The utility of low-iodine diet in preparation for thyroid cancer therapy with radioactive iodine—A cohort study

Objective: A low-iodine diet (LID) of <50μ iodine/day is recommended as preparation for radioactive iodine (RAI) therapy in patients with differentiated thyroid cancer (DTC). The 24-h urinary iodine excretion (UIE) is utilized to evaluate the iodine-depleted status. The aim of this study was to test the association between UIE and progression-free survival (PFS).

Patients and methods: In total, 70 patients with intermediate- or high-risk DTC, post-total thyroidectomy, adhered to 2 weeks of LID and had UIE measured before RAI therapy. A Cox regression model was performed to study the contribution of UIE to PFS.

Results: The study group consisted of 68% (48/70) of women, aged 41.5 [IQR 31.0, 54.0] years, with tumor size 2.8 [IQR 1.8–4.5] cm, and presence of distant metastases in 22.9% (16/70) of patients. Patients were treated with 1–5 RAI dosages with the median cumulative activity of 150 [IQR 102–314] mCi (5.5 [IQR 3.8–11.6] GBq). During the follow-up of 3.7 [IQR 1.5–6.5] years, 21.4% (15/70) of patients had disease progression. The risk of progression was significantly higher in patients with UIE ≥200 µg/day at the time of RAI administration than in those with UIE <200 µg/day (HR 3.35, 95% CI 1.09–10.34, and p = 0.02). However, the multivariate Cox proportional hazards regression analysis adjusted for age, tumor size, and presence of distant metastases suggested that only distant metastases were independently significantly associated with the risk of progression (HR 5.80 (1.17–28.67), p = 0.03).

Conclusions: Although UIE ≥200 µg/day might be associated with worse PFS in RAI-treated DTC patients, the presence of distant metastases is a strong independent predictor of progression. Less stringent LID might be sufficient to achieve a UIE of <200 µg/day.

Assessment of segmental agreement of T2 mapping versus triple inversion recovery in detection of acute myocardial edema

Background

There are some limitations using the different sequences of clinical cardiac magnetic resonance (cardiac MR) in detection of edema in patients presenting with acute myocardial injury. The purpose of this study is to evaluate the myocardial segmental agreement between the different edema sequences: T2 mapping and turbo inversion recovery magnitude (TIRM) in detection of acute myocardial edema.

Results

Thirty-seven patients presented with acute infarction were sent to cardiac MR to assess myocardial edema. All cardiac MR studies were scanned using cine, TIRM, and late gadolinium enhancement (LGE) in short axis views (SAX). Position of the T2 mapping slices were copied from the TIRM. The left ventricle (LV) was divided into apical, mid, and basal segments per visualization of the papillary muscles. Edema mass was assessed separately in each segment as well as the total edema mass in both the TIRM and T2 mapping. Twenty-four patients of whom 12.5% had multi-territorial coronary lesions and edema were assessed. Myocardial edema was not assessed in thirteen patients (35%) due to significant intra myocardial hemorrhage (T2 mapping < 60 ms). No statistical significance was found between the TIRM and the T2 mapping neither in the total amount of edema (p = 0.79), nor in the LV basal, mid, and apical segments’ edema (p = 0.69, 0.5, and 0.8 respectively). The upper and lower limits of agreements were tested between the TIRM and the T2 mapping of total edema mass, basal segments, mid, and apical ventricular segments were = 18 and − 7.7 g, 11.3 and − 5.1 g, 12.3 and − 5.2 g, and 15.5 and − 7.8 g respectively.

Conclusion

This study supports the proof of the principle that there is no statistical significant difference per myocardial segments between the T2 mapping and routine edema’s sequences. Larger studies are recommended to assess the impact in clinical outcome.

Cardiac MRI T1 mapping and extracellular volume application in hypertrophic cardiomyopathy

Background

Hypertrophic cardiomyopathy (HCM) is one of the commonest inheritable cardiac disorders. Being a global disease with diffuse myocardial fibrosis, it has a wide range of adverse outcomes ending with sudden cardiac death. Cardiac magnetic resonance (CMR) with late gadolinium enhancement (LGE) has become a reference standard for visualization of focal myocardial fibrosis. In the setting of less severe or more diffuse fibrosis, LGE is unlikely to reveal the presence of abnormal tissue given the lack of normal myocardium as a reference. Direct measurement of myocardial T1 time (T1 mapping) may improve these methodologic problems of LGE CMR in the setting of diffuse retention of gadolinium-based contrast material. So, we aim at this study to evaluate the clinical application of CMRI native and post-contrast T1 relaxation in assessing diffuse myocardial fibrosis non-invasively in hypertrophic cardiomyopathy.

Results

There was a significant difference between the percent of fibrosis detected by measuring the extracellular volume percent compared to that detected by LGE, with the former detecting fibrosis in 45.1% of the examined cardiac segments while the latter showed fibrosis in 20.9% of the cardiac segments. Also, measuring the native T1 values showed evidence of fibrosis in about 32.2% of the cardiac segments superseding the percent of fibrosis detected using the LGE alone. The ejection fraction percent showed a negative correlation with the left ventricular mass with a correlation coefficient value of − 0.139 where both interstitial and replacement fibrosis play an important role in the pathophysiology of diastolic dysfunction as well as impairing the myocardial contractility. Also, in cases of obstruction, the extracellular volume (ECV) is more likely to increase in the basal anterior and antero-septal segments as well as the basal inferior segment with P values 0.015, 0.013, and 0.045, respectively.

Conclusion

Diffuse fibrosis was found to be difficult to be distinguished using LGE. The unique ability of CMR to use proton relaxation times provides a quantitative measurement to detect increased interstitial volume in diffuse myocardial fibrosis. Moreover, it showed that in cases of obstruction, the segments exposed to the highest pressure are more vulnerable to the fibrotic process denoting a relationship between the pressure gradient and the adverse myocardial remodeling.

Subtle Myocardial Dysfunction and Fibrosis in Children with Rheumatic Heart Disease: Insight from 3D Echocardiography, 3D Speckle Tracking and Cardiac Magnetic Resonance Imaging

Rheumatic heart disease (RHD) is a major cause of morbidity and mortality in developing countries, so early diagnosis and treatment can reduce morbidity and mortality resulting from subsequent valvular damage. The aim of this study was to detect subtle myocardial dysfunction among children with RHD with preserved left ventricular systolic function. This is a cross-sectional case-control study that was conducted on 30 children with RHD (who had valvular affection of any degree and were not in activity) compared to 23 healthy children. After history taking and cardiac examination, 2D echocardiography, tissue Doppler imaging, 3D-echocardiography and 3D speckle tracking echocardiography were done to both groups, whereas cardiac magnetic resonance imaging was done only to the patient group. The 3D-derived left ventricular end-diastolic volume and sphericity index among patients were significantly increased when compared to controls [131.5 (101.5 to 173.7) vs. 69 (58 to 92), P = 0.001, and 0.46 (0.36 to 0.59) vs. 0.33 (0.29 to 0.38), P = 0.001, respectively]. The 3D-derived ejection fraction and longitudinal strain did not differ significantly among both groups. The 3D-derived global circumferential strain was higher in patients when compared to controls [- 14 (- 16 to - 10) vs. - 11(- 13 to - 10), P = 0.04]. None of the examined patients demonstrated late enhancement myocardial fibrosis. In children with RHD and preserved systolic function, subtle systolic dysfunction could not be detected using conventional and novel non-conventional methods. This may indicate that the myocardial affection during the acute stage of rheumatic carditis is minimal with almost complete resolution.

Can myocardial remodeling be a useful surrogate predictor of myocardial iron load? A 3D echocardiographic multicentric study

The relationship between myocardial iron load and eccentric myocardial remodeling remains an under-investigated area; it was thought that remodeling is rather linked to fibrosis. This study aims to determine whether or not measures of remodeling can be used as predictors of myocardial iron. For this purpose, 60 patients with thalassemia were studied with 3D echocardiography and myocardial relaxometry (T2*) by Cardiac MRI. 3D derived sphericity index was significantly higher in patients with myocardial iron load. It was correlated with T2* with a 100% sensitivity and specificity (cut-off value of 0.34) to discriminate between patients with and without myocardial iron overload.

Left ventricular scar impact on left ventricular synchronization parameters and outcomes of cardiac resynchronization therapy

BACKGROUND

Left ventricular scar, including global scar and lateral wall, plays an important role in predicting response to cardiac resynchronization therapy (CRT).

MATERIALS AND METHODS

Thirty patients underwent CRT implantation. Assessment of left ventricular (LV) dyssynchrony was done through Gated SPECT LV phase analysis. Pre-implantation cardiac magnetic resonance (CMR) with late gadolinium enhancement technique to examine LV scar burden. Echocardiographic examination of LV end-systolic volume (LVES) prior to CRT and 6 months later.

RESULTS

Thirty patients received CRT (mean age 58.7±9.0, 24 males). Reverse LV remodeling (decline ≥15% from baseline VES) was documented in 19 patients. Temporal changes in LV dyssynchrony parameters were correlated to LV reverse remodeling. Applying ROC for predicting CRT non-response showed a cutoff 36.5% of global LV scar burden had a sensitivity of 81.8% and specificity of 68.4%. A cutoff for lateral wall scar burden 40.5% of whole lateral wall had a sensitivity of 72.7% and specificity of 68.4%.

CONCLUSION

Reverse LV remodeling is associated with temporal improvements in LV dyssynchrony parameters. LV scar had an unfavorable impact on CRT response. Both global and lateral wall scar burden could predict CRT nonresponse status.