Biomedical subjects
Publications and source records attributed to Stuart E Mirvis.
This article emphasizes multirow detector CT (MDCT) technique, the spectrum of findings for diagnosing major thoracic vascular injuries, and the challenges and potential errors that might be encountered. In particular, the role of MDCT data after processing to enhance diagnostic accuracy and convey appropriate and required diagnostic information to the doctors who are managing these vascular injuries are discussed.
OBJECTIVE: Chance-type fractures are subtle unstable injuries that are often associated with intraabdominal injuries. CT-based observations made during routine interpretations revealed involvement of a burst component to this fracture pattern and a clue on the transaxial images to its presence. The purpose of this review was to determine how often these features occurred in a retrospective study of a large sample because these findings influence diagnosis and management. MATERIALS AND METHODS: A retrospective review of all patients identified from the University of Maryland Shock Trauma Center trauma registry and IDXRad system diagnosed with flexion-distraction injuries of the thoracolumbar spine over an 8-year period was performed. Three trauma radiologists assessed the admission spinal radiographs, CT studies with multiplanar images, and available MRI examinations. Imaging findings were confirmed by consensus. Abdominopelvic CT studies and surgical reports were reviewed for evidence and type of intraabdominal injury. A literature review of previous similar series was performed. RESULTS: Fifty-three patients were identified for inclusion in the study. Associated intraabdominal injury occurred in 40% and most commonly involved the bowel and mesentery. A close examination of the fracture patterns on CT revealed that a burst-type fracture with posterior cortex buckling or retropulsion was a common finding (48%). Also, serial transaxial CT images often (76%) showed a gradual loss of definition of the pedicles that we refer to as the "dissolving pedicle" sign. The study showed that the horizontally oriented fracture planes through the posterior elements can often be recognized radiographically, but these fractures can be very subtle. CONCLUSION: Intraabdominal injuries occurred in 40% of flexion-distraction thoracolumbar fractures in our study cohort, which is slightly lower than previously reported. About half of the patients with this injury displayed a burst-type component that could have a significant influence on surgical management. The dissolving pedicle sign can assist in recognition of this often subtle injury on transaxial CT.
Chest radiography remains the primary screening study for the assessment of victims of chest trauma, but computed tomography (CT), particularly multidetector CT (MDCT), has progressively changed the imaging approach to these patients. MDCT acquires thinner sections with greater speed, allowing higher quality axial images and nonaxial reformations than conventional or single-detector helical CT. The speed of MDCT, both in acquiring data and in reconstructing images, makes the performance of total body surveys in the blunt polytrauma patient practicable. In general, CT has been well documented to offer major advantages over chest radiography in both screening for thoracic injuries and in characterizing such injuries. This capacity has been enhanced by the application of multichannel data acquisition. The greater sensitivity of MDCT has been well demonstrated in diagnosing vascular and diaphragmatic injuries. This article reviews current concepts of diagnostic imaging in acute chest trauma from blunt force and penetrating mechanisms emphasizing the spectrum of diagnostic imaging findings for various injuries, based primarily on radiographic and CT appearances. The advantages of MDCT for selected injuries are emphasized.
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PURPOSE: To review the current medical literature on dynamic fluoroscopic and magnetic resonance (MR) imaging assessment of cervical spine stability in obtunded patients who sustained blunt trauma. MATERIALS AND METHODS: The English-language literature within the Swetswise and Medline databases was searched for articles describing dynamic fluoroscopic or MR imaging assessment of cervical spine stability in patients who sustained blunt trauma. Patients with fractures or radiographic signs of injury were excluded. The frequencies of purely ligamentous injuries, injuries requiring immobilization, and other clinically important nonligamentous abnormalities were determined. RESULTS: The frequency of isolated cervical ligamentous injuries diagnosed with dynamic fluoroscopy, as reported in the literature, was 0.9% (11 of 1166 patients), whereas the reported frequency of these injuries diagnosed with MR imaging was 22.7% (125 of 550 patients). All injuries diagnosed with dynamic fluoroscopy and 101 (80.8%) of those diagnosed with MR imaging required continued cervical immobilization. Six (60%) of 10 injuries diagnosed with dynamic fluoroscopy and seven (5.6%) of 125 injuries diagnosed with MR imaging required surgical or halo stabilization. Five (2.5%) of the 200 obtunded patients assessed with MR imaging and six (0.5%) of the 1166 obtunded patients evaluated with dynamic fluoroscopy required surgery. CONCLUSION: Review of the current medical literature provided no clear evidence of the superiority of either MR imaging or dynamic fluoroscopy in the diagnosis of unstable ligamentous injury, although other relative advantages of MR imaging indicate that it is preferred for assessing cervical spine stability in obtunded blunt trauma patients.
PURPOSE: To retrospectively determine what information, if any, magnetic resonance (MR) imaging of the cervical spine in obtunded and/or "unreliable" patients with blunt trauma adds to multi-detector row computed tomography (CT) of the entire cervical spine (including routine multiplanar sagittal and coronal reformations) when the CT findings are normal. MATERIALS AND METHODS: The study was HIPAA compliant and institutional review board approved. Informed consent was not required. From April 2001 to November 2003, 1400 trauma patients underwent MR imaging of the cervical spine to evaluate potential cervical spine injuries. Multi-detector row CT of the cervical spine was performed with a four- or 16-detector row scanner. MR imaging of the cervical spine was performed with transverse gradient-echo, sagittal intermediate-weighted, sagittal short inversion time inversion-recovery, and sagittal T1- and T2-weighted fast spin-echo sequences. Many MR examinations were performed to exclude soft-tissue injuries in the cervical spine of obtunded patients with blunt trauma in whom cervical spine injury could not be excluded with physical examination. Complete cervical spine MR studies were obtained to evaluate soft-tissue injuries in 366 obtunded patients with blunt trauma (281 male and 85 female patients; age range, 13-92 years; mean age, 42.1 years). The patients had previously undergone total cervical spine multi-detector row CT with normal findings. The results obtained with these two modalities were compared. RESULTS: MR images were negative for acute injury in 354 of the 366 patients and negative for cervical spine ligamentous injury in 362. Seven of the 366 patients had cervical cord contusions, four patients had ligamentous injuries, three patients had intervertebral disk edema, and one patient had a cord contusion, a ligamentous injury, and an intervertebral disk injury. Four patients had ligamentous injuries; however, all of these patients had ligament injuries limited to only one of the three columns of cervical spine ligament support. Multi-detector row CT had negative predictive values of 98.9% (362 of 366 patients) for ligament injury and 100% (366 of 366 patients) for unstable cervical spine injury. CONCLUSION: A normal multi-detector row CT scan of the total cervical spine in obtunded and/or "unreliable" patients with blunt trauma enabled the authors to exclude unstable injuries on the basis of findings at follow-up cervical spine MR imaging.
Abdominal ultrasonography (US) is gaining widespread acceptance as a valuable diagnostic tool in the initial evaluation of trauma victims. We investigated the utility of US as a follow-up radiologic study in nonoperative hepatic trauma. Patients with liver injury designated for nonoperative management were prospectively studied over a 2-year period at our primary adult resource center for trauma. Computed tomography (CT) and radiologist-performed US were obtained at admission and at 1 week. The ability of US to detect lesions, fluid, and complications was evaluated by comparing with the corresponding CT. Twenty-five hepatic trauma patients in the study were successfully managed nonoperatively and had both initial and follow-up US and CT scans: 1 (4%) grade I, 5 (20%) grade II, 7 (28%) grade III, 7 (28%) grade IV, and 5 (20%) grade V. Four complications developed [biloma (3) and biliary fistula (1)] in 3 patients with grade IV injury and 1 with a grade II injury. Interval US appropriately detected a complication or confirmed the absence of complication in all (13/13, 100%) patients with low-grade (I-III) injury and only missed a small biloma in one patient with a grade IV injury. Interval US and CT agreement was 92 per cent for change in hemoperitoneum or parenchymal lesion. Ultrasonography is a convenient imaging modality in the evaluation of hepatic trauma. US is sufficient to detect or exclude complications in low-grade injuries. In high-grade injuries, US may be an adjunct to CT for definitive interval assessment.
PURPOSE: To assess the accuracy of computed tomography (CT) in demonstrating the presence or absence of peritoneal violation and type of intraperitoneal organ injury, if any, in hemodynamically stable patients with penetrating torso trauma but without definite peritoneal signs or radiographic evidence of free intraperitoneal air. MATERIALS AND METHODS: During a 29-month period, helical CT with oral, rectal, and intravenous contrast material (triple-contrast) was performed in 200 hemodynamically stable patients, including 169 men (age range, 15-85 years; mean age, 31 years) and 31 women (age range, 17-45 years; mean age, 28 years) with penetrating torso trauma. The study group included 86 patients with gunshot wounds, 111 with stab wounds, and three impaled by sharp objects. CT scans were evaluated prospectively by three trauma radiologists for evidence of peritoneal violation to determine injury to intra- or retroperitoneal solid organs, bowel, mesentery, vascular structures, diaphragm, and urinary tract. Sensitivity, specificity, and accuracy of CT in the diagnosis of peritoneal violation were determined. RESULTS: CT findings aided diagnosis of peritoneal violation in 34% of patients (68 of 200) and were negative for peritoneal violation in 66% of patients (132 of 200). Two patients with negative CT findings failed to improve with observation and underwent therapeutic laparotomy. CT had 97% sensitivity (66 of 68 findings), 98% specificity (130 of 132 findings), and 98% accuracy (196 of 200 findings) for peritoneal violation. CT aided diagnosis of 28 hepatic, 34 bowel or mesenteric, seven splenic, and six renal injuries. Laparotomy based on CT findings in 38 patients was considered therapeutic in 87% (33 of 38) and nontherapeutic in 8% (three of 38) and had negative results in 5% (two of 38). CONCLUSION: Triple-contrast helical CT accurately demonstrates peritoneal violation and visceral injury in patients with penetrating torso wounds.
In recent years, the advent of multidetector CT (MDCT) has begun to change the imaging approach to patients sustaining blunt or penetrating thoracic injury. The ability to directly detect some injuries that are often occult on chest radiography, such as pericardial hemorrhage, major thoracic vascular injury, small pneumothorax, and diaphragm tears, as well as the ability to better define the extent of other injuries, such as lung contusion and laceration, account for this transition. This article reviews current concepts of diagnostic imaging in acute chest trauma from both blunt force and penetrating mechanisms, emphasizing the spectrum of diagnostic imaging findings for various injuries, primarily based on multidetector MDCT.
PURPOSE: The purpose of this study was to determine whether admission non-computed tomography (CT) criteria can exclude intra-abdominal injury in stable patients sustaining blunt abdominal trauma. METHODS: Seven hundred fourteen hemodynamically stable patients with suspicion of blunt abdominal trauma were included in the study. Admission data for clinical examination, sonography, routine laboratory studies, chest/pelvic radiographic findings, and Glasgow Coma Scale (GCS) score were recorded. Each patient underwent helical abdominal CT. Injuries were considered major if they required surgery or angiographic intervention. At the authors' institution, angiography is routinely performed if there is a splenic injury of American Association for the Surgery of Trauma grade II or higher or a liver injury of American Association for the Surgery of Trauma grade III or higher. Statistical analysis was performed to determine the value of isolated and combined clinical, radiologic, and laboratory parameters in depicting an intra-abdominal injury with regard to CT results and clinical follow-up. RESULTS: The best combination of criteria to identify a major abdominal injury was obtained when sonography, chest radiography, and three laboratory parameters (serum glutamic oxaloacetic transaminase, white blood cell count, and hematocrit) were normal: 22% (129 of 589) of patients without major injuries fulfilled these criteria. The only combination of criteria that completely excluded intra-abdominal injury was obtained when clinical criteria combined with a Glasgow Coma Scale score > 13, bedside radiologic studies, and laboratory data were all normal, but only 12% (68 of 578) of patients without abdominal injury fulfilled these criteria. CONCLUSION: After blunt abdominal trauma, admission non-CT criteria can at best identify 12% of patients without intra-abdominal injuries and 22% of patients without major injuries.
BACKGROUND AND PURPOSE: Patients with traumatic brain injury (TBI) and low Glasgow coma scale (GCS) scores may have severe injury associated with cellular disruption that can be studied with whole-brain apparent diffusion coefficient (ADC) histograms. We retrospectively studied this hypothesis and correlated ADC with GCS. METHODS: Twenty-one patients (37.81 +/- 41.3 years) with TBI were enrolled: Group A had normal MR imaging findings but low GCS scores (n = 6). Group B had brain stem injury with low GCS scores (n = 6). Group C had cortical lesions with normal GCS scores (n = 5), and group D had cortical lesions with low GCS scores (n = 4). Eleven control subjects were enrolled (32.7 +/- 19.2 years). Whole-brain ADC maps and histograms were generated and normalized for each subject. Mean and peak ADCs were determined. A one-sided t test was performed for each parameter. Average GCS scores and corresponding peak and mean ADCs were correlated. RESULTS: Peak histogram values significantly differed between controls and groups A, B, and D (P <.0019, P <.00129, and P <.0148, respectively). In groups A and D, values were significantly skewed compared with control values. Mean ADC was significantly different between the control ADC and group A (P <.013) but not group C. In each group, peak ADC and GCS score were strongly correlated (R(2) = 0.67). CONCLUSION: Whole-brain peak ADCs and GCS scores are significantly correlated in patients with TBI. Although conventional MR images were normal, ADC independently indicated TBI and better represents the degree of neurologic dysfunction.
This is a case report of diving related decompression sickness causing spinal cord symptoms and unique MR findings. The clinical and imaging manifestations are examined, while the pathophysiology of decompression sickness is reviewed. The variety of imaging findings from similar reported clinical cases have are also discussed.
Traumatic diaphragmatic injury (TDI) occurs in approximately 6% of patients after major blunt trauma to the abdomen. Detection of such injuries is often problematic because of nonspecific clinical signs and the presence of additional intra-abdominal injuries. As the use of nonsurgical management to treat solid organ injuries increases, helical computed tomography (CT) must play a much greater role in the detection of intra-abdominal injuries. Therefore, it is crucial that diaphragmatic injuries are not overlooked, as fewer will be diagnosed at exploratory laparotomy. This article reviews the recent advances in helical CT that are helpful in diagnosing TDI and addresses the selected application of magnetic resonance imaging.
OBJECTIVE: The purpose of this study was to describe the performance of adjunctive radiologic imaging in patients with cervical spine injury. METHODS: All patients undergoing cervical spine radiography were prospectively enrolled at 16 diverse emergency departments. We recorded the imaging modalities and radiographic interpretations rendered by unblinded faculty radiologists at each center. Only patients with cervical spine injury were included in this analysis. Findings revealed by individual modalities were compared with the final diagnosis (after all evaluations) in each patient. RESULTS: Six hundred eighty-eight patients with 1,302 separate cervical spine injuries were enrolled. Four hundred seventy-six (69%) patients had magnetic resonance imaging (MRI) and/or computed tomography (CT) of the cervical spine. MRI identified the following injuries among 124 imaged patients: osseous fractures, 85 of 154 (55%); spinal cord injury, 69 of 69 (100%); vertebral subluxation/dislocation, 37 of 43 (86%); ligamentous injury, 38 of 38 (100%); and unilateral/bilateral locked facets, 14 of 18 (78%). Among 418 patients undergoing CT, the following injuries were identified: osseous fractures, 721 of 740 (97%); spinal cord injury, 0 of 30 (0%); vertebral subluxation/dislocation, 76 of 88 (86%); ligamentous injury, 9 of 36 (25%); and unilateral/bilateral locked facets, 34 of 35 (97%). CT identified 29 patients with fractures who had normal plain radiographs. Cervical myelograms were obtained in two patients and cervical tomograms in seven patients. CONCLUSION: The majority of patients with cervical spine injury undergo MRI and/or CT imaging. In clinical practice, MRI is superior at identifying soft tissue injuries, whereas CT performs better in identifying bony injuries. Cervical myelograms and tomograms are rarely obtained.
OBJECTIVE: We evaluated the incidence and organ distribution of arterial extravasation identified using contrast-enhanced helical CT in patients who had sustained abdominal visceral injuries and pelvic fractures after blunt trauma. SUBJECTS AND METHODS: Five hundred sixty-five consecutive patients from four level I trauma centers who had CT scans showing abdominal visceral injuries or pelvic fractures were included in this series. The presence or absence of arterial extravasation, as well as the anatomic sites of arterial extravasation, was noted. We obtained clinical follow-up data, including surgical or angiographic findings. RESULTS: In our series, 104 (18.4%) of 565 patients had arterial extravasation. Of the 104 patients, 81 (77.9%) underwent surgery, embolization, or both. The combined rate of surgery or embolization in patients with arterial extravasation was statistically higher than expected at all four institutions (p <0.001). The spleen was the most common organ injured, occurring in 277 (49.0%) of 565 patients, and arterial extravasation occurred in 49 (17.7%) of 277 patients with splenic injury. Several other visceral injuries were associated with arterial extravasation, including hepatic, renal, adrenal, and mesenteric injuries. CONCLUSION: Based on the limited reports of arterial extravasation in the nonhelical CT literature, the percentage (18%) of clinically stable patients in our study with CT scans showing arterial extravasation was higher than anticipated. This finding likely reflects the improved diagnostic capability of helical CT. Although the spleen and liver were the organs most commonly associated with arterial extravasation, radiologists should be aware that arterial extravasation may be associated with several other visceral injuries.