Computed radiography dose data mining and surveillance as an ongoing quality assurance improvement process.

OBJECTIVE: A data-mining program extracts computed radiography (CR) sensitivity-number (S-number) information from the PACS at our institution on a monthly basis as an ongoing quality assurance (QA) improvement project. These data are compared with the previous month's data and departmental S-number goals. The results are presented at monthly QA meetings. The S-number trends are then used by technologists to modify radiographic technique charts to reach the departmental S-number target range goals. CONCLUSION: This cyclic QA improvement process shows that mining PACS data can be useful in reducing patient radiation dose and interexamination dose variance.

Diagnosis and treatment of craniocervical dislocation in a series of 17 consecutive survivors during an 8-year period.

OBJECT: Craniocervical dissociation (CCD) is a highly unstable and usually fatal injury resulting from osseoligamentous disruption between the occiput and C-2. The purpose of this study was to elucidate systematic factors associated with delays in diagnosing and treating this life-threatening condition and to introduce an injury-severity classification with therapeutic implications. METHODS: In a retrospective evaluation of institutional databases, the authors reviewed medical records and original images obtained in 17 consecutive surviving patients with CCD treated between 1994 and 2002. Images and clinical results of treatment were evaluated, emphasizing the timing of diagnosis, clinical effect of delayed diagnosis, potential clinical or imaging warning signs, and response to treatment. Craniocervical dissociation was identified or suspected on the initial lateral cervical spine radiograph acquired in two patients (12%) and was diagnosed based on screening computerized tomography findings in two additional patients (12%). A retrospective review of initial lateral x-ray films showed an abnormal dens-basion interval in 16 patients (94%). The 2-day average delay in diagnosis was associated with profound neurological deterioration in five patients (29%). Neurological status declined in one patient after a fixation procedure was performed. There were no cases of craniocervical pseudarthrosis or hardware failure during a mean 26-month follow-up period. The mean American Spinal Injury Association (ASIA) motor score of 50 improved to 79, and the number of patients with useful motor function (ASIA Grade D or E) increased from seven (41%) preoperatively to 13 (76%) postoperatively. CONCLUSIONS: The diagnosis of CCD was frequently delayed, and the delay was associated with an increased likelihood of neurological deterioration. Early diagnosis and spinal stabilization protected against worsening spinal cord injury.

Severe posttraumatic craniocervical instability in the very young patient. Report of three cases.

Children younger than 3 years of age represent a distinct subpopulation of patients at particular risk for high cervical and craniovertebral injuries. There are few descriptions of survivors of severe craniocervical trauma among the very young, and scarce data exist regarding management after initial emergency stabilization. The authors describe three children, age 1 to 32 months, who presented with craniocervical junction injuries. Variable neurological findings were observed at presentation (cranial nerve deficits, obtundation, and moderate-to-severe quadriparesis). All three were treated with prolonged immobilization and have recovered with minimal to no neurological deficit.

Cerebral infarct in head injury: relationship to child abuse.

BACKGROUND: To determine whether CT-detected cerebral infarct in young children is associated more often with abuse or unintentional head injury. METHODS: Retrospective case-control study of injured children under age 6 who had abnormal initial head CT scans and who were admitted to the only Level I pediatric trauma center in Washington State for closed head injury (CHI) from January 1, 1992 to December 31, 1998. RESULTS: Fifteen children developed cerebral infarct after CHI during the 7 year period. These cases were compared to 53 controls (those who did not develop infarct). After adjusting for the presence of SDH and for severity of injury, patients with infarcts were six times more likely to have been abused than patients without infarcts (OR 6.1; 95% CI, 1.02-36.0). CONCLUSIONS: Cerebral infarct after CHI appears to result more frequently from abuse than unintentional injury in young children.

Color and pulsed Doppler sonography for arterial bleeding detection.

OBJECTIVE: Hemorrhage resulting from penetrating injuries in the extremities is the leading cause of preventable death in the modern battlefield. Development of methods for detection and localization of vascular bleeding is needed that could be applied emergently without special training outside the hospital setting. Our objective was to assess whether Doppler sonography can provide quantitative parameters that characterize the bleeding site in the extremities. METHODS: Twenty-four rabbit femoral arteries (diameter of approximately 1 mm) were punctured transcutaneously with an 18-gauge needle. Doppler interrogations were performed at 5 locations in the injured vessels (site of injury, distal and proximal locations relative to the injury, and neck and tip of the bleeding jet). RESULTS: Compared with the normal signals obtained before the vessel was punctured, pulsed Doppler observations of the injury site showed a statistically significant increase in the systolic and diastolic velocities (systolic: mean +/- SD, 30.1 +/- 12.5 cm/s [injury] versus 15.1 +/- 4.2 cm/s [normal]; diastolic: 17.8 +/- 6.5 cm/s [injury] versus 0.7 cm/s [normal]). Similar increases in velocities were observed at the neck of the bleeding jet, whereas the tip of the bleeding jet showed venouslike patterns. These patterns are unique only at the bleeding site. Color Doppler observations showed turbulence (in the form of checkered color patterns) localized at the injury site. CONCLUSIONS: Our results indicate that both color and pulsed Doppler sonography can be used to accurately localize the site of injury, which may facilitate application of hemorrhage control therapies in battlefield situations.

Diagnostic errors in polytrauma: a structured review of the recent literature.

Clinically important diagnostic errors are relatively common among polytrauma patients (2-40%). Errors are not random; they are more frequent in the spine and periarticular appendicular skeleton, especially in hemodynamically unstable patients who require resuscitation or operative intervention before completion of secondary or tertiary clinical survey. Misleading history, distracting findings, and misjudgments all contribute to risks of diagnostic errors.

Cervical spine fractures in patients 65 years and older: a clinical prediction rule for blunt trauma.

PURPOSE: To determine clinical predictors of cervical spine fracture in the elderly and to develop a clinical prediction rule to guide appropriate imaging in high-risk patients. MATERIALS AND METHODS: Institutional review board approval was received with waiver of informed consent. A retrospective case-control study was performed on blunt trauma patients 65 years and older with cervical spine fractures and on randomly selected control subjects without fracture. Potential predictors of fracture were evaluated through simple and multivariate logistic regression. Simple predictors were grouped into clinically similar composite variables and were analyzed with multivariate logistic regression and recursive partitioning. A clinical prediction rule was generated. The receiver operating characteristic curve was calculated and adjusted through bootstrap validation. Absolute cervical spine fracture probabilities were calculated by using Bayes theorem for all elderly patients and for patients who underwent computed tomography. Results were compared with a previous prediction rule for all adults. RESULTS: Composite predictors of fracture in the elderly included focal neurologic deficit (adjusted odds ratio, 17.7; 95% confidence interval [CI]: 3.8, 83.4), severe head injury (odds ratio, 3.2; 95% CI: 1.5, 7.1), high-energy mechanism (odds ratio 6.7; 95% CI: 3.1, 14.8), and moderate-energy mechanism (odds ratio 3.3; 95% CI: 1.3, 8.3). The prediction rule stratified patients into risk groups with fracture probabilities ranging from 0.4% (95% CI: 0.1%, 1.3%) to 24.2% (95% CI: 5.7%, 100%). CONCLUSION: Clinical factors can be used to stratify patients 65 years and older into risk groups with a wide range of probabilities of cervical spine fracture. Knowledge of cervical fracture risk can help guide appropriate imaging in high-risk patients.

Physician assistants in academic radiology: the Harborview experience.

We describe a model of how physician assistants can be used in an academic medical center to expand radiologist productivity, and to enhance the departmental academic and educational missions. At Harborview Medical Center, following a training program and graduated responsibility under supervision, physician assistants provide initial interpretation of radiology studies, consultation to referring physicians, and perform less complicated interventional procedures. Acceptance of physician assistants by the radiologists, radiology residents, and referring physicians has been high. Although the impact of physician assistants on departmental clinical productivity is difficult to measure, our data suggest that radiologists are more efficient when physician assistants are assigned to service, both in terms of numbers of studies interpreted, and timeliness of reporting and billing. As a result of the success of our program, we believe that physician assistants can have an important role in radiology practice.

Anatomic and radiographic considerations for placement of transiliac screws in lumbopelvic fixations.

Lumbopelvic fixation in spinal and pelvic surgery relies on rods or screws as an iliac anchor. Secure placement of screws with maximum diameter and length for the greatest pullout strength requires knowledge of the iliac structure and of intraoperative fluoroscopic landmarks for secure placement. Therefore, the authors evaluated the intrailiac length, inner width, and cortical thickness of three different transiliac screw anchor paths aimed toward the anterior inferior iliac spine and initiated at the iliac tubercle, posterior superior iliac spine, or posterior inferior iliac spine. Measurements were made using two- and three-dimensional computed tomographic reformations in 40 consecutive trauma patients (27 measurements in 21 males, 16 to 75 years old; 28 measurements in 19 females, 16 to 78 years old). In addition, fresh and dry human cadaveric specimens were marked with metal wires at the previously determined optimal screw path to determine fluoroscopic landmarks for easiest and best controlled transiliac screw placement. The posterior superior iliac spine-anterior inferior iliac spine path had the largest bony canal lengths, with 141 mm in male and 129 mm in female patients. Two stereotypic iliac constrictions allowed placement of 8-mm implants in male and 6- to 7-mm implants in female patients. Cortical thickness at that optimal extraarticular path was 5.2 mm in the male and 4.7 mm in the female patients. Transiliac screws can be placed during operation under fluoroscopic control using standard lateral and obturator oblique-outlet views, the latter presenting a stereotypical teardrop figure above the acetabulum.

Trans-Atlantic hospital agreement in reading first day radiographs of clinically suspected scaphoid fractures.

The purpose of this study was to describe the agreement between two hospitals on either side of the Atlantic Ocean in reading first day plain radiographs of suspected scaphoid fractures. Two groups of observers, one North American and one European, consisting of observers at various levels of training were compared. Kappa statistics were used to determine inter- and intra-observer agreement. The receiver-operating characteristics (ROC) curves and area under this curve (AUC) for each observer were calculated to determine test performance. Scaphoid radiographs of 80 consecutive patients seen with clinically suspected scaphoid fracture were included in the study. The results of the bone scan were used as the reference standard. There is an acceptable agreement between the USA and Europe for both radiologists and orthopaedic surgeons at various levels of training (kappa 0.45-0.88). Intra-observer agreement is acceptable as well (kappa 0.46-0.86). Considering all normal or equivocal radiographs, there is slight to moderate agreement at all levels of training in and between both centres and specialities (kappa 0-0.64). Overall test performance was acceptable for all consecutive radiographs (AUC 0.65-0.82) and poor for the normal radiographs (AUC 0.46-0.65). We could not detect differences in performance due to location of the readers' hospital or institution of training. The use of more sensitive techniques should be restricted to patients with negative or equivocal radiographs in clinically suspected scaphoid fractures.

Can we rely on mediastinal widening on chest radiography to identify subjects with aortic injury?

Widening of the mediastinum on chest radiography is widely promoted as a useful criterion for detecting aortic injury. We sought to determine the reliability, sensitivity, and specificity of this sign. The initial chest radiographs from 30 subjects with aortic injury and 47 controls were independently reviewed by six radiologists, who were blinded to diagnosis. The radiologists were asked to decide whether the mediastinum was normal or not normal, as well as whether the mediastinum was widened. Agreement, sensitivity, and specificity were assessed. Agreement for overall assessment of the mediastinum was substantial (kappa = 0.64). Individual radiologists had sensitivity varying from 0.77 to 0.97 and specificity varying from 0.62 to 0.89. For "widening" of the mediastinum, agreement was moderate (kappa = 0.49). "Widening" was less sensitive than the radiologists' overall impression (P = 0.01), varying from 0.50 to 0.83, but no difference was detected in specificity (P = 0.36), varying from 0.81 to 0.94. Mediastinal width has unacceptable sensitivity for predicting aortic injury, with substantial inter-reader variability. Medical education has ingrained the widely promoted concept of mediastinum widening, which may be misleading.

Four-channel multidetector CT in facial fractures: do we need 2 x 0.5 mm collimation?

OBJECTIVE: Our aim was to optimize acquisition protocols and multiplanar reformation algorithms for the evaluation of facial fractures using multidetector CT (MDCT) and to determine whether 2 x 0.5 mm collimation is necessary. MATERIALS AND METHODS: A cadaveric head with artificial blunt facial trauma was examined using a four-channel MDCT scanner. The influence of acquisition parameters (collimation, 2 x 0.5 mm, 4 x 1 mm, 4 x 2.5 mm; tube current, 120 mAs, 90 mAs, 60 mAs), image reconstruction algorithms (standard vs ultra-high-resolution modes; reconstructed slice thicknesses, 0.5 mm, 1 mm, 3 mm; increment, 0.3 mm, 0.6 mm, 1.5 mm), and reformation algorithms (slice thicknesses, 0.5 mm, 1 mm, 3 mm; overlap, 0.5 mm, 1 mm, 3 mm) on detectability of facial fractures in multiplanar reformations with MDCT was analyzed. RESULTS: Fracture detection was significantly higher with thin multiplanar reformations (0.5 and 0.5 mm, 1 and 0.5 mm, and 1 and 1 mm) (p < or = 0.014) acquired with 2 x 0.5 mm collimation (p < or = 0.046) in ultra-high-resolution mode (p < 0.0005) with 120 mAs (p < or = 0.025). Interobserver variability showed very good agreement (kappa > or = 0.942). Non-ultra-high-resolution mode, lower milliampere-seconds, and thick multiplanar reformations (3 and 0.5 mm, 3 and 1 mm, and 3 and 0.5 mm) showed significantly decreased fracture detectability. CONCLUSION: Although thin multiplanar reformations obtained from thin collimation (2 x 0.5 mm) are statistically superior for the detection of subtle fractures, 4 x 1 mm collimation is sufficient for routine diagnostic evaluation. Ultra-high-resolution mode with 120 mAs is mandatory for detection of clinically relevant fractures.

Atypical focal nodular hyperplasia of the liver: imaging features of nonspecific and liver-specific MR contrast agents.

OBJECTIVE: The objective of our study was to describe the functional and differential uptake features of atypical focal nodular hyperplasia using different MR contrast agents and to evaluate their potential role in the diagnosis and characterization of focal nodular hyperplasia. MATERIALS AND METHODS: Contrast-enhanced MR images of 45 patients with 85 focal nodular hyperplasia lesions were retrospectively reviewed. In these patients, sonographic findings were nonspecific (n = 37), or CT features were inconclusive (n = 8). Non-liver specific gadolinium chelates were used in 18 patients (48 lesions) suspected of having either focal nodular hyperplasia or hemangioma. The following liver-specific agents were used in patients with suspected focal nodular hyperplasia or metastases: mangafodipir trisodium, 30 patients (55 lesions); ferumoxides, six patients (16 lesions); and SHU 555 A, six patients (six lesions). Individual lesions were quantified by signal intensity and assessed qualitatively by homogeneity, contrast enhancement, and presence of a central scar. RESULTS: At unenhanced MR imaging, the triad of homogeneity, isointensity, and central scar was found in 22% of the focal nodular hyperplasia lesions. On mangafodipir trisodium-enhanced T1-weighted images, all focal nodular hyperplasia lesions showed contrast uptake: in 64% of the lesions, uptake was equal to parenchyma; 25%, greater than the parenchyma; and 11%, less than the parenchyma. On iron oxide-enhanced T2-weighted images, all focal nodular hyperplasia lesions showed uptake of the contrast agent, but contrast uptake in the lesions was less than in the surrounding parenchyma. Dynamic gadolinium chelate-enhanced MR imaging showed early and vigorous enhancement of focal nodular hyperplasia lesions with rapid washout in 88%. Atypical imaging features of the lesions included hyperintensity on T1-weighted images, necrosis and hemorrhage, and inhomogeneous or only minimal contrast uptake. CONCLUSION: For patients in whom the diagnosis of focal nodular hyperplasia cannot be established on unenhanced or gadolinium-enhanced MR imaging, homogeneous uptake of liver-specific contrast agent with better delineation of central scar may help to make a confident diagnosis of focal nodular hyperplasia.