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Ken F Linnau

Publications and source records attributed to Ken F Linnau.

17 recordsLinked to original sources
PubMed2006

Utility of repeat head computed tomography after blunt head trauma: a systematic review.

BACKGROUND: Repeat head computed tomography (CT) is standard practice for head-injured patients at many trauma centers. Utilization of CT has increased over time, yet effects on outcome and associated risks are unknown. We systematically reviewed the literature to determine the incidence of progression of injury on repeat CT and resulting treatment changes. METHODS: Studies were included from Medline, Embase, and a hand search of citations in reviewed articles. Main outcome measures were progression of injury on repeat CT and resulting intervention. Data were abstracted from 30 eligible studies and discrepancies were settled by consensus. RESULTS: Progression of injury on repeat CT was evident in 8 to 67% of patients in the included studies. Neurosurgical intervention resulting subsequent to a repeat CT occurred in 0 to 54% of patients. More severe traumatic brain injury, defined by Glasgow Coma Scale, was associated with a higher proportion of patients with progression of injury on CT and subsequent neurosurgical interventions. Risk factors associated with progression of injury on CT or resulting intervention were inconsistently reported, but coagulopathy and injury severity were most commonly reported. Few studies reported changes in nonsurgical management, in-hospital disposition, or adverse events associated with obtaining repeat CTs. CONCLUSION: Indications for repeat head CT after traumatic brain injury are unclear. The wide range of reported injury progression on CT and resulting surgical and medical treatment changes suggest there may be a subset of patients who benefit from repeat CT. Further research should stratify by severity of traumatic brain injury, clearly define inclusion and exclusion criteria, address selection bias, quantify progression of injury on CT, determine factors predictive of injury progression and intervention, and assess risks associated with repeat CT.

Disease Progression↗
PubMed2006

Predicting major hemorrhage in patients with pelvic fracture.

BACKGROUND: Pelvic fractures can be an important source of major hemorrhage in victims of blunt trauma. However, no rapid and reliable noninvasive method exists for predicting which subjects will have major hemorrhage. The objective of this study is to use information available upon presentation to the trauma center to develop a clinical prediction rule to identify subjects with pelvic fracture who are at high risk of major hemorrhage. METHODS: A retrospective cohort study was performed on all subjects with pelvic fracture from blunt force mechanism at a single level one trauma center during a 4.3 year period. Chart review identified findings from initial pelvic radiographs and from emergency department care including mechanism of injury, and hemodynamic status. Major hemorrhage was defined by angiographic findings, transfusion requirement and pelvic hemorrhage volume. Logistic regression was used to formulate a clinical prediction rule to stratify subjects based on probability of major hemorrhage. RESULTS: Complete data were available on 627 of 783 eligible subjects. Predictors of major hemorrhage included emergency department hematocrit 30 or less, pulse rate of 130 or greater, displaced obturator ring fracture and pubic symphyseal wide diastasis. Combinations of predictors defined groups with probability of major hemorrhage from 1.6% to 66%. CONCLUSIONS: Probability of major pelvic fracture related hemorrhage can be estimated from initial pelvic radiograph, pulse, and hematocrit.

Adult↗
PubMed2004

Stereotactic 11-gauge vacuum-assisted breast biopsy: influence of number of specimens on diagnostic accuracy.

PURPOSE: To determine whether number of specimens obtained at stereotactic 11-gauge vacuum-assisted breast biopsy with the patient prone influences diagnostic accuracy and to determine whether this number varies depending on mammographic appearance of lesions as masses or microcalcifications. MATERIALS AND METHODS: Biopsy was prospectively performed in 100 patients (median age, 55 years; range, 31-81 years) with 100 lesions that were mammographically evident as masses (n = 50) and microcalcifications (n = 50) with standardized protocol to acquire 20 specimens per lesion in three 360 degrees probe rotations at one skin entry site. Specimens were histologically evaluated sequentially, and findings were compared with results of surgical excision or of mammographic follow-up for at least 24 months. Differences in diagnostic yield after each probe rotation and differences in diagnostic yield between masses and microcalcifications were determined with chi(2) test. RESULTS: Up to 12 specimens harvested within two 360 degrees probe rotations were necessary to yield correct diagnosis in 96% of patients with masses and 92% of patients with microcalcifications. Diagnostic yield was not improved with more than 12 specimens for masses or microcalcifications. In two (4%) of 47 patients with lesions that were eventually diagnosed as cancer, results at stereotactic biopsy indicated they were benign. Underestimation of diagnosis of lesions as atypical ductal hyperplasia and ductal carcinoma in situ occurred in two (50%) of four and two (17%) of 12 lesions, respectively. With 20 specimens harvested during three probe rotations, there was no statistically significant difference in diagnostic yield between patients with masses and those with microcalcifications (P =.68). CONCLUSION: At 11-gauge vacuum-assisted biopsy, highest diagnostic yield was achieved with 12 specimens per lesion, independent of mammographic appearance of the lesion. Even with standardized retrieval of 20 specimens per lesion, underestimation of disease still occurs.

Adult↗
PubMed2003

Assessment of volume of hemorrhage and outcome from pelvic fracture.

HYPOTHESIS: Measurement of pelvic hemorrhage on computed tomographic (CT) scans can estimate the pelvic fracture component of total patient blood loss and predict the need for angiography. DESIGN: Retrospective cohort study. SETTING: Large level 1 trauma center. PATIENTS: We examined data from 759 consecutive, nonreferral blunt trauma patients who sustained pelvic fracture. MAIN OUTCOME MEASURES: Pelvic-fracture-specific outcomes included estimation of extraperitoneal pelvic hemorrhage volume from emergency department CT scans and determination of arterial injury from angiograms. General patient outcomes determined from medical record review included transfusion requirement, estimated blood loss, and mortality. Subanalysis was performed on subjects with only pelvic fracture as a source of major hemorrhage (derived from discharge International Classification of Diseases, Ninth Revision, Clinical Modification codes). RESULTS: Overall mortality was 96 (13%) of 759 patients. Blood transfusion was given to 418 (55%) patients, and 258 (34%) received 6 or more units in the first 72 hours. Pelvic-fracture-related hemorrhage averaged 149 mL (range, 0-1423 mL). Angiography was performed on 163 patients, of whom 113 had arterial injury. Higher pelvic hemorrhage volumes on CT scans were seen in subjects with pelvic arterial injury demonstrated on angiograms (P<.001). In subjects without another source of major hemorrhage, pelvic CT hemorrhage volumes were strongly associated with transfusion requirement (P<.001). Subjects with large pelvic hemorrhage volumes (>500 mL) were more likely to have pelvic arterial injury (risk ratio, 4.8; 95% confidence interval, 3.0-7.8; P<.001) and require large-volume (>/=6 U) transfusions (risk ratio, 4.7; 95% confidence interval, 1.8-12.3; P<.001) than patients with smaller pelvic hemorrhage volumes. CONCLUSION: Pelvic hemorrhage volumes derived from pelvic CT scans were predictors of the need for pelvic arteriography and transfusions.

Adolescent↗
PubMed2003

Evidence-based approach to using CT in spinal trauma.

Computed tomography has revolutionized the diagnosis and treatment planning of the acutely injured spine. In the cervical spine, its appropriate use can improve outcome and save money. Although there are no clinical prediction rules validated outside of the cervical spine, these proven capabilities have been extrapolated to the thoracolumbar spine.

Evidence-Based Medicine↗
PubMed2003

Evidence-based approach to use of MR imaging in acute spinal trauma.

MR imaging directly shows integrity of spinal cord, and provides sensitive assessments of structurally important soft tissue investments of the vertebral column. High-resolution images should be acquired in at least two planes, with T1 and fluid sensitive sequences. In the acute and subacute settings, MR may be used to assess integrity of intervertebral discs prior to closed reduction of inter-facetal dislocations, to discriminate between neurological deficits due to intra-substance hemorrhage or edema, and to determine the status of spinal ligaments as an adjunct to 'clearing' the spine.

Acute Disease↗
PubMed2003

Imaging of chest trauma: radiological patterns of injury and diagnostic algorithms.

In patients after chest trauma, imaging plays a key role for both, the primary diagnostic work-up, and the secondary assessment of potential treatment. Despite its well-known limitations, the anteroposterior chest radiograph remains the starting point of the imaging work-up. Adjunctive imaging with computed tomography, that recently is increasingly often performed on multidetector computed tomography units, adds essential information not readily available on the conventional radiograph. This allows better definition of trauma-associated thoracic injuries not only in acute traumatic aortic injury, but also in pulmonary, tracheobronchial, cardiac, diaphragmal, and thoracic skeletal injuries. This article reviews common radiographic findings in patients after chest trauma, shows typical imaging features resulting from thoracic injury, presents imaging algorithms, and recalls to the reader less common but clinically relevant entities encountered in patients after thoracic trauma.

Algorithms↗
PubMed2003

Orbital apex injury: trauma at the junction between the face and the cranium.

Orbital apex injury is usually seen in multiply and severely injured patients who are subject to high-energy trauma. Orbital apex injury rarely occurs in isolation. By proximity, the face, the skull base, or their combination are the most likely regions to be injured in association with orbital apex trauma. The vast majority of these injuries occur as an extension of orbital, LeFort, naso-orbito-ethmoid, panfacial, sphenoid, or temporal bone fractures of the skull. Complex osseous anatomic structures with intimately related multiple neurovascular organs make injuries to the orbital apex diagnostically and therapeutically challenging. Often other facial fractures extend into the orbital apex, or the orbital apex is damaged in conjunction with fractures of the skull base. Therefore abnormal imaging findings within the orbital apex may be indicators of traumatic injury to the entire junctional zone of face and cranium. In this article, we will give an overview of normal CT anatomy, review clinical syndromes, which may indicate traumatic injury of the orbital apex and present an imaging strategy for evaluation of the orbital apex.

Humans↗
PubMed2003

Imaging of high-energy midfacial trauma: what the surgeon needs to know.

UNLABELLED: Treatment goals in severe midfacial trauma are restoration of function and appearance. Restoration of function is directed at multiple organ systems, which support visual acuity, airway patency, mastication, lacrimation, smelling, tasting, hearing, and facial expression. Victims of blunt facial trauma expect to look the same after surgical treatment as before injury. Delicate soft tissues of the midface often make cosmetic reconstructive surgery technically challenging. Generally, clinical evaluation alone does not suffice to fully characterize facial fractures associated with extensive swelling, and the deeper midface is not accessible to physical examination. Properly performed computed tomography (CT) overcomes most limitations of presurgical examination. Thus, operative approaches and sequencing of surgical repair are guided by imaging information displayed by CT. Restoration of function and appearance relies on recreating normal maxillofacial skeletal anatomy, with particular attention to position of the malar eminences, mandibular condyles, vertical dimension and orbital morphology. Due to its pivotal role in surgical planning, CT scans obtained for the evaluation of severe midfacial trauma should be designed to easily depict the imaging information necessary for clinical decision making. LEARNING OBJECTIVES: 1. Understand the facial skeletal buttress system; 2. Understand how the pattern of derangement of the buttress system determines the need for and choice of operative approach for repair of fractures in the middle third of the face; 3. Understand the role and importance of CT and CT reformations in the detection and classification of the pattern of buttress system derangement.

Humans↗
PubMed2003

Web-based image review and data acquisition for multiinstitutional research.

OBJECTIVE: In this article, we describe a user-friendly Web-based interface that allows review of images combined with integrated data collection and entry for use at multiple sites involved in a large multicenter research project. CONCLUSION: The Web-based system that we present uses a commercially available Internet browser and Web platform and allows automated data entry that can be easily uploaded into standard data analysis programs. The system simplifies the complex logistics of using multiple sites and reviewers for radiology research and can preserve human subject confidentiality. We tested the system using a large-scale multicenter cohort study of pelvic fracture-related hemorrhage (the "Evaluating Pelvic Hemorrhage" study). Program testing revealed seamless remote image interpretation and data acquisition.

Biomedical Research↗
PubMed2002

Can CT predict the source of arterial hemorrhage in patients with pelvic fractures?

The objective of the study was to evaluate the ability of hemorrhage site and location as demonstrated on pelvic CT to predict the source of arterial hemorrhage in patients with traumatic pelvic fractures. CT scans of 104 consecutive patients who had sustained traumatic pelvic fracture and undergone emergent pelvic angiography were digitized, and fracture-related hemorrhage area and volume were measured at multiple locations within the pelvis. Clots that measured greater than 10 cm(2) were compared to angiographic results. The chi(2) test was used to find locations on CT that were significantly associated with specific arterial injuries found on angiography. Sixty-one (58%) of the patients had arterial bleeding at angiography. The most commonly injured arteries were the internal pudendal and the superior gluteal. Specific locations on CT were statistically significant indicators of injury to the superior gluteal artery (relative risk=2.9, 95% CI 1.2-7.3, P=0.013), the anterior division of the internal iliac artery (relative risk=3.2, 95% CI 1.4-4.1, P=0.006), and the internal pudendal arteries (relative risk=2.0, 95% CI 1.1-4.0, P=0.037). More blood was visible on CT when an artery was injured (mean volume with negative angiogram=318 ml, mean volume with positive angiogram=554 ml, ( P=0.007)). The rectus sheath region at the top of the iliac crest ( P=0.004), pelvic sidewalls at the L5-S1 disk space level ( P=0.001), and gluteal regions also at the L5-S1 disk space level ( P=0.012) were significant indicators of a positive arteriogram. CT can help predict the specific bleeding artery to potentially guide angiographic intervention.

Journal Article↗
PubMed2002

Radiologic and clinical spectrum of occipital condyle fractures: retrospective review of 107 consecutive fractures in 95 patients.

OBJECTIVE: We proposed to characterize the radiologic spectrum of occipital condyle fractures in a large series of patients and to correlate fracture pathology with neurosurgical treatment and patient outcome. MATERIALS AND METHODS: We conducted a retrospective review of the findings on conventional radiography, CT, and MR imaging in 95 patients with 107 occipital condyle fractures. We described fracture patterns according to two previously published classification systems. Clinical findings, neurosurgical management, and patient outcome were obtained from the medical records. RESULTS: Inferomedial avulsions (Anderson and Montesano type III) were the most common type of occipital condyle fracture, constituting 80 (75%) of 107 overall fractures. Unilateral occipital condyle fractures were found in 73 (77%) of 95 patients, and 58 patients were treated nonoperatively; occipitocervical fusion was required in nine patients for complex C1-C2 injuries, and six patients died. Bilateral occipital condyle fractures or occipitoatlantoaxial joint injuries were seen in 22 (23%) of 95 patients. Occipitocervical fusion or halo traction for the craniocervical junction was required in 12 patients, all of whom had CT evidence of bilateral occipitoatlantoaxial joint disruption and six of whom showed normal craniocervical relationships on conventional radiographs. Six patients with nondisplaced fractures were treated nonoperatively, and four patients died. Thirty (32%) of 95 patients showed continued disability, whereas 55 (57.5%) of 95 patients had good outcomes at 1 month. Associated cervical spine injuries were present in 29 (31%) of 95 patients. CONCLUSION: Given their associated traumatic brain and cervical spine injuries, occipital condyle fractures are markers of high-energy traumas. That conventional radiographs alone may miss up to half of the patients with acute craniocervical instability has not been well established. Avulsion fracture type and fracture displacement are associated with both injury mechanism and the need for surgical stabilization. In this series, most unilateral occipital condyle fractures were treated nonoperatively, whereas bilateral occipitoatlantoaxial joint injuries with findings of instability usually required surgical stabilization.

Adolescent↗
PubMed2002

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.

Adult↗
PubMedDate not supplied

Bony injuries of the shoulder.

The complex anatomy and functioning of the shoulder may challenge the radiologist. In this review the patterns of injury and radiographic findings for bony injuries of the shoulder are illustrated. The radiographic and cross-sectional imaging findings in fractures of the clavicle, scapula, and proximal humerus and in dislocations of the sternoclavicular, acromioclavicular, and glenohumeral articulations are discussed.

Humans↗