Semi-quantitative indices of cardiac uptake in patients with suspected cardiac amyloidosis undergoing 99mTc-HMDP scintigraphy.

BACKGROUND: 99mTc-HMDP scintigraphy has proved its efficacy in non-invasive diagnosis of cardiac amyloidosis (CA) and is currently interpreted according to the Perugini qualitative assessment. Several semi-quantitative indices have been proposed to overcome inherent possible limitations of visual grading. Our aim was to comparatively evaluate six different indices and their diagnostic performance. METHODS: We retrospectively reviewed scintigraphy of 76 patients (53 ATTR, 12 AL, 11 LVH) who underwent diagnostic evaluation at our centre. ROC-curve analysis was performed to identify optimal cut-off and relative diagnostic accuracy of six different indices (of which one was proposed for the first time), both in identifying CA patients and in discriminating patients according to their Perugini score. RESULTS: Heart/Whole-body ratios proved to be the most accurate (100%) in identifying CA patients. Heart/Pelvis ratio (with soft tissue background correction) offered acceptable accuracy (98%), with the largest area under the curve (AUC) (0.98) in discriminating patients with Perugini ≥ 2. Heart/Contralateral Lung ratio confirmed to be exposed to confounding background noise in case of simultaneous lung uptake. Heart/Skull ratio had the worst performance, with six false-negative patients in ATTR identification. CONCLUSION: Heart/Whole-body ratios may be robust and effective semi-quantitative indices for the evaluation of CA by means of scintigraphy.

Prognostic and diagnostic value of [18F]FDG-PET/CT in restaging patients with small cell lung carcinoma: an Italian multicenter study.

BACKGROUND: The presence of residual disease after initial treatment in small cell lung cancer (SCLC) influences prognosis and impacts patient management. To date, few data exist on the value of fluorine-18-fluorodeoxyglucose ([F]FDG)-PET/computed tomography (CT) in SCLC at restaging. Therefore, in restaging patients with SCLC, we aimed to (a) evaluate the prognostic value yielded by [F]FDG-PET/CT and (b) assess the diagnostic agreement between [F]FDG-PET/CT and contrast-enhanced computed tomography (ceCT). PATIENTS AND METHODS: From a multicenter database, we evaluated 164 patients with SCLC who underwent [F]FDG-PET/CT for restaging purposes. PET scans were evaluated visually to identify the presence of recurrence. For each patient, the maximum and the mean standardized uptake value (SUVmax and SUVmean, respectively), metabolic tumor volume, and total lesion glycolysis were calculated, taking into account the lesion with the highest [F]FDG uptake (namely, the index lesion) in the local recurrences, lymph node involvement, and distant metastasis categories. Kaplan-Meier curves were computed to assess the effects of [F]FDG-PET/CT findings on overall survival (OS) and progression-free survival. Furthermore, the agreement between PET/CT and ceCT in detecting metastases was evaluated in 119 patients on a patient-based analysis (Cohen's κ; P < 0.05). RESULTS: The presence of metastatic lesions at [F]FDG-PET/CT was associated with a significantly shorter OS (P = 0.039) and progression-free survival (P < 0.001). Higher SUVmax showed a trend toward a shorter OS (P = 0.065). The K-agreement between ceCT and PET/CT in recurrent SCLC was 0.37 (P < 0.001). PET/CT and ceCT showed the same number of lesions in 52 (43.7%) patients, whereas PET/CT detected additional lesions in 35 (29.4%) patients. CONCLUSION: Detection of metastatic lesions at restaging by [F]FDG-PET/CT can predict a higher rate of progression and negatively influence OS in patients with SCLC. [F]FDG-PET/CT and ceCT seem to be complementary imaging modalities in patients with metastatic SCLC.

Accuracy of 99mTc-Hydroxymethylene diphosphonate scintigraphy for diagnosis of transthyretin cardiac amyloidosis.

BACKGROUND AND AIM: Either 99mTechnetium diphosphonate (Tc-DPD) or pyrophosphate (Tc-PYP) scintigraphy plays a relevant role in diagnosing transthyretin cardiac amyloidosis (CA), and labeled radiotracers have been extensively studied in diagnosing CA. Few studies have analyzed and validated 99mTc-Hydroxymethylene diphosphonate (Tc-HMDP). Our aim was to validate the diagnostic accuracy of Tc-HMDP total-body scintigraphy in a cohort of patients with biopsy-proven transthyretin CA. METHODS AND RESULTS: We retrospectively evaluated all patients undergoing 99mTc-HMDP total-body scintigraphy, in adjunct to a comprehensive diagnostic work-up for suspected CA. Sixty-five patients were finally diagnosed with CA, while it was excluded in 20 subjects with left ventricular hypertrophy of various etiologies. Twenty-six patients had AL-CA, 39 had TTR CA (16 TTRm, 23 TTRwt). At Tc-HMDP scintigraphy, 2 AL patients showed a Perugini score grade 1 heart uptake, while 24 showed no uptake. All TTR patients showed Tc-HMDP uptake, with three patients showing a Perugini score grade 1, 16 grade 2, and 20 grade 3, respectively. No uptake was observed in patients with left ventricular hypertrophy. A positive Tc-HMDP scintigraphy showed a 100% sensitivity and a 96% specificity for TTR CA identification. CONCLUSIONS: Tc-HMDP scintigraphy is as accurate as Tc-DPD or Tc-PYP, and may therefore de facto be considered a valuable tool for the diagnosis of TTR CA.

Lung uptake during 99mTc-hydroxymethylene diphosphonate scintigraphy in patient with TTR cardiac amyloidosis: An underestimated phenomenon.

BACKGROUND: Full body scintigraphy using bone tracers plays an important role in defining the type of amyloidosis and in diagnosing the heart involvement (cardiac amyloidosis, CA). No study has been conducted to explore lung retention (LR) in CA and its correlation to heart retention (HR).We evaluated LR in patients undergoing 99mTc-HMDP scintigraphy during evaluation for suspected CA. METHODS AND RESULTS: We enrolled 93 suspected CA patients. Patients underwent a complete diagnostic work up. After diagnostic process 82 patients resulted affected by certain CA (20 AL and 62 TTR), while 11 subjects showed left ventricular hypertrophy (LVH) not caused by CA. 99mTc-HMDP cardiac uptake was evaluated using the Perugini visual score while the modified Janssen score was used for LR estimation (grade 0 no uptake, grade 1 less than ribs, grade 2 more than ribs). RESULTS: 99mTc-HMDP LR was observed in 1/20 AL patient (5%), while 36/62 (58%) TTR patients showed LR with 29 grade 1 (47%) and 7 grade 2 (11%). No LR was observed in patients with LVH and no CA. LR was not evident in patients without HR, present in 1/3 (33%) of the patients with Perugini 1 HR and 11/24 (46%) and 26/36 (72%) of the patients showing respectively a Perugini 2 and a Perugini 3. CONCLUSION: 99mTc-HMDP scintigraphy shows LR in about 60% of TTR subjects, related to the grade of HR. In AL amyloidosis LR is less frequent than in TTR amyloidosis suggesting an aetiological tropism that seems comparable to the already known TTR related cardiac tropism.

Prediction of functional recovery after primary PCI using the estimate of myocardial salvage in gated SPECT early after acute myocardial infarction.

PURPOSE: Primary percutaneous coronary intervention (PCI) in acute myocardial infarction (AMI) aims to achieve myocardial salvage (MS). Because the reference method for measuring MS requires myocardial perfusion imaging (MPI) after tracer injection before PCI, alternative approaches have been proposed, but none has gained wide acceptance. Gated SPECT MPI can assess infarct size (IS), but can also show myocardial stunning. Thus, we compared functional and perfusion abnormalities early after AMI to estimate MS, and to predict left ventricular ejection fraction (LVEF) recovery at follow-up. METHODS: We studied 120 patients with AMI. Gated SPECT MPI was performed early (before hospital discharge) and at 6 months after AMI to measure IS, MS and functional outcome. MS was defined as the difference between the number of segments with abnormal thickening (i.e. the stunned area or area at risk) and the number of segments with abnormal perfusion (i.e. the final IS), expressed as a percentage of the total number of segments in the AHA model. LVEF was calculated using quantitative gated SPECT. RESULTS: The area at risk was 40 ± 25%, IS was 17.3 ± 16% and MS was 22 ± 19%. Early LVEF was 46.6 ± 11.6% and late LVEF was 51.4 ± 11.6%, with 54 patients showing at least an increase in LVEF of more than 5 units. ROC analysis showed that MS was able to predict LVEF recovery with an area under the curve (AUC) of 0.79 (p < 0.0001), and using a cut off >23% detected LVEF recovery with 74% sensitivity and 71% specificity. Conversely, IS was associated with an AUC 0.53 (not significant). CONCLUSION: MS assessed by a single early gated SPECT MPI study can accurately predict LVEF evolution after primary PCI for AMI.