Keith R. Peters

Vertebroplasty for osteoporotic compression fractures: current practice and evolving techniques.

PERCUTANEOUS VERTEBROPLASTY WAS developed in France by Deramond et al., who provided initial reports of the procedure in 1987. This minimally invasive procedure uses a large-bore bone-cutting needle to percutaneously access a vertebral body, inject bone cement, and thereby stabilize and reinforce the remaining bone structure. The procedure was used initially to treat aggressive hemangiomas, but it then was extended to the treatment of osteolytic metastases and myeloma and currently osteoporotic compression fractures refractory to medical therapy. In this article, we review the current technique and its indications along with emerging devices and areas of current research.

A better landmark for positioning a central venous catheter.

Background.Improper positioning of central venous catheters (CVCs) can lead to erosion through the superior vena cava (SVC) or right atrium (RA) and pericardial tamponade. It is widely recommended that the tip of CVCs be placed above the heart or the pericardial reflection. The purpose of this study was to identify an easily recognized landmark to allow identification of the proximal extent of the pericardial reflection on a routine chest radiograph (CXR). Methods.We analyzed the computerized tomograms of the chest from 97 adults to evaluate the relationship between the pericardial reflection, SVC, carina, and right mainstem bronchus. Correlations between demographic data and length of SVC or pericardial reflection were sought. Results.The mean length of the SVC was 6.5 cm. The pericardial reflection covered an average of 3.6 cm of the distal SVC. The carina was a mean of 1.3 cm below the mid-point of the SVC and 0.7 cm below the pericardial reflection. There was no significant correlation between SVC or pericardial length and either age, height, or weight. Conclusions.The distal half of the SVC lies within the pericardial reflection, and the upper limit of the pericardial reflection is slightly above the level of the carina. These landmarks are useful for determining proper position of the tip of a CVC on CXR.

Adult patient doses in interventional neuroradiology

We investigated radiation doses to 149 adult patients who underwent interventional neuroradiologic procedures, consisting of 132 patients who had diagnostic imaging examinations and 17 patients who had therapeutic procedures. The interventional procedures were carried out on a biplane system capable of performing fluoroscopy and digital subtraction angiography (DSA). The x-ray imaging system was interfaced to a patient dosimetry system, which computed surface (skin) doses based on the selected radiographic technique factors in each of the radiographic and fluoroscopic imaging modes. For each patient, an assessment was made of the maximum surface dose received during the procedure, which predicts the possibility of inducing deterministic effects. Knowledge of the surface doses, beam quality and x-ray cross sectional area permitted the computation of the total energy imparted to each patient. Energy imparted values were converted to effective dose, which provides an estimate of the stochastic radiation risk to the patient. The median surface dose for the frontal plane during diagnostic imaging examinations was 1.3 Gy, with a maximum surface dose of 5.1 Gy. The median surface dose for the frontal plane during therapeutic procedures was 2.8 Gy with a maximum surface dose of 5.0 Gy. Ratios of the lateral to frontal median surface doses were 0.47 for diagnostic examinations and 0.68 for interventional procedures. The median energy imparted was 1.8 J during fluoroscopy, and 4.3 J during radiography, showing that on average, 66% of the patient exposure comes from radiographic imaging (DSA). For diagnostic examinations, the median patient effective dose was 33 mSv, with a maximum of 152 mSv. For therapeutic procedures, the median patient effective dose was 74 mSv, with a maximum of 156 mSv. In interventional neuroradiology, surface doses could induce deterministic effects, and the corresponding effective doses are noticeably higher than those normally encountered in diagnostic radiology.

Effect of radiographic techniques (kVp and mAs) on image quality and patient doses in digital subtraction angiography

We investigated how varying the x-ray tube voltage and image receptor input exposure affected image quality and patient radiation doses in interventional neuroradiologic imaging. Digital subtraction angiography (DSA) images were obtained of a phantom with 1 mm diameter vessels containing iodine at concentrations between 4.5 and 50 mg/cc. The detection threshold concentration of iodine was determined by inspecting DSA images obtained at a range of x-ray tube voltages and input exposure levels. Surface doses were obtained from measured x-ray tube output data, and corresponding values of energy imparted were determined using the exposure-area product incident on the phantom. In one series of experiments, the air kerma at the image intensifier (X) was varied between 0.44 microGy per frame and 8.8 microGy per frame at a constant x-ray tube voltage of 70 kVp. In a second series of experiments, the tube voltage was varied between 50 and 100 kVp, and the mAs adjusted to maintain a constant exposure level at the input of the image intensifier. At a constant x-ray tube voltage, the surface dose and energy imparted were directly proportional to the input exposure per frame used to acquire the DSA images. On our DSA system operated below 2.2 microGy per frame, the threshold iodine concentration was found to be proportional to X(-0.57), which is in reasonable agreement with the theoretical prediction for a quantum noise limited imaging system. Above 2.2 microGy per frame, however, the threshold iodine concentration was proportional to X(-0.26), indicating that increasing the input exposure above this value will only achieve modest improvements in image quality. At a constant image intensifier input exposure level, increasing the x-ray tube voltage from 50 kVp to 100 kVp reduced the surface dose by a factor of 6.1, and the energy imparted by a factor of 3.5. The detection threshold iodine concentration was found to be proportional to kVp(n), where n was 2.1 at 1.1 microGy per frame, and 1.6 at 3.9 microGy per frame. For clinical situations that can be modeled by a uniform phantom, reducing the x-ray tube voltage rather than increasing the exposure level would best achieve improvements on our DSA imaging system performance.

Embolization of a Dural Arteriovenous Fistula of the Ventral Cervical Spinal Canal in a Nine-Year-Old Boy

A 9-year-old patient presented with an acute left hemiparesis secondary to an intradural hemorrhage of the cervical spinal cord. Angiography revealed a dural arteriovenous (AV) fistula with multiple venous aneurysms fed by a radicular branch of the right vertebral artery. This AV fistula did not contribute blood flow to the cervical segment of the spinal cord, which was tested by an intra-arterial injection of methohexital. Interruption of the fistula was possible by transluminal embolization with polyvinyl alcohol and silk. At a 6-month follow-up, the patient was neurologically intact, and angiography demonstrated no AV fistula. This case illustrates an unusual presentation of a dural AV fistula. Dural AV fistulas are rare in the cervical region and extremely unusual in patients less than 20 years of age. The lesion proved to be amenable to transluminal embolization alone, without the need for surgery, with a dramatic resolution of the neurological deficit.

Delayed exacerbation of third nerve palsy due to aneurysmal regrowth after endovascular coil embolization.

A 72-year-old woman with a painful left third cranial nerve palsy due to a basilar artery aneurysm situated between the superior cerebellar and posterior cerebral arteries was treated with Guglielmi detachable coils (GDCs). Despite a good initial angiographic result with a small residual neck and improvement in the ocular motility and pain, the patient experienced worsening of the third cranial nerve palsy 15 months later. Cerebral angiography confirmed coil compaction with aneurysmal regrowth. A second endovascular coil embolization resulted in complete obliteration of the aneurysm. The patient experienced complete resolution of the pain and partial resolution of the third cranial nerve palsy. In some patients, a small residual aneurysm neck after endovascular embolization therapy with GDCs can result in delayed aneurysmal regrowth due to coil compaction. Clinical manifestations may herald this dangerous regrowth.

Who gets post-concussion syndrome? An emergency department-based prospective analysis.

BackgroundThe objective of this study was to determine who gets post-concussion syndrome (PCS) after mild traumatic brain injury or head injury.MethodsPatients presented within an hour of mild traumatic brain injury (mTBI). Written informed consent was obtained from all patients, who then provided detailed answers to surveys at the time of injury as well as at 1 week and 1 month follow-up. Statistical analyses were performed using JMP 11.0 for the Macintosh.ResultsThe most commonly reported symptoms of PCS at first follow-up were headache (27%), trouble falling asleep (18%), fatigue (17%), difficulty remembering (16%), and dizziness (16%). Furthermore, only 61% of the cohort was driving at 1 week follow-up, compared to 100% prior to the injury.Linear regression analysis revealed the consumption of alcohol prior to head injury, the mechanism of head injury being a result of motor vehicle collision (MVC) or fall, and the presence of a post-injury headache to be significantly associated with developing PCS at 1 week follow-up, while the occurrence of a seizure post-injury or having an alteration in consciousness post-injury was significantly associated with developing PCS at 1 month follow-up. On multivariate regression analysis, the presence of a headache post-injury was the most robust predictor, retaining statistical significance even after controlling for age, gender, and presence of loss of consciousness (LOC), alteration of consciousness (AOC), post-traumatic amnesia (PTA), seizure, or vomiting.ConclusionsThe results of this prospective study suggest that headache right after the head injury, an alteration of consciousness after the head injury, and alcohol consumption prior to the head injury are significant predictors of developing PCS, which occurs with equal frequency in men and women. Early identification of those who are at risk of developing PCS would diminish the burden of the injury and could potentially reduce the number of missed work and school days.

Anterior Third Ventricle Meningioma in an Adolescent: A Case Report

A case of an anterior third ventricular meningioma in a 17-year-old girl is presented. Gross total resection of this tumor with minimal morbidity was accomplished by transcallosal exposure through a frontal craniotomy. A review of the literature implies that surgical morbidity and mortality for the removal of third ventricular meningiomas markedly improved with the use of the operating microscope. Despite advanced imaging capabilities, radiographic analysis of a solid third ventricular mass may not always determine tissue diagnosis. In addition, preoperative placement of a ventriculoperitoneal shunt will treat hydrocephalus, but may limit the surgical options for tumor exposure. The differential diagnosis for this solid anterior third ventricular mass is presented, and the method of treatment for this case is discussed.

Vessel wall enhancement in herpes simplex virus central nervous system vasculitis.

Infection is a well-known cause of cerebral vasculopathy and vasculitis. We report a 36-year-old woman with cerebral vasculitis and ischemic stroke secondary to herpes simplex virus (HSV). MRI studies revealed a pontine stroke with basilar artery stenosis and vessel wall gadolinium enhancement. This case demonstrates the ability of HSV to cause a focal brainstem vasculitis and the utility of enhanced MRI in the diagnosis of stroke related to HSV central nervous system vasculitis.

TBI surveillance using the common data elements for traumatic brain injury: a population study

BackgroundTo characterize the patterns of presentation of adults with head injury to the Emergency Department.MethodsThis is a cohort study that sought to collect injury and outcome variables with the goal of characterizing the very early natural history of traumatic brain injury in adults. This IRB-approved project was conducted in collaboration with our Institution’s Center for Translational Science Institute. Data were entered in REDCap, a secure database. Statistical analyses were performed using JMP 10.0 pro for Windows.ResultsThe cohort consisted of 2,394 adults, with 40% being women and 79% Caucasian. The most common mechanism was fall (47%) followed by motor vehicle collision (MVC) (36%). Patients sustaining an MVC were significantly younger than those whose head injury was secondary to a fall (P < 0.0001). Ninety-one percent had CT imaging; hemorrhage was significantly more likely with worse severity as measured by the Glasgow Coma Score (chi-square, P < 0.0001). Forty-four percent were admitted to the hospital, with half requiring ICU admission. In-hospital death was observed in 5.4%, while neurosurgical intervention was required in 8%. For all outcomes, worse TBI severity per GCS was significantly associated with worse outcomes (logistic regression, P < 0.0001, adjusted for age).ConclusionThese cohort data highlight the burden of TBI in the Emergency Department and provide important demographic trends for further research.