We conducted a systematic literature review on the use of [18F]FDG PET/MRI for staging/restaging rectal cancer patients with PubMed, Scopus, and Web of Science, based on the PRISMA criteria. Three authors screened all titles and abstracts and examined the full texts of all the identified relevant articles. Studies containing aggregated or duplicated data, review articles, case reports, editorials, and letters were excluded. Ten reports met the inclusion criteria. Four studies examined T staging and one focused on local recurrences after surgery; the reported sensitivity (94–100%), specificity (73–94%), and accuracy (92–100%) varied only slightly from one study to another. The sensitivity, specificity, and accuracy of [18F]FDG PET/MRI for N staging were 90–93%, 92–94%, and 42–92%. [18F]FDG PET/MRI detected malignant nodes better than MRI, resulting in treatment change. For M staging, [18F]FDG PET/MRI outperformed [18F]FDG PET/CT and CT in detecting liver metastases, whereas it performed worse for lung metastases. The results of this review suggest that [18F]FDG PET/MRI should be used for rectal cancer restaging after chemoradiotherapy and to select patients for rectum-sparing approaches thanks to its accuracy in T and N staging. For M staging, it should be associated at least with a chest CT scan to rule out lung metastases.

AIM: To examine the role of [18F]FDG PET/CT for assessing response to immunotherapy in patients with some solid tumors. METHODS: Data recorded in a multicenter (n = 17), retrospective database between March and November 2021 were analyzed. The sample included patients with a confirmed diagnosis of a solid tumor who underwent serial [18F]FDG PET/CT (before and after one or more cycles of immunotherapy), who were >18 years of age, and had a follow-up of at least 12 months after their first PET/CT scan. Patients enrolled in clinical trials or without a confirmed diagnosis of cancer were excluded. The authors classified cases as having a complete or partial metabolic response to immunotherapy, or stable or progressive metabolic disease, based on a visual and semiquantitative analysis according to the EORTC criteria. Clinical response to immunotherapy was assessed at much the same time points as the serial PET scans, and both the obtained responses were compared. RESULTS: The study concerned 311 patients (median age: 67; range: 31–89 years) in all. The most common neoplasm was lung cancer (56.9%), followed by malignant melanoma (32.5%). Nivolumab was administered in 46.3%, and pembrolizumab in 40.5% of patients. Baseline PET and a first PET scan performed at a median 3 months after starting immunotherapy were available for all 311 patients, while subsequent PET scans were obtained after a median 6, 12, 16, and 21 months for 199 (64%), 102 (33%), 46 (15%), and 23 (7%) patients, respectively. Clinical response to therapy was recorded at around the same time points after starting immunotherapy for 252 (81%), 173 (56%), 85 (27%), 40 (13%), and 22 (7%) patients, respectively. After a median 18 (1–137) months, 113 (36.3%) patients had died. On Kaplan–Meier analysis, metabolic responders on the first two serial PET scans showed a better prognosis than non-responders, while clinical response became prognostically informative from the second assessment after starting immunotherapy onwards. CONCLUSIONS: [18F]FDG PET/CT could have a role in the assessment of response to immunotherapy in patients with some solid tumors. It can provide prognostic information and thus contribute to a patient’s appropriate treatment. Prospective randomized controlled trials are mandatory.

Background: The aim of our study was to investigate the correlation among T2-weighted (T2w) images, apparent diffusion coefficient (ADC) maps, ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET) images, histogram analysis and the pathological response in locally advanced rectal cancer (LARC) after preoperative chemoradiotherapy (pCRT). Methods: Patients with LARC were prospectively enrolled between February 2015 and August 2018 and underwent PET/magnetic resonance imaging (MRI). MRI included T2w and diffusion-weighted imaging (DWI)-sequences. ADC maps and PET images were matched to the T2w images. Voxel-based standardized uptake values (SUVs,) ADC and T2w-signal-intensity values were collected from the volumes of interest (VOIs) and mean, skewness and kurtosis were calculated. Spearman’s correlation coefficient was applied to evaluate the correlation among the variables and tumor regression grade (TRG), T stage, N stage and fibrosis. Results: Twenty-two patients with biopsy-proven LARC in the low or mid rectum were enrolled [17 males, mean age was 69 years (range 49–85 years)]. Seven patients experienced complete regression (TRG1). A significant positive correlation was found between SUV mean values (ρ = 0.480; p = 0.037) and TRG. No other significant correlations were found. Conclusions: Histogram analysis of SUV values is a predictor of TRG in LARC.

Dural-based lymphomas are rare extranodal non-Hodgkin lymphomas that span from indolent primary dural entities, most commonly the extranodal marginal zone (mucosa-associated lymphoid tissue) lymphoma, to aggressive variants that are primary or represent secondary involvement from systemic lymphoma. They overlap radiologically with benign meningiomas, dural metastases, and immune-mediated pachymeningitis, creating a risk of anchoring bias, delayed diagnosis, and unnecessarily extensive resections when limited tissue sampling would be sufficient for diagnosis. We conducted a structured narrative review to synthesize the epidemiology, clinico-pathological classification, imaging phenotypes, and management principles of dural lymphomatous disease. This study will especially focus on primary dural lymphoma (PDL) with additional discussion of secondary dural involvement. Emphasis is placed on the clinical value of a multiparametric diagnostic approach that integrates computed tomography contrast-enhanced magnetic resonance imaging with functional techniques, and fluorodeoxyglucose positron emission tomography/computed tomography for systemic staging and for distinguishing truly localized primary dural lymphoma from secondary involvement. Potential diagnostic pitfalls related to somatostatin receptor–based tracer uptake will also be discussed. We introduced a pragmatic operational framework based on four clinico-biological clusters, translated into a step-by-step decision algorithm that prioritizes timely biopsy and comprehensive hematologic staging to guide surgical strategy. Given the absence of dedicated, multidisciplinary guidance for dural-based lymphomas, this algorithm is intended as a reproducible foundation for consensus recommendations and future multicenter validation.

Background: Bone scintigraphy with technetium-labeled tracers has become a cornerstone in diagnosing transthyretin cardiac amyloidosis (ATTR-CM). While visual grading systems like the Perugini Score are widely used, they lack sensitivity for monitoring therapeutic response. Quantitative single-photon emission computed tomography (SPECT)/computed tomography (CT) offers potential for objective assessment of myocardial tracer uptake and disease activity. Methods: We retrospectively analyzed 25 wild-type ATTR-CM patients who underwent sequential 99mTc-HMDP whole-body scintigraphy and thoracic SPECT/CT before and after tafamidis therapy. SPECT images were reconstructed quantitatively, and myocardial volumes were manually segmented on fused SPECT/CT images. Standardized uptake values (SUVmean, SUVmax, SUVpeak) were extracted and normalized to a reference vertebral volume. Nonparametric tests were used for paired comparisons and correlations with the Perugini Score. Results: All myocardial SUV parameters (SUVmean, SUVmax, SUVpeak) decreased significantly after tafamidis (Wilcoxon signed-rank, two-sided P < 0.0001 for all), while vertebral SUVmean remained stable ( P = 0.5539). Myocardial-to-bone SUV ratios also decreased significantly. At baseline, SUVpeak showed a moderate positive association with the Perugini Score (Kendall’s τ = 0.476, P = 0.0045); a monotonic increasing trend across categories was confirmed (Jonckheere–Terpstra z = 2.93, two-sided P = 0.0034; Kruskal–Wallis H = 7.75, P = 0.0207). Effect sizes for paired changes (Hodges–Lehmann and rank-biserial r ) indicated large and concordant within-patient reductions for SUVmax and SUVpeak. Conclusion: Quantitative SPECT/CT using SUV-based metrics provides a reproducible and sensitive method for assessing tafamidis response in ATTR-CM. Compared with existing approaches, our method – based on SUVpeak and bone normalization – offers robustness and clinical relevance, supporting its integration into routine practice.