 radiculopathy and history significant for metastatic breast cancer. MRI showed a C7-T1 extradural mass with an isointense signal to the spinal cord on T1- and T2-weighted sequences. Mild peripheral enhancement was also noted. The patient underwent a laminectomy to accomplish resection of the underlying lesion. The mass was firm, tan-colored, and adherent to the adjacent dura. A gross total resection was achieved and, postoperatively, the patient had resolution of her radiculopathy. Pathologic analysis confirmed a calcifying pseudoneoplasm. Calcifying pseudoneoplasms can cause exclusively axial pain or may induce radicular or myelopathic symptoms. The pathogenesis is unclear, although the lesions are usually benign. MRI findings can vary, but typically the lesions are extradural, well-demarcated, and mildly enhance peripherally. Surgical resection, either subtotal or total, is highly successful.

Artery of Percheron Infarct: 12 Cases and Their Complex Clinical Courses.

Strokes involving the artery of Percheron (AOP), an anatomic variant of thalamic vascular supply, are rare. Little is known about the inpatient hospital course for these patients. We retrospectively identified consecutive patients with AOP in their medical charts from a university-based tertiary care hospital from January 1, 2000, to August 15, 2017. A chart review identified demographics, transfer status, in-hospital versus community onset of stroke, emergency medical services (EMS) use, presenting signs/symptoms, time to radiologic diagnosis (from time of presentation to tertiary care hospital or from time of initial symptom onset in an already hospitalized patient), tissue plasminogen activator (tPA) use, intensive care unit (ICU) stays, intubation, length of stay (LOS), and discharge location. After radiologic inclusion/exclusion criteria were applied, 12 patients were included in the study. There were 7 men and 5 women, and the mean age (SD) was 68 (15). Seven were transfers, and 4 had an in-hospital stroke. Of the 8 community-onset strokes, 7 utilized EMS. Mental status changes occurred in 11 of 12 and ocular disturbances in all patients. Time to radiologic diagnosis averaged 1.9 (median = 1.1) days. One patient received tPA. Eight received care in the ICU. Four were intubated. Average LOS was 8.3 days. Four were discharged home, 3 entered inpatient rehabilitation facilities, and 5 entered skilled nursing facilities. In-hospital stroke status further complicates the already challenging diagnosis of AOP infarct, and clinicians must maintain a high suspicion for this rare stroke in order to quickly diagnose and intervene.

Peripheral primitive neuroectodermal tumor/Ewing's sarcoma of the craniospinal vault: case reports and review.

The peripheral primitive neuroectodermal tumor/Ewing's sarcoma family tumor (pPNET/ESFT) group includes small round cell tumors of the bone, soft tissue, and nerve with morphological attributes of the germinal neuroepithelium. Peripheral PNETs/ESFTs also occur within the craniospinal vault, a region including the central nervous system, the meninges, and the cranial and spinal nerve roots. Gene rearrangements between the EWS gene on chromosome 22q12 and members of the ETS gene family are common in and specific to pPNETs/ESFTs. Another defining characteristic of pPNETs/ESFTs is their membranous expression of the MIC2 gene product. We describe 2 cases of pPNETs within the craniospinal vault. An intradural tumor arising from the nerve roots of the cauda equina was discovered in a 32-year-old man presenting with radiculopathic back pain and lower-extremity weakness. An intracranial pPNET that mimicked a meningioma was found in a 21-year-old man presenting with headache and visual disturbances. MIC2 gene product expression and EWS/ETS gene rearrangement were detected in both case patients. The literature with regard to pPNETs/ESFTs arising within the craniospinal vault is reviewed.

Magnetic resonance spectroscopy of head and neck neoplasms.

Magnetic resonance spectroscopy (MRS) is a validated noninvasive method for evaluation of possible malignant tumor and lymph nodes of the head and neck. From its roots as a budding research application, it has made the critical transition to a widespread clinical tool. MRS analyzes the tissue at a molecular level and searches for the presence of specific metabolites, which are markers for malignancy. Differentiation of benign from malignant neoplasm, detection of recurrence of malignant tumor and noninvasive treatment monitoring of treated or untreated tumor are some of the important utilities of MRS. One dimensional 1H-MRS is the most popular and promising technique for spectroscopic analysis while P-31 MRA and two-dimensional correlated spectroscopy (2D COSY) have also showed some promise. This article describes the application of magnetic resonance spectroscopy for evaluation of malignant tumors of the neck.

MR imaging of brachial plexus.

The brachial plexus is a complex anatomic component originating from ventral rami of the lower cervical nerve roots from C5 to C8 and upper thoracic spinal nerve roots from T1, providing sensory and motor innervation to the upper extremities. As it is inaccessible to palpation, clinical evaluation of the brachial plexus is very challenging and localizing lesions along its course is very difficult. The gamut of pathologic conditions involving the brachial plexus includes primary tumor, direct extension of adjacent tumor, metastasis, trauma, or an inflammatory condition. MR imaging provides superior diagnostic ability due to its ability of multiplanar imaging and greater soft tissue contrast. This article discusses MR imaging findings in a variety of pathologic conditions, with special emphasis on neoplastic process.

Dynamic contrast-enhanced MR imaging.

Dynamic contrast-enhanced magnetic resonance imaging is a useful clinical tool in evaluation of soft tissue neoplasm and lymph nodes in head and neck. It is thought to be a useful predictor of response to radiotherapy for head and neck carcinoma and used to monitor the treatment and distinguish post-therapeutic changes from recurrent mass with greater confidence. It can be used to distinguish between normal and malignant tissue and to differentiate a malignant lymphoma from other lymph nodal enlargements. The technique utilizes relative differences in microvasculature and microcirculation between malignant and non-malignant tissue to achieve greater contrast in signal imaging following bolus contrast administration. This article explains the underlying principles and imaging techniques for this new diagnostic tool. The clinical applications and technical challenges are discussed. The future challenges and some contradictions in results are also outlined.

MR imaging of salivary glands.

In conclusion, if a parotid gland mass is bilateral, it is more likely to be Warthin's tumor, especially if it does not enhance. Less likely, it could be lymphoepithelial cyst or necrotic lymph node. A unilateral, non-enhancing mass with a high T2 signal is more likely to be a Warthin's tumor and less likely a necrotic lymph node or first branchial cleft cyst. If the mass is unilateral, shows postcontrast enhancement, has a high T2 signal, and does not invade surrounding tissue planes, it is more likely to be a pleomorphic adenoma. An intermediate to low T2 signal mass-with or without invasion of surrounding tissue planes--is more likely to be a malignant mass such as adenocystic or mucoepidermoid carcinoma. Biopsy is superior and the gold standard for diagnosis and cannot be replaced by MR imaging, however.

Newer MR imaging techniques for head and neck.

Dynamic and functional imaging techniques are being developed to improve the evaluation of various pathologic processes of the head and neck region. These techniques include dynamic contrast-enhanced MR imaging for evaluating soft tissue masses and cervical lymph nodes, the use of ultrasmall superparamagnetic iron oxide contrast agent, and functional techniques such as in vivo and in vitro MR spectroscopy of head and neck cancer and lymph nodes and apparent diffusion coefficient mapping of parotid glands. These techniques can help to differentiate nonmalignant tissue from malignant tumors and lymph nodes and can aid in differentiating residual malignancies from postradiation changes. From methodological development, they are making the critical transition to preclinical and clinical validating methods and eventually to widespread clinical tools.