Cystic lesions of the liver. AJR Am J Roentgenol. 2011;196:W355-W366. [PMID: 21427297 DOI: 10.2214/ajr.10.5292]

Surgical and oncologic outcomes for liver resections of cystic neuroendocrine tumor liver metastasis

BACKGROUND

Cystic neuroendocrine tumor liver metastases (NETLM) are rare and dynamics in the liquid compartment often misinterpreted as rapid progression, affecting selection for liver resection candidates. This study retrospectively evaluates surgical and oncologic outcomes in patients with cystic versus solid NETLM from small bowel and pancreatic primaries.

METHODS

Between 2000 and 2020, 12 patients with cystic NETLM were identified among 464 patients who underwent >90 % tumor cytoreduction debulking hepatectomy at the Mayo Clinic. Tumor and patient characteristics, as well as surgical and oncologic outcomes, were compared with the total cohort of patients with solid NETLM, including a propensity-matched cohort.

RESULTS

Patients with cystic NETLM were similar in age (55.4 vs. 59.7 years; p = 0.113) and sex (58 % vs. 51 % men; p = 0.772) to those with solid NETLM. Synchronous metastases (92 % vs. 77 %; p = 0.314), bilobar distribution (83 % vs. 79 %; p = 1.000), lesion numbers (p = 0.547), Ki67 % expression (p = 0.311), and extrahepatic lesions (8 % vs. 18 %; p = 0.702) were similar. Cystic metastases were larger (7.3 vs. 3.8 cm; p < 0.001). Surgical risk did not differ, with major morbidity (25 % vs. 22 %; p = 0.729) and mortality (0 % vs. <2 %; p = 1.000). Median overall survival (OS) was 13.8 vs. 10.6 years (p = 0.513), and hepatic-progression-free survival (PFS) was 0.71 vs. 1.78 years (p = 0.507). Matched cohorts showed no significant difference in OS (13.80 vs. 8.57; p = 0.316) or hepatic-PFS (0.71 vs. 1.33; p = 0.620).

CONCLUSION

Surgical risk and long-term outcomes do not significantly differ between cystic and solid NETLMs. Given excellent long-term survival rates with >90 % cytoreduction, radical debulking is advised for both phenotypes when clinically feasible.

Massive Hepatomegaly in a Pediatric Patient Due to a Solitary Simple Hepatic Cyst: A Case Report

This case report presents a six-year-old male patient with massive hepatomegaly attributed to a solitary simple hepatic cyst. The patient was referred to the pediatric gastroenterology clinic after his family noted progressive abdominal distention over four months, with no associated symptoms such as pain, jaundice, or systemic illness. Physical examination revealed significant hepatomegaly and initial laboratory investigations indicated mild transaminitis but were otherwise unremarkable. Imaging with abdominal ultrasound demonstrated a single large cystic lesion, which was further characterized by computed tomography (CT) as a 12-cm simple hepatic cyst. The differential diagnosis included conditions such as polycystic liver disease and hydatid disease, but these were ruled out based on clinical presentation and imaging findings. Given the benign nature of the cyst and the absence of symptoms, conservative management was pursued, with regular follow-up to monitor for potential complications. The patient remained asymptomatic during a six-month follow-up, highlighting the importance of individualized monitoring and management in cases of pediatric hepatic cysts. This case contributes to the understanding of simple hepatic cysts in children and underscores the need for careful diagnostic evaluation and long-term follow-up.

Imaging features and management of focal liver lesions

Notably, the number of incidentally detected focal liver lesions (FLLs) has increased dramatically in recent years due to the increased use of radiological imaging. The diagnosis of FLLs can be made through a well-documented medical history, physical examination, laboratory tests, and appropriate imaging methods. Although benign FLLs are more common than malignant ones in adults, even in patients with primary malignancy, accurate diagnosis of incidental FLLs is of utmost clinical significance. In clinical practice, FLLs are frequently evaluated non-invasively using ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MRI). Although US is a cost-effective and widely used imaging method, its diagnostic specificity and sensitivity for FLL characterization are limited. FLLs are primarily characterized by obtaining enhancement patterns through dynamic contrast-enhanced CT and MRI. MRI is a problem-solving method with high specificity and sensitivity, commonly used for the evaluation of FLLs that cannot be characterized by US or CT. Recent technical advancements in MRI, along with the use of hepatobiliary-specific MRI contrast agents, have significantly improved the success of FLL characterization and reduced unnecessary biopsies. The American College of Radiology (ACR) appropriateness criteria are evidence-based recommendations intended to assist clinicians in selecting the optimal imaging or treatment option for their patients. ACR Appropriateness Criteria Liver Lesion-Initial Characterization guideline provides recommendations for the imaging methods that should be used for the characterization of incidentally detected FLLs in various clinical scenarios. The American College of Gastroenterology (ACG) Clinical Guideline offers evidence-based recommendations for both the diagnosis and management of FLL. American Association for the Study of Liver Diseases (AASLD) Practice Guidance provides an approach to the diagnosis and management of patients with hepatocellular carcinoma. In this article, FLLs are reviewed with a comprehensive analysis of ACR Appropriateness Criteria, ACG Clinical Guideline, AASLD Practice Guidance, and current medical literature from peer-reviewed journals. The article includes a discussion of imaging methods used for the assessment of FLL, current recommended imaging techniques, innovations in liver imaging, contrast agents, imaging features of common nonmetastatic benign and malignant FLL, as well as current management recommendations.

Spatial Coherence Approaches to Distinguish Suspicious Mass Contents in Fundamental and Harmonic Breast Ultrasound Images

When compared to fundamental B-mode imaging, coherence-based beamforming, and harmonic imaging are independently known to reduce acoustic clutter, distinguish solid from fluid content in indeterminate breast masses, and thereby reduce unnecessary biopsies during a breast cancer diagnosis. However, a systematic investigation of independent and combined coherence beamforming and harmonic imaging approaches is necessary for the clinical deployment of the most optimal approach. Therefore, we compare the performance of fundamental and harmonic images created with short-lag spatial coherence (SLSC), M-weighted SLSC (M-SLSC), SLSC combined with robust principal component analysis with no M-weighting (r-SLSC), and r-SLSC with M-weighting (R-SLSC), relative to traditional fundamental and harmonic B-mode images, when distinguishing solid from fluid breast masses. Raw channel data acquired from 40 total breast masses (28 solid, 7 fluid, 5 mixed) were beamformed and analyzed. The contrast of fluid masses was better with fundamental rather than harmonic coherence imaging, due to the lower spatial coherence within the fluid masses in the fundamental coherence images. Relative to SLSC imaging, M-SLSC, r-SLSC, and R-SLSC imaging provided similar contrast across multiple masses (with the exception of clinically challenging complicated cysts) and minimized the range of generalized contrast-to-noise ratios (gCNRs) of fluid masses, yet required additional computational resources. Among the eight coherence imaging modes compared, fundamental SLSC imaging best identified fluid versus solid breast mass contents, outperforming fundamental and harmonic B-mode imaging. With fundamental SLSC images, the specificity and sensitivity to identify fluid masses using the reader-independent metrics of contrast difference, mean lag one coherence (LOC), and gCNR were 0.86 and 1, 1 and 0.89, and 1 and 1, respectively. Results demonstrate that fundamental SLSC imaging and gCNR (or LOC if no coherence image or background region of interest is introduced) have the greatest potential to impact clinical decisions and improve the diagnostic certainty of breast mass contents. These observations are additionally anticipated to extend to masses in other organs.

External validation of a machine learning based algorithm to differentiate hepatic mucinous cystic neoplasms from benign hepatic cysts

PURPOSE

To externally validate an algorithm for non-invasive differentiation of hepatic mucinous cystic neoplasms (MCN) from benign hepatic cysts (BHC), which differ in management.

METHODS

Patients with cystic liver lesions pathologically confirmed as MCN or BHC between January 2005 and March 2022 from multiple institutions were retrospectively included. Five readers (2 radiologists, 3 non-radiologist physicians) independently reviewed contrast-enhanced CT or MRI examinations before tissue sampling and applied the 3-feature classification algorithm described by Hardie et al. to differentiate between MCN and BHC, which had a reported accuracy of 93.5%. The classification was then compared to the pathology results. Interreader agreement between readers across different levels of experience was evaluated with Fleiss' Kappa.

RESULTS

The final cohort included 159 patients, median age of 62 years (IQR [52.0, 70.0]), 66.7% female (106). Of all patients, 89.3% (142) had BHC, and the remaining 10.7% (17) had MCN on pathology. Agreement for class designation between the radiologists was almost perfect (Fleiss' Kappa 0.840, p < 0.001). The algorithm had an accuracy of 98.1% (95% CI [94.6%, 99.6%]), a positive predictive value of 100.0% (95% CI [76.8%, 100.0%]), a negative predictive value of 97.9% (95% CI [94.1%, 99.6%]), and an area under the receiver operator characteristic curve (AUC) of 0.911 (95% CI [0.818, 1.000]).

CONCLUSION

The evaluated algorithm showed similarly high diagnostic accuracy in our external, multi-institutional validation cohort. This 3-feature algorithm is easily and rapidly applied and its features are reproducible among radiologists, showing promise as a clinical decision support tool.

Cytology as the guiding light: Prompt cytomorphologic diagnosis of cystic metastases from a jejunal neuroendocrine tumor masquerading as hepatic abscesses

Hepatic cystic lesions are commonly seen in radiology and can occur due to infective or neoplastic causes. It is imperative to determine the precise nature of these hepatic cysts owing to significant therapeutic and prognostic differences. Hepatic metastases from gastrointestinal neuroendocrine tumors (NETs) mostly present as solid hypervascular lesions. Cystic presentation of the metastatic NETs is extremely rare. A 64-year-old woman presented with an abdominal lump of 3 months duration and high-grade fever from the last 2 days. An ultrasound abdomen revealed multiple hypoechoic liver lesions suggestive of liver abscesses. An ultrasound-guided fine-needle aspiration (FNA) from the cystic liver lesions revealed a NET confirmed by immunocytochemistry. The Ki-67 index was 5%; hence, a final diagnosis of metastatic NET, grade 2, was given with advice to work up for localizing the primary tumor. Subsequently, a contrast-enhanced computerized tomography of the abdomen revealed a polypoidal lesion in the proximal jejunum, which showed intense expression on the whole-body DOTANOC scan (SUVmax-76.5), indicating it to be the likely primary tumor along with somatostatin receptor-expressing multiple lymph nodes and hypodense liver lesions. Thus, a final diagnosis of a jejunal NET with abdominal lymph node and liver metastases was made. The present report highlights the importance of FNA as a reliable modality in diagnosing metastatic NETs presenting as unusual cystic hepatic metastases masquerading as liver abscesses. Additionally, the cell block helps confirm the cytologic diagnosis and enables upfront tumor grading, thereby helping in prognostication and therapeutic decision-making.

Primary hepatic myopericytoma coexisting with multiple cystic hepatic lesions: a case report

BACKGROUND

Hepatic myopericytoma (MPC) is an extremely rare pathological entity in the liver. Conversely, cystic hepatic lesions are a group of heterogeneous lesions encountered commonly in daily practice. Here, we report a unique case of the coexistence of primary hepatic MPC and multiple cystic hepatic lesions along with our perceptions on its diagnosis and treatment.

CASE PRESENTATION

A 56-year-old female patient was found to have a left liver mass during a routine physical examination. Computer tomography (CT) and magnetic resonance imaging (MRI) confirmed the existence of a left hepatic neoplasm along with multiple hepatic cysts but could not exclude the possible malignant nature of the neoplasm. Computer tomography (CT) also identified an enlarged mediastinal lymph node with a maximum diameter of 4.3 cm, which further underwent core needle biopsy under CT guidance. A histopathological examination was performed to rule out malignancy. Afterwards, the patient underwent left hemihepatectomy to resect a solid tumor of 5.5 cm × 5 cm × 4.7 cm with multiple cystic lesions which were histopathologically examined to establish the diagnosis of myopericytoma with hepatic cysts. Postoperatively, the patient recovered from the surgery quickly without significant adverse events and was not found to have a reoccurrence of the primary pathological entity.

CONCLUSIONS

This is the first reported case of a patient with the co-existence of primary hepatic myopericytoma and multiple cystic hepatic lesions undergoing surgical treatment with eventual recovery.

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.

Case report: Rare isolated cystic hepatic metastasis of a patient with squamous cell lung carcinoma history and the prognosis

Cystic hepatic metastasis of squamous cell carcinoma usually develops from necrosis due to insufficient blood supply, yet metastasis initially resembling simple liver cyst is rare. Here, we present a case of a patient with squamous cell lung carcinoma history who found an isolated cystic mass in the liver. Historical MR studies indicated that the mass did not exist 12 months ago and emerged as a small cystic lesion 7 months ago. Radiological findings and tumor markers level suggested metastasis, while 18F-Fluorodeoxyglucose (18F-FDG) PET/CT showed moderate tracer uptakes in solid parts of the mass. Pathological study after surgery confirmed metastatic squamous cell carcinoma. Chemotherapy plus recombinant human endostatin and sintilimab therapy was employed after surgery; however, the patient developed remote metastasis of osteolytic lesions in the humerus bone and thoracic vertebra. Our case indicates that metastasis should be taken into consideration in emerging cystic hepatic lesion with malignant history.

Polycystic Liver Disease: Pathophysiology, Diagnosis and Treatment

Polycystic liver disease (PLD) is a clinical condition characterized by the presence of more than 10 cysts in the liver. It is a rare disease Of genetic etiology that presents as an isolated disease or assoc\iated with polycystic kidney disease. Ductal plate malformation, ciliary dysfunction, and changes in cell signaling are the main factors involved in its pathogenesis. Most patients with PLD are asymptomatic, but in 2-5% of cases the disease has disabling symptoms and a significant reduction in quality of life. The diagnosis is based on family history of hepatic and/or renal polycystic disease, clinical manifestations, patient age, and polycystic liver phenotype shown on imaging examinations. PLD treatment has evolved considerably in the last decades. Somatostatin analogues hold promise in controlling disease progression, but liver transplantation remains a unique curative treatment modality.

“Starry liver” - Von Meyenburg complex clinical case presentation and differential diagnosis discussion: A case report

BACKGROUND

Von Meyenburg complex (VMC) (i.e., biliary hamartoma) is a rare congenital disorder characterized by multiple dilated cystic bile ducts, without clear trends in sex or age predominance. Due to the low number of published cases and the lack of recognized guidelines, the management of such patients remains a clinical challenge.

CASE SUMMARY

We present a case of symptomatic VMC that was diagnosed after imaging and histopathological examinations. Considering the patient’s condition, a conservative treatment strategy was chosen. Instrumental, laboratory, and clinical follow-up demonstrated the stable condition of the patient receiving conservative treatment.

CONCLUSION

VMC is a potentially non-life threatening condition, but its recognition is crucial for the management of patients.

Focal incidental upper abdominal findings on unenhanced chest computed tomography that do not require further imaging: a roadmap for the thoracic radiologist

Abstract Chest scans usually include the upper abdomen, leading radiologists to evaluate the upper abdominal structures. The aim of this article is to summarize the most common incidental upper abdominal findings that do not require further imaging or management in patients undergoing unenhanced computed tomography of the chest for the investigation of thoracic symptoms or diseases. We review common incidental findings of the liver, gallbladder, spleen, adrenal glands, kidney, and retroperitoneum, as well as findings that mimic other lesions. Thoracic radiologists should be aware of such typical findings and report when no further investigation is needed, thus avoiding unnecessary imaging examinations, protecting patients from additional medical interventions, and allaying patient concerns.

[Incidental and "leave me alone" findings of abdominal organs-part 1 : Liver, gall ducts and pancreas]

Incidentalomas of the parenchymal organs of the abdomen, i.e. radiological findings in these organs that are not the primary focus of the clinical question, are frequent in this region of the body. In particular, findings presumed to be unimportant, such as cystic masses in the liver, the bile duct system or the pancreas, initially appear to be irrelevant in the diagnosis. For the liver we define the mostly clearly diagnosable simple cysts and hemangiomas as leave me alone lesions. Otherwise, we recommend a classification of incidentalomas into the three major categories (<0.5 cm, 0.5-1.5 cm and >1.5 cm) as well as an assessment with respect to clearly benign and suspect imaging characteristics in the context of a classification of patients into three different risk groups.

Deletion of kif3a in CK19 positive cells leads to primary cilia loss, biliary cell proliferation and cystic liver lesions in TAA-treated mice

BACKGROUND & AIMS

Loss of primary cilia in epithelial cells is known to cause cystic diseases of the liver and kidney. We have previously shown that during experimental and human cirrhosis that primary cilia were predominantly expressed on biliary cells in the ductular reaction. However, the role of primary cilia in the pathogenesis of the ductular reaction is not fully understood.

METHODS

Primary cilia were specifically removed in biliary epithelial cells (BECs) by the administration of tamoxifen to Kif3a^f/f;CK19^CreERT mice at week 2 of a 20-week course of TAA treatment. Biliary progenitor cells were isolated and grown as organoids from gallbladders. Cells and tissue were analysed using histology, immunohistochemistry and Western blot assays.

RESULTS

At the end of 20 weeks TAA administration, primary cilia loss in liver BECs resulted in multiple microscopic cystic lesions within an unaltered ductular reaction. These were not seen in control mice who did not receive TAA. There was no effect of biliary primary cilia loss on the development of cirrhosis. Increased cellular proliferation was seen within the cystic structures associated with a decrease in hepatocyte lobular proliferation. Loss of primary cilia within biliary organoids was initially associated with reduced cell passage survival but this inhibitory effect was diminished in later passages. ERK but not WNT signalling was enhanced in primary cilia loss-induced cystic lesions in vivo and its inhibition reduced the expansion of primary cilia deficient biliary progenitor cells in vitro.

CONCLUSIONS

TAA-treated kif3a BEC-specific knockout mice had an unaltered progression to cirrhosis, but developed cystic lesions that showed increased proliferation.

Case Report: Robotically Assisted Excision of Cystic Tumor Located in a Difficult to Access Area in the Liver

Introduction: Cystic liver lesions may be benign cysts, parasitic infestations, or malignant tumors requiring surgical resection. Hilar location and relation to major vasculature present challenges in conventional surgical access and resection. Materials and Methods: We describe totally robotic excision of a cystadenoma in a 55-year-old woman without complication. Time points in the accompanying video (https://youtu.be/Tn_QPgpSHA4) are embedded within the text. Results: Advantages of the robotic technique lie in overcoming the natural restriction of conventional laparoscopic instruments, easier repair, and control of intraoperative vascular injuries using EndoWrist^® instruments, ergonomic dissection close to major vasculature and reduced intraoperative blood loss as dissection is easier. Discussion: Indications for robotic surgery included the large size of the cystic lesion, its intrahepatic location, and compression of the inferior vena cava (IVC) and right and middle hepatic veins. Had robotic removal of the lesion not been feasible, the entire lobe of the liver would have required resection.

Giant haemorrhagic hepatic cyst with flame-like morphology in a patient with polycystic kidney and liver disease

Introduction

Intracystic haemorrhage is a rare complication of hepatic cysts, and is often mistaken for a malignant lesion.

Case Report

A 55-year-old female with a history of polycystic kidney and liver disease presented with a six-month history of abdominal distension, abdominal pain, early satiety, shortness of breath and 5 kg of weight loss. Imaging revealed a 20 cm mixed solid-cystic hepatic lesion containing peripheral avascular mobile echogenic material with a flame-like morphology. After experiencing symptomatic relief from ultrasound-guided aspiration, the patient underwent cyst fenestration for more definitive treatment.

Discussion

Haemorrhagic hepatic cysts are uncommon and may present on imaging as having lace-like retractile clot, internal layering or shading of separating blood products or avascular mobile flame-like excrescences. The presence of avascular mobile flame-like excrescences appears to be a unique feature of haemorrhagic hepatic cysts.

Conclusion

While haemorrhagic hepatic cysts are rare and commonly mistaken for biliary cystadenomas or adenocarcinomas, the identification of particular features on high-resolution magnetic resonance imaging and contrast-enhanced ultrasound can lead to the correct diagnosis.

Incidental Liver Findings on Cross-sectional Imaging

Hepatic incidental findings often are seen on cross-sectional imaging examinations of the chest, spine, pelvis, or other nondedicated hepatic imaging. Radiologists are tasked with appropriately triaging, which requires further evaluation, even in the setting of an otherwise limited evaluation. This article reviews common benign entities encountered on ultrasound, computed tomography, or magnetic resonance imaging, along with their characteristic imaging features. Imaging features that are suspicious for malignancy or suggest the need for further evaluation also are discussed. Two algorithms are proposed to guide radiologists in their recommendations based on patient risk factors, focal hepatic abnormality size, and available imaging features.

Long-term outcome of incidental cystic liver tumors in the general population

Aim of this study was to investigate frequency, incidence and risk factors of liver cysts in the general population in a longitudinal survey. Cyst frequency was investigated in 607 adult volunteers (288 women, 319 men, mean age 55 years) using strong T2-weighted magnetic resonance imaging. Risk factors were investigated for occurrence, frequency and size of cystic lesions at baseline. Incidence and physiological growing of the lesions were observed in a 5-years follow-up. At baseline, 431 volunteers had 1,479 cysts (71.0%). The mean number of cysts per person was 3.4 ± 9.0. The mean size of cysts was 13.1 ± 11.7 mm. Women had a higher number of cysts than men (p = 0.026). Older and male volunteers demonstrated a higher cyst frequency (p = 0.002 and p = 0.025). Per one-year increase in age the chance for a liver cyst increased by 2%. Four-hundred seventeen volunteers had cysts in the follow-up, in 24.6% new lesions had occurred. Lesion size significantly increased in follow-up (p < 0.001). Age and male sex were associated with the occurrence of at least one liver cyst. Women had a higher average number of cysts. Cystic lesion progression is a physiological phenomenon in the long-term follow-up.

Rare cause of cystic liver lesions: Liver metastasis of gastrointestinal stromal tumors

Gastrointestinal stromal tumors (GISTs) are rare mesenchymal neoplasms of the gastrointestinal tract with an annual incidence of 1–2 per 10 000 people. Although most GISTs are solid, they may present with predominantly cystic components. A 69‐year‐old Japanese woman presented with a recently elevated gamma‐glutamyl transpeptidase level. Computed tomography revealed multiple space‐occupying lesions (SOLs) in the liver. These SOLs appear cystic on magnetic resonance imaging and abdominal ultrasound and are associated with thick walls at the margins. In addition, these thick walls showed high intensity on diffusion‐weighted images. She was diagnosed with liver metastasis of GIST by diagnostic biopsies from the thick parts of the cystic liver lesion (thick walls at the margins). The primary lesion was thought to be located along the medial side of the descending part of the duodenum, but a duodenal biopsy was initially undiagnosed. Liver metastases due to GISTs are known to cause cystic changes after treatment, such as imatinib mesylate. However, to the best of our knowledge, only six cases where hepatic GIST with predominantly cystic changes (prior to any treatment) have been reported. It should be noted that GISTs appear cystic in all organs.

Guidelines and Good Clinical Practice Recommendations for Contrast Enhanced Ultrasound (CEUS) in the Liver - Update 2020 - WFUMB in Cooperation with EFSUMB, AFSUMB, AIUM, and FLAUS

The present, updated document describes the fourth iteration of recommendations for the hepatic use of contrast enhanced ultrasound (CEUS), first initiated in 2004 by the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB). The previous updated editions of the guidelines reflected changes in the available contrast agents and updated the guidelines not only for hepatic but also for non-hepatic applications.The 2012 guideline requires updating as previously the differences of the contrast agents were not precisely described and the differences in contrast phases as well as handling were not clearly indicated. In addition, more evidence has been published for all contrast agents. The update also reflects the most recent developments in contrast agents, including the United States Food and Drug Administration (FDA) approval as well as the extensive Asian experience, to produce a truly international perspective.These guidelines and recommendations provide general advice on the use of ultrasound contrast agents (UCA) and are intended to create standard protocols for the use and administration of UCA in liver applications on an international basis to improve the management of patients.

Guidelines and Good Clinical Practice Recommendations for Contrast-Enhanced Ultrasound (CEUS) in the Liver-Update 2020 WFUMB in Cooperation with EFSUMB, AFSUMB, AIUM, and FLAUS

The present, updated document describes the fourth iteration of recommendations for the hepatic use of contrast-enhanced ultrasound, first initiated in 2004 by the European Federation of Societies for Ultrasound in Medicine and Biology. The previous updated editions of the guidelines reflected changes in the available contrast agents and updated the guidelines not only for hepatic but also for non-hepatic applications. The 2012 guideline requires updating as, previously, the differences in the contrast agents were not precisely described and the differences in contrast phases as well as handling were not clearly indicated. In addition, more evidence has been published for all contrast agents. The update also reflects the most recent developments in contrast agents, including U.S. Food and Drug Administration approval and the extensive Asian experience, to produce a truly international perspective. These guidelines and recommendations provide general advice on the use of ultrasound contrast agents (UCAs) and are intended to create standard protocols for the use and administration of UCAs in liver applications on an international basis to improve the management of patients.

A case of hemorrhage of hepatocellular carcinoma resembling a hepatic cyst arising from non-cirrhotic steatohepatitis

A 70-year-old female was found to have multiple hepatic cysts at her annual checkup. In the posterior segment of the right lobe of the liver, an 81 × 67 mm circular cystic lesion was detected by contrast-enhanced computed tomography (CT). Magnetic resonance imaging (MRI) of the cyst revealed a solid component. The cyst had a capsule-like structure and non-uniform fluid accumulation suggested bleeding. Since the lesion was enlarged and malignancy could not be ruled out, it was surgically resected. Histopathologically, reticular fibers of the liver were seen in necrotic tissue and the lesion was diagnosed as a bleeding hepatocellular carcinoma (HCC). The non-cancerous liver tissue showed non-cirrhotic steatohepatitis. This was an unusual presentation of HCC.

Ecografía en cirugía general

La ecografía es un estudio de imágenes diagnósticas con una amplia historia de uso en todas las especialidades de la Medicina; su advenimiento ha ayudado al enfoque diagnóstico e, incluso, al abordaje terapéutico de los pacientes. Desde su origen en el siglo XIX con mediciones de la velocidad del sonido en el agua, hasta el desarrollo de las máquinas de ultrasonografía sustentadas en los avances de la tecnología, la física y la ingeniería, se ha utilizado de manera notable en la Medicina. No hay duda de que, en el campo de la Cirugía General, ha sido útil para el manejo de los pacientes con enfermedad abdominal. La tecnología ecográfica permite identificar las características de un órgano normal y, cuando este patrón se afecta, orienta sobre la causa o determina la enfermedad que puede estar produciendo la alteración. En la presente revisión, se hace un recuento histórico del nacimiento de la ecografía, su aplicación en el campo de la medicina y su utilidad para el cirujano general en diversas circunstancias de la práctica quirúrgica.

Giant hepatic cyst as a cause of gastric outlet obstruction

We describe the case of a 58-year-old female who presented to her primary care provider with lifelong anorexia, 6-week history of liquid only diet and new onset epigastric abdominal pain radiating to the back accompanied by nausea and abdominal distension. An initial computed tomography scan with contrast demonstrated a massive simple hepatic cyst with mass effect compression of the duodenal sweep. Repetitive treatment with aspiration sclerotherapy using hypertonic saline provided initial resolution of symptoms and led to substantial reduction of cyst diameter. Repeat imaging demonstrated complete drainage of the cyst and decompression of the duodenum. Ultimately, the patient's symptoms returned 6 weeks later at which time she opted for surgical deroofing of the cyst. Surgery provided for complete resolution. This case appears to be the first to document the compression of second portion of the duodenum by a massive simple hepatic cyst causing anorexia and mimicking gastric outlet obstruction.

Biliary Mucinous Cystadenoma: A Review of the Literature

Biliary mucinous cystadenomas are cystic neoplasms commonly mistaken for simple cysts. They are rare and generally benign tumors, often incidentally found on imaging and during unrelated surgical interventions. They tend to be slow growing though may reach symptomatic dimensions. Misdiagnosis of biliary mucinous cystadenomas may have serious consequences secondary to their potential for malignant transformation into biliary mucinous cystadenocarcinomas. Here, we review the epidemiology, etiology, pathology, diagnostic modalities, histology, and available treatment methods for mucinous cystadenomas reported in current literature.

Morphological and dynamic evaluation of complex cystic focal liver lesions by contrast-enhanced ultrasound: current state of the art

Complex cystic and cystic-like focal liver lesions (FLLs) encompass a spectrum of disorders ranging from non-neoplastic conditions to benign and malignant tumors. In this prospective, the possibility of non-invasive differentiation of these lesions is extremely important, because the clinical implications and therapeutic strategies vary considerably. Because of its advantageous cost/benefit ratio, widespread availability and easy execution, ultrasound (US) is the first-line imaging modality in most countries for the initial liver survey and represents the imaging technique that usually detects a complex liver cyst. However, US showed poor efficacy in the differential diagnosis of complex cystic FLLs. Thus, for years, computed tomography (CT) and magnetic resonance (MR) imaging have been used for further assessment of these lesions. Recently, the development of low mechanical index real-time contrast-enhanced ultrasound (CEUS) technique performed with the second generation of US contrast agents has led to an accurate depiction of macrovasculature and microvasculature. The technique yields information about contrast enhancement of the liver and FLLs almost as CT and MRI do, but in real time and without the use of ionizing radiation. To date, there is only a small amount of evidence about the role of CEUS in the less common setting of complex liver cysts. The aim of this review is to offer an up-to-date overview on the state of the art of CEUS in the study of the most common complex cystic focal liver lesions. To our knowledge, there are no literature comprehensive reviews on this topic.

A case of pseudocystic liver metastases from an atypical lung carcinoid tumor

Metastatic neuroendocrine tumors of the liver typically appear as solid, hypervascular masses on imaging. Pseudocysts mimicking simple cysts are extremely rare. A 42-year-old Japanese woman was referred with a single pulmonary mass in the left lower lobe. No metastatic lesion was detected and no occupying lesion in the liver was observed. The lung tumor was diagnosed as an atypical carcinoid. Postoperative investigation revealed new hepatic simple cysts in the liver, which increased in size over time and changed into hemorrhagic cysts. Fluorodeoxyglucose positron emission tomography and somatostatin receptor scintigraphy using 111In-octreotide demonstrated no accumulation in the liver. Our patient did not have symptoms consistent with carcinoid syndrome. The patient underwent partial resection of the cystic lesions of the liver. Gross examination of the tumors demonstrated thin-wall cavitated lesions with hemorrhage which were metastases from the atypical carcinoid of the lung. When a growing cystic lesion with intracystic hemorrhage is found in the liver of a patient with a history of carcinoid tumors, pseudocysts caused by degeneration of a carcinoid metastasis should be considered as a differential diagnosis.

An updated review of cystic hepatic lesions

Cystic hepatic lesions are commonly encountered in daily practice. The diagnosis of these lesions ranges from benign lesions of no clinical significance to malignant and potentially lethal conditions. The prevalence of hepatic cyst (HC) has been reported to be as high as 15-18% in the United States. Imaging with conventional ultrasound, computed tomography, magnetic resonance imaging, or contrast-enhanced ultrasound can be used to characterize further and diagnose. The pre-test probability of a diagnosis is highly affected by the patient's comorbidities and the clinical and laboratory data; thus, imaging studies should be interpreted in the context of the other clinical information for that particular patient. Treatment modalities for hepatic cyst include fenestration, aspiration sclerotherapy, or surgical resection. In the current review, we discuss the pathophysiology, diagnosis, and treatment modalities for various cystic hepatic lesions.

Uncommon evolutions and complications of common benign liver lesions

Frequently encountered on abdominal imaging studies, the majority of common benign liver lesions are asymptomatic, confidently diagnosed by imaging, and do not require further workup, follow-up, or treatment. The increasing use of multimodality liver imaging, has allowed the recognition of uncommon evolutions of common benign liver lesions such as size changes, fibrotic regression, and content and vascularization changes, and their complications such as rupture, hemorrhage, thrombosis, extrinsic compression, and malignancy. The purpose of this pictorial review is to describe and illustrate the incidence and diagnostic features of these uncommon evolutions and complications on cross-sectional imaging, mainly on computed tomography and magnetic resonance imaging, with emphasis on those imaging clues which are helpful in the differential diagnosis or indicate the need for treatment.

Infectious Hepatic Cyst: An Underestimated Complication

Objective An infectious hepatic cyst (IHC) is a hepatic cyst complicated with secondary infection and is generally assumed to be rare. However, we have experienced no small number of patients with IHC in recent clinical practice. We therefore examined the incidence and clinical characteristics of IHC. Methods The medical records of patients with IHC who were hospitalized at our institution between January 2012 and December 2016 were retrospectively reviewed. Their demographic factors, biochemical, bacteriological, imaging, and treatment results were explored and compared with those of patients with pyogenic liver abscess (PLA). Patients Twelve patients with IHC and 39 with PLA were identified. Results The IHCs were significantly larger in diameters than the PLAs, and patients with IHCs tended to be older and more often women than those with PLAs. IHCs showed characteristic imaging features, including heterogeneous contents with occasional fluid-debris levels, a thickened cystic wall with rim enhancement, perilesional edema and hyperaemia. Patients with IHCs had a significantly shorter hospital stay than those with PLAs. Conclusion Physicians should note that IHCs are not rare. A careful imaging evaluation can suggest an IHC, and the timely aspiration of the content can lead to an accurate diagnosis. The cystic wall may keep the infectious material confined within the IHC, resulting in the observed good treatment outcome with catheter drainage.

Differentiating metastatic mucinous colorectal adenocarcinomas from simple cysts of the liver using contrast-enhanced and diffusion-weighted MRI

OBJECTIVE:

To determine the value of contrast-enhanced and diffusion-weighted (DW) MRI for differentiating metastatic mucinous colorectal adenocarcinomas from simple cysts of the liver.

METHODS:

29 patients with 47 metastatic mucinous colorectal adenocarcinomas and/or 19 simple cysts of the liver who underwent contrast-enhanced and DW MRI were included in this retrospective study. Two radiologists assessed the MRI findings by consensus. Qualitative and quantitative analyses were conducted. Significant MRI findings on univariate and multivariate analyses were assessed, and their diagnostic performances for predicting metastatic mucinous colorectal adenocarcinomas were analyzed.

RESULTS:

The presence of rim enhancement (odds ratio, 28.43; p = 0.008) and intracystic enhancement (oddsratio, 180.15; p = 0.001) were independently significant factors for predicting metastatic mucinous colorectal adenocarcinomas. The sensitivity and specificity of rim enhancement, intracystic enhancement, and their combination for detecting metastatic mucinous colorectal adenocarcinomas were 83% (39/47) and 63.2% (12/19), 87.2% (41/47) and 89.5% (17/19), and 72.3% (34/47) and 94.7% (18/19), respectively. Compared to simple cysts, metastatic mucinous colorectal adenocarcinomas showed significantly lower mean apparent diffusion coefficient (1.92 ± 0.81 vs 2.99 ± 0.75 × 10^-3 mm² s^-1; p = 0.001) and lesion-to-liver apparent diffusion coefficient ratio (1.66 ± 0.75 vs 2.44 ± 0.56 × 10^-3 mm² s^-1; p = 0.004) and higher mean signal intensity (400.3 ± 216.3 vs 222.4 ± 99.3; p = 0.039) and lesion-to-liver signal intensity ratio on hepatobiliary-phase images (0.58 ± 0.16 vs 0.30 ± 0.14; p < 0.001).

CONCLUSION:

Contrast-enhanced and DW MRI may be helpful for differentiating metastatic mucinous colorectal adenocarcinomas from simple cysts of the liver.

ADVANCES IN KNOWLEDGE:

On contrast-enhanced and DW MRI, rim and intracystic enhancement can be helpful for differentiating metastatic mucinous colorectal adenocarcinomas from simple cysts of the liver.

Differentiating Cystic Liver Lesions: A Review of Imaging Modalities, Diagnosis and Management

Hepatic cysts (HCs) are frequently discovered incidentally on abdominal imaging. The prevalence of HCs has been reported as high as 15-18% in the United States. Although most cysts are benign, some are malignant or premalignant. It is important to diagnose cystic lesions in order to properly manage them. Imaging with conventional ultrasound, computed tomography, magnetic resonance imaging, or contrast-enhanced ultrasound can be used to further characterize and diagnose HCs. Ultrasound is typically the first-line imaging modality, whereas more advanced imaging can help narrow down the specific lesion. Contrast-enhanced ultrasound is a newer modality, recently approved in the United States, which offers non-invasive evaluation in real-time. The first step in diagnosis is stratifying risk by differentiating simple and complex cysts. There are several features that can help identify HCs, including septae, mural consistency, calcifications, and quality of cystic fluid. Simple cysts are mainly congenital cysts, but also occur in polycystic liver disease. Complex cysts include mucinous neoplasms, echinococcal cysts, hemorrhagic cysts, cystic hepatocellular carcinoma and other rare lesions. Treatment is indicated in symptomatic cysts or those suspicious for malignant or premalignant features. Treatment modalities include fenestration, aspiration sclerotherapy, or surgical resection.

Clinical management of polycystic liver disease

A 41-year old female underwent a computed tomography (CT) scan in 2010 because of symptoms suggestive of appendicitis. Incidentally, multiple liver lesions characterised as cysts were detected. The presence of small to medium sized liver cysts (diameter between <1 cm and 4 cm) in all liver segments (>100 cysts) and absence of kidney cysts in the context of normal renal function led to the clinical diagnosis of autosomal dominant polycystic liver disease (ADPLD). Five years later she was referred to the outpatient clinic with increased abdominal girth, pain in the right upper abdomen and right flank, and early satiety. She had difficulties bending over and could neither cut her toenails nor tie her shoe laces. In her early twenties she had used oral contraception for five years. She has been pregnant twice. Clinical examination showed an enlarged liver reaching into the right pelvic region and crossing the midline of the abdomen. Laboratory testing demonstrated increased gamma-glutamyl transferase (80 IU/L, normal <40 IU/L) and alkaline phosphatase (148 IU/L, normal <100 IU/L) levels. Bilirubin, albumin and coagulation times were within the normal range. A new CT scan in 2015 was compatible with an increased number and size of liver cysts. The diameter of cysts varied between <1 cm and 6 cm (anatomic distribution shown [Fig. 2B]). There were no signs of hepatic venous outflow obstruction, portal hypertension or compression on the biliary tract. Height-adjusted total liver volume (htTLV) increased from 2,667 ml/m in 2012 to 4,047 ml/m in 2015 (height 172 cm). The case we present here is not uncommon, and prompts several relevant questions.

Liver Masses: What Physicians Need to Know About Ordering and Interpreting Liver Imaging

PURPOSE OF REVIEW

This paper reviews diagnostic imaging techniques used to characterize liver masses and the imaging characteristics of the most common liver masses.

RECENT FINDINGS

The role of recently adopted ultrasound and magnetic resonance imaging contrast agents will be emphasized. Contrast-enhanced ultrasound is an inexpensive exam which can confirm benignity of certain liver masses without ionizing radiation. Magnetic resonance imaging using hepatocyte-specific gadolinium-based contrast agents can help confirm or narrow the differential diagnosis of liver masses.

Genetics and mechanisms of hepatic cystogenesis

Polycystic liver disease (PLD) is a heterogeneous genetic condition. PKD1 and PKD2 germline mutations are found in patients with autosomal dominant polycystic kidney disease (ADPKD). Autosomal dominant polycystic liver disease (ADPLD) is associated with germline mutations in PRKCSH, SEC63, LRP5, and recently ALG8 and SEC61. GANAB mutations are found in both patient groups. Loss of heterozygosity of PLD-genes in cyst epithelium contributes to the development of hepatic cysts. A genetic interaction network is implied in hepatic cystogenesis that connects the endoplasmic glycoprotein control mechanisms and polycystin expression and localization. Wnt signalling could be the major downstream signalling pathway that results in hepatic cyst growth. PLD in ADPLD and ADPKD probably results from changes in one common final pathway that initiates cyst growth. This article is part of a Special Issue entitled: Cholangiocytes in Health and Diseaseedited by Jesus Banales, Marco Marzioni, Nicholas LaRusso and Peter Jansen.

Diagnostic Performance and Confidence of Contrast-Enhanced Ultrasound in the Differential Diagnosis of Cystic and Cysticlike Liver Lesions

OBJECTIVE

The aims of this study were to assess the diagnostic performance of contrast-enhanced ultrasound (CEUS) in the characterization of atypical cystic and cysticlike focal liver lesions in comparison with conventional US and to determine whether the use of CEUS can reduce the need for further diagnostic workup.

SUBJECTS AND METHODS

In a 3-year period 48 patients with 50 atypical cystic and cysticlike lesions found at conventional US underwent CEUS. Diagnostic confirmation was obtained in cytohistopathologic examinations, with other imaging modalities, and in follow-up. Overall, there were 24 cystic lesions and 26 cysticlike solid lesions, specifically 32 benign and 18 malignant lesions. The conventional US and CEUS images and cine loops were reviewed by two blinded readers independently. Sensitivity, specificity, area under the ROC curve (A_z), and interobserver agreement were calculated.

RESULTS

Diagnostic performance improved after review of CEUS examinations by both readers (conventional US A_z = 0.781 vs 0.972; CEUS A_z = 0.734 vs 0.957). Interreader agreement increased, although slightly (conventional US weighted κ = 0.894; CEUS weighted κ = 0.953). In terms of differential diagnosis, the occurrence of correctly characterized lesions increased after CEUS for both readers (reader 1, 62% to 98%; reader 2, 56% to 96%).

CONCLUSION

The development of low-acoustic-power CEUS has made it possible to identify several imaging features of cystic and cysticlike focal liver lesions that, in association with history and clinical findings, may help to correctly characterize them. Our data indicate the usefulness of CEUS in the evaluation of patients with these lesions.

Contrast enhanced ultrasound features of hepatic cystadenoma and hepatic cystadenocarcinoma

OBJECTIVE

Hepatic (biliary) cystic tumor (HBCT) is a rare focal cystic liver lesion, which has been rarely described in the literature. In our current multicenter, retrospective study, we aimed to analyze contrast enhanced ultrasound (CEUS) features and its diagnostic performance in histologically proved HBCT.

MATERIAL AND METHODS

Twenty-three patients with single HBCT were retrospectively analyzed. Histologically, 17 (73.9%) were benign hepatic (biliary) cystadenoma (HBCA), 6 (26.1%) were hepatic (biliary) cystadenocarcinoma (HBCAC). All CEUS examinations were assessed by two independent radiologists in consensus. Criteria of CEUS imaging evaluation included the contrast enhancement pattern of lesion (hypoenhancing, hyperenhancing, isoenhancing in comparison to the surrounding liver parenchyma) during the arterial, portal venous and late phases.

RESULTS

After injection of ultrasound contrast agents, most of the HBCTs (78.3%, 18/23) had typical honeycomb enhancement pattern of the cystic wall, septa or mural nodules. Comparing between HBCA and HBCAC, hyperenhancement of the honeycomb septa during the arterial phase was more common in HBCA (p = .047). However, hypoenhancement during the portal venous and late phases was the characteristic of HBCAC (p = .041).

CONCLUSIONS

The EFSUMB algorithm for CEUS for characterization of solid focal liver lesions is also applicable to HBCT. CEUS evaluation can avoid further diagnostic investigations or invasive biopsy procedure.

Contrast-Enhanced Magnetic Resonance Cholangiography: Practical Tips and Clinical Indications for Biliary Disease Management

Since its introduction, MRCP has been improved over the years due to the introduction of several technical advances and innovations. It consists of a noninvasive method for biliary tree representation, based on heavily T2-weighted images. Conventionally, its protocol includes two-dimensional single-shot fast spin-echo images, acquired with thin sections or with multiple thick slabs. In recent years, three-dimensional T2-weighted fast-recovery fast spin-echo images have been added to the conventional protocol, increasing the possibility of biliary anatomy demonstration and leading to a significant benefit over conventional 2D imaging. A significant innovation has been reached with the introduction of hepatobiliary contrasts, represented by gadoxetic acid and gadobenate dimeglumine: they are excreted into the bile canaliculi, allowing the opacification of the biliary tree. Recently, 3D interpolated T1-weighted spoiled gradient echo images have been proposed for the evaluation of the biliary tree, obtaining images after hepatobiliary contrast agent administration. Thus, the acquisition of these excretory phases improves the diagnostic capability of conventional MRCP-based on T2 acquisitions. In this paper, technical features of contrast-enhanced magnetic resonance cholangiography are briefly discussed; main diagnostic tips of hepatobiliary phase are showed, emphasizing the benefit of enhanced cholangiography in comparison with conventional MRCP.

Predictors of treatment response following aspiration sclerotherapy of hepatic cysts: an international pooled analysis of individual patient data

Objectives

To identify predictive variables of treatment response following aspiration sclerotherapy of large symptomatic hepatic cysts.

Methods

We collected individual patient data from two tertiary referral centres and included all patients treated with aspiration sclerotherapy of a large (>5 cm), symptomatic hepatic cyst. At six months, clinical response was defined as complete or incomplete. Secondary, suboptimal technical response was defined as lower quartile of cyst reduction. Predictive variables of clinical and technical response were analyzed by logistic regression analysis.

Results

We included 86 patients (58 ± 10 years; female 90 %). Complete clinical response rate was 55 %. Median cyst diameter and volume reduction were 71 % (IQR 50-87 %) and 98 % (IRQ 88-100 %), respectively. Patients with complete clinical response had a significantly higher cyst reduction compared to incomplete responders (OR 1.02, 95 % CI 1.00-1.04). Aspiration of haemorrhagic cyst fluid (OR 4.39, 95 % CI 1.34-14.39) or a lower cyst reduction at one month (OR 1.06, 95 % CI 1.02-1.10) was associated with a suboptimal technical response at six months.

Conclusion

Complete clinical response is associated with effective cyst reduction. Aspiration of haemorrhagic cyst fluid or a restricted diameter reduction at one month predicts a suboptimal technical treatment response, however, these variables did not predict symptom disappearance.

Key Points

• Aspiration sclerotherapy of hepatic cysts shows excellent clinical and technical efficacy.

• Optimal clinical responders have a markedly higher cyst reduction.

• Haemorrhagic aspirate and a strong fluid reaccumulation predict suboptimal cyst reduction.

Electronic supplementary material

The online version of this article (doi:10.1007/s00330-016-4363-x) contains supplementary material, which is available to authorized users.

Mucinous Cystic Neoplasm of the Liver Masquerading as an Echinococcal Cyst: Radiologic-pathologic Differential of Complex Cystic Liver Lesions

Although simple liver cysts are common, complex cystic liver lesions are infrequent and represent a diagnostic and therapeutic challenge. The differential diagnosis of complex cystic liver lesions can be grouped into neoplastic, infectious or inflammatory, and miscellaneous pathologic entities. Clinicians should remember to consider mucinous cystic neoplasm and echinococcal cysts in the differential, which are uncommon etiologies for liver lesions but may expose unique challenges. We present a case of a 49-year-old female who was referred for evaluation of a new complex cystic liver lesion. The following brief review describes how radiologic imaging and pathologic testing can help distinguish between the broad spectrum of diseases that may produce cystic liver lesions.

Rectal melanoma presenting as a solitary complex cystic liver lesion: role of contrast-specific low-MI real-time ultrasound imaging

Cystic hepatic metastases arising from malignant melanoma are extremely rare, with the few such cases reported in the literature to date describing indeterminate imaging findings, being focused more on computed tomography. To the best of our knowledge, there is no prior report describing contrast-enhanced ultrasound findings of a solitary cystic liver metastasis from a primary rectal melanoma. We herein describe a case of a 41-year-old patient with a rectal melanoma, in whom the first manifestation of disease was a solitary complex cystic liver metastasis incidentally detected by ultrasound. On admission, our patient was free of specific symptoms and his laboratory test was normal. In this setting, contrast-enhanced ultrasound showed some distinctive features that helped us to make the correct diagnosis, confirmed subsequently by FNAC examination, thus allowing to provide the correct management for our patient. Although cystic metastases are rare, knowledge of CEUS imaging findings will be invaluable for radiologists and other medical subspecialties that may face such cases in the future in helping to provide adequate management for affected patients.

[Modern diagnostics of cystic liver lesions and hemangiomas]

CLINICAL ISSUE

Cystic liver lesions incorporate a broad heterogeneous group of mostly benign but also malignant abnormalities. The radiological aim is the non-invasive diagnosis with the use of different imaging modalities to determine the type of lesion.

STANDARD RADIOLOGICAL METHODS

The common generally asymptomatic incidental findings of cystic lesions on ultrasound, computed tomography (CT) and magnetic resonance imaging (MRI) must be classified on the basis of specific imaging features. Such a differentiation is essential because the clinical consequences and the appropriate therapy can vary depending on the underlying pathology. Due to the morphological overlap of many cystic lesions, conventional radiological methods are often insufficient.

METHODICAL INNOVATIONS

The huge advances in cross-sectional imaging (multidetector CT, MRI with special sequences and different contrast agents and MR cholangiopancreatography) in combination with the clinical history usually enable a non-invasive diagnosis. Pathognomonic morphological and hemodynamic lesion features, as well as a knowledge of the pathomechanisms, help to differentiate this broad spectrum of entities.

ACHIEVEMENTS

In this article the different entities of cystic liver lesions, together with the appropriate diagnostic method for detection and distinction and including their strengths and limitations, are demonstrated.

PRACTICAL RECOMMENDATIONS

A well-founded knowledge about the development of various cystic liver lesions and the suitable choice of imaging method facilitate a non-invasive diagnosis.

Focal liver lesions: Practical magnetic resonance imaging approach

With the widespread of cross-sectional imaging, a growth of incidentally detected focal liver lesions (FLL) has been observed. A reliable detection and characterization of FLL is critical for optimal patient management. Maximizing accuracy of imaging in the context of FLL is paramount in avoiding unnecessary biopsies, which may result in post-procedural complications. A tremendous development of new imaging techniques has taken place during these last years. Nowadays, Magnetic resonance imaging (MRI) plays a key role in management of liver lesions, using a radiation-free technique and a safe contrast agent profile. MRI plays a key role in the non-invasive correct characterization of FLL. MRI is capable of providing comprehensive and highly accurate diagnostic information, with the additional advantage of lack of harmful ionizing radiation. These properties make MRI the mainstay for the noninvasive evaluation of focal liver lesions. In this paper we review the state-of-the-art MRI liver protocol, briefly discussing different sequence types, the unique characteristics of imaging non-cooperative patients and discuss the role of hepatocyte-specific contrast agents. A review of the imaging features of the most common benign and malignant FLL is presented, supplemented by a schematic representation of a simplistic practical approach on MRI.