Machine Learning and Radiomics Applications in Esophageal Cancers Using Non-Invasive Imaging Methods-A Critical Review of Literature.

Esophageal cancer (EC) is of public health significance as one of the leading causes of cancer death worldwide. Accurate staging, treatment planning and prognostication in EC patients are of vital importance. Recent advances in machine learning (ML) techniques demonstrate their potential to provide novel quantitative imaging markers in medical imaging. Radiomics approaches that could quantify medical images into high-dimensional data have been shown to improve the imaging-based classification system in characterizing the heterogeneity of primary tumors and lymph nodes in EC patients. In this review, we aim to provide a comprehensive summary of the evidence of the most recent developments in ML application in imaging pertinent to EC patient care. According to the published results, ML models evaluating treatment response and lymph node metastasis achieve reliable predictions, ranging from acceptable to outstanding in their validation groups. Patients stratified by ML models in different risk groups have a significant or borderline significant difference in survival outcomes. Prospective large multi-center studies are suggested to improve the generalizability of ML techniques with standardized imaging protocols and harmonization between different centers.

A methodology review on the incremental prognostic value of computed tomography biomarkers in addition to Framingham risk score in predicting cardiovascular disease: the use of association, discrimination and reclassification.

BACKGROUND: Computed tomography (CT) biomarkers claim to improve cardiovascular risk stratification. This review focuses on significant differences in incremental measures between adequate and inadequate reporting practise. METHODS: Studies included were those that used Framingham Risk Score as a baseline and described the incremental value of adding calcium score or CT coronary angiogram in predicting cardiovascular risk. Searches of MEDLINE, EMBASE, Web of Science and Cochrane Central were performed with no language restriction. RESULTS: Thirty five studies consisting of 206,663 patients (men = 118,114, 55.1%) were included. The baseline Framingham Risk Score included the 1998, 2002 and 2008 iterations. Selective reporting, inconsistent reference groupings and thresholds were found. Twelve studies (34.3%) had major and 23 (65.7%) had minor alterations and the respective Δ AUC were significantly different (p = 0.015). When the baseline model performed well, the Δ AUC was relatively lower with the addition of a CT biomarker (Spearman coefficient = - 0.46, p < 0.0001; n = 33; 76 pairs of data). Other factors that influenced AUC performance included exploration of data analysis, calibration, validation, multivariable and AUC documentation (all p < 0.05). Most studies (68.7%) that reported categorical NRI (n = 16; 46 pairs of data) subjectively drew strong conclusions along with other poor reporting practices. However, no significant difference in values of NRI was found between adequate and inadequate reporting. CONCLUSIONS: The widespread practice of poor reporting particularly association, discrimination, reclassification, calibration and validation undermines the claimed incremental value of CT biomarkers over the Framingham Risk Score alone. Inadequate reporting of discrimination inflates effect estimate, however, that is not necessarily the case for reclassification.

Endovascular interventional modalities for haemorrhage control in abnormal placental implantation deliveries: a systematic review and meta-analysis.

OBJECTIVES: To examine the evidence regarding the effectiveness and safety of endovascular interventional modalities for haemorrhage control in abnormal placentation deliveries. METHODS: MEDLINE, EMBASE and the Cochrane Central Register of Controlled Trials (CENTRAL) were searched from inception to July 2017. Blood loss volume was regarded as the primary endpoint. Other important results are described. Random and fixed effects models were used for the meta-analysis. RESULTS: Of 385 studies identified, 69 (1,811 patients, mean age 32.9 years, range 23-39 years) were included. Mean gestational age at delivery was 35.1 weeks (range 27-38 weeks). Of 1,395 patients who underwent endovascular intervention, 587 (42%) had placenta accreta, 254 (18%) placenta increta and 313 (22%) placenta percreta. Prophylactic balloon occlusion of the internal iliac arteries (PBOIIA) was performed in 470 patients (33.6%), of the abdominal aorta (PBOAA) in 460 patients (33%), of the uterine artery (PBOUA) in 181 patients (13%), and of the common iliac arteries (PBOCIA) in 21 patients (1.5%). Primary embolization of the UA was performed in 246 patients (18%), of the pelvic collateral arteries in 12 patients (0.9%), and of the anterior division of the IIA in 5 patients (0.3%). Follow-up ranged from 0.5 to 42 months. Endovascular intervention was associated with less blood loss than no endovascular intervention (p < 0.001) with the lowest blood loss volume in patients who underwent PBOAA (p < 0.001). PBOAA was associated with a lower rate of hysterectomy (p = 0.030). Endovascular intervention did not result in increases in operative time or hospital stay. CONCLUSIONS: Endovascular intervention is effective in controlling haemorrhage in abnormal placentation deliveries. PBOAA was associated with a lower rate of hysterectomy and less blood loss than other modalities. KEY POINTS: • Endovascular intervention in abnormal placentation deliveries is effective in reducing blood loss. • Endovascular intervention did not result in longer operative time or hospital stay. • Prophylactic balloon occlusion of the abdominal aorta is superior to other modalities.

Prospective intra-individual comparison of standard dose versus reduced-dose thoracic CT using hybrid and pure iterative reconstruction in a follow-up cohort of pulmonary nodules-Effect of detectability of pulmonary nodules with lowering dose based on nodule size, type and body mass index.

OBJECTIVES: To determine the diagnostic accuracy of lung nodule detection in thoracic CT using 2 reduced dose protocols comparing 3 available CT reconstruction algorithms (filtered back projection-FBP, adaptive statistical reconstruction-ASIR and model-based iterative reconstruction-MBIR) in a western population. MATERIALS AND METHODS: A prospective single-center study recruited 98 patients with written consent. Standard dose (STD) thoracic CT followed by 2 reduced-dose protocols using automatic tube current modulation (RD1) and fixed tube current (RD2) were performed and reconstructed with FBP, ASIR and MBIR with subsequent diagnostic accuracy analysis for nodule detection. RESULTS: 108 solid nodules, 47 subsolid nodules and 89 purely calcified nodules were analyzed. RD1 was superior to RD2 for assessment of solid nodules ≤4mm, and subsolid nodules ≤5mm (p<0.05). Deterioration of RD2 is correlated to patient's body mass index and least affected by MBIR. For solid nodules ≤4mm, MBIR area under curve (AUC) for RD1 was 0.935/0.913 and AUC for RD2 was 0.739/0.739, for rater 1/rater2 respectively. For subsolid nodules ≤5mm, MBIR AUC for RD1 was 0.971/0.986 and AUC for RD2 was 0.914/0.914, for rater 1/rater2 respectively. For calcified nodules excellent detection accuracy was maintained regardless of reconstruction algorithms with AUC >0.97 for both readers across all dose and reconstruction algorithms. CONCLUSIONS: Diagnostic performance of lung nodule is affected by nodule size, protocol, reconstruction algorithm and patient's body habitus. The protocol in this study showed that RD1 was superior to RD2 for assessment of solid nodules ≤4mm, and subsolid nodules ≤5mm and deterioration of RD2 is related to patient's body mass index.

Intra-patient comparison of reduced-dose model-based iterative reconstruction with standard-dose adaptive statistical iterative reconstruction in the CT diagnosis and follow-up of urolithiasis.

OBJECTIVES: To evaluate the accuracy of reduced-dose CT scans reconstructed using a new generation of model-based iterative reconstruction (MBIR) in the imaging of urinary tract stone disease, compared with a standard-dose CT using 30% adaptive statistical iterative reconstruction. METHODS: This single-institution prospective study recruited 125 patients presenting either with acute renal colic or for follow-up of known urinary tract stones. They underwent two immediately consecutive scans, one at standard dose settings and one at the lowest dose (highest noise index) the scanner would allow. The reduced-dose scans were reconstructed using both ASIR 30% and MBIR algorithms and reviewed independently by two radiologists. Objective and subjective image quality measures as well as diagnostic data were obtained. RESULTS: The reduced-dose MBIR scan was 100% concordant with the reference standard for the assessment of ureteric stones. It was extremely accurate at identifying calculi of 3 mm and above. The algorithm allowed a dose reduction of 58% without any loss of scan quality. CONCLUSIONS: A reduced-dose CT scan using MBIR is accurate in acute imaging for renal colic symptoms and for urolithiasis follow-up and allows a significant reduction in dose. KEY POINTS: • MBIR allows reduced CT dose with similar diagnostic accuracy • MBIR outperforms ASIR when used for the reconstruction of reduced-dose scans • MBIR can be used to accurately assess stones 3 mm and above.

Sarcoidosis--the greatest mimic.

Little is known regarding the exact pathogenesis of sarcoidosis, but it is widely recognized that it affects multiple organs. The presentation and imaging features can be nonspecific, and this is the reason why it is a great mimic of other diseases. Diagnosis of sarcoidosis is often prompted initially by clinical suspicion. Imaging plays a crucial role in both detection and monitoring of disease process. This review is a case-based systemic approach looking at various systemic manifestation of the disease presenting real clinical encounters using various imaging modalities.

Active haemorrhage of a renal allograft detected on portable ultrasound.

Function of a renal allograft relies on the integrity of its vascular anatomy. Renal biochemistry, ultrasound and percutaneous biopsy are used in combination to determine allograft function. Biopsy is not without risk, and in this case study we demonstrate a rare but a potentially life-threatening complication of renal allograft biopsy.

A staged management of prolonged chylothorax in a patient with yellow nail syndrome.

Spontaneous chylothorax remains an unusual condition with diverse aetiologies and non-unified management strategies. Owing to the rarity of the condition, the evidence of management remains from case reports and limited retrospective studies. This case represents a difficult-to-manage chylothorax secondary to yellow nail syndrome with initial failure of both surgical and conservative treatment methods. Pleurovenous shunting represents a surgical management approach allowing the patient to live with and control an ongoing chyle leak.

A difficult case of fever of unknown origin.

A 57-year-old holidaymaker in Madeira was airlifted to England with a 4-week history of fever, limb weakness and hypophonia. Having undergone a range of investigations during his hospital admission abroad - including ultrasound, CT, echocardiogram and lumbar puncture - the patient arrived without any explanatory diagnosis. At presentation, the only investigatory positives were raised blood inflammatory markers and a, previously unidentified, 'old left frontal infarct' found on head CT. A broad infective and immunological screen proved negative, raising the possibility of vasculitis. Finally, the presence of subacute cerebral and renal infarcts identified on MRI and CT in combination with a negative antineutrophil cytoplasmic antibodies (ANCA) test and distinctive muscle biopsy features confirmed the clinical suspicion of polyarteritis nodosa. An immunosuppressive regime of glucocorticoid therapy and cyclophosphamide were initiated with immediate significant clinical improvement.