Complete and partial spontaneous regression of metastases of lung cancer in a patient: Serial CT and 18F-fluodeoxyglucose PET/CT findings.

Spontaneous regression of cancer is a rare biological phenomenon and the mechanisms underlying it are poorly understood. There have been few reports of temporal changes in morphology and metabolism associated with spontaneous regression. Here, we report an 80-year-old man who presented with right upper quadrant pain. He was diagnosed with stage IVA lung cancer, but without treatment, rib metastasis disappeared 4 months after the diagnosis. Although mediastinal lymph node metastasis regressed partially it began to grow 10 months after the diagnosis. In this case, complete and partial spontaneous tumor regressions were observed in the patient, allowing for a comparison of morphological and metabolic changes during each occurrence by serial computed tomography (CT) and 18F-fluodeoxyglucose positron emission tomography with computed tomography (FDG-PET/CT). We observed that the rib metastasis with high FDG uptake on initial PET/CT was composed of cancer cells as well as intratumoral immune cells, whereas recurrent mediastinal lymph node metastasis with high FDG uptake on follow-up PET/CT was composed of cancer cells with few immune cells. Our findings suggest that hypermetabolism within the rib metastasis on initial PET/CT reflected immune activation, whereas hypermetabolism within the mediastinal lymph node on follow-up PET/CT reflected tumor activation.

Pulmonary metastases from pancreatic cancer have different clinico-radiological features compared with those from colorectal cancer.

BACKGROUND: Although pulmonary metastasectomy is a commonly-performed procedure, data are lacking on the feasibility and oncological efficacy of removal of pulmonary metastases from pancreatic cancer. In this study, we retrospectively compared features of pulmonary metastases from pancreatic cancer versus colorectal cancer (CRC, patients with CRC being common candidates for pulmonary metastasectomy) and outcomes of removing such metastases, with our aim being to identify specific features of the former. METHODS: Data on removal of 182 pulmonary metastases (29 from pancreatic and 153 from CRC) performed from January 2013 to April 2024 were included in this analysis. Radio-pathological findings were compared between these groups. The study cohort comprised 139 pulmonary metastasectomies in 119 patients (24 with pancreatic cancer and 95 with CRC) in whom R0 resection was achieved and follow-up data were available. RESULTS: Atypical radiological findings of pulmonary metastases, including polygonal-shape (P < 0.001), spiculae (P < 0.001), air bronchogram (P = 0.012), peripheral ground-glass opacities (P < 0.001), and pleural tags (P < 0.001) were present more frequently in metastases from pancreatic cancer than from CRC. Furthermore, pleural lavage cytology was more frequently positive in pulmonary metastases from pancreatic cancer than in those from CRC (P < 0.001). Disease-free survival was significantly shorter after the removal of metastases from pancreatic than from CRC (P < 0.001). CONCLUSIONS: Some pulmonary metastases from pancreatic cancer have atypical radiological features. Surgical interventions for these may enable diagnosis. The prognosis is significantly poorer after removing metastases from pancreatic cancer than from CRC. The therapeutic significance of our findings requires further investigation.

Prediction of Efficacy for Atezolizumab/Bevacizumab in Unresectable Hepatocellular Carcinoma with Hepatobiliary-Phase Gadolinium Ethoxybenzyl-Diethylenetriaminepentaacetic Acid MRI.

BACKGROUND: This study aimed to examine whether the coefficient of variation (CV) in the hepatobiliary-phase (HBP) of Gd-EOB-DTPA-MRI could be an independent predictive factor for tumor progression. METHODS: Patients who underwent Gd-EOB-DTPA-MRI before Atezolizumab/bevacizumab therapy at six affiliated institutions between 2018 and 2022 were included. CV for each patient was calculated as the mean value for up to five tumors larger than 10 mm, and CV of the whole tumor was calculated using LIFEx software. The tumor response was evaluated within 6-10 weeks. The primary endpoint was to investigate the predictive factors, including CV, related to tumor progression using logistic regression analysis. The secondary endpoints were tumor response rate and progression-free survival (PFS) based on CV. RESULTS: Of the 46 enrolled patients, 13 (28.3%) underwent early progressive disease. Multivariate analysis revealed that a high CV (≥0.22) was an independent predictive factor for tumor progression (p = 0.043). Patients with a high CV had significantly frequent PD than those with a low CV (43.5 vs. 13.0%, p = 0.047). Patients with a high CV tended to have shorter PFS than those with a low CV (3.5 vs. 6.7 months, p = 0.071). CONCLUSION: Quantitative analysis using CV in the HBP of Gd-EOB-DTPA-MRI may be useful for predicting tumor progression for atezolizumab/bevacizumab therapy.

Effects of Short-Term Lenvatinib Administration Prior to Transarterial Chemoembolization for Hepatocellular Carcinoma.

AIM: Transarterial chemoembolization (TACE) combined with lenvatinib, employing a 4-day lenvatinib administration followed by TACE without an interval (short-term LEN-TACE), was performed for hepatocellular carcinoma (HCC). The aim was to assess tumor hemodynamics following the 4-day lenvatinib and to evaluate the treatment outcomes after the short-term LEN-TACE. METHODS: 25 unresectable HCC patients received this combined therapy. Lenvatinib (4-12 mg) was administrated for 4 days prior to TACE. Perfusion CT scans were obtained before and after the lenvatinib administration. Either cTACE (76%) or DEB-TACE (24%) were performed. RESULTS: intra-tumor blood flow significantly decreased after the 4-day lenvatinib (p < 0.05). The TACE procedure was successful with no severe adverse events in all patients. The overall complete response (CR) rate was 75% (cTACE 84%, DEB-TACE 40%). The lipiodol-washout ratio between 1 week and 4 months after cTACE correlated with the arterial flow reduction ratio by lenvatinib prior to TACE (r = -0.55). The 12-month progression-free survival (PFS) rate was 75.0%. CONCLUSIONS: The short-term LEN-TACE is feasible and safe, demonstrating promising outcomes with a high CR ratio, contributing to lipiodol retention in the tumor after cTACE, and extended PFS. To confirm the advantages of this treatment protocol, a prospective clinical trial is mandatory.

Pictorial Review of Pleural Disease: Multimodality Imaging and Differential Diagnosis.

The pleura is a thin, smooth, soft-tissue structure that lines the pleural cavity and separates the lungs from the chest wall, consisting of the visceral and parietal pleurae and physiologic pleural fluid. There is a broad spectrum of normal variations and abnormalities in the pleura, including pneumothorax, pleural effusion, and pleural thickening. Pneumothorax is associated with pulmonary diseases and is caused by iatrogenic or traumatic factors. Chest radiography and US help detect pneumothorax with various signs, and CT can also help assess the causes. Pleural effusion occurs in a wide spectrum of diseases, such as heart failure, cirrhosis, asbestos-related diseases, infections, chylothorax, and malignancies. Chest US allows detection of a small pleural effusion and evaluation of echogenicity or septa in pleural effusion. Pleural thickening may manifest as unilateral or bilateral and as focal, multifocal, or diffuse. Various diseases can demonstrate pleural thickening, such as asbestos-related diseases, neoplasms, and systemic diseases. CT, MRI, and fluorodeoxyglucose (FDG) PET/CT can help differentiate between benign and malignant lesions. Knowledge of these features can aid radiologists in suggesting diagnoses and recommending further examinations with other imaging modalities. The authors provide a comprehensive review of the clinical and multimodality imaging findings of pleural diseases and their differential diagnoses. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

Multimodality Imaging of Primary Hepatic Lymphoma: A Case Report and a Literature Review.

Primary hepatic lymphoma (PHL) is a rare form of non-Hodgkin lymphoma primarily affecting the liver. We present a case of an 84-year-old man diagnosed with PHL, incidentally detected during abdominal ultrasonography. The ultrasonography showed a hypoechoic nodule. When examined by CEUS, the nodule showed hyperenhancement in the arterial phase and hypoenhancement in the portal and late phases. Conversely, CECT demonstrated hypoenhancement through all the phases. The patient declined a tumor biopsy and opted for follow-up care. Ten months later, the lobular mass had increased from 15 mm to 65 mm, presenting as hypoechogenic and demonstrating the "vessel-penetrating sign" on color Doppler imaging. CEUS revealed reticulated enhancement, indicating intratumoral vessels. The mass displayed hypoattenuation on plain CT, hypointensity in T1-weighted images, and hyperintensity in T2-weighted images and exhibited significant restriction in diffusion-weighted images. Both CECT and contrast-enhanced MRI exhibited hypoenhancement. The patient underwent a partial hepatic segmentectomy, and the mass was pathologically diagnosed as a diffuse large B-cell lymphoma. Subsequent postoperative radiological examinations revealed no other lesions, confirming the diagnosis of PHL. Our report highlights specific ultrasonographic signs of PHL observed from an early stage and presents a review of the relevant literature.

Hepatobiliary-phase gadolinium ethoxybenzyl-diethylenetriaminepentaacetic acid MRI for pretreatment prediction of efficacy-to-standard-therapies based on Barcelona Clinic Liver Cancer algorithm: an up-to-date review.

Recent advances in systemic therapy have had major impacts on treatment strategies for hepatocellular carcinoma (HCC). The 2022 Barcelona Clinic Liver Cancer (BCLC) guidelines incorporate a new section on clinical decision-making for personalized medicine, although the first treatment suggested by the BCLC guidelines is based on solid scientific evidence. More than ever before, the appropriate treatment strategy must be selected prior to the initiation of therapy for HCC. Gadolinium ethoxybenzyl-diethylenetriaminepentaacetic acid magnetic resonance imaging (Gd-EOB-DTPA-MRI) is essential for liver imaging and the hepatobiliary phase (HBP) of EOB-MRI reflects the expression of organic anion transporting polypeptide (OATP) transporters. Molecules associated with OATP expression are relevant in the molecular classification of HCC subclasses, and EOB-MRI is becoming increasingly important with advances in the molecular and genetic understanding of HCC. In this review, we describe imaging findings for the pretreatment prediction of response to standard therapies for HCC based on the BCLC algorithm using the HBP of EOB-MRI, with specific attention to the molecular background of OATPs. A more complete understanding of these findings will help radiologists suggest appropriate treatments and clinical follow-ups and could lead to the development of more personalized treatment strategies in the future. CLINICAL RELEVANCE STATEMENT: In the coming era of personalized medicine, HBP of EOB-MRI reflecting molecular and pathological factors could play a predictive role in the therapeutic efficacy of HCC and contribute to treatment selection. KEY POINTS: • Imaging features of hepatobiliary phase predict treatment efficacy prior to therapy and contribute to treatment choice. • Wnt/ß-catenin activation associated with organic anion transporting polypeptide expression is involved in the tumor immune microenvironment and chemo-responsiveness. • Peritumoral hypointensity of hepatobiliary phase reflecting microvascular invasion affects the therapeutic efficacy of locoregional to systemic therapy.

Liver Cancer Vascularity Driven by Extracellular Matrix Stiffness: Implications for Imaging Research.

BACKGROUND: Extracellular matrix stiffness represents a barrier to effective local and systemic drug delivery. Increasing stiffness disrupts newly formed vessel architecture and integrity, leading to tumor-like vasculature. The resulting vascular phenotypes are manifested through different cross-sectional imaging features. Contrast-enhanced studies can help elucidate the interplay between liver tumor stiffness and different vascular phenotypes. PURPOSE: This study aims to correlate extracellular matrix stiffness, dynamic contrast-enhanced computed tomography, and dynamic contrast-enhancement ultrasound imaging features of 2 rat hepatocellular carcinoma tumor models. METHODS AND MATERIALS: Buffalo-McA-RH7777 and Sprague Dawley (SD)-N1S1 tumor models were used to evaluate tumor stiffness by 2-dimensional shear wave elastography, along with tumor perfusion by dynamic contrast-enhanced ultrasonography and contrast-enhanced computed tomography. Atomic force microscopy was used to calculate tumor stiffness at a submicron scale. Computer-aided image analyses were performed to evaluate tumor necrosis, as well as the percentage, distribution, and thickness of CD34+ blood vessels. RESULTS: Distinct tissue signatures between models were observed according to the distribution of the stiffness values by 2-dimensional shear wave elastography and atomic force microscopy ( P < 0.05). Higher stiffness values were attributed to SD-N1S1 tumors, also associated with a scant microvascular network ( P ≤ 0.001). Opposite results were observed in the Buffalo-McA-RH7777 model, exhibiting lower stiffness values and richer tumor vasculature with predominantly peripheral distribution ( P = 0.03). Consistent with these findings, tumor enhancement was significantly greater in the Buffalo-McA-RH7777 tumor model than in the SD-N1S1 on both dynamic contrast-enhanced ultrasonography and contrast-enhanced computed tomography ( P < 0.005). A statistically significant positive correlation was observed between tumor perfusion on dynamic contrast-enhanced ultrasonography and contrast-enhanced computed tomography in terms of the total area under the curve and % microvessel tumor coverage ( P < 0.05). CONCLUSIONS: The stiffness signatures translated into different tumor vascular phenotypes. Two-dimensional shear wave elastography and dynamic contrast-enhanced ultrasonography adequately depicted different stromal patterns, which resulted in unique imaging perfusion parameters with significantly greater contrast enhancement observed in softer tumors.

Salvage Locoregional Therapy Following Progression After Radiotherapy for Hepatocellular Carcinoma Is Associated with Improved Outcomes.

PURPOSE: To evaluate the impact of salvage locoregional therapy (salvage-LT) on survival of hepatocellular carcinoma (HCC) patients presenting with intrahepatic tumor progression following radiotherapy. METHODS: This single-institution retrospective analysis included consecutive HCC patients having intrahepatic tumor progression following radiotherapy during 2015-2019. Overall survival (OS) was calculated from the date of intrahepatic tumor progression after initial radiotherapy by using the Kaplan-Meier method. Log-rank tests and Cox regression models were used for univariable and multivariable analyses. An inverse probability weighting was used to estimate treatment effect of salvage-LT considering confounding factors. RESULTS: A total of 123 patients (mean age ± SD, 70 years ± 10; 97 men) were evaluated. Among those, 35 patients underwent 59 sessions of salvage-LT, including transarterial embolization/chemoembolization (n = 33), ablation (n = 11), selective internal radiotherapy (n = 7), and external beam radiotherapy (n = 8). At a median follow-up of 15.1 months (range, 3.4-54.5 months), the median OS was 23.3 months in patients who received salvage-LT and 6.6 months who did not. At multivariate analysis, ECOG performance status, Child-Pugh class, albumin-bilirubin grade, extrahepatic disease, and lack of salvage-LT were independent predictors of worse OS. After inverse probability weighting, salvage-LT was associated with a survival benefit of 8.9 months (95% CI: 1.1, 16.7 months; p = 0.03). CONCLUSIONS: Salvage locoregional therapy is associated with increased survival in HCC patients suffering from intrahepatic tumor progression following initial radiotherapy.

Development of liposomal contrast agent with high iodine concentration and minimal effect on renal function.

Purpose: The use of contrast media is essential to achieve high accuracy in diagnostic imaging. Iodine contrast media, one of these contrast media, has nephrotoxicity as a side effect. Therefore, the development of iodine contrast media that can reduce nephrotoxicity is expected. Since liposomes are generally adjustable in size (100-300 nm) and are not filtered by the renal glomerulus, we hypothesized that iodine contrast media could be encapsulated in liposomes and administered to avoid the nephrotoxicity of iodine contrast media. The aim of this study is to develop an iomeprol-containing liposome (IPL) agent with high iodine concentration and to investigate the effect of intravenous administration of IPL on renal function in a rat model with chronic kidney injury. Materials and methods: IPLs were prepared by encapsulating an iomeprol (400mgI/mL) solution in liposomes by a kneading method using a rotation-revolution mixer. Radiodensities of iomeprol and IPL were measured. IPL or iopamidol at normal dose (0.74 g I/kg) or high dose (3.7 g I/kg) was administered to healthy and 5/6-nephrectomized rats (n = 3-6). Serum creatinine (sCr) and histopathological change of tubular epithelial cells were evaluated after injection. Results: The iodine concentration of IPL was 220.7 mgI/mL, equivalent to 55.2% of the iodine concentration of iomeprol. The CT values of IPL was 4731.6 ± 53.2 HU, 59.04% that of iomeprol. The ratios of change in sCr in 5/6-nephrectomized rats that received high-dose iopamidol were 0.73, which were significantly higher than that in 5/6-nephrectomized rats that received high-dose IPL (-0.03) (p = 0.006). Change in foamy degeneration of tubular epithelial cells was confirmed in 5/6-nephrectomized rats that received high-dose iopamidol than that in the sham control group and healthy rats that received normal dose iopamiron (p = 0.016, p = 0.032, respectively). Foamy degeneration of tubular epitherial cells was rarely observed in the IPL injection group. Conclusions: We developed new liposomal contrast agents that have high iodine concentration and minimal effect on renal function.