STIR imaging of synthetic vascular graft infection

Me, Hansen; Ek, Yucel; Ac, Waltman

doi:10.1007/bf02603034

Cited by 12 publications

(7 citation statements)

References 30 publications

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“…Basic “edema‐weighted” magnetic resonance (MR) imaging has been shown to be highly sensitive in demonstrating areas of extracellular fluid, which manifest as increased signal intensity compared with surrounding normal tissue. These sequences have been used to identify tissue edema, with or without inflammation, in patients with musculoskeletal diseases (6), tumors (7), liver disease (8) and vascular graft infections (9). Recent methodologic developments have permitted tissue characterization, including detection of edema, to be performed rapidly and relatively free of artifacts (10, 11).…”

mentioning

confidence: 99%

Takayasu arteritis: Utility and limitations of magnetic resonance imaging in diagnosis and treatment

Tso

Flamm

White

et al. 2002

Arthritis & Rheumatism

286

138

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Objective. Previous studies have confirmed the poor correlation of symptoms, signs, and levels of acute-phase reactants with disease activity in ϳ50% of all patients with Takayasu arteritis (TA). Invasive angiographic studies demonstrate vessel lumen anatomy, but do not provide qualitative information about the vessel wall. Moreover, sequential invasive angiographic studies expose patients to high-dose ionizing radiation and catheter/procedure-related morbidity. The aim of the present study was to determine the utility of new developments in vascular magnetic resonance (MR) technology in patients with TA.Methods. Electrocardiogram-gated "edemaweighted" MR was used to evaluate the aorta and its primary branches with regard to the vascular lumen, vessel wall anatomy, and vessel wall edema in 24 TA patients (77 studies). Inclusion criteria were age <50 years and features of TA on both clinical examination and invasive angiographic studies. Patients were stratified based on clinical and laboratory indications of having either unequivocally active disease, inactive disease, or uncertain disease status.Results. MR revealed vessel wall edema in 94% (17 of 18), 81% (13 of 16), and 56% (24 of 43) of studies obtained during periods of unequivocally active disease, uncertain disease activity, and apparent clinical remission, respectively. Westergren erythrocyte sedimentation rate and C-reactive protein values did not correlate with either the clinical assessment of disease activity or MR evidence of vascular edema. The frequency of presumed vascular inflammation (edema), as assessed by MR, in patients who appeared to be in remission was similar to the reported frequency of new angiographic lesions and histopathologic evidence of active disease in surgical specimens from patients thought to be in remission. However, the presence of edema within vessel walls did not consistently correlate with the occurrence of new anatomic changes found on subsequent studies.Conclusion. Inconsistencies in the presence or absence of vessel edema and subsequent anatomic changes have cast doubt on the utility of edemaweighted MR imaging as a sole guide to disease activity and treatment in TA. In this study, the greatest utility of MR was in providing a safe, noninvasive means of assessing changes in vascular anatomy.

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mentioning

confidence: 99%

Takayasu arteritis: Utility and limitations of magnetic resonance imaging in diagnosis and treatment

Tso

Flamm

White

et al. 2002

Arthritis & Rheumatism

286

138

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“…It has been argued that these MR relaxation time variations may reflect tissue changes caused by alterations in the tissue's macromolecular structure. This structural modification can be induced by the body's inflammatory response or healing process (41,43,45) or even by pathological changes (46,47). In a previous study (44), we demonstrated the correlation between the variations in the progressive pattern of T 2s and the tissue's inflammatory response.…”

Section: Discussionmentioning

confidence: 57%

“…Various authors have reported the lack of correlation between MR relaxation time variations and total tissue water content (41,43,45–47). It has been argued that these MR relaxation time variations may reflect tissue changes caused by alterations in the tissue's macromolecular structure.…”

Section: Discussionmentioning

confidence: 99%

“…These features have led MR relaxometry techniques to be used extensively in vivo and in vitro to investigate tissue properties (40). They have been shown to be very sensitive in monitoring the changes in the tissue caused by irradiation (41), inflammation (42–44), and other pathologies (45–47). MR relaxation times are sensitive to changes in the tissue total water content, collagen, fibrin, and other protein concentrations, as well immunological cell concentrations, and consequently, the inflammatory response and healing process.…”

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confidence: 99%

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Tissue Reactions to Polypyrrole‐Coated Polyesters: A Magnetic Resonance Relaxometry Study

et al. 1999

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The electrically conductive properties of polypyrrole (PPy) as a coating on polyester material are very attractive for the manufacture of small diameter blood conduits. However, before these PPy-coated materials can be investigated for their capacity to generate endothelialized luminal surfaces, they must first be studied for their innocuousness in a living environment. The specific goal of the present study was to investigate the in vivo interactions of PPy-coated and noncoated woven polyester materials implanted subcutaneously in rats for prescheduled periods of 2, 5, 10, 20, and 30 days. The in vivo magnetic resonance (MR) relaxation times were computed for a small area of muscle tissue adjacent to the implants. A correlation was concurrently attempted with blood monocyte activation studies as well as histological observations of the tissue-material interface. The progressive pattern of the slower transversal relaxation time (T2s) values revealed a more persistent tissue reaction for the most conductive PPy-coated materials and a shorter acute tissue response as the surface resistivity increased. Similarly, the blood monocyte activation studies indicated that the thickness of the PPy coating, which correlated with the conductivity, was directly related to tissue response. Furthermore, both the MR and biological studies showed that the PPy-coated material with a high surface resistivity displayed the lowest tissue reaction over the entire period of implantation. The results obtained from the blood monocyte activation studies and histological observations correlate well with the noninvasive MR measurements of the body's healing process. The conductive materials with high surface resistivities must be further investigated. Finally, the noninvasive nature of MR relaxometry reveals its outstanding potential for future in vivo investigations of the body's tissue interactions with polymers and nonferromagnetic biomaterials.

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“…35 Signs of infection include lack of incorporation of the graft into adjacent tissues, false aneurysm, fluid collection adjacent to the graft, perigraft tissue inflammation and gas adjacent to the graft. 36,37 The accuracy of CT scanning tends to be higher in advanced graft infections but is lower in lowgrade infections. In aortic graft infections, one study showed CT to have a sensitivity of 94% and specificity of 85% when the criteria of perigraft fluid, perigraft soft tissue attenuation, ectopic gas, pseudoaneurysm or focal bowel wall thickening were used.…”

Section: Computerized Tomography and Magnetic Resonance Imagingmentioning

confidence: 99%

Diagnosis and management of staphylococcal infections of vascular grafts and stents

Chambers¹

2005

Internal Medicine Journal

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Staphylococcus aureus and coagulase-negative staphylococci are the commonest bacterial causes of both vascular graft and stent infections. Infection may occur either from direct implantation or haematogenous spread, and occurs in less than 1% of aortic grafts, 2% to 5% of inguinal grafts, and rarely in stents. Death or amputation is common following these infections despite aggressive treatment. Infection with S. aureus is usually more acute than with coagulase-negative staphylococci but both cause systemic symptoms. Inguinal infections usually cause localized swelling often with a sinus tract, bleeding or distal embolism. Aortic infections commonly present with abdominal discomfort retroperitoneal infection or a mass from a false aneurysm. Stent infections usually cause pain, swelling, erythema and circulation disturbances of the ipsilateral limb. The most useful investigations are blood cultures and computerized tomography or magnetic resonance imaging. These imaging techniques have a high sensitivity and specificity in advanced graft infections but these are considerably lower in low-grade infections. Persistence of perigraft fluid beyond 3 months after surgery is suspicious of infection. Aggressive antimicrobial therapy is an important part of management but surgery is usually required to cure both graft and stent infections. Where the organisms are susceptible, high-dose beta-lactam therapy (e.g. flucloxacillin, dicloxacillin or a first-generation cephalosporin) plus low-dose gentamicin are recommended initially. Some authorities add rifampicin after 3-5 days treatment, but this is controversial. Antimicrobial therapy can be stopped 4-6 weeks after surgery if arterial stump cultures are negative but should be continued long-term, and perhaps indefinitely, if they are positive.

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STIR imaging of synthetic vascular graft infection

Cited by 12 publications

References 30 publications

Takayasu arteritis: Utility and limitations of magnetic resonance imaging in diagnosis and treatment

Takayasu arteritis: Utility and limitations of magnetic resonance imaging in diagnosis and treatment

Tissue Reactions to Polypyrrole‐Coated Polyesters: A Magnetic Resonance Relaxometry Study

Diagnosis and management of staphylococcal infections of vascular grafts and stents

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