Predictive and prognostic value of left ventricular mechanical dyssynchrony assessed by myocardial perfusion single photon emission computed tomography in asymptomatic patients under hemodialysis.

BACKGROUND: Patients under hemodialysis (HD) have an increased risk of major adverse cardiac events (MACEs). In these patients, myocardial perfusion scintigraphy (MPS) provides useful prognostic information. Left ventricular mechanical dyssynchrony (LVD) has been proven to predict all-cause death in patients under HD. It remains unclear, whether the same prognostic value pertains also to the prediction of MACEs. PATIENTS AND METHODS: Ninety patients under HD (duration range: 2-216 months) with neither history nor symptoms of coronary artery disease at the time of MPS were retrospectively evaluated. All underwent clinical evaluation and MPS with dipyridamole stress test. MPS was reprocessed to derive left ventricular ejection fraction (EF), perfusion scores [summed stress score (SSS) and summed difference score (SDS)] and LVD (phase histogram bandwidth and phase SD).ResultsMACEs were reported in 10 (11.1%) patients as assessed at more than 2 years of follow-up (median 29 months). At univariate analysis, a correlation was demonstrated between MACEs and LVD (P<0.001), BMI (P=0.04), ECG changes during stress (P=0.03), dyspnea (P=0.02), SSS (P=0.04) and SDS (P=0.02). At stepwise multivariate analysis, only LVD (P<0.001), SSS (P=0.01) and SDS (P=0.001) were independent predictors of MACEs. No thresholds of SSS or SDS showed predictive value (P=0.79 for SSS ≥4, P=0.10 for SSS >8 and P=0.66 for SDS ≥2). At survival analysis, patients with LVD had a significantly shorter MACE-free survival (P<0.001). This predictive value held true even in patients with an unremarkable pattern of perfusion. CONCLUSION: In asymptomatic patients without known coronary artery disease under HD, LVD is highly predictive of the onset of MACEs at more than 2 years of follow-up and provides incremental value over perfusion scores alone. A phase analysis on gated MPS should be routinely performed in these patients to yield useful prognostic information.

(99m)Tc-Methoxy-Isobutyl-Isonitrile Scintigraphy Is a Useful Tool for Assessing the Risk of Malignancy in Thyroid Nodules with Indeterminate Fine-Needle Cytology.

BACKGROUND: Thyroid nodular disease is a very common clinical problem. The diagnostic algorithm includes laboratory tests, thyroid ultrasound (US), thyroid scintigraphy, and, if necessary, US-guided fine-needle aspiration cytology. However, cytology results are reported as indeterminate in a not negligible number of patients. This is a central problem in the workup of patients, since about 55-85% of those undergoing surgery do not have thyroid cancer at final histology diagnosis. The aim of this study was to evaluate prospectively the role of (99m)Tc-methoxy-isobutyl-isonitrile ((99m)Tc-MIBI) thyroid scintigraphy in differentiating malignant from benign thyroid nodules with indeterminate cytology using quantitative analysis. METHOD: One hundred five patients affected by nodular thyroid goiter and with a euthyroid or hypothyroid functional status were prospectively evaluated. All patients had a suspicious nodule ≥15 mm in maximal diameter on US. All nodules were "cold" on (99m)Tc-pertechnetate scintigraphy and had a cytological diagnosis of class III or IV according to the Bethesda system. Planar images of the thyroid were acquired 10 and 60 minutes after (99m)Tc-MIBI administration. All cold nodules were MIBI-positive. Using quantitative analysis, the MIBI washout index (WOind) was calculated as a percentage reduction value of mean MIBI nodular uptake between early (+10 minutes) and late (+60 minutes) scans. RESULTS: Subdividing the patients into positive and negative for malignancy (either including or excluding patients with Hürthle cell adenoma) and performing receiver operating characterist curve analysis, the optimal WOind cutoff in differentiating malignant from benign follicular lesions was set at -19%. The overall sensitivity and specificity of (99m)Tc-MIBI quantitative analysis in identifying patients with malignant lesions was 100% and 90.9%, respectively. However, after excluding patients with Hürthle cell adenomas from the negative patient group, the overall sensitivity and specificity both reached 100%. CONCLUSION: The use of MIBI scintigraphy using quantitative analysis in the workup of cold nodules with indeterminate cytology is suggested in order to stratify patient risk for a malignant lesion better, thus reducing the number of patients referred to surgery. Surgical treatment should be planned in those patients with a WOind up to -19%.

Can peptide receptor radionuclide therapy (PRRT) be useful in radioiodine-refractory differentiated thyroid cancer?

We report on a 70-year-old man affected by radioiodine-refractory differentiated thyroid cancer (DTC) in whom metastases were treated by peptide receptor radionuclide therapy (PRRT). Seven years before, patient had undergone total thyroidectomy. Pathological examination was conclusive for DTC. The patient underwent some radioiodine treatments (RaIT). The last post-therapy whole body scan (pT-WBS) performed five days after RaIT did not show abnormal radioiodine uptake but serum thyroglobulin (Tg) value was high in absence of thyroglobulin-antibodies (Tg-Ab). In-111 DTPA-pentetreotide scintigraphy showed several lung lesions with high somatostatin receptor density. Patient underwent PRRT using Lu-177 DOTATOC. pT-WBS scan confirmed the metastases already demonstrated by In-111 DTPA pentetreotide but radioiodine negative.

Thyroid remnant ablation in differentiated thyroid cancer: searching for the most effective radioiodine activity and stimulation strategy in a real-life scenario.

OBJECTIVE: Differentiated thyroid cancer is rare, but the incidence has been increasing in the last few decades. Early treatment is based on surgery and thyroid remnant ablation (TRA) by means of radioiodine therapy. Despite radioiodine being widely used for decades, the choice of ablative activity is generally empirical and no consensus has been reached to date. The aim of our study was to compare the efficacy and safety of different radioiodine activities. In addition, we compared the ablation rate in patients treated in the hypothyroid state or after recombinant human thyroid-stimulating hormone (rhTSH) administration, retrospectively reviewing the records of 471 patients affected by differentiated thyroid cancer. PATIENTS AND METHODS: Patients were subdivided into three groups on the basis of the different activities of radioiodine administered and taking into account the different approaches used to perform the therapy: thyroid hormonal withdrawal or rhTSH stimulation. RESULTS: The success of TRA was evaluated 12 months later. TRA was obtained in 62/79 (78.5%) in group A (1110 MBq in the hypothyroid state), 183/190 (96.3%) in group B [2220 MBq in the hypothyroid state or after rhTSH administration: 87/90 (97%) and 96/100 (96%) patients, respectively], 199/202 (98.5%) in group C [3700 MBq in hypothyroid state or after rhTSH administration: 98/100 (98%) and 101/102 (99%) patients, respectively]. CONCLUSION: Our data demonstrate that 2220 and 3700 MBq radioiodine are more effective compared with 1110 MBq in TRA, without significant differences between 2220 and 3700 MBq or between hypothyroidism and euthyroidism. We suggest rhTSH-aided TRA with 2220 MBq iodine-131, as this approach permits efficacious treatment, thereby reducing side effects, absorbed dose to body and hospital stay.