Feasibility of Robot-Assisted Ultrasound Imaging with Force Feedback for Assessment of Thyroid Diseases.

Medical ultrasound is extensively used to define tissue textures and to characterize lesions, and it is the modality of choice for detection and follow-up assessment of thyroid diseases. Classical medical ultrasound procedures are performed manually by an occupational operator with a hand-held ultrasound probe. These procedures require high physical and cognitive burden and yield clinical results that are highly operator-dependent, therefore frequently diminishing trust in ultrasound imaging data accuracy in repetitive assessment. A robotic ultrasound procedure, on the other hand, is an emerging paradigm integrating a robotic arm with an ultrasound probe. It achieves an automated or semi-automated ultrasound scanning by controlling the scanning trajectory, region of interest, and the contact force. Therefore, the scanning becomes more informative and comparable in subsequent examinations over a long-time span. In this work, we present a technique for allowing operators to reproduce reliably comparable ultrasound images with the combination of predefined trajectory execution and real-time force feedback control. The platform utilized features a 7-axis robotic arm capable of 6-DoF force-torque sensing and a linear-array ultrasound probe. The measured forces and torques affecting the probe are used to adaptively modify the predefined trajectory during autonomously performed examinations and probe-phantom interaction force accuracy is evaluated. In parallel, by processing and combining ultrasound B-Mode images with probe spatial information, structural features can be extracted from the scanning volume through a 3D scan. The validation was performed on a tissue-mimicking phantom containing thyroid features, and we successfully demonstrated high image registration accuracy between multiple trials.

Reflex Testing for Germline BRCA1, BRCA2, PALB2, and ATM Mutations in Pancreatic Cancer: Mutation Prevalence and Clinical Outcomes From Two Canadian Research Registries.

PURPOSE: We investigated the translational value of reflex testing for germline mutations in four homology-directed DNA repair predisposition genes (BRCA1, BRCA2, PALB2, and ATM) in consecutive patients with pancreatic adenocarcinoma. METHODS: One hundred fifty patients with French-Canadian (FC) ancestry were evaluated for founder mutations, and 114 patients were subsequently assessed by full gene sequencing and multiplex ligation-dependent probe amplification for nonfounder mutations. Two hundred thirty-six patients unselected for ancestry were also assessed for mutations by full gene sequencing. RESULTS: The FC founder mutation prevalence among the 150 patients was 5.3% (95% CI, 2.6% to 10.3%), and the nonfounder mutation prevalence across the four genes among the 114 patients tested was 2.6% (95% CI, 0.6% to 7.8%). In the case series unselected for ancestry, 10.0% (95% CI, 2.7% to 26.4%) of patients reporting Ashkenazi Jewish (AJ) ancestry carried an AJ founder mutation, with no nonfounder mutations identified. The mutation prevalence among patients without FC/AJ ancestry was 4.9% (95% CI, 2.6% to 8.8%). Mutations were more frequent in patients diagnosed at ≤ 50 years of age (P = .03) and in patients with either two or more first- or second-degree relatives with pancreas, breast, ovarian or prostate cancer, or one such relative and a second primary of one of these cancer types (P < .001). BRCA1, BRCA2, and PALB2 carriers with late-stage (III or IV) disease had an overall survival advantage (P = .049), particularly if treated with platinum-based chemotherapies (P = .030). CONCLUSION: Considering these results, we recommend reflex founder mutation testing of patients with FC/AJ ancestry and full gene sequencing of patients who are ≤ 50 years or meet the identified family history criteria. Reflex testing of all incident patients for these four genes may become justified as full gene sequencing costs decline.

Optimizing cine MRI for uterine peristalsis: a comparison of three different single shot fast spin echo techniques.

PURPOSE: To determine the optimal single shot fast spin echo (SSFSE) technique by varying interval between image acquisitions for cine MRI of uterine peristalsis. MATERIALS AND METHODS: MRI was performed in 13 premenopausal women (4 normal and 9 with benign pelvic pathology) in various phases of their menstrual cycle. Midsagittal uterus was scanned using a multiphasic SSFSE technique at 2-, 3-, and 4-s intervals over 2 min. Three readers independently and randomly evaluated for peristaltic frequency/2 min, longitudinal direction and intensity of peristalsis in three imaging parameters. Contrast-to-noise ratios (CNRs) were also obtained. RESULTS: Peristaltic frequency for the 2, 3, and 4 s was 2.2 ± 2.3, 3.3 ± 1.5, and 3.6 ± 1.3 waves/2 min, respectively. It increased by 1.5 (95% confidence interval [CI]: 0.31-2.64) waves/2 min with 4 s compared with 2 s. Direction was detected for the 2, 3, and 4 s in 5/13(38%), 9/13(69%) and 12/13(92%) women. Compared with 2 s, intensity of peristalsis in endometrial movement (P = 0.04), signal change of the JZ (P = 0.03), and spread into outer myometrium (P = 0.02), CNRendometrium-JZ by 57% (P < 0.001), and CNRouter myometrium-JZ by 45% (P < 0.01) increased with 4 s. CONCLUSION: Cine MRI with SSFSE sequence for uterine peristaltism is best performed using a 4-s scan interval.

Arterial spin labeling MR imaging for characterisation of renal masses in patients with impaired renal function: initial experience.

OBJECTIVES: To retrospectively evaluate the feasibility of arterial spin labeling (ASL) magnetic resonance imaging (MRI) for the assessment of vascularity of renal masses in patients with impaired renal function. METHODS: Between May 2007 and November 2008, 11/67 consecutive patients referred for MRI evaluation of a renal mass underwent unenhanced ASL-MRI due to moderate-to-severe chronic or acute renal failure. Mean blood flow in vascularised and non-vascularised lesions and the relation between blood flow and final diagnosis of malignancy were correlated with a 2-sided homogeneous variance t-test and the Fisher Exact Test, respectively. A p value <0.05 was considered statistically significant. RESULTS: Seventeen renal lesions were evaluated in 11 patients (8 male; mean age = 70 years) (range 57-86). The median eGFR was 24 mL/min/1.73 m(2) (range 7-39). The average blood flow of 11 renal masses interpreted as ASL-positive (134 +/- 85.7 mL/100 g/min) was higher than that of 6 renal masses interpreted as ASL-negative (20.5 +/- 8.1 mL/100 g/min)(p = 0.015). ASL-positivity correlated with malignancy (n = 3) or epithelial atypia (n = 1) at histopathology or progression at follow up (n = 7). CONCLUSIONS: ASL detection of vascularity in renal masses in patients with impaired renal function is feasible and seems to indicate neoplasia although the technique requires further evaluation. KEY POINTS: Arterial spin labeling may help to characterise renal masses in patients with renal failure Detection of blood flow on ASL in a renal mass supports the presence of a neoplasm Renal masses with high blood-flow levels on ASL seem to progress rapidly.