With respect to employing CT as an imaging modality, first one should be aware of the different ty. N.p. Laryngeal edema (severe or rapidly progressing), Methylprednisolone (Medrol), 32 mg orally 12 and 2 hours before contrast administration; plus diphenhydramine (Benadryl), 50 mg intravenously, intramuscularly, or orally 1 hour before contrast administration, Prednisone, 50 mg orally 13, 7, and 1 hour before contrast administration; plus diphenhydramine, 50 mg intravenously, intramuscularly, or orally 1 hour before contrast administration, Normal renal function and no comorbid disorder, Metformin (Glucophage) can be continued when contrast is administered; serum creatinine does not need to be measured, Normal renal function and at least one comorbid disorder, Metformin should be discontinued when contrast is administered; if the patient remains clinically stable and has no new intercurrent risk factors for renal impairment, metformin may be resumed in 48 hours without repeating serum creatinine measurement, Metformin should be discontinued when contrast is administered; resume only after careful reevaluation and monitoring of renal status, Noncontrast-enhanced CT of the head is the preferred initial study if performed within three hours of acute symptom onset; contrast-enhanced CT should be obtained for patients with symptoms lasting longer than three hours; contrast-enhanced CT combined with CT angiography of the neck may be needed for follow-up, Thin section high-resolution CT without contrast, Extremity soft tissue swelling, infection, or trauma, Contrast is necessary if vascular involvement or injury is suspected, Scan suspected area of trauma in cervical, thoracic, or lumbar spine, Abdominal and pelvic CT; oral or rectal contrast agent based on institutional preference, Protocols vary depending on cancer type and stage, Diverticulitis; suspected complications of inflammatory bowel disease, Intravenous contrast agent for diverticulitis; oral and/or rectal contrast agent can be administered to visualize bowel, Noncontrast-enhanced CT is sensitive for calcifications (chronic pancreatitis); contrast-enhanced CT is best for evolving pancreatitis or pancreatic pseudocyst, Many centers now include venous phase CT of the pelvis and lower extremities in combination with CT angiography of the lung. Inflammatory cellulitis is frequently confused with infectious cellulitis. Thirteen orbital computed tomographic (CT) scans were obtained in 12 patients with postseptal (orbital) cellulitis. 1998;170(3):615-20. AJR Am J Roentgenol. A 39-year-old-male with necrotizing fasciitis of the right thigh. 1Department of Radiology, Massachusetts General Hospital, Boston, MA, USA. Computed tomography (CT scan or CAT scan) is a noninvasive diagnostic imaging procedure that uses a combination of X-rays and computer technology to produce horizontal, or axial, images (often called slices) of the body. Additionally, systemic features such as fevers and rigors may also be present. There is subcutaneous emphysema (arrows) overlying the right ankle with plate and screw fixation seen (a). That said, it is seldom required for diagnosing cellulitis and is therefore usually ordered for suspected complications or to rule out alternative diagnoses in cases of an atypical presentation. T2 weighted images with fat saturation demonstrates extensive high signal within the intermuscular septa surrounding the gastrocnemius and soleus muscle bellies suggestive of subfascial fluid (white arrows). Dr. Amy Levine answered. Pulmonary embolic disease is the third most common cause of acute car diovascular disease.5 CT pulmonary angiography is the most common way to assess for pulmonary embolic disease, as it is accurate, fast, and widely available, and can assess alternate pathologies in cases of undifferentiated chest pain. Copyright 2023 American Academy of Family Physicians. The PubMed wordmark and PubMed logo are registered trademarks of the U.S. Department of Health and Human Services (HHS). Epub 2020 Oct 15. 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. Schmid M, Kossmann T, Duewell S. Differentiation of Necrotizing Fasciitis and Cellulitis Using MR Imaging. Skin findings, pain out of proportion, and signs of systemic shock should alert the clinician to the possibility of necrotizing fasciitis. In certain situations, however, a contrast medium is essential. 6. In uncomplicated cellulitis, CT demonstrates skin thickening, septation of the subcutaneous fat, and thickening of the underlying superficial fascia. Creatinine cutoffs vary among institutions, but generally range between 1.5 and 2 mg per dL (132.6 to 176.8 mol per L) before alternative imaging strategies are considered.7 An increasing creatinine level that is still within normal limits is also concerning, and alternative imaging strategies should be considered. This material may not otherwise be downloaded, copied, printed, stored, transmitted or reproduced in any medium, whether now known or later invented, except as authorized in writing by the AAFP. Potential Harms of Computed Tomography: The Role of Informed Consent. Kidney/ureteral stones With IV contrast 1. Recent estimates place the number of computed tomography (CT) scans performed annually in the United States at approximately 70 million.1 Given the cost and radiation exposure, it is critical that CT is appropriate and performed with optimal technique. N/A No CT WRIST LEFT WO CONTRAST (IMG3906) CT WRIST RIGHT WO CONTRAST(IMG3909) CT HAND LEFT WO CONTRAST (IMG3794) CT HAND RIGHT WO CONTRAST (IMG3797) 73200 Contrast agents can be further classified as high or low osmolality, based on the iodine concentration. Cellulitis (rare plural: cellulitides) is an acute infection of the dermis and subcutaneous tissues without deep fascial or muscular involvement. Clinical presentations include skin erythema without a well-defined border, increased skin temperature, swelling of the affected area, and regional lymphadenopathy and lymphangitis. Check for errors and try again. One of these questions that came up frequently related to CT scans was Do I need contrast?. This question is for testing whether or not you are a human visitor and to prevent automated spam submissions. government site. Biomed Res Int. % Thank you for your interest in spreading the word on Cleveland Clinic Journal of Medicine. MR Imaging in Acute Infectious Cellulitis. 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. Gk MC, Turhan Y, Demirolu M, Kl B, Akku M, zkan K. Radiological assessment in necrotizing fasciitis. Insights Imaging. A 45-year-old male with necrotizing fasciitis of the right thigh. The American Academy of Radiology recommends the use of IV contrast only if care of the patient cannot be accomplished without it. Contrast agents are used to differentiate between organs and improve lesion detection and characterization. Copyright2022 ThriveAP Inc., All Rights Reserved, Key Advice for NPs & PAs with Angela Golden, DNP, FNP-C, FAANP, FOMA, Evidence-Based Wound Care for Advanced Practice Providers, Featured ThriveAP Faculty: Benjamin Smith, DMSc, PA-C, DFAAPA, Finding Your Why with ThriveAP Speaker Steven Wei, EdD, MPH, MS, PA-C, DFAAPA. A 55-year-old male with necrotizing Fasciitis of the left thigh. In Vivo MicroCT Monitoring of Osteomyelitis in a Rat Model. endobj official website and that any information you provide is encrypted It is injected through an intravenous line during the examination. 30 0 obj 3 BMJ. Ultrasound is usually the first investigation to evaluate a clinical suspicion of cellulitis. 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. These agents are not used for imaging of the abdomen and/or pelvis if bowel pathology is not suspected, or if doing so will delay scanning as in the case of acute trauma. 2009;39(10):957-71. Disease processes that involve calcifications may benefit from noncontrast-enhanced images because contrast may mask the appearance of calcifications. Diagnosis of necrotizing soft tissue infections by computed tomography. One study showed similar increases in serum creatinine levels between inpatient populations who received IV iodinated contrast and those who did not.16, Noncontrast-enhanced CT is used in patients with head trauma and acute stroke. Postoperative sternal wound infections are not uncommon and range from cellulitis to frank osteomyelitis. Fasciae of the Musculoskeletal System: MRI Findings in Trauma, Infection and Neoplastic Diseases. endstream 2017 Jun;31(2):299-324. doi: 10.1016/j.idc.2017.01.004. 2019;10(1):47. This content is owned by the AAFP. Orbital cellulitis is an infectious process affecting the muscles and fat within the orbit, posterior or deep to the orbital septum, not involving the globe. Citation, DOI, disclosures and article data. Reference article, Radiopaedia.org (Accessed on 01 May 2023) https://doi.org/10.53347/rID-15554. If the infection spreads to deeper tissues, complications can occur, such as soft-tissue abscess,necrotising fasciitis,infectious myositis, and/or osteomyelitis. IV dye may cause a temporary alteration in kidney function. MR Imaging in Acute Infectious Cellulitis. 2007 Nov-Dec;27(6):1723-36. doi: 10.1148/rg.276075033. CT may also be ordered for cross-sectional images of the spine with contrast in the thecal sac. Radiologic Approach to Musculoskeletal Infections. Diffuse high signal can also be seen in the muscle and subcutaneous fat.13 If subcutaneous edema is not the predominant feature, one should consider necrotizing fasciitis rather than cellulitis.1, 13 A summary of spectrum of findings for necrotizing fasciitis is summarized in Figure 10 and Table 2. Copyright 2016 The Cleveland Clinic Foundation. Cellulitis occurs after disruption of the skin and invasion of the subcutaneous tissues by microorganisms that may be skin flora, such as beta-haemolytic streptococci (most often),Staphylococcus aureus(including methycillin-resistant), or other bacteria 9. Zacharias N, Velmahos GC, Salama A, Alam HB, de Moya M, King DR, et al.. 8600 Rockville Pike These agents for enhancing the image created on CT may be delivered by a number of different routes, the most common of which are oral and intravenous. 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. Occasionally sepsis may result. During the injection you may feel flushed and get a metallic taste in your mouth. Schmid M, Kossmann T, Duewell S. Differentiation of Necrotizing Fasciitis and Cellulitis Using MR Imaging. 8600 Rockville Pike 2001;176(5):1155-9. T2 weighted image with fat saturation of the left thigh demonstrates a large area of myonecrosis within the proximal rectus femoris muscle, with extensive muscular, fascial, and subcutaneous enhancement and edema, with crescentic fascial fluid collections, predominantly around the rectus femoris and sartorius, suggestive of necrotizing fasciitis. of 20 consecutive patients with necrotizing fasciitis, CT revealed fascial thickening and fat stranding in 80%, soft tissue gas in 55%, and abscesses in 35%.22, CT is helpful in guiding surgical debridement and drainage by evaluating the extent of soft tissue and osseous involvement, identifying the potential infectious source and identifying potential complications including vascular rupture or tissue necrosis.1, 2,13,22, MRI is the gold-standard for soft-tissue infections as it provides excellent soft-tissue contrast resolution with a sensitivity of 93% for the diagnosis for necrotizing fasciitis.1, 24 Essential sequences include T1 weighted imaging to assess anatomy, and T2 fat saturated or short tauinversion-recovery sequences to look for fascial thickening and edema.3, 25 Post gadolinium sequences are helpful to delineate the extent of infection, identify abscesses and areas of necrosis, but may not be feasible in patients with acute renal failure, which is common in this patient population.3, 26, Deep fascial thickening and subfascial fluid accumulation can be seen as high signal on fluid sensitive sequences (Figures 8 and 9).21 The deep intramuscular fascia is usually protected in the setting of cellulitis, but is involved in necrotizing fasciitis.1 Fascial thickening begins in the superficial fascia and extends along the deep intermuscular fascia, not just in areas contiguous to the deep peripheral fascia.1, 18 Hyperintensity and thickness of the fascia greater than or equal to 3 mm on fat saturated T2 weighted or short tauinversion-recovery images with involvement of three or more compartments is a sensitive finding to suggest necrotizing fasciitis.3, 8,13,25,27 The absence of T2 hyperintensity within the deep fascia can essentially exclude a diagnosis necrotizing fasciitis.3, 18,21. Unable to process the form. Unauthorized use of these marks is strictly prohibited. Interstitial lung disease 2. 2009;16(4):267-76. Use of this website is subject to the website terms of use and privacy policy. Oral contrast agents are barium- or iodine-based and are used for bowel opacification. 07/16 RH /MF 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. For the assessment of vascular disease, CT in most cases requires IV contrast to delineate the vessel lumen. Skeletal Radiol. A history of anaphylactic reactions would preclude IV contrast except in extreme emergencies. The major families of contrast agents are ionic and nonionic. Copyright 2023 The Cleveland Clinic Foundation. While adverse effects to the fetus have not been demonstrated with IV dye, contract does cross the placenta. The site is secure. Cellulitis can affect any region of the body, and commonly affects a lower limb. Working in the emergency department as a nurse practitioner, I order CT scans in my evaluation of patients every day. No mutagenic or teratogenic effects have been shown with nonionic, low-osmolality contrast in animal studies. Adams, James, and Erik D. Barton. At the time the article was last revised David Carroll had The site is secure. Special consideration should be given to geriatric patients, in whom cellulitis of the lower extremities is more likely to develop into thrombophlebitis. When is contrast needed for abdominal and pelvic CT? The decision to order contrast-enhanced CT is based on the clinical question being asked. This can be filled at Baystate Pharmacies at 759 Chestnut Street and 3300 Main Street as well as at many local pharmacies. However, IV radiologic contrast may cause transient alteration in renal function, which could impair metformin clearance, leading to a higher risk of metabolic acidosis. Soft-tissue infections and their imaging mimics: from cellulitis to necrotizing fasciitis, Necrotizing soft-tissue infection: diagnosis and management, Red flags for necrotizing fasciitis: a case control study, Sonographic detection of necrotizing fasciitis, Necrotizing soft tissue infections: a primary care review. Although many radiology departments screen for shellfish allergy, there is no cross-reactivity between shellfish and iodinated contrast. Order "HAND" if entire wrist and hand. All Rights Reserved. Since the epidermis is not involved, cellulitis is not transmitted by person-to-person contact. The https:// ensures that you are connecting to the Infection, inflammation, and edema of the lung parenchyma are usually well depicted on CT without contrast enhancement. Clear communication between the physician and radiologist is essential for obtaining the most appropriate study at the lowest cost and risk to the patient. <> The specific agent and route of administration are based on clinical indications and patient factors. <>stream sharing sensitive information, make sure youre on a federal Symptoms typically disappear a few . thickening of skin and superficial fascia, diffuse subcutaneous linear/reticular or ill-defined hyperintensity tending to collect at the hypodermis, contrast enhancement differentiates cellulitis from stasis oedema, areas of necrotising cellulitis do not enhance, degree of enhancement depends on the post contrast delay. 2 0 obj Uncomplicated cellulitis is usually treated conservatively with antibiotics and locally supportive measures. Speak with a Radiologist: 541-284-4016 Epub 2015 Apr 29. If youre a nurse practitioner who struggles with the same question, check out the following guide to contrast and CT scans. Turecki M, Taljanovic M, Stubbs A et al. It is essential to know the types of contrast agents, their risks, contraindications, and common clinical scenarios in which contrast-enhanced computed tomography is appropriate. Computed tomography (CT) with and without contrast: indications and protocols. 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. CT pulmonary angiography with intravenous contrast in a patient being evaluated for arteriovenous malformation. Cellulitis(rare plural: cellulitides) is an acute infection of the dermis and subcutaneous tissues without deep fascial or muscular involvement. 6. Alaia E, Chhabra A, Simpfendorfer C et al. Unable to load your collection due to an error, Unable to load your delegates due to an error. They are used for bowel opacification and are not nephrotoxic. This absorption and scattering in turn results in higher CT attenuation values, or enhancement on CT images. Struk DW, Munk PL, Lee MJ, Ho SG, Worsley DF. Summary of imaging findings of necrotizing fasciitis. Horton L, Jacobson J, Powell A, Fessell D, Hayes C. Sonography and Radiography of Soft-Tissue Foreign Bodies. The soft-tissue air deep to the fascia is seen as multiple echogenic foci (arrows) on ultrasound study (b). dobrien Wong CH, Khin LW, Heng KS, Tan KC, Low CO. Lactic acidosis has never been documented in patients with normal renal function who are receiving metformin. 2021;50(12):2319-47. Clipboard, Search History, and several other advanced features are temporarily unavailable. Clinical presentations include skin erythema without a well-defined border, increased skin temperature, swelling of the affected area, and regional lymphadenopathy and lymphangitis. Here is a summary of the indications for non-contrasted CT: Contrast helps enhance certain body structures. Yen ZS, Wang HP, Ma HM, Chen SC, Chen WJ. Patients with a mild allergy may be pre-medicated with an antihistamine or steroids before imaging. CT is helpful in guiding surgical debridement and drainage by evaluating the extent of soft tissue and osseous involvement, identifying the potential infectious source and identifying potential complications including vascular rupture or tissue necrosis.1, 2,13,22 MAGNETIC RESONANCE IMAGING 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. endobj Saad A, Kho J, Almeer G, Azzopardi C, Botchu R. Br J Radiol. Bookshelf Soft-tissue gas is seen at the lateral aspect of the left knee along the fascial planes on the radiograph. Nurse practitioners must be familiar with the contraindications for CT contrast administration. 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.
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