Necrotizing fasciitis: early sonographic diagnosis. Muscular fascia lies deep to the subcutaneous layer. <>/ExtGState<>/ProcSet[/PDF/Text/ImageB/ImageC/ImageI]>>/MediaBox[0 0 612 792]/Contents 30 0 R/Group<>/Tabs/S/StructParents 0>> 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). References. There are several contrast agents that may be used in performing CT scans. 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. Jamal K, Mandel L, Jamal L, Gilani S. 'Out of hours' adult CT head interpretation by senior emergency department staff following an intensive teaching session: a prospective blinded pilot study of 405 patients. Chaudhry AA, Baker KS, Gould ES, Gupta R. Necrotizing fasciitis and its mimics: what radiologists need to know, Musculoskeletal infection: role of CT in the emergency department. There is no direct interaction between metformin and IV radiologic contrast agents. . The concentration of barium determines whether it enhances the diagnosis or causes an artifact and obscures pathology. Cross-sectional schematic diagram through the right thigh demonstrating the various findings of necrotizing fasciitis. 4. While the plain film and nuclear medicine bone scan are still the traditional imaging modalities used in the evaluation of musculoskeletal infection, the cross-sectional imaging modalities, computed tomography (CT) and magnetic resonance imaging (MRI), have become critical in the delineation of many types of musculoskeletal infection. Although classically a clinical diagnosis, imaging is a powerful adjunct to facilitate early diagnosis in equivocal cases. Preparation: Please have only a clear liquid diet for 4 hours prior to exam. Radiographics. Extensive streaky soft-tissue gas is seen extending along the fascial planes of the right thigh on radiograph. sharing sensitive information, make sure youre on a federal MRI Nomenclature for Musculoskeletal Infection. All rights reserved. Your email address will not be published. A 64-year-old male with Fourniers gangrene with perforated diverticulitis. My answer is based on the current radiologic practices and terminology employed in the U.S. 1. Finally, imaging of the abdomen and pelvis to assess for renal stones also does not require CT contrast. Iodinated contrast crosses the human placenta. Different imaging modalities require different concentrations of contrast for optimal detection of pathology. Contrast-enhanced CT demonstrates crescentic subfascial fluid (arrow) with fluid also seen superficial to the fascia (arrow head) and between muscle planes (a). 2020;368:m710. AJR Am J Roentgenol. National Library of Medicine 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. This question is for testing whether or not you are a human visitor and to prevent automated spam submissions. Zacharias N, Velmahos GC, Salama A, Alam HB, de Moya M, King DR, et al.. The parapharyngeal space was the most commonly involved space. Hayeri MR, Ziai P, Shehata ML, Teytelboym OM, Huang BK. 2009;39(10):957-71. Axial CT with contrast enhancement obtained subsequently (B and C) shows that this abnormality corresponds to right hilar lymphadenopathy partially encasing the right pulmonary artery (arrows). Swartz M. Clinical Practice. All Rights Reserved. Necrotizing fasciitis: contribution and limitations of diagnostic imaging. Imaging of Musculoskeletal Soft Tissue Infections. Many types of contrast agents can be used in computed tomography: oral, intravenous, rectal, and intrathecal. 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 would delay a diagnosis in the trauma setting. Soft-tissue gas is a specific finding on all modalities, but is not present in all patients with necrotizing fasciitis. Case 1: orbital and periorbital cellulitis, see full revision history and disclosures. 6. Symptoms typically disappear a few . Fugitt JB, Puckett ML, Quigley MM, Kerr SM. 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. 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. endobj Necrotizing fasciitis: CT characteristics. Occasionally sepsis may result. Imaging of Musculoskeletal Soft-Tissue Infections in Clinical Practice: A Comprehensive Updated Review. Marked preseptal edema and discrete contrast enhancement in the area of the affected left upper eyelid. Kidney/ureteral stones With IV contrast 1. 2001 Mar;39(2):277-303. doi: 10.1016/s0033-8389(05)70278-5. Citation, DOI, disclosures and article data. When is contrast needed for abdominal and pelvic CT? Ultrasound is helpful to rule out deep venous thrombosis, assess for possible foreign bodies, and guide potential diagnostic fluid aspiration.8, 13 Sensitivity of ultrasound for the diagnosis of necrotizing fasciitis is 88.2%, with a specificity of 93.3%.20, CT is the primary imaging modality in the work-up of necrotizing fasciitis given its wide availability and high spatial resolution compared to radiography or ultrasound.3 Soft-tissue gas is a pertinent CT finding, but absence of it should not exclude the diagnosis of necrotizing fasciitis if clinically suspected.1, 2,11,17 Gas within fluid collections along subfascial planes is the hallmark of necrotizing fasciitis (Figures 5 and 6).11, 21 The lack of soft-tissue gas on CT may be due to early disease, aerobic infections, or if the patient is diabetic.1, 16 The sensitivity of CT in diagnosing necrotizing fasciitis is 80%, but it lacks specificity as findings can also be seen in nonnecrotizing fasciitis.21, 22 Thickening and nonenhancement of the fascia on contrast-enhanced CT may be helpful to distinguish from nonnecrotizing fasciitis.2 Subfascial and intermuscular fluid accumulation can also be seen on CT, and may represent early findings of necrotizing fasciitis (Figure 7).21. The overall PPV for the prediction of deep neck abscess with contrast-enhanced CT was 79.6%. NOTE: We only request your email address so that the person you are recommending the page to knows that you wanted them to see it, and that it is not junk mail. government site. Normally the subcutaneous tissue is hypoechoic with few hyperechoic strands (representing connective tissue). Abstract. Weaver JS, Omar IM, Mar WA, Klauser AS, Winegar BA, Mlady GW, McCurdy WE, Taljanovic MS. Pol J Radiol. 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. Dr. Amy Levine answered. CT LUMBAR SPINE W CONTRAST (IMG214) 72126 72129 72132 EXTREMITIES Fracture, Abnormal pathology. Infection, inflammation, and edema of the lung parenchyma are usually well depicted on CT without contrast enhancement. A CT can help determine the underlying cause of orbital cellulitis. Since the epidermis is not involved, cellulitis is not transmitted by person-to-person contact. Bakleh M, Wold LE, Mandrekar JN, Harmsen WS, Dimashkieh HH, Baddour LM. Prior to contrast administration, patients should be asked about previous allergy to CT contrast. 7 0 obj All Rights Reserved. One of these questions that came up frequently related to CT scans was Do I need contrast?. A 39-year-old-male with necrotizing fasciitis of the right thigh. 1. 2 0 obj % At the time the article was last revised David Carroll had Abdominal and/or pelvic pain-acute or chronic 2. Shortness of breath Abdomen andPelvis Without IV contrast 1. Sinus radiographs, which were also obtained, were not helpful in diagnosis or management. IV contrast may be used to visualize vasculature as well as the internal organs of the abdomen and pelvis. Many practices have their own protocols for IV dye administration in patients using metformin so nurse practitioners must familiarize themselves with these policies. Contrast enhancement is also used to evaluate superior vena cava syndrome. <>stream A CT scan shows detailed images of any part of the body, including the bones, muscles, fat, organs, and blood vessels. CT head without IV contrast Usually Not Appropriate . 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. Contrast materials are generally safe; however, as with any pharmaceutical, there is the potential for adverse reactions. In pleural effusion, CT assessment for the presence, location, and extent of the effusion does not require contrast. and transmitted securely. Mitchell C, Dolan N, Drsteler K. Management of Dependent Use of Illicit Opioids. 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. Sagittal CT reformation demonstrates linear fluid collection (arrow) deep to the rectus femoris muscle (b). Some centers use oral contrast to evaluate for appendicitis; some do not use bowel contrast,3 and others use rectal contrast to avoid the delay associated with oral administration.4, Iodine-based intravenous (IV) contrast agents are used for opacification of vascular structures and solid abdominal and pelvic organs. As with barium agents, they must be diluted for CT compared with the concentrations used in fluoroscopy. 2nd ed. myriad of non-infective erythematous rashes, Please Note: You can also scroll through stacks with your mouse wheel or the keyboard arrow keys. Crit Rev Diagn Imaging. 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. This site needs JavaScript to work properly. In a patient with colon cancer undergoing a workup for metastases, axial CT without contrast (A) shows prominence of the right hilar region (arrow). Mediastinitis may likewise be iatrogenic or may spread from the oropharynx. Negative studies or nonspecific findings in the context of high clinical suspicion for necrotizing fasciitis, should be treated promptly as this is a clinical diagnosis. 2009;39(10):957-71. Horton L, Jacobson J, Powell A, Fessell D, Hayes C. Sonography and Radiography of Soft-Tissue Foreign Bodies. The major families of contrast agents are ionic and nonionic. BMJ. ADVERTISEMENT: Radiopaedia is free thanks to our supporters and advertisers. Uncomplicated cellulitis is usually treated conservatively with antibiotics and locally supportive measures. Patients with history of anaphylactic reaction should not receive contrast. Alaia E, Chhabra A, Simpfendorfer C et al. Barium suspensions are not nephrotoxic and can be used safely in patients with renal failure. 3 0 obj E-mail: Received 2018 Jan 20; Revised 2018 Mar 2; Accepted 2018 Mar 8. Compared to plain radiography, ultrasound, CT and MR provide higher sensitivity and specificity for the diagnosis of necrotizing fasciitis. 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. Fascial thickening and involvement of multiple compartments is a sensitive finding on MRI. Cellulitis can affect any region of the body, and commonly affects a lower limb. Metformin should be held for 48 hours after the administration of IV contrast, and resumed only after serum creatinine returns to baseline levels, according to the U.S. Food and Drug Administration. Correlation of histopathologic findings with clinical outcome in necrotizing fasciitis. Scout film (a) and contrast-enhanced CT (b) shows intramuscular pockets of gas (arrows) in the left lateral thigh. 2022 Jul 10;11(14):3998. doi: 10.3390/jcm11143998. 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. 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. Radiology. 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 . 7. It is injected through an intravenous line during the examination. Speak with a Radiologist: 541-284-4016 In uncomplicated cellulitis, CT demonstrates skin thickening, septation of the subcutaneous fat, and thickening of the underlying superficial fascia. Necrotizing fasciitis is a rapidly spreading soft tissue infection involving the deep fascial layers, which can cause secondary necrosis leading to significant morbidity and mortality.13 It most commonly affects the lower extremities accounting for approximately 50% of cases, and can affect different body parts including the perineum (as in Fourniers gangrene), and submandibular region (as in Ludwig angina). Skeletal Radiol. 1998;170(3):615-20. 2022 Nov 25;10(12):2329. doi: 10.3390/microorganisms10122329. Orbital cellulitis. 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. Above this, there is a narrow, relatively hyperechoic epidermal-dermal layer. 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. MR Imaging in Acute Infectious Cellulitis. Fundic gland polyps: Should my patient stop taking PPIs? Created for people with ongoing healthcare needs but benefits everyone. 1994;192(2):493-6. AJR Am J Roentgenol. %PDF-1.7 Although many radiology departments screen for shellfish allergy, there is no cross-reactivity between shellfish and iodinated contrast. CT without contrast in a patient with a history of interstitial lung disease and right lung trans-plant shows the patent but partially narrowed anastomotic site of the right bronchus (A) (red arrow). It results in pain, erythema, oedema, and warmth. Thank you for your interest in spreading the word on Cleveland Clinic Journal of Medicine. 2. 9. Epub 2015 Apr 29. Required fields are marked *. 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. In uncomplicated cellulitis, CT demonstrates skin thickening, septation of the subcutaneous fat, and thickening of the underlying superficial fascia. 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. Nurse practitioners must be familiar with the contraindications for CT contrast administration. During the injection you may feel flushed and get a metallic taste in your mouth. 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. HHS Vulnerability Disclosure, Help 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. It is usually due to underlying bacterial sinusitis. 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. Even in osseous infection, CT and MRI can give better anatomic delineation of the extent of infection. no financial relationships to ineligible companies to disclose. 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. Compared to plain radiography, ultrasound, CT and MR provide higher sensitivity and specificity for the diagnosis of necrotizing fasciitis. A 35-year-old male with necrotizing fasciitis of the right calf. Since the epidermis is not involved, cellulitis is not transmitted by person-to-person contact. Before Clipboard, Search History, and several other advanced features are temporarily unavailable. Contrast is not used in patients with head, extremity or spine trauma. 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 No mutagenic or teratogenic effects have been shown with nonionic, low-osmolality contrast in animal studies. 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. Large volume of gas seen within the scrotum wall and scrotum sac on the scout image (curved black arrow), consistent with Fourniers gangrene. Reinert CP, Pfannenberg C, Dittmann H, Gckel B, la Fougre C, Nikolaou K, Hoefert S. J Clin Med. In patients with normal renal function, repeat measurement of serum creatinine is not recommended after outpatient administration of IV contrast agents.7. Emergency Medicine: Clinical Essentials. Barium suspension from fluoroscopy or CT will not produce an artifact on abdominal magnetic resonance imaging. 7. However, contrast enhancement is used to evaluate suspected or known exudative effusions and empyema.6 It also aids the evaluation of metastatic or primary malignancy of the pleura, particularly in cases of occult disease, as enhancement and thickening of the pleura are of diagnostic interest. Bethesda, MD 20894, Web Policies Within three days of starting an antibiotic, let your health care provider know whether the infection is responding to treatment. Hydration can decrease these risks. Even in osseous infection, CT and MRI can give better anatomic delineation of the extent of infection. The need for enhancement with intravenous (IV) contrast depends on the specific clinical indication (Table 1). The soft-tissue air deep to the fascia is seen as multiple echogenic foci (arrows) on ultrasound study (b). In B, the native left lung is small, with evidence of bronchiectasis, bronchiolectasis, and areas of honeycombing (black arrow). a central core consisting of necrotic inflammatory cells and local tissue peripheral halo of viable neutrophils surrounded by a 'capsule' with dilated blood vessels and proliferation of fibroblasts Terminology An abscesses is akin to an empyema, as both are defined inflammatory collections. Rectal contrast can be used in patients with a suspected penetrating colonic injury.2 Rectal contrast does not always reach the cecum, so the small bowel and appendix can remain unopacified. Since the epidermis is not involved, cellulitis is not transmitted by person-to-person contact. Initial radiographs show soft tissue gas (without puncture wound) or are normal with high clinical suspicion of necrotizing fasciitis. A ct urogram uses IV contrast (dye) to better evaluate the renal pelvis and ureter (the "tube" connecting your kidneys t. Read More. Enter multiple addresses on separate lines or separate them with commas. Premedication with antihistamines and corticosteroids is recommended in patients with a history of mild to moderate reactions to intravenous contrast agents. Insights Imaging. A 57-year-old diabetic male with pneumoscrotum. These reactions are relatively rare and are usually mild but occasionally can be severe.9 Anaphylactoid reactions have an unclear etiology but mimic allergic reactions, and they are more likely to occur in patients with a previous reaction to contrast and in patients with asthma or cardiovascular or renal disease. Unable to process the form. Yen ZS, Wang HP, Ma HM, Chen SC, Chen WJ. In cases of question, Computed tomography (CT) with and without contrast of the orbits and sinuses should be ordered to look for evidence of post-septal involvement. Clear communication between the physician and radiologist is essential for obtaining the most appropriate study at the lowest cost and risk to the patient. <> 1998;170(3):615-20. 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. Below is an overview of the following CTA studies and their indications: Regardless of the pathology youre looking for, contrast isnt right for everyone. Imaging of Musculoskeletal Soft Tissue Infections. 2019;10(1):47. MR Imaging in Acute Infectious Cellulitis. There is subcutaneous emphysema (arrows) overlying the right ankle with plate and screw fixation seen (a). Answer (1 of 4): You asked: Are CT scans without contrast always done before CT scans with contrast? Since the epidermis is not involved, cellulitis is not transmitted by person-to-person contact. {"url":"/signup-modal-props.json?lang=us"}, Radswiki T, Carroll D, Knipe H, et al. Above this, there is a narrow, relatively hyperechoic epidermal-dermal layer. <>/Metadata 2 0 R/ViewerPreferences 6 0 R>> : Elsevier Health Sciences, 2013;633-644. Gk MC, Turhan Y, Demirolu M, Kl B, Akku M, zkan K. Radiological assessment in necrotizing fasciitis. With respect to employing CT as an imaging modality, first one should be aware of the different ty. CT area of interest without IV contrast Usually Appropriate Varies Variant 7: Suspected soft tissue infection. Paz Maya S, Dualde Beltrn D, Lemercier P, Leiva-Salinas C. Necrotizing fasciitis: an urgent diagnosis. Check for errors and try again. Family physicians often must determine the most appropriate diagnostic tests to order for their patients. manolo villaverde death, disadvantages of compassionate leadership,