1182 AJR:196, May 2011 chronicity. Acute hematogenous osteomyeli- tis is usually successfully treated with a 4- to 6-week course of antibiotics; however, if signs of infection do not abate, possible com- plications should be considered, such as the presence of a subcutaneous, subperiosteal, or intramedullary abscess; the formation of a sequestrum; or the presence of foreign mate- rial that would require surgery. Chronic os- teomyelitis generally cannot be eradicated without surgical treatment [6–8]. Interventional radiology techniques have gained considerable acceptance in the med- ical, surgical, and oncology communities. Treatment of Deep Intramuscular and Musculoskeletal Abscess: Experience With 99 CT-Guided Percutaneous Catheter Drainage Procedures Carmel G. Cronin 1 Debra A. Gervais Peter F. Hahn Ronald Arellano Alexander R. Guimaraes Peter R. Mueller Cronin CG, Gervais DA, Hahn PF, Arellano R, Guimaraes AR, Mueller PR 1 All authors: Department of Abdominal Imaging and Interventional Radiology, Massachusetts General Hospital, Harvard Medical School, White 270, 55 Fruit St, Boston, MA 02214. Address correspondence to C. G. Cronin (cgcronin@partners.org). Vascular฀and฀Interventional฀Radiology฀•฀Original฀Research AJR 2011; 196:1182–1188 0361–803X/11/1965–1182 © American Roentgen Ray Society D espite advances in medical knowl- edge, imaging techniques, and surgical interventions, musculo- skeletal infection remains a chal- lenging problem that may elude diagnosis and receive suboptimal management. In the current literature, there is some disagreement about the management of bone and joint infections [1]. In general, superficial and deep muscle abscesses, septic joints, diskitis, and epidural abscess are most commonly treated with a combination of antibiotics and surgical inci- sion and drainage [2–5]. On the other hand, osteomyelitis is managed depending on its Keywords: abdominal drainage, muscle abscess, musculoskeletal collection DOI:10.2214/AJR.09.4082 Received December 3, 2009; accepted after revision November 27, 2010. OBJECTIVE. The purpose of this article is to describe our experience draining deep muscular and musculoskeletal abscess collections with CT guidance, emphasizing clinico- pathologic factors associated with drain failure, and to further analyze patient outcomes ac- cording to whether the process involves muscle alone or also involves adjacent bone or joint (skeletal involvement). MATERIALS฀AND฀METHODS. The details of percutaneous catheter drainage were retrospectively recorded for all drainages performed over a 9-year period. The technical and clinical successes of percutaneous catheter drainage were determined. Multifactor logistic regression analysis was used to identify predictors of drain failure (malignancy, age, chemo- therapy, surgery, infection, complexity, size, days in situ, and skeletal involvement). These parameters were assessed in all patients, those with muscle involvement alone and those with musculoskeletal collections. RESULTS. Eighty-nine of 94 patients underwent one percutaneous drainage procedure and 5 of 94 patients underwent two drainages for a total of 99 drainages in 94 patients (one drain- age [n = 89] and two drainages [n = 5]). There were 62 men and 32 women with a mean age of 58.5 years (age range [±SD], 22.3–88.0 ± 16 years). The abscess diameters ranged from 1.8 to 13 cm (mean, 5.3 ± 2.5 cm), volume aspirated ranged from 0 to 200 mL (mean, 45 ± 44 mL), and mean duration of drainage was 16.2 days (range, 2–110 ± 18.7 days). The iliopsoas muscle was the most common site of drainage, accounting for 87.8% of the total. Catheter insertion was possible in all patients, with the muscular component successfully drained in 82% (81/99) over- all: 85% (46/54) of those with muscle involvement alone and 77% (35/45) of those with muscu- loskeletal collections. Catheter drainage and antibiotic administration resulted in 65.6% (65/99) not requiring any surgical intervention and resolution of abnormal white cell count or fevers in 98.8% (79/80) of those with abnormal parameters before treatment. Skeletal infection was as- sociated with increased risk of drainage failure ( p = 0.0001). CONCLUSION. Percutaneous imaging-guided musculoskeletal drainage is clinically useful, safe, and effective for draining complex musculoskeletal collections. It is highly effec- tive for draining collections involving muscle alone; however, skeletal infection is associated with a higher risk of drain failure. Cronin et al. CT Guidance in Deep Muscular and Musculoskeletal Abscess Vascular and Interventional Radiology Original Research