Ken F. Linnau

Evidence-based approach to using CT in spinal trauma

Computed tomography has revolutionized the diagnosis and treatment planning of the acutely injured spine. In the cervical spine, its appropriate use can improve outcome and save money. Although there are no clinical prediction rules validated outside of the cervical spine, these proven capabilities have been extrapolated to the thoracolumbar spine.

Interrater agreement in the evaluation of discrepant imaging findings with the Radpeer system

OBJECTIVE The Radpeer system is central to the quality assurance process in many radiology practices. Previous studies have shown poor agreement between physicians in the evaluation of their peers. The purpose of this study was to assess the reliability of the Radpeer scoring system. MATERIALS AND METHODS A sample of 25 discrepant cases was extracted from our quality assurance database. Images were made anonymous; associated reports and identities of interpreting radiologists were removed. Indications for the studies and descriptions of the discrepancies were provided. Twenty-one subspecialist attending radiologists rated the cases using the Radpeer scoring system. Multirater kappa statistics were used to assess interrater agreement, both with the standard scoring system and with dichotomized scores to reflect the practice of further review for cases rated 3 and 4. Subgroup analyses were conducted to assess subspecialist evaluation of cases. RESULTS Interrater agreement was slight to fair compared with that expected by chance. For the group of 21 raters, the kappa values were 0.11 (95% CI, 0.06-0.16) with the standard scoring system and 0.20 (95% CI, 0.13-0.27) with dichotomized scores. There was disagreement about whether a discrepancy had occurred in 20 cases. Subgroup analyses did not reveal significant differences in the degree of interrater agreement. CONCLUSION The identification of discrepant interpretations is valuable for the education of individual radiologists and for larger-scale quality assurance and quality improvement efforts. Our results show that a ratings-based peer review system is unreliable and subjective for the evaluation of discrepant interpretations. Resources should be devoted to developing more robust and objective assessment procedures, particularly those with clear quality improvement goals.

Time factors associated with CT scan usage in trauma patients

INTRODUCTION While computed tomography (CT) scan usage in acute trauma patients is currently part of the standard complete diagnostic workup, little is known regarding the time factors involved when CT scanning is added to the standard workup. An analysis of the current time factors and intervals in a high-volume, streamlined level-1 trauma center can potentially expose points of improvement in the trauma resuscitation phase. MATERIALS AND METHODS During a 5-week period, data on current time factors involved in CT scanned trauma patients were prospectively collected. All consecutive trauma patients seen in the Emergency Department following severe trauma, or inter-hospital transfer following initial stabilizing elsewhere, and that underwent CT scanning, were included. Patients younger than 16 years of age were excluded. For all eligible patients, a complete time registration was performed, including admission time, time until completion of trauma series, time until CT imaging, and completion of CT imaging. Subgroup analyses were performed to differentiate severity of injury, based on ISS, and on primary or transfer presentations, surgery, and ICU admittance. RESULTS Median time between the arrival of the patient and completion of the screening X-ray trauma series was 9 min. Median start time for the first CT scan was 82 min. The first CT session was completed in a median of 105 min after arrival. Complete radiological workup was finished in 114 min (median). In 62% of all patients requiring CT scanning, a full body CT scan was obtained. Patients with ISS >15 had a significant shorter time until CT imaging and time until completion of CT imaging. CONCLUSION In a high-volume level-1 trauma center, the complete radiological workup of trauma patients stable enough to undergo CT scanning, is completed in a median of 114 min. Patients that are more severely injured based on ISS were transported faster to CT, resulting in faster diagnostic imaging.

Assessment of the liver strain among cirrhotic and normal livers using tagged MRI.

To use magnetization tagged magnetic resonance imaging (MRI) (tag‐MRI) to quantify cardiac induced liver strain and compare strain of cirrhotic and normal livers.

Noncontrast Functional MRI of the Kidneys

Functional magnetic resonance imaging (fMRI) techniques enable noninvasive assessment of renal function. Diffusion-weighted imaging, diffusion tensor imaging, blood oxygen level–dependent MRI, magnetic resonance elastography, and arterial spin labeling are some of the emerging techniques that have potential to investigate renal function without the use of exogenous gadolinium contrast. This article discusses the principles of these techniques, as well as their possible applications and limitations. This will introduce the readers to these novel imaging tools, which appear to have promising futures.

Variability in Management Recommendations for Incidental Thyroid Nodules Detected on CT of the Cervical Spine in the Emergency Department

PURPOSE Incidental thyroid nodules are common on CT. Variability in management recommendations for these nodules due to a lack of accepted CT base guidelines has not been demonstrated. METHODS Consecutive CT cervical spine radiology reports describing thyroid nodules performed in an emergency department from January 1, 2009, to December 31, 2011, were retrospectively reviewed. Number of nodules, nodule size, and type of recommended management were recorded. RESULTS Three hundred fifteen examinations met the inclusion criteria. The mean study age was 64 ± 20 years. Fifty-eight percent were women. Thirty percent (n = 95) of thyroid nodules measured <10 mm, 20% (n = 63) were ≥10 but <15 mm, 11% (n = 36) were ≥15 but <20 mm, and 15.5% (n = 49) were ≥20 mm. Size was not reported for 22.9% (n = 72). Two hundred twenty-seven recommendations were made in 181 (57.5%) studies. Recommendations were made for 51.6% (49 of 95) of nodules <10 mm, for 52.4% (33 of 63) of those ≥10 but <15 mm, for 83.3% (30 of 36) of those ≥15 but <20 mm, and for 81.6% (40 of 49) of those ≥20 mm. Management was recommended in 40.0% (29 of 72) of nodules with no size reported. Fifty-four percent (123 of 227) of recommendations were for ultrasound, followed by no follow-up recommended (17.2% [39 of 227]), clinical correlation (13.7% [31 of 227]), thyroid serology (6.2% [14 of 227]), clinical follow-up (4.8% [11 of 227]), comparison with prior studies (2.2% [5 of 227]), fine-needle aspiration (1.3% [3 of 227]), and nuclear scintigraphy (0.4% [1 of 227]). Nodule size was significantly associated with the likelihood of recommendation (odds ratio, 1.79; 95% confidence interval, 1.37-2.35). CONCLUSIONS Management recommendations for incidental thyroid nodules detected on cervical spine CT are made inconsistently, and the type of management recommended is variable.

Do initial radiographs agree with crash site mechanism of injury in pelvic ring disruptions? A pilot study.

Objective: Direction of injury force inferred from pelvic radiographs may be used in trauma care to predict associated injuries and guide intervention. Our objective was to compare injury direction determined from anteroposterior (AP) pelvic radiographs with injury forces determined from crash site investigation. Materials and Methods: We studied all 28 subjects from the Crash Injury Research Engineering Network (CIREN) database who met inclusion criteria of pelvic ring disruption, single-event crash, restrained front-seat occupant, diagnostic-quality pelvic radiography, and complete crash investigation data. Assessment of diagnostic quality of pelvic radiography was made by 2 radiologists who were blinded to all other subject information. Crash site investigation data included principal direction of force (PDOF), crash magnitude, and passenger compartment intrusion. An orthopedic trauma surgeon and a fellowship-trained emergency radiologist independently assessed the pelvic radiographs to determine the injury PDOF and the Young-Burgess and Tile fracture classifications, with disputes resolved by an additional emergency radiologist. Agreement between injury forces and pelvic radiographs was assessed using the kappa statistic. Results: The PDOF was anterior in 9 (32%) and lateral in 19 (68%) subjects. The readers agreed with the crash primary direction of force in 21 (75%) subjects (κ = 0.42). In subjects with lateral PDOF, agreement was 89% (17/19) compared to 44% for anterior PDOF (4/9). Interobserver agreement for the Young and Tile classification schemes was moderate (weighted kappa 0.44 and 0.54, respectively). Conclusion: Crash site investigation and pelvic radiography may provide conflicting information about primary direction of injuring forces. Presumed anterior impact based on PDOF is not in consistent agreement with the pattern of injury evident on the AP pelvic radiograph.

Current Concepts in Imaging Evaluation of Penetrating Transmediastinal Injury

Penetrating transmediastinal injuries (TMIs) are injuries that traverse the mediastinum. These injuries are most commonly caused by firearms and knives. The investigation and management algorithms for TMI have undergone changes in recent years due to increasing evidence that computed tomography (CT) in useful in the evaluation of hemodynamically stable TMI patients. Initial investigation of TMI patients depends on the question of hemodynamic stability. In unstable patients, imaging (if any) should be limited to bedside radiography and focused ultrasonography. In hemodynamically stable patients in whom a mediastinal trajectory of injury is suspected, the primary imaging modality after radiography should be multidetector CT. CT is invaluable in the assessment of TMI due to its capacity to depict the injury track as well as demonstrate both direct and indirect signs of organ injury. On the basis of the suspected trajectory and specific findings, radiologists can play an essential role in determining future patient management and investigations for each mediastinal organ, thereby expediting appropriate investigation and treatment and avoiding unnecessary and sometimes invasive tests or surgery. The authors provide an up-to-date and evidence-based approach for the management of hemodynamically unstable and stable patients with suspected TMI, discuss management algorithms and CT protocols, and highlight common and uncommon imaging findings and diagnostic pitfalls associated with vascular, cardiac, esophageal, tracheobronchial, pleural, and pulmonary injuries. Online supplemental material is available for this article.

Imaging Foreign Bodies: Ingested, Aspirated, and Inserted.

Foreign bodies can gain entrance to the body through several mechanisms, ie, ingestion, aspiration, and purposeful insertion. For each of these common entry mechanisms, this article examines the epidemiology, clinical presentation, anatomic considerations, and key imaging characteristics associated with clinically relevant foreign bodies seen in the emergency department (ED) setting. We detail optimal use of multiple imaging techniques, including radiography, ultrasonography, fluoroscopy, and computed tomography to evaluate foreign bodies and their associated complications. Important imaging and clinical features of foreign bodies that can alter clinical management or may necessitate emergency intervention are discussed.

Blunt Urinary Bladder Trauma

A 29-year-old man was ejected from a car in a high-speed motor-vehicle crash without loss of consciousness. Upon arrival at Harborview Medical Center (HMC) he complained of neck and lower abdominal pain. Per HMC trauma protocol, he underwent a standard radiograph trauma series (anteroposterior chest radiograph, lateral view of the cervical spine, and anteroposterior view of the pelvis), which showed multiple fractures of the cervical spine. Physical examination demonstrated gross hematuria. The patient was stable and was sent for computed tomography (CT) angiography of the chest and neck followed by a venous phase scan of the abdomen and pelvis. Cervical CT confirmed multiple unstable factures of the cervical spine, cord compression, and a left vertebral artery stretch injury. A small amount of low-density fluid in the pelvis was the only abnormality noted at abdominal and pelvic CT (Fig 1). This prompted further investigation with CT cystography, which showed a superior bladder wall tear with intraperitoneal rupture and contrast/urine extravasation throughout the peritoneal cavity (Fig 2). There was no evidence of extraperitoneal bladder rupture. The patient underwent a cystorrhaphy with a favorable outcome. Bladder ruptures are rare. Eighty-three percent of patients with bladder rupture have pelvic fractures, but less than 10% of patients with pelvic fractures have bladder ruptures. 1,2 Bladder injuries are divided into