New advances in radiomics of gastrointestinal stromal tumors

Gastrointestinal stromal tumors(GISTs)are uncommon neoplasms of the gastrointestinal tract with peculiar clinical,genetic,and imaging characteristics.Preoperative knowledge of risk stratification and mutational status is crucial to guide the appropriate patients’treatment.Predicting the clinical behavior and biological aggressiveness of GISTs based on conventional computed tomography(CT)and magnetic resonance imaging(MRI)evaluation is challenging,unless the lesions have already metastasized at the time of diagnosis.Radiomics is emerging as a promising tool for the quantification of lesion heterogeneity on radiological images,extracting additional data that cannot be assessed by visual analysis.Radiomics applications have been explored for the differential diagnosis of GISTs from other gastrointestinal neoplasms,risk stratification and prediction of prognosis after surgical resection,and evaluation of mutational status in GISTs.The published researches on GISTs radiomics have obtained excellent performance of derived radiomics models on CT and MRI.However,lack of standardization and differences in study methodology challenge the application of radiomics in clinical practice.The purpose of this review is to describe the new advances of radiomics applied to CT and MRI for the evaluation of gastrointestinal stromal tumors,discuss the potential clinical applications that may impact patients’management,report limitations of current radiomics studies,and future directions.

Coronary artery calcium score on low-dose computed tomography for lung cancer screening

AIM: To evaluate the feasibility of coronary artery calcium score(CACS) on low-dose non-gated chest CT(ngCCT).METHODS: Sixty consecutive individuals(30 males; 73 ± 7 years) scheduled for risk stratification by means of unenhanced ECG-triggered cardiac computed to-mography(gCCT) underwent additional unenhanced ngCCT. All CT scans were performed on a 64-slice CT scanner(Somatom Sensation 64 Cardiac, Siemens, Germany). CACS was calculated using conventional methods/scores(Volume, Mass, Agatston) as previ-ously described in literature. The CACS value obtained were compared. The Mayo Clinic classification was used to stratify cardiovascular risk based on Agatston CACS. Differences and correlations between the two methods were compared. A P-value < 0.05 was considered sig-nificant.RESULTS: Mean CACS values were significantly higher for gCCT as compared to ngCCT(Volume: 418 ± 747 vs 332 ± 597; Mass: 89 ± 151 vs 78 ± 141; Agatston: 481 ± 854 vs 428 ± 776; P < 0.05). The correlation between the two values was always very high(Volume: r = 0.95; Mass: r = 0.97; Agatston: r = 0.98). Of the 6 patients with 0 Agatston score on gCCT, 2(33%) showed an Agatston score > 0 in the ngCCT. Of the 3 patients with 1-10 Agatston score on gCCT, 1(33%) showed an Agatston score of 0 in the ngCCT. Overall, 23(38%) patients were reclassified in a different car-diovascular risk category, mostly(18/23; 78%) shifting to a lower risk in the ngCCT. The estimated radiation dose was significantly higher for gCCT(DLP 115.8 ± 50.7 vs 83.8 ± 16.3; Effective dose 1.6 ± 0.7 mSv vs 1.2 ± 0.2 mSv; P < 0.01).CONCLUSION: CACS assessment is feasible on ngCCT; the variability of CACS values and the associated re-stratification of patients in cardiovascular risk groups should be taken into account.