O. Clark West

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.

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.

The HIPAA privacy rule and protected health information: implications in research involving DICOM image databases.

der Much of the medical imaging community now uses th Digital Imaging and Communication in Medicine (DICOM) format, developed by the American College Radiology and the National Electrical Manufacturers A sociation as a standard system for viewing, archiving, retrieving, and transferring images ( 1). Benefits stem from the fact that a single standard provides physicians pra ing within a variety of fields, for different institutions and working with various technologies the ability to readily share images ( 2,3). As the DICOM image forma was integrated into clinical practice, it was subsequent integrated into clinical research and teaching databases The DICOM format is a multipart document that c tains two layers: the header, typically hidden from vie and the viewable image. Most problematic from the standpoint of patient confidentiality is the identifying i formation saved in the DICOM header ( 4). Such information may include patient name, date and time of the exam, participating physicians (ordering, reading), and on. Image dimensions, pixel spacing, slice thickness, s time, and other scanning protocols are also saved in t header. Each variable is stored under a standardized d group and element number. An example would be 0010,0030, where the group number, in this case 0010 the assigned location for much of the patient’s person information, and the element number, 0030, contains t patient’s date of birth. Other examples are the group-e

Early surgical intervention for blunt bowel injury: The Bowel Injury Prediction Score (BIPS)

BACKGROUND Computed tomography (CT) scan of the abdomen has been used for 30 years to evaluate the stable blunt trauma patient. However, the early diagnosis of blunt hollow viscus injury (BHVI) remains a challenge. Delayed diagnosis and intervention of BHVI lead to significant morbidity and mortality. This study aimed to identify a combination of radiographic and clinical variables present at admission that could lead to earlier surgical intervention for BHVI. METHODS Significant predictors were identified through a retrospective review of all blunt trauma patients admitted to a Level 1 trauma center from 2005 to 2010 with an admission CT of the abdomen/pelvis and diagnosed with any mesenteric injury. The Bowel Injury Prediction Score (BIPS) was calculated based on the following three elements with a point given for each outcome: white blood cell count of 17.0 or greater, abdominal tenderness, and CT scan grade for mesenteric injury of 4 or higher. RESULTS A total of 18,927 blunt trauma patients were admitted during the study period. Of these, 380 had a mesenteric injury, 110 met inclusion criteria, 60 had a surgical intervention, and 43 had BHVI. Of the 110 study patients, 43 (39%) had an immediate operation, 17 (16%) had a delayed operation (>4 hours), and 50 (46%) had no surgical intervention. The median BIPS for the immediate and delayed group was 2, while for the no-surgery group, the score was 0. Patients with a BIPS of 2 or greater were 19 times more likely to have a BHVI than patients with a BIPS of less than 2 (odds ratio, 19.2; 95% confidence interval, 6.78–54.36; p < 0.001). CONCLUSION Three predictors (admission CT scan grade of mesenteric injury, white blood cell count, and abdominal tenderness) were used to create a new bowel injury score, with a score of 2 or greater being strongly associated with BHVI. Prospective validation of these retrospective findings is warranted to fully assess the accuracy of the BIPS. LEVEL OF EVIDENCE Prognostic study, level III.

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.

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 × 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, 8am to 5pm). Data were collected before workstation installation (August 1997 to November 1997) and for the subsequent 6 months. Histograms of the number of studies (743v 103) versus report time (mean, 11.7v 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 (11.7v 7.4 hours) and standard deviation (19.8v 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.

Cervical spine trauma radiography: Sources of false-negative diagnoses

We undertook this study to identify causes of false-negative cervical spine plain radiographic interpretations in a series of experimental readings. One hundred eighty-nine examinations (three views), including 97 patients with acute injuries and 92 normal controls from the same emergency room population, were presented to 14 radiologists. The false-negative rate was 17% (2646 readings). The most frequently missed injuries were laminar fractures, atlantoaxial subluxations, pillar fractures, and fractures of C1 and C2. Analysis of 38 cases with 47 fractures missed by two or more readers showed that 20 *43%) involved the C1–C2 area, and 14 (30%) involved the laminae, and articular pillars. Analysis revealed one or more possible contributing causes for the diagnostic error in 21 injuries: marked osteopenia (2), overlying structures (4), a combination of overexposure and overlying structures (2), and satisfaction of search (13). For 26 injuries (55%), no extrinsic cause was evident, and 23 of these (88%) involved the C1–C2 region or the laminar/articular pillar region.

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.

Isolated vertical fracture through the anterior atlas arch: A previously unreported fracture

Vertical linear lucencies through the atlas may be due to congenital clefts or fractures. We report a case of an isolated midline vertical fracture through the anterior atlas arch. The absence of corticated fracture margins on computed tomography distinguished this fracture from a congenital cleft. In similar cases, computed tomography is recommended to identify fractures that might other-wise be dismissed as congenital clefts.

The “night stalker” effect: Are quality improvements with a dedicated night call rotation sustained?

The authors assessed whether the addition of a second-year diagnostic radiology resident assigned to cover the night shift at a major urban university hospital has a sustained effect on the number and clinical significance of “missed” radiologic findings. Radiographs interpreted overnight in the emergency department by radiology residents between January 1992 and December 1992 were reviewed daily by emergency radiology attending staff. A list of patients for whom there was a modification in the final radiologic interpretation was given to the emergency department physicians, who reviewed each case, scored the urgency of patient recall, and estimated the likelihood of patient morbidity attributable to the miss. The relative performance of after-hours residents was compared on the five nights per week with the dedicated night resident vs. the two nights per week without the dedicated night resident (control group).Of 22,295 after-hours examinations performed during the study period, 304 (1.36%) misses were recorded, nearly identical to the miss rate for the preceding 6 months. The percentage per examination interpreted (and number) of missed cases stratified by recall score for the control and dedicated night resident groups, respectively, were: (a) immediate, 0.62% (34) and 0.29% (49); (b) within 48 hours, 0.31% (17) and 0.32% (54); (c) no recall, 0.71% (24) and 0.29% (39); (d) finding already recognized by emergency department physicians, 0.44% (24) and 0.23% (39); total, 2.09% (114) and 1.13% (190). The difference in total discordance rates is statistically significant (P < 1 × 10−15). Our previously reported improvement in the quality of after-hours radiographic interpretation due to the addition of a dedicated night shift resident is sustained in a new group of residents. This confirms that the improvement is real and not a manifestation of the measurement methods.