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.