Hepatic abscesses in the immunocompromised patient: role of CT in detection, diagnosis, management, and follow-up

Imaging of hepatic infections

Imaging plays a significant role in the detection, characterization and treatment of hepatic infections. Infectious diseases of the liver include pyogenic and amoebic abscesses and parasitic, fungal, viral and granulomatous infections. With increases in worldwide travel, immunosuppression and changing population demographics, identification of cases of hepatic infection is becoming more common in daily practice. Knowledge of the imaging features seen with hepatic infections can assist in early diagnosis and timely initiation of appropriate therapy. This review presents the imaging appearances of hepatic infections, emphasizing specific features that may contribute to the diagnosis. Examples of the imaging findings seen with pyogenic and amoebic abscesses, infection with Echinococcus granulosus (Hydatid), schistosomiasis, candidiasis and tuberculosis (TB) are presented.

Imaging features of fungal infection in immuno-suppressed patients in a local ward outbreak

Purpose of study

To examine the role of imaging in diagnosing and assessing fungal infections in paediatric patients undergoing chemotherapy in a facility, which had high fungal air contamination due to adjacent building construction work.

Materials and method

Nineteen patients aged five months to 12 years with various malignancies, mainly leukaemia, along with probable fungal infection were referred for imaging over a period of 12 months. The imaging findings from their CT and chest radiographs were reviewed by two radiologists and correlated with the clinical findings. Blood culture and/or biopsy of relevant lesions were performed for all patients.

Results

Fungus was positively isolated in 11 out of 19 patients, but the remaining patients clinically had fungal infection. The most common species isolated was Candida sp. (five patients), followed by Aspergillus sp. The most common site of fungal infection was the lungs (10 out of 19 patients), where consolidation or cavitating nodules were seen on CT or the plain chest radiograph. One patient developed pulmonary artery aneurysm as a complication. The other sites affected were the intra-abdominal organs (liver, kidneys, and spleen) and the paranasal sinuses, shown on CT. Two patients with clinical evidence of infection and Candida sp. isolated from their blood, however, showed no abnormal findings on imaging.

Conclusion

Early diagnosis of fungal infections in oncology patients undergoing chemotherapy is important, but diagnosis may be difficult through imaging because of the non-specific changes and the presence of abnormalities from the underlying disease. Even if a specific diagnosis cannot be reached, imaging is useful to monitor response to treatment and detect complications.

The infected liver: radiologic-pathologic correlation

Recent technologic advances have significantly enhanced the role of imaging in the detection, characterization, and management of infectious diseases involving the liver. In addition, imaging-guided percutaneous drainage has greatly improved the clinical treatment of patients with focal liver abscess. Infectious liver diseases can be accurately evaluated with ultrasonography (US), computed tomography (CT), and magnetic resonance (MR) imaging. Characteristic changes in US echogenicity, CT attenuation, or MR imaging signal intensity and typical enhancement patterns can contribute to the diagnosis of specific infectious diseases, including abscesses, parasitic diseases, fungal diseases, granulomatous diseases, viral hepatitis, and other less common infections. CT is particularly helpful in revealing the presence of calcifications and gas and in detailing the enhancement pattern. The multiplanar capability of MR imaging and its sensitivity to small differences in tissue composition increase its specificity for certain hepatic infections, including hydatid cyst and candidiasis. Radiologic findings may be sufficient to obviate aspiration or histologic examination, although in most instances they are less specific. Nevertheless, imaging findings taken together with appropriate clinical information may provide the most likely diagnosis, even if biopsy is sometimes required for confirmation.

Inflammatory disease of the liver

Imaging and imaging guided intervention have revolutionized the management of hepatic inflammatory diseases. Pyogenic abscess is preferentially treated percutaneously. Radiologic techniques are crucial for the diagnosis of amebic liver abscess and infectious conditions of the liver in immunocompromised patients.

Focal inflammatory diseases of the liver

Inflammatory lesions constitute an important subgroup of focal liver lesions. They may mimic primary or metastatic neoplastic lesions and their differentiation from neoplasia is clinically very important since management of the patient significantly changes. Radiologists should have an important role in both the diagnosis and therapy of these lesions by performing percutaneous aspirations and drainages. In this review we discussed the radiological findings of pyogenic abscesses, amebic abscesses, candidiasis, tuberculosis, hydatic cysts, fascioliasis, ascariasis, schistosomiasis, and sarcoidosis with a special emphasis on US, CT and MR characteristics.

Ultrasound guided percutaneous drainage of abdominal abscesses in the hands of the clinician: a multicenter Italian study

OBJECTIVE

Image guided percutaneous drainage is a well established therapeutic technique. The results of these procedures, when performed directly by the clinician and under sonographic guidance,in respect to other imaging techniques are not yet clarified.

METHODS

The 886 cases of ultrasound guided drainage were collected from eight italian clinical institutions and the results were analyzed according to location of the abscess, drainage technique, underlying diseases, microbiological findings, immunological patient status and previous surgical intervention.

RESULTS

We observed an overall cure rate of 90.4%. The best results were obtained in hepatic abscesses, both amoebic and pyogenic (cure rate 98.7 and 94.3%). Slightly lower cure rates were obtained in abdominal and splenic abscesses, postoperative collections and severely immunocompromised patients. The frequency of complications was low (6.6%) and mostly related to catheter drainage. No drainage-related deaths occurred.

CONCLUSIONS

The study confirms the high clinical efficiency and safety of ultrasound guided percutaneous drainage, even when performed directly by the clinician. The sonographic guidance showed similar efficacy, more manageability and lower costs than other imaging techniques and it should be preferred whenever possible. For hepatic abscesses, ultrasound guided needle aspiration showed good results and less complications than catheter drainage.

Clinical efficacy of ultrasound guided percutaneous drainage of abscesses in patients with leukaemia and lymphoma

Ultrasound guided percutaneous drainage (US-PD), a minimally invasive technique, has been reported as highly effective for the treatment of deeply located abscesses, particularly in immunocompromised patients. Therefore, we retrospectively studied its therapeutic efficacy and safety in a series of 14 patients with leukaemia and lymphoma. We collected the clinical and sonographic data of 14 patients with various types of leukaemia and lymphoma. These patients were consecutively observed in four clinical centres with long-term experience with ultrasound guided therapeutic techniques. The cases were analysed according to underlying disease, clinical features, location of the abscess, drainage technique, microbiological data and both short- and long-term outcome. In our series, 11 patients were treated with repeated ultrasound guided needle aspirations (US-NA) and 3 underwent catheter drainage (US-PCD). In 12/14 cases the procedure was successful (86%): the mortality rate was 14%. 5 patients died during the follow-up period because of the underlying disease, without abscess recurrence. No complications were reported. Our data suggest that ultrasound guided percutaneous drainage should be considered the first choice, minimally invasive procedure for the treatment of deeply located abscesses in patients with leukaemia and lymphoma.

Focal inflammatory disease of the liver

Imaging and image-guided intervention have revolutionized management of hepatic inflammatory diseases. Pyogenic abscess is preferentially treated percutaneously. Radiologic techniques are crucial for the diagnosis of amebic liver abscess and infectious conditions of the liver in immunocompromised patients.

Hepatic abscesses in immunocompromised patients: ultrasonically guided percutaneous drainage

Ultrasonically guided percutaneous drainage (US-PD) is considered first-line therapy for hepatic abscesses, but no data are available on its efficacy in severely immunocompromised patients. Therefore, we examined 15 such patients in whom one or more hepatic abscesses of different etiology were treated with US-PD. Eleven patients underwent needle aspiration and four had catheter drainage under US guidance. In 12 cases we achieved complete healing of the abscesses. In one case, clinical improvement was obtained but surgery was required for cure. In another case (fungal abscess in AIDS), we had no improvement and the patient died. No procedural complications were observed. Seven patients died during the follow-up periods of up to 49 months from their underlying disease. We conclude that US-PD must be considered the therapy of choice for hepatic abscess (except the fungal lesions) in severely immunocompromised patients.