Strategies to develop radiomics and machine learning models for lung cancer stage and histology prediction using small data samples.

Predictive models based on radiomics and machine-learning (ML) need large and annotated datasets for training, often difficult to collect. We designed an operative pipeline for model training to exploit data already available to the scientific community. The aim of this work was to explore the capability of radiomic features in predicting tumor histology and stage in patients with non-small cell lung cancer (NSCLC). We analyzed the radiotherapy planning thoracic CT scans of a proprietary sample of 47 subjects (L-RT) and integrated this dataset with a publicly available set of 130 patients from the MAASTRO NSCLC collection (Lung1). We implemented intra- and inter-sample cross-validation strategies (CV) for evaluating the ML predictive model performances with not so large datasets. We carried out two classification tasks: histology classification (3 classes) and overall stage classification (two classes: stage I and II). In the first task, the best performance was obtained by a Random Forest classifier, once the analysis has been restricted to stage I and II tumors of the Lung1 and L-RT merged dataset (AUC = 0.72 ± 0.11). For the overall stage classification, the best results were obtained when training on Lung1 and testing of L-RT dataset (AUC = 0.72 ± 0.04 for Random Forest and AUC = 0.84 ± 0.03 for linear-kernel Support Vector Machine). According to the classification task to be accomplished and to the heterogeneity of the available dataset(s), different CV strategies have to be explored and compared to make a robust assessment of the potential of a predictive model based on radiomics and ML.

Large-format platinum silicide microwave kinetic inductance detectors for optical to near-IR astronomy.

We have fabricated and characterized 10,000 and 20,440 pixel Microwave Kinetic Inductance Detector (MKID) arrays for the Dark-speckle Near-IR Energy-resolved Superconducting Spectrophotometer (DARKNESS) and the MKID Exoplanet Camera (MEC). These instruments are designed to sit behind adaptive optics systems with the goal of directly imaging exoplanets in a 800-1400 nm band. Previous large optical and near-IR MKID arrays were fabricated using substoichiometric titanium nitride (TiN) on a silicon substrate. These arrays, however, suffered from severe non-uniformities in the TiN critical temperature, causing resonances to shift away from their designed values and lowering usable detector yield. We have begun fabricating DARKNESS and MEC arrays using platinum silicide (PtSi) on sapphire instead of TiN. Not only do these arrays have much higher uniformity than the TiN arrays, resulting in higher pixel yields, they have demonstrated better spectral resolution than TiN MKIDs of similar design. PtSi MKIDs also do not display the hot pixel effects seen when illuminating TiN on silicon MKIDs with photons with wavelengths shorter than 1 µm.

Physics, Techniques and Review of Neuroradiological Applications of Diffusion Kurtosis Imaging (DKI).

In recent years many papers about diagnostic applications of diffusion tensor imaging (DTI) have been published. This is because DTI allows to evaluate in vivo and in a non-invasive way the process of diffusion of water molecules in biological tissues. However, the simplified description of the diffusion process assumed in DTI does not permit to completely map the complex underlying cellular components and structures, which hinder and restrict the diffusion of water molecules. These limitations can be partially overcome by means of diffusion kurtosis imaging (DKI). The aim of this paper is the description of the theory of DKI, a new topic of growing interest in radiology. DKI is a higher order diffusion model that is a straightforward extension of the DTI model. Here, we analyze the physics underlying this method, we report our MRI acquisition protocol with the preprocessing pipeline used and the DKI parametric maps obtained on a 1.5 T scanner, and we review the most relevant clinical applications of this technique in various neurological diseases.

Renal transplantation in patients with "valve bladder": is bladder augmentation necessary?

INTRODUCTION: Posterior urethral valve is a common cause of renal failure in children. This disorder often results in small bladder and low compliance, which frequently requires bladder augmentation. Herein, we report our experience in 5 children with "valve bladder" who underwent renal transplantation without preliminary bladder enlargement. MATERIALS AND METHODS: Thirteen children with valve bladder undergoing renal transplantation were considered candidates for bladder augmentation. All had oligoanuria at transplantation. In 8 children, bladder augmentation was performed before renal transplantation; in the remaining 5, the decision was postponed until after transplantation. These children underwent transplantation with a ureteral reimplant, and a suprapubic catheter was in place for 2 months. Periodically, renal function, bladder capacity, and compliance were assessed, and renal ultrasonography was performed. RESULTS: At 1-, 2-, 4-, and 6-month follow-up, the 5 children who did not undergo bladder augmentation demonstrated normal renal function, with improved bladder capacity and absence of hydronephrosis. No significant difference was evident between the 2 groups (augmented vs nonaugmented) insofar as renal function, bladder capacity, or hydronephrosis. After transplantation, bladder augmentation was not deemed necessary in any of the 5 children because of complete restoration of clinical and urodynamic parameters. CONCLUSION: Renal transplantation can be performed safely without preemptive bladder augmentation. Ureteral reimplantation is recommended, even in patients with small valve bladders. The decision about the need for bladder augmentation should be made only after normal diuresis is restored.

Arterial changes in children undergoing renal transplantation.

INTRODUCTION: Pathological changes of large arterial walls and the heart have been described in patients with chronic renal failure. The aim of the study was to verify the incidence of arterial changes among our series of pediatric patients with end-stage renal disease undergoing transplantation. PATIENTS AND METHODS: From January 2004 to December 2006, 26 patients (15 boys and 11 girls) of overall mean age of 13.12 years (range=3-27 years) underwent renal transplantation in our department. The pretransplant dialysis treatment was peritoneal in eight and hemodialysis in 18 cases. All patients were divided in two groups according to primary renal disease: group A were 18 patients with congenital urinary malformations; and group B, eight patients with acquired glomerular diseases. In each case, a sample of artery from both donor (aortic patch of kidney) and recipient (iliac patch of graft allocation) was obtained during renal transplantation. The donors were considered to be the control group. RESULTS: Light microscopy showed pathological changes in 12/26 recipient arteries: nine showed light fragmentation of the internal elastic lamina; two, more severe fragmentations; and one, fragmentation of the internal elastic lamina associated with mucopolysaccharide deposits. Pathological changes were more evident in group A than B, but the difference was not significant (P> .05). Among the donor group, 11 patients showed light fragmentation of the internal elastic lamina, but there was no significant difference with the recipients (P> .05). CONCLUSIONS: Among our group of patients, we observed only slight modifications of the arterial wall. These changes were nonspecific, similar to those in a control group of donors matched for age. A possible explanation of these findings may depend on the short time of dialysis before transplantation.

Renal embolization as an alternative to surgical nephrectomy in children.

PURPOSE: Complete renal embolization may be an alternative to surgical nephrectomy. The indications for renal embolization do not differ from those for surgical nephrectomy, but the less invasive nature of the technique is a major advantage. Few case reports are available in the pediatric age group. Our experience showed that complete renal embolization was feasible in pediatric patients with results comparable to those obtained in adults. MATERIALS AND METHODS: Twelve pediatric patients underwent 14 renal embolizations. The indications for embolization were as follows: (1) severe hypertension in 7 patients with end-stage renal failure; in these cases, a unilateral native nephrectomy was recommended prior to renal transplantation; (2) end-stage hydronephrosis in 3 patients with moderate hypertension or recurrent urinary infection; (3) nephrotic syndrome in 1 patient; or (4) ablation of an irreversibly rejected renal allograft in 1 patient. The embolization was performed under epidural anesthesia in 10 patients and under general anesthesia in 2 patients, by means of a polyvinyl alcohol injection with hemostatic gelatin powder and placement of coils. Postembolization course was followed. RESULTS: The embolization was successful in all 12 patients. In 1 patient, the procedure had to be repeated as a small accessory artery had revascularized the upper pole. In another patient, the procedure was bilateral in 2 separate sessions. In 10 patients, severe flank pain required narcotic analgesia. Two patients had fever. None had hypertension peaks. Median hospital stay was 4 days. At mean follow-up of 16 months, the results were stable. CONCLUSION: Renal embolization can avoid surgical nephrectomy also in pediatric patients. The advantages are less morbidity and shorter hospital stay. Our results in the short and medium term were equal to those of surgical removal. The procedure appeared to be safe and minimally invasive.

First paediatric experience of a new device for "non-endoscopic" periurethral injection in urinary incontinence.

The results of endoscopic treatment for urinary incontinence (ETUI) depend on the condition of the urethral mucosa and on the length of the urethra. ETUI is quite difficult to perform in female patients, and, in general, in cases of scarred urethral mucosa. A new device (Zuidex, Q-Med, Uppsala, Sweden) has recently been designed for the "non-endoscopic" treatment of urinary stress incontinence in women. Three paediatric cases are described hereunder. Three patients were treated using Zuidex: two patients (two girls aged 8 and 18) on intermittent catheterization for neurogenic bladder, and one 11-year-old girl, with epispadias, who had already undergone bladder neck reconstruction (Young-Deese). Zuidex is a special implacer for dextranomer implants. It consists of four syringes filled with dextranomer, one implacer, and four needles (25 gauges). Once the device is positioned, the four injections are performed. At the end of this procedure, four implants are symmetrically positioned at four points of the urethral wall, increasing the outlet resistance. In the follow-up phase (5-13 months), the increase in the continent period was +56, 50 and 36%; the increase in bladder capacity (leak volume point) was 40, 28 and 27% in the three patients. Although the new device for "non-endoscopic" treatment of urinary incontinence has been designed for women, the size of the implacer virtually allows its use in any paediatric patient who is above the age of six. Our early experience indicates that this new device could play an important role in the treatment of urinary incontinence in paediatric age.

Hydronephrosis due to malrotation in a pelvic ectopic kidney with vascular anomalies.

A particular case of hydronephrosis in ectopic kidney due to a malrotation and vascular anomalies in a young girl is described. The patient was previously operated for ureteropelvic junction obstruction at the age of two. Clinic and radiographic and pathologic findings are discussed and the literature is reviewed.

Renal damage in vesico-ureteric reflux.

OBJECTIVE: To detect the different extent of renal parenchymal involvement in primary vesico-ureteric reflux (VUR), and to evaluate the relationship between VUR grade, patient age and different patterns of parenchymal damage. PATIENTS AND METHODS: This blinded retrospective study included 197 consecutive children (mean age 4.26 years, range 1 month to 13 years) with primary VUR detected by voiding cysto-urethrography (VCUG), 99mTc-dimercaptosuccinic acid (DMSA; 120 MBq/1.73 m2) renal scintigraphy, with scanning for 3 h after intravenous injection. An abnormal DMSA scan was classified into three subtypes: cortical defects as a single scar (SS), multiple cortical scarring (MS) and diffuse reduced uptake with small renal size. Renal absolute uptake (AU), and split-kidney relative uptake were evaluated in refluxing and nonrefluxing renal units, and correlated with parenchymal damage and patient age. Student's t-test and the chi-square test were used for the statistical analysis. RESULTS: In all, 282 refluxing and 112 nonrefluxing units were assessed. Renal damage was detected in 188 of 282 units with VUR (67%) and in 18 of 112 (16%) contralateral nonrefluxing kidneys. The mean AU was 18.7% in kidneys with VUR and 29% in nonrefluxing units (P < 0.001). The mean (SD) AU decreased from lower to higher grades of VUR, i.e. grade 0 VUR (group A), 28.97 (9.71); grade 1-3 (group B), 21.28 (8.33); grade 4-5 (group C), 14.78 (8.02). The differences were statistically significant (A vs B, B vs C, both P < 0.001). Renal damage was differently distributed in the three groups: 69 of 109 kidneys (63%) in group C (MS prevalent), 39 of 173 (22.5%) in group B (SS prevalent) and 17 of 112 (15.2%) in group A. There was no significant difference in the distribution of renal damage subtypes in patients aged < or > 2 years (SS 19.6% vs 17.9%, MS 29.6% vs 30.1%, small size 48.2% vs 46.3%). The VUR was severe (group C) in 65% of patients aged < 2 years and in 46% aged > 2 years (chi-square, P = 0.016). CONCLUSIONS: VUR is commonly associated with renal damage. Age (< or > 2 years) did not significantly influence the kidney lesion subtype. Reduced parenchymal function (AU) progressively decreased with the severity of VUR. Focal MS, reduced size and relative uptake were significantly more common in severe VUR, leading to multifocal lesions and hypo-dysplasia. Renal scarring was present in up to 15% of contralateral nonrefluxing kidneys. Severe VUR behaved differently from lesser VUR in the renal scan parenchymal uptake.

Lower urinary tract dysfunction and disability status in patients with multiple sclerosis.

OBJECTIVE: To investigate the correlation between neurologic and urologic status in patients with multiple sclerosis (MS). MATERIALS AND METHODS: Between January 1993 and December 1995, 116 patients with MS symptoms were fully assessed neurologically and urologically with urodynamic studies. RESULTS: Urodynamic abnormalities were detected in 104 patients (89.6%). Several significant relationships between urinary tract findings and neurologic dysfunction were: (1) the relation between voiding disorder as the presenting symptom of the disease and a higher severity of bladder dysfunction; (2) the relation between reduced bladder sensation and longer duration of voiding disorders, lower detrusor uninhibited contractions threshold, and lower bladder capacity; and (3) the relation between voiding disorders and cerebellar system score. Finally, a significant inverse relationship was found between detrusor hypocontractility and neurologic status (from the Expanded Disability Status Scale, pyramidal system score, and Barthel Index). CONCLUSIONS: In this series a high incidence of patients reported voiding disorder as the presenting symptom of MS. These patients also showed a higher severity of urodynamic disorders. They should be rigorously followed up. Furthermore, our data suggest that although the most common cause of altered bladder control in MS is spinal cord pathology, involvement of cortical centers and/or peripheral neuronal lesions may occur.

[Correlation between bladder echography and urodynamic examination in patients with multiple sclerosis]. / Correlazioni tra ecografia vescicale ed esame urodinamico in pazienti affetti da sclerosi multipla.

Ultrasonography take a predominant place in the evaluation of urologic complications in SM patients. SM can cause urinary disorders according to entity and level of the primary lesion with important repercussion on the upper urinary tract. Aim of this work is to value the sensibility of ultrasonography in the identification of bladder wall abnormalities indicative of involvement of upper urinary tract, correlated with urodynamic evaluation. Since 1993 we performed 116 urological ultra sound in patients with Multiple Sclerosis. We considered pathologic bladders with wall abnormalities or with stones, considering those abnormalities as secondary to altered emptying of the bladder. 65 patients showed wall abnormalities while 51 patients had any alteration evaluated with ultrasonography. In the first group the amplitude of uninhibited detrusor contractions was 74 cmH2O, while in the second group it was 61 cm H2O: the difference was statistically significant. Furthermore the incidence of upper tract alterations was significantly higher in the first group (p = 0.005), even in absence of signs of renal failure. Thus, ultrasonography demonstrated a high sensibility in detecting bladder conditions possibly conducive to upper urinary tract deterioration.