Typical imaging finding of hepatic infections: a pictorial essay

Invasive Klebsiella Syndrome with Liver Abscess and Endogenous Endophthalmitis

Background

Invasive Klebsiella syndrome is an emerging infectious condition that frequently involves pyogenic liver abscess (PLA) and metastatic complications such as endogenous endophthalmitis (EE). This condition is often associated with diabetes mellitus and can result in poor visual prognosis despite treatment.

Case Description

We present the case of a 53-year-old diabetic female who developed EE secondary to a Klebsiella pneumoniae liver abscess. The patient initially presented with fever, fatigue, and abdominal pain, later developing ocular redness and reduced visual acuity. Abdominal ultrasound and computed tomography (CT) confirmed the presence of a multilocular liver abscess. Blood cultures were negative likely due to prior antibiotic use before admission, but Klebsiella pneumoniae was isolated from both the liver abscess and intraocular fluid. She was treated with intravenous (IV) meropenem and metronidazole, along with intravitreal vancomycin and ceftazidime. Despite early percutaneous drainage and antibiotic therapy, the patient's vision did not improve, ultimately requiring evisceration.

Conclusion

This case highlights the importance of early recognition of invasive Klebsiella pneumoniae infections and their metastatic potential. Physicians should consider liver abscess as a possible source of infection in patients presenting with EE. Despite aggressive treatment, the prognosis remains poor, particularly in diabetic patients.

New-onset hepatic lesions in oncological patients: A challenging diagnosis

The appearance of new-onset liver lesions is frequent during imaging follow-up of oncological patients. Most of these lesions will be metastases. But in the presence of atypical radiological findings, there are other diagnoses to consider. Hepatic abscesses, focal nodular hyperplasia-like in patients treated with platinum salts, or hepatocarcinoma in cirrhotic patients are examples of lesions that may appear in the imaging follow-up and should not be confused with metastases. It is essential to establish the nature of the lesion as this will determine the therapeutic management and might avoid unnecessary invasive procedures. The evaluation of previous radiological studies and the global vision of the patient will be primordial. While liver MRI is mainly the indicated imaging technique for these cases, sometimes a biopsy will be unavoidable. In this article, we will discuss through clinical cases some new-onset liver lesions in oncological patients that generated diagnostic doubts and will explain how to orient the diagnosis.

Clinical significance of CA 19-9 elevation during postoperative surveillance for extrahepatic bile duct cancer: a nomogram-based approach for the prediction of short-term recurrence

BACKGROUND

This study aimed to assess the significance of elevated carbohydrate antigen (CA) 19-9 in postoperative surveillance of extrahepatic bile duct cancer and to identify short-term recurrence predictors.

METHODS

This retrospective study included patients with elevated CA 19-9 post-curative surgery. Patients were categorized into positive and negative CT groups based on the detection of recurrence at CA 19-9 elevation. Short-term recurrence was defined as recurrence within 6 months in the negative CT group. We identified the factors associated with short-term recurrence and devised a predictive nomogram.

RESULTS

Among the 190 patients, 91 (47.9 %) exhibited tumor recurrence with CA 19-9 elevation (CT-positive group), whereas 99 (52.1 %) showed no recurrence (CT-negative group). In the CT-negative group (n = 99), 22 (22.2 %) experienced short-term tumor recurrence within 6 months. Preoperative CA 19-9 (odds ratio [OR]: 1.5, p = 0.016), postoperative CA 19-9 (OR: 1.9, p = 0.047), adjuvant treatment (OR: 3.5, p = 0.032), and the absence of inflammation (OR: 3.5, p = 0.045) were predictors of short-term recurrence. The area under the curve of the nomogram was 0.80 (95 % CI: 0.69-0.90).

CONCLUSION

Despite elevated CA 19-9 levels, approximately 50 % of patients exhibited no recurrence during postoperative surveillance for extrahepatic bile duct cancer. Factors influencing short-term recurrence encompass pre- and postoperative CA 19-9, adjuvant treatment, and inflammatory status.

Discontinuous peripheral enhancement of focal liver lesions on CT and MRI: outside the box of typical cavernous hemangioma

The discontinuous peripheral enhancement is a pattern of enhancement usually attributed to typical cavernous hemangioma, that is the most common benign solid lesion of the liver. The discontinuous peripheral enhancement, however, may be encountered in many other benign and malignant focal liver lesions as an atypical presentation or evolution, and hemangiomas with discontinuous peripheral hyperenhancement on hepatic arterial phase may not always have the typical post-contrast pattern on portal venous and delayed phases. Therefore, abdominal radiologists may be challenged in their practice by lesions with discontinuous peripheral enhancement. This pictorial essay aims to review the spectrum of benign and malignant focal liver lesions that may show discontinuous peripheral enhancement. A particular point of interest is the diagnostic tree pathway that may guide the radiologists in the differential diagnosis.

Hepatic cysts: a survival guide

Hepatic cysts are quite common in the daily practice of radiologists and are generally described as simple cysts or as cystic lesions sparsely distributed throughout the parenchyma, often without the discrimination they merit. Simple cysts have, by definition, thin walls, one or two thin septa, and homogeneous fluid content. Such cysts include congenital epithelial cysts, biliary hamartomas, and peribiliary cysts, as well as those representing Caroli's disease or polycystic liver disease. Complex cysts have variable walls, septa, and contents. They also have various etiologies. A detailed assessment of the clinical history and imaging characteristics can assist in making the diagnosis and choosing a course of clinical management. In this review, hepatic cysts are divided, for educational purposes, into five categories: congenital, traumatic, neoplastic, inflammatory, and miscellaneous.

Peribiliary cysts: Two case reports

Peribiliary cysts are an incidental finding in patients with advanced liver disease. They were found to be common in fibrocystic disorders such as autosomal dominant polycystic kidney disease and polycystic liver disease, as well as cirrhotic livers. They result from obstruction-induced cystic dilatation of the peribiliary glands. We report in this article the case of 2 patients, aged 41 and 71, smokers and chronic alcoholics, admitted for febrile cholestatic jaundice, for which MRI revealed the presence of peribiliary cysts.

Echo-intensity characterization at implant sites and novel diagnostic ultrasonographic markers for peri-implantitis

AIM

To apply high-frequency ultrasound (HFUS) echo intensity for characterizing peri-implant tissues at healthy and diseased sites and to investigate the possible ultrasonographic markers of health versus disease.

MATERIALS AND METHODS

Sixty patients presenting 60 implants diagnosed as healthy (N = 30) and peri-implantitis (N = 30) were assessed with HFUS. HFUS scans were imported into a software where first-order greyscale outcomes [i.e., mean echo intensity (EI)] and second-order greyscale outcomes were assessed. Other ultrasonographic outcomes of interest involved the vertical extension of the hypoechoic supracrestal area (HSA), soft-tissue area (STA) and buccal bone dehiscence (BBD), among others.

RESULTS

HFUS EI mean values obtained from peri-implant soft tissue at healthy and diseased sites were 122.9 ± 19.7 and 107.9 ± 24.7 grey levels (GL); p = .02, respectively. All the diseased sites showed the appearance of an HSA that was not present in healthy implants (area under the curve = 1). The proportion of HSA/STA was 37.9% ± 14.8%. Regression analysis showed that EI of the peri-implant soft tissue was significantly different between healthy and peri-implantitis sites (odds ratio 0.97 [95% confidence interval: 0.94-0.99], p = .019).

CONCLUSIONS

HFUS EI characterization of peri-implant tissues shows a significant difference between healthy and diseased sites. HFUS EI and the presence/absence of an HSA may be valid diagnostic ultrasonographic markers to discriminate peri-implant health status.

Computed Tomographic Findings in Dogs with Hepatic Bacterial Parenchymal Infection and Abscessation

Bacterial liver parenchymal infections in dogs are rarely documented, and their imaging characteristics are scarce in the veterinary literature, especially in Computed Tomography (CT). This retrospective multicentric study aimed to describe the CT characteristics of parenchymal bacterial liver infection and abscessation in dogs and compare them with the human literature. Twenty dogs met the inclusion criteria. All dogs, except one, showed discrete hepatic lesions consistent with pyogenic liver abscess (19/20). A single case showed diffuse liver changes, which was diagnosed with granulomatous bacterial hepatitis (1/20). Multifocal lesions were associated with the presence of abdominal pain (p = 0.023). CT characteristics of pyogenic liver abscesses in our study resemble those described in the human literature, with multifocal (14/19) or single (5/19), round or ovoid (19/19), hypoattenuating hepatic lesions, which are better visualised in post-contrast images. Pyogenic liver abscesses can also show features such as the "cluster sign" (8/19), transient arterial segmental enhancement (6/10), rim enhancement (6/19), and intralesional gas (4/19). Additional CT findings, such as local lymphadenomegaly (18/20), peritoneal fat stranding (14/20), and peritoneal fluid (13/20), are also commonly observed.

An exploration of radiological signs in post-intervention liver complications

The advent and progression of radiological techniques in the past few decades have revolutionized the diagnostic and therapeutic landscape for liver diseases. These minimally invasive interventions, ranging from biopsies to complex therapeutic procedures like transjugular intrahepatic portosystemic shunt placement and transarterial embolization, offer substantial benefits for the treatment of patients with liver diseases. They provide accurate tissue diagnosis, allow real-time visualization, and render targeted treatment for hepatic lesions with enhanced precision. Despite their advantages, these procedures are not without risks, with the potential for complications that can significantly impact patient outcomes. It is imperative for radiologists to recognize the signs of these complications promptly to mitigate further health deterioration. Ultrasound, CT, and MRI are widely utilized examinations for monitoring the complications. This article presents an overarching review of the most commonly encountered hepatobiliary complications post-radiological interventions, emphasizing their imaging characteristics to improve patient post-procedure management.

Utility of Contrast-Enhanced Ultrasound in Optimizing Hepatic Abscess Treatment and Monitoring

Background/Objectives: Untreated hepatic abscesses (HAs) have an 80% mortality rate and can be caused by bacteria and fungi. Previously managed with surgery, current treatments now utilize interventional radiology and antibiotics, reducing complications to 2.5%. This study evaluates contrast-enhanced ultrasound (CEUS) for better drainage placement and monitoring, overcoming conventional ultrasound's limitations in detecting the HA liquefied portion. Methods: We conducted a retrospective study of 50 patients with HAs confirmed via computed tomography (CT) scans. Inclusion criteria comprised specific clinical symptoms and laboratory parameters. Both B-mode and CEUS were utilized for initial and follow-up imaging. Results: In the CEUS studies, the mean size of HAs was 6.26 cm, with pus displaying significantly lower echogenicity compared to the HA pouch and liver parenchyma in all phases. Classification by size (>6 cm, <6 cm) and volume (>113 mL, <113 mL) revealed differences in the assessment of fluid volume between CEUS and B-mode. Conclusions: CEUS is valuable for diagnosing, performing therapeutic procedures, and monitoring HA. It provides precise real-time assessment of HA morphology, including dimensions and volume. If the liquefied volume of an HA exceeds 113 mL, it may qualify for drainage placement. CEUS can replace CT as an effective, less harmful, and cheaper method, eliminating the need for multiple radiological departments. While CEUS is a safer, cost-effective alternative to CT for HA evaluation and monitoring, comprehensive clinical evaluation remains essential. Therefore, CEUS should be part of a broader diagnostic and monitoring strategy, not a stand-alone solution.

Benign and malignant focal liver lesions displaying rim arterial phase hyperenhancement on CT and MRI

Rim arterial phase hyperenhancement is an imaging feature commonly encountered on contrast-enhanced CT and MRI in focal liver lesions. Rim arterial phase hyperenhancement is a subtype of arterial phase hyperenhancement mainly present at the periphery of lesions on the arterial phase. It is caused by a relative arterialization of the periphery compared with the center of the lesion and needs to be differentiated from other patterns of peripheral enhancement, including the peripheral discontinuous nodular enhancement and the corona enhancement. Rim arterial phase hyperenhancement may be a typical or an atypical imaging presentation of many benign and malignant focal liver lesions, challenging the radiologists during imaging interpretation. Benign focal liver lesions that may show rim arterial phase hyperenhancement may have a vascular, infectious, or inflammatory origin. Malignant focal liver lesions displaying rim arterial phase hyperenhancement may have a vascular, hepatocellular, biliary, lymphoid, or secondary origin. The differences in imaging characteristics on contrast-enhanced CT may be subtle, and a multiparametric approach on MRI may be helpful to narrow the list of differentials. This article aims to review the broad spectrum of focal liver lesions that may show rim arterial phase hyperenhancement, using an approach based on the benign and malignant nature of lesions and their histologic origin. CRITICAL RELEVANCE STATEMENT: Rim arterial phase hyperenhancement may be an imaging feature encountered in benign and malignant focal liver lesions and the diagnostic algorithm approach provided in this educational review may guide toward the final diagnosis. KEY POINTS: Several focal liver lesions may demonstrate rim arterial phase hyperenhancement. Rim arterial phase hyperenhancement may occur in vascular, inflammatory, and neoplastic lesions. Rim arterial phase hyperenhancement may challenge radiologists during image interpretation.

Imaging of abdominopelvic oncologic emergencies

With advancements in cancer treatment, the survival rates for many malignancies have increased. However, both the primary tumors and the treatments themselves can give rise to various complications. Acute symptoms in oncology patients require prompt attention. Abdominopelvic oncologic emergencies can be classified into four distinct categories: vascular, bowel, hepatopancreatobiliary, and bone-related complications. Radiologists need to be familiar with these complications to ensure timely diagnosis, which ultimately enhances patient outcomes.

Epidemiology, Clinical Characteristics and Risk Factors for Severity of Chronic Disseminated Candidiasis in Jerusalem, Israel

Chronic disseminated candidiasis (CDC) occurs mostly in patients with acute hematologic malignancy and its clinical manifestations derive from immune reconstitution following neutrophil recovery. The aim of this study was to describe epidemiological and clinical characteristics of CDC and define risk factors for disease severity. Demographic and clinical data were collected from medical files of patients with CDC hospitalized in two tertiary medical centers in Jerusalem between 2005 and 2020. Associations between different variables and disease severity were evaluated, as well as characterization of Candida species. The study included 35 patients. CDC incidence slightly increased during study years and the average number of involved organs and disease duration was 3 ± 1.26 and 178 ± 123 days, respectively. Candida grew in blood in less than third of cases and the most common isolated pathogen was Candida tropicalis (50%). Histopathological or microbiological workup in patients who underwent an organ biopsy demonstrated Candida in about half of the patients. Nine months after starting antifungals, 43% of the patients still didn't have resolution of organ lesions in imaging modalities. Factors associated with protracted and extensive disease were prolonged fever prior to CDC and absence of candidemia. A C- Reactive Protein (CRP) cutoff level of 7.18 mg/dL was found to predict extensive disease. In conclusion, CDC incidence is increasing and the number of involved organs is higher than previously described. Clinical factors such as fever duration prior to CDC and absence of candidemia can predict severe course of disease and assist in treatment decisions and follow-up planning.

Complications after Thermal Ablation of Hepatocellular Carcinoma and Liver Metastases: Imaging Findings

Tumour ablation is a strategy of treatment of hepatic tumours in patients with small hepatocellular carcinoma (HCC) (<3 cm) or in patients unfit for surgical resection. Moreover, tumor ablation can be used as an adjuvant therapy or may be used in association with resection in case of patients with poor functional liver disease. These types of treatment usually could be performed percutaneously under image guidance. The most clinically verified and used ablation modalities are Radiofrequency Ablation (RFA) and microwave ablation (MWA). However, despite both of them are considered minimally invasive techniques, they could be related to post-procedural complications. The International Working Group on Image-Guided Tumor and the Society of Interventional Radiology (SIR) identified major and minor post-ablative complications. Major complications, as vascular complications, occur in 2.2% to 3.1% of cases and include all the high risk pathological conditions which could increase the level of care or result in hospital admission or substantially prolonged hospital stay (SIR classifications C−E). Minor complications, as biliary complications, occur in 5% to 8.9% and include self-limiting conditions that are considered to be of low risk for the patient’s outcome. The purpose of this review is to summarise the main pathological ultrasound (US) and Computed Tomography (CT) findings, that may arise after ablative treatment. To simplify the analysis, the pathological pictures are divided according to the site of damage into vascular, biliary and extrahepatic complications.

Sonographic Detection of Hepatic Abscesses

Hepatic abscesses are masses or lesions within the liver as a response to an infection manifesting into the liver. Hepatic abscess can be a result of other abdominal diseases, such as any biliary tract disease or appendicitis. Because of its inconsistent characteristics in many imaging modalities, its appearance can be mistaken for other pathologies like liver metastasis. With the use of one or more imaging modalities and an imaging-guided biopsy of the targeted lesion, hepatic abscess can be confirmed. The case presents multiple hepatic abscesses throughout the liver with similar imaging characteristics as that of metastasis. Computed tomography (CT), sonography, magnetic resonance imaging, and a biopsy were performed to successfully diagnose the hepatic abscesses.

Beyond the Liver Function Tests: A Radiologist's Guide to the Liver Blood Tests

Liver blood tests (often also known as liver chemistries, liver tests, or the common misnomer liver function tests) are routinely used in diagnosis and management of hepatobiliary disease. Abnormal liver blood test results are often the first indicator of hepatobiliary disease and a common indication for abdominal imaging with US, CT, or MRI. Most of the disease entities can be categorized into hepatocellular or cholestatic patterns, with characteristic traits on liver blood tests. Each pattern has a specific differential, which can help narrow the differential diagnosis when combined with the clinical history and imaging findings. This article reviews the major liver blood tests as well as a general approach to recognizing common patterns of hepatobiliary disease within these tests (hepatocellular, cholestatic, acute liver failure, isolated hyperbilirubinemia). Examples of hepatobiliary disease with hepatocellular or cholestatic patterns are presented with characteristic test abnormalities and imaging findings. The commonly encountered scenario of chronic hepatitis with possible fibrosis is also reviewed, with discussion of potential further imaging such as elastography. The role of liver blood tests and imaging in evaluating complications of hepatic transplant is also discussed. Overall, integrating liver blood test patterns with imaging findings can help the radiologist accurately diagnose hepatobiliary disease, especially in cases where imaging findings may not allow differentiation between different entities. ^©RSNA, 2021.