Depiction of pelvic fractures using 3D volumetric holography: comparison of plain X-ray and CT

Optimizing analysis, visualization, and navigation of large image data sets: one 5000-section CT scan can ruin your whole day

The technology revolution in image acquisition, instrumentation, and methods has resulted in vast data sets that far outstrip the human observers' ability to view, digest, and interpret modern medical images by using traditional methods. This may require a paradigm shift in the radiologic interpretation process. As human observers, radiologists must search for, detect, and interpret targets. Potential interventions should be based on an understanding of human perceptual and attentional abilities and limitations. New technologies and tools already in use in other fields can be adapted to the health care environment to improve medical image analysis, visualization, and navigation through large data sets. This historical psychophysical and technical review touches on a broad range of disciplines but focuses mainly on the analysis, visualization, and navigation of image data performed during the interpretive process. Advanced postprocessing, including three-dimensional image display, multimodality image fusion, quantitative measures, and incorporation of innovative human-machine interfaces, will likely be the future. Successful new paradigms will integrate image and nonimage data, incorporate workflow considerations, and be informed by evidence-based practices. This overview is meant to heighten the awareness of the complexities and limitations of how radiologists interact with images, particularly the large image sets generated today. Also addressed is how human-machine interface and informatics technologies could combine to transform the interpretation process in the future to achieve safer and better quality care for patients and a more efficient and effective work environment for radiologists.

SUPPLEMENTAL MATERIAL

http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.11091276/-/DC1.

Haemodynamically unstable pelvic fractures

Bleeding pelvic fractures that result in haemodynamic instability have a reported mortality rate as high as 40%. Because of the extreme force needed to disrupt the pelvic ring, associated injuries are common and mortality is usually from uncontrolled haemorrhage from extra-pelvic sources. Identifying and controlling all sources of bleeding is a complex challenge and is best managed by a multi-disciplinary team, which include trauma surgeons, orthopaedic surgeons and interventional radiologists. Once the pelvis is identified as the major source of haemorrhage, component therapy reconstituting whole blood should be used and the pelvic region wrapped circumferentially with a sheet or pelvic binder. Patients at risk for arterial bleeding who continue to show haemodynamic instability despite resuscitative efforts should undergo immediate arteriography and embolisation of bleeding pelvic vessels. If this is unavailable or delayed, or the patient has other injuries (i.e., head, chest, intra-abdominal, long bone), external fixation and pelvic packing, performed concomitantly with other life-saving procedures, may be used to further reduce pelvic venous bleeding. If however, the patient remains haemodynamically labile without apparent source of blood loss, transcatheter angiographic embolisation should be attempted to locate and stop pelvic arterial bleeding. Institutional practice guidelines have been shown to reduce mortality and should be developed by all centres treating pelvic fractures.

Hemodynamically Unstable Pelvic Fractures: Recent Care and New Guidelines

Consistent care of hemodynamically unstable pelvic fracture patients is a major management issue. It was uncertain whether the introduction of newly developed clinical practice guidelines would require much change in current delivery of care at our institution. Assessment of recent care was undertaken and compared with the newly developed evidence-based best practice guidelines. A multidisciplinary project team developed clinical practice guidelines for determination of early optimum management of hemodynamically unstable patients with pelvic fractures. The guidelines recommend a definitive management plan to arrest hemorrhage within 30 minutes. Intra-abdominal hemorrhage should be assessed with diagnostic peritoneal aspiration (DPA) and/or focused assessment with sonography for trauma (FAST). Early noninvasive stabilization of the pelvis followed by angiography within 90 minutes are recommended if intra-abdominal hemorrhage is not found. Recent care was assessed in a historical cohort of patients, identified in a prospectively maintained trauma registry, between June 1999 and December 2001. Investigations, interventions, and times were then compared with the new guidelines. The delivery of care to 30 patients (mortality 37%, mean ISS 37.8 +/- 20.9) was studied. Compared with the new guidelines, the abdominal assessment rate with DPA and/or FAST was 53% and early (< 90 minutes) angiography rate was 38%. A form of pelvic external stabilization was applied in 27% of cases. Noninvasive pelvic stabilization was not performed at all. The recent care of hemodynamically unstable pelvic fracture patients was not in line with newly developed guidelines. There is an opportunity to markedly improve the rates of initial assessment of the abdomen, pelvic stabilization, and early angiography.

Traumatic injuries of the pelvis and thoracic and lumbar spine: does thin-slice multidetector-row CT increase diagnostic accuracy?

The objective is to evaluate different multidetector-row CT (MDCT) strategies for adequate classification of spinal and pelvic injuries. Seventy intubated patients after multiple trauma underwent conventional radiography (CR) and MDCT. Examinations included the pelvis (P), the lumbar spine (LS) and the thoracic spine (TS). Conventional radiographs, 3-mm (CT5) and 5-mm scans (CT3) and 3-mm and 5-mm scans combined with MPR (CT3R/CT5R) were compared to surgery, autopsy and clinical course. MDCT led to significantly better results than CR (P<0.01). Correlation coefficients were r=1.0 (CT3R), r=0.96 [TS] to r=1.0 [P/LS] (CT5R), r=0.8 [P] to r=1.0 [TS] (CT3), r=0.80 [P] to r=0.86 [TS] (CT5) and r=0.3 [TS] to r=0.69 [P] (CR). Fractures were identified by CT3R in 100% of cases, by CT5R in 95%, by CT3 in 90% [P]-100% [TS], by CT5 in 83.3% [LS]-90% [P] and by CR in 57.1% [TS]-87.2% [P]. Unstable fractures were identified in 100% by CT3R, CT5R and CT3, 85.7% [TS]-100% [P/LS] by CT5 and 57.1% [TS]-80% [P] by CR. Only overlapping thin-slice multiplanar reformation allows for an adequate classification of spinal and pelvic injuries and thus is highly emphasized in patients after severe blunt trauma.

Guidelines for the management of haemodynamically unstable pelvic fracture patients

BACKGROUND

Haemodynamically unstable pelvic fracture patients have a high mortality, and decision-making is crucial. The present article discusses key clinical practice guidelines and options in the early management of these challenging patients.

METHODS

A multidisciplinary consensus committee developed guidelines following standard scientific methodology, comprehensive Medline searches and level of evidence grading. Clinical practice guidelines and options addressed four key questions: (i) how to determine the source of haemorrhage?; (ii) how to control haemorrhage?; (iii) what is the optimal angiography and embolization technique?; and (iv) what is the optimal pelvic stabilization technique?

RESULTS

The consensus best evidence recommends that the source of intra-abdominal haemorrhage should be assessed using diagnostic peritoneal aspiration and/or focused abdominal sonography in trauma within 30 min of patient arrival. Immediate laparotomy and concomitant pelvic stabilization control intra-abdominal haemorrhage and venous pelvic haemorrhage, followed by angiography if pelvic arterial bleeding is also present. If intra-abdominal bleeding is absent, non-invasive pelvic stabilization and transfer to angiography within 45 min of arrival is recommended to control venous and arterial pelvic haemorrhage. Optimal embolization is performed with steel coils or Gelfoam (Pharmacia & Upjohn, Peapack, NJ, USA) suspension. The optimal pelvic stabilization technique for rotationally unstable fractures with haemodynamic instability is non-invasive.

CONCLUSION

The consensus committee successfully developed best evidence recommendations identifying the issues and providing guidelines and options for this challenging condition.

Magnetic resonance diffractive imaging

Magnetic resonance (MR) diffractive imaging is proposed as a new approach to MR angiography. The expression of the nuclear MR signal is similar to the equation for the Fresnel diffraction of a three-dimensional (3-D) object in light or sound waves. The proposed technique offers the possibility of fast angiographic imaging and the on-line reconstruction of 3-D volumetric images using the holographic technique. Static imaging experiments using an ultra-low-field MRI system are performed to verify the feasibility of the technique. It is shown that the images focused on an arbitrary plane can be reconstructed from data scanned in two dimensions, even though blurred image data is superimposed on the image. Moreover, the 3-D image can be observed in a coherent optical imaging system. This study demonstrates the possibility of the proposed method as a fast imaging technique for MR angiography.

Dynamic holographic imaging of the beating human heart

Background--Currently, the reporting and archiving of echocardiographic data suffer from the difficulty of representing heart motion on printable 2-dimensional (2D) media. Methods and Results--We studied the capability of holography to integrate motion into 2D echocardiographic prints. Images of normal human hearts and of a variety of mitral valve function abnormalities (mitral valve prolapse, systolic anterior motion of the mitral leaflets, and obstruction of the mitral valve by a myxoma) were acquired digitally on standard echocardiographic machines. Images were processed into a data format suitable for holographic printing. Angularly multiplexed holograms were then printed on a prototype holographic "laser" printer, with integration of time in vertical parallax, so that heart motion became visible when the hologram was tilted up and down. The resulting holograms displayed the anatomy with the same resolution as the original acquisition and allowed detailed study of valve motion with side-by-side comparison of normal and abnormal findings. Comparison of standard echocardiographic measurements in original echo frames and corresponding hologram views showed an excellent correlation of both methods (P<0.0001, r2=0.979, mean bias=2.76 mm). In this feasibility study, both 2D and 3D holographic images were produced. The equipment needed to view these holograms consists of only a simple point-light source. Conclusions--Holographic representation of myocardial and valve motion from echocardiographic data is feasible and allows the printing on a 2D medium of the complete heart cycle. Combined with the recent development of online holographic printing, this novel technique has the potential to improve reporting, visualization, and archiving of echocardiographic imaging.

Current concepts in imaging of the pelvis and hip

Over the past decade, imaging evaluation of orthopedic conditions of the pelvis and hips has become increasingly complex. Although the conventional radiograph remains the initial examination of choice, the decision between secondary tests, such as computed tomography, MR imaging, or scintigraphy is far from clear. A thorough understanding of current imaging technology is necessary for the clinician to choose the most appropriate examination for a given situation. This article reviews the current status of orthopedic imaging in the areas of acute trauma, stress injuries, osteonecrosis, arthropathies, tumors, and interventional imaging.