Jennifer W. Uyeda

CT Angiography in Trauma

Rapid assessment and diagnosis of traumatic arterial injuries are critical in the evaluation of acutely injured patients. CT angiograms (CTAs) have become common imaging methods in busy trauma centers. CTA has largely replaced digital subtraction angiography because of its speed, noninvasive nature, accuracy, and widespread availability. This article reviews the current use of multidetector CTA in trauma with attention to technique and protocol considerations, illustrates findings of many commonly encountered injuries, and discusses the clinical implications of vascular trauma throughout the body.

Integration of 64-Detector Lower Extremity CT Angiography into Whole-Body Trauma Imaging: Feasibility and Early Experience

PURPOSE To evaluate the image quality and clinical utility of a polytrauma computed tomographic (CT) protocol that integrates lower extremity CT angiography into multiphasic whole-body trauma CT by utilizing 64-detector CT and a single contrast material bolus. MATERIALS AND METHODS This retrospective study was institutional review board approved and HIPAA compliant. Informed consent was waived. All patients who underwent CT angiography of the lower extremities integrated with multiphasic torso CT for trauma between May 2005 and September 2009 were included. Two hundred eighty-four patients met the inclusion criteria. The mechanism of trauma was blunt injury in 228 (80.3%) of 284 patients and penetrating in 56 (19.7%) of 284 patients. CT angiography encompassed the joints proximal and distal to the injured region, with scan delay fixed at 25 seconds. Two radiologists retrospectively reviewed all the extremity CT angiograms, noting the presence of vascular injury, and measured the attenuation in the lower extremity arteries. Arterial attenuation, in Hounsfield units, was measured at multiple vascular divisions, and CT angiographic results were compared with clinical outcome, and if available, repeat lower extremity CT angiographic, conventional angiographic, or surgical findings. Sensitivity and specificity with 95% confidence intervals were calculated. RESULTS Sixty-three arterial injuries were identified in 44 (15.5%) of 284 patients as follows: occlusion (n = 37), narrowing (n = 9), active extravasation (n = 14), pseudoaneurysm (n= 2), and arteriovenous fistula (n = 1). Three patients underwent conventional angiography after CT angiography. Seven patients underwent surgical therapy with all CT angiographic findings confirmed. There were no injuries subsequently identified in the subgroup with a negative result at CT angiography. Of the 864 vascular divisions in which attenuation was measured, 69 (8%) of 864 had a mean attenuation less than 150 HU. CONCLUSION Integration of lower extremity CT angiography into multiphasic whole-body trauma imaging is feasible, helps detect clinically relevant vascular injuries, and results in diagnostic image quality in the majority of patients.

Active Hemorrhage and Vascular Injuries in Splenic Trauma: Utility of the Arterial Phase in Multidetector CT

PURPOSE To determine whether the addition of arterial phase computed tomography (CT) to the standard combination of portal venous and delayed phase imaging increases sensitivity in the diagnosis of active hemorrhage and/or contained vascular injuries in patients with splenic trauma. MATERIALS AND METHODS The institutional review board approved this HIPAA-compliant retrospective study; the requirement to obtain informed consent was waived. The study included all patients aged 15 years and older who sustained a splenic injury from blunt or penetrating trauma and who underwent CT in the arterial and portal venous phases of image acquisition during a 74-month period (September 2005 to November 2011). CT scans were reviewed by three radiologists, and a consensus interpretation was made to classify the splenic injuries according to the American Association for the Surgery of Trauma splenic injury scale. One radiologist independently recorded the presence of contained vascular injuries or active hemorrhage and the phase or phases at which these lesions were seen. Clinical outcome was assessed by reviewing medical records. The relationship between imaging findings and clinical management was assessed with the Fisher exact test. RESULTS One hundred forty-seven patients met the inclusion criteria; 32 patients (22%) had active hemorrhage and 22 (15%) had several contained vascular injuries. In 13 of the 22 patients with contained injuries, the vascular lesion was visualized only at the arterial phase of image acquisition; the other nine contained vascular injuries were seen at all phases. Surgery or embolization was performed in 11 of the 22 patients with contained vascular injury. CONCLUSION The arterial phase of image acquisition improves detection of traumatic contained splenic vascular injuries and should be considered to optimize detection of splenic injuries in trauma with CT.

A Quantitative Comparison of Noise Reduction Across Five Commercial (Hybrid and Model-Based) Iterative Reconstruction Techniques: An Anthropomorphic Phantom Study

OBJECTIVE. The objective of our study was to compare the performance of three hybrid iterative reconstruction techniques (IRTs) (ASiR, iDose4, SAFIRE) and their respective strengths for image noise reduction on low-dose CT examinations using filtered back projection (FBP) as the standard reference. Also, we compared the performance of these three hybrid IRTs with two model-based IRTs (Veo and IMR) for image noise reduction on low-dose examinations. MATERIALS AND METHODS. An anthropomorphic abdomen phantom was scanned at 100 and 120 kVp and different tube current-exposure time products (25-100 mAs) on three CT systems (for ASiR and Veo, Discovery CT750 HD; for iDose4 and IMR, Brilliance iCT; and for SAFIRE, Somatom Definition Flash). Images were reconstructed using FBP and using IRTs at various strengths. Nine noise measurements (mean ROI size, 423 mm(2)) on extracolonic fat for the different strengths of IRTs were recorded and compared with FBP using ANOVA. Radiation dose, which was measured as the volume CT dose index and dose-length product, was also compared. RESULTS. There were no significant differences in radiation dose and image noise among the scanners when FBP was used (p > 0.05). Gradual image noise reduction was observed with each increasing increment of hybrid IRT strength, with a maximum noise suppression of approximately 50% (48.2-53.9%). Similar noise reduction was achieved on the scanners by applying specific hybrid IRT strengths. Maximum noise reduction was higher on model-based IRTs (68.3-81.1%) than hybrid IRTs (48.2-53.9%) (p < 0.05). CONCLUSION. When constant scanning parameters are used, radiation dose and image noise on FBP are similar for CT scanners made by different manufacturers. Significant image noise reduction is achieved on low-dose CT examinations rendered with IRTs. The image noise on various scanners can be matched by applying specific hybrid IRT strengths. Model-based IRTs attain substantially higher noise reduction than hybrid IRTs irrespective of the radiation dose.

ACR Appropriateness Criteria® Acute Pelvic Pain in the Reproductive Age Group.

Acute pelvic pain in premenopausal women frequently poses a diagnostic dilemma. These patients may exhibit nonspecific signs and symptoms such as nausea, vomiting and leukocytosis. The cause of pelvic pain includes a myriad of diagnostic possibilities such as obstetric, gynecologic, urologic, gastrointestinal, and vascular etiologies. The choice of the imaging modality is usually determined by a suspected clinical differential diagnosis. Thus the patient should undergo careful evaluation and the suspected differential diagnosis should be narrowed before an optimal imaging modality is chosen. Transvaginal and transabdominal pelvic sonography is the modality of choice, to assess for pelvic pain, when an obstetric or gynecologic etiology is suspected and computed tomography is often more useful when gastrointestinal or genitourinary pathology is thought to be more likely. Magnetic resonance imaging, when available in the acute setting, is favored over computed tomography for assessing pregnant patients for nongynecologic etiologies owing to its lack of ionizing radiation.The American College of Radiology 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 where evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

Actinomycosis in the mandible: CT and MR findings.

SUMMARY: Mandibular actinomycosis is an uncommon disease. We retrospectively reviewed 6 patients with pathologically proven mandibular actinomycosis who underwent both CT and MR imaging to evaluate the characteristic imaging findings. CT results showed an irregularly marginated lesion with increased bone marrow attenuation, osteolysis, and involvement of the skin in all patients. Periosteal reaction and intralesional gas were seen in 4 patients. MR imaging results revealed low signal on T1-weighted and high signal on T2-weighted images of the mandible, and moderate heterogeneous enhancement was seen in all patients who received intravenous contrast. Cervical lymphadenopathy was not observed. Involvement of the masseter, lateral pterygoid, and medial pterygoid muscles was seen in 4 patients, whereas parotid gland and submandibular gland as well as parapharyngeal space involvement were seen in 3 patients. Familiarity with the imaging findings of mandibular actinomycosis may help to diagnosis this entity.

Case records of the Massachusetts General Hospital. Case 2-2015. A 25-year-old man with abdominal pain, syncope, and hypotension.

Dr. Albert Yeh (Medicine): A 25-year-old man was admitted to this hospital because of abdominal pain, syncope, and hypotension. The patient had been well on the day of admission until, while lifting heavy boxes with a friend, he suddenly felt “a warm feeling” diffusely and had discomfort in his epigastrium and right upper quadrant that radiated throughout his abdomen, followed by tingling in his mouth, tongue, arms, and legs. Within the next few minutes, his vision blurred and darkened. He felt faint and lay down on the sidewalk. Within 5 minutes after the onset of symptoms, nonbloody, nonbilious vomiting occurred, and he lost consciousness. His friend held him in a sitting position and noticed he was shaking. Emergency medical services were called. On examination by emergency medical services personnel, the patient was lying on the sidewalk, unresponsive to verbal or painful stimuli, and had diaphoresis, shallow breathing, a clenched jaw, and urinary incontinence. A nasopharyngeal airway was placed, high-flow oxygen was administered, and ventilation with a bag-valve mask was performed at a rate of 10 breaths per minute. The Glasgow Coma Scale score was 3 (on a scale of 3 to 15, with lower scores indicating reduced levels of consciousness). The blood pressure was 53/27 mm Hg, and the pulse 90 beats per minute. A cardiac monitor recorded normal sinus rhythm. A bolus of normal saline was rapidly infused. Within 3 minutes, the pulse rose to 118 beats per minute, the blood pressure rose to 60/28 mm Hg, and spontaneous respirations resumed; high-flow oxygen was administered through a nonrebreather face mask. The level of capillary blood glucose was 73 mg per deciliter (4.05 mmol per liter). Naloxone was administered intravenously, without improvement. During transport to this hospital by ambulance, the patient opened his eyes in response to verbal stimuli. The blood pressure transiently rose to 102/73 mm Hg and then fell to 83/31 mm Hg, the pulse was 90 beats per minute, the respiratory rate was 17 to 21 breaths per minute, and the Glasgow Coma Scale score rose to 9. On arrival in the emergency department, approximately 30 minutes after the onset of symptoms, the patient was initially difficult to arouse, but his condition rapidly improved and then he was alert and responsive. He reported abdominal pain, which From the Departments of Medicine (M.R.M.), Radiology (J.W.U.), and Pa‐ thology (B.T.), Massachusetts General Hospital, and the Departments of Medi‐ cine (M.R.M.), Radiology (J.W.U.), and Pathology (B.T.), Harvard Medical School — both in Boston.

Case 2-2015

Dr. Albert Yeh (Medicine): A 25-year-old man was admitted to this hospital because of abdominal pain, syncope, and hypotension. The patient had been well on the day of admission until, while lifting heavy boxes with a friend, he suddenly felt “a warm feeling” diffusely and had discomfort in his epigastrium and right upper quadrant that radiated throughout his abdomen, followed by tingling in his mouth, tongue, arms, and legs. Within the next few minutes, his vision blurred and darkened. He felt faint and lay down on the sidewalk. Within 5 minutes after the onset of symptoms, nonbloody, nonbilious vomiting occurred, and he lost consciousness. His friend held him in a sitting position and noticed he was shaking. Emergency medical services were called. On examination by emergency medical services personnel, the patient was lying on the sidewalk, unresponsive to verbal or painful stimuli, and had diaphoresis, shallow breathing, a clenched jaw, and urinary incontinence. A nasopharyngeal airway was placed, high-flow oxygen was administered, and ventilation with a bag-valve mask was performed at a rate of 10 breaths per minute. The Glasgow Coma Scale score was 3 (on a scale of 3 to 15, with lower scores indicating reduced levels of consciousness). The blood pressure was 53/27 mm Hg, and the pulse 90 beats per minute. A cardiac monitor recorded normal sinus rhythm. A bolus of normal saline was rapidly infused. Within 3 minutes, the pulse rose to 118 beats per minute, the blood pressure rose to 60/28 mm Hg, and spontaneous respirations resumed; high-flow oxygen was administered through a nonrebreather face mask. The level of capillary blood glucose was 73 mg per deciliter (4.05 mmol per liter). Naloxone was administered intravenously, without improvement. During transport to this hospital by ambulance, the patient opened his eyes in response to verbal stimuli. The blood pressure transiently rose to 102/73 mm Hg and then fell to 83/31 mm Hg, the pulse was 90 beats per minute, the respiratory rate was 17 to 21 breaths per minute, and the Glasgow Coma Scale score rose to 9. On arrival in the emergency department, approximately 30 minutes after the onset of symptoms, the patient was initially difficult to arouse, but his condition rapidly improved and then he was alert and responsive. He reported abdominal pain, which From the Departments of Medicine (M.R.M.), Radiology (J.W.U.), and Pa‐ thology (B.T.), Massachusetts General Hospital, and the Departments of Medi‐ cine (M.R.M.), Radiology (J.W.U.), and Pathology (B.T.), Harvard Medical School — both in Boston.

Sarcopenia increases risk of long-term mortality in elderly patients undergoing emergency abdominal surgery

BACKGROUND Frailty is associated with poor surgical outcomes in elderly patients but is difficult to measure in the emergency setting. Sarcopenia, or the loss of lean muscle mass, is a surrogate for frailty and can be measured using cross-sectional imaging. We sought to determine the impact of sarcopenia on 1-year mortality after emergency abdominal surgery in elderly patients. METHODS Sarcopenia was assessed in patients 70 years or older who underwent emergency abdominal surgery at a single hospital from 2006 to 2011. Average bilateral psoas muscle cross-sectional area at L3, normalized for height (Total Psoas Index [TPI]), was calculated using computed tomography. Sarcopenia was defined as TPI in the lowest sex-specific quartile. Primary outcome was mortality at 1 year. Secondary outcomes were in-hospital mortality and mortality at 30, 90, and 180 days. The association of sarcopenia with mortality was assessed using Cox proportional hazards regression and model performance judged using Harrells C-statistic. RESULTS Two hundred ninety-seven of 390 emergency abdominal surgery patients had preoperative imaging and height. The median age was 79 years, and 1-year mortality was 32%. Sarcopenic and nonsarcopenic patients were comparable in age, sex, race, comorbidities, American Society of Anesthesiologists classification, procedure urgency and type, operative severity, and need for discharge to a nursing facility. Sarcopenic patients had lower body mass index, greater need for intensive care, and longer hospital length of stay (p < 0.05). Sarcopenia was independently associated with increased in-hospital mortality (risk ratio, 2.6; 95% confidence interval [CI], 1.6–3.7) and mortality at 30 days (hazard ratio [HR], 3.7; 95% CI, 1.9–7.4), 90 days (HR, 3.3; 95% CI, 1.8–6.0), 180 days (HR, 2.5; 95% CI, 1.4–4.4), and 1 year (HR, 2.4; 95% CI, 1.4–3.9). CONCLUSION Sarcopenia is associated with increased risk of mortality over 1 year in elderly patients undergoing emergency abdominal surgery. Sarcopenia defined by TPI is a simple and objective measure of frailty that identifies vulnerable patients for improved preoperative counseling, setting realistic goals of care, and consideration of less invasive approaches. LEVEL OF EVIDENCE Prognostic study, level III.

Evaluation of Acute Abdominal Pain in the Emergency Setting Using Computed Tomography Without Oral Contrast in Patients With Body Mass Index Greater Than 25.

Purpose To evaluate the rate of delayed or missed diagnoses and need for additional computed tomography (CT) imaging in emergency department patients with abdominal pain who are imaged without oral contrast. Materials and Methods The institutional review board approved this Health Insurance Portability and Accountability Act-compliant retrospective study; informed consent was waived. All consecutive adult patients with body mass index greater than 25 undergoing a CT abdomen/pelvis with intravenous contrast and without oral contrast with nontraumatic acute abdominal pain during a 16-month period at our academic tertiary care center were included. Medical records were reviewed, imaging findings on admission CT, use of repeat CT examinations within 4 weeks of the original examination, and clinical outcomes were recorded. In patients undergoing repeat imaging, an investigator determined whether repeat imaging was influenced by the lack of oral contrast on the original examination. As the most common cause of bowel-related positive CT scans, an analysis of acute appendicitis was performed. Results Of the 1992 patients included in this study, 4 patients (0.2%) underwent repeat CT studies directly related to the absence of oral contrast on the original examination. Of the 1992 CT scans, 1193(59.8%) were interpreted as negative, none of which required surgery or direct intervention. In patients with acute appendicitis, there was a sensitivity of CT in this patient population of 100% with a specificity of 99.5%. Conclusions In patients with body mass index greater than 25 presenting to the ED with acute abdominal pain, CT examinations can be acquired without oral contrast without compromising the clinical efficacy of CT.