Non-invasive diagnostic imaging of colorectal liver metastases

Colorectal cancer is one of the few malignant tumors in which synchronous or metachronous liver metastases [colorectal liver metastases (CRLMs)] may be treated with surgery. It has been demonstrated that resection of CRLMs improves the long-term prognosis. On the other hand, patients with un-resectable CRLMs may benefit from chemotherapy alone or in addition to liver- directed therapies. The choice of the most appropriate therapeutic management of CRLMs depends mostly on the diagnostic imaging. Nowadays, multiple non-invasive imaging modalities are available and those have a pivotal role in the workup of patients with CRLMs. Although extensive research has been performed with regards to the diagnostic performance of ultrasonography, computed tomography, positron emission tomography and magnetic resonance for the detection of CRLMs, the optimal imaging strategies for staging and follow up are still to be established. This largely due to the progressive technological and pharmacological advances which are constantly improving the accuracy of each imaging modality. This review describes the non-invasive imaging approaches of CRLMs reporting the technical features, the clinical indications, the advantages and the potential limitations of each modality, as well as including some information on the development of new imaging modalities, the role of new contrast media and the feasibility of using parametric image analysis as diagnostic marker of presence of CRLMs

Multi-messenger observations of a binary neutron star merger

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

Ruolo degli aspetti morfologici e metabolici nella diagnosi differenziale tra patologie benigne e maligne della milza

E' stato valutato il ruolo di dispositivi tomografici TC e PET/TC di nuova generazione nella diagnosi differenziale delle patologie spleniche benigne e maligne, usando l’esame cito/istologico come standard di riferimento. Nello specifico, lo scopo dello studio è stato di: 1) definire gli aspetti della TC e PET/TC capaci di differenziare le patologie spleniche benigne dalle maligne; 2) valutare se la PET/TC aggiunge informazioni addizionali ai risultati della TC

Evaluation of metabolic response with 18FFDG PET-CT in patients with advanced or recurrent thymic epithelial tumors

Background: Patients with advanced or recurrent thymic epithelial tumors (TETs) often need several consecutive lines of chemotherapy. The aim of this retrospective monocentric study was to test whether 18F-Fluorodeoxyglucose positron emission tomography-computed tomography (18F-FDG PET-CT) is able to monitor standard chemotherapy efficacy in those patients and whether metabolic response correlates with morphovolumetric response as assessed by Response Evaluation Criteria in Solid Tumor (RECIST). Methods: We evaluated 27 consecutive patients with advanced (16 patients) or recurrent (11 patients) TETs. All patients underwent 18F-FDG PET-CT before and after at least 3 cycles of chemotherapy. Maximum standardized uptake value (SUVmax) of all detected lesions was recorded and the most 18F-FDG avid lesion in each patient was selected for determination of percentage change of SUVmax (ΔSUVmax) in pre- and post-treatment scans. Tumor response was assessed by contrastenhanced computed tomography (CE-CT) using RECIST criteria. Receiver operating characteristic (ROC) curve analysis was performed to define the optimal threshold of ΔSUVmax discriminating responders from non-responders. Results: Metabolic response expressed as ΔSUVmax was significantly correlated with morphovolumetric response (Spearman’s rank correlation, r = 0.64, p = 0.001). ROC curve analysis showed that a ΔSUVmax value of -25% could discriminate responders from non-responders with a sensitivity of 88% and a specificity of 80%. Conversely, basal SUVmax values were not predictive of morphovolumetric tumor response. Conclusions: Our findings indicate that metabolic response assessed by 18F-FDG PET-CT, through evaluation of ΔSUVmax, may allow identification of responders and non-responders thus guiding adaptation of therapy in patients with advanced or recurrent TETs

Colorectal cancer and 18FDG-PET/CT: What about adding the T to the N parameter in loco-regional staging?

AIM: To evaluate whether FDG-positron emission tomography (PET)/computed tomography (CT) may be an accurate technique in the assessment of the T stage in patients with colorectal cancer

Intestinal amyloidosis: Two cases with different patterns of clinical and imaging presentation

The involvement of the small bowel in systemic forms of amyloidosis may be diffuse or very rarely focal. Some cases of focal amyloidomas of the duodenum and jejunum without extraintestinal manifestations have been reported. The focal amyloidomas consisted of extensive amyloid infiltration of the entire intestinal wall thickness. Radiological barium studies, ultrasound and computed tomography (CT) patterns of diffuse small bowel amyloidosis have been described: the signs are non-specific and may include small-bowel dilatation, symmetric bowel wall thickening, mesenteric infiltration, and mesenteric adenopathy. No data are available about the positron emission tomography (PET)/CT and magnetic resonance imaging (MRI) patterns of intestinal amyloidosis. We report two cases of small bowel amyloidosis: the former characterized by focal deposition of amyloid proteins exclusively within blood vessel walls of the terminal ileum, the latter characterized by diffuse intestinal involvement observed on MRI and PET/CT studies

Tomographic imaging of the spleen: the role of morphological and metabolic features in differentiating benign from malignant diseases

To evaluate the tomographic features in differentiating benign from malignant splenic diseases, 54 patients with a cytohistological examination and a contrast-enhanced multidetector computed tomography (ce-MDCT) and/or positron emission tomography/computed tomography (PET/CT) were retrospectively selected. Significant associations were observed between ce-MDCT Pattern 3 (focal hyperdense lesion) and Pattern 4 (infarcts/cysts) as well as PET/CT Pattern 3 (focal photopenia/diffuse uptake<liver) and benign pathologies, and between ce-MDCT Pattern 1 (splenomegaly without focal lesions) and Pattern 2 (focal hypodense lesion) as well as PET/CT Pattern 1 (diffuse uptake≥liver) and Pattern 2 (focal increased uptake) and malignant diseases. No significant association between benign or malignant diseases and spleen volumes and maximum standardized uptake value (SUVmax) as well as lesion characteristics was observed. The metabolic data do not improve the performance of morphological patterns

BALANCING RADIATION AND CONTRAST MEDIA DOSE IN SINGLE-PASS CONTRAST-ENHANCED MULTI-DETECTOR CT: PROSPECTIVE EVALUATION OF IMAGE QUALITY

RATIONALE and OBJECTIVE: As both contrast and radiation dose affect the quality of CT images, a constant image quality in abdominal contrast-enhanced multi-detector CT (CE-MDCT) could be obtained balancing radiation and contrast media dose according to the age of the patients. MATERIALS AND METHODS: Seventy-two (38M;34F; aged 20-83 years) patients underwent a single-pass abdominal CE-MDCT. Patients were divided into three different age-groups: A(20-44 years); B (45-65 years); C (> 65 years). For each group, a different Noise Index (NI) and contrast media dose (370 mgI/mL) was selected as follows: A (NI=15; 2.5 mL/kg); B (NI =12.5; 2 mL/kg); C (NI=10; 1.5 mL/kg). Radiation exposure was reported as Dose Length Product (DLP) in mGy*cm. For quantitative analysis, Signal-to-Noise (SNR) and Contrast-to-Noise (CNR) ratios were calculated for both the liver (L) and the abdominal aorta (A). Statistical analysis was performed with a one-way ANOVA. Standard imaging criteria were used for qualitative analysis. RESULTS: Whereas peak hepatic enhancement was 152±16, 128±12 and 101±14 HU (p <0 .001) for Group A, B and C, respectively, no significant differences were observed in the corresponding SNRL with 9.2±1.4, 9.1±1.2 and 9.2±3. Radiation (mGy*cm) and contrast media dose (mL) administered were 476±147 and 155±27 for Group A, 926±291 and 130±16 for Group B and 1981± 451 and 106±15 for Group C, respectively (p < 0.001). None of the studies was graded as poor or inadequate by both readers and the PABAK ranged between 0.48 and 0.93 for all but one criteria. CONCLUSIONS: A constant image quality in CE-MDCT can be obtained balancing radiation and contrast media dose administered to patients of different age