Strain analysis using feature tracking cardiac magnetic resonance (FT-CMR) in the assessment of myocardial viability in chronic ischemic patients.

The purpose of this study is to test the capability of a commercially available feature tracking-cardiac magnetic resonance (FT-CMR) strain analysis software module in differentiating between viable and non-viable myocardium in chronic ischemic patients. Thirty chronic ischemic patients and 10 healthy volunteers were enrolled. Cine images were used for peak circumferential and radial strains quantification using dedicated FT-CMR software. Global strain was compared between patients and controls. In patients, segmental strain was compared in viable and non-viable myocardium determined by late gadolinium enhancement (LGE); and in segments with wall abnormalities. Among 480 myocardial segments analyzed in patients, 76 segments were non-viable on LGE. The mean left ventricular ejection fraction (LVEF) of the patients (87% males, mean age 55 ± 12 years) was 40 ± 12% vs. 61 ± 5% for the controls (80% males, mean age 39 ± 11 years). Peak global circumferential strain (GCS) and global radial strain (GRS) were significantly impaired in patients compared to controls (-13.89 ± 4.12% vs. -19.84 ± 1.47%), p < 0.001 and (23.11 ± 6.59% vs. 31.72 ± 5.52%), p = 0.001. Segmental circumferential strain (SCS) and segmental radial strain (SRS) were significantly impaired in non-viable compared to viable segments (-9.47 ± 7.26% vs. -14.72 ± 7.5%), p < 0.001 and (15.67 ± 12.11% vs. 24.51 ± 16.22%), p < 0.001. Cut-off points of -9.36% for the SCS (AUC = 0.7, 95% CI = 0.63-0.77) and 19.5% for the SRS (AUC = 0.67, 95%CI = 0.61-0.73) were attained above which the segment is considered viable.SCS was able to discriminate between normokinetic, hypokinetic and akinetic segments (mean = 27.6 ± 17.13%, 18.66 ± 12.88% and 15.24 ± 10.70% respectively, p < 0.001). Circumferential and radial segmental strain analysis by FT-CMR was able to discriminate between viable and non-viable segments of the myocardium defined by LGE and between normokinetic, hypokinetic and akinetic segments, using routinely acquired cine images, and thus can provide a more objective metric for risk stratification in chronic ischemic patients.

Phase-contrast and three-dimensional driven equilibrium (3D-DRIVE) sequences in the assessment of paediatric obstructive hydrocephalus.

BACKGROUND: Recently, most cases of hydrocephalus are related to obstruction. Accurate localization of the site of obstruction is crucial in determination of the treatment strategy. PURPOSE: To describe the phase-contrast and 3D-DRIVE findings in cases of obstructive hydrocephalus in paediatric patients and to determine their functional and anatomical correlates. MATERIAL AND METHODS: Brain MRIs of 25 patients (2 months to 11 years) with obstructive hydrocephalus were retrospectively reviewed. Phase-contrast and 3D-DRIVE were performed to assess cerebrospinal (CSF) pathways through the aqueduct of Sylvius and subarachnoid spaces. In addition to flow velocity measurement at the aqueduct of Sylvius, functional and anatomical correlation was analysed at the level of aqueduct of Sylvius, infracerebellar CSF space and at the third ventriculostomy using Spearman's rank test. RESULTS: Aqueduct of Sylvius was the most common site of obstruction (19 patients) either secondary to focal, multifocal or tubular stenosis, adhesions, or secondary to extrinsic compression. Functional and anatomical correlation was analysed in 58 regions revealing strong correlation (ro = 0.8, p < .001). Functional anatomical mismatch was found in nine regions. Flow velocity measurements revealed diminished flow in most of the cases with obstruction at the aqueduct and normal velocity in cases with obstruction proximal to aqueductal level, while accelerated flow was seen in cases with infra-aqeuductal obstruction. CONCLUSION: Phase-contrast and 3D-DRIVE sequences are essential sequences in the diagnosis of hydrocephalus enabling perfect localization of the site of obstruction. Both sequences should be interpreted in conjunction to avoid false results. Velocity measurements through the aqueduct can help understand CSF hydrodynamics.

The radiological assessment of colonic replacement of the esophagus in children: A review of 43 cases.

PURPOSE: To define the characteristic radiological features following colonic replacement of the esophagus in children. MATERIALS AND METHODS: The upper gastro-intestinal contrast studies of 43 patients who underwent colonic replacement of the esophagus at our pediatric surgery unit were available for analysis. UGI contrast studies were performed routinely in the post-surgical period in 17 cases (first asymptomatic group), while the rest of contrast studies (26) belonged to a second group of out-patients complaining of dysphagia (18) or dyspepsia (8) following colonic replacement of the esophagus. Based on our observations, we proposed a grading system to describe the degree of colonic redundancy in the thorax. RESULTS: Redundancy of the colonic conduit in the thoracic cavity was a common radiological finding (62.8%). The redundancy was mild (grade 1) in 18 patients, moderate (grade 2) in eight, and severe (grade 3) in only one patient. In 88.9%, the redundancy was in the right hemi-thorax. Patients presenting with postoperative dysphagia had a stricture at the site of the esophago-colic anastomosis in the neck, which should be differentiated from other sites of anatomical narrowing at the inlet and outlet of the thoracic cavity. Gastro-colic reflux was common among patients who underwent colonic replacement of the esophagus without an anti-reflux procedure. CONCLUSION: Colonic replacement of the esophagus in children results in considerable anatomical alterations. Knowledge about the normal post-surgical changes and imaging features of the commonly encountered complications can increase the diagnostic confidence among radiologists and clinicians when dealing with these cases.