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

Synthesis and biological evaluation of 68Ga-DOTA-AngII as a radiotracer for PET/MR imaging of hepatocellular carcinoma

The precise diagnosis of HCC is confronted with severe challenges due to the tumor heterogeneity and insidious symptoms of hepatocellular carcinoma (HCC), and meanwhile the limitations of positron emission tomography (PET) with traditional 2-deoxy-2-[fluorine-18] fluoro-d-glucose (18F-FDG) tracer. Given that angiotensin II type 1 receptor (AT1R) is significantly upregulated in HCC and closely related to its progression, we have developed a novel 68Ga-radiolabeled compound, 68Ga-DOTA-AngII (68Ga-DOTA-GGDRVYIHPF), and evaluated its HCC detection capability. 68Ga-DOTA-AngII demonstrated acceptable stability in both human plasma and phosphate buffered saline. In vivo imaging and in vitro biodistribution analysis in tumor-bearing mice showed that 68Ga-DOTA-AngII demonstrate a high tumor uptake, and the tumor tissue exhibited rapid uptake. In brief, this radiotracer possesses a promising potency for imaging the expression of AT1R for further clinical application.

Preliminary study on detection and diagnosis of focal liver lesions based on a deep learning model using multimodal PET/CT images

Objectives

To develop and validate a deep learning model using multimodal PET/CT imaging for detecting and classifying focal liver lesions (FLL).

Methods

This study included 185 patients who underwent 18F-FDG PET/CT imaging at our institution from March 2022 to February 2023. We analyzed serological data and imaging. Liver lesions were segmented on PET and CT, serving as the "reference standard". Deep learning models were trained using PET and CT images to generate predicted segmentations and classify lesion nature. Model performance was evaluated by comparing the predicted segmentations with the reference segmentations, using metrics such as Dice, Precision, Recall, F1-score, ROC, and AUC, and compared it with physician diagnoses.

Results

This study finally included 150 patients, comprising 46 patients with benign liver nodules, 51 patients with malignant liver nodules, and 53 patients with no FLLs. Significant differences were observed among groups for age, AST, ALP, GGT, AFP, CA19-9and CEA. On the validation set, the Dice coefficient of the model was 0.740. For the normal group, the recall was 0.918, precision was 0.904, F1-score was 0.909, and AUC was 0.976. For the benign group, the recall was 0.869, precision was 0.862, F1-score was 0.863, and AUC was 0.928. For the malignant group, the recall was 0.858, precision was 0.914, F1-score was 0.883, and AUC was 0.979. The model's overall diagnostic performance was between that of junior and senior physician.

Conclusion

This deep learning model demonstrated high sensitivity in detecting FLLs and effectively differentiated between benign and malignant lesions.

GLUT-1-negative Choroidal Malignant Melanoma with Liver Metastasis Recurrence 12 Years after Surgery without FDG Accumulation in a Recurrent Lesion on FDG-PET/CT

Choroidal malignant melanoma is a rare malignant tumor that develops in adult eyeballs. It causes early lymph node and distant metastasis. Fluorodeoxyglucose (FDG)-positron emission tomography/computed tomography (CT) is widely used for screening malignant melanoma metastases. We encountered a 58-year-old man with choroidal malignant melanoma in whom liver metastasis recurred 12 years after surgery, without any observable FDG accumulation. Immunostaining revealed the absence of glucose transporter type 1 (GLUT-1) expression, crucial for intracellular FDG uptake. The lack of FDG accumulation in the lesion could be attributed to the diminished cellular FDG uptake due to the absence of GLUT-1 expression.

Analysis of the best time-point for 18F-FDG PET/CT delayed imaging in patients of small colorectal cancer liver metastasis with hypothyroidism based on diagnostic efficacy and image standardized uptake values

OBJECTIVE

This study analyzes the role of positron emission tomography/computed tomography (PET/CT) in the diagnosis of small (< 10 mm) colorectal cancer liver metastasis (CRLM) lesions in patients with hypothyroidism. In particular, the impact of the best time for delayed imaging on improving diagnostic efficacy.

METHODS

We retrospectively analyzed 231 patients with small CRLM lesions with hypothyroidism who underwent dual time-point 18F-FDG PET/CT imaging. Based on the previous studies and clinical practice experience, 120-190 min was selected as the time range for delayed imaging, divided into eight teams in 10-min groups. The delayed images of the eight time periods were first analyzed and compared for diagnostic efficacy, and second analyzed and compared for standardized uptake value (SUV) and of PET/CT images to observe the trend of SUV values over time.

RESULTS

The results of diagnostic efficacy analysis indicated that the 180-min delay group had the highest diagnostic efficacy (sensitivity, specificity, and accuracy). Comparison of the SUV values with the delay time analysis showed that maximum standardized uptake value (SUVmax) increased with the delay time, and the normal liver tissue (SUVmean) decreased with the delay time, which resulted in the gradual increase in the ratio of the lesion to the normal liver tissue (TNR). By selecting the time-point with the highest TNR ratio and stable SUV value, and combining the results of diagnostic efficacy, this study successfully verified the best imaging time-point. After comprehensive consideration, 180 min was determined as the best imaging time-point, when the TNR reached the highest, the SUV value was stable, and the diagnostic efficacy was best.

CONCLUSIONS

In this study, the impact of delayed imaging on the diagnostic efficacy and SUV value of PET/CT images in patients of small CRLM with hypothyroidism was shown intuitively, and the changing pattern of SUV at different time points was also observed. The best time-point for PET/CT delayed imaging was determined to be 180 min, which provides a new scanning program for the diagnosis in patients of small CRLM with hypothyroidism.

Correlation of preoperative 18F-FDG-PET/CT tumor staging and maximum standardized uptake values with preoperative CT, postoperative tumor classification, and histopathological parameters of oral squamous cell carcinoma

INTRODUCTION

This study aimed to correlate preoperative 18F-fluorodeoxyglucose-positron emission tomography/computed tomography (18F-FDG-PET/CT) tumor staging, and maximum standardized uptake values (SUVmax) with preoperative CT data, postoperative tumor classification, and histopathological parameters of oral squamous cell carcinoma (OSCC).

MATERIAL AND METHODS

Thirty-seven OSCC patients staged via full-body 18F-FDG-PET/CT, including contrast agent CT of the head and neck in 2020 and 2021, were enclosed. Patients received tumor resection and stage-dependent neck dissection. Preoperative clinical (c) 18F-FDG-PET/CT UICC tumor stages and TNM classifications were correlated to corresponding CT and to postoperative histopathological (p) UICC tumor stages and TNM classifications. SUVmax of the primary tumor was associated with pUICC and pTNM, including extranodal extension (ENE), perineural invasion (Pn), lymphatic spread (L), vascular invasion (V), tumor grading (G), and -thickness.

RESULTS

Comparing 18F-FDG-PET/CT and CT, cUICC, cT, and cN differed in 32.3%, 16.7%, and 37.8% of the cases, respectively. For 18F-FDG-PET/CT, a moderate correlation was found between c- and pUICC (0.494; p = 0.0018) with a misestimation of c- compared to pUICC in 43.2% of the cases. Comparing c- and pTNM, misestimations concerning c- and pT were seen in 51.4% and concerning c- and pN in 37.8% of the cases. An increased SUVmax significantly correlated with increased pT- and pUICC (adjusted Odds ratio 1.103; p = 0.042 and 1.126; p = 0.021, respectively). The predictive quality of an SUVmax cutoff value for detecting cervical lymph node metastases and G was poor, as indicated by the low AUC values from the ROC analysis. No correlations were found between SUVmax and ENE, Pn-, L-, and V-status. A strong correlation was found between SUVmax and tumor thickness with an adjusted coefficient of 1.034 (p = 0.01).

CONCLUSION

The predictive value of 18F-FDG-PET/CT and SUVmax on histopathological tumor classification and parameters appears limited.

CLINICAL RELEVANCE

18F-FDG-PET/CT can not unreservedly be recommended for primary OSCC staging. There is an urgent need to specify its indications in detail further.

Pitfalls in Positron Emission Tomography/Computed Tomography in the Thorax and Abdomen

Positron emission tomography/computed tomography (PET/CT) using [18F]-fluoro-2-deoxy-D-glucose (FDG) has become the mainstay imaging modality for evaluating oncology patients with certain cancers. The most common FDG PET/CT applications include staging/restaging, assessing response to therapy and detecting tumor recurrence. It is important to be aware of potential pitfalls and technical artifacts on PET/CT in the chest and abdomen to ensure accurate interpretation, avoid unnecessary intervention and optimize patient care.

In Vivo Time-Resolved Fluorescence Detection of Liver Cancer Supported by Machine Learning

OBJECTIVES

One of the widely used optical biopsy methods for monitoring cellular and tissue metabolism is time-resolved fluorescence. The use of this method in optical liver biopsy has a high potential for studying the shift in energy-type production from oxidative phosphorylation to glycolysis and changes in the antioxidant defense of malignant cells. On the other hand, machine learning methods have proven to be an excellent solution to classification problems in medical practice, including biomedical optics. We aim to combine time-resolved fluorescence measurements and machine learning to automate the division of liver parenchyma and tumors (primary malignant, metastases and benign tumors) into classes.

MATERIALS AND METHODS

An optical biopsy was performed using a developed setup with a fine-needle optical probe in clinical conditions under ultrasound control. Fluorescence decays were recorded in a conditionally healthy liver and lesions during percutaneous needle biopsy. The labeled data set was created on the basis of the recorded fluorescence results and the histopathological classification of the biopsies obtained. Several machine learning methods were trained using different separation strategies of the training test set, and their respective accuracy was compared.

RESULTS

Our results show that each of the tumor types had its own characteristic metabolic shifts recorded by the time-resolved fluorescence spectroscopy. The application of machine learning demonstrates a reliable separation of the liver and all tumor types into cancer and noncancer classes with sensitivity, specificity and corresponding accuracy greater than 0.91, 0.79 and 0.90, using the random forest method. We also show that our method is capable of giving a preliminary diagnosis of the type of liver tumor (primary malignant, metastases and benign tumors) with a sensitivity, specificity and accuracy of at least 0.80, 0.95 and 0.90.

CONCLUSIONS

These promising results highlight its potential as a key tool in the future development of diagnostic and therapeutic strategies for liver cancers. Lasers Surg. Med. 00:00-00, 2024. 2024 Wiley Periodicals LLC.

Retrospective study of qualitative assessment in detecting synchronous and metachronous malignancies in adult cancer patients by 18 F-FDG PET/CT

OBJECTIVES

The study aimed to evaluate the frequency of incidental suspicious lesions detected by flourine-18 fluorodeoxyglucose PET/computed tomography ( 18 F-FDG PET/CT) scans done for staging or restaging in adult cancer patients. We further determined the detection rate of synchronous and metachronous malignancies in these suspicious lesions after further investigations.

MATERIALS AND METHODS

This retrospective analysis evaluated the consecutive patients with 18 F-FDG PET/CT scans done in Queen Elizabeth Hospital (QEH), Hong Kong between July 2021 and June 2022. The adult cancer patients who underwent staging or restaging 8 F-FDG PET/CT were included while the remaining were excluded. Patients' demographics, primary cancer type, tumor markers, and pathological analyses for the incidental suspicious lesions were reviewed to establish the detection rate of synchronous and metachronous malignancies.

RESULTS

A total of 2054 patients fulfilled inclusion criteria with age ranging from 18 to 93 years old. Out of the 2054 patients, 304 (14.8%) were found to have incidental suspicious lesions. Of these, 206 patients (67.8%) underwent further investigations including pathological analyses. Subsequently, 84 of these 206 patients (40.8%) had pathologically proven synchronous or metachronous malignancies.

CONCLUSION

The detection rate of incidental suspicious lesions in adult cancer patients who underwent 18 F-FDG PET/CT scans for staging or restaging was 14.8% and the rate of synchronous and metachronous malignancies in these suspicious lesions was 40.8%. The treatment plan of these patients may potentially be altered, which should be included in the cost-benefit analysis of using this imaging modality.

A paradigm shift in diagnosis and treatment innovation for mucinous cystic neoplasms of the liver

This study comprehensively explores the clinical characteristics, diagnostic approaches, and treatment methods for liver mucinous cystic neoplasms (MCN). A retrospective analysis was conducted on seven individuals diagnosed with MCN, admitted to the Fifth Medical Center of the PLA General Hospital between October 2016 and May 2023. Preoperative AFP was negative, while CA19-9 was elevated in two cases. Surgical resection was performed for all patients. The patients showed favorable postoperative recovery. Follow-up revealed an excellent overall survival rate, except for one case of invasive carcinoma resulting in tumor recurrence and metastasis 6 months after surgery. MCN poses a diagnostic challenge due to the absence of distinct clinical and radiological features, leading to potential misdiagnosis and inappropriate treatment. Patients with suspected liver cystic diseases should consider the possibility of MCN. Surgical resection has proven to be a practical approach with satisfactory therapeutic outcomes.

Analyzing the value of delayed 18 F-FDG PET/CT images in diagnosing small colorectal cancer liver metastases in patients with hypothyroidism based on diagnostic accuracy and image standardized uptake value

PURPOSE

The objective of this study was to investigate the value of delayed 18F fluorodeoxyglucose PET/computed tomography (18F-FDG PET/CT) images in patients with small colorectal cancer liver metastases (CRLMs) with hypothyroidism.

METHOD

We performed a retrospective analysis of 66 small-CRLM patients with hypothyroidism and 66 small-CRLM patients with euthyroidism, all of whom underwent dual-time-point 18 F-FDG PET/CT imaging. First, the diagnostic accuracy of PET/CT early imaging and PET/CT delayed imaging on lesions was analyzed. Next, the correlation of metabolic parameters between PET/CT early imaging and PET/CT delayed imaging was analyzed according to the grouping of all lesions. Finally, PET/CT parameters were analyzed for correlation with thyroid hormones.

RESULTS

The diagnostic accuracy of delayed imaging in small-CRLM patients with hypothyroidism is not as good as that in small-CRLM patients with euthyroidism; PET/CT metabolic parameters are also unfavorable for the diagnosis of small-CRLM. For small-CRLM patients with hypothyroidism, the greater the thyroid-stimulating hormone level, the greater the uptake of 18 F-FDG in normal liver tissue, and the smaller the ratio of tumor lesion uptake to normal liver tissue uptake.

CONCLUSION

PET/CT-delayed imaging has better performance than early imaging in small-CRLM patients with euthyroidism. However, the more severe the hypothyroidism, the worse the diagnostic delayed imaging performance. The scan time can be extended appropriately to optimize the imaging efficacy.

Patlak Slope versus Standardized Uptake Value Image Quality in an Oncologic PET/CT Population: A Prospective Cross-Sectional Study

Patlak slope (PS) images have the potential to improve lesion conspicuity compared with standardized uptake value (SUV) images but may be more artifact-prone. This study compared PS versus SUV image quality and hepatic tumor-to-background ratios (TBRs) at matched time points. Early and late SUV and PS images were reconstructed from dynamic positron emission tomography (PET) data. Two independent, blinded readers scored image quality metrics (a four-point Likert scale) and counted tracer-avid lesions. Hepatic lesions and parenchyma were segmented and quantitatively analyzed. Differences were assessed via the Wilcoxon signed-rank test (alpha, 0.05). Forty-three subjects were included. For overall quality and lesion detection, early PS images were significantly inferior to other reconstructions. For overall quality, late PS images (reader 1 [R1]: 3.95, reader 2 [R2]: 3.95) were similar (p > 0.05) to early SUV images (R1: 3.88, R2: 3.84) but slightly superior (p ≤ 0.002) to late SUV images (R1: 2.97, R2: 3.44). For lesion detection, late PS images were slightly inferior to late SUV images (R1 only) but slightly superior to early SUV images (both readers). PS-based TBRs were significantly higher than SUV-based TBRs at the early time point, with opposite findings at the late time point. In conclusion, late PS images are similar to early/late SUV images in image quality and lesion detection; the superiority of SUV versus PS hepatic TBRs is time-dependent.

Patlak Reconstruction Using Dynamic 18 F-FDG PET Imaging for Evaluation of Malignant Liver Tumors : A Comparison of HCC, ICC, and Metastatic Liver Tumors

PURPOSE OF THE REPORT

The aim of this study was to explore the different patterns of dynamic whole-body (D-WB) FDG PET/CT parameters among liver malignancy types as potential diagnostic clues and investigate the association between static and dynamic PET/CT parameters for each tumor histology.

PATIENTS AND METHODS

Seventy-one patients with intrahepatic cholangiocarcinoma (ICC), metastatic liver tumor (MLT), or hepatocellular carcinoma (HCC) who underwent D-WB and static dual-time-point FDG PET/CT were enrolled. We obtained Pearson correlation coefficients between the metabolic rate of FDG (MR FDG ; mg/min/ 100ml) or distribution volume of free FDG (DV FDG , %) and static PET/CT parameters. We compared MR FDG and DV FDG values by tumor type and performed receiver operating characteristic analyses for MR FDG and static images.

RESULTS

A total of 12 ICC, 116 MLT, and 36 HCC lesions were analyzed. MR FDG and DV FDG showed excellent correlation with early (SUV e ) and delayed SUV max (SUV d ) ( r = 0.71~0.97), but DV FDG in the HCC lesions did not ( r = 0.62 and 0.69 for SUV e and SUV d , respectively) ( P < 0.001 for all). HCC lesions showed significantly lower MR FDG (2.43 ± 1.98) and DV FDG (139.95 ± 62.58) than ICC (5.02 ± 3.56, 207.06 ± 97.13) and MLT lesions (4.51 ± 2.47, 180.13 ± 75.58) ( P < 0.01 for all). The optimal MR FDG could differentiate HCC from ICC and MLT with areas under the curve of 0.84 and 0.80, respectively. Metastatic liver tumor lesions showed the widest distribution of MR FDG and DV FDG values but with no significant difference among most primary sites.

CONCLUSIONS

MR FDG was strongly correlated with SUV max in the 3 malignancies and showed utility for differentiating HCC from ICC and MLT. Each tumor type has a different glucose metabolism, and D-WB FDG PET/CT imaging has the potential to visualize those differences.

A prospective study of 68Ga-PSMA PET/CT imaging of HCC as diagnosed on conventional imaging to evaluate for potential 177Lu-PSMA therapy

OBJECTIVE

PSMA expression is seen in many solid tumours in addition to prostate cancer and several studies and case reports have shown PSMA expression and 68Ga-PSMA imaging of hepatocellular carcinoma (HCC). Our prospective study evaluates the role of 68Ga-PSMA in HCC patients and compares it to conventional imaging (CE-CT/MRI).

METHODS

Patients with radiologically and/or histopathologically confirmed HCC were included and all had undergone serum alpha-fetoprotein (S.AFP) assessment as well as CE-CT/MRI prior to PSMA PET/CT. Acquired whole-body PET/CTs were analysed both visually and quantitatively by two experienced nuclear medicine physicians.

RESULTS

Forty-one (41) patients (36 male; 5 female) with known HCC and a mean age of 53.9 ± 10.9 years underwent 68Ga-PSMA PET/CT. All patients had lesions on conventional imaging but only 38/41 patients showed 68Ga-PSMA uptake. Conventional imaging revealed 18 patients with single lesions, all of which were tracer avid. Twenty-three (23) of 41 patients had multifocal (> 2) hepatic lesions on CE-CT/MRI of which 3 patients showed no 68Ga-PSMA uptake, 7 showed tracer uptake in a single lesion only and 13 patients had multifocal tracer avid lesions. There was no correlation observed between S. AFP level and tumour SUVmax on 68Ga-PSMA PET/CT.

CONCLUSION

68Ga-PSMA PET/CT imaging of HCC may complement conventional imaging and identify patients for potential theranostic intervention.

Hepatic Cavernous Hemangioma Mimicking Malignancy on 18 F-FDG PET/CT Imaging

ABSTRACT

A 65-year-old woman was referred to our hospital because of a liver lesion revealed by ultrasound and CT in an outside institution. 18 F-FDG PET/CT images revealed an FDG-avid lesion in the left lateral lobe of the liver. Malignancy cannot be excluded. A subsequent resection was performed to remove the lesion. Postoperative pathology was hepatic cavernous hemangioma. This case suggests that PET/CT findings of FDG-avid hepatic cavernous hemangioma could mimic malignancy.

Emerging theragnostic radionuclide applications for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a major global health problem. Theragnostic is a term that refers to the integration of diagnostic and therapeutic modalities into a single system for personalized medicine. Theragnostic care in HCC involves the use of imaging techniques to diagnose the cancer and assess its characteristics, such as size, location, and extent of spread. Theragnostics involves the use of molecular and genetic tests to identify specific biomarkers that can help guide treatment decisions and, post-treatment, assess the dosimetry and localization of the treatment, thus guiding future treatment. This can be done through either positron emission tomography (PET) scanning or single photon emission tomography (SPECT) using radiolabeled tracers that target specific molecules expressed by HCC cells or radioembolization. This technique can help identify the location and extent of the cancer, as well as provide information on the tumor's metabolic activity and blood supply. In summary, theragnostics is an emerging field that holds promise for improving the diagnosis and treatment of HCC. By combining diagnostic and therapeutic modalities into a single system, theragnostics can help guide personalized treatment decisions and improve patient outcomes.

Is Prone Position [18F]FDG PET/CT Useful in Reducing Respiratory Motion Artifacts in Evaluating Hepatic Lesions?

Prone position is useful in reducing respiratory motion artifacts in lung nodules on 2-Deoxy-2-[18F] fluoro-D-glucose ([18F]FDG) positron emission tomography/computed tomography (PET/CT). However, whether prone position PET/CT is useful in evaluating hepatic lesions is unknown. Thirty-five hepatic lesions from 20 consecutive patients were evaluated. The maximum standardized uptake value (SUVmax) and metabolic tumor volume (MTV) of both standard supine position PET/CT and additional prone position PET/CT were evaluated. No significant difference in SUVmax (4.41 ± 2.0 vs. 4.23 ± 1.83; p = 0.240) and MTV (5.83 ± 6.69 vs. 5.95 ± 6.24; p = 0.672) was observed between supine position PET/CT and prone position PET/CT. However, SUVmax changes in prone position PET/CT varied compared with those in supine position PET/CT (median, -4%; range: -30-71%). Prone position PET/CT was helpful when [18F]FDG uptake of the hepatic lesions was located outside the liver on supine position PET/CT (n = 4, SUVmax change: median 15%; range: 7-71%) and there was more severe blurring on supine position PET/CT (n = 6, SUVmax change: median 11%; range: -3-32%). Unlike in lung nodules, prone position PET/CT is not always useful in evaluating hepatic lesions, but it may be helpful in individual cases such as hepatic dome lesions.

FAPI PET Positivity in Fibrolamellar Hepatocellular Carcinoma

ABSTRACT

Fibrolamellar hepatocellular carcinoma (HCC) is a variant of HCC. It is a malignant tumor, but its imaging features often overlap focal nodular hyperplasia, which is a benign entity. FDG PET/CT is also not much help in these cases because both lesions do not concentrate FDG. We present one such case of fibrolamellar HCC with FAPI PET/CT positivity.

Artificial intelligence-powered software detected more than half of the liver metastases overlooked by radiologists on contrast-enhanced CT

PURPOSE

To evaluate the sensitivity of artificial intelligence (AI)-powered software in detecting liver metastases, especially those overlooked by radiologists.

METHODS

Records of 746 patients diagnosed with liver metastases (November 2010-September 2017) were reviewed. Images from when radiologists first diagnosed liver metastases were reviewed, and prior contrast-enhanced CT (CECT) images were checked for availability. Two abdominal radiologists classified the lesions into overlooked lesions (all metastases missed by radiologists on prior CECT) and detected lesions (all metastases if any of them were correctly identified and invisible on prior CECT or those with no prior CECT). Finally, images from 137 patients were identified, 68 of which were classified as "overlooked cases." The same radiologists created the ground truth for these lesions and compared them with the software's output at 2-month intervals. The primary endpoint was the sensitivity in detecting all liver lesion types, liver metastases, and liver metastases overlooked by radiologists.

RESULTS

The software successfully processed images from 135 patients. The per-lesion sensitivity for all liver lesion types, liver metastases, and liver metastases overlooked by radiologists was 70.1%, 70.8%, and 55.0%, respectively. The software detected liver metastases in 92.7% and 53.7% of patients in detected and overlooked cases, respectively. The average number of false positives was 0.48 per patient.

CONCLUSION

The AI-powered software detected more than half of liver metastases overlooked by radiologists while maintaining a relatively low number of false positives. Our results suggest the potential of AI-powered software in reducing the frequency of overlooked liver metastases when used in conjunction with the radiologists' clinical interpretation.

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.

Schwannoma in and around the porta hepatis: radiological features in eight cases and literature review

PURPOSE

Schwannomas in and around the porta hepatis (porta hepatic schwannomas) are rare benign tumors easily misdiagnosed as other pathologies, including malignancies. We aimed to evaluate their imaging features on ultrasonography, computed tomography (CT), magnetic resonance imaging (MRI), and ¹⁸F-fluorodeoxyglucose-positron emission tomography/CT (FDG-PET/CT).

METHODS

We performed a multi-institutional retrospective study by reviewing the clinical and imaging findings of pathologically proven eight porta hepatic schwannomas (mean age, 55 years; range, 38-80 years; one male and seven females). Preoperative imaging included three ultrasonography, eight CT, eight MRI, and two FDG-PET/CT.

RESULTS

All patients were asymptomatic. The mean tumor size was 61.9 mm (range, 30-180 mm), and all tumors demonstrated well-defined lesions on ultrasonography and their solid components showed soft tissue attenuation on non-contrast CT. MRI showed two distinct components in all cases: the component with T1-weighted hypointensities and T2-weighted hyperintensities with poor enhancement (suggestive of Antoni B histology); the component with T2-weighted hypointensities with gradually increasing enhancement (suggestive of Antoni A histology), resulting in a heterogeneous pattern on post-contrast CT or MRI (8/8, 100%). The separated deviation of surrounding bile ducts and vessels without obstruction allowed the recognition of extrahepatic localization and their benign nature. A ginger root-like morphology (2/8, 25%) seemed to be suggestive of extension along the Glisson's sheath, although this finding was not seen frequently.

CONCLUSION

Recognizing imaging features such as extrahepatic location, benign nature with internal structures suggestive of Antoni A/B histology, and characteristic tumor extension may provide key diagnostic clues for porta hepatic schwannomas.

Hepatic Positron Emission Tomography: Applications in Metabolism, Haemodynamics and Cancer

Evaluating in vivo the metabolic rates of the human liver has been a challenge due to its unique perfusion system. Positron emission tomography (PET) represents the current gold standard for assessing non-invasively tissue metabolic rates in vivo. Here, we review the existing literature on the assessment of hepatic metabolism, haemodynamics and cancer with PET. The tracer mainly used in metabolic studies has been [¹⁸F]2-fluoro-2-deoxy-D-glucose (¹⁸F-FDG). Its application not only enables the evaluation of hepatic glucose uptake in a variety of metabolic conditions and interventions, but based on the kinetics of ¹⁸F-FDG, endogenous glucose production can also be assessed. 14(R,S)-[¹⁸F]fluoro-6-thia-Heptadecanoic acid (¹⁸F-FTHA), ¹¹C-Palmitate and ¹¹C-Acetate have also been applied for the assessment of hepatic fatty acid uptake rates (¹⁸F-FTHA and ¹¹C-Palmitate) and blood flow and oxidation (¹¹C-Acetate). Oxygen-15 labelled water (¹⁵O-H₂O) has been used for the quantification of hepatic perfusion. ¹⁸F-FDG is also the most common tracer used for hepatic cancer diagnostics, whereas ¹¹C-Acetate has also shown some promising applications in imaging liver malignancies. The modelling approaches used to analyse PET data and also the challenges in utilizing PET in the assessment of hepatic metabolism are presented.

Morphological, dynamic and functional characteristics of liver pseudolesions and benign lesions

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related deaths worldwide and one of the most common causes of death among patients with cirrhosis, developing in 1-8% of them every year, regardless of their cirrhotic stage. The radiological features of HCC are almost always sufficient for reaching the diagnosis; thus, histological confirmation is rarely needed. However, the study of cirrhotic livers remains a challenge for radiologists due to the developing of fibrous and regenerative tissue that cause the distortion of normal liver parenchyma, changing the typical appearances of benign lesions and pseudolesions, which therefore may be misinterpreted as malignancies. In addition, a correct distinction between pseudolesions and malignancy is crucial to allow appropriate targeted therapy and avoid treatment delays.The present review encompasses technical pitfalls and describes focal benign lesions and pseudolesions that may be misinterpreted as HCC in cirrhotic livers, providing the imaging features of regenerative nodules, large regenerative nodules, siderotic nodules, hepatic hemangiomas (including rapidly filling and sclerosed hemangiomas), segmental hyperplasia, arterioportal shunts, focal confluent fibrosis and focal fatty changes. Lastly, the present review explores the most promising new imaging techniques that are emerging and that could help radiologists differentiate benign lesions and pseudolesions from overt HCC.

An activated excretion-retarded tumor imaging strategy towards metabolic organs

Intraoperative fluorescence-based tumor imaging plays a crucial role in performing the oncological safe tumor resection with the advantage of differentiating tumor from normal tissues. However, the application of these fluorescence contrast agents in renal cell carcinoma (RCC) and hepatocellular carcinoma (HCC) was dramatically hammered as a result of lacking active targeting and poor retention time in tumor, which limited the Signal to Noise Ratio (SNR) and narrowed the imaging window for complicated surgery. Herein, we reported an activated excretion-retarded tumor imaging (AERTI) strategy, which could be in situ activated with MMP-2 and self-assembled on the surface of tumor cells, thereby resulting in a promoted excretion-retarded effect with an extended tumor retention time and enhanced SNR. Briefly, the AERTI strategy could selectively recognize the Integrin α_vβ₃. Afterwards, the AERTI strategy would be activated and in situ assembled into nanofibrillar structure after specifically cleaved by MMP-2 upregulated in a variety of human tumors. We demonstrated that the AERTI strategy was successfully accumulated at the tumor sites in the 786-O and HepG2 xenograft models. More importantly, the modified modular design strategy obviously enhanced the SNR of AERTI strategy in the imaging of orthotopic RCC and HCC. Taken together, the results presented here undoubtedly confirmed the design and advantage of this AERTI strategy for the imaging of tumors in metabolic organs.

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Fluorescence-based tumor imaging plays a crucial role in performing the oncological safe tumor resection.

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Self-assembled peptide possesses the advantage of active targeting and long-term retention time in tumor.

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The activated excretion-retarded tumor imaging strategy extended the tumor retention time and enhanced SNR.

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Assembly-mediated peptide probe successfully achieved the accurate identification of tumor boundaries and detection of minimal tumors (<2 mm).

Cavernous Hemangioma: A Potential Pitfall at Delayed 18F-FDG PET/CT Scan

ABSTRACT

We report the case of a 72-year-old woman who underwent neoadjuvant chemotherapy, right quadrantectomy (invasive ductal carcinoma, G3, pT2pN1pMx), and adjuvant radiotherapy. Two years later, a follow-up CT revealed a hepatic nodule of approximately 1 cm suspected for metastasis. 18F-FDG PET/CT was performed for restaging. Standard total-body 18F-FDG PET/CT acquisition showed no abnormal 18F-FDG uptake in the hepatic nodule. A delayed 18F-FDG PET/CT acquisition of upper abdomen was performed at 180 minutes postradiopharmaceutical injection and showed increased 18F-FDG uptake in the hepatic nodule. After nodule resection, the histological examination proved a cavernous hemangioma.

PET/CT Variants and Pitfalls in Liver, Biliary Tract, Gallbladder and Pancreas

A wide variety of pathological anomalies may occur in the liver, biliary system, and pancreas. It is a necessity to use many different imaging techniques in order to distinguish such varied pathologies, especially those from malignant processes. Positron Emission Tomography/Computed Tomography (PET/CT) is an imaging method that has proven its diagnostic value in oncology and can be used for different clinical purposes. Fluoro-18 fluoro-2-deoxy-D-glucose has a wide range of uses as a dominant radiopharmaceutical in routine molecular imaging, however, molecular imaging has started to play a more important role in personalized cancer treatment in recent years with new Fluoro-18 and Gallium-68 labeled tracers. Although molecular imaging has a strong diagnostic effect, the surprises and pitfalls of molecular imaging can lead us to unexpected and misleading results. Prior to PET/CT analysis and reporting, information about possible technical and physiological pitfalls, normal histological features of tissues, inflammatory pathologies, specific clinical features of the case, treatment-related complications and past treatments should be evaluated in advance to avoid misinterpretation. In this review, the physiological and pathophysiological variants as well as pitfalls encountered in PET/CT imaging of the liver, biliary tract, gallbladder, and pancreas will be examined. Other benign and malignant pathologies that have been reported to date and that have led to incorrect evaluation will be listed. It is expected that the devices, software, and artificial intelligence applications that will be developed in the near future will enable much more effective and faster imaging that will reduce the potential causes of error. However, as a result of the dynamic and evolving structure of the information obtained by molecular imaging, the inclusion of the newly developed radiopharmaceuticals in routine practice will continue to carry new potentials as well as new troubles. Although molecular imaging will be the flagship of diagnostic oncology in the 21st century, the correct analysis and interpretation by the physician will continue to form the basis of achieving optimal performance.