Clinical cases in image-guided drainage

Selection of image guidance modality

The success of a surgical intervention is largely determined by the choice of modality.

Computed tomography (CT) is the method of choice for deep-seated fluid collections. It provides high spatial resolution, clearly demonstrating lesion borders, abscess capsule thickness, adjacent organs, and a safe needle trajectory. A disadvantage of the method is the difficulty of real-time instrument manipulation, as scanning is limited to the axial plane. To expand capabilities, gantry tilting (gantry tilting) in the cranial or caudal direction is used, which requires mandatory use of a laser centering device.

Ultrasound (US) provides high-resolution real-time dynamic guidance. However, the method has severe limitations in the presence of gas in tissues or when the target organ is shielded by gas-filled bowel loops.

A modern alternative is cone-beam CT (Cone-beam CT), available on angiographic systems. The method allows the generation of 3D volumetric images and their software fusion (fusion) with fluoroscopy. This reduces procedure time without sacrificing diagnostic quality.

Patient preparation and management

Proper preoperative preparation is critical for safety. According to SIR guidelines, broad-spectrum medications are administered strictly within 1 hour prior to the start of the procedure. If the interval exceeds 3 hours, the risk of infection increases fivefold. At the same time, early antibiotic administration does not distort bacteriological culture results, as the dense abscess wall isolates the purulent contents from the systemic circulation.

Since drainage often requires conscious sedation, strict fasting rules similar to general anesthesia apply: no solid food for 6 hours, no liquids for 2 hours.

The sedation protocol recommended by the authors includes:

• Fractional administration of fentanyl citrate (25 mcg each);
• Administration of midazolam (0.5–1 mg) to the desired level of sedation;
• Use of antiemetic drugs.

Following catheter placement, the patient must be closely monitored with continuous vital sign assessment for at least 4 hours.

Abdominal interventions

Let's review the features of percutaneous interventions in specific organs.

Gallbladder. Percutaneous cholecystostomy has a low mortality rate (around 2%), making it life-saving for critically ill patients. Access through the liver parenchyma rather than directly through the abdominal wall is considered optimal. The transhepatic tract secures the catheter more reliably and minimizes the risk of bile leakage and peritonitis. In calculous cholecystitis, the catheter is left in place until planned surgery. In acalculous inflammation, it can be removed after 6 weeks if the patient is stable, the cystic duct is patent, and the fistulous tract is securely formed.

Spleen. Fluid collections here most commonly occur against the background of endocarditis, sickle cell anemia, trauma, or immunodeficiency. If the abscess is surrounded by a layer of healthy parenchyma, its percutaneous drainage is technically safe. This preserves the organ and avoids splenectomy, which puts the patient at risk of severe sepsis and accelerated atherosclerosis development. Peripheral locations, as well as lesions in the upper and lower poles, are the easiest to puncture.

Liver and retroperitoneal space. Complex hematomas (e.g., in segment VI of the liver) are successfully treated under ultrasound guidance. For more complex cases, such as a psoas abscess (psoas abscess) with gas and secondary hydronephrosis, CT guidance with a "quick-check" fast scanning mode is used for safe needle advancement.

Drainage of pelvic collections

Specific approaches are used to evacuate fluid from the pelvic cavity (e.g., after rectal resection).

Intracavity methods (transrectal and transvaginal). Performed with endocavity probes in the patient's lateral position. The catheter is placed using the free-hand technique, through an introducer, or via a built-in guide. The main rule: apply only minimal pressure on the probe to avoid compressing or puncturing the walls of the bowel or urinary bladder. The transrectal route is considered preferable. It is important to remember that such tubes are prone to spontaneous dislodgement, so they are not left in situ for a long time.

Transgluteal approach. Used for draining deep abscesses under CT guidance. The patient is placed in the prone position. To make the procedure least painful and avoid vascular and nerve injury, the trajectory must pass at the level of the sacrospinous ligament (ligamentum sacrospinale), strictly inferior to the piriformis muscle (musculus piriformis), and as close as possible to the sacral bone (os sacrum).

Briefly: answers to topical questions

Class and exam questions

What else to study on this topic

• Features of cone-beam CT (Cone-beam CT) and 3D fusion in interventional radiology.
• Indications for general anesthesia during image-guided interventions in pediatric and uncooperative patients.
• Diagnostics and management tactics for complex psoas abscesses associated with diverticular disease.
• ACR criteria for evaluating the safety of percutaneous splenic interventions.
• Management algorithm for patients with acalculous cholecystitis after drainage tube removal.

Other topics in the "Interventional radiology" section

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