primary soft tissue infections 11-09.ppt (read-only) · cellulitis !!cellulitis is acute...
TRANSCRIPT
Imaging of Primary Soft Tissue Infections in the
Pediatric Patient
Christopher S. Bang, D.O. Shannon Nedelka, M.D.
Gwy Suk Seo, M.D. Johnny U.V. Monu, M.D.
University of Rochester Medical Center
Rochester, NY Presentation material is for education purposes only. All rights reserved. ©2004 URMC Radiology Page 1 of 80
Introduction
!! Prior to the advent and widespread availability of magnetic resonance imaging (MRI), diagnosis of soft tissue inflammation was frequently clinical and often delayed
!! MRI enables prompt and accurate diagnosis of soft tissue infections and decreases morbidity and mortality
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Introduction
!! Soft tissue inflammation is often seen in the setting of osteomyelitis
!! This presentation addresses soft tissue infection that occurs in the absence of osteomyelitis
!! Soft tissue infections occurring in a setting of prior surgery, presence of prosthesis and immune depressive states are also excluded
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Purpose
!! Demonstrate various patterns of primary soft tissue inflammation occurring in otherwise healthy pediatric patients
!! Review the MRI findings, discuss the differential diagnosis and pathogenesis
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Signs and Symptoms
!! Patients usually have systemic signs and symptoms including fever, night sweats, and leukocytosis
!! Patients also present with focal symptoms such as swelling, erythema, pain and tenderness
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Soft Tissue Inflammation
!! Cellulitis
!! Fasciitis
!! Myositis
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Cellulitis
!! Cellulitis is acute inflammation of the skin and superficial subcutaneous tissue
!! Diagnosis is often clinical
!! MRI aids in detection of extension into the underlying fascia (fasciitis) and muscle (myositis), and presence of concurrent abscesses
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Fasciitis
!! Fasciitis is non-specific inflammation of the deeper subcutaneous tissues and muscle sheath
!! Commonly associated with cellulitis or myositis
!! Necrotizing form due to flesh-eating or gas-forming bacterial infection
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Myositis
!! Normal muscle is inherently resistant to infection
!! Myositis is acute inflammation of the
muscles, commonly seen in the setting of osteomyelitis, immune depression, or trauma
!! Primary pyomyositis is uncommon in an
otherwise healthy patient Presentation material is for education purposes only. All rights reserved. ©2004 URMC Radiology Page 9 of 80
MR Imaging Protocol
!! T2-weighted (long TR and TE) images in both axial and longitudinal planes !! Fast Spin Echo (FSE) sequences with fat saturation
are used at our institution !! Inversion Recovery (IR) sequences may also be used
!! T1-weighted (short TR and TE) images in longitudinal plane
!! Intravenous contrast is often helpful !! Pre and post contrast fat saturated T1-weighted
images in axial plane Presentation material is for education purposes only. All rights reserved. ©2004 URMC Radiology Page 10 of 80
Case 1
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2 year old with left leg swelling and erythema
Fat-Suppressed T2-Weighted Image (T2W)
Fat-Suppressed T1-Weighted Image Post-Gadolinium (Post-contrast T1W)
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!! Diffuse high signal intensity of the skin and superficial subcutaneous tissue on T2-weighted imaging
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!! Diffuse enhancement of the same tissues on post-contrast images
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Cellulitis
Coronal T2W Axial Post-contrast T1W
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Case 2
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6 year old with right elbow swelling and erythema
T2W Post-contrast T1W Proton density T1W
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!! Proton density image (left) and T1-weighted image (right) demonstrate low signal collection within the thickened subcutaneous tissue posterior to the olecranon
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!! T2-weighted image (left) and post-contrast image (right) demonstrate abscess (arrows) with peripheral enhancement within inflamed subcutaneous tissue
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Cellulitis with Abscess
T2W Post-contrast T1W Proton density T1W
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Case 3
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11 year old with right forearm pain and swelling
Sagittal and axial T2W Presentation material is for education purposes only. All rights reserved. ©2004 URMC Radiology Page 22 of 80
!! Diffuse inflammation of the skin and subcutaneous tissues (arrows) as well as within the fascial planes
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!! Diffuse inflammation of the skin and subcutaneous tissues as well as within the fascial planes
!! Focal irregular collection in the volar aspect of the forearm (arrow)
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!! Diffuse inflammation of the skin and subcutaneous tissues (arrows)
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!! Diffuse inflammation of the skin and subcutaneous tissues as well as within the fascial planes (arrows)
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!! Diffuse inflammation of the skin and subcutaneous tissues as well as within the fascial planes
!! Focal abscess in the volar aspect of the forearm (arrow)
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Fasciitis with Abscess
T2W Presentation material is for education purposes only. All rights reserved. ©2004 URMC Radiology Page 28 of 80
Case 4
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11 year old with right hip pain
T2W Post-contrast T1W
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!! High T2-weighted signal involving an inflamed right obturator internus muscle (arrow)
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!! Post-contrast enhancement of the right obturator internus muscle (arrow)
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Focal Pyomyositis
T2W Post-contrast T1W
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Case 5
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5 year old with right hip pain
T2W Post-contrast T1W T1W Presentation material is for education purposes only. All rights reserved. ©2004 URMC Radiology Page 35 of 80
!! Diffusely enlarged vastus lateralis muscle with multiple subtle hypointense foci (arrows)
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!! T1W images show diffusely enlarged vastus lateralis muscle with multiple subtle hypointense
foci (arrows) Presentation material is for education purposes only. All rights reserved. ©2004 URMC Radiology Page 37 of 80
!!T2W images show diffuse heterogeneous high signal within swollen vastus lateralis muscle (arrows)
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!!T2W images show diffuse heterogeneous high signal within swollen vastus lateralis muscle (arrows)
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!!Multiple high signal collections with peripheral ring of low signal (arrows)
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!!Multiple high signal collections with peripheral ring of low signal (arrows)
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!!Another high signal focus in the biceps femoris muscle (arrows)
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!!Diffuse contrast enhancement of the vastus lateralis muscle and focal enhancement of the
biceps femoris muscle Presentation material is for education purposes only. All rights reserved. ©2004 URMC Radiology Page 43 of 80
!!Diffuse contrast enhancement of the vastus lateralis muscle (arrows) and focal enhancement of
the biceps femoris muscle (arrow) Presentation material is for education purposes only. All rights reserved. ©2004 URMC Radiology Page 44 of 80
!!Peripherlly enhancing collections in the vastus lateralis muscle (arrows) and in the biceps
femoris muscle (arrow) Presentation material is for education purposes only. All rights reserved. ©2004 URMC Radiology Page 45 of 80
Multifocal Pyomyositis with Microabscesses
T2W Post-contrast T1W T1W Presentation material is for education purposes only. All rights reserved. ©2004 URMC Radiology Page 46 of 80
Case 6
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5 y.o with right knee pain and swelling
Coronal T2W Presentation material is for education purposes only. All rights reserved. ©2004 URMC Radiology Page 48 of 80
T2W
Post-contrast T1W
5 y.o with right knee pain and swelling
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!! Diffuse heterogeneous high signal in the quadriceps, hamstrings and calf muscles
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!! Diffuse heterogeneous high signal in the vastus lateralis and medialis (VL, VM), biceps femoris semimembranosus medial and lateral heads gastrocnemius muscles, and the surrounding
deep fascia with joint effusion
VL! !VM
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!! Diffuse heterogeneous high signal in the vastus lateralis and medialis biceps femoris (BF),
semimembranosus (SM), medial and lateral heads gastrocnemius muscles, and the
surrounding deep fascia with joint effusion
BF!
SM!
BF!
!SM
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!! Diffuse heterogeneous high signal in the vastus lateralis and medialis, biceps femoris,
semimembranosus, medial and lateral heads gastrocnemius (MG, LG) muscles, and the surrounding deep fascia, with joint effusion
LG! !MG
!MG ⁄ LG
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!! Diffuse heterogeneous high signal in the vastus lateralis and medialis, biceps femoris,
semimembranosus, medial and lateral heads gastrocnemius muscles, and the surrounding deep fascia (arrows), with joint effusion (JE)
!JE !JE
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!! Small collections in the gastrocnemius muscles (arrows)
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!! Heterogeneous enhancement of the quadriceps, hamstring and calf muscles, and the
surrounding deep fascia
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T2W
Post-contrast T1W
Diffuse Pyomyositis and Fasciitis with Microabscesses
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Case 7
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10 year old with left knee pain
T2W Post-contrast T1W Presentation material is for education purposes only. All rights reserved. ©2004 URMC Radiology Page 59 of 80
!!Inflammation near the insertion site of the Pes anserinus (sartorius, gracilis and semitendinosus) tendons, bursa (arrows) and popliteus muscle
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!!Inflammation near the insertion site of the Pes anserinus (sartorius, gracilis and semitendinosus) tendons, bursa and popliteus muscle (arrowhead)
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!!Enhancement near the insertion site of the Pes anserinus (sartorius, gracilis and semitendinosus) tendons, bursa (arrow) and popliteus muscle
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!!Enhancement near the insertion site of the Pes anserinus (sartorius, gracilis and semitendinosus) tendons, bursa and popliteus muscle (arrowhead)
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Myositis, Tendonitis, Bursitis
T2W Post-contrast T1W Presentation material is for education purposes only. All rights reserved. ©2004 URMC Radiology Page 64 of 80
Case 8
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11 year old with right shoulder pain and fever
Post-contrast T1W Axial and Sagittal T2W
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!! High signal collection in the anterior supraclavicular region (arrows) and surrounding inflammation
involving the rotator cuff muscles and subcutaneous tissues
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!! Peripherally enhancing multiloculated abscess (arrows) and surrounding inflammation involving the
rotator cuff muscles and subcutaneous tissues
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!! Peripherally enhancing multiloculated abscess and surrounding inflammation involving the rotator cuff muscles (ss-supraspinatus, sc-subscapularis) and
subcutaneous tissues (arrow)
ss
sc
ss
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Pyomyositis with Abscess
Post-contrast T1W T2W
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Cellulitis - MRI Findings !! Diffuse or reticular pattern of increased
signal of thickened tissue on T2-weighted images
!! Post-gadolinium images show enhancement of affected tissue and peripheral enhancement of abscess cavities
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Fasciitis - MRI Findings !! In addition to features of cellulitis there is
increased signal in deep soft tissue excluding the muscles on T2-weighted images
!! Post-gadolinium images show enhancement of affected tissue
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Myositis - MRI Findings !! Diffuse muscle enlargement
!! T1-weighted images show low signal or possible reticular or peripheral high signal
!! T2-weighted images show diffuse high signal
!! Post-gadolinium images show enhancement of affected tissue and peripheral enhancement of abscess cavities
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Differential Diagnosis !! Includes: •! Infection: Osteomyelitis, Septic arthritis,
Bursitis
•! Trauma: Hematoma, Subacute muscle tear, Bursitis
•! Neoplastic: Sarcoma, Lymphoma, Congenital generalized fibromatosis (Desmoid tumor)
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Discussion !! Isolated soft tissue infections in the
pediatric age group may be focal, multi-focal or diffuse
!! The skin and superficial subcutaneous tissues may only be involved - Cellulitis
!! The deep subcutaneous tissues and muscle sheath may be affected - Fasciitis
!! Muscle may be involved - Pyomyositis Presentation material is for education purposes only. All rights reserved. ©2004 URMC Radiology Page 75 of 80
Discussion !! More than one soft tissue element is
commonly involved, but isolated infection may occur
!! Concurrent abscesses may occur
!! Other associated findings may include tendonitis, bursitis, joint effusion
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Discussion
!! Common pathogens include Streptococcus pyogenes and Staphylococcus aureus, but cultures are not always positive due prior antibiotic treatment
!! Imaging is very useful for treatment planning such as percutaneous or surgical drainage and debridement
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Conclusion !! Primary musculoskeletal soft tissue
infections, especially involving the deeper structures, in otherwise healthy pediatric population are uncommon, but awareness is crucial
!! MRI is beneficial in these cases, aiding prompt diagnosis, encouraging adequate treatment and decreasing morbidity
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References !! Bickels et al: Primary Pyomyositis. The Journal of Bone and Joint Surgery 2002; 84A
(12): 2277-2286.
!! Burgener et al: Soft Tissue Disease in Differential Diagnosis in Magnetic Resonance Imaging. Thieme, New York, 2002.
!! Gubbay and Isaacs: Pyomyositis in Children. The Pediatric Infectious Disease Journal 2000; 19(10): 1009-1012.
!! Kothari et al: Pediatric Musculoskeletal Radiology: Imaging of Musculoskeletal Infections. Radiologic Clinics of North America 2001; 39(4): 653-671.
!! Linklater and Potter: Emergent Musculoskeletal Magnetic Resonance Imaging. Applied Radiology Supplement 2000; 29(3): 87-107.
!! Resnick and Niwayama: Osteomyelitis, Septic Arthrirtis and Soft Tissue Infection in Diagnosis of Bone and Joint Disorders, 3rd Edition, Volume 4. WB Saunders, Philadephia, 1995.
!! Struk et al: Imaging of Musculoskeletal and Spinal Infections: Imaging of Soft Tissue Infections. Radiologic Clinics of North America 2001; 39(2): 277-303.
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Thank you.
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