CT of small pyogenic hepatic abscesses: the cluster sign

Clostridium difficile Bacteremia as a Rare Presentation of Polymicrobial Pyogenic Liver Abscesses and Its Management Challenges

Extracolonic manifestations of Clostridium difficile have been rarely reported. We herein report a case of a 60-year-old immunocompetent man presenting with fever, nausea, abdominal pain, and loose stools for 2 weeks. Triple-phase liver computed tomography demonstrated pyogenic liver abscesses and portal pylephlebitis. Blood cultures grew C. difficile and Bacteroides fragilis, and liver abscess cultures grew Proteus mirabilis, Escherichia coli, and the viridans group Streptococci. Antibiotics coverage was selected to direct at all identified organisms. This demonstrates an unusual case of C. difficile bacteremia in a patient with polymicrobial pyogenic liver abscesses and pylephlebitis.

Transjugular intrahepatic portosystemic shunt (TIPS) complications: what diagnostic radiologists should know

Transjugular intrahepatic portosystemic shunt (TIPS) is an effective therapy for portal hypertension complications and can successfully treat variceal bleeding and refractory ascites. Although TIPS is relatively safe, procedural- or shunt-related morbidity can reach 20%, and procedural complications have a fatality rate of 2%. Delayed recognition and treatment of TIPS complications can lead to life-threatening clinical scenarios. Complications can vary from stent migration or malpositioning to nontarget organ injury, TIPS dysfunction, encephalopathy, or liver failure. This review aims to outline the role of diagnostic radiology in assessing post-TIPS complications.

Differentiation of Small Hepatic Abscess From Hepatic Metastasis With a Combination of Imaging Parameters

OBJECTIVE

We aimed to evaluate the diagnostic performance of the combination imaging features to differentiate small (the lesion size of 3 cm or less) hepatic abscess from metastasis.

METHODS

This retrospective study included patients with preexisting malignancy and small hepatic lesions who underwent contrast-enhanced computed tomography (CT) and gadoxetic acid-enhanced magnetic resonance imaging (MRI) within 4 days between March 2017 and July 2020. Two radiologists independently evaluated the imaging features of each focal hepatic lesion. Laboratory parameters were also recorded. Significant parameters differentiating hepatic abscess from hepatic metastasis were identified by univariate generalized estimating equation regression. We compared the diagnostic performances of laboratory parameters, imaging features, and their combinations.

RESULTS

We included 16 patients (10 males and 6 females) with 35 hepatic abscesses and 21 patients (13 males and 8 females) with 62 metastases with a mean age of 70.3 years in this study. Abnormal segmental neutrophil, pathy parenchymal enhancement on CT, and absence of dark rim on MRI were associated with hepatic abscess (all P < 0.01). The combination of CT and MRI parameters showed significantly higher specificity and positive predictive value than CT alone (P ≤ 0.031), without significant difference in sensitivity and negative predictive value.

CONCLUSIONS

We have demonstrated that the combination of CT and MRI imaging features is helpful for the differentiation of small hepatic abscess from metastasis.

Imaging Spectrum of Intrahepatic Mass-Forming Cholangiocarcinoma and Its Mimickers: How to Differentiate Them Using MRI

Intrahepatic cholangiocarcinoma (ICC) is the second most common primary hepatic malignancy, with mass-forming growth pattern being the most common. The typical imaging appearance of mass-forming ICC (mICC) consists of irregular ring enhancement in the arterial phase followed by the progressive central enhancement on portal venous and delayed phases. However, atypical imaging presentation in the form of hypervascular mICC might also be seen, which can be attributed to distinct pathological characteristics. Ancillary imaging features such as lobular shape, capsular retraction, segmental biliary dilatation, and vascular encasement favor the diagnosis of mICC. Nevertheless, these radiological findings may also be present in certain benign conditions such as focal confluent fibrosis, sclerosing hemangioma, organizing hepatic abscess, or the pseudosolid form of hydatid disease. In addition, a few malignant lesions including primary liver lymphoma, hemangioendothelioma, solitary hypovascular liver metastases, and atypical forms of hepatocellular carcinoma (HCC), such as scirrhous HCC, infiltrative HCC, and poorly differentiated HCC, may also pose a diagnostic dilemma by simulating mICC in imaging studies. Diffusion-weighted imaging and the use of hepatobiliary contrast agents might be helpful for differential diagnosis in certain cases. The aim of this manuscript is to provide a comprehensive overview of mICC imaging features and to describe useful tips for differential diagnosis with its potential mimickers.

Differentiating Between an Atypical Hepatic Abscess and Tumor Metastasis Using Magnetic Resonance Imaging and Hepatobiliary Phase Imaging

Objective

To identify diffusion-weighted imaging (DWI) patterns and conspicuity discrepancies on hepatobiliary phase imaging (HBPI) to distinguish atypical hepatic abscesses from hepatic metastases.

Materials and Methods

This retrospective study recruited 31 patients with 43 atypical hepatic abscesses and 32 patients with 35 hepatic metastases who underwent gadobenate dimeglumine-enhanced magnetic resonance imaging. All lesions were confirmed by pathological or clinical diagnosis. For the qualitative and quantitative analyses, the signal intensity, DWI pattern, apparent diffusion coefficient, degree of perilesional edema, perilesional hyperemia, perilesional signal on HBPI, conspicuity, size discrepancy between sequences, contrast-to-noise ratio, signal-to-noise ratio, and relative enhancement ratio on dynamic phases were independently assessed by two radiologists. Significant findings for differentiating the two groups were identified via univariate and multivariate analyses with a nomogram for predicting atypical hepatic abscesses. The interobserver agreement was also analyzed for each variable.

Results

The multivariate analysis revealed that the conspicuity discrepancy (odds ratio [OR] 34.78, 95% confidence interval [CI] 2.09–579.47, p = 0.013) and non-peripheral high signal intensity (SI) rim on DWI (OR 67.46, 95% CI 2.64, 1723.20, p = 0.011) were significant independent factors for predicting atypical hepatic abscesses. They were also shown to be high predictor points on the nomogram. When any of the set criteria were satisfied, 97.7% of atypical hepatic abscesses were correctly identified, with a specificity of 65.7%. When both criteria were combined, the specificity was up to 100%, with a sensitivity of 44.9%.

Conclusion

Conspicuity discrepancy and a non-peripheral high SI rim on DWI are reliable and meaningful features that can distinguish atypical hepatic abscesses from hepatic metastases.

Typical imaging finding of hepatic infections: a pictorial essay

Hepatic infections are frequent in clinical practice. Although epidemiological, clinical and laboratory data may suggest hepatic infection in certain cases, imaging is nearly always necessary to confirm the diagnosis, assess disease extension and its complications, evaluate the response to treatment, and sometimes to make differential diagnoses such as malignancies. Ultrasound (US) is usually the first-line investigation, while computed tomography (CT) and magnetic resonance imaging (MRI) provide better characterization and a more precise assessment of local extension, especially biliary and vascular. The purpose of this article is to describe the typical features and main complications of common hepatic infections. Familiarity with the radiological features of this entity can help suggest the correct diagnosis and the need for further studies as well as determine appropriate and timely treatment.

Multiple Pyogenic Liver Abscesses Mimicking Metastatic Disease on Computed Tomography

Liver abscesses are divided into two main subgroups: pyogenic and nonpyogenic abscesses. Early diagnosis is important for appropriate treatment and to reduce the morbidity and mortality rates in liver abscesses. We report a case of multiple pyogenic liver abscesses mimicking liver metastases on multidetector computed tomography (MDCT). The case is unique as it shows a rare presentation of pyogenic liver abscess that cannot be distinguished from metastatic liver disease. Microbiologic and pathologic correlations with follow-up may be necessary for these patients. The case is presented with an emphasis on the MDCT findings.

Beyond pyogenic liver abscess: a comprehensive review of liver infections in emergency settings

Hepatobiliary infections are commonly encountered in emergency settings ranging from common pathology such as pyogenic abscess to relatively uncommon and rare etiologies. Since extensive literature is already available on imaging of more common bacterial infections, for the sake of focused discussion, this review will discuss radiological appearance of less commonly encountered hepatic infections of fungal, parasitic, viral, and tubercular etiologies. Epidemiological and clinical information remain extremely important for obtaining more accurate presumptive diagnosis. In the era of diverse population migration, a modern-era radiologist must be well versed about the imaging spectrum of liver infections.

Differentiation of hepatic abscess from metastasis on contrast-enhanced dynamic computed tomography in patients with a history of extrahepatic malignancy: emphasis on dynamic change of arterial rim enhancement

OBJECTIVES

The objective of the study is to identify computed tomography (CT) findings that differentiate hepatic abscess from hepatic metastasis in a patient with a history of extrahepatic malignancy.

MATERIALS AND METHODS

This retrospective study included 30 patients with 93 hepatic abscesses and 40 patients with 125 hepatic metastases who had a history of extrahepatic malignancy and underwent contrast-enhanced dynamic CT with arterial phase (AP) and portal venous phase (PVP). The diagnosis of hepatic abscess and hepatic metastasis was made using pathological confirmation or clinical diagnosis. Margin, patchy parenchymal enhancement, arterial rim enhancement, dynamic change of arterial rim enhancement, size discrepancy of lesions between arterial and portal phases, bile duct dilatation, perilesional hyperemia, and perilesional low density were evaluated by two radiologists independently. Significant findings for differentiating two groups were identified at univariate and multivariate analysis with nomogram for predicting hepatic abscess. Interobserver agreement was also analyzed for each variable.

RESULTS

Multivariate analysis revealed that patchy parenchymal enhancement (P < 0.001), arterial rim enhancement persistent through PVP (P < 0.001), and perilesional hyperemia (P = 0.013) were independent significant findings to predict hepatic abscess than metastasis. Among them, arterial rim enhancement persistent through PVP showed a highest odds ratio (OR 33.73) on multivariate analysis and a highest predictor point on a nomogram for predicting hepatic abscess. When two of these three criteria were combined, 80.7% (75/93) of hepatic abscess were correctly identified, with a specificity of 85.6% (107/125). When all three criteria were satisfied, specificity was up to 100% (125/125).

CONCLUSIONS

At contrast-enhanced dynamic CT, patchy parenchymal enhancement, arterial rim enhancement persistent through PVP, perilesional hyperemia, and their combinations may be reliable CT features for differentiating hepatic abscess from metastasis in patients with a history of primary extrahepatic malignancy.

Hepatocellular carcinoma disguised as liver abscesses

The incidence of hepatocellular carcinoma (HCC) is growing rapidly in the United States. Nonalcoholic fatty liver disease and nonalcoholic steatohepatitis are being increasingly recognized as known risk factors for the development of HCC. However, this risk seems to be associated with their progression to cirrhosis. This case demonstrates an unusual initial presentation of HCC masquerading as liver abscesses in a previously healthy woman with nonalcoholic fatty liver disease without cirrhosis. Our patient's clinical presentation was suspicious for an infectious etiology due to her ongoing fever in the setting of possible zoonotic transmission, because she had just acquired two unvaccinated kittens. Abscess-like clinical presentation can be seen in HCC and is due to neoplasm-associated granulocytosis. Fever is due to pyrogen production by malignant tumor cells or by macrophages. Therefore, HCC can be difficult to differentiate from a hepatic abscess, and aspiration of malignant cells may be needed for an accurate diagnosis. Although the incidence of HCC in nonalcoholic fatty liver disease without cirrhosis is low or unknown, surveillance for HCC should be considered due to the higher prevalence of nonalcoholic fatty liver disease in the developed world and its potential risk for HCC.

Transient Segmental Enhancement of Pyogenic Liver Abscess: A Comparison Between Contrast-Enhanced Ultrasound and Computed Tomography

OBJECTIVE

This study aimed to investigate the correlation between the transient segmental enhancement (TSE) of liver abscesses on contrast-enhanced ultrasound (CEUS) imaging and contrast-enhanced computed tomography (CT) scans.

METHODS

In total, 42 abscesses in 38 patients were evaluated with real-time CEUS and contrast-enhanced CT imaging. The CT imaging and CEUS examinations were performed within one to 2 days of each other in all cases. The initial reports of the observations of TSE on CEUS scans were correlated later with the findings of TSE on contrast-enhanced CT images. Contrast-enhanced CT was used as the reference standard to evaluate the presence of TSE. Relationships between the 2 groups were analyzed using the χ test. P < 0.05 was considered to be statistically significant.

RESULTS

In 16 patients, 16 typical TSE signs were shown by CEUS. Meanwhile, enhanced CT imaging showed 18 typical signs of TSE in 17 patients. We identified 38 patients with hepatic abscesses proven by needle aspiration (10 patients) or image-guided biopsy (28 patients). Ten patients had hepatobiliary cholelithiasis, 5 had diabetes mellitus type 2, and 2 had gastric cancer, whereas no evidence of underlying hepatobiliary or gastrointestinal diseases was found in the other 21 patients. Considering that enhanced CT is the reference standard for the diagnosis of hepatic abscesses, the sensitivity of CEUS in showing TSE was 89%, and the specificity was 100%. The χ test indicated that CEUS and enhanced CT were significantly correlated for detection of hepatic perfusion disorders (P < 0.05).

CONCLUSIONS

The appearance of TSE in liver abscess was reliably detected by CEUS, which correlated well with the enhanced CT images (P < 0.05).

Beyond the Bowel: Extraintestinal Manifestations of Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a chronic, relapsing immune-mediated inflammation of the gastrointestinal tract. IBD includes two major disease entities: Crohn disease and ulcerative colitis. Imaging plays an important role in the diagnosis and surveillance of these complex disorders. Computed tomographic and magnetic resonance enterographic techniques have been refined in recent years to provide a superb means of evaluating the gastrointestinal tract for suspected IBD. Although the intestinal imaging manifestations of IBD have been extensively discussed in the radiology literature, extraintestinal imaging manifestations of IBD have received less attention. Multiple extraintestinal manifestations may be seen in IBD, including those of gastrointestinal (hepatobiliary and pancreatic), genitourinary, musculoskeletal, pulmonary, cardiac, ocular, and dermatologic disorders. Although many associations between IBD and extraintestinal organ systems have been well established, other associations have not been fully elucidated. Some extraintestinal disorders may share a common pathogenesis with IBD. Other extraintestinal disorders may occur as a result of unintended treatment-related complications of IBD. Although extraintestinal disorders within the abdomen and pelvis may be well depicted with cross-sectional enterography, other musculoskeletal and thoracic disorders may be less evident with such examinations and may warrant further investigation with additional imaging examinations or may be readily apparent from the findings at physical examination. Radiologists involved in the interpretation of IBD imaging examinations must be aware of potential extraintestinal manifestations, to provide referring clinicians with an accurate and comprehensive profile of patients with these complex disorders. ^© RSNA, 2017.

Differentiation of small intrahepatic mass-forming cholangiocarcinoma from small liver abscess by dual source dual-energy CT quantitative parameters

PURPOSE

To investigate the use of dual source dual-energy CT (DECT) quantitative parameters compared with the use of conventional CT for differentiating small (≤3cm) intrahepatic mass-forming cholangiocarcinoma (IMCC) from small liver abscess (LA) during the portal venous phase (PVP).

MATERIAL AND METHODS

In this institutional review board-approved, retrospective study, 64 patients with IMCCs and 52 patients with LAs who were imaged in PVP using dual-energy mode were included retrospectively. A radiologist drew circular regions of interest in the lesion on the virtual monochromatic images (VMI), color-coded iodine overlay images, and linear blending images with a linear blending ratio of 0.3 to obtain CT value, its standard deviation, slope (k) of spectral curve and normalized iodine concentration (NIC). Two radiologists assessed lesion type on the basis of qualitative CT imaging features.

RESULTS

CT values on VMI at 50-130keV (20keV-interval), k, and NIC values were significantly higher in IMCCs than in LAs (p<0.0001). The best single parameter for differentiating IMCC from LA was CT value at 90keV, with sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of 89.1%, 86.5%, 87.9%, 89.1%, and 86.5%, respectively. The best combination of parameters was CT value at 90keV, k, and NIC, with values of 87.5%, 84.6%, 83.6%, 87.5%, and 84.6%, respectively. Compared with CT value at linear blending images, CT value at 90keV showed greater sensitivity (89.1% vs 60.9%, p<0.0001) and similar specificity (86.5% vs 84.6%, p=1.0000), and combined CT value at 90keV, k, and NIC showed greater sensitivity (87.5% vs 60.9%, p<0.0001) and similar specificity (84.6% vs 84.6%, p=1.0000). Compared with qualitative analysis, CT value at 90keV showed greater sensitivity (89.1% vs 65.6%, p=0.0059) and specificity (86.5% vs 69.2%, p=0.0352), and combined CT value at 90keV, k, and NIC showed greater sensitivity (87.5% vs 65.6%, p=0.0094) and similar specificity (84.6% vs 69.2%, p >0.05).

CONCLUSION

Quantitative analysis of dual source dual-energy CT quantitative parameters showed greater accuracy than quantitative and qualitative analyses of conventional CT for differentiating small IMCCs from small LAs on single PVP scan.

The value of gadoxetic acid-enhanced MRI for differentiation between hepatic microabscesses and metastases in patients with periampullary cancer

OBJECTIVES

We aimed to identify features that differentiate hepatic microabscess from hepatic metastasis on gadoxetic acid-enhanced MRI in patients with periampullary cancer.

METHODS

We included 72 patients (31 patients with 83 hepatic microabscesses and 41 patients with 71 hepatic metastases) who had a history of periampullary cancer and underwent gadoxetic acid-enhanced MRI. Image analysis was performed for margin, signal intensity, rim enhancement, perilesional hyperaemia, pattern on DWI and dynamic phases, and size discrepancy between sequences by consensus of two observers.

RESULTS

Multivariate analysis revealed that the following significant parameters favour microabscess: a history of bile duct cancer, perilesional hyperaemia, persistent arterial rim enhancement through the transitional phase (TP), and size discrepancy between T1WI and T2WI and between T1WI and hepatobiliary phase image (HBPI). The diagnostic accuracy for microabscess was highest (90.9%) when showing a size discrepancy ≥30% between T1WI and HBPI or persistent arterial rim enhancement through the TP. When the lesion was positive for both these variables, specificity reached 100%.

CONCLUSION

The combination of a size discrepancy between T1WI and HBPI and persistent arterial rim enhancement through the TP represents a reliable MRI feature for distinguishing between hepatic microabscess and metastasis in patients with periampullary cancer.

KEY POINTS

• Gadoxetic acid-enhanced MRI is useful for distinguishing hepatic microabscess from metastasis. • Hepatic microabscess showed significant size discrepancy ≥30% between T1WI and HBPI. • Arterial rim enhancement persistent through the TP indicates hepatic microabscess.

A Rare Case of Fusobacterium Necrophorum Liver Abscesses

Liver abscesses are an uncommon disease that can present with vague symptoms. Fusobacterium necrophorum causing liver abscesses is a rare condition and only a few cases have been reported. An 88-year-old female presented to her primary care physician with one week of fevers, night sweats, chills, fatigue and vague right upper quadrant abdominal pain. She denied nausea, vomiting, constipation, diarrhea and unintentional weight loss. A computed tomography scan of the abdomen showed two liver abscesses in the right lobe as well as extensive diverticulosis. Percutaneous drainage was performed and draining catheters were placed in the abscesses. Culture of the abscess fluid grew Fusobacterium necrophorum. She was treated with ceftriaxone and metronidazole as per sensitivities. Rare cases of F. necrophorum hepatic abscesses have been published. The source of infection described in reported cases included hematogenous spread from dental caries/peritonsillar abscess and those involving the gastrointestinal tract resulting from inflammation of the bowel wall or from inflamed diverticuli via the portal circulation. In one study, thirteen cases of liver abscess due to F. necrophorum were studied, and two of these cases had diverticular disease without inflammation.

Multimodality Imaging of Liver Infections: Differential Diagnosis and Potential Pitfalls

Imaging plays an important role in the diagnosis, characterization, and management of infectious liver disease. In clinical practice, the main contributions of imaging are in detecting early disease, excluding other entities with a similar presentation, establishing a definitive diagnosis when classic findings are present, and guiding appropriate antimicrobial, interventional, or surgical treatment. The most common imaging features of bacterial, viral, parasitic, and fungal hepatic infections are described, and key imaging and clinical manifestations are reviewed that may be useful to narrow the differential diagnosis and avoid pitfalls in image interpretation. Ultrasonography (US), computed tomography (CT), and magnetic resonance imaging allow accurate detection of most hepatic infections and, in some circumstances, may provide specific signs to identify the underlying pathogen and exclude other entities with similar imaging features. In bacterial and parasitic infections, specific imaging features may be enough to exclude a neoplasm and, occasionally, to identify the underlying infectious agent. US and CT are important means to guide percutaneous aspiration or drainage when needed. In viral infections, imaging is critical to exclude entities that may manifest with similar clinical and laboratory findings. Disseminated fungal infections require early detection at imaging because they can be fatal if not promptly treated. Familiarity with the epidemiology, pathogenesis, clinical manifestations, imaging features, and treatment of hepatic infections can aid in radiologic diagnosis and guide appropriate patient care. (©)RSNA, 2016.

Contrast-enhanced ultrasound in different stages of pyogenic liver abscess

To enable sonographic classification of different stages of pyogenic liver abscesses, sonographic findings in 86 patients with 113 pyogenic liver abscesses were retrospectively analyzed and compared with established pathomorphologic descriptions of the disease. The typical findings in contrast-enhanced ultrasound were sub-segmental hyperemia (93/113, 82%) and necrosis with a hyperemic margin (109/113, 96%) in the arterial phase and a washout of liver tissue surrounding necrosis in the late phase (101/113, 89%). Four different sonomorphologic stages of pyogenic liver abscess were identified. Stage I was defined by focal inflammation without necrosis (n = 2); stage II by focal clusters of micro-abscesses appearing to coalesce (n = 41); and stage III by a single cavity with or without capsule (n = 64). Stage IV was defined as numerous small abscesses scattered all over the liver (n = 6). The results indicate that contrast-enhanced ultrasound is suitable for classifying different stages of pyogenic liver abscesses. Knowledge of the described morphologic patterns influences therapeutic decisions and helps distinguish abscesses from other liver masses.

Spectrum of multilocular cystic hepatic lesions: CT and MR imaging findings with pathologic correlation

A multilocular cystic hepatic lesion detected at computed tomography (CT) and magnetic resonance (MR) imaging is a common but nonspecific radiologic finding that can cause potential challenges for differential diagnosis. This imaging pattern may be observed in a wide spectrum of common and uncommon neoplastic or nonneoplastic entities. Neoplastic lesions include cystadenoma, cystadenocarcinoma, hepatocellular carcinoma (HCC), metastases, mesenchymal hamartoma, and inflammatory myofibroblastic tumor. Nonneoplastic lesions include hepatic abscess, echinococcal cyst, intrahepatic hematoma, and biloma. The multiple coalescent cysts seen in polycystic liver disease may exhibit an imaging pattern similar to that of a multilocular cystic lesion. Mural nodularity, irregular thickness of the septa, ragged inner surface, and typical enhancement pattern in the solid portion of the lesion are often indicative of malignancy, although multilocular primary or secondary malignant tumors are uncommon. Recognition of the more common necrosis or cystic change of HCC and metastases induced by locoregional or systemic treatment also is important. The nonenhanced cystic component may be composed of different types of fluids (eg, serous, mucinous, proteinaceous, hemorrhagic, bilious, or mixed) or spontaneous or treatment-related necrosis, whereas the septa may be formed by a wide range of tissues depending on the lesion type. An understanding of the CT and MR imaging findings of these lesions and their respective pathologic correlation aids in accurate diagnosis.

MR imaging of benign focal liver lesions

Focal liver lesions (FLLs) are commonly encountered on routine imaging studies. Most lesions detected are benign, but many are indeterminate at the time of initial imaging. This article reviews the important role of MR imaging for the detection and characterization of various benign FLLs while illustrating typical imaging appearances and potential pitfalls in interpretation. The utility of diffusion-weighted imaging and hepatocyte-specific contrast agents is also discussed.

Emphysematous hepatitis--a fatal infection in diabetic patients: case report

Emphysematous hepatitis is a rare fatal rapidly progressive fulminant infection of hepatic parenchyma seen in the setting of diabetes characterised by replacement of hepatic parenchyma with gas collection. There is paucity of literature with regard to pathogenesis, implicated organisms, imaging appearance and management of this condition. We report a case with extensive segmental replacement of liver parenchyma with gas. The fatality of this condition warrants awareness of this entity amongst radiologists and clinicians alike for early diagnosis and aggressive management.

Malignant versus benign hepatic masses in patients with recurrent pyogenic cholangitis: MR differential diagnosis

PURPOSE

To assess MR findings and diagnostic performance for differentiating malignant from benign hepatic masses in recurrent pyogenic cholangitis (RPC).

MATERIALS AND METHODS

During a recent 6-year period, we performed MRI in 352 patients with RPC. Among them, 58 had confirmed hepatic masses; cholangiocarcinoma (n = 15), abscess (n = 37), inflammatory pseudotumor (n = 3), biloma (n = 3). Two radiologists assessed MR findings including enhancement patterns, intratumoral appearance, peritumoral changes, mass location, and multiplicity. They also graded the malignancy using common MR findings. The receiver operating characteristic analysis and Chi-square test were used. The κ statistics was used to determine interobserver agreement.

RESULTS

The common findings for cholangiocarcinoma were thin and lobulated enhancement at the periphery (n = 8, 53%, P < 0.05); ill-defined enhancement (n = 7, 47%, P < 0.05); slightly high signal on T2 (n = 13, 87%, P < 0.05); mass located in the same lobe of atrophy (n = 11, 73%, P < 0.05) and portal vein thrombosis (n = 15, 100%, P < 0.05). The common findings for benign mass were target-like enhancement (n = 36, 84%, P < 0.05); cluster appearance (n = 15, 35%, P < 0.05); central, fluid-like space (n = 29, 67%, P < 0.05); peritumoral regional high signal on T2 (n = 32, 74%, P < 0.05); multiplicity(n = 21, 49%, P < 0.05). Interobserver agreement was excellent (κ = 0.81-1.000). Area under the curve (Az) for differentiating malignant masses was 0.989, sensitivity was 95.3%, and specificity was 95.3%. There was good interobserver agreement (κ = 0.74).

CONCLUSION

MR imaging is very useful for differential diagnosis of malignant vs. benign hepatic masses in patients with RPC.

Factors associated with treatment failure of percutaneous catheter drainage for pyogenic liver abscess in patients with hepatobiliary-pancreatic cancer

BACKGROUND

The aim of this study was to identify predictors of treatment failure of percutaneous catheter drainage (PCD) in patients with hepatobiliary-pancreatic cancer with pyogenic liver abscess (PLA).

METHODS

Medical records of 44 patients with PLA with underlying hepatobiliary-pancreatic cancer who underwent PCD under computed tomographic guidance as primary treatment between January 2001 and December 2010 were collected and reviewed. Included patients were diagnosed with cholangiocarcinoma (n = 16), hepatocellular carcinoma (n = 12), pancreatic carcinoma (n = 9), carcinoma of the ampulla of Vater (n = 6), and gallbladder cancer (n = 1). The clinical factors related to failure of PCD were determined using logistic regression.

RESULTS

The median age of the 44 patients with PLA was 68 years, and 48% were men. PCD failed in 15 patients (34%). Of the 15 patients with PCD failure, 12 subsequently required surgical intervention because of either clinical deterioration or imaging that demonstrated failure of abscess resolution with PCD. Three of these patients died with the initial drain in place before resolution of the abscess. In patients requiring surgery after PCD failure, the frequency of cure or abscess resolution reached 67%. Fourteen patients (32%) died during hospitalization. Multivariate analysis identified that multiloculated abscesses (P = .005) and abscesses with biliary communication (P = .036) were associated with failure of PCD.

CONCLUSIONS

Multiloculated abscesses and lesions with biliary communication pose a greater likelihood of failure of PCD in patients with hepatobiliary-pancreatic cancer with PLA. Early surgical intervention after PCD failure should be considered for these patients.

Hepatic abscesses

Hepatic abscesses are potentially lethal diseases if early diagnosis and treatment are not instituted. They are prevalent all over the globe and pyogenic abscesses are predominant over amoebic. With better control of intra abdominal and systemic infections by a spectrum of antibiotics, aetiology of pyogenic abscesses are secondary to interventions and diseases in the biliary tree to a large extent today. The common organisms isolated are the Gram negative group. Amoebic abscesses continue to plague some regions of the world where hygiene and sanitation are questionable. Over the years, diagnosis, treatment and prognosis have evolved remarkably. Imaging modalities like ultrasonography and CT scan have become the cornerstone of diagnosis. The absence of ionizing radiation makes MRI an attractive alternative in patients who require multiple follow up scans. Serological testing in amoebic abscesses has become more reliable. Though antibiotics have remained the principal modality of management, percutaneous drainage of abscesses have vastly improved the chances of cure and bring down the morbidity drastically in pyogenic abscesses. Amoebic abscesses respond well to medical treatment with nitroimidazoles, and minimally invasive surgical drainage is an option in cases where open surgery is indicated.

A case of emphysematous hepatitis with spontaneous pneumoperitoneum in a patient with hilar cholangiocarcinoma

An 80-year-old woman with hilar cholangiocarcinoma was hospitalized due to sudden-onset abdominal pain. Computed tomography revealed hepatic necrosis accompanied with emphysematous change in the superior segment of the right liver (S7/S8), implying spontaneous rupture, based on the presence of perihepatic free air. Although urgent percutaneous drainage was performed, neither pus nor fluids were drained. These findings suggest emphysematous hepatitis with a hepatic mass. Despite the application of intensive care, the patient's condition deteriorated rapidly, and she died 3 days after admission to hospital. Liver gas has been reported in some clinical diseases (e.g., liver abscess) to be caused by gas-forming organisms; however, emphysematous hepatitis simulating emphysematous pyelonephritis is very rare. The case reported here was of fatal emphysematous hepatitis in a patient with hilar cholangiocarcinoma.

Pseudo-tumoral hepatic tuberculosis discovered after surgical resection

Pseudo-tumoral hepatic tuberculosis is rare. It is characterized by non-specific symptoms and radiological polymorphism. Diagnosis is problematic. This article presents three cases, each clinically different from each other, that illustrate how difficult diagnosis can be. The definitive diagnosis of pseudo-tumoral hepatic tuberculosis was reached on the basis of histo-logical examination of surgical samples. Treatment of the disease based on appropriate anti-tubercular therapy generally gives a positive outcome.

Clinical outcomes and prognostic factors of cancer patients with pyogenic liver abscess

PURPOSE

Pyogenic liver abscess (PLA) of cancer patients often has a poor prognosis, but corresponding prognostic factors are less investigated. This study aimed to identify predictors of mortality in cancer patients with PLA.

PATIENTS AND METHODS

Medical records of 85 consecutive cancer patients (46 with hepatobiliary pancreatic cancer, 14 with gastrointestinal cancer, and 25 with non-digestive system cancer) having PLA who were admitted to two university hospitals were retrospectively reviewed. The predictors of mortality were determined using Cox regression model.

RESULTS

The overall case fatality rate was 33%. In multivariate analysis, the greater Acute Physiology and Chronic Health Evaluation II score (P = 0.028), multiloculated abscess (P = 0.025), and polymicrobial infection (P = 0.003) were associated with mortality. In subgroup analysis of the 25 patients with multiloculated abscess undergoing percutaneous catheter drainage as primary treatment, the case fatality rates of patients with a solitary smaller abscess (size < 5 cm), those with a solitary larger abscess (size > 5 cm), and those with larger multiple abscesses were 0%, 36%, and 85%, respectively (P = 0.002; using χ (2) for trend).

CONCLUSIONS

The advanced disease stage, multiloculated abscess, and polymicrobial infection posed a greater mortality risk in cancer patients with PLA. Moreover, an early surgical approach should be considered for cancer patients having large, multiloculated complex PLAs.

Correlations between MDCT features and clinicopathological findings of hepatic paragonimiasis

AIM

To illustrate the MDCT features of hepatic paragonimiasis and correlate the results with clinicopathological findings.

MATERIALS AND METHODS

Eighteen patients (8 male, 10 female; mean age 37years) with hepatic paragonimiasis were included in this study. MDCT features of their hepatic lesions were retrospectively reviewed and correlated with clinicopathological findings.

RESULTS

All patients were lifelong residents in endemic areas of paragonimiasis, especially Paragonimiasis skrjabini variety. Abdominal pain or discomfort, fever and high eosinophil percentage were the predominant clinical features. In total, 21 lesions were detected on MDCT images, 18 (85.7%) directly contacted the hepatic capsule and 3 (14.3%) were adjacent to the capsule. Segment V (26%), VIII (26%) and VI (18.5%) were the most commonly involved sites. Sixteen lesions (76%) were conglomerated cystic or multilocular and 5 (24%) were solid. On plain MDCT scan, the margin and internal detail of the lesions were not clear except for one cystic variety, while they were clearly demonstrated on enhanced images. Single or multiple cysts with different diameters were commonly detected in the non-solid lesions, and some of them were mutually connected with tortuous tract formation. Among the solid lesions, 2 and 3 showed tubular and homogeneous enhancement, respectively.

CONCLUSION

Peripherally distributed lesions, mutually connected cysts with tortuous tract formation, and tubular enhancement, which may be closely associated with the infection route and migration of the worm, could be seen as the main MDCT features of hepatic paragonimiasis.

Upper abdominal ultrasound in the critically ill

Intraabdominal pathology, either primary or secondary, may frequently be found in critically ill patients. Without early diagnosis and treatment, the patient's condition may deteriorate and even progress to death. In this article, we provide a current review of the literature regarding liver, biliary, pancreatic, and splenic problems in critically ill patients and describe common ultrasound findings, including the appearance of free intraperitoneal air. According to the liver surface, edge, echotexture, and echogenicity, either diffuse liver diseases or focal liver diseases can be detected on ultrasound. By scanning the biliary tree and gallbladder, many right upper quadrant diseases can be diagnosed. The role of ultrasound for acute pancreatic pathology is to identify any lesions and to evaluate the severity of the diseases. Similarly, the spleen can be evaluated for relevant pathology in the critical care setting.

Computed tomographic differences of pyogenic liver abscesses caused by Klebsiella pneumoniae and non-Klebsiella pneumoniae

OBJECTIVE

To investigate the distinctive computed tomographic(CT) features of pyogenic liver abscess (PLA) caused by Klebsiella pneumoniae (KLA).

METHODS

114 PLA patients (62 men, 52 women, age range 25-89 years, mean age 60.9 years) with positive yield of blood or pus cultures were divided into 2 groups; KLA group (n = 58) and non-KLA group (n = 56). We retrospectively reviewed the CT images. The independent-sample t-test, X2 test, or Fisher's exact test were used with SPSS for windows version 11.0.

RESULTS

Gas formation showed no significant difference between two groups (P = 0.284), but air-fluid pattern was found only in KLA group (P = 0.027). The rim on dynamic CT was showed less frequently in KLA group than non-KLA group (P < 0.001), and smooth and regular rim was more common in non-KLA group (P < 0.001). The septation and septal breakage were more common in KLA group (P < 0.001). The turquoise sign was found significantly more in KLA group (P < 0.001). The hairball sign was detected only in KLA group (P < 0.001). The cluster sign was less frequent in KLA group (P < 0.001).

CONCLUSION

KLA had a series of characteristic intra-abscess features; septal breakage, turquoise-like structure, hairball-like content, air-fluid level, and no enhanced rim. When turquoise/hairball sign or air-fluid level is present in abscess, KLA would be a probable diagnosis in the clinical field.

CT appearance of Varicella Zoster lesions in liver and spleen in an immunocompetent patient

An adult patient presented with vesicular rash and abdominal pain of 5 days duration. His initial laboratory results showed elevated liver enzymes. A contrast enhanced CT scan demonstrated multiple small hypodense nodules in liver and spleen. His serum was reactive for Varicella Zoster IgM. Patient was treated with intravenous Acyclovir for 5 days and followed up with oral tablets for 2 weeks. At 3 weeks, CT scan showed resolution of hypodense nodules and his serum liver enzymes returned to normal at 6 weeks. Patient is on follow up and asymptomatic for 2 years. The CT appearances of nodules and their resolution following specific antiviral therapy are useful in diagnosis and in follow up of disseminated Varicella Zoster.

Solid Organizing Hepatic Abscesses Mimic Hepatic Tumor

OBJECTIVE

To describe the computed tomography (CT) and magnetic resonance imaging (MRI) findings of solid organizing hepatic abscesses and correlate them with the pathologic findings.

METHODS

Ten patients with 10 pathologically proven solid organizing hepatic abscesses who underwent 3-phase CT (n = 10) or MRI (n = 7) were enrolled in this study. Images were retrospectively analyzed by consensus of 2 radiologists for attenuation (signal intensity), shape, and margin of the lesions as well as for their enhancement patterns. Their imaging findings were correlated with their pathologic findings.

RESULTS

The main imaging finding on CT or MRI was the well-defined target appearance of a central enhancing area with a low-attenuation (signal intensity) rim on arterial and portal phases. On the delayed phase, most of lesions showed slightly low attenuation (signal intensity) with an enhancing rim, and 1 showed diffuse enhancement. Pathologically, the central areas and peripheral rims corresponded to granulation tissue and fibrosis, respectively. Nine lesions demonstrated a tiny necrotic cystic portion in the center.

CONCLUSION

The target appearance of solid organizing hepatic abscesses on CT and MRI can be helpful in differentiating them from other focal liver lesions. These imaging findings are well correlated with the pathologic findings.

Fulminant infection with emphysematous changes in the biliary tract and air-filled liver abscesses

Gas-producing infections are related to anaerobic bacteria and usually associated with immunosuppressive pathologies such as diabetes and have a fulminating course. We present the clinical course of a patient with diabetes whose infection progressed rapidly and ended in her dramatic death in a short period; surgical therapy was impossible, and the disease behaved similarly to type I emphysematous pyelonephritis.

Multidetector Row CT of the Liver

CT has always played a major role in the imaging of the liver despite continuous challenge by ultrasound and MR imaging. Introduction of multidetector row CT technology has helped CT to excel in its already established indications and has expanded its capabilities by adding new clinical indications, such as CT angiography or liver perfusion. This article discusses the advantages of multidetector row CT scanners in liver imaging, examines the guidelines to improve image quality by optimizing scanning protocols and contrast administration strategies, and reviews the current and potential clinical applications.

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.

Imaging diagnosis of 12 patients with hepatic tuberculosis

AIM

To assess CT, MR manifestations and their diagnostic value in hepatic tuberculosis.

METHODS

CT findings in 12 cases and MR findings in 4 cases of hepatic tuberculosis proved by surgery or biopsy were retrospectively analyzed.

RESULTS

(1) CT findings: One case of serohepatic type of hepatic tuberculosis had multiple-nodular lesions in the subcapsule of liver. Parenchymal type was found in 10 cases, including multiple, miliary, micronodular and low-density lesions with miliary calcifications in 2 cases; singular, low-density mass with multiple flecked calcifications in 3 cases; multiple cystic lesions in 1 case; multiple micronodular and low-density lesions fusing into multiloculated cystic mass or "cluster" sign in 3 cases; and singular, macronodular and low-density lesion with multiple miliary calcifications in 1 case. One case of tuberculous cholangitis showed marked dilated intrahepatic ducts with multiple flecked calcifications in the porta hepatis. (2) MR findings in 4 cases were hypointense on both T1-weighted imagings and T2-weighted imagings in one case, hypointense on T1-weighted imagings and hyperintense on T2-weighted imagings in 3 cases. Enhanced MR in 3 cases was slightly shown peripheral enhancement or with multilocular enhancement.

CONCLUSION

Various types of hepatic tuberculosis have different imaging findings, and typical CT and MR findings can suggest the diagnosis.

Pyogenic hepatic abscesses: distinctive features from hypovascular hepatic malignancies on contrast-enhanced ultrasound with SH U 508A; early experience

The aim of this study was to investigate the feasibility of contrast-enhanced US (conE US) in differentiating pyogenic hepatic abscesses (PyHAs) from hypovascular hepatic malignancies. conE US images of 16 PyHAs in 12 patients were evaluated retrospectively and were compared with those of 22 hypovascular hepatic malignancies in 12 patients. The conE US images were obtained at 30, 90, 150 and 270 s after a bolus injection of 4 g of SH U 508A (Levovist, Schering; 300 mg/mL). The images were specifically analyzed for the shape (round or ovoid, lobulating or coalescent according to the complexity), the margin (sharp or ill-defined), and the pattern of contrast agent enhancement of the lesion (internal and rim enhancement). In our experience, as to the shape of the lesion, PyHAs were usually coalescent (94%), and hepatic malignancies were more frequently round or ovoid (36%) or lobulating (50%) (p < 0.0001). The margin of the lesion was usually sharp in PyHAs (81%), whereas it was more commonly ill-defined (59%) in hepatic malignancies (p = 0.02). Whereas PYHAs usually produced no internal enhancement (94%), diffuse (73%) or peripheral (27%) hypoechoic intratumoral enhancement was seen in hepatic malignancies (p < 0.0001). This study shows that conE US is potentially useful in differentiation of PyHAs from hypovascular hepatic malignancies. PyHAs usually produce characteristic features, such as coalescent appearance, sharp boundary of necrotic cavity, and lack of internal enhancement on conE US.

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Imaging in haematopoietic stem cell transplantation

Haematopoietic stem cell transplantation (SCT) is used to treat a wide range of malignant and non-malignant haematological conditions, solid malignancies, and metabolic and autoimmune diseases. Although imaging has a limited role before SCT, it is important after transplantation when it may support the clinical diagnosis of a variety of complications. It may also be used to monitor the effect of therapy and to detect recurrence of the underlying disease if the transplant is unsuccessful. We present a pictorial review of the imaging of patients who have undergone SCT, based upon 15 years experience in a large unit performing both adult and paediatric transplants.

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.

MR imaging of infective liver lesions

This article discusses MR imaging of infective liver lesions including pyogenic liver abscesses, amebic liver abscesses, echinococcal disease, hepatic fungal abscesses, granulomatous hepatic infections, schistosomiasis, and fascioliasis.

Imaging the patient with right upper quadrant pain

A variety of high-resolution imaging techniques are currently available for the evaluation of patients with RUQ pain. In these patients, an imaging approach that is based on identifying the presence of certain clinical signs and symptoms can aid in choosing the appropriate imaging modality and establishing the diagnosis. For patients presenting with a positive Murphy sign, sonography and biliary scintigraphy are the most useful initial imaging techniques. In patients with fever and a negative Murphy sign, a combination of sonography and contrast-enhanced CT can establish the diagnosis in most cases. And finally, in patients without fever or a positive Murphy sign, CT and MR are appropriate first-line imaging techniques.

Dynamic CT of hepatic abscesses: significance of transient segmental enhancement

OBJECTIVE

The purpose of this study was to evaluate dynamic CT findings of hepatic abscesses, especially segmental hepatic enhancement, and to clarify the cause.

MATERIALS AND METHODS

Twenty-four abscesses in eight patients were examined by early (30 sec) and late phase (90 sec) dynamic CT. Patients underwent abscess drainage (n = 1), hepatic resection (n = 2), or antibiotic therapy (n = 5). CT during arterial portography and CT during hepatic arteriography were performed in one patient. We retrospectively observed the frequency and changes of segmental hepatic enhancement on dynamic CT and determined its cause using radiologic and pathologic correlation.

RESULTS

Sixteen abscesses (67%) showed transient segmental hepatic enhancement and three abscesses showed only segmental hepatic enhancement in the early phase. Four abscesses in one patient who underwent CT during arterial portography and CT during hepatic arteriography showed a segmental perfusion defect on CT during arterial portography and segmental enhancement on CT during hepatic arteriography. On follow-up dynamic CT performed 10-17 days after the initial CT, segmental hepatic enhancement surrounding hepatic abscesses decreased or disappeared in all abscesses. Pathologic examination of two patients showed marked inflammatory cell infiltration with stenosis of portal venules within the portal tracts surrounding hepatic abscesses without definite inflammation in the liver parenchyma.

CONCLUSION

Segmental hepatic enhancement on dynamic CT is frequently associated with hepatic abscesses and may be caused by decreased portal flow resulting from inflammation of the portal tracts.

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.