C-11 acetate does not enhance usefulness of F-18 FDG PET/CT in differentiating between focal nodular hyperplasia and hepatic adenoma. Clin Nucl Med. 2009;34:659-665. [PMID: 19893396 DOI: 10.1097/rlu.0b013e3181b53488]

Qualitative and quantitative differentiation efficiency of dual-tracer PET/CT with 18F-fluorodeoxyglucose and 11C-acetate for primary hepatocellular carcinoma: a systematic review and meta-analysis

PURPOSE

Primary hepatocellular carcinoma (HCC) represents a substantial global health challenge. Early diagnosis of HCC is crucial for improved patient outcomes. The aim of this study was to assess qualitative and quantitative diagnostic performance of PET/CT using 11C-acetate and [18F]-fluorodeoxyglucose (FDG) in detection of primary HCC and to determine if 11C-acetate added to [18F]-FDG alleviates the low sensitivity rate mentioned in guidelines.

METHODS

Protocol was pre-registered at https://osf.io/2vcb9 . We searched PubMed, Web of Science, Embase, and the Cochrane Library for included studies. Quality Assessment of Diagnostic Accuracy Studies 2 was used to assess the risk of bias. Possible sources of statistical heterogeneity were explored. Additionally, mentioned three PET/CT tests were evaluated for their diagnostic performance in differentiating HCC from its differential diagnoses. Grades of Recommendation, Assessment, Development, and Evaluation was used to assess quality of generated evidence.

RESULTS

Twenty-four studies were analyzed. Qualitative dual-tracer PET/CT demonstrated 92.0% per-lesion sensitivity, and a significantly higher direct sensitivity difference of 30% to conventional CT, 44.7% to [18F]-FDG, and 12.0% to 11C-acetate. Regarding differentiation rate, [18F]-FDG was superior to 11C-acetate in poorly differentiated lesions while 11C-acetate was superior in well-differentiated lesions. Regarding size, dual tracer combination solved the high missing rate of HCC lesions in 1-2 cm and 2-5 cm groups but could not help in size < 1 cm.

CONCLUSION

Dual-tracer PET/CT utilizing 11C-acetate and [18F]-FDG represents a sensitive method for detecting primary HCC. By concurrently quantifying or qualifying the uptake of 11C-acetate and [18F]-FDG, this multimodal approach enables precise localization of intrahepatic lesions.

Focal Nodular Hyperplasia: A Comprehensive Review with a Particular Focus on Pathogenesis and Complications

Focal nodular hyperplasia is a benign tumor of the liver that is often found incidentally with imaging. The purpose of this review is to discuss the pathophysiology, rare complications that can occur due to these lesions, and management options. A literature review was performed on clinical trials and case reports involving focal nodular hyperplasia complications and management of these, as well as the proposed pathogenesis underlying these tumors. Although exposure to oral contraceptive pills and endogenous hormones have been thought to play a role in the development of these lesions, this has not been proven. Most recently, they are thought to arise as a consequence of a vascular anomaly causing alterations in the expression of angiopoietin genes. Complications are rare, but previous cases have reported associated pain, rupture and compression of nearby structures (hepatic vein, stomach, biliary system). Resection of focal nodular hyperplasia is not usually recommended. However, if there is associated pain with no other identifiable cause or presence of a large or growing lesion with risk of causing a complication, then surgical resection, radiofrequency ablation or arterial embolization should be considered.

False-positive 18F fluorodeoxyglucose positron emission tomography-avid benign hepatic tumor: Previously unreported in a male patient

We report a case of ¹⁸F fluorodeoxyglucose (FDG) positron emission tomography (PET)–computed tomography-avid histologically confirmed inflammatory hepatic adenoma in a 77-year-old male patient without any history of steroid, alcohol use. This is the first case report of inflammatory hepatic adenoma in a male patient documented in the published literature showing uptake on ¹⁸F-FDG PET. Previous single case report of ¹⁸F-FDG PET-avid hepatic adenoma in a male patient was of hepatocyte nuclear factor-1-α subtype.

18F-FDG PET/CT of hepatocellular adenoma subtypes and review of literature

INTRODUCTION

This study evaluates 18F-FDG PET/CT imaging characteristics of pathologically proven hepatocellular adenoma (HCA) subtypes.

METHODS

This is a retrospective review of an institutional database (2011-2017) for subjects with a pathologic diagnosis of hepatic adenomas established within 6 months of a pre-treatment 18F-FDG PET/CT exam. An expert pathological review by a hepatopathologist was performed to confirm diagnosis and subtype HCA. A review of the 18F-FDG PET/CT exams was performed by two board-certified nuclear radiologists in consensus. Corresponding demographic and clinical data were obtained by electronic chart review.

RESULTS

Nine subjects were identified. An HCA subtype was established in seven subjects (4 HNF1A-mutated and 3 Inflammatory). The mean HCA lesion size was 2.8 cm (range 0.6-6.2, SD 2.0) with a mean SUVmax of 5.9 (range 2.1-18.9, SD 5.1). The SUV values of HNF1A-mutated HCA were significantly higher than inflammatory HCA: lesion SUVmax (5.3 ± 1.48 vs. 2.8 ± 0.59, p < 0.033), lesion-to-liver SUVmax ratio (1.4 ± 0.22 vs. 0.8 ± 0.21, p = 0.031), lesion SUVmean (3.6 ± 0.37 vs. 2.0 ± 0.46, p = 0.0086).

CONCLUSION

HNF1A-mutated HCA may have greater SUV values than inflammatory HCA on 18F-FDG PET/CT exams. However, there are contradictory data in the literature and further investigation is warranted.

FDG-PET/CT imaging findings of hepatic tumors and tumor-like lesions based on molecular background

The usefulness of whole-body 18-fluoro-2-deoxyglucose (FDG)-fluorodeoxyglucose positron emission (PET)/computed tomography (CT) is established for assessment of disease staging, detection of early disease recurrence, therapeutic evaluation, and predicting prognosis in various malignancies; and for evaluating the spread of inflammation. However, the role of FDG-PET/CT for the liver is limited because CT and magnetic resonance imaging (MRI) can provide an accurate diagnosis of most tumors. In addition, in other potentially useful roles there are several pitfalls in the interpretation of FDG uptake in PET/CT imaging. Accurate evaluation demands knowledge of the FDG uptake of each lesion, including potential negative and positive uptakes, and requires an understanding of the underlying background of the molecular mechanisms. The degree of FDG uptake is dependent on cellular metabolic rate and the expression of glucose transporter, hexokinase, and glucose-6-phosphatase, which in turn are closely affected by biological characteristics such as pathological category (e.g., adenocarcinoma, squamous cell carcinoma, small cell cancer, transitional cell cancer, neuroendocrine tumor, sarcoma, lymphoma), tumor differentiation, histological behavior (e.g., solid, cystic, mucinous), and intratumoral alterations (e.g., necrosis, degeneration, hemorrhage). Correlation with the CT and MRI findings, which also precisely depict the pathological findings, is important to avoid misdiagnosis.

18-Fluoro-deoxyglucose uptake in inflammatory hepatic adenoma: A case report

Positron emission tomography computed tomography (PET-CT) using 18-Fluoro-deoxyglucose (¹⁸FDG) is an imaging modality that reflects cellular glucose metabolism. Most cancers show an uptake of ¹⁸FDG and benign tumors do not usually behave in such a way. The authors report herein the case of a 38-year-old female patient with a past medical history of cervical intraepithelial neoplasia and pheochromocytoma, in whom a liver lesion had been detected with PET-CT. The tumor was laparoscopically resected and the diagnosis of inflammatory hepatic adenoma was confirmed. This is the first description of an inflammatory hepatic adenoma with an ¹⁸FDG up-take.

PET-avid hepatocellular adenomas: incidental findings associated with HNF1-α mutated lesions

BACKGROUND

Hepatocellular adenoma (HCA) is the second most common benign liver neoplasm and occurs predominantly in women in their reproductive years. Positron emission tomography (PET) using [18F] fluorodeoxyglucose (FDG) is commonly used in cancer staging, surveillance and evaluation of treatment response. PET-avid HCA are rare and can be falsely interpreted as malignancies.

METHODS

A retrospective review of four institutions' database was performed to identify the PET-avid HCAs with clinico-pathological correlation.

RESULTS

Nine patients with histological proven PET-avid HCA was identified. Eight out of 9 patients were female with a median age at diagnosis of 44 years. All patients' tumors with available histological subtyping (8/8) were HNF1-α mutated and had no inflammatory changes; 6 out the 9 lesions had prominent (>50%) steatotic changes.

CONCLUSION

Hepatocellular adenomas, specifically the HNF1-α subtype, can cause false-positive PET findings when seeking to identify malignancy. Concomitantly, PET-CT may have the potential to identify the HCA histopathologic variant with the lowest malignant and hemorrhagic potential.

PET-avid hepatocellular adenomas: incidental findings associated with HNF1-α mutated lesions

BACKGROUND

Hepatocellular adenoma (HCA) is the second most common benign liver neoplasm and occurs predominantly in women in their reproductive years. Positron-emission tomography (PET) using [18F] fluorodeoxyglucose (FDG) is commonly used in cancer staging, surveillance and evaluation of the treatment response. PET-avid HCA is rare and can be falsely interpreted as malignancies.

METHODS

A retrospective review of four institutions' database was performed to identify the PET-avid HCAs with clinico-pathological correlation.

RESULTS

Nine patients with histological proven PET-avid HCA was identified. Eight out of nine patients were female with a median age at diagnosis of 44 years. All patients' tumours with available histological subtyping (8/8) were HNF1-α mutated and had no inflammatory changes; six out the nine lesions had prominent (>50%) steatotic changes.

CONCLUSION

Hepatocellular adenomas, specifically the HNF1-α subtype, can cause false-positive PET findings when seeking to identify malignancy. Concomitantly, PET-CT may have the potential to identify the HCA histopathological variant with the lowest malignant and haemorrhagic potential.

Application of dual phase imaging of 11C-acetate positron emission tomography on differential diagnosis of small hepatic lesions

Objective

Previously we observed that dual phase ¹¹C-acetate positron emission tomography (AC-PET) could be employed for differential diagnosis of liver malignancies. In this study, we prospectively evaluated the effect of dual phase AC-PET on differential diagnosis of primary hepatic lesions of 1–3 cm in size.

Methods

33 patients having primary hepatic lesions with size of 1–3 cm in diameter undertook dual phase AC-PET scans. Procedure included an early upper-abdomen scan immediately after tracer injection and a conventional scan in 11–18 min. The standardized uptake value (SUV) was calculated for tumor (SUVT) and normal tissue (SUVB), from which ¹¹C-acetate uptake ratio (as lesion against normal liver tissue, SUVT/SUVB) in early imaging (R1), conventional imaging (R2), and variance between R2 and R1 (ΔR) were derived. Diagnoses based on AC-PET data and histology were compared. Statistical analysis was performed with SPSS 19.0.

Results

20 patients were found to have HCC and 13 patients had benign tumors. Using ΔR>0 as criterion for malignancy, the accuracy and specificity were significantly increased comparing with conventional method. The area under ROC curve (AUC) for R1, R2, and ΔR were 0.417, 0.683 and 0.831 respectively. Differential diagnosis between well-differentiated HCCs and benign lesions of FNHs and hemangiomas achieved 100% correct. Strong positive correlation was also found between R1 and R2 in HCC (r² = 0.55, P<0.001).

Conclusions

Dual phase AC-PET scan is a useful procedure for differential diagnosis of well-differentiated hepatocellular carcinoma and benign lesions. The dynamic changes of ¹¹C-acetate uptake in dual phase imaging provided key information for final diagnosis.

Hepatic adenoma mimicking a metastatic lesion on computed tomography-positron emission tomography scan

Positron emission tomography (PET) using ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) is an imaging modality which reflects cellular glucose metabolism. Most malignant cells accumulate and trap ¹⁸F-FDG, allowing the visualisation of increased uptake. It is hence widely used to differentiate malignant from benign lesions. “False positive” findings of hepatic lesions have been described in certain instances such as hepatic abscesses, but are rare in cases involving hepatocellular adenomas. To our knowledge, there have been only 7 reports in the English literature documenting PET-avid hepatocellular adenomas; 6 of the 7 reports were published in the last 3 years with the first report by Patel et al. We report the case of a 44-year-old Chinese female patient with a history of cervical adenocarcinoma, referred for a hepatic lesion noted on a surveillance computed tomography (CT) scan. A subsequent CT-PET performed showed a hypermetabolic lesion (standardized uptake value 7.9) in segment IVb of the liver. After discussion at a multi-disciplinary hepato-pancreato-biliary conference, the consensus was that of a metastatic lesion from her previous cervical adenocarcinoma, and a resection of the hepatic lesion was performed. Histology revealed features consistent with a hepatocyte nuclear factor-1 α inactivated steatotic hepatocellular adenoma.

Liver-specific contrast agent-enhanced magnetic resonance and ¹⁸F-fluorodeoxyglucose positron emission tomography findings of hepatocellular adenoma: report of a case

We report a case of hepatocellular adenoma, focusing on the findings of liver-specific contrast agent-enhanced magnetic resonance imaging (MRI) and ¹⁸F-fluorodeoxyglucose positron emission tomography (FDG-PET). The patient was a 37-year-old woman, referred to us after contrast-enhanced computed tomography showed a homogeneous, poorly enhanced liver tumor, 2.8 cm in diameter. Magnetic resonance imaging showed a liver mass with significant fatty change. The tumor increased in size to 3.3 cm over 9 months of follow-up. Gadolinium-ethoxybenzyl-diethylenetriamine penta-acetic acid-enhanced MRI revealed spotty enhancement in the hypointense tumor in the hepatobiliary phase. Subsequent FDG-PET showed increased uptake of FDG (maximum standardized uptake value 5.0), which suggested the possibility of malignancy. The patient underwent partial hepatectomy, and histological examination of the resected specimen revealed a tumor composed of hepatocyte-like cells with minimal cellular atypia and significant diffuse fatty change. Based on these findings, we diagnosed hepatocellular adenoma.

Focal nodular hyperplasia of the liver after intensive treatment for pediatric cancer: is hematopoietic stem cell transplantation a risk factor?

Focal nodular hyperplasia (FNH) is a benign hepatic lesion very rarely described in the pediatric population. It has been reported more frequently in patients treated for pediatric cancers with chemotherapy or hematopoietic stem cell transplantation. The use of high dosage of alkylating agents, the occurrence of venous occlusive disease, graft-versus-host disease, and other variables linked to the hematopoietic stem cell transplantation procedure can represent risk factors for the development of FNH in the pediatric age. The discovery of hepatic nodules in the follow-up of patients treated for malignancies suggests recurrence of disease and raises a diagnostic dilemma. Here we describe possible risk factors, clinical and radiological findings of eight pediatric patients who developed focal nodular hyperplasia after hematopoietic stem cell transplantation. The aim of this report is to provide useful diagnostic tools to facilitate accurate diagnosis of FNH and suggest a correct management of this benign lesion during postcancer follow-up.

Detection of hepatocellular carcinoma with PET/CT: a prospective comparison of 18F-fluorocholine and 18F-FDG in patients with cirrhosis or chronic liver disease

This prospective study aimed to compare the diagnostic performance of (18)F-fluorocholine and (18)F-FDG for detecting and staging hepatocellular carcinoma (HCC) in patients with chronic liver disease and suspected liver nodules.

METHODS

Whole-body PET/CT was performed in a random order at 10 min after injection of 4 MBq of (18)F-fluorocholine per kilogram and at 1 h after injection of 5 MBq of (18)F-FDG per kilogram. PET/CT results were read in a masked manner by 2 specialists, and diagnostic performance was assessed from the results of consensus masked reading. Those focal lesions appearing with increased or decreased activity, compared with background, on (18)F-fluorocholine PET/CT were considered positive for malignancy. The standard of truth was determined on a per-site basis using data from a histologic examination and a follow-up period of more than 6 mo; on a per-patient basis, the Barcelona criteria were also accepted as a proof of HCC in 5 patients.

RESULTS

Eighty-one patients were recruited; standard of truth was determined in 59 cases. HCC was diagnosed in 34 patients. Therefore, sensitivity was 88% for (18)F-fluorocholine and 68% for (18)F-FDG (P = 0.07), and in 70 sites, sensitivity was 84% for (18)F-fluorocholine, significantly better than the 67% for (18)F-FDG (P = 0.01). Of the 11 patients with well-differentiated HCC, 6 had a positive result with (18)F-fluorocholine alone, whereas (18)F-FDG was never positive alone; corresponding site-based sensitivity was 94% for (18)F-fluorocholine and 59% for (18)F-FDG (P = 0.001). The detection rate of 18 sites corresponding to other malignancies was 78% for (18)F-fluorocholine and 89% for (18)F-FDG. In nonmalignant sites, (18)F-fluorocholine appeared less specific than (18)F-FDG (62% vs. 91% P < 0.01) because of uptake by focal nodular hyperplasia.

CONCLUSION

(18)F-fluorocholine was significantly more sensitive than (18)F-FDG at detecting HCC, in particular in well-differentiated forms. In contrast, (18)F-FDG appeared somewhat more sensitive at detecting other malignancies and was negative in focal nodular hyperplasia. Thus (18)F-fluorocholine appears to be a useful PET/CT tracer for the detection and surveillance of HCC; however, performing PET/CT with both radiopharmaceuticals seems to be the best option.