Accuracy of craniocervical measurements on CT for identifying partial or complete craniocervical ligament injuries in pediatric patients

PURPOSE

To assess the accuracy of craniocervical measurements for identifying craniocervical injuries and the frequency of subjective findings of craniocervical injuries on CT in pediatric patients.

METHODS

Case-controlled retrospective review of patients ≤ 16 years old with craniocervical junction injuries. Receiver operator curves were created for common craniocervical measurements on CT comparing patients with complete and partial craniocervical injuries to uninjured cohort. Frequency of subjective CT findings of craniocervical injury was assessed in the injured cohort.

RESULTS

For complete disruption injuries (CD) (n = 27), C1-C2 distance (AUC = 0.90, 95%CI = 0.83-0.97), atlanto-occipital distance (AUC = 0.95-0.98, 95%CI = 0.90-1.00), and basion-dens distance (AUC = 0.90, 95%CI = 0.82-0.98) had excellent accuracy diagnosing injury. Powers ratio (AUC = 0.85, 95%CI = 0.76-0.94) had good, basion-posterior axial line (AUC = 0.74, 95%CI = 0.61-0.86) fair, and atlanto-dental distance (AUC = 0.69, 95%CI = 0.57-0.82) poor accuracy. For partial disruption injuries (PD) (n = 21), basion-dens distance (AUC = 0.75, 95%CI = 0.62-0.88) had fair accuracy diagnosing injury. Powers ratio (AUC = 0.63, 95%CI = 0.47-0.79), C1-C2 distance (AUC = 0.60, 95%CI = 0.45-0.75), atlanto-dental distance (AUC = 0.55, 95%CI = 0.39 = 0.71), atlanto-occipital distance (AUC = 0.63-0.65, 95%CI = 0.47-0.81), and basion-posterior axial line (AUC = 0.60, 95%CI = 0.44-0.76) all had poor accuracy. Eighty-one percent (n = 22) of CD and 38% (n = 8) of PD patients had non-concentric atlanto-occipital joints. One hundred percent of CD patients had ≥ 1 soft tissue finding and eighty-one percent (n = 22) had ≥ 2 findings. Seventy-three percent (n = 16) of PD patients had ≥ 1 soft tissue finding. Eighty-six percent (n = 18) of PD patients had non-concentric atlanto-occipital joints and/or soft tissue findings.

CONCLUSION

Craniocervical measurements have poor accuracy for identifying craniocervical injuries in pediatric patients with incomplete craniocervical ligament disruption. Subjective findings of craniocervical injury are frequently present on CT in pediatric patients and can help increase sensitivity for identifying injury.

ACR Appropriateness Criteria® Major Blunt Trauma

This review assesses the appropriateness of various imaging studies for adult major blunt trauma or polytrauma in the acute setting. Trauma is the leading cause of mortality for people in the United States <45 years of age, and the fourth leading cause of death overall. Imaging, in particular CT, plays a critical role in the management of these patients, and a number of indications are discussed in this publication, including patients who are hemodynamically stable or unstable; patients with additional injuries to the face, extremities, chest, bowel, or urinary system; and pregnant patients. Excluded from consideration in this review are penetrating traumatic injuries, burns, and injuries to pediatric patients. Patients with suspected injury to the head and spine are also discussed more specifically in other appropriateness criteria documents. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Incidence of cervical spine fractures on CT: a study in a large level I trauma center

INTRODUCTION/PURPOSE

Though spinal fractures constitute a minority of all traumas, the financial burden imposed is immense especially following cervical spine trauma. There have been several papers in the past describing the incidence of cervical spine fractures. In this paper, we report the incidence of cervical spine fractures and correlate with demographic information and cause of injury and review the mechanism of fractures.

MATERIALS AND METHODS

We performed retrospective analysis of 934 patients who had undergone CT scan for cervical spine trauma at our institute which includes 16 hospitals and one level I trauma center over a period of 2 years. This list was created from a wider database of 13,512 patients imaged for suspected cervical spine injury. All patients who had at least one positive finding on CT were included in this study irrespective of any demographic difference. Each patient was analyzed by reviewing the medical records, and correlation was sought between demographics and cause of injury.

RESULTS

In our study, the peak incidence of cervical spine trauma was in the age group of 21-30 years followed by 31-40 years with a male:female ratio of 2.1. The major cause of injury in the study population was motor vehicle accidents (66.1%), followed by fall from height of less than 8 ft (12.2%). With regard to the ethnic distribution, Caucasians (46.9%) constituted the major population followed by Hispanic population (23.3%). C1 and C2 were observed to be more frequently fractured as compared with the subaxial spine. Incidence of C2 fractures (188 levels) was higher as compared with C1 (102 levels). Incidence of body and lateral mass fractures was marginally higher as compared with odontoid fractures. C7 (50 levels) was the most fractured vertebral body in the subaxial spine followed by C6 (35 levels) and C5.

CONCLUSION

Spinal trauma is on the rise and it helps to know the factors which can guide us for better management of these patients. We can utilize these results to prognosticate and streamline clinical management of these patients.

Imaging of Traumatic Shoulder Girdle Injuries

Shoulder girdle trauma is one of the most common injuries encountered in emergency centers. These injuries can be easily overlooked due to the complex osteology of the shoulder. Although radiographs are usually sufficient for assessing traumatic shoulder injuries, cross-sectional imaging is sometimes indicated to assess portions of the shoulder not well visualized by radiographs. In this article, the authors review the spectrum of shoulder girdle injuries: sternoclavicular dislocations, clavicle fractures, acromioclavicular separations, shoulder dislocations, scapula fractures, and scapulothoracic dissociation. They also discuss the presentation, imaging evaluation, and classification of these injuries with emphasis on pitfalls in imaging diagnosis and indications for computed tomography/magnetic resonance.

Is elevated body mass index protective against cervical spine injury in adults?

PURPOSE

Correlate body mass index (BMI) with incidence and type of cervical spine injury seen on CT in adult patients presenting with blunt trauma.

MATERIALS AND METHODS

Retrospective chart review of all adult blunt trauma patients who had a cervical spine CT performed at our level 1 trauma center during an approximately 3-year period.

RESULTS

A statistically significant (p = 0.01) difference in cervical spine injury incidence was present between different BMI groups. Cervical spine injury incidence was 7.7% for underweight (BMI ≤ 18) patients, 7.1% for normal weight (BMI 18-25) patients, 6.2% for overweight/obese (BMI 25-35) patients, and 4.7% for morbidly obese (BMI > 35) patients. Using BMI > 18-25 as a reference group, females with BMI > 25-35 had an adjusted odds ratio (aOR) of 0.56 (CI 0.41-0.75) and females with BMI > 35 had an aOR of 0.42 (CI 0.26-0.70). Males with a BMI ≤ 18 had an aOR of 2.20 (CI 1.12-4.32) and males with BMI > 35 had an aOR of 0.66 (CI 0.46-0.95). A particularly low incidence of cervical spine injury was observed in patients older than 65 in the obese group with a cervical spine injury rate of only 1.4% in this patient population. No statistical significant difference was seen in injury morphology across the BMI groups.

CONCLUSION

An inverse relationship exists between BMI and the overall incidence of cervical spine injury. This protective effect appears to be influenced by gender with elevated BMI having lower relative odds of cervical spine injury in women than in men. A particularly low rate of cervical spine injury was identified in obese patients over the age of 65. Routine imaging of all elderly, obese trauma patients with low energy mechanism of injury may not be warranted.

ACR Appropriateness Criteria Head Trauma

Neuroimaging plays an important role in the management of head trauma. Several guidelines have been published for identifying which patients can avoid neuroimaging. Noncontrast head CT is the most appropriate initial examination in patients with minor or mild acute closed head injury who require neuroimaging as well as patients with moderate to severe acute closed head injury. In short-term follow-up neuroimaging of acute traumatic brain injury, CT and MRI may have complementary roles. In subacute to chronic traumatic brain injury, MRI is the most appropriate initial examination, though CT may have a complementary role in select circumstances. Advanced neuroimaging techniques are areas of active research but are not considered routine clinical practice at this time. In suspected intracranial vascular injury, CT angiography or venography or MR angiography or venography is the most appropriate imaging study. In suspected posttraumatic cerebrospinal fluid leak, high-resolution noncontrast skull base CT is the most appropriate initial imaging study to identify the source, with cisternography reserved for problem solving. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every three years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

ACR Appropriateness Criteria Myelopathy

Patients presenting with myelopathic symptoms may have a number of causative intradural and extradural etiologies, including disc degenerative diseases, spinal masses, infectious or inflammatory processes, vascular compromise, and vertebral fracture. Patients may present acutely or insidiously and may progress toward long-term paralysis if not treated promptly and effectively. Noncontrast CT is the most appropriate first examination in acute trauma cases to diagnose vertebral fracture as the cause of acute myelopathy. In most nontraumatic cases, MRI is the modality of choice to evaluate the location, severity, and causative etiology of spinal cord myelopathy, and predicts which patients may benefit from surgery. Myelopathy from spinal stenosis and spinal osteoarthritis is best confirmed without MRI intravenous contrast. Many other myelopathic conditions are more easily visualized after contrast administration. Imaging performed should be limited to the appropriate spinal levels, based on history, physical examination, and clinical judgment. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every three years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals, and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

Multidetector CT evaluation of active extravasation in blunt abdominal and pelvic trauma patients

Timely localization of a bleeding source can improve the efficacy of trauma management, and improvements in the technology of computed tomography (CT) have expedited the work-up of the traumatized patient. The classic pattern of active extravasation (ie, administered contrast agent that has escaped from injured arteries, veins, or urinary tract) at dual phase CT is a jet or focal area of hyperattenuation within a hematoma that fades into an enlarged, enhanced hematoma on delayed images. This finding indicates significant bleeding and must be quickly communicated to the clinician, since potentially lifesaving surgical or endovascular repair may be necessary. Active extravasation can be associated with other injuries to arteries, such as a hematoma or a pseudoaneurysm. Both active extravasation and pseudoaneurysm (unlike bone fragments and dense foreign bodies) change in appearance on delayed images, compared with their characteristics on arterial images. Other clues to the location of vessel injury include lack of vascular enhancement (caused by occlusion or spasm), vessel irregularity, size change (such as occurs with pseudoaneurysm), and an intimal flap (which signifies dissection). The sentinel clot sign is an important clue for locating the bleeding source when other more localizing findings of vessel injury are not present. Timely diagnosis, differentiation of vascular injuries from other findings of trauma, signs of depleted intravascular volume, and localization of vascular injury are important to convey to interventional radiologists or surgeons to improve trauma management.

Mathematical modeling improves computed tomography diagnosis of traumatic aortic injury

RATIONALE AND OBJECTIVES

Acute traumatic aorta injuries (ATAIs) following blunt thoracic trauma require rapid and accurate diagnosis for institution of lifesaving treatment. The use of computed tomography (CT) in the diagnosis of such injuries continues to improve and has the potential to become the diagnostic modality of choice in many trauma centers. A standardized diagnostic model may contribute to improvements in radiologist interpretation of CT for ATAIs.

MATERIALS AND METHODS

The following diagnostic criteria were used to develop a diagnostic model for ATAIs: 11 areas of potential hematoma formation were identified in the mediastinum. Maximum short- and long-axis cross-sectional diameters of the aorta were measured. Qualitative morphologic information (contour change, intimal flap) was recorded. Smoothness of the aorta wall was assessed. These characteristics were quantified and analyzed for statistical significance, allowing for the development of an injury assessment model.

RESULTS

The diagnostic model was used to score 69 blunt thoracic trauma patient cases. Average weighted kappa was 0.74, showing strong agreement among two observers and reproducibility of the model. The model improved injury assessment by classifying equivocal cases as either positive or negative. The ROC curve calculated from the original radiologist interpretation contained 86.1% area under the curve, while the curve for the new model contained 97.5%. The likelihood ratio increased from 30.06 to 48.67. The degree to which the new measure improved prediction over the original radiologist reading was tested using a nested model and yielded a reliable increment in model fit (chi2 analysis: Deltachi2(3) = 20.929, P < or = .0001). Finally, beta weights calculated from each variable were used to create a quantitative best-fit diagnostic model for future use.

CONCLUSION

We have developed a diagnostic tool that may help radiologists better evaluate CT for ATAIs.

CT of nontraumatic thoracic aortic emergencies

Computed tomography (CT), especially multidetector row CT (MDCT), is often the preferred imaging test used for evaluation of nontraumatic thoracic aortic abnormalities. Unenhanced images, usually followed by contrast-enhanced arterial imaging, allow for rapid detailed aortic assessment. Understanding the spectrum of acute thoracic aortic conditions which may present similarly (aortic dissection, aneurysm rupture, penetrating atherosclerotic ulcer, intramural hematoma) will ensure that patients are diagnosed and treated appropriately. Familiarity with imaging protocols and potential mimics will prevent confusion of normal anatomy and variants with aortic disease.

Diagnosing Traumatic Arterial Injury in the Extremities with CT Angiography: Pearls and Pitfalls

Computed tomographic (CT) angiography is a reliable and convenient imaging modality for diagnosing arterial injuries after blunt and penetrating trauma to the extremities. It is a noninvasive modality that could replace conventional arteriography as the initial diagnostic study for arterial injuries after trauma to the extremities. The technique requires scanning with multidetector helical CT after rapid intravenous injection of iodinated contrast material. The CT angiographic signs of arterial injuries in the extremities are active extravasation of contrast material, pseudoaneurysm formation, abrupt narrowing of an artery, loss of opacification of a segment of artery, and arteriovenous fistula formation. Metallic streak artifact, motion artifact, and inadequate arterial opacification may render a CT angiogram nondiagnostic. Studies have shown the sensitivity of CT angiography to be 90%-95.1% and its specificity 98.7%-100% for detecting arterial injury to the extremities after trauma.

How to image from head to pubis for blunt abdominal trauma using GE LightSpeed QX/i

Multislice CT scanners can rapidly produce head-to-pubis images in multitrauma patients. This article summarizes the technical advances that distinguish multislice CT scanners from single-slice helical CT scanners. It is important to understand certain physical principles in order to use this powerful technology to maximum diagnostic advantage while keeping radiation doses at reasonable levels. The CT imaging protocol of our institution is presented along with a discussion of the rationale behind our protocol choices. One of the important advantages in using the total body CT approach is its ability to perform CT angiography of the aorta and multiplanar reformatted images of the spine from a single pass through the torso. Techniques for optimizing reformatted images conclude the article.

Genetic studies in familial ankylosing spondylitis susceptibility

OBJECTIVE

To define the genetic basis of susceptibility to ankylosing spondylitis (AS), especially non-major histocompatibility complex (MHC) genes.

METHODS

The study group comprised 244 affected sibling pairs from 180 pedigrees of primarily European ancestry. Sibling pairs were concordant for AS by the modified New York criteria and had available sacroiliac radiographs. The subjects were genotyped for 400 markers in ABI PRISM linkage map MD-10 and for 17 additional markers on chromosomes 6p, 6q, and 11q (including HLA-B, DRB1, DQA1, DQB1, and DPB1 alleles). Two-point and multipoint nonparametric linkage (NPL) analyses were conducted using the NPL statistic and 1-parameter allele-sharing model logarithm of odds (LOD) scores, calculated using the Allele-Sharing Model (ASM) computer program.

RESULTS

Linkage of the MHC region was supported by both 2-point and multipoint analyses, with the strongest peak (45.90 cM) in the MHC at the HLA-DRB1 locus (NPL score 8.720, ASM LOD score 20.49; P = 6.8 x 10(-20) for 2-point analysis). A second region was found to have positive linkage at the q arm of chromosome 6 (D6S441) in 2-point analysis; this was supported by a 39.13-cM region (135.58-174.71 cM) in multipoint analysis, with the smallest P value (4.2 x 10(-3)) at 166.39 cM. A third region was found on chromosome 11q, with the strongest evidence for linkage for D11S4094 at 123 cM (NPL score 2.235, ASM LOD score 1.939) and, on transmission disequilibrium test analysis, D11S4090 at 105.74 cM (P = 6.2 x 10(-5)). Linkage in this area was supported by multipoint analysis, spanning 22.19 cM continuously from 101.68 cM to 123.87 cM, with the strongest peak at 112.33 cM (P = 0.014); this was confirmed by subsequent fine mapping studies.

CONCLUSION

Thus, this genome-wide scan implicates, in addition to the MHC, regions outside the MHC in AS susceptibility, especially on chromosomes 6q and 11q.

Palmar dislocation of the trapezoid

Palmar dislocation of the trapezoid is a rare injury, which results from substantial trauma to the wrist. It is associated with other bony or ligamentous injuries in the wrist. If unrecognized, loss of function of the hand and early osteoarthritis may result. Treatment of choice is open reduction and internal fixation, which generally achieves good functional results. We describe a new case of palmar dislocation of the trapezoid and review the world literature with emphasis on the radiographic findings.

Patterns of diagnostic error in trauma abdominal CT

OBJECTIVE

To define patterns of diagnostic error in the interpretation of trauma abdominal CT.

MATERIALS AND METHODS

Two hundred fifty-four out of 1751 abdominal CT scans performed for evaluation of trauma had a definite or equivocal diagnosis of an abdominal injury. Cases were re-read initially without reference to the original reports, in which 44 potential diagnostic errors were identified. A panel of two or three expert readers reviewed each of the 44 cases along with the original report to evaluate the diagnostic error and to search for patterns among the errors.

RESULTS

Thirty-one of the 254 CT scans (12%) that were re-read contained non-trivial mistakes that could affect patient outcome. Seventeen were false negative and 14 were false positive. Diagnostic errors were found in the liver, spleen, kidney, retroperitoneum, and peritoneal cavity. Patterns of false-negative diagnosis included missed vascular contrast extravasation, missed hemoperitoneum, and missed right retroperitoneal hematoma. Patterns of false-positive diagnosis included: periportal edema or blood tracking, called a liver laceration; respiratory motion, called a splenic or renal injury; and linear or round lucencies in the spleen or liver, called a laceration.

CONCLUSION

Diagnostic errors in interpreting trauma abdominal CT cluster in several recurring patterns. Awareness of these patterns may assist readers in avoiding future errors.

Imaging evaluation of posttraumatic renal injuries

Computed tomography plays an important role for the evaluation of most patients with suspected renal injury after trauma. Intravenous urography is used for gross assessment of renal function in hemodynamically unstable patients. Renal injuries can be classified into four large groups: (1) minor renal contusion, lacerations, subcapsular hematoma, and small cortical infarcts; (2) major renal lacerations extending to the medulla with or without involvement of the collecting system; (3) catastrophic renal injuries including fragmentation of the kidney and renal pedicle vascular injuries; and (4) ureteropelvic junction injuries. Integration of the imaging findings of renal injury with clinical information is important to developing a treatment plan.

Imaging of renal trauma: a comprehensive review

Computed tomography (CT) is the modality of choice in the evaluation of blunt renal injury. Intravenous urography is used primarily for gross assessment of renal function in hemodynamically unstable patients. Selective renal arteriography or venography can provide detailed information regarding vascular injury. Retrograde pyelography is valuable in assessing ureteral and renal pelvic integrity in suspected ureteropelvic junction injury. Ultrasonography is useful in detecting hemoperitoneum in patients with suspected intraperitoneal injury but has limited value in evaluating those with suspected extraperitoneal injury. Occasionally, radionuclide renal scintigraphy or magnetic resonance imaging may prove helpful. Renal injuries can be classified into four large categories based on imaging findings. Category I renal injuries include minor cortical contusion, subcapsular hematoma, minor laceration with limited perinephric hematoma, and small cortical infarct. Category II lesions include major renal lacerations extending to the medulla with or without involvement of the collecting system and segmental renal infarct. Category III lesions are catastrophic renal injuries and include multiple renal lacerations and vascular injury involving the renal pedicle. Category IV injuries are ureteropelvic junction injuries. CT is particularly useful in evaluating traumatic injuries to kidneys with preexisting abnormalities and can help assess the extent of penetrating injuries in selected patients with limited posterior stab wounds. Integration of the imaging findings in renal injury with clinical information is critical in developing a treatment plan.

Screening helical CT for evaluation of blunt traumatic injury in the pregnant patient

Pregnant patients who sustain severe blunt trauma are infrequently encountered in most practices. However, detection of internal injuries including those to the gravid uterus is essential since maternal disability or fetal loss are physical and psychologic catastrophes that have long-term effects on the mother and her family. Computed tomography (CT) is commonly used to detect blunt traumatic injuries and can play an important role in the screening of the injured pregnant woman. The normal gravid uterus and physiologic changes of pregnancy can confound CT interpretation. Inhomogeneous enhancement of placental cotyledons, hydronephrosis, and enlarged ovarian veins are normal findings. Avascular regions in the placenta indicate infarction or abruption with impending fetal demise. Although CT can demonstrate uterine rupture and retroperitoneal hemorrhage, direct detection of fetal injuries is rare. Fetal demise is more common when maternal injuries include trauma to the uterus. Although screening ultrasonography can depict fetal distress, use of screening CT allows a concurrent evaluation of multiple areas in the pregnant trauma patient including the uterus. CT is a useful diagnostic tool in the triage of the critically injured pregnant woman.

Evaluating the impact of workstation usage on radiology report times in the initial 6 months following installation

Picture archiving and communications systems (PACS) workstations are reported to improve workflow by making studies immediately available for review upon their completion. This study tested the hypothesis that a workstation would decrease the time from completion of a study to dictation of results (report time). A four-monitor, 2K x 2K workstation (Imation Cemax-Icon, Fremont, CA), was installed in a body imaging computed tomography (CT) reading room. Use of the workstation by the staff radiologists was voluntary. Images were also printed on film and films continued to be hung at the routine hanging times. To evaluate the workstation's maximum impact, data were collected for report times for studies completed during the routine day shift of the staff radiologist (Monday to Friday, 8 AM to 5 PM). Data were collected before workstation installation (August 1997 to November 1997) and for the subsequent 6 months. Histograms of the number of studies (743 v 103) versus report time (mean, 11.7 v 7.4 hours) showed a bimodal distribution, with peaks at approximately 6 and 24 hours, both before (8/97-11/97) and after (6/98) the workstation's installation. However, the number of studies dictated greater than 60 hours (25.2% v 20.4%) and the percentage of studies in the second peak (16 to 48 hours; 4.4% v 0%) both decreased. In conclusion, the workstation decreased the mean (11.7 v 7.4 hours) and standard deviation (19.8 v 9.1 hours) for report times. This was due to a decrease in both the number of cases dictated the day following their completion and the number of outliers (markedly delayed dictations). The decrease in outliers is probably due to a decrease in the number of "lost" film-based studies.

Syndesmotic ankle injuries in rodeo bull riders

This report describes five male rodeo bull riders, aged 18 to 32 years, who sustained syndesmotic ankle injuries during competition. The mechanism of injury was identical in each case. As the rider attempted to escape after being thrown, the bull stepped on his lateral ankle, resulting in forced external rotation. All patients delayed seeking medical care, the interval between the injury and presentation ranging from 2 days to 4 weeks. All five patients sustained significant syndesmotic tears, two with associated fibular fractures. Three patients underwent surgical stabilization, and all riders returned to competitive rodeo events, often prior to medical clearance. To the authors' knowledge, this is the first reported association between injuries caused by livestock stepping and syndesmotic disruptions.

Acute cervical spine trauma: diagnostic performance of single-view versus three-view radiographic screening

PURPOSE

To compare the diagnostic accuracy of single-view and three-view cervical spine radiographs in acute trauma.

MATERIALS AND METHODS

Radiographs of 97 patients with acute cervical spine fractures were matched with those of 92 proved normal cases. Fourteen radiologists, including three senior attending radiologists each with more than 20 years of post-residency experience, four junior attending radiologists each with less than 5 years of practice experience, three senior radiology residents in their 3rd or 4th year of radiology residency, and four junior radiology residents at the end of their 1st year of radiology training, interpreted each case twice: once as a lateral-only study and again as a three-view study. Multireader-multicase receiver operating characteristic analysis was performed. Difficult cases were reviewed for trends in the errors.

RESULTS

Eight of 14 readers detected fractures better with the three-view series. Among junior attending radiologists, the differences were statistically significant. Most improvements were in fractures of the dens and fractures and unilateral dislocations of the articular mass. Overall, sensitivity increased from 81.8% to 83.3%. The reliability of fracture classification improved. Less experienced readers performed better with the three-view series.

CONCLUSION

A three-view screening radiographic series will allow most readers to detect a few more fractures than a single-view series. The improvements occur primarily in a subset of difficult-to-diagnose injuries.

Do wrist guards protect against fractures?

STUDY OBJECTIVE

To determine whether wrist guards increase the fracture threshold for wrist and forearm fractures.

METHODS

We conducted a controlled, blinded experimental study using matched cadaveric arms-one fitted with a wrist guard-dropped with the use of a device designed to simulate a fall. We measured the mean number of drops before the occurrence of fracture, mean height and velocity change to fracture, mean kinetic energy, mean peak acceleration (in Gs), and summed impulse [weight (kilograms) x delta velocity (meters/second)] to fracture with and without wrist guards. Fracture severity was compared with the use of an ordinal ranking system and analyzed with the Mann-Whitney rank-sum test.

RESULTS

Wrist guards were associated with a statistically significant increase in the number of drops, mean drop height, mean kinetic energy, and summed impulse required to cause a fracture. Fractures also tended to be less severe when wrist guards were used.

CONCLUSION

The biomechanical evidence of a protective effect of wrist guards against wrist fractures seen in this study, coupled with previous epidemiologic evidence, is strong enough to warrant pediatricians, family practitioners, and emergency physicians to counsel skaters to use these devices when using roller skates, skateboards, or in-line skates.

Vertical fracture of the central sacral canal: plane and simple

A case is reported of a sagittal fracture of the sacrum associated with diastasis of the symphysis pubis. The patient suffered no lasting neurologic injury. A literature review suggests that these vertical fractures may carry a better prognosis than other sacral fractures that involve the central canal.

Diagnostic performance of CT, MPR and 3DCT imaging in maxillofacial trauma

CT imaging of complex maxillofacial fractures is common practice now, but the relative diagnostic value of spiral computed tomography (CT), multiplanar reformations (MPR), and three-dimensional (3D) reconstructions in evaluating maxillofacial fractures is not established with independent validation of correct diagnosis. We studied these modalities and measured their diagnostic value in a carefully controlled observer based rated response experiment. Multiple fractures were created by blunt experimental trauma in nine adult cadaver heads (five males, four females). Spiral CT scans were performed on all specimens before (control) and after trauma. Axial slices (CT), sagittal and coronal multiplanar reconstructions (MPR), and 3D volumetric reconstructions views were generated. Truth was determined by defleshing the specimens and direct inspection of the traumatized skull. Three expert readers separately interpreted CT, MPR and 3D film hard copy images presented in random order blinded to patient identification or experimental conditions. We measured the time to diagnose each case as recorded by a monitor who was present while evaluations were performed. Twenty-eight facial regions were evaluated using rated response and free response illustrative formats. Each region was considered separately. Sensitivity and specificity were calculated to measure observer performance. We found that 3D and CT had a similar performance in fracture detection and both were markedly better than MPR. For free response illustrative data, CT correctly identified 10% more orbital fractures than 3D, and approximately 10% fewer zygomatic fractures. Fracture localization was best with 3D. Reader confidence was highest with CT, but assessment time was faster with 3D. We conclude that CT and 3D are comparable in detecting midfacial fractures and both are superior to MPR. 3D reconstructions are superior for localization of complex fractures involving multiple planes.

Quantitative analysis of the plain radiographic appearance of central chondrosarcoma of bone

RATIONALE AND OBJECTIVE

To quantitate radiographic features that distinguish the plain radiographic appearance of central chondrosarcoma from other solitary bone lesions.

MATERIALS AND METHODS

Seven hundred nine cases of focal bone lesions, including 37 central chondrosarcomas, were analyzed according to demographic, anatomic, and plain radiographic features. Vector analysis of groups of features was performed to determine those that are most sensitive and specific for the appearance of central chondrosarcoma in contrast with other lesions in the data base.

RESULTS

The most specific appearance of long bone central chondrosarcomas was a lesion within the medullary cavity with geographic destruction, containing calcified matrix and a diameter greater than 5.9 cm, or arising within the proximal metaphysis or diaphysis. These features all are present in 9 (39%) of the 23 long bone central chondrosarcomas and in less than 1% of other lesions. In flat bone lesions, calcified matrix and either geographic bone destruction, medullary location, or enlargement of the host bone were 100% specific but of low sensitivity, identifying 7 (50%), 7 (50%), and 6 (41%) of the 14 flat bone chondrosarcomas, respectively. Inclusion of calcified matrix in the description is essential to make the criteria specific but excludes several of the most aggressive long bone chondrosarcomas. The vector analysis-generated differential diagnosis include osteosarcoma, fibrous dysplasia, unicameral bone cysts, aneurysmal bone cysts, malignant fibrous histiocytoma, and Ewing sarcoma.

CONCLUSIONS

A relatively specific set of radiographic features can be defined to assist in plain film diagnosis of central chondrosarcoma, but there are many chondrosarcomas that fall outside these parameters. Thus, while not sufficiently sensitive to allow accurate plain film diagnosis in all cases, these criteria serve as an improved foundation for differential diagnosis.

Evaluation of the injured cervical spine: comparison of conventional and storage phosphor radiography with a hybrid cassette

PURPOSE

To compare conventional and storage phosphor radiography of the injured cervical spine.

MATERIALS AND METHODS

Sixty-five patients underwent imaging in a supine position while wearing a cervical collar. Matched storage phosphor and conventional lateral cervical spine radiographs were obtained with an 18 x 24-cm hybrid cassette. Edge-enhanced and nonenhanced copies of each computed radiograph were printed on film, and the images were sent via a computer network to a remote imaging workstation. Four radiologists read the conventional radiographs, the two hard-copy computed radiographs, and the soft-copy images and used a binary scale to score the visibility of bone and soft-tissue structures.

RESULTS

All readers scored better in all areas with computed radiographs, and a statistically significant (P = .030) improvement in performance was seen for soft-tissue structures.

CONCLUSION

Storage phosphor imaging offers advantages over conventional radiography, and digital images may be a viable alternative to film.

Transsphenoid basilar skull fracture: CT patterns

The authors studied computed tomographic (CT) scans obtained in 40 patients with transsphenoid basilar skull fractures to establish if there were reproducible patterns of fracture along lines of weakness. Medical records were reviewed. Four major fracture patterns were identified: anterior transverse (n = 22), lateral frontal diagonal (n = 7), posterior transverse (n = 16), and mastoid diagonal (n = 3). Eight patients had two fracture patterns. Eleven of 40 patients (28%) died as a result of their head injury. The diagonal patterns were statistically significantly more frequently associated with in-hospital mortality than were the transverse fractures (P = .014). Complications included blindness, cranial nerve injury, cerebrospinal fluid leak, and hearing loss. These results indicate that transsphenoid basilar skull fractures occur along reproducible lines of weakness, including a coronal plane through the anterior sphenoid body and pterygoid plates, a coronal plane through the posterior sphenoid body and clivus, and the sphenopetrosal synchondrosis.

Single-exposure conventional and computed radiography. The hybrid cassette revisited

RATIONALE AND OBJECTIVES

The authors constructed and evaluated a hybrid cassette for single-exposure extremity imaging with storage-phosphor plates and conventional radiographic film.

METHODS

A hybrid cassette was constructed using a fine radiographic screen and a storage-phosphor plate. Exposures of a Lucite step wedge and a line pair gauge were made with the hybrid cassette, a conventional radiographic cassette, and a storage-phosphor cassette. The spatial resolution and imaging speeds of the hybrid and standard systems were compared.

RESULTS

Spatial resolution loss was less than 0.5 line pairs per mm with the hybrid cassette. Speed loss was characteristic of the hybrid cassette, requiring approximately 40% greater exposure to produce the same film density as standard cassettes.

CONCLUSIONS

The speed difference between this and a previous study is probably due to differences in film-screen choice, kilovolt peak, and storage-phosphor plate generations. The sensitivity spectrum of our film and the emission spectrum of our screens were more closely matched than were the spectra in the previous study; we used lower kilovolt peak, and our storage-phosphor plates were a later, more efficient, generation. Despite slight speed losses, the hybrid cassette appears to be a better choice for obtaining matched images for clinical trials than the alternative of two separate exposures.