Efficiency and Accuracy Evaluation of Multiple Diffusion-Weighted MRI Techniques Across Different Scanners.

BACKGROUND: The choice between different diffusion-weighted imaging (DWI) techniques is difficult as each comes with tradeoffs for efficient clinical routine imaging and apparent diffusion coefficient (ADC) accuracy. PURPOSE: To quantify signal-to-noise-ratio (SNR) efficiency, ADC accuracy, artifacts, and distortions for different DWI acquisition techniques, coils, and scanners. STUDY TYPE: Phantom, in vivo intraindividual biomarker accuracy between DWI techniques and independent ratings. POPULATION/PHANTOMS: NIST diffusion phantom. 51 Patients: 40 with prostate cancer and 11 with head-and-neck cancer at 1.5 T FIELD STRENGTH/SEQUENCE: Echo planar imaging (EPI): 1.5 T and 3 T Siemens; 3 T Philips. Distortion-reducing: RESOLVE (1.5 and 3 T Siemens); Turbo Spin Echo (TSE)-SPLICE (3 T Philips). Small field-of-view (FOV): ZoomitPro (1.5 T Siemens); IRIS (3 T Philips). Head-and-neck and flexible coils. ASSESSMENT: SNR Efficiency, geometrical distortions, and susceptibility artifacts were quantified for different b-values in a phantom. ADC accuracy/agreement was quantified in phantom and for 51 patients. In vivo image quality was independently rated by four experts. STATISTICAL TESTS: QIBA methodology for accuracy: trueness, repeatability, reproducibility, Bland-Altman 95% Limits-of-Agreement (LOA) for ADC. Wilcoxon Signed-Rank and student tests on P < 0.05 level. RESULTS: The ZoomitPro small FOV sequence improved b-image efficiency by 8%-14%, reduced artifacts and observer scoring for most raters at the cost of smaller FOV compared to EPI. The TSE-SPLICE technique reduced artifacts almost completely at a 24% efficiency cost compared to EPI for b-values ≤500 sec/mm2 . Phantom ADC 95% LOA trueness were within ±0.03 × 10-3 mm2 /sec except for small FOV IRIS. The in vivo ADC agreement between techniques, however, resulted in 95% LOAs in the order of ±0.3 × 10-3 mm2 /sec with up to 0.2 × 10-3 mm2 /sec of bias. DATA CONCLUSION: ZoomitPro for Siemens and TSE SPLICE for Philips resulted in a trade-off between efficiency and artifacts. Phantom ADC quality control largely underestimated in vivo accuracy: significant ADC bias and variability was found between techniques in vivo. LEVEL OF EVIDENCE: 3 TECHNICAL EFFICACY STAGE: 2.

Is imagery distinctive in papillary renal cell carcinoma subtypes?

INTRODUCTION: The subdivision into two entities of papillary renal cell carcinoma (PRCC) was established on histological criteria. It's in fact possible to distinguish the two subtypes by the means of radiological and progressive data. The subtype 1 is associated with the favorable profile. The ultrasound and especially CT urography ensure an accurate diagnostic approach with substantial therapeutic and prognostic involvement. The aim of the study is to define the radiological features that distinguish the two subtypes of renal papillary carcinoma, and to study the radiological predictive factors of locoregional recurrence, metastases free survival and specific survival. METHODS: It's about a monocentric, retrospective study led between January 2005 and June 2017, gathering 49 cases of operated PRCC. The study concerned patients over the age of 18, who were diagnosed after anatomopathological examination of the operative specimen (enlarged nephrectomy or conservative surgery). Cases in which diagnosis was made by renal biopsy were excluded. The comparative study concerned ultrasound and CT scan data. Univariate and multivariate analysis were performed to determine factors having a prognostic value in terms of locoregional recurrence, metastases-free and specific survival. RESULTS: On the ultrasound, the subtype 1 tumors were significantly homogenous with regular contours. Tumors were globally spontaneously hypodense and hypo vascular in 97,8% of cases. Enhancement was significantly more heterogonous for subtype 2 (p=0,01). Intratumoral necrosis and adenomegalies were associated with subtype 2 (p=0,0001 and 0,005). The predictive factors of locoregional recurrence, metastases-free survival and specific survival in univariate analysis were the contours' aspect, moderate enhancement and the presence of adenomegalies. On multivariate analysis, only the irregular contours were retained for locoregional recurrence-free survival and specific survival. CONCLUSIONS: Significant differences between the PRCC subtypes were observed when studying the radiological data. Irregular contours, adenomegalies and enhancement degree seemed to predict the progression of PRCC after curative surgery.

Vasitis: An Uncommon Diagnosis Mimicking Incarcerated Inguinal Hernia.

Vasitis or inflammation of the vas deferens is a rarely described condition. Clinically, it presents with nonspecific symptoms that can be confused with other more common conditions, especially an incarcerated inguinal hernia. The diagnosis may be suggested by ultrasound or, more precisely, by computed tomography.

[Neonatal respiratory morbidity after elective cesarean section at term]. / Morbidité respiratoire néonatale après césarienne elective a terme.

BACKGROUND: Incidence of elective caesareans at term is increasing these last decades with an associated increase of neonatal respiratory morbidity. AIM: To analyse the influence of elective Caesarean delivery at term on the incidence of neonatal respiratory distress in order to propose an effective strategy of prevention. METHODS: It is an analytical study compiling all births resulting from elective Caesarean at term (gestational age ranging between 37 and 41+6 GA), reported over two years period at the Charles Nicolle hospital (Tunis-Tunisia). We compared 250 live births, without maternal risk factors, delivered by elective Caesarean to 250 births delivered by vaginal way. RESULTS: Frequency of the elective Caesarean at term was of 3.6% live births; it was mainly indicated in the presence of a cicatricial uterus. The incidence of respiratory morbidity was 6% (15/250) in the group exposed to the elective caesarean versus 1.6% (4/250 cas) in the reference group, OR=3.9; 95%CI: [1, 28-11, 99] p<0.01. Before the term of 39 GA, OR=5.22; 95%CI: [1.14-23.87] p=0.01. After 39 GA, the risk of respiratory distress decreased: OR=1.86 95%CI: [0.30, 11.35] NS. The principal etiology of respiratory distress in the exposed group was the transitory tachypnea of the newborn. CONCLUSION: Incidence of respiratory distress was higher at newborn babies born from elective Caesarean with a significant reduction in this incidence after the term of 39 GA.