Should an MR scan be performed routinely after a normal clearance CT scan in the trauma patient? Experience with 59 cases

Magnetic resonance (MR) imaging is not routinely used to exclude ligamentous and other soft tissue injury in the unconscious trauma patient. In order to determine the frequency and types of soft tissue injuries detected by MR imaging but not by computed tomography (CT), we performed a retrospective investigation comparing the MR findings in 59 trauma patients, either alert or unconscious, who previously had undergone a negative clearance multislice CT study of the cervical spine. Six patients had abnormalities not identified on the CT studies, including four cases of ligamentous injury.     

Mediastinal myelolipoma: CT and MRI appearances

A 72-year-old man presented with a mediastinal mass on chest radiograph. Computed tomography and MR imaging showed that the mass consisted of both fatty and small nodular soft tissue components, highly suggestive of an extramedullary hematopoiesis or a myelolipoma. A CT-guided needle biopsy was next performed and confirmed the diagnosis. We discuss the CT and MR imaging appearances of this tumor and usefulness of a CT-guided needle biopsy to avoid surgery in asymptomatic patients. Received: 8 March 1999; Revised: 23 June 1999; Accepted: 25 June 1999     

Acute tamponade after blunt chest trauma

We report a case of high-impact blunt chest trauma resulting in bilateral lung contusion and rupture of the right atrial appendage with subsequent hemopericardium leading to acute right heart failure. Although tamponade remains a clinical diagnosis, in this case CT findings confirmed the diagnosis, initially unsuspected, which led to successful therapeutic intervention. We believe that in patients with high-velocity trauma and possible blunt injury to the chest, a cardiac injury should always be searched for and excluded.     

Local recurrence of rectal cancer: MR imaging before and after oral superparamagnetic particles vs contrast-enhanced computed tomography

The aim of this study was to compare three imaging strategies for the diagnosis of local recurrence of rectal cancer: (a) MR imaging; (b) MR imaging after administration of enteral superparamagnetic particles (Ferristene); and (c) contrast-enhanced CT. Seventeen patients with previous surgery for rectal cancer were examined, 12 patients with local tumour recurrence in the pelvis and 5 patients with postoperative changes. Pelvic multi-coil MR imaging before and after oral administration of superparamagnetic contrast medium [Abdoscan (Ferristene USAN), Nycomed-Amersham, Liding?, Sweden] as well as abdominal and pelvic CT was performed in all patients. The examinations were independently evaluated by three different radiologists. The general effect of the oral MR contrast medium, the delineation of normal and pathological structures as well as confidence in the diagnosis were registered on a visual analog scale (VAS). The diagnosis according to MR before and after oral contrast medium, and CT, was compared, in 16 patients, with the final diagnosis which was verified by biopsy (n = 3), surgery (n = 6), clinical follow-up (n = 4) and by follow-up with MR or CT (n = 3). No significant improvement in MR image quality was found after enteral contrast medium. The post-contrast MR diagnosis was not changed in any of the patients. The diagnosis on MR correlated with the final diagnosis in 12 of 16 patients (sensitivity 91%, accuracy 62%) and the diagnosis on CT in 11 of 16 patients (sensitivity 82 %, accuracy 56 %). The radiologists' "confidence" in the diagnosis and the degree of accordance with the final diagnosis did not score higher on MR after than before oral contrast administration; however, the accordance with the final diagnosis scored better on MR than on CT. No advantages of orally administered superparamagnetic contrast medium were observed in the examined patient group. Magnetic resonance is preferable to CT in diagnosing local tumour recurrence.     

Penetrating trauma to the abdominal aorta: CT demonstration of active bleeding

Contrast-enhanced helical computed tomography (CT) is the imaging study of choice for evaluating the abdomen in hemodynamically stable patients following blunt trauma. Surviving victims of penetrating trauma, in contrast, are often hemodynamically unstable and may require urgent celiotomy with or without diagnostic peritoneal lavage (DPL) or ultrasonography. Abdominal CT is not routinely performed in this patient population, but may be done if the patient with penetrating abdominal trauma is stable on admission or becomes so with resuscitation. CT in this context can address questions regarding the location and extent of injury and help decide appropriate management. We present a case of a stabilized blunt and penetrating trauma patient with negative DPL and active retroperitoneal aortic extravasation demonstrated by CT. To our knowledge, penetrating injury to the aorta with active bleeding has not been previously seen on CT.     

Gleno-humeral instabilities

The purpose of this review is to highlight the most efficient imaging exploratory techniques depicting shoulder instability, to describe its various forms and to point out the findings which can simulate instability. In anterior recurrent dislocation, surgery is indicated and the procedure essentially depends on the importance of glenoid rim lesions. In this case, a standard X-ray evaluation is usually sufficient. The CT arthrography or MRI techniques give more specific details as to the severity of the lesions, particularly soft tissues alterations; however, these data do not alter standard therapeutic protocol. In fixed posterior dislocations, CT scan represents the most pertinent technique to evaluate the size of the humeral head defect and to determine the therapeutic follow-up. In subtle forms of instability, diagnosis or instability direction are not clearly assessed clinically and standard X-ray evaluation is usually unremarkable. In this case, further exploration, such as CT arthrography, MR imaging or MR arthrography, are recommended to confirm the diagnosis of instability and to evaluate its direction. The technique of choice is undoubtedly MR arthrography. Atraumatic voluntary painless subluxations associated with hyperlaxity of the shoulder do not require any specific exploratory method because the findings are generally limited to a capacious axillary pouch. Received: 28 September 1998; Revised: 21 January 1999; Accepted: 22 March 1999     

Thoracic computed tomography in victims of blunt trauma: changes in utilization after the introduction of helical technology

Purpose: In blunt trauma, CT of the thorax is often performed because of the limitations of plain film chest radiography in accurately depicting injuries to the thoracic aorta. The advent of helical CT has allowed the entire chest to be imaged more expeditiously. We will evaluate the extent to which this ability to rapidly obtain additional images of the thorax has increased the utilization of chest CT in blunt trauma. Methods: The radiologic records of all victims of blunt trauma who underwent total body CT (TBCT), which included abdomen, pelvis, and chest images, in the 10 months before and 10 months after our institution acquired helical CT (HCT), were retrospectively evaluated. Results: In the 10 months before we obtained HCT, 520 conventional CT of the abdomen and pelvis were completed, of which only 11 (2.1 %) included images of the full thorax. After HCT was instituted, 684 abdomen and pelvis CT were performed, of which 59 (8.6 %) were ordered with the entire chest. Of the 11 conventional TBCT, 6 (55 %) showed findings in the chest; in 2 of these cases (18 %) the abnormalities were confined exclusively to the thorax. Similarly, of the 59 helical TBCT, 31 (53 %) depicted traumatic abnormalities in the thorax, and in 23 of these cases (39 %) injuries were only within the chest. In 4 of the latter the injuries were mediastinal hematomas, 1 of which (25 %) was confirmed angiographically to represent an aortic laceration. Conclusion: The speed and ease with which additional images can be obtained by HCT has greatly increased utilization of cross-sectional imaging of the thorax after blunt trauma (approximately four-fold). Over half of these depict traumatic injuries.     

Can chest and abdominal trauma CT eliminate the need for plain films of the spine? – Experience with 329 multiple trauma patients

Purpose: To compare the accuracy of spine plain films with chest and abdominal trauma CT in detection of spine fractures. Methods: The study prospectively enrolled 329 multiple trauma patients. Of these, 38 patients had both chest CT for trauma and thoracic spine plain films, and 87 patients had both abdominal CT for trauma and lumbar spine plain films. Results: Of the fractures visible at either chest trauma CT or thoracic spine plain film examination, all were diagnosed on CT and 62 % on plain films. Of fractures visible at either abdominal trauma CT or lumbar spine plain films, 94 % were diagnosed on CT and 67 % on plain films. The one false negative CT involved an articular process fracture, which was visible but not mentioned, in a patient with a sacral fracture. Conclusion: Evaluation of the digital scout images and bone windows when a patient has chest and abdominal trauma CT appears to be as accurate as thoracic and lumbar spine plain films in the evaluation of spinal trauma.     

Radiological follow-up of inverted papilloma

The aim of this study was to describe cross-sectional imaging features of recurrent papilloma of the nasal fossa and paranasal sinuses and to evaluate the role of MR and CT in the postoperative follow-up of this lesion. Magnetic resonance imaging and CT of ten patients who presented recurrence of inverted papilloma were reviewed and correlated to initial imaging, endoscopy, and surgical reports. Imaging patterns of recurrent inverted papilloma are identical to those of initial tumors and recurrence location is closely related to the site of the former lesion. Magnetic resonance is more efficient than CT for the diagnosis and evaluation of extensions. Magnetic resonance supplies the deficiencies of endoscopy in case of extensions to the frontal sinus or the lateral recess of the antrum, especially if mucosal hyperplasia or sinusitis is associated. Magnetic resonance imaging is the first imaging modality to perform in the follow-up after removal of inverted papilloma. Received: 28 April 1999; Revised: 18 November 1999; Accepted: 19 November 1999     

Imaging of blunt chest trauma

In western European countries most blunt chest traumas are associated with motor vehicle and sport-related accidents. In Switzerland, 39 of 10,000 inhabitants were involved and severely injured in road accidents in 1998. Fifty two percent of them suffered from blunt chest trauma. According to the Swiss Federal Office of Statistics, traumas represented in men the fourth major cause of death (4 %) after cardiovascular disease (38 %), cancer (28 %), and respiratory disease (7 %) in 1998. The outcome of chest trauma patients is determined mainly by the severity of the lesions, the prompt appropriate treatment delivered on the scene of the accident, the time needed to transport the patient to a trauma center, and the immediate recognition of the lesions by a trained emergency team. Other determining factors include age as well as coexisting cardiac, pulmonary, and renal diseases. Our purpose was to review the wide spectrum of pathologies related to blunt chest trauma involving the chest wall, pleura, lungs, trachea and bronchi, aorta, aortic arch vessels, and diaphragm. A particular focus on the diagnostic impact of CT is demonstrated. Received: 29 November 1999; Accepted: 28 January 2000     

Magnetic resonance imaging of soft tissue tumors

This article outlines the ability of MR imaging in staging, grading, tissue characterization, and posttherapeutic surveillance of soft tissue tumors. Well-known staging parameters, such as extent, relationship with adjacent structures, and detection of intralesional necrosis, are used in the MR protocol for locoregional staging. Bone scintigraphy and high-resolution CT scan of the lungs are best methods for ruling out metastatic spread. A variety of (solitary or combinations of) grading parameters are described in the radiological literature. The role of MR imaging is to afford recognition of these lesions that need further aggressive work-up, excluding all others. Despite controversial reports, the definite role of MR imaging in grading of soft tissue tumors seems to become established. As for grading, a lot of individual imaging characteristics used for tissue characterization have low sensitivity, but combinations of parameters (age, site, signal intensities) are more useful and often allow to predict a specific diagnosis or to narrow down the list of differential diagnoses. Local recurrences of soft tissue tumors are frequent and can be detected accurately by an easy-to-use MR algorithm.     

Cervical spine injury: accuracy of helical CT used as a screening technique

Objective: The study objective was to determine the sensitivity and specificity of a helical CT technique to screen for cervical spine injury in a high-risk trauma population. Materials and methods: The helical CT reports for a consecutive series of 601 high-risk adult blunt trauma victims were reviewed. Findings were confirmed using an independent reference standard, which consisted of additional cervical spine imaging (CT, MRI, or radiography), operative findings, autopsy results or clinical outcome. Results: Sensitivity and specificity of helical CT for injury were 77/81 (95 %; 95 % confidence limits: 90–100 %) and 484/520 (93 %; 95 % confidence limits 91–95 %) respectively. Four false negative cases were comprised of three missed ligamentous injuries and one missed fracture. False positive cases (n = 36) were mostly attributed to possible facet fracture (n = 6), possible ligamentous injury (n = 8) or technically inadequate scan (n = 6).The overall accuracy of the helical CT protocol for cervical spine injury in this population was 561/601 (93 %; 95 % confidence limits 91–95 %). Conclusion: Helical CT has high accuracy for cervical spine injury. We believe that helical CT should be the preferred imaging strategy in high-risk blunt trauma patients.     

Imaging hemidiaphragmatic injury

The supine chest radiograph is the initial and most commonly performed imaging study to evaluate the thorax after trauma. Whenever the chest radiograph is equivocal or suspicious for acute diaphragmatic injury (DI), computed tomography (CT) is usually the next study of choice since it is both generally available and often used to examine other body regions in the patient after trauma. CT is usually diagnostic, particularly if supplemented by multiplanar reformation (MPR) obtained using thin-slice axial scanning and overlapping images for reformations. Magnetic resonance imaging (MRI) is potentially useful to assess the diaphragm if CT findings are indeterminate and the patient is stable enough to have the procedure. Simple T1-weighted spin-echo images in the sagittal and coronal orientation are usually sufficient to establish or exclude DI. This article reviews imaging modalities and strategies for diagnosing DI from blunt trauma.     

Anterior subluxation of the cervical spine

Anterior subluxation (AS), or hyperflexion sprain, generates a disproportionate level of concern in emergency medicine. Anxiety related to this injury arises from the fact that AS may produce delayed mechanical instability of the cervical spine, with resultant pain and neurological impairment. Furthermore, its radiographic presentation may be very subtle, and it may be impossible to reliably diagnose or exclude this injury using standard screening radiographs. Additional studies, such as flexion–extension (FE) radiography and magnetic resonance (MR) imaging, are often used in the acute setting to assess injury status and radiographically exclude AS injury. There are a number of reasons to discourage this latter practice, which can represent an impossible attempt to “radiographically clear the cervical spine” of blunt trauma patients with “100 % certainty.” This is because AS is an uncommon lesion, and the neurological deficits secondary to delayed instability are almost always minor and transient. Furthermore, AS is usually not entirely occult on screening plain films (which are typically “abnormal” even if in nonspecific ways). Finally, FE imaging, done acutely in the presence of spasm, is probably unable to exclude this diagnosis reliably, even when plain films are normal, and emergent MR, probably the most accurate technique, is not widely available. Risk stratification provides a rational alternative approach for assessing injury status. Low-risk patients may be spared further imaging provided they are given appropriate precautionary return instructions. High-risk patients require emergent evaluation by an experienced spine specialist, and may benefit from advanced imaging. Patients at moderate risk may be best managed with symptomatic treatment, warnings to avoid significant physical activity, and delayed FE imaging and evaluation by a spinal specialist. They should also be instructed to seek immediate medical attention if they develop any indications of delayed instability, including severe pain and /or neurological signs. This stratified approach not only increases the likelihood that delayed subluxation will be recognized before it leads to chronic instability, but frees clinicians and radiologists from the quixotic burden of trying to “clear” the cervical spine with 100 % certainty in the acute setting.     

Standardized whole-body computed tomography as a screening tool in blunt multitrauma patients

The authors present the potential of using a preset CT protocol covering the whole body of the patient who has suffered blunt trauma to screen for injuries, based on a review of the literature and on 4 years' direct experience. Standardized whole-body CT is the fastest method of examining the whole body, capable of detecting a wide variety of traumatic lesions with a high sensitivity and specificity. Multidetector CT allows a full-body examination to be completed within 5 min, thus minimizing time to diagnosis and the institution of definitive clinical care. Current imaging algorithms that include abdominal ultrasonography and plain radiographic studies need to be reassessed in view of the technical advances in CT diagnosis, but should ultimately depend on the particular imaging capabilities and experience of a given trauma center.     

Three-dimensional contrast-enhanced MRI using an intravascular contrast agent for detection of traumatic intra-abdominal hemorrhage and abdominal parenchymal injuries: an experimental study

The aim of this study was to compare the performance of 3D MRI in conjunction with an intravascular contrast agent to spiral contrast-enhanced CT, regarding the detection of abdominal parenchymal injuries as well as peritoneal hemorrhage in an animal model. Liver and kidney injuries were created surgically in six female pigs under general anesthesia. All pigs underwent contrast-enhanced spiral CT and 3D MR imaging following administration of an intravascular contrast agent (NC100150 Injection). Two readers rated their confidence independently on MR and CT data sets using a five-point scale for the presence of organ injury and hemoperitoneum. Autopsy findings served as standard of reference. Sensitivity and specificity for MR in detecting hepatic and renal injuries as well as hemoperitoneum was 100 %. Computed tomography was less accurate with sensitivity and specificity values of 90 and 94 %, respectively. Receiver operating characteristics (ROC) analysis revealed a higher confidence when interpretation was based on MR images. In an animal model 3D MR imaging in conjunction with an intravascular contrast agent proved highly accurate in detecting and localizing parenchymal injuries to the upper abdomen as well as in detecting intraperitoneal blood collections. Received: 4 November 1999, Revised: 5 May 2000, Accepted: 9 May 2000     

Magnetic resonance imaging in the assessment of urologic disease: an all-in-one approach

The aim of this study was to evaluate an “all-in-one” MR procedure to examine the kidneys, the renal vascular supply and renal perfusion, and the urinary tract. In 64 patients (58 with urologic disease and 6 healthy volunteers), MR was performed including: (a) T1- and T2-weighted imaging; (b) 3D contrast-enhanced MR angiography (MRA), including the renal arteries, renal veins, as well as renal perfusion; and (c) 3D contrast-enhanced MR urography (MRU) in the coronal and sagittal plane. For the latter, low- and high-resolution images were compared. Prior to gadolinium injection, 0.1 mg/kg body weight of furosemide was administered intravenously. The results were compared with correlative imaging modalities (ultrasonography, intravenous urography, CT), ureterorenoscopy and/or surgical–pathologic findings. Visualization of the renal parenchyma, the vascular supply, and the collecting system was adequate in all cases, both in nondilated and in dilated systems and irrespective of the renal function. One infiltrating urothelial cancer was missed; there was one false-positive urothelial malignancy. Different MR techniques can be combined to establish an all-in-one imaging modality in the assessment of diseases which affect the kidneys and urinary tracts. Continuous refinement of the applied MR techniques and further improvements in spatial resolution is needed to expand the actual imaging possibilities and to create new tracts and challenges in the MR evaluation of urologic disease. Received: 27 September 1999; Revised: 20 January 2000; Accepted: 22 May 2000     

Insufficiency fractures of the sacrum

Insufficiency fractures of the sacrum are not uncommon. Shared imaging features on radionuclide bone scan, CT, and MR images include linear vertical abnormalities, and unilateral or bilateral distribution. This pattern may be considered sufficiently characteristic to allow a confident correct diagnosis to be made. Radiologists need to have a greater awareness of this condition.     

Value of fluid-attenuated inversion recovery sequences in early MRI of the brain in neonates with a perinatal hypoxic-ischemic encephalopathy

The aim of our study was to assess the usefulness of fluid-attenuated inversion recovery (FLAIR) sequences in comparison with conventional spin-echo and inversion MR imaging in neonates for evaluation of myelination and for detection of hypoxic-ischemic brain injury. We reviewed early MR scans of 18 neonates with suspected hypoxic-ischemic brain damage. Myelination could be evaluated with confidence using conventional MR imaging in all but 2 infants; however, the presence of myelin was very difficult to assess on FLAIR images. Overall, 53 lesions or groups of lesions were identified. The FLAIR technique was more sensitive in 11 of the lesions; especially (pre)cystic lesions could be identified much better and more cysts were found. Conventional MR imaging failed to identify 2 of the lesions and was more sensitive in 14 of the lesions; especially punctate hemorrhages and lesions in basal ganglia or thalami could be better determined. The FLAIR technique missed 3 of these lesions. In the remaining 28 lesions conventional MR and FLAIR images were equally diagnostic. The FLAIR technique and conventional MR imaging are complementary in detecting early sequelae of hypoxic-ischemic brain injury in neonates. The FLAIR technique is not suitable for assessing myelination of the neonatal brain; therefore, FLAIR cannot replace conventional MR imaging. Received: 11 January 2000; Revised: 10 April 2000; Accepted: 10 April 2000     

CT diagnosis of cardiac and pericardial injuries

The purpose of this retrospective study was to determine the CT findings diagnostic of cardiac and pericardial injury, including signs of pericardial tamponade, in patients suffering from blunt and penetrating trauma. A search of the CT radiology database at a level I trauma center was performed to identify cases in which injury to the heart or pericardium was diagnosed, as well as to identify cases of pericardial tamponade. All cases were reviewed to ascertain the specific CT findings, and medical records were reviewed to assess the influence of CT findings on management and to assess for clinical evidence of pericardial tamponade. Eighteen patients had direct CT evidence of cardiac or pericardial injury, including nine cases of pneumopericardium, eight cases of hemopericardium, and one case of intrapericardial gastric herniation. Four of these patients were found to have direct cardiac injuries. Three additional cases with CT evidence of pericardial tamponade were identified, two secondary to cardiac compression by an anterior mediastinal hematoma and one following repair of left ventricular rupture. Of 11 patients with CT evidence of tamponade, only three were suspected clinically. Cardiac and pericardial injuries are usually diagnosed surgically and are often clinically unsuspected, particularly in blunt trauma. As CT is increasingly utilized as a general screening test for thoracic/abdominal trauma, these injuries may be first suspected on the basis of CT findings, and knowledge of the CT findings of cardiac injury or tamponade is crucial.