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. Your email address will not be published. Author disclosure: No relevant financial affiliations. Below is an overview of the following CTA studies and their indications: Regardless of the pathology youre looking for, contrast isnt right for everyone. 1998;170(3):615-20. Although classically a clinical diagnosis, imaging is a powerful adjunct to facilitate early diagnosis in equivocal cases. Kim KT, Kim YJ, Won Lee J, Kim YJ, Park SW, Lim MK, et al.. Can necrotizing infectious fasciitis be differentiated from nonnecrotizing infectious fasciitis with MR imaging? AJR Am J Roentgenol. It is injected through an intravenous line during the examination. In B, the native left lung is small, with evidence of bronchiectasis, bronchiolectasis, and areas of honeycombing (black arrow). The American College of Radiology Appropriateness Criteria is a useful online resource. When does chest CT require contrast enhancement? Barium suspension from fluoroscopy or CT will not produce an artifact on abdominal magnetic resonance imaging. Diagnosis of necrotizing soft tissue infections by computed tomography. Unenhanced CT is also used in patients with spine and extremity trauma. 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 edema, areas of necrotizing cellulitis do not enhance, degree of enhancement depends on the post contrast delay. 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. The parapharyngeal space was the most commonly involved space. 70470 Metastases/Known cancer HIV Intracranial infection Note: CT can be used if there are contraindications for MRI. Assessment of interstitial lung disease does not require use of IV contrast; rather, a tailored protocol with thinner slices and non-contiguous expiratory images can be used to evaluate for air-trapping and dynamic airway compromise (Figure 4). In cases where the plain film and nuclear medicine bone scan findings are complicated due to previous surgery, trauma, or underlying illness, the anatomic resolution and soft tissue contrast provided by MRI and CT are often necessary to determine if underlying infection exists. PDF CT SCANS AND IV CONTRAST UTILIZATION - United Radiology Group, Chartered Signs of cellulitis are easy to appreciate on CT and MRI and include thickening of the fat, best appreciated on the preseptal space, fat infiltration, and contrast enhancement. 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. Check for errors and try again. Other CT findings include increase soft-tissue attenuation, subcutaneous edema and inflammatory fat stranding, which can also be seen in cellulitis.2,2123 In a study by Wysoki et al. 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. 2021 Feb 1;94(1118):20200648. doi: 10.1259/bjr.20200648. It results in pain, erythema, oedema, and warmth. [18F]Fluoride Positron-Emission Tomography (PET) and [18F]FDG PET for Assessment of Osteomyelitis of the Jaw in Comparison to Computed Tomography (CT) and Magnetic Resonance Imaging (MRI): A Prospective PET/CT and PET/MRI Pilot Study. Would you like email updates of new search results? Special consideration should be given to geriatric patients, in whom cellulitis of the lower extremities is more likely to develop into thrombophlebitis. 5. When I was newer to my role, I had a lot of questions about diagnostic imaging, when it was indicated, and what test to order. Special consideration should be given to geriatric patients, in whom cellulitis of the lower extremities is more likely to develop into thrombophlebitis. Diagnosing Pediatric Orbital Cellulitis: CT or rMRI? Hydration can decrease these risks. PDF CT Exams Contrast vs Non-Contrast Guide - Oregon Imaging Although a very uncommon soft-tissue infection, it has significant mortality up to 7080% and constitutes a life-threatening surgical emergency.1, 2 The most important predictor of mortality is a delay in diagnosis, thus it is essential to make a prompt diagnosis.2 Clinically, the findings of necrotizing fasciitis can overlap with other soft-tissue infections including cellulitis, abscess or even compartment syndrome, but pain out of proportion to the degree of skin involvement and signs of systemic shock should alert the clinician to the possibility of necrotizing fasciitis.46 Other red flag clinical findings are listed in Table 1. BMJ. If a diagnosis of orbital cellulitis is made, the patient needs to be immediately assessed monitored for signs of compartment syndrome and optic neuropathy which would warrant an . Alaia E, Chhabra A, Simpfendorfer C et al. Iodinated contrast crosses the human placenta. 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). In uncomplicated cellulitis, CT demonstrates skin thickening, septation of the subcutaneous fat, and thickening of the underlying superficial fascia. Even in osseous infection, CT and MRI can give better anatomic delineation of the extent of infection. 2001 Oct;42(4-5):259-305. During the injection you may feel flushed and get a metallic taste in your mouth. At the time the article was created The Radswiki had no recorded disclosures. Miller TT, Randolph DA, Staron RB, Feldman F, Cushin S. Fat-suppressed MRI of musculoskeletal infection: fast T2-weighted techniques versus gadolinium-enhanced T1-weighted images, Necrotizing fasciitis: unreliable MRI findings in the preoperative diagnosis, Differentiation of necrotizing fasciitis and cellulitis using MR imaging. Imaging of Musculoskeletal Soft Tissue Infections. Epidemiology Risk factors trauma foreign bodies CT head without IV contrast Usually Not Appropriate . 1 0 obj 2019;10(1):47. 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. Abdominal and/or pelvic pain-acute or chronic 2. CT LUMBAR SPINE W CONTRAST (IMG214) 72126 72129 72132 EXTREMITIES Fracture, Abnormal pathology. 3. Swartz M. Clinical Practice. Unable to process the form. Biomed Res Int. 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. Above this, there is a narrow, relatively hyperechoic epidermal-dermal layer. official website and that any information you provide is encrypted Radiologic Approach to Musculoskeletal Infections. 2021;50(12):2319-47. The overall PPV for the prediction of deep neck abscess with contrast-enhanced CT was 79.6%. Bethesda, MD 20894, Web Policies Alaia E, Chhabra A, Simpfendorfer C et al. 1998;170(3):615-20. Wall DB, Klein SR, Black S, de Virgilio C. A simple model to help distinguish necrotizing fasciitis from nonnecrotizing soft tissue infection. Specific imaging features exist that help identify the numerous forms of infection in the bones and soft tissues, and CT is invaluable for detecting deep complications of cellulitis and pinpointing the anatomic compartment that is involved by an infection. Sinus radiographs, which were also obtained, were not helpful in diagnosis or management. In certain situations, however, a contrast medium is essential. Risk factors include chronic kidney disease, diabetes mellitus, heart failure, older age, anemia, left ventricular systolic dysfunction, and contrast volume. The most common are baruim and iodine based. Moran CORE | Preseptal vs Orbital Cellulitis - University of Utah Disclaimer. endobj Cellulitis (rare plural: cellulitides) is an acute infection of the dermis and subcutaneous tissues without deep fascial or muscular involvement. Magnetic resonance imaging differentiates between necrotizing and non-necrotizing fasciitis of the lower extremity. Necrotizing fasciitis: early sonographic diagnosis. Cellulitis | Radiology Reference Article | Radiopaedia.org 2. The PPV was 91.3% when more than one deep neck space was involved but only 50.0% in patients with isolated retropharyngeal abscesses. The https:// ensures that you are connecting to the 2 0 obj Musculoskeletal Infection: Role of CT in the Emergency Department Peri-orbital cellulitis is of concern in children because it may be secondary to occult underlying bacterial sinusitis or, rarely, due . A 39-year-old-male with necrotizing fasciitis of the right thigh. High Resolution Chest CT This is a specialized CT of the lungs performed without IV contrast. Clinical findings suggestive of necrotizing fasciitis vs cellulitis.7, There have been association with intravenous drug use as well as chronic conditions including diabetes mellitus, immunosuppression, obesity, and peripheral vascular disease.3, 8 A history of recent surgery (within the past 90 days) at the affected site has been shown to be a strong predictor for necrotizing fasciitis.7, Infection typically begins in the superficial fascial planes, then rapidly progress into the deep fascial layers, which causes necrosis secondary to microvascular occlusion.1 The rate of spread of infection is directly proportional to the thickness of the subcutaneous layers, with fastest spread seen in the lower extremities due to the lack of fibrous boundaries between subcutaneous tissue and fascia.2, 9, Necrotizing fasciitis is a clinical diagnosis since imaging findings can be nonspecific or unremarkable early in the course of the disease.1 The majority of cases are initially misdiagnosed, causing delay in diagnosis.10 Imaging appearances of necrotizing fasciitis can also overlap with other conditions, including nonnecrotizing fasciitis, dermatomyositis, graft vs host disease, or ischemic myonecrosis.1 The main utility of imaging is to determine the extent of the soft-tissue infection as well as to guide surgical planning.1, 8 If the patient is presenting with shock, imaging should not delay the initiation of treatment.1 Definitive diagnosis is based on surgical exploration and biopsy and aggressive surgical fasciotomy of necrotic tissue is required to prevent the spread of infection.7, Early findings of necrotizing fasciitis on radiography can appear similar to cellulitis including soft-tissue opacity and thickening.1113 The classical findings of dissecting gas along fascial planes in the absence of trauma is a specific sign, but is only seen in 24.855.0% of patients, and may not be seen until late in the disease (Figures 1 and 2).1, 10,12 Necrotizing fasciitis commonly affects the lower extremities, with involvement of the perineum or scrotum, classically known as Fourniers gangrene (Figure 3).3, 14,15 Soft-tissue gas is typically caused by gas-forming anaerobic infections, although this may not be present in diabetic patients.16 As such, the absence of soft-tissue emphysema does not exclude a diagnosis of necrotizing fasciitis.1. Address correspondence to: Dr David K Tso. Postoperative sternal wound infections are not uncommon and range from cellulitis to frank osteomyelitis. Uncomplicated cellulitis is usually treated conservatively with antibiotics and locally supportive measures. Clinical presentations include skin erythema without a well-defined border, increased skin temperature, swelling of the affected area, and regional lymphadenopathy and lymphangitis. Cellulitis (rare plural: cellulitides) is an acute infection of the dermis and subcutaneous tissues without deep fascial or muscular involvement. official website and that any information you provide is encrypted eCollection 2022. Within three days of starting an antibiotic, let your health care provider know whether the infection is responding to treatment. All rights reserved. government site. The information provided is for educational purposes only. 1. Preparation: Please have only a clear liquid diet for 4 hours prior to exam. The site is secure. 2015;2015:587857. doi: 10.1155/2015/587857. 2007 Nov-Dec;27(6):1723-36. doi: 10.1148/rg.276075033. 2004;350(9):904-12. 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 ). Prior to contrast administration, patients should be asked about previous allergy to CT contrast. <>/Metadata 2 0 R/ViewerPreferences 6 0 R>> Spinnato P, Patel DB, Di Carlo M, Bartoloni A, Cevolani L, Matcuk GR, Cromb A. Microorganisms. Magnetic resonance imaging of musculoskeletal infections. Copyright 2023 American Academy of Family Physicians. 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. Patients with history of anaphylactic reaction should not receive contrast. Inflammatory cellulitis is frequently confused with infectious cellulitis. Clinical presentations include skin erythema without a well-defined border, increased skin temperature, swelling of the affected area, and regional lymphadenopathy and lymphangitis. Accessibility CT is used to accurately differentiate between superficial cellulitis and deep cellulitis. 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. 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 Even in osseous infection, CT and MRI can give better anatomic delineation of the extent of infection. Zacharias N, Velmahos GC, Salama A, Alam HB, de Moya M, King DR, et al.. N Engl J Med. During the injection you may feel flushed and get a metallic taste in your mouth. Occasionally sepsis may result. 4. When to Order Contrast-Enhanced CT | AAFP Uncomplicated cellulitis is usually treated conservatively with antibiotics and locally supportive measures. Necrotizing fasciitis of the lower extremity: imaging pearls and x]6}W&VqeYjc=ZZgvmH]"2EV"KL D~x9n_O=~on~{,Je|Sn*nqis7^xgi| RUSpEzs_^c?nRW%74|q)PB#g3F|k9/tp8.r#5zv+t3/z,$f S$Uz`X, Suspected Osteomyelitis, Septic Arthritis, or Soft Tissue Infection (Excluding Spine and Diabetic Foot). This site needs JavaScript to work properly. Peri-orbital and orbital cellulitis - BMJ Best Practice Cellulitis(rare plural: cellulitides) is an acute infection of the dermis and subcutaneous tissues without deep fascial or muscular involvement. Symptoms typically disappear a few . Skeletal Radiol. HHS Vulnerability Disclosure, Help However, IV radiologic contrast may cause transient alteration in renal function, which could impair metformin clearance, leading to a higher risk of metabolic acidosis. A 35-year-old male with necrotizing fasciitis of the right calf. Although many radiology departments screen for shellfish allergy, there is no cross-reactivity between shellfish and iodinated contrast. Contrast-enhanced CT demonstrates crescentic subfascial fluid (arrow) with fluid also seen superficial to the fascia (arrow head) and between muscle planes (a).

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