The US Preventive Services Task Force currently recommends low-dose CT without contrast, along with appropriate patient counseling, for patients with a history of smoking and an age range as detailed in the Task Force statement. Clipboard, Search History, and several other advanced features are temporarily unavailable. Wall DB, Klein SR, Black S, de Virgilio C. A simple model to help distinguish necrotizing fasciitis from nonnecrotizing soft tissue infection. PMC 5. Musculoskeletal infection: role of CT in the emergency department. www.acr.org/~/media/ACR/Documents/PGTS/guidelines/CT_Thoracic.pdf, www.acr.org/~/media/37D84428BF1D4E1B9A3A2918DA9E27A3.pdf, EVALUATION OF PULMONARY PARENCHYMAL DISEASE, EVALUATION OF STERNAL AND MEDIASTINAL INFECTIONS, Cleveland Clinic Center for Continuing Education. Although it is a clinical diagnosis, imaging is a powerful adjunct to facilitate early diagnosis in equivocal cases. IV contrast may be used to visualize vasculature as well as the internal organs of the abdomen and pelvis. The most common are baruim and iodine based. 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. As a library, NLM provides access to scientific literature. 2009;16(4):267-76. The major families of contrast agents are ionic and nonionic. Iodinated contrast should be avoided for two months before administration of iodine 131. A 64-year-old male with Fourniers gangrene with perforated diverticulitis. It is also not used in patients with suspected acute stroke. CT pulmonary angiography with intravenous contrast in a patient being evaluated for arteriovenous malformation. Suspected Osteomyelitis, Septic Arthritis, or Soft Tissue Infection (Excluding Spine and Diabetic Foot) Uncomplicated cellulitis is usually treated conservatively with antibiotics and locally supportive measures. It results in pain, erythema, oedema, and warmth. Abdominal and/or pelvic pain-acute or chronic 2. In uncomplicated cellulitis, CT demonstrates skin thickening, septation of the subcutaneous fat, and thickening of the underlying superficial fascia. The diagnostic algorithm for lung cancer screening is evolving. See permissionsforcopyrightquestions and/or permission requests. National Library of Medicine Cellulitis. Even in osseous infection, CT and MRI can give better anatomic delineation of the extent of infection. Imaging of Musculoskeletal Soft Tissue Infections. 7. In C, the transplanted lung is notable for areas of air trapping in the right upper lobe on expiratory images (blue arrow), which is associated with central airway narrowing. Kirchgesner T, Tamigneaux C, Acid S et al. 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. 3. Yu J & Habib P. MR Imaging of Urgent Inflammatory and Infectious Conditions Affecting the Soft Tissues of the Musculoskeletal System. Sign In to Email Alerts with your Email Address. 8. This absorption and scattering in turn results in higher CT attenuation values, or enhancement on CT images. Within three days of starting an antibiotic, let your health care provider know whether the infection is responding to treatment. no financial relationships to ineligible companies to disclose. Schmid M, Kossmann T, Duewell S. Differentiation of Necrotizing Fasciitis and Cellulitis Using MR Imaging. <> 2001;176(5):1155-9. Given that metformin is excreted through the kidneys, IV contrast may impair metformin clearance from the body putting the patient at risk for metabolic acidosis. In B, the native left lung is small, with evidence of bronchiectasis, bronchiolectasis, and areas of honeycombing (black arrow). 2022 Nov 25;10(12):2329. doi: 10.3390/microorganisms10122329. Insights Imaging. no financial relationships to ineligible companies to disclose. government site. 2001 Oct;42(4-5):259-305. Contrast-enhanced CT demonstrates air (arrows) and edema in the scrotum, surrounding the right testicle (a). Citation, DOI, disclosures and article data. Compared to plain radiography, ultrasound, CT and MR provide higher sensitivity and specificity for the diagnosis of necrotizing fasciitis. All rights reserved. Maximum-intensity projection images reconstructed in the axial (A) and coronal (B) planes show bilateral arteriovenous malformations with corresponding feeding arteries (white arrows) and draining veins (black arrows). Even in osseous infection, CT and MRI can give better anatomic delineation of the extent of infection. Enter multiple addresses on separate lines or separate them with commas. 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. At the time the article was created The Radswiki had no recorded disclosures. 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 Radiologic Approach to Musculoskeletal Infections. During the injection you may feel flushed and get a metallic taste in your mouth. A 35-year-old male with necrotizing fasciitis of the right calf. sharing sensitive information, make sure youre on a federal 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. Hydration can decrease these risks. 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. Before 2021 Feb 1;94(1118):20200648. doi: 10.1259/bjr.20200648. 2001 Mar;39(2):277-303. doi: 10.1016/s0033-8389(05)70278-5. 2019;10(1):47. AJR Am J Roentgenol. Brothers TE, Tagge DU, Stutley JE, Conway WF, Del Schutte H, Byrne TK. Marked preseptal edema and discrete contrast enhancement in the area of the affected left upper eyelid. If the infection spreads to deeper tissues, soft-tissue abscess, infectious myositis, necrotising fasciitis, and osteomyelitis can all be detected with CT. MRI is sensitive for distinguishing cellulitis alone from necrotising fasciitis and infectious myositis and for showing subcutaneous fluid collections and abscesses. Unauthorized use of these marks is strictly prohibited. If youre a nurse practitioner who struggles with the same question, check out the following guide to contrast and CT scans. Radiology. The location and extent of the inflammatory process was accurately demonstrated with axial CT scans in all cases. The .gov means its official. Water-soluble, iodine-based contrast agents can also be given orally. At the time the article was last revised David Carroll had Fundic gland polyps: Should my patient stop taking PPIs? 4. 2022 Jul 10;11(14):3998. doi: 10.3390/jcm11143998. 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. Kirchgesner T, Tamigneaux C, Acid S et al. Necrotizing fasciitis: early sonographic diagnosis. Search dates: November 2009 and April 27, 2010. 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. Since the epidermis is not involved, cellulitis is not transmitted by person-to-person contact. Alaia E, Chhabra A, Simpfendorfer C et al. sonographic hallmarks of cellulitis include abnormal echogenicity and increased thickness of the dermis with indistinct "haziness" and increased echogenicity of the subcutaneous tissue, it is often helpful to compare the area in question to the (presumably normal)contralateral side, progressive accumulation of edema in the subcutaneous tissue appears as branching, anechoic striations which impart a lobulated ("cobble-stone" appearance), presence of thickened and abnormally echogenic overlying skin will favor cellulitis over edema, linear anechoic bands of fluid deep to the subcutaneous layer favor lymphedema, ultrasound is more sensitive than MRI for the detection of a retained foreign body as the causative agent, especially if small and wooden 4,5. Swartz M. Clinical Practice. Barium suspensions are not nephrotoxic and can be used safely in patients with renal failure. Skin findings, pain out of proportion, and signs of systemic shock should alert the clinician to the possibility of necrotizing fasciitis. Careers. A baseline serum creatinine level should be obtained up to one month before administration of intravenous contrast agents in patients with suspected renal insufficiency. There are several contrast agents that may be used in performing CT scans. 1Department of Radiology, Massachusetts General Hospital, Boston, MA, USA. 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. Inflammatory cellulitis is frequently confused with infectious cellulitis. MRI Nomenclature for Musculoskeletal Infection. eCollection 2022. In a 79-year-old patient with chronic thromboembolic pulmonary hypertension, CT angiography of the pulmonary artery (A) shows weblike (red arrow) and partially calcified filling defects (yellow arrow), as well as diffuse mild mosaic attenuation of lung parenchyma (B). Federal government websites often end in .gov or .mil. 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. Created for people with ongoing healthcare needs but benefits everyone. Reference article, Radiopaedia.org (Accessed on 01 May 2023) https://doi.org/10.53347/rID-15554. Working in the emergency department as a nurse practitioner, I order CT scans in my evaluation of patients every day. Contrast enhancement is also used to evaluate superior vena cava syndrome. Disease processes that involve calcifications may benefit from noncontrast-enhanced images because contrast may mask the appearance of calcifications. Cross-sectional imaging findings include asymmetric thickening of fascia, soft tissue air, blurring of fascial planes, inflammatory fat stranding, reactive lymphadenopathy, and nonenhancement of muscular fascia. This site needs JavaScript to work properly. A neck mass or adenopathy also may be investigated, particularly when it results in airway or vascular compromise. Large volume of gas seen within the scrotum wall and scrotum sac on the scout image (curved black arrow), consistent with Fourniers gangrene. Bethesda, MD 20894, Web Policies The specific agent and route of administration are based on clinical indications and patient factors. Version 10.1.2015, Intravenous contrast material exposure is not an independent risk factor for dialysis or mortality. If the infection spreads to deeper tissues, complications can occur, such as soft-tissue abscess,necrotising fasciitis,infectious myositis, and/or osteomyelitis. Muscular fascia lies deep to the subcutaneous layer. The site is secure. Possible reactions are listed in Table 1.7 If a patient has had a previous minor reaction to an IV iodinated contrast agent, precontrast administration of oral or IV corticosteroids and diphenhydramine (Benadryl) may decrease their risk (Table 27 ). High-resolution CT, which is used to evaluate diffuse lung disease, does not use IV contrast.17 Noncontrast imaging of the abdomen is routinely done to screen for renal stones in patients with flank pain.18 Common clinical scenarios in which noncontrast-enhanced CT is appropriate are summarized in Table 4,19 and common clinical scenarios in which contrast enhancement is recommended are summarized in Table 5.19 Indications for selection of imaging studies for specific clinical scenarios can be searched using the American College of Radiology Appropriateness Criteria at http://www.acr.org/ac.19. 2019;10(1):47. N Engl J Med. Your email address will not be published. Risk factors include chronic kidney disease, diabetes mellitus, heart failure, older age, anemia, left ventricular systolic dysfunction, and contrast volume. Weaver JS, Omar IM, Mar WA, Klauser AS, Winegar BA, Mlady GW, McCurdy WE, Taljanovic MS. Pol J Radiol. 2007 Nov-Dec;27(6):1723-36. doi: 10.1148/rg.276075033. Abstract. The decision to order contrast-enhanced CT is based on the clinical question being asked. 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. A 47-year-old male with necrotizing fasciitis of the left thigh. Required fields are marked *. Occasionally sepsis may result. Check for errors and try again. In cases of suspected arteriovenous malformation, a protocol similar to that used for suspected pulmonary embolus is used (Figure 3), although in some instances, the imaging features of arteriovenous malformation may be detectable without IV contrast. 2017 Jun;31(2):299-324. doi: 10.1016/j.idc.2017.01.004. Crit Rev Diagn Imaging. Other contrast media, such as those used for magnetic resonance imaging or barium enemas, do not contain iodine. Necrotizing fasciitis: CT characteristics. Fasciae of the Musculoskeletal System: MRI Findings in Trauma, Infection and Neoplastic Diseases. A 39-year-old male with necrotizing fasciitis of the right ankle. 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. 2004;350(9):904-12. CT may also be ordered for cross-sectional images of the spine with contrast in the thecal sac. At our institution, to assess dynamic airway narrowing, we use a dedicated airway protocol, including inspiratory and expiratory phases and multi-planar reformatted images. 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. Biomed Res Int. The https:// ensures that you are connecting to the Many types of contrast agents can be used in computed tomography: oral, intravenous, rectal, and intrathecal. E-mail: Received 2018 Jan 20; Revised 2018 Mar 2; Accepted 2018 Mar 8. 2004;350(9):904-12. Contrast agents are used to differentiate between organs and improve lesion detection and characterization. Intrathecal iodinated contrast is given during myelography to evaluate spinal or basal cisternal disease and cerebrospinal fluid leaks.11 Plain radiography of the spine is then obtained under fluoroscopic guidance. Yen ZS, Wang HP, Ma HM, Chen SC, Chen WJ. If you have questions about ordering your patient's CT, we encourage you to speak with a radiologist about the study and the need for contrast.
