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Perianal Sepsis in Hematologic Malignancy: MR Imaging Appearances and Distinction from Cryptoglandular Infection in
Andrew A Plumb1, Steve Halligan1, Gauraang Bhatnagar1
1From the Centre for Medical Imaging, University College London, Podium Level 2, University College Hospital, 235 Euston Rd, London, NW1 2BU.
Purpose:
To use magnetic resonance (MR) imaging to document the appearance of perianal infection in patients with a hematologic malignancy (HM) compared with that in immunocompetent control patients.
Materials And Methods:
After an ethical waiver was obtained, 38 patients with an HM were matched by age and sex to 38 control patients with no history of immunocompromise or Crohn disease. Both groups had undergone MR imaging for perianal symptoms and/or systemic sepsis. Two radiologists who were blinded to the diagnosis independently reviewed the MR images and recorded the size and distribution of abscesses and/or fistula tracts, the extent of perianal edema, and the likely diagnosis. Groups were compared by using the Mann-Whitney-Wilcoxon, χ(2), or Fisher exact test. Receiver operating characteristic (ROC) curves were constructed to estimate the ability of MR imaging to help distinguish patients with an HM from control patients.
Results:
Patients with an HM had significantly greater perianal edema than did control patients (mean arc angle of anal canal involved, 220° vs 60°; P < .001). However, they had significantly lower rates of fistula (15 [39.5%] vs 35 [92.1%] of 38; P < .001). Abscesses were similar in frequency (10 [26.3%] vs 17 [44.7%] of 38; P = .15) and were unrelated to the degree of neutropenia (P = .71) or the use of chemotherapy (P = .10). Surgical treatment was rarely required in patients with an HM, either during the acute illness (four [10.5%] of 38) or thereafter (three [7.9%] of 38). MR imaging had an excellent ability to help discriminate patients with HM from immunocompetent patients (areas under the ROC curve, 0.91 and 0.97).
Conclusion:
Perianal infection in patients with an HM is more likely to cause diffuse perianal edema and is less likely to cause fistulas than in immunocompetent patients. MR imaging can help distinguish patients with an HM from those without immunocompromise.
Insights
Magnetic resonance (MR) imaging reveals that perianal infections in patients with hematologic malignancy (HM) typically present with more diffuse edema and fewer fistulas compared to immunocompetent individuals. MR imaging effectively differentiates these patient groups.
Area of Science:
- Radiology
- Oncology
- Infectious Disease
Background:
- Perianal infections are common complications in patients with hematologic malignancies (HM).
- Distinguishing the imaging characteristics of perianal infections in HM patients from immunocompetent individuals is crucial for appropriate management.
- Magnetic resonance (MR) imaging is a key modality for evaluating perianal conditions.
Purpose of the Study:
- To compare the MR imaging appearance of perianal infections in patients with HM versus immunocompetent controls.
- To assess the diagnostic performance of MR imaging in differentiating these two groups.
Main Methods:
- A retrospective case-control study matched 38 HM patients with 38 immunocompetent controls based on age and sex.
- All patients underwent MR imaging for perianal symptoms or sepsis.
- Two blinded radiologists analyzed MR images for abscesses, fistulas, and edema, comparing findings between groups using statistical tests and ROC curves.
Main Results:
- Patients with HM exhibited significantly greater perianal edema (220° vs 60°) but significantly lower rates of fistula formation (39.5% vs 92.1%) compared to controls.
- Abscess frequency was similar between groups and unrelated to neutropenia or chemotherapy.
- MR imaging demonstrated excellent ability to distinguish between HM patients and controls (AUCs 0.91 and 0.97).
Conclusions:
- Perianal infections in HM patients are characterized by more diffuse edema and less frequent fistulas than in immunocompetent individuals.
- MR imaging is a valuable tool for differentiating perianal infections in HM patients from those in immunocompetent individuals.
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