3T MRI Whole-Brain Microscopy Discrimination of Subcortical Anatomy, Part 2: Basal Forebrain.

BACKGROUND AND PURPOSE: The basal forebrain contains multiple structures of great interest to emerging functional neurosurgery applications, yet many neuroradiologists are unfamiliar with this neuroanatomy because it is not resolved with current clinical MR imaging. MATERIALS AND METHODS: We applied an optimized TSE T2 sequence to washed whole postmortem brain samples (n = 13) to demonstrate and characterize the detailed anatomy of the basal forebrain using a clinical 3T MR imaging scanner. We measured the size of selected internal myelinated pathways and measured subthalamic nucleus size, oblique orientation, and position relative to the intercommissural point. RESULTS: We identified most basal ganglia and diencephalon structures using serial axial, coronal, and sagittal planes relative to the intercommissural plane. Specific oblique image orientations demonstrated the positions and anatomic relationships for selected structures of interest to functional neurosurgery. We observed only 0.2- to 0.3-mm right-left differences in the anteroposterior and superoinferior length of the subthalamic nucleus (P = .084 and .047, respectively). Individual variability for the subthalamic nucleus was greatest for angulation within the sagittal plane (range, 15°-37°), transverse dimension (range, 2-6.7 mm), and most inferior border (range, 4-7 mm below the intercommissural plane). CONCLUSIONS: Direct identification of basal forebrain structures in multiple planes using the TSE T2 sequence makes this challenging neuroanatomy more accessible to practicing neuroradiologists. This protocol can be used to better define individual variations relevant to functional neurosurgical targeting and validate/complement advanced MR imaging methods being developed for direct visualization of these structures in living patients.

3T MRI Whole-Brain Microscopy Discrimination of Subcortical Anatomy, Part 1: Brain Stem.

BACKGROUND AND PURPOSE: The brain stem is compactly organized with life-sustaining sensorimotor and autonomic structures that can be affected by numerous pathologies but can be difficult to resolve on conventional MR imaging. MATERIALS AND METHODS: We applied an optimized TSE T2 sequence to washed postmortem brain samples to reveal exquisite and reproducible brain stem anatomic MR imaging contrast comparable with histologic atlases. This resource-efficient approach can be performed across multiple whole-brain samples with relatively short acquisition times (2 hours per imaging plane) using clinical 3T MR imaging systems. RESULTS: We identified most brain stem structures at 7 canonical axial levels. Multiplanar or oblique planes illustrate the 3D course and spatial relationships of major brain stem white matter pathways. Measurements of the relative position, course, and cross-sectional area of these pathways across multiple samples allow estimation of pathway location in other samples or clinical subjects. Possible structure-function asymmetries in these pathways will require further study-that is, the cross-sectional area of the left corticospinal tract in the midpons appeared 20% larger (n = 13 brains, P < .10). CONCLUSIONS: Compared with traditional atlases, multiplanar MR imaging contrast has advantages for learning and retaining brain stem anatomy for clinicians and trainees. Direct TSE MR imaging sequence discrimination of brain stem anatomy can help validate other MR imaging contrasts, such as diffusion tractography, or serve as a structural template for extracting quantitative MR imaging data in future postmortem investigations.

A prospective study of women with ASCUS or LSIL pap smears at baseline and HPV E6/E7 mRNA positive: a 3-year follow-up.

Human papillomavirus (HPV) testing is used in the triage of women with a borderline smear result. The efficiency of testing women with a low-grade squamous intraepithelial lesion (LSIL) and atypical squamous cells of undetermined significance (ASCUS) is less clear. For this reason we used a new HPV test that detects E6/E7 messenger RNA (mRNA), which might have a higher specificity. The objective of this prospective study was to assess whether HPV E6/E7 mRNA positivity in women with ASCUS and LSIL at baseline, is able to predict those women who have a high risk of developing a histological cervical intraepithelial neoplasia (CIN2) or worse lesion. We took into consideration the women's age and HPV DNA genotype and followed them up for 3 years. Cervical samples from women with high-risk HPV (HR-HPV) DNA-positive ASCUS (n = 90) or LSIL (n = 222) were tested for the presence of HR-HPV E6/E7 mRNA and the women were monitored for the development of histopathologically verified CIN2+. Thirteen patients with ASCUS and 17 with LSIL did not complete follow-up. All patients with LSIL and ASCUS, enrolled in this study, had confirmed lesions at the colposcopic examination. Follow-up was available for 312 women, 193 were positive in the HR-HPV DNA test and 93 had a HPV E6/E7 mRNA positive test. Finally, 22 women positive in the HPV DNA test for high-risk genotypes and with positive E6/E7 mRNA had a histologically confirmed CIN2+. Only two cases with negative HPV E6/E7 mRNA had CIN2+. The study shows that women positive in the HPV E6/E7 mRNA test have a greater risk of malignant progression of cervical lesions and therefore deserve greater attention and earlier check-ups.

Palliative CT-Guided Cordotomy for Medically Intractable Pain in Patients with Cancer.

Palliative cervical cordotomy can be performed via percutaneous radiofrequency ablation of the lateral C1-2 spinothalamic tract. This rare procedure can be safe, effective, and advantageous in mitigating medically intractable unilateral extremity pain for selected patients with end-stage cancer. This report reviews the indications, techniques, risks, and potential benefits of cordotomy. We describe our recent experience treating 3 patients with CT-guided C1-2 cordotomy and provide the first characterization of spinal cord diffusion MR imaging changes associated with successful cordotomy.

New Clinically Feasible 3T MRI Protocol to Discriminate Internal Brain Stem Anatomy.

Two new 3T MR imaging contrast methods, track density imaging and echo modulation curve T2 mapping, were combined with simultaneous multisection acquisition to reveal exquisite anatomic detail at 7 canonical levels of the brain stem. Compared with conventional MR imaging contrasts, many individual brain stem tracts and nuclear groups were directly visualized for the first time at 3T. This new approach is clinically practical and feasible (total scan time = 20 minutes), allowing better brain stem anatomic localization and characterization.

Heart rate variability is an independent predictor of morbidity and mortality in hemodynamically stable trauma patients.

BACKGROUND: Reduced heart rate variability (HRV) reflects autonomic dysfunction and can triage patients better than routine trauma criteria or vital signs. However, there is questionable specificity and no consensus measurement technique. The purpose of this study was to analyze whether factors that alter autonomic function affect the specificity of HRV for assessing traumatic injury. METHODS: We evaluated 216 hemodynamically stable adults (3:1 M:F; 97:3 blunt:penetrating; age 49 years ± 1 year, mean ± standard error) undergoing computed axial tomography (CT) scan to rule out traumatic brain injury (TBI). All were prospectively instrumented with a Mars Holter system (GE Healthcare, Milwaukee, WI). HRV was determined offline using time domain (standard deviation of normal-normal intervals, root-mean-square successive difference) and frequency domain (very low frequency [VLF], LF, wideband frequency, high frequency [HF], low to HF index ratio) calculations from 15-minute electrocardiogram and correlated with routine vital signs, mortality, TBI, morbidity, length of stay (LOS), and comorbidities. Significance (p ≤ 0.05) was determined using nonparametric analysis, Student's t test, analysis of variance, or multiple logistic regression. RESULTS: VLF alone predicted survival, severity of TBI, intensive care unit LOS, and hospital LOS (all p < 0.05). Beta-blockers or diabetes had no effect, whereas age, sedation, mechanical ventilation, spinal cord injury, and intoxication influenced one or more of the variables with age being the most powerful confounder (all p < 0.05). Except for the Glasgow Coma Scale, no other routine trauma or hemodynamic criteria correlated with any of these outcomes. CONCLUSIONS: Decreased VLF is an independent predictor of mortality and morbidity in hemodynamically stable trauma patients. Other time and other frequency domain variables correlated with some, but not all, outcomes. All were heavily influenced by factors that alter autonomic function, especially patient age.

Bispectral index to monitor propofol sedation in trauma patients.

BACKGROUND: This study tested the hypothesis that the bispectral index (BIS) is reliable relative to clinical judgment for estimating sedation level during daily propofol spontaneous awakening trials (SATs) in trauma patients. METHODS: This was a prospective observational trial with waiver of consent conducted in the intensive care unit of Level I trauma center in 94 mechanically ventilated trauma patients sedated with propofol alone or in combination with midazolam. BIS, Richmond Agitation Sedation Scale (RASS), electromyography, and heart rate variability, as a test of autonomic function, were measured for 45 minutes during daily SATs. Data were evaluated with analysis of variance, linear regression, and nonparametric tests. RESULTS: The BIS wave form coincided almost exactly with propofol on/off. Steady-state BIS correlated with RASS (p < 0.0001) and with propofol dose (p < 0.0001), but the strengths of association were relatively low (all r(2) < 0.5). BIS wave form was not altered by age, heart rate, or heart rate variability and was similar with propofol alone or propofol plus midazolam, but the presence of brain injury or the use of paralytics shifted the curve downward (both p < 0.001). The overall test characteristics for BIS versus RASS without neuromuscular blockade were sensitivity: 90% versus 77% (p = 0.034); specificity: 90% versus 75% (p = 0.021); positive predictive value: 90% versus 76% (p = 0.021), and negative predictive value: 90% versus 76% (p = 0.021). CONCLUSIONS: In the first trial in trauma patients and largest trial in any surgical population, the (1) BIS was reliable and has advantages over RASS of being continuous and objective, at least during a propofol SAT; (2) BIS interpretation remains somewhat subjective in patients receiving paralytic agents or with traumatic brain injury.

Emergency department assessment and management of facial trauma from war-related injuries.

Facial trauma related to combat injury is of increasing prevalence and complex in nature when associated with the multiply injured trauma victim. Although rarely life-threatening, the treating physician must be aware of the presence of facial trauma and its associated injuries to seamlessly treat the combat casualty in accordance to the Advanced Trauma Life Support protocol while maintaining the armed forces' ultimate goals of returning "the greatest possible number of soldiers to combat and the preservation of life, limb and eyesight in those who must be evacuated." To this end, the treating physician must maintain a high index of suspicion for injury and have various maneuvers available to handle immediate threats to life, limb, or sight. This article will review the proper emergency department assessment and management of prevalent injuries associated with war-related facial trauma.

Predeployment mass casualty and clinical trauma training for US Army forward surgical teams.

Since the beginning of the program in 2002, 84 Forward Surgical Teams (FSTs) have rotated through the Army Trauma Training Center (ATTC) at the University of Miami/Ryder Trauma Center including all those deployed to Iraq and Afghanistan. The purpose of this study was to provide the latest updates of our experience with FSTs at the ATTC. Before deployment, each FST participates in a 2-week training rotation at the ATTC. The rotation is divided into 3 phases. Phase 1 is to refresh FST knowledge regarding the initial evaluation and management of the trauma patient. Phase 2 is the clinical phase and is conducted entirely at the Ryder Trauma Center. The training rotation culminates in phase 3, the Capstone exercise. During the Capstone portion of their training, the entire 20-person FST remains at the Ryder Trauma Center and is primarily responsible for the evaluation and resuscitation of all patients arriving over a 24-hour period. Subject awareness concerning their role within the team improved from 71% to 95%, indicating that functioning as a team in the context of the mass casualty training exercise along with clinical codes was beneficial. The clinical component of the rotation was considered by 47% to be the most valuable aspect of the training. Our experience strongly suggests that a multimodality approach is beneficial for preparing a team of individuals with minimal combat (or trauma) experience for the rigors of medical care and triage on the battlefield. The data provided by participants rotating through the ATTC show that through clinical exposure and simulation over a 2-week period, FST performance is optimized by defining provider roles and improving communication. The mass casualty training exercise is a vital component of predeployment training that participants feel is valuable in preparing them for the challenges that lay ahead.

First report on safety and efficacy of hetastarch solution for initial fluid resuscitation at a level 1 trauma center.

BACKGROUND: For logistics, the US Army recommends Hextend (Hospira; 6% hetastarch in buffered electrolyte, HET) for battlefield resuscitation. To support this practice, there are laboratory data, but none in humans. To test the hypothesis that HET is safe and effective in trauma, we reviewed our first 6 months of use at a civilian level 1 trauma center. STUDY DESIGN: From June 2008 to December 2008, trauma patients received standard of care (SOC) +/- 500 to 1,000 mL of HET within 2 hours of admission at surgeon discretion. Each case was reviewed, with waiver of consent. RESULTS: There were 1,714 admissions; 805 received HET and 909 did not. With HET versus SOC, overall mortality was 5.2% versus 8.9% (p = 0.0035) by univariate analysis. Results were similar after penetrating injury only (p = 0.0016) and in those with severe injury, defined by Glasgow Coma Scale <9 (p = 0.0013) or Injury Severity Score >26 (p = 0.0142). After HET, more patients required ICU admission (40.9% vs. 34.5%; p = 0.0334) and transfusions of blood (34.4% vs. 20.2%; p = 0.0014) or plasma (20.7% vs. 12.2%; p = 0.0251), but there were no treatment-related differences in prothrombin time or partial thromboplastin time. The 24-hour urine outputs and requirements for blood, plasma, and other fluids were similar. However, increased early deaths with SOC implicate possible selection bias. If that factor was controlled for with multivariate analysis, the same trends were present, but the apparent treatment effects of HET were no longer statistically significant. CONCLUSIONS: In the first trial to date in hemodynamically unstable trauma patients, and the largest trial to date in any population of surgical patients, initial resuscitation with HET was associated with reduced mortality and no obvious coagulopathy. A randomized blinded trial is necessary before these results can be accepted with confidence.

A review of ureteral injuries after external trauma.

INTRODUCTION: Ureteral trauma is rare, accounting for less than 1% of all urologic traumas. However, a missed ureteral injury can result in significant morbidity and mortality. The purpose of this article is to review the literature since 1961 with the primary objective to present the largest medical literature review, to date, regarding ureteral trauma. Several anatomic and physiologic considerations are paramount regarding ureteral injuries management. LITERATURE REVIEW: Eighty-one articles pertaining to traumatic ureteral injuries were reviewed. Data from these studies were compiled and analyzed. The majority of the study population was young males. The proximal ureter was the most frequently injured portion. Associated injuries were present in 90.4% of patients. Admission urinalysis demonstrated hematuria in only 44.4% patients. Intravenous ureterogram (IVU) failed to diagnose ureteral injuries either upon admission or in the operating room in 42.8% of cases. Ureteroureterostomy, with or without indwelling stent, was the surgical procedure of choice for both trauma surgeons and urologists (59%). Complications occurred in 36.2% of cases. The mortality rate was 17%. CONCLUSION: The mechanism for ureteral injuries in adults is more commonly penetrating than blunt. The upper third of the ureter is more often injured than the middle and lower thirds. Associated injuries are frequently present. CT scan and retrograde pyelography accurately identify ureteral injuries when performed together. Ureteroureterostomy, with or without indwelling stent, is the surgical procedure of choice of both trauma surgeons and urologists alike. Delay in diagnosis is correlated with a poor prognosis.

Heart rate variability as a triage tool in patients with trauma during prehospital helicopter transport.

BACKGROUND: Prehospital triage of patients with trauma is routinely challenging, but more so in mass casualty situations and military operations. The purpose of this study was to prospectively test whether heart rate variability (HRV) could be used as a triage tool during helicopter transport of civilian patients with trauma. METHODS: After institutional review board approval and waiver of informed consent, 75 patients with trauma requiring prehospital helicopter transport to our level I center (from December 2007 to November 2008) were prospectively instrumented with a 2-Channel SEER Light recorder (GE Healthcare, Milwaukee, WI). HRV was analyzed with a Mars Holter monitor system and proprietary software. SDNN (standard deviation [SD] of the normal-to-normal R-R interval), as an index of HRV, was correlated with prehospital trauma triage criteria, base deficit, seriousness of injury, operative interventions, outcome, and other data extracted from the patients' medical records. There were no interventions or medical decisions based on HRV. Data were excluded only if there was measurement artifact or technical problems with the recordings. RESULTS: The demographics were mean age 47 years, 63% men, 88% blunt, 25% traumatic brain injury, 9% mortality. Prehospital SDNN predicted patients with base excess < or = -6, those defined as seriously injured and benefiting from trauma center care, as well as patients requiring a life-saving procedure in the operating room. No other available data, including prehospital en-route vital signs, predicted any of these. The sensitivity, specificity, positive predictive value, and negative predictive value were 80%, 75%, 33%, 96%, respectively, with and an overall accuracy of 76% for predicting a life-saving intervention in the operating room. CONCLUSIONS: This is the first demonstration that prehospital HRV (specifically SDNN) predicts base excess and operating room life-saving opportunities. HRV triages and discriminates severely injured patients better than routine trauma criteria or en-route prehospital vital signs. HRV may be a useful civilian or military triage tool to avoid unnecessary helicopter evacuation for minimally injured patients. A prospective, randomized trial in a larger patient population is indicated.

Maternal renal and interlobar arteries waveforms evaluation with color Doppler ultrasound in pregnancy-induced hypertension.

The authors performed a color Doppler ultrasound examination of both renal and interlobar arteries of 15 pregnant women affected by pregnancy-induced hypertension. The pulsatility index (PI), the resistance index (RI) and the systolic/diastolic ratio (S/D) values were compared with those of 15 healthy pregnant women of the same gestational age and with those of 15 nonpregnant healthy women. The authors found a significant difference (p < 0.0001) for all parameters investigated in renal and interlobar arteries between healthy pregnant women and the other two groups. No difference was found between patients with pregnancy-induced hypertension and nonpregnant healthy women. In conclusion, color Doppler ultrasound examination of both renal and interlobar arteries seems to be important for understanding the etiopathogenesis of pregnancy-induced hypertension.