8. PMC However, contrast may be helpful if there are concerns about complications such as chest wall involvement, where contrast enhancement may help further delineate the extent of complications. Bethesda, MD 20894, Web Policies <>stream Contrast agents are used to differentiate between organs and improve lesion detection and characterization. 9. What are the treatment options for myasthenia gravis if first-line agents fail? [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. MRI Nomenclature for Musculoskeletal Infection. Copyright 2023 American Academy of Family Physicians. Preparation: Please have only a clear liquid diet for 4 hours prior to exam. 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. In later stages, nonenhancement of the fascia may be seen due to necrosis, which can be helpful to differentiate from nonnecrotizing fasciitis.3, 28,29, Although more apparent on CT, gas in the soft tissues is represented by punctate or curvilinear T1 and T2 low signal with corresponding blooming artifact on gradient echo sequences.1, 18,25,30 Although a highly specific finding, the absence of soft-tissue gas does not exclude the diagnosis of necrotizing fasciitis.3, 11. If youre ever stuck when it comes to the correct diagnostic imaging method for your patient, pick up the phone and call the radiologist or imaging facility with whom you work. Order "HAND" if entire wrist and hand. 5. Careers. doi: 10.5114/pjr.2022.113825. 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. Cellulitis. Uncomplicated cellulitis is usually treated conservatively with antibiotics and locally supportive measures. Patients with peripheral vascular disease or diabetes mellitusare particularly susceptible to cellulitis since minor injuries to the skin or cracked skin in the feet or toes can serve as a point of entry for infection. A paranasal sinus pathology is . 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 ). Barium suspensions are not nephrotoxic and can be used safely in patients with renal failure. No circumscribed collection, or signs of bulbar or intraconal involvement (note the preservation of the normal intraorbital fat density). Copyright 2023 The Cleveland Clinic Foundation. Even in osseous infection, CT and MRI can give better anatomic delineation of the extent of infection. Before 2. Mitchell C, Dolan N, Drsteler K. Management of Dependent Use of Illicit Opioids. The .gov means its official. Yes neuro CTa HeaD Circle of Willis CTA Head with and without contrast Note: MRA Brain without contrast is preferred. 2021 Feb 1;94(1118):20200648. doi: 10.1259/bjr.20200648. 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. 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. Epub 2017 Mar 30. It results in pain, erythema, oedema, and warmth. Thirteen orbital computed tomographic (CT) scans were obtained in 12 patients with postseptal (orbital) cellulitis. CT head without IV contrast Usually Not Appropriate . 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. A history of anaphylactic reactions would preclude IV contrast except in extreme emergencies. Imaging of Musculoskeletal Soft Tissue Infections. Version 10.1.2015, Intravenous contrast material exposure is not an independent risk factor for dialysis or mortality. 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. Despite its limitations, radiographs can be more sensitive than physical exam for the detection of soft-tissue gas, with radiographic findings present before clinical crepitus is detected.17 Radiographs can also be helpful in identifying other causes of infection including the presence of a foreign body or underlying fracture.3, 13, The role of ultrasound is limited in the work-up of necrotizing fasciitis given that the lack of resolution of deeper structures.8 The presence of soft-tissue gas can be more apparent on ultrasound compared to radiographs.17, 18 Findings include an echogenic layer of gas above the deep fascia with posterior dirty acoustic shadowing (Figure 4).19 Other nonspecific findings include hyperechogenicity of the overlying fat, with cobblestone appearance indicating subcutaneous edema, but these findings can also be seen in cellulitis or anasarca.8, 19 Color Doppler evaluation may not reveal hypervascularity.8 Specific signs that are helpful to differentiate necrotizing fasciitis from cellulitis include irregularity of the fascia, abnormal fluid collection along fascial planes, and diffuse fascia thickening when compared to the contralateral unaffected side.8. Magnetic resonance imaging of musculoskeletal infections. Detailed protocols for premedication and management of contrast adverse reactions are beyond the scope of this review and the reader is advised to refer to dedicated manuals.10. 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. Necrotizing fasciitis: CT characteristics. Swartz M. Clinical Practice. A 45-year-old male with necrotizing fasciitis of the right thigh. Kirchgesner T, Tamigneaux C, Acid S et al. Diagnosis of necrotizing soft tissue infections by computed tomography. In particular, the evaluation of soft tissue infections, including cellulitus, myositis, fasciitis, abscess, and septic arthritis are often best evaluated by MRI or CT due to their excellent anatomic resolution and soft tissue contrast. References. Risk factors include chronic kidney disease, diabetes mellitus, heart failure, older age, anemia, left ventricular systolic dysfunction, and contrast volume. 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). Cellulitis (rare plural: cellulitides) is an acute infection of the dermis and subcutaneous tissues without deep fascial or muscular involvement. Diffuse thickening of the superficial fascia, which can be seen in the early phase of necrotizing fasciitis (c). The site is secure. Since the epidermis is not involved, cellulitis is not transmitted by person-to-person contact. 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. Clinical presentations include skin erythema without a well-defined border, increased skin temperature, swelling of the affected area, and regional lymphadenopathy and lymphangitis. 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. The PPV was 91.3% when more than one deep neck space was involved but only 50.0% in patients with isolated retropharyngeal abscesses. 6. 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. Cellulitis (rare plural: cellulitides) is an acute infection of the dermis and subcutaneous tissues without deep fascial or muscular involvement. Cellulitis treatment usually includes a prescription oral antibiotic. Shortness of breath Abdomen andPelvis Without IV contrast 1. In Vivo MicroCT Monitoring of Osteomyelitis in a Rat Model. and transmitted securely. 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. Alaia E, Chhabra A, Simpfendorfer C et al. An official website of the United States government. Inflammatory cellulitis is frequently confused with infectious cellulitis. It is injected through an intravenous line during the examination. Scout film (a) and contrast-enhanced CT (b) shows intramuscular pockets of gas (arrows) in the left lateral thigh. It results in pain, erythema, edema, and warmth. Epub 2015 Apr 29. 2001 Mar;39(2):277-303. doi: 10.1016/s0033-8389(05)70278-5. Malghem J, Lecouvet FE, Omoumi P, Maldague BE, Vande Berg BC. Clinical presentations include skin erythema without a well-defined border, increased skin temperature, swelling of the affected area, and regional lymphadenopathy and lymphangitis. Created for people with ongoing healthcare needs but benefits everyone. Finally, imaging of the abdomen and pelvis to assess for renal stones also does not require CT contrast. no financial relationships to ineligible companies to disclose. Iodinated contrast agents can cause reversible acute renal failure. <> BMJ. Interstitial lung disease 2. 70470 Metastases/Known cancer HIV Intracranial infection Note: CT can be used if there are contraindications for MRI. The .gov means its official. Your email address will not be published. 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. Diseases of the large airway, such as stenosis and thickening, and diseases of the small airways, such as bronchiolitis, typically do not require contrast enhancement. Water-soluble, iodine-based contrast agents can also be given orally. Marked preseptal edema and discrete contrast enhancement in the area of the affected left upper eyelid. However, if contrast must be administered within two months of iodine 131 treatment, consultation with an endocrinologist should be considered.7 Administration of iodinated contrast may provoke thyrotoxicosis, although this is rare.12, Approximately 90% of absorbed metformin is excreted by the kidneys within 24 hours. IV contrast may be used to visualize vasculature as well as the internal organs of the abdomen and pelvis. IV dye may cause a temporary alteration in kidney function. Cross-sectional schematic diagram through the right thigh demonstrating the various findings of necrotizing fasciitis. High Resolution Chest CT This is a specialized CT of the lungs performed without IV contrast. Gothner M, Dudda M, Kruppa C, Schildhauer TA, Swol J. Fulminant necrotizing fasciitis of the thigh, following an infection of the sacro-iliac joint in an immunosuppressed, young woman, MRI in necrotizing fasciitis of the extremities. Skeletal Radiol. Summary of imaging findings of necrotizing fasciitis. CT Head or brain with and without contrast Note: MRI Brain with/without contrast is preferred. They are used for bowel opacification and are not nephrotoxic. Contrast agents can be further classified as high or low osmolality, based on the iodine concentration. The CT and MRI findings in the spectrum of musculoskeletal infections are discussed and contrasted, and pitfalls in their evaluation of musculoskeletal infection are described. Contrast enhancement is also used to evaluate superior vena cava syndrome. Epidemiology Risk factors trauma foreign bodies 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. 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. Kidney/ureteral stones With IV contrast 1. The concentration of barium determines whether it enhances the diagnosis or causes an artifact and obscures pathology. If the infection spreads to deeper tissues, complications can occur, such as soft-tissue abscess,necrotizing fasciitis,infectious myositis, and/or osteomyelitis. Author disclosure: No relevant financial affiliations. 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. One of these questions that came up frequently related to CT scans was Do I need contrast?. Check for errors and try again. 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. Cellulitis can affect any region of the body, and commonly affects a lower limb. 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. 2nd ed. Imaging of Musculoskeletal Soft Tissue Infections. Yu J & Habib P. MR Imaging of Urgent Inflammatory and Infectious Conditions Affecting the Soft Tissues of the Musculoskeletal System. This question is for testing whether or not you are a human visitor and to prevent automated spam submissions. This can be filled at Baystate Pharmacies at 759 Chestnut Street and 3300 Main Street as well as at many local pharmacies. Normally the subcutaneous tissue is hypoechoic with few hyperechoic strands (representing connective tissue). Cellulitis(rare plural: cellulitides) is an acute infection of the dermis and subcutaneous tissues without deep fascial or muscular involvement. Speak with a Radiologist: 541-284-4016 sharing sensitive information, make sure youre on a federal 2004;350(9):904-12. Since the epidermis is not involved, cellulitis is not transmitted by person-to-person contact. FOIA Contrast enhancement of the pulmonary arteries is key, as embolic disease is identified as abnormal filling defects within the pulmonary arteries (Figure 2). Large volume of gas seen within the scrotum wall and scrotum sac on the scout image (curved black arrow), consistent with Fourniers gangrene. Kirchgesner T, Tamigneaux C, Acid S et al. Enter multiple addresses on separate lines or separate them with commas. Fluid tracking along deep and intermuscular fascia, which can be seen in advanced cases (d). It is also not used in patients with suspected acute stroke. (ABRS) may develop orbital, intracranial, and vascular complications including orbital cellulitis, subperiosteal , abscess, intracranial abscess, cerebritis, cavernous sinus thrombosis and aneurysm. Turecki M, Taljanovic M, Stubbs A et al. N.p. However, patients with a documented anaphylactic reaction to any medication are at higher risk of a reaction to iodinated contrast.9,10, Many centers screen outpatients with suspected renal insufficiency by measuring serum creatinine one month before administration of contrast agents. 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.3. Even in osseous infection, CT and MRI can give better anatomic delineation of the extent of infection. 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. endobj When is contrast needed for abdominal and pelvic CT? Ultrasound is usually the first investigation to evaluate a clinical suspicion of cellulitis. The https:// ensures that you are connecting to the Orbital cellulitis. Suspected Osteomyelitis, Septic Arthritis, or Soft Tissue Infection (Excluding Spine and Diabetic Foot) endobj no financial relationships to ineligible companies to disclose. This risk is significantly increased in patients with chronic renal disease, diabetes, heart failure, and anemia. 2019;10(1):47. Stadelmann VA, Potapova I, Camenisch K, Nehrbass D, Richards RG, Moriarty TF. Axial non-contrast. MeSH 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. In B, the native left lung is small, with evidence of bronchiectasis, bronchiolectasis, and areas of honeycombing (black arrow). 1. The soft-tissue air deep to the fascia is seen as multiple echogenic foci (arrows) on ultrasound study (b). In patients with normal renal function, repeat measurement of serum creatinine is not recommended after outpatient administration of IV contrast agents.7. %PDF-1.7 Skeletal Radiol. Skin findings, pain out of proportion, and signs of systemic shock should alert the clinician to the possibility of necrotizing fasciitis. AJR Am J Roentgenol. Extensive streaky soft-tissue gas is seen extending along the fascial planes of the right thigh on radiograph. The overall PPV for the prediction of deep neck abscess with contrast-enhanced CT was 79.6%. 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. MR Imaging in Acute Infectious Cellulitis. 1Department of Radiology, Massachusetts General Hospital, Boston, MA, USA. As a library, NLM provides access to scientific literature. 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. CT area of interest without IV contrast Usually Appropriate Varies Variant 7: Suspected soft tissue infection. Infection, inflammation, and edema of the lung parenchyma are usually well depicted on CT without contrast enhancement. It is usually due to underlying bacterial sinusitis. {"url":"/signup-modal-props.json?lang=gb"}, Radswiki T, Carroll D, Knipe H, et al. . Cellulitis. 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. Emergency Medicine: Clinical Essentials. Normally the subcutaneous tissue is hypoechoic with few hyperechoic strands (representing connective tissue). myriad of non-infective erythematous rashes, ADVERTISEMENT: Supporters see fewer/no ads, Please Note: You can also scroll through stacks with your mouse wheel or the keyboard arrow keys. Fasciae of the Musculoskeletal System: MRI Findings in Trauma, Infection and Neoplastic Diseases. 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. {"url":"/signup-modal-props.json?lang=us"}, Radswiki T, Carroll D, Knipe H, et al. Possible contraindications for using intravenous contrast agents during computed tomography include a history of reactions to contrast agents, pregnancy, radioactive iodine treatment for thyroid disease, metformin use, and chronic or acutely worsening renal disease. 2015;2015:587857. doi: 10.1155/2015/587857. Cellulitis(rare plural: cellulitides) is an acute infection of the dermis and subcutaneous tissues without deep fascial or muscular involvement. 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. AJR Am J Roentgenol. 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. 2. Please enable it to take advantage of the complete set of features! 7. Infect Dis Clin North Am. The need for enhancement with intravenous (IV) contrast depends on the specific clinical indication (Table 1). 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 CT pulmonary angiography with intravenous contrast in a patient being evaluated for arteriovenous malformation. Radiologic Approach to Musculoskeletal Infections. The information provided is for educational purposes only. 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. 2022 Nov 25;10(12):2329. doi: 10.3390/microorganisms10122329. Initial radiographs show soft tissue gas (without puncture wound) or are normal with high clinical suspicion of necrotizing fasciitis. The American College of Radiology proposes a three-tiered risk assessment for patients receiving metformin in whom IV contrast is to be administered (Table 3).7 Many institutions have their own protocols for metformin administration with IV contrast, so physicians should be aware of the standard of care in their community. The most common are baruim and iodine based. 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.