Staging and response assessment of melanoma is a challenging radiological task as the tumor entity is characterized by atypical metastatic phenotypes and response patterns. Radiologists should scrutinize diagnostic images for unusual metastatic sites, including, e.g., gastrointestinal, endobronchial, or splenic metastases. Routine imaging modalities must include body CT or PET/CT staging and brain MRI. Response assessment is complicated by pseudoprogression and dissociated response, which radiologists must identify and communicate with the treating physicians. Criteria-based reporting with immune-adapted response criteria, such as iRECIST, should be used. The abundant use of checkpoint inhibitor therapy should make radiologists aware of immune-related adverse events, which must be detected early. In addition, imaging professionals must carefully identify potential side effects that mimic progression, in particular sarcoid-like reactions with newly developed mediastinal and hilar lymphadenopathy, as this will ensure that progressive disease is not overcalled. Additionally, radiologists should be aware of the emerging field of intratumoral immunotherapy, which can result in local inflammatory changes at injection sites that may also mimic progression. For this, a dedicated adaptation of the response criteria may be applied with itRECIST.

Indeterminate lesions on prostate-specific membrane antigen (PSMA)-PET are challenging to address. We aimed to develop, implement, and evaluate a multidisciplinary consensus algorithm that integrates existing interpretation systems with multimodality imaging and clinicopathological information for interpreting indeterminate bone and lymph node lesions on PSMA-PET. This was a retrospective single-center study on a prospectively implemented algorithm. We included all consecutive prostate cancer patients whose PSMA-PET findings for indeterminate bone lesions or lymph nodes were discussed at a multidisciplinary tumor board (MDT) in 2024–2025. An algorithm determining the level of suspicion for metastasis was developed in a multidisciplinary fashion, incorporating lesion location, conventional imaging features, PSMA-PET characteristics, and clinicopathological information. The application of the algorithm and outcomes were documented, compared against a composite reference standard. Comparisons were made with PSMA-RADS and PROMISE V2 PSMA-expression scores. 81 patients (median age 68, interquartile range 64–75) were included. Algorithm results were benign (48.1

ABSTRACT:The mucosal-associated lymphoid tissue (MALT)-International Prognostic Index (IPI) is widely applied to estimate outcomes in patients with extranodal marginal zone lymphoma (EMZL) of MALT. Although it was developed in the context of the IELSG-19 trial exclusively in patients treated with chlorambucil, rituximab, or their combination, it is commonly used across virtually all disease settings. However, its applicability beyond contexts resembling the IELSG-19 trial remains debated, and several studies have proposed modifications to improve prognostic precision in EMZL. Here, we retrospectively analyzed 498 patients with newly diagnosed EMZL at the Medical University of Vienna with the dual objective of evaluating the prognostic performance of the MALT-IPI across clinical subgroups, and to assess whether incorporation of autoimmunity could refine risk stratification. Stratification by the MALT-IPI revealed significantly longer progression-free survival (PFS) and overall survival (OS) in patients who were low-risk compared with intermediate- and high-risk groups (P< .001) in unselected patients. However, in subgroup analyses, its discriminatory capacity was restricted to patients with extragastric disease, particularly patients with EMZL of the ocular adnexa or the parotid gland or intestinal EMZL, as well as those receiving systemic therapy. On the contrary, patients with gastric EMZL or those managed with Helicobacter pylori eradication, local therapy, or watch-and-wait approaches did not derive consistent prognostic separation. Incorporation of autoimmunity identified a small subgroup with inferior PFS and OS, but provided limited incremental prognostic power beyond the established index in most patients. Our results support context-specific applicability of the MALT-IPI, and highlight autoimmunity as a prognostically relevant factor in a small cohort of patients.

INTRODUCTION:Focal dose intensification strategies targeting the dominant intra-prostatic lesion (DIL) improve outcomes of patients with prostate cancer. The purpose was to determine whether the 6-month multiparametric (mp)MRI response of the DIL is associated with post-treatment prostate-specific antigen (PSA) kinetics after MRI linear accelerator (LINAC) guided stereotactic body radiotherapy (SBRT) with focal dose intensification. METHODS:Retrospective, single-center study including 72 patients with localized prostate cancer treated with MRI-LINAC SBRT with focal dose intensification and without androgen deprivation therapy. Patients were followed up at 6 months after SBRT with mpMRI and PSA. mpMRI complete response (CR) was defined as no residual lesion on diffusion-weighted imaging and dynamic contrast-enhanced MRI. This was correlated with PSA responses including PSA reduction (%), PSA reduction ≥ 50.0% (PSA50), and PSA ≤ 1.0 ng/mL. RESULTS:mpMRI CR was achieved in 37 patients (51.4%) at 6 months. Patients with mpMRI CR had greater PSA reduction (81.8% vs 66.1%, p < 0.001), and more commonly had PSA50 (100.0% vs 82.9%, p = 0.010) and PSA ≤ 1.0 ng/mL (45.9% vs 11.4%, p = 0.001) compared to those without mpMRI CR. In 10 patients without 6-month mpMRI CR but had further MRI follow-up (median 13 months), DILs either further decreased in size (30.0%) or resolved (70.0%). CONCLUSION:Initial 6-month mpMRI response correlates with PSA kinetics, which is associated with important clinical outcomes. mpMRI can be used for post-SBRT evaluation to gauge local tumor response of the DIL, where most recurrences occur.

PURPOSE OF THE REPORT:To determine the prevalence, etiology, and clinical significance of incidental focal small bowel FDG uptake in patients undergoing PET/CT for staging of non-small bowel cancers. MATERIAL AND METHODS:Retrospective review of consecutive FDG PET/CT examinations obtained for cancer staging with incidental focal small bowel radiotracer uptake was performed. Exclusion criteria included known small bowel pathology or insufficient reference standard. Imaging findings assessed included lesion location, number, CT correlate, SUV max , and presence of metastases outside the bowel. Clinical data included age, sex, cancer clinical setting, origin, and stage. Focal small bowel FDG uptake etiology (benign vs. metastatic) was determined by composite reference standard (histopathology, clinical, and imaging follow-up). Statistical analyses included Wilcoxon rank-sum test, Pearson's χ 2 test, Fisher exact test, and ROC curve analyses. RESULTS:In a review of 147,516 PET/CT examinations, incidental focal small bowel FDG uptake was rare, with a prevalence of 0.1% (88/147,516). Most cases were metastatic, 60.2% (53/88), most commonly spread from lymphoma [32.1% (17/53)] and melanoma [30.2% (16/53)]. Metastatic lesions were evenly distributed throughout the ileum [47.2% (25/53)] and jejunum [39.6% (21/53)]. Metastatic focal small bowel FDG uptake was associated with presence of other sites of distant metastases, higher SUV max , and presence of a CT correlate ( P <0.01). CONCLUSIONS:Incidental focal small bowel FDG uptake is rare. Most small bowel hypermetabolic foci are metastatic and are predominantly encountered with melanoma and lymphoma. Multiple imaging and clinical factors helped differentiate between benign and metastatic focal small bowel FDG uptake.

To assess the performance of 68Ga-PSMA PET/CT in detecting biochemically recurrent prostate cancer and evaluate associations of PET imaging findings with alterations on genomic profiling. 68Ga-PSMA PET/CT scans of 603 prostate cancer patients with biochemical recurrence or persistently elevated PSA and without known metastatic disease were retrospectively included (mean PSA 1.0 ng/mL; range, 0.08-5). All scans were analysed for presence of recurrence by two experienced nuclear medicine physicians independently; discrepancies were resolved by an additional expert reader. A subset of patients (n = 239) had undergone tumour genetic profiling using the Memorial Sloan Kettering-Integrated Mutation Profiling of Actionable Cancer Targets (MSK-IMPACT) sequencing assay. PET positivity and positive predictive value, inter-reader agreement, as well as associations between patient characteristics, location of recurrence, time to PET confirmed biochemical recurrence (PCBR), SUVmax, and most frequent gene alterations were investigated. The overall recurrence detection rate of 68Ga-PSMA PET/CT was 59.2

BACKGROUND:To evaluate whether quantitative craniospinal MRI assessment of baseline tumor burden provides prognostic value in patients with recurrent, previously irradiated medulloblastoma undergoing MEMMAT (Metronomic Antiangiogenic) therapy. METHODS:We analyzed craniospinal MRI of 40 patients with recurrent, previously irradiated medulloblastoma enrolled in the MEMMAT trial (April 1, 2014, and March 31, 2021). Ependymal, leptomeningeal, and local relapse lesions were retrospectively manually segmented on T1-contrast-enhanced (T1CE) and diffusion-weighted imaging (DWI) at baseline and follow-up (best response). Lesion count and volume were quantified. Bland-Altman analyses and intraclass correlation coefficients (ICC) assessed inter-sequence agreement., logistic regression evaluated associations between baseline tumor burden and progressive disease. RESULTS:Patients achieving Complete Response (n = 6/40) showed mean monthly decreases of - 12.7% in T1CE lesion count and - 12.9% in volume. Partial Response patients (n = 9/40) showed similar declines (-10.3% and - 13.0%). Stable Disease patients (n = 5/40) demonstrated minimal decreases (-0.8% and - 2.3%). Progressive Disease patients (n = 16/40) showed increases of 33.7% in lesion count and 56.2% in volume. Logistic regression indicated trends toward higher baseline tumor burden predicting PD (volume OR 1.18, p = 0.08; lesion count OR 1.05, p = 0.075). Agreement between T1CE and DWI was limited (ICC 0.35 for lesion count, 0.47 for volume), with 23% of patients misclassified using either modality alone. Survival analyses demonstrated significantly shorter overall survival in patients with baseline lesion volumes ≥ 5.5 ml (log-rank p = 0.003), while a similar association for progression-free survival did not reach statistical significance (p = 0.053). CONCLUSIONS:Combined intracranial and intraspinal T1CE and intracranial DWI assessment improves response evaluation. Exploratory analyses suggested that higher baseline tumor burden may be associated with progression, although the observed associations were of borderline statistical significance and require validation in larger cohorts.

Background Magnetic field inhomogeneities are challenging for ultrahigh-field (UHF) MRI, and may affect segmentation algorithm performance. We therefore investigated the impact of different segmentation techniques on radiomic features extracted from UHF MRI of the brain. Materials and Methods We analyzed 21 MP2RAGE datasets with 0.63 mm3 isotropic resolution obtained at 7 Tesla. Radiomic features (histogram, texture, and shape) from the cerebral gray and white matter, basal ganglia, ventricles, cerebellum, and brainstem were extracted using three segmentation techniques: the deep-learning algorithm Cerebrum-7T; the Freesurfer-v7 algorithm; and the Nighres algorithm. Principal components (PCs) were calculated for histogram and texture features, and intraclass correlation coefficients (ICC) were used to compare radiomic feature values and PCs to those obtained with a reference standard including human expert correction. Results For histogram PCs, exemplary median ICCs for Cerebrum-7T, Freesurfer-v7, and Nighres were 0.99, 0.42, and 0.11 for the gray matter; and 0.84, 0.25, and 0.43 for basal ganglia. For texture PCs, median ICCs for Cerebrum-7T, Freesurfer-v7, and Nighres were 0.95, 0.21, and 0.15 for the gray matter; and 0.70, 0.36, and 0.023 for basal ganglia. For shape features, median ICCs for Cerebrum-7T, FreeSurfer-v7, and Nighres were 0.99, 0.91, and 0.36 for the gray matter; and 0.89, 0.90, and 0.13 for basal ganglia. Conclusions Radiomic features on UHF MRI of the brain show substantial variability depending on the segmentation method. Segmentation tools tailored for the use with UHF data, such as the deep-learning algorithm Cerebrum-7T, may be needed for adequate reproducibility of radiomic features at 7 Tesla.

An increasing number of patients with prostate cancer (PCa) undergo assessment with magnetic resonance imaging (MRI) and prostate-specific membrane antigen positron emission tomography/computed tomography (PSMA-PET/CT). This offers comprehensive multimodality staging but can lead to discrepancies. The objective was to assess the rates and types of discordance between MRI and PSMA-PET/CT for primary PCa assessment. Consecutive men diagnosed with intermediate and high-risk PCa who underwent MRI and PSMA-PET/CT in 2021–2023 were retrospectively included. MRI and PSMA-PET/CT were interpreted using PI-RADS v2.1 and PRIMARY scores. Discordances between the two imaging modalities were categorized as “minor” (larger or additional lesion seen on one modality) or “major” (positive on only one modality or different index lesions between MRI and PSMA-PET/CT) and reconciled using radical prostatectomy or biopsy specimens. Three hundred and nine men (median age 69 years, interquartile range (IQR) 64–75) were included. Most had Gleason Grade Group ≥ 3 PCa (70.9

Imaging is used for lymphoma detection, Ann Arbor/Lugano staging, and treatment response assessment. [18F]FDG PET/CT should be used for most lymphomas, including Hodgkin lymphoma, aggressive/high-grade Non-Hodgkin lymphomas (NHL) such as diffuse large B-cell lymphoma, and many indolent/low-grade NHLs such as follicular lymphoma. Apart from these routinely FDG-avid lymphomas, some indolent NHLs, such as marginal zone lymphoma, are variably FDG-avid; here, [18F]FDG PET/CT is an alternative to contrast-enhanced CT at baseline and may be used for treatment response assessment if the lymphoma was FDG-avid at baseline. Only small lymphocytic lymphoma/chronic lymphocytic leukemia (SLL/CLL) should exclusively undergo CT at baseline and follow-up unless transformation to high-grade lymphoma is suspected. While [18F]FDG PET/CT is sufficient to rule out bone marrow involvement in Hodgkin lymphoma, biopsy may be needed in other lymphomas. The 5-point (Deauville) score for [18F]FDG PET that uses the liver and blood pool uptake as references should be used to assess treatment response in all FDG-avid lymphomas; post-treatment FDG uptake ≤ liver uptake is considered complete response. In all other lymphomas, CT should be used to determine changes in lesion size; for complete response, resolution of all extranodal manifestations, and for lymph nodes, long-axis decrease to ≤ 1.5 cm are required.

To develop a tool for the clinical hybrid imaging workflow which combines morphologic and functional measurements. And to quantify the number of clicks saved per positron emission tomography/computed tomography (PET/CT) interpretation. A tool was developed where a volume of interest (VOI) is automatically created around line distance measurements. VOI statistics for both PET and CT component, and line distances are generated and displayed. Usage data for the first two months after introduction of the tool was analyzed. Eleven radiologists and nuclear medicine physicians used the tool in 364 PET/CTs. In 19

Prostate-specific membrane antigen (PSMA)-PET/CT has become integral to management of prostate cancer; however, PSMA-avid rib lesions pose a diagnostic challenge. This study investigated clinicopathological and imaging findings that predict metastatic etiology of PSMA-avid rib lesions. Consecutive patients with prostate cancer that underwent PET/CT with [18F]F-DCFPyL in 2021–2023 for newly diagnosed intermediate-/high-risk prostate cancer or recurrent/metastatic disease and had PSMA-avid rib lesions were included. Imaging findings assessed were: lesion number, PSMA expression (maximum standard uptake value (SUVmax), miPSMA score), CT features (sclerotic, lucent, fracture, no correlate), other sites of metastases, and primary tumor findings. A composite reference standard for rib lesion etiology (metastatic vs non-metastatic) based on histopathology, serial imaging, and clinical assessment was used. One hundred and seventy-five men (median 71 years, IQR 65–77) with PSMA-avid rib lesions were included; 47/175 (26.9

To explore pragmatic approaches integrating MRI and PSMA-PET/CT for evaluating extraprostatic extension (EPE) of prostate cancer (PCa). Consecutive patients with newly-diagnosed PCa that underwent multiparametric MRI and PSMA-PET/CT, followed by radical prostatectomy in 2021–2024 were included. Imaging parameters assessed on both modalities were: size, length of capsular contact (LCC), Likert scales (MRI EPE grade/PSMA Likert scale), PI-RADS/PRIMARY scores, and SUVmax. Three pragmatic integrated approaches were tested: (1) Integration of Likert scales (positive if either or both MRI and PSMA-PET/CT were positive); (2) P score (framework combining PI-RADS + PRIMARY); and (3) combining MRI morphological information with PSMA-PET/CT functional information (upgrading suspicion of lesions with LCC below cutoff if SUVmax>12). Diagnostic performance was tested with receiver operating characteristic (ROC) curves and compared using DeLong and McNemar tests. 67 men (median age, 66 years) with EPE in 76.1

Supplementary Data containing the statistical analysis plan, Supplemental Figures 1-6 and Supplemental Tables 1 and 2

Liquid biopsy helps detect cells and cell-derived metabolites, proteins, nucleic acids, and vesicles that are shed into body fluids by tumors. This diagnostic test requires only approximately 10 mL of blood or urine. It has received considerable attention as a minimally invasive tool for whole-body tumor interrogation for use in patients with cancer. It poses an attractive and potentially cost-effective alternative to invasive tissue sampling through tissue biopsies, especially serial assessments, such as for treatment response evaluation and mutations that occur during cancer treatment. Cell-free and circulating tumor DNA are the most frequently tested liquid biopsy analytes, and have shown promise for cancer screening, assessment of residual disease after treatment, and clinical outcome prediction and prognostication. Whereas liquid biopsy is less sensitive than imaging in early tumor stages, it is more specific and may help detect treatment response earlier than the Response Evaluation Criteria in Solid Tumors, or RECIST. Aimed primarily at radiologists, this review article provides an update on recent developments in the use of liquid biopsy, including findings from landmark clinical trials and U.S. regulatory approvals as companion diagnostic tests for clinical use, particularly in four malignancies: lymphoma, breast cancer, prostate cancer, and melanoma. Finally, current challenges for the clinical implementation of liquid biopsy are discussed.

The chemotherapy regimen capecitabine/temozolomide (CAPTEM) is routinely used in neuroendocrine tumors (NET), with antitumor activity particularly demonstrated in pancreatic or high-grade neuroendocrine neoplasms (NEN). However, different dosing regimens are used, and the optimal schedule remains to be defined. This single-center retrospective analysis assessed the efficacy and safety of CAPTEM in patients with NEN using a schedule starting both compounds simultaneously (temozolomide on days 1-5 and capecitabine on days 1-14 of a 28-day cycle) rather than sequentially. The primary parameters of interest were response rates, progression-free survival (PFS), and toxicities following this treatment regimen, hereinafter referred to as TEMCAP. The study population comprised 40 patients, half of whom (n = 20) had pancreatic NEN, and 9 patients (22.5%) had pulmonary or thymic NETs. The most common histology was NET G3 (n = 15, 37.5%), and 8 patients (20.0%) had a neuroendocrine carcinoma (NEC). Most patients (77.5%) had at least one prior systemic therapy, and 16 patients (40.0%) prior chemotherapy. The median number of TEMCAP cycles was 6 (range 1-16). Median PFS for the highly heterogeneous population was 13.3 months, while the median overall survival was 31.9 months. In total, 14/36 patients (38.9%) exhibited a partial response, and the disease control rate was 75.0%. The safety profile of TEMCAP (at a below-target mean temozolomide dose of 118.85 mg/m(2)) in our cohort was remarkably good with no toxicities of grade 3 or 4. Taken together, the results of this analysis further support the use of temozolomide/capecitabine in NEN and prompt further assessment of our modified TEMCAP schedule.