Computed tomography (CT) with and without contrast: indications and protocols. An official website of the United States government. Careers. It results in pain, erythema, oedema, and warmth. JAMES V. RAWSON, MD, AND ALLEN L. PELLETIER, MD. Struk DW, Munk PL, Lee MJ, Ho SG, Worsley DF. 2009;16(4):267-76. Federal government websites often end in .gov or .mil. If youre a nurse practitioner who struggles with the same question, check out the following guide to contrast and CT scans. Thirteen orbital computed tomographic (CT) scans were obtained in 12 patients with postseptal (orbital) cellulitis. Clear communication between the physician and radiologist is essential for obtaining the most appropriate study at the lowest cost and risk to the patient. MRI's visualization of the bone marrow allows for the sensitive detection of osteomyelitis, although specificity for the diagnosis of osteomyelitis is aided by other findings, including cortical destruction. Epub 2015 Apr 29. Extensive streaky soft-tissue gas is seen extending along the fascial planes of the right thigh on radiograph. Mitchell C, Dolan N, Drsteler K. Management of Dependent Use of Illicit Opioids. Necrotizing fasciitis: early sonographic diagnosis. Hayeri MR, Ziai P, Shehata ML, Teytelboym OM, Huang BK. My answer is based on the current radiologic practices and terminology employed in the U.S. 1. At our institution, the CT protocol includes concomitant injections in the upper-extremity veins, with imaging timed for venous phase enhancement (pulmonary venogram). 07/16 RH /MF 9. Nonanaphylactoid reactions are dependent on contrast osmolality and on the volume and route of injection (unlike anaphylactoid reactions).10 Typical symptoms include warmth, metallic taste, and nausea or vomiting. Postoperative sternal wound infections are not uncommon and range from cellulitis to frank osteomyelitis. The purpose of this article is to review the imaging findings of necrotizing fasciitis as seen on radiograph, ultrasound, CT, and MRI, and to recognize the early findings in this potentially fatal disease. CT without contrast in a patient with a history of interstitial lung disease and right lung transplant shows the patent but partially narrowed anastomotic site of the right bronchus (A) (red arrow). Children have a lower incidence of reactions to IV contrast agents, and most of these are mild (0.18% for low-osmolality agents).7,8, Risk factors for contrast reactions include multiple drug allergies and asthma. Horton L, Jacobson J, Powell A, Fessell D, Hayes C. Sonography and Radiography of Soft-Tissue Foreign Bodies. Saad A, Kho J, Almeer G, Azzopardi C, Botchu R. Br J Radiol. This question is for testing whether or not you are a human visitor and to prevent automated spam submissions. MRI Nomenclature for Musculoskeletal Infection. Bookshelf Reference article, Radiopaedia.org (Accessed on 01 May 2023) https://doi.org/10.53347/rID-15554. Cross-sectional imaging findings include asymmetric thickening of the fascia, soft-tissue air, blurring of fascial planes, inflammatory fat stranding, reactive lymphadenopathy, and nonenhancement of the muscular fascia. 2001;176(5):1155-9. CT Exams Contrast vs Non-Contrast Guide These suggestions are general guidelines that apply to the use of contrast for CT exams provided at Oregon Imaging Centers. The .gov means its official. No mutagenic or teratogenic effects have been shown with nonionic, low-osmolality contrast in animal studies. Fasciae of the Musculoskeletal System: MRI Findings in Trauma, Infection and Neoplastic Diseases. 8. Spinnato P, Patel DB, Di Carlo M, Bartoloni A, Cevolani L, Matcuk GR, Cromb A. Microorganisms. Emerg Radiol. Recent studies suggest that a combination of hydration, sodium bicarbonate, N-acetylcysteine, and decreased contrast volume may reduce this risk in high-risk populations.14,15, The question of whether this risk has been overstated has been raised in the medical literature. National Library of Medicine Most centers use nonionic contrast agents (which are generally low osmolality) for IV contrast studies.5 The rate of major reactions (e.g., anaphylaxis, death) is the same for ionic and nonionic IV contrast agentsan estimated one in 170,000 administrationsbut nonionic contrast has a lower rate of minor reactions.6 Approximately 5% to 12% of patients who receive high-osmolality contrast have adverse reactions, most of which are mild or moderate.7 Use of low-osmolality contrast has been associated with a reduction in adverse effects. Rahmouni A, Chosidow O, Mathieu D et al. Address correspondence to: Dr David K Tso. Weaver JS, Omar IM, Mar WA, Klauser AS, Winegar BA, Mlady GW, McCurdy WE, Taljanovic MS. Pol J Radiol. Radiologic Approach to Musculoskeletal Infections. Contrast agents can be further classified as high or low osmolality, based on the iodine concentration. Although many radiology departments screen for shellfish allergy, there is no cross-reactivity between shellfish and iodinated contrast. 2001;176(5):1155-9. It is injected through an intravenous line during the examination. In general, oral contrast is used for most abdominal and pelvic CT scans unless there is no suspicion of bowel pathology (e.g., noncontrast CT to detect kidney stones) or when administration. 8600 Rockville Pike Speak with a Radiologist: 541-284-4016 Contrast materials are generally safe; however, as with any pharmaceutical, there is the potential for adverse reactions. Your email address will not be published. Insights Imaging. 2 0 obj Computed tomography (CT) plays an important role in the diagnosis and treatment of many clinical conditions1 involving the chest wall, mediastinum, pleura, pulmonary arteries, and lung parenchyma. There are several contrast agents that may be used in performing CT scans. Fasciae of the Musculoskeletal System: MRI Findings in Trauma, Infection and Neoplastic Diseases. CT Angiography, or CTA, is a type of contrasted CT scan used to evaluate the blood vessels. Interstitial lung disease 2. The concentration of barium used for fluoroscopy is more than 20 times that of the typical oral contrast suspension for CT. For example, the barium concentration from an upper gastrointestinal series or an enema will produce an artifact on abdominal CT because it is significantly more concentrated than bowel contrast agents used for CT. Barium enemas are also given after abdominal CT to allow time for the less-dense barium to leave the colon. CT is commonly used to diagnose, stage, and plan treatment for lung cancer, other primary neoplastic processes involving the chest, and metastatic disease.2 The need for contrast varies on a case-by-case basis, and the benefits of contrast should be weighed against the potential risks in each patient. no financial relationships to ineligible companies to disclose. HHS Vulnerability Disclosure, Help When does chest CT require contrast enhancement? What is the rationale for the laboratory workup for suspected pheochromocytomas and paragangliomas? AJR Am J Roentgenol. Abdominal and/or pelvic pain-acute or chronic 2. Axial non-contrast. Clear communication between the physician and radiologist is essential for obtaining the most appropriate study at the lowest cost and risk to the patient. CT pulmonary angiography with intravenous contrast in a patient being evaluated for arteriovenous malformation. The most common are baruim and iodine based. Data Sources: We used the term radiologic contrast to search the following: PubMed Clinical Queries (systematic reviews); the OVID database (all evidence-based medicine reviews; Cochrane Database of Systematic Reviews, ACP Journal Club, Database of Abstracts of Reviews of Effects, Cochrane Central Trial Registry, Cochrane Methodology Register, Health Technology Assessment, and NHS Economic Effectiveness Database); Dynamed; and the U.S. Preventive Services Task Force and Agency for Healthcare Research and Quality clinical guidelines and evidence reports. 1998;170(3):615-20. dobrien 2015;2015:587857. doi: 10.1155/2015/587857. Patients with a mild allergy may be pre-medicated with an antihistamine or steroids before imaging. Wall DB, Klein SR, Black S, de Virgilio C. A simple model to help distinguish necrotizing fasciitis from nonnecrotizing soft tissue infection. Because there is a risk of aspiration-induced pulmonary edema with concentrated iodine-based contrast agents, patients must be carefully selected. 2022 Nov 25;10(12):2329. doi: 10.3390/microorganisms10122329. PMC Family physicians often must determine the most appropriate diagnostic tests to order for their patients. 3 1Department of Radiology, Massachusetts General Hospital, Boston, MA, USA. Sagittal CT reformation demonstrates linear fluid collection (arrow) deep to the rectus femoris muscle (b). A 45-year-old male with necrotizing fasciitis of the right thigh. Kidney/ureteral stones With IV contrast 1. Federal government websites often end in .gov or .mil. Muscular fascia lies deep to the subcutaneous layer. Dr. Amy Levine answered. ADVERTISEMENT: Radiopaedia is free thanks to our supporters and advertisers. Copyright 2013 by the American Academy of Family Physicians. official website and that any information you provide is encrypted A paranasal sinus pathology is . If the infection spreads to deeper tissues, soft-tissue abscess, infectious myositis, necrotizing fasciitis, and osteomyelitis can all be detected with CT. MRI is sensitive for distinguishing cellulitis alone from necrotizing fasciitis and infectious myositis and for showing subcutaneous fluid collections and abscesses. Oral contrast is generally used for visualization of the abdomen and/or pelvis when there is suspicion of bowel pathology. Ultrasonographic screening of clinically-suspected necrotizing fasciitis. AJR Am J Roentgenol. The most common contrast agents used with CT imaging are barium- and iodine-based. Brothers TE, Tagge DU, Stutley JE, Conway WF, Del Schutte H, Byrne TK. Symptoms typically disappear a few . Cellulitis. It results in pain, erythema, oedema, and warmth. The U.S. Food and Drug Administration advises that metformin should be withheld at the time of IV contrast administration and for 48 hours afterward, and resumed only after reevaluation of renal status (i.e., return to baseline serum creatinine level).13. One of these questions that came up frequently related to CT scans was Do I need contrast?. Epub 2017 Mar 30. Renal function should be assessed with a baseline creatinine level before administration as patients with impaired renal function are at risk for complications associated with IV contrast. Paz Maya S, Dualde Beltrn D, Lemercier P, Leiva-Salinas C. Necrotizing fasciitis: an urgent diagnosis. E-mail: Received 2018 Jan 20; Revised 2018 Mar 2; Accepted 2018 Mar 8. In the emergency setting, CT of the neck is often performed to investigate symptoms of acute infection or inflammation or symptoms of aerodigestive tract compromise referable to the neck.
