Weighted registration of 123I-FP-CIT SPECT images improves accuracy of binding potential estimates in pathologically low striatal uptake.

To test whether the use of a striatum weighted image may improve registration accuracy and diagnostic outcome in patients with parkinsonian syndromes (PS), weighted images were generated by increasing signal intensity of striatal voxels and used as intermediate dataset for co-registering the brain image onto template. Experimental validation was performed using an anthropomorphic striatal phantom. (123)I-FP-CIT SPECT binding ratios were manually determined in 67 PS subjects and compared to those obtained using unsupervised standard (UWR) and weighted registered (WR) approach. Normalized cost function was used to evaluate the accuracy of phantom and subjects registered images to the template. Reproducibility between unsupervised and manual ratios was assessed by using intra-class correlation coefficient (ICC) and Bland and Altman analysis. Correlation coefficient was used to assess the dependence of semi-quantitative ratios on clinical findings. Weighted method improves accuracy of brain registration onto template as determined by cost function in phantom (0.86 ± 0.06 vs. 0.98 ± 0.02; Student's t-test, P = 0.04) and in subject scans (0.69 ± 0.06 vs. 0.53 ± 0.06; Student's t-test, P < 0.0001). Agreement between manual and unsupervised derived binding ratios as measured by ICC was significantly higher on WR as compared to UWR images (0.91 vs. 0.76). Motor UPDRS score was significantly correlated with manual and unsupervised derived binding potential. In phantom, as well as in subjects studies, correlations were more significant using the WR method (BPm: R(2) = 0.36, P = 0.0001; BPwr: R(2) = 0.368, P = 0.0001; BPuwr: R(2) = 0.300, P = 0.0008). Weighted registration improves accuracy of binding potential estimates and may be a promising approach to enhance the diagnostic outcome of SPECT imaging, correlation with disease severity, and for monitoring disease progression in Parkinsonian syndromes.

The Value of Oro-Pharyngo-Esophageal Scintigraphy in the Management of Patients with Aspiration into the Tracheo-bronchial Tree and Consequent Dysphagia.

CONTEXT: Tracheo-bronchial aspiration is the most invalidating condition which can happen to patients affected by dysphagia, especially when caused by central neurologic disorders; the associated pneumonia episodes represent the most frequent cause of death in these patients. Oro-pharyngo-esophageal scintigraphy (OPES) allows both functional imaging and semiquantitative evaluation of the subsequent phases of swallowing. CASE REPORT: We evaluated by means of OPES a woman who had previously undergone high-dose external beam radiation therapy for a nasopharyngeal carcinoma, which determined tissue fibrosis and progressive dysphagia. CONCLUSION: In this patient with dysphagia, OPES was a simple, inexpensive, noninvasive, and reliable technique that allowed to show the presence of bolus aspiration and quantified tracheobronchial aspirate.

Hybrid SPECT/CT imaging in neurology.

In recent years, the SPECT/CT hybrid modality has led to a rapid development of imaging techniques in nuclear medicine, opening new perspectives for imaging staff and patients as well. However, while, the clinical role of positron emission tomography-computed tomography (PET-CT) is well consolidated, the diffusion and the consequent value of single-photon emission tomography-computed tomography (SPECT-CT) has yet to be weighed, Hence, there is a need for a careful analysis, comparing the "potential" benefits of the hybrid modality with the "established" ones of the standalone machine. The aim of this article is to analyze the impact of this hybrid tool on the diagnosis of diseases of the central nervous system, comparing strengths and weaknesses of both modalities through the use of SWOT analysis.

Parametric MR dynamic imaging for breast lesions characterization and prediction of lymph nodes involvement.

The main purpose of this study was to evaluate Gd-DTPA kinetics for the differential diagnosis between malignant and benign breast lesions. As a secondary aim, Gd-DTPA kinetics in malignant lesions was tested for predicting axillary lymph nodes involvement. Eighty-eight patients who underwent MRI for suspected breast tumor were selected from our database. All patients underwent the same acquisition protocol consisting of pre-contrast and dynamic contrastenhanced MRI. For all of them clinical and histopathological data were available. MR studies were performed on the same 1.5T scanner with a standard dedicated breast coil. Pre- and post-contrast dynamic images were used to calculate R1, R2 relaxation rates and proton density maps. The maximum influx rate (MIR) as well as the corresponding time (TMIR) were derived using R1 relaxation rate maps and relative changes as a function of time. Histopatological analysis led to the diagnosis of 46 breast carcinomas and 42 benign lesions. All breast carcinomas and 24 out of 42 benign lesions showed contrast-enhancement. The mean MIR was 0.75±0.14 (SD) sec-(2) in malignant tumors and 0.53±0.14 (SD) sec-(2) in contrast-enhancing benign breast lesions (p<0.0001). The TMIR was 1.40±0.43 min and 3.01±1.92 min (mean±SD) in enhancing malignant and benign lesions, respectively (p<0.0001). In malignant tumors, TMIR was not significantly different in node negative and node positive carcinomas whereas MIR was significantly lower in node negative carcinomas (0.67±0.11 versus 0.83±0.12 respectively, p<0.0001). Our findings suggest that quantitative assessment of Gd-DTPA kinetics may be an additional tool characterized for enhancing breast lesions and for predicting axillary lymph nodes involvement in malignant breast carcinoma.

SPECT radiopharmaceuticals for dementia.

Over the last decade the interest towards functional neuroimaging has gradually increased, especially in the field of neurodegenerative diseases. At present, diagnosis of dementia is mostly clinical. Numerous modalities of neuroimaging are today available, each of them allowing a different aspect of neurodegeneration to be investigated. Although during the last period many have predicted a forthcoming disappearance of SPECT imaging in favour of the PET imaging, many new radiotracers SPECT, dual-SPECT tracers techniques and receptor targeting designed radiopharmaceuticals are currently at study. Besides, last decade has also assisted to the development of new SPECT imaging systems, most of them integrated with other imaging modalities (MRI, CT, ultrasound techniques), granting improved imaging capabilities. All these improved conditions, especially appealing for the neuroimaging, together with the new radiopharmaceuticals in development may renovate the interest for SPECT clinical applications.