In this work we present measurements of permeability, effective porosity and tortuosity on a variety of rock samples using NMR/MRI of thermal and laser-polarized gas. Permeability and effective porosity are measured simultaneously using MRI to monitor the inflow of laser-polarized xenon into the rock core. Tortuosity is determined from measurements of the time-dependent diffusion coefficient us...

BACKGROUND AND PURPOSE Dissection is an increasingly recognized cause of ischemic stroke, which occurs spontaneously or after trauma, in relatively young patients. We hypothesized that there might be a predisposing factor weakening the vascular wall and that arterial tortuosity might be higher in patients with dissection. METHODS We consecutively enrolled cervical artery dissection (CerAD) pa...

PURPOSE. An algorithm and a computer program for the automatic grading of corneal nerve tortuosity are proposed and evaluated. METHODS. Thirty images of the corneal subbasal nerve plexus with different grades of tortuosity were acquired with a scanning laser confocal microscope in normal and pathologic subjects. Nerves were automatically traced with an algorithm previously developed, and a tort...

BACKGROUND AND AIM We conducted a prospective study to investigate the possible relationship between the tortuosity of coronary arteries (TCA) and carotid intima-media thickness (CIMT), and also compare TCA to retinal artery tortuosity. METHODS One hundred and five participants with nonsignificant coronary plaque or normal coronary angiogram were included. To determine subclinical atheroscler...

BACKGROUND Hemifacial spasm (HFS) is a disabling neurological condition. Vascular tortuosity in HFS patients has not been quantified objectively and its relationship with hypertension and posterior fossa volume (PF) is unknown. In a case control magnetic resonance imaging and angiographic (MRI/A) study, we quantified and compared the vascular tortuosity in HFS and controls, and evaluated its re...

OBJECTIVES To validate the accuracy of ROPtool software in measuring retinal vascular width and tortuosity in a large image set compared with expert diagnoses. METHODS Tortuosity and dilation indexes generated by ROPtool were compared with 3 expert consensus grades of normal, pre-plus, or plus disease for 368 quadrants in 92 RetCam (Clarity Medical Systems, Pleasanton, California) fundus imag...

The mechanisms giving rise to vein tortuosity, which is often associated with varicosis, are poorly understood. Recent works suggest that significant biological changes in the wall of varicose veins may precede the mechanical aspects of the disease. To test the hypothesis of tortuosity being a consequence of these changes, a Finite Element model was developed based on previous experimental work...

Coronary tortuosity is a phenomenon often encountered by cardiologists performing coronary angiography. The aetiology and clinical importance of coronary tortuosity are still unclear. Coronary tortuosity without fixed atherosclerotic stenosis in patients with angina pectoris and an abnormal exercise stress test has never been described in the literature.This article describes three cases of pat...

Retinopathy of Prematurity (ROP) is an infant disease characterized by increased dilation and tortuosity of the retinal blood vessels. Automatic tortuosity evaluation from retinal digital images is very useful to facilitate an ophthalmologist in the ROP screening and to prevent childhood blindness. This paper proposes a method to automatically classify the image into tortuous and non-tortuous. ...