Investigating the aspect of asymmetry in brain-first versus body-first Parkinson's disease

Parkinson's disease (PD) is characterized by a progressive loss of dopaminergic neurons in the substantia nigra. Recent literature has proposed two subgroups of PD. The "body-first subtype" is associated with a prodrome of isolated REM-sleep Behavior Disorder (iRBD) and a relatively symmetric brain degeneration. The "brain-first subtype" is suggested to have a more asymmetric degeneration and a prodromal stage without RBD. This study aims to investigate the proposed difference in symmetry of the degeneration pattern in the presumed body and brain-first PD subtypes. We analyzed 123I-FP-CIT (DAT SPECT) and 18F-FDG PET brain imaging in three groups of patients (iRBD, n = 20, de novo PD with prodromal RBD, n = 22, and de novo PD without RBD, n = 16) and evaluated dopaminergic and glucose metabolic symmetry. The RBD status of all patients was confirmed with video-polysomnography. The PD groups did not differ from each other with regard to the relative or absolute asymmetry of DAT uptake in the putamen (p = 1.0 and p = 0.4, respectively). The patient groups also did not differ from each other with regard to the symmetry of expression of the PD-related metabolic pattern (PDRP) in each hemisphere. The PD groups had no difference in symmetry considering mean FDG uptake in left and right regions of interest and generally had the same degree of symmetry as controls, while the iRBD patients had nine regions with abnormal left-right differences (p < 0.001). Our findings do not support the asymmetry aspect of the "body-first" versus "brain-first" hypothesis.

Impact of microscopic extrathyroidal extension on differentiated thyroid cancer post-surgical risk of recurrence: a retrospective analysis

PURPOSE

In the last edition of the American Joint Committee on Cancer (AJCC) staging system, differentiated thyroid cancers (DTC) showing microscopic extrathyroidal extension (mETE) are considered comparable to intrathyroidal cancers for their clinical behavior and prognosis. The aim of the study is to evaluate the impact of this updated assessment of T, when applied to the postoperative recurrence risk stratification, according to the American Thyroid Association Guidelines (ATA-RR).

METHODS

One-hundred DTC patients who underwent total thyroidectomy were retrospectively evaluated. The downstaging of mETE was introduced in the definition of T, and the updated classification defined as modified ATA-RR (ATAm-RR). For each patient, post-surgical basal and stimulated thyroglobulin (Tg) levels, neck ultrasound (US) and post-ablative 131-I whole body scan (WBS) reports were considered. The predictive performance (PP) of disease recurrence was calculated both for each single parameter, as well as for all of them.

RESULTS

According to ATAm-RR classification, 19/100 patients (19%) were downstaged. ATA-RR proved a significant PP for disease recurrence (DR) (sensitivity 75.0%, specificity 63.0%, p = 0.023). However, ATAm-RR performed slightly better due to an increased specificity (sensitivity 75.0%, specificity 83.7%, p < 0.001). For both classifications, the PP was optimal when all the above-mentioned predictive parameters were considered.

CONCLUSION

Our results suggest that the new assessment of T considering mETE resulted in a downgrading of ATA-RR class in a significant number of patients. This provides a better PP for disease recurrence, and the best PP was obtained when considering the whole predictive variables together.

P03.11.A Potential role of pre-radiotherapy MRI for target delineation in high-grade gliomas: a multicenter retro-prospective cohort study

Background

The optimal timing for target identification in high-grade glioma (HGG) remains unclear due to variability in the hyper-signal T2/FLAIR between MRI performed at diagnosis, post-surgery and at radiotherapy (RT) start. The aim of this study was to retrospectively confirm that RT planned on delayed MRI might allow to spare more normal tissue without decreasing local tumour control, in order to prospectively evaluate the best standard and advanced MRI and metabolic imaging sequences for clinical tumor volume (CTV) adaptation.

Material and Methods

We analyzed a retrospective cohort of consecutive patients with HGG treated from 2017 to 2020. All patients had a diagnostic MRI and another performed immediately post-surgery or pre-RT. Target volumes were contoured, based on T2/FLAIR, on diagnostic and post-surgery MRI in group A, while in group B on pre-RT MRI. We analyzed GTV and CTV volume, and the percentage increase between them. Moreover, we compared the two groups in terms of clinical-pathological characteristics and progression-free survival (PFS) and overall survival (OS). A prospective study, started on January 2022, has enrolled patients with HGG evaluated by advanced sequences MRI at diagnosis, post-surgery and pre-RT. In addition, some selected patients have undergone diagnostic DOPA-PET and pre-RT DOPA-PET. 2 MRI-guided contours have been performed for each patient: adapted on T2/FLAIR post-surgery and CTV-adapt on pre-RT, to assess study objectives.

Results

In retrospective cohort we analyzed 54 patients (25 group A, 29 group B). The median age of patients was 61 years (IQR 17,75), 93% had an ECOG PS of 0 or 1, 51 were symptomatic at diagnosis. Patients in group B had more frequently MGMT methylation (59 % vs. 28%, p=0.01) while less frequently frontal lobe involvement (60% vs. 24%, p=0.01). The median percentage increase between GTV and CTV was higher in group A than B: 431% (range 62%-7335%) vs 385% (range 53%-3174%), respectively. No significant difference in the pattern of relapse was observed, since &gt;90% of disease recurrences were in-field in both groups. Median PFS and OS of the overall population were 9.5 months (95% CI 7 - 12) and 18.5 months (95% CI 16 - 24), respectively. Patients in group B had a significant better PFS as compared to those in group A (p=0.03), but similar OS. Nevertheless, imbalance in MTMT methylation status between the two groups was a major driver for PFS. Overall, 37 out of 51 patients had improvement in neurological symptoms (p&lt;0.001), with no difference between the two groups (p=0.54).

Conclusion

Our data suggest that CTV adaptation to pre-RT T2/FLAIR may allow reducing RT volume, without affecting symptoms relieving and disease control. Results from the prospective study will help identifying the best adaptation of CTV guided by T2/FLAIR, advanced MRI sequences and metabolic imaging, in order to optimize efficacy and safety of treatment planning.

The Italian Society of Rheumatology clinical practice guidelines for the management of large vessel vasculitis

Objective: Since of the last publication of last recommendations on primary large-vessel vasculitis (LVV) endorsed by the Italian Society of Rheumatology (SIR) in 2012, new evidence emerged regarding the diagnosis and the treatment with conventional and biologic immunosuppressive drugs. The associated potential change of clinical care supported the need to update the original recommendations. Methods: Using the grading of recommendations assessment, development and evaluation (GRADE)-ADOLOPMENT framework, a systematic literature review was performed to update the evidence supporting the European Alliance of Associations for Rheumatology (EULAR) guidelines on LVV as reference. A multidisciplinary panel of 12 expert clinicians, a trained nurse, and a patients’ representative discussed the recommendation in cooperation with an Evidence Review Team. Sixty-one stakeholders were consulted to externally review and rate the recommendations. Results: Twelve recommendations were formulated. A suspected diagnosis of LVV should be confirmed by imaging or histology. In active GCA or TAK, the prompt commencement of high dose of oral glucocorticoids (40-60 mg prednisone-equivalent per day) is strongly recommended to induce clinical remission. In selected patients with GCA (e.g., refractory or relapsing disease or patients at risk of glucocorticoid related adverse effects) the use of an adjunctive therapy (tocilizumab or methotrexate) is recommended. In all patients diagnosed with TAK, adjunctive therapies, such as conventional synthetic or biological immunosuppressants, should be given in combination with glucocorticoids. Conclusions: The new set of SIR recommendations was formulated in order to provide a guidance on both diagnosis and treatment of patients suspected of or with a definite diagnosis of LVV.

Phase and amplitude EEG correlations change with disease progression in people with idiopathic rapid eye-movement sleep behavior disorder

Study Objectives

Increased phase synchronization in electroencephalography (EEG) bands might reflect the activation of compensatory mechanisms of cognitive decline in people with neurodegenerative diseases. Here, we investigated whether altered large-scale couplings of brain oscillations could be linked to the balancing of cognitive decline in a longitudinal cohort of people with idiopathic rapid eye-movement sleep behavior disorder (iRBD).

Methods

We analyzed 18 patients (17 males, 69.7 ± 7.5 years) with iRBD undergoing high-density EEG (HD-EEG), presynaptic dopaminergic imaging, and clinical and neuropsychological (NPS) assessments at two time points (time interval 24.2 ± 5.9 months). We thus quantified the HD-EEG power distribution, orthogonalized amplitude correlation, and weighted phase-lag index at both time points and correlated them with clinical, NPS, and imaging data.

Results

Four patients phenoconverted at follow-up (three cases of parkinsonism and one of dementia). At the group level, NPS scores decreased over time, without reaching statistical significance. However, alpha phase synchronization increased and delta amplitude correlations decreased significantly at follow-up compared to baseline. Both large-scale network connectivity metrics were significantly correlated with NPS scores but not with sleep quality indices or presynaptic dopaminergic imaging data.

Conclusions

These results suggest that increased alpha phase synchronization and reduced delta amplitude correlation may be considered electrophysiological signs of an active compensatory mechanism of cognitive impairment in people with iRBD. Large-scale functional modifications may be helpful biomarkers in the characterization of prodromal stages of alpha-synucleinopathies.

Italian consensus recommendations for a biomarker-based aetiological diagnosis in mild cognitive impairment patients

BACKGROUND AND PURPOSE

Biomarkers support the aetiological diagnosis of neurocognitive disorders in vivo. Incomplete evidence is available to drive clinical decisions; available diagnostic algorithms are generic and not very helpful in clinical practice. The aim was to develop a biomarker-based diagnostic algorithm for mild cognitive impairment patients, leveraging on knowledge from recognized national experts.

METHODS

With a Delphi procedure, experienced clinicians making variable use of biomarkers in clinical practice and representing five Italian scientific societies (neurology - Società Italiana di Neurologia per le Demenze; neuroradiology - Associazione Italiana di Neuroradiologia; biochemistry - Società Italiana di Biochimica Clinica; psychogeriatrics - Associazione Italiana di Psicogeriatria; nuclear medicine - Associazione Italiana di Medicina Nucleare) defined the theoretical framework, relevant literature, the diagnostic issues to be addressed and the diagnostic algorithm. An N-1 majority defined consensus achievement.

RESULTS

The panellists chose the 2011 National Institute on Aging and Alzheimer's Association diagnostic criteria as the reference theoretical framework and defined the algorithm in seven Delphi rounds. The algorithm includes baseline clinical and cognitive assessment, blood examination, and magnetic resonance imaging with exclusionary and inclusionary roles; dopamine transporter single-photon emission computed tomography (if no/unclear parkinsonism) or metaiodobenzylguanidine cardiac scintigraphy for suspected dementia with Lewy bodies with clear parkinsonism (round VII, votes (yes-no-abstained): 3-1-1); ¹⁸ F-fluorodeoxyglucose positron emission tomography for suspected frontotemporal lobar degeneration and low diagnostic confidence of Alzheimer's disease (round VII, 4-0-1); cerebrospinal fluid for suspected Alzheimer's disease (round IV, 4-1-0); and amyloid positron emission tomography if cerebrospinal fluid was not possible/accepted (round V, 4-1-0) or inconclusive (round VI, 5-0-0).

CONCLUSIONS

These consensus recommendations can guide clinicians in the biomarker-based aetiological diagnosis of mild cognitive impairment, whilst guidelines cannot be defined with evidence-to-decision procedures due to incomplete evidence.

18F-FDG PET/CT is a prognostic biomarker in patients affected by bone metastases from breast cancer in comparison with 18F-NaF PET/CT

Aim: To compare 18F-FDG PET/CT and 18F-NaF PET/CT with respect to disease prognostication and outcome in patients affected by bone metastases from breast cancer (BC). Patients, methods: We retrospectively investigated 32 women with BC and documented bone metastases. Semi-quantitative parameters were applied to 18F-FDG PET/CT and 18F-Na PET/CT in order to evaluate disease extent and tumour metabolism. We used time-to-event analyses (Kaplan Meier and COX proportional hazard methods) to estimate progression-free (PFS) and overall survival (OS) in order to assess the independent prognostic value of 18F-FDG PET/CT and 18F-Na PET/CT. Results: The sensitivity of 18F-NaF PET/CT (100%) was higher (p < 0.05) than that of 18F-FDG PET/CT (72% and 72%). None of the 18F-FDG PET/CT-negative patients showed disease progression at the end of follow-up. After adjustment for age, Ki-67 levels, presence of visceral metastases, hormone therapy, duration of bone disease and response to first-line therapy, only 18F-FDG SUV mean [HR 15.7, 95% confidence interval (CI) 1.15-214.5] and 18F-FDG whole-body bone metabolic burden (WB-B-MB) (HR 16.9; 95%CI 1.87-152.2) were independently and significantly associated with OS. None of the 18F-NaF PET/CT parameters were associated with OS. None of the conventional clinical prognostic parameters remained significantly associated with OS after the inclusion of PET/ CT parameters in the model. Conclusion: 18F-FDG PET/CT is independently associated with OS in BC patients with bone metastases and its prognostic impact seems to be higher than conventional clinical and biological prognostic factors. Although 18F-NaF PET/CT has a higher diagnostic sensitivity than 18F-FDG PET/ CT, it is not independently associated with OS.

Anti-tumoral effects of somatostatin analogs: a lesson from the CLARINET study

Octreotide and lanreotide, the first-generation somatostatin analogs, successfully control hormone hyperproduction, and related syndromes, in patients with acromegaly and neuroendocrine tumors. However, their anti-tumor effect, rather evident in large number of pituitary adenomas in acromegalic patients, has been hypothesized for a long time in patients with neuroendocrine tumors as well, although a significant tumor shrinkage has rarely been observed. However, the recent publication of the CLARINET study has strengthened the evidence, already emerged with the PROMID trial, that the long-term treatment with the first-generation long-acting somatostatin analogs may exert an anti-tumor activity on G1 and G2 enteropancreatic neuroendocrine tumors, as well. After the publication, majority of international guidelines have updated their algorithms in line with these results and this class of drugs obtained the indication as anti-tumor agents in the majority of patients with neuroendocrine tumors.

Relationship between circulating anti-thyroglobulin antibodies (TgAb) and tumor metabolism in patients with differentiated thyroid cancer (DTC): prognostic implications

PURPOSE

TgAb have been proposed as tumor markers in DTC. Recent evidence links TgAb levels with DTC aggressiveness. We aimed to evaluate the relationship between TgAb and tumor glucose metabolism in DTC patients.

METHODS

Seventy-one DTC patients who underwent ¹⁸F-FDG PET/CT were included. According to TgAb value and trends, patients were divided into TgAb positive (TgAb+) or negative (TgAb-) as well as in patients with increasing (Inc-TgAb) or decreasing (Dec-TgAb) trend. On the basis of the results of FDG-PET, post-therapy 131I and Tg levels, patients were divided into two groups according to the evidence (ED) or absence (NED) of disease. ED patients were further divided into three subgroups: 1. radioiodine avid with positive ¹⁸F-FDG PET/CT (PET+/131I+), 2. radioiodine refractory with positive ¹⁸F-FDG PET/CT (PET+/131I-) and 3. radioiodine avid with negative ¹⁸F-FDG PET/CT (PET-/131I+). MeanSUV of FDG-avid lesions was assessed and averaged for each patient (SUVmean-pt). T test was performed to assess the difference between SUVmean in TgAb-, TgAb+ and in Inc-TgAb and Dec-TgAb subgroups. Difference in TgAb between ED and NED patients as well as between ED patients and PET+/131I+, PET+/131I- and PET-/131I+ subgroups was compared.

RESULTS

SUVmean was significantly higher in Inc-TgAb with respect to Dec-TgAb subgroup (5.2 ± 1.5 vs. 2.9 ± 1.1, p < 0.05). TgAb were higher only in the ED PET+/131I+ subgroup with respect to NED patients (p < 0.01).

CONCLUSIONS

The relationship between higher tumor metabolism and trend of TgAb supports a prognostic relevance of TgAb in DTC patients. Significantly higher TgAb in radioiodine avid tumors with positive ¹⁸F-FDG PET/CT further testify the role of TgAb as surrogate tumor marker in DTC.

Functional imaging in pre-motor Parkinson's disease

Several non motor symptoms (NMS) can precede the onset of the classical motor Parkinson's disease (PD) syndrome. The existence of pre-motor and even pre-clinical PD stages has been proposed but the best target population to be screened to disclose PD patients in a pre-clinical, thus asymptomatic, stage is still matter of debate. The REM sleep behavior disorder (RBD) often affects PD patients at different stages of the disease and could precede the onset of motor symptoms by several years. However, RBD could also precede other synucleinopathies (namely, dementia with Lewy bodies and multisystem atrophy), and less frequently could be related to other neurological conditions or remain idiopathic. Moreover, not all PD patients exhibit RBD. Despite these caveats, RBD probably represents the best feature to disclose pre-motor PD patients given its high-risk of developing a full motor syndrome. Other clinical clues in the premotor stages of PD undergoing active investigation include hyposmia, depression, and autonomic dysfunction. Effective biomarkers are needed in order to improve the diagnostic accuracy in the pre-motor stage of PD, to monitor disease progression and to plan both pharmacological and non-pharmacological intervention. Functional imaging, in particular radionuclide methodologies, has been often used to investigate dopaminergic and non-dopaminergic features as well as cortical functioning in patients with RBD in its idiopathic form (iRBD) and/or associated with PD. Recently, new tracers to image α-synuclein pathologies are under development. Functional imaging in pre-motor PD, and in particular in iRBD, could improve our knowledge about the underlying mechanisms and the neurodegenerative progress of PD.

Volume of interest-based [18F]fluorodeoxyglucose PET discriminates MCI converting to Alzheimer's disease from healthy controls. A European Alzheimer's Disease Consortium (EADC) study

An emerging issue in neuroimaging is to assess the diagnostic reliability of PET and its application in clinical practice. We aimed at assessing the accuracy of brain FDG-PET in discriminating patients with MCI due to Alzheimer's disease and healthy controls. Sixty-two patients with amnestic MCI and 109 healthy subjects recruited in five centers of the European AD Consortium were enrolled. Group analysis was performed by SPM8 to confirm metabolic differences. Discriminant analyses were then carried out using the mean FDG uptake values normalized to the cerebellum computed in 45 anatomical volumes of interest (VOIs) in each hemisphere (90 VOIs) as defined in the Automated Anatomical Labeling (AAL) Atlas and on 12 meta-VOIs, bilaterally, obtained merging VOIs with similar anatomo-functional characteristics. Further, asymmetry indexes were calculated for both datasets. Accuracy of discrimination by a Support Vector Machine (SVM) and the AAL VOIs was tested against a validated method (PALZ). At the voxel level SMP8 showed a relative hypometabolism in the bilateral precuneus, and posterior cingulate, temporo-parietal and frontal cortices. Discriminant analysis classified subjects with an accuracy ranging between .91 and .83 as a function of data organization. The best values were obtained from a subset of 6 meta-VOIs plus 6 asymmetry values reaching an area under the ROC curve of .947, significantly larger than the one obtained by the PALZ score. High accuracy in discriminating MCI converters from healthy controls was reached by a non-linear classifier based on SVM applied on predefined anatomo-functional regions and inter-hemispheric asymmetries. Data pre-processing was automated and simplified by an in-house created Matlab-based script encouraging its routine clinical use. Further validation toward nonconverter MCI patients with adequately long follow-up is needed.

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¹⁸F-FDG-PET/CT analysis of metabolic differences between MCI converting to AD and HC

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Large and very well controlled cohorts from EADC-Consortium were investigated.

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Data were analyzed by a friendly-to-use Matlab-based script and Support Vector Machine.

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Excellent discrimination between MCI and HC (sensitivity 92%; specificity 91%)

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Highest accuracy reported so far in MCI and promising implementation in clinical routine

Efficacy of sorafenib and impact on cardiac function in patients with thyroid cancer: a retrospective analysis

PURPOSE

Sorafenib has recently been recognized as an important standard option for the management of patients with differentiated thyroid cancer. Although data concerning cardiac safety are available in pan-tumor studies, no data are available on its use in everyday clinical practice in patients with thyroid cancer.

METHODS

In the off-label program of our institution, we enrolled 14 patients with different histological types of thyroid cancer suitable for treatment with sorafenib. Our aims were to evaluate cardiac safety factors-LVEF (left ventricular ejection fraction), heart rate and blood pressure-the cardiac markers NT-proBNP and troponin I, radiological response evaluated by CT and (18)FDG-PET (according to RECIST 1.1 criteria) and biomarker reduction (Eastern Cooperative Oncology Group Performance Status: ECOG PS) 0-2.

RESULTS

Patients with ECOG PS 2 accounted for 36%. After starting sorafenib, many patients displayed reduced or stabilized metabolic activity in target lesions (clinical benefit = 44%), radiologic reduction or stabilization (74%) and decreased cancer markers (90%). Lung metastases displayed the largest reductions in size. Median overall survival (OS) was 7 months and median progression-free survival (PFS) was 3 months. No sign of cardiotoxicity was observed in almost all patients. LVEF was altered in two patients and proved symptomatic in one.

CONCLUSIONS

Sorafenib seems to be effective in reducing disease progression in the early stages of treatment (3-6 months). Responses varied considerably according to the criteria investigated. Cardiac toxicities did not raise concerns and were in line with data reported in other malignancies. However, cardiac monitoring is recommended.

Systemic vascular inflammation in abdominal aortic aneurysm patients: a contrast-enhanced PET/CT study

AIM

The aim of this paper was to investigate the presence of systemic vascular inflammation and its relationship with risk factors and biomarkers of systemic inflammation related to atherosclerosis in asymptomatic abdominal aortic aneurysm (AAA) patients.

METHODS

Thirty AAA patients and 30 age-matched controls underwent contrast-enhanced 2-deoxy-2-[18F]fluoro-D-glucose (FDG) PET/CT. C-reactive protein, erythrocyte sedimentation rate, white blood cell count and differential, serum fibrinogen, D-dimer and full lipid panel were also evaluated. Region of interest analyses were performed to obtain target-to-background (TBR) metabolism of aorta, subclavian, carotid, iliac arteries and AAA. CT-based arterial calcium load (CL) was evaluated. Arterial Metabolism and CL intergroup differences were tested (unpaired t-test). Linear regression analysis was performed only between blood biomarkers on one side and both TBR and ACL of the arterial districts that resulted significantly different between patients and controls on the other. In all the analyses P values <0.05 were considered significant.

RESULT

FDG-uptake was higher with respect to controls in aorta, carotid and iliac arteries (P<0.01, P<0.007, P<0.04 respectively). AAA and aorta metabolism showed an inverse correlation with HDL-chol (P<0.02 and P<0.01, respectively) while only aorta showed a direct correlation with lymphocytes' count (P<0.02). Carotid metabolism was directly correlated with monocytes' count and C-reactive protein concentration (P<0.02 and P<0.004, respectively).

CONCLUSION

The present findings support the relevance of systemic vascular inflammation in all phases of atherosclerosis-related disorders. Moreover they confirm the concept that acute ischemic syndromes might represent the local result of a systemic inflammation rather than the focal involvement of a single arterial lesion.

Trafficking and homing of systemically administered stem cells: the need for appropriate analysis tools of radionuclide images

AIM

Despite its enormous relevance, homing of hematopoietic stem cells (SCs) remains relatively uncertain due to the limitations of measuring small number of systemically administered cells in the different organs. Despite its high sensitivity, radionuclide detection has been relatively underutilized to this purpose since it cannot differentiate hematopietic SCs recruited by target tissues from those circulating in the blood pool. Our study aims to verify the potential of tracer kinetic approaches in estimating the recruitment of labeled SCs after their systemic administration.

METHODS

Twenty-four Lewis rats underwent administration of 2 millions cells labeled with 37 MBq of 99mTc-exametazime. Animals were divided into 2 groups according to administered cells: hematopoietic SCs or cells obtained from a line of rat hepatoma. Cell injection was performed during a planar dynamic acquisition. Regions of interest were positioned to plot time activity curves on heart, lungs, liver and spleen. Blood cell clearance was evaluated according to common stochastic analysis approach. Either fraction of dose in each organ at the end of the experiment or computing the slope of regression line provided by Patlak or Logan graphical approach estimated cell recruitment. At the end of the study, animals were sacrificed and the number of cells retained in the same organs was estimated by in vitro counting.

RESULTS

Cell number, documented by the dose fraction retained in each organ at imaging was consistently higher with respect to the "gold standard" in vitro counting in all experiments. An inverse correlation was observed between degree of overestimation and blood clearance of labeled cells (r=-0.56, P<0.05). Logan plot analysis consistently provided identifiable lines, whose slope values closely agreed with the "in vitro" estimation of hepatic and splenic cell recruitment.

CONCLUSION

The simple evaluation of organ radioactivity concentration does not provide reliable estimates of local recruitment of systemically administered cells. Yet, the combined analysis of temporal trends of tracer (cell) tissue accumulation and blood clearance can provide quantitative estimations of cell homing in the different organs.

Cognitive impairment in degenerative parkinsonisms: role of radionuclide brain imaging

Cognitive impairment in Parkinson's disease (PD) and atypical parkinsonian syndromes is gaining increased clinical significance. The neurochemical and neuropathological basis in the various parkinsonian forms and even in an individual patient are not fully elucidated yet and could be heterogeneous. Loss of dopaminergic, cholinergic and noradrenergic innervation has been suggested to be the underlying neurochemical deficits for cognitive impairment and dementia in PD, but the onset of cognitive impairment and the progression to dementia may not share the same underlying neurochemical basis. Similarly, pathological evidence is also heterogeneous, ranging from subcortical pathology, limbic or cortical Lewy body type degeneration, and Alzheimer's type pathology that can be found even in the same patient with PD dementia (PDD). Typically, the prototype of early cognitive deficit in PD is a dysexecutive syndrome, but other cognitive domains are more involved when dementia develops, mainly including visuospatial, language and memory dysfunction. Functional radionuclide neuroimaging, by means of single-photon emission computed tomography and positron emission tomography, are contributing to characterize the topographic cortical pattern of cognitive impairment, as well as to define the underlying neurochemical deficit. Lastly, the advent of amyloid PET may help clarifying the meaning of amyloid load in diffuse Lewy body disease and PDD. Knowing the neurochemical and pathophysiological substrate of cognitive deficit in patients with PD or other degenerative Parkinsonisms may help the clinician in understanding the clinical condition of an individual patient in order to plan pharmacological and non-pharmacological intervention. The introduction of acetylcholinesterase inhibitors for therapy of PDD is an example of information integration between clinical-neuropsychological and pathophysiological-neurochemical aspects obtained also with the key contribution of functional neuroimaging.

Could [18]F-fluorodeoxyglucose PET/CT change the therapeutic management of stage IV thyroid cancer with positive (131)I whole body scan?

AIM

Stage-IV differentiated thyroid cancer (DTC) patients may present elevated serum thyroglobulin (Tg) levels associated with positive [(131)I] whole-body-scan (WBS). Nevertheless some patients in whom WBS does not reveal new sites of disease show increased Tg levels. This finding prompts thorough restaging in order to exclude the presence of metastases unable to concentrate iodine. The aim of our study was to evaluate the impact of [(18)F]FDG-PET/CT in both the assessment of overall extent of the disease and the therapeutic management in a group of stage-IV DTC patients.

METHODS

On suspicious of non-iodine concentrating additional metastases, 20 stage-IV DTC patients with increasing Tg levels and stable positive post-therapy WBS were enrolled. Conventional imaging (CI) procedures, including neck ultrasonography, bone-scintigraphy and computed tomography (CT) were performed before [(18)F]FDG-PET/CT.

RESULTS

[(18)F]FDG-PET/CT was positive in 16 out of 20 patients (80%). In 9 patients (45%) [(18)F]FDG PET/CT detected a larger number of tumour recurrences/metastatic sites than WBS+CI. [(18)F]FDG PET/CT findings prompted modification of the management of 11 patients (55%), in whom surgery or external radiotherapy were eventually considered more appropriate than radioactive iodine therapy. These further therapies improved the quality of life in several patients but did not change their survival rate.

CONCLUSION

Our results showed that [18F]FDG-PET/CT can detect new radioiodine-negative metastases in advanced DTC patients with unchanged positive WBS and increasing Tg levels. [(18)F]FDG-PET/CT may constitute a useful tool in the choice of the best therapeutic strategy in such difficult cases.

The reversed clock drawing test phenomenon in Alzheimer's disease: A perfusion SPECT study

AIM

To unveil a brain single photon emission computed tomography (SPECT) pattern in Alzheimer's disease (AD) patients, showing a reversed clock drawing test (CDT) phenomenon.

PATIENTS AND METHODS

Among 1,005 consecutive subjects, 9 AD patients who drew a reversed CDT (AD-R) underwent SPECT, which was analysed (SPM2) versus a group of 10 AD patients performing the CDT correctly (AD+) and versus 15 controls (CTR). Brain SPECT in 11 AD patients who mistook the CDT in a common way (AD-) was compared with AD+ and CTR groups.

RESULTS

Relative hypoperfusion was found in AD-R versus CTR in right medial frontal, parahippocampal and subcallosal gyri, and in left insula and superior temporal gyrus. Hypoperfusion was found in AD-R versus AD+ in the right uncus, superior temporal and parahippocampal gyri. In the AD- versus CTR comparison, hypoperfusion was found in left hippocampus, parahippocampal gyrus and superior parietal lobule. In AD-R versus AD+ and CTR merged together, the analysis showed hypoperfusion in the right parahippocampus, medial frontal gyrus, superior temporal gyrus and uncus, in the left insula and superior temporal gyrus.

CONCLUSION

Fronto-temporal dysfunction, especially in the right hemisphere, plays a role in the reversed CDT phenomenon in AD patients, whereas matched AD patients mistaking the CDT in a common way show left posterior temporo-parietal hypoperfusion.

Low thyroglobulin concentrations after thyroidectomy increase the prognostic value of undetectable thyroglobulin levels on levo-thyroxine suppressive treatment in low-risk differentiated thyroid cancer

DESIGN

Recombinant human TSH-stimulated thyroglobulin (Tg) levels (rhTSH-Tg) are sufficient for early follow-up of low-risk differentiated thyroid cancer (DTC) patients after thyroidectomy and radioiodine (131I) remnant ablation (RAI). Serum Tg levels at the time of remnant ablation (ablation-Tg) is thought to be related with rhTSH-Tg and may be predictive of recurrent disease. During long-term follow-up, Tg levels on levo-T4 (L-T4) suppressive treatment (suppressive-Tg) is sufficiently sensitive to avoid further evaluations in patients with undetectable rhTSH-Tg. The aim of our study was to verify whether, in a subgroup of low-risk DTC patients, the association of low ablation-Tg levels (<10 microg/l) with undetectable suppressive-Tg concentrations has a sufficient negative predictive value (NPV) for recurrence of disease, leading to avoid rhTSH testing.

METHODS

We enrolled 169 low-risk DTC patients treated by thyroidectomy + RAI and undetectable suppressive-Tg at 12-month followup. In all patients, we retrospectively evaluated ablation-Tg and rhTSH-Tg. For all patients, 2-yr follow-up was available.

RESULTS

Based on rhTSH-Tg>2 microg/l, relapsing disease was histologically proven in 2 patients. rhTSH-Tg levels between 0.6-2.0 microg/l, with no evidence of disease, was observed in 10 patients (6%). One hundred and fifty-seven patients showed undetectable rhTSH-Tg. The NPV of undetectable suppressive- Tg was 92.8%. The ablation-Tg level was <10 microg/l in 140 patients. In this group, the NPV of undetectable suppressive- Tg was 100%.

CONCLUSION

Our data indicate that undetectable suppressive-Tg value, combined with ablation- Tg levels <10 microg/l, may avoid a significant number of high-cost rhTSH-Tg test.

The need of appropriate brain SPECT templates for SPM comparisons

AIM

Statistical parametric mapping (SPM) is used worldwide to compare brain perfusion single photon emission computed tomography (SPECT) data. The default template within the SPM package used for SPECT image normalization includes images of a group of healthy subjects studied with [(99m)Tc]HMPAO. Since [(99m)Tc]HMPAO and [(99m)Tc]ECD have shown to distribute differently in SPECT studies, we formulated the hypothesis that comparing set of [(99m)Tc]ECD data normalized by means of a [(99m)Tc]HMPAO template may lead to incorrect results.

METHODS

A customized [(99m)Tc]ECD template was built with SPECT and magnetic resonance imaging (MRI) images of 22 neurologically healthy women. Then, two sets of subjects, i.e. a group of patients with very early Alzheimer's disease (eAD) and a matched control group, studied by means of [(99m)Tc]ECD SPECT, were chosen for comparisons. The same statistical approach (t-test between eAD patients and controls and correlation analysis between brain SPECT and a cognitive score) was applied twice, i.e. after normalization with either the default [(99m)Tc]HMPAO template or the customized [(99m)Tc]ECD template.

RESULTS

In the comparison between eAD and controls, a cluster of difference in the posterior cingulate gyrus of both hemispheres was only highlighted when using the customized [(99m)Tc]ECD template, but was missed when using the default [(99m)Tc]HMPAO template. In the correlation between brain perfusion and a cognitive score, the significant cluster was more significant and far more extended, also including the right superior temporal gyrus, using the customized [(99m)Tc]ECD template than using the default [(99m)Tc]HMPAO template.

CONCLUSION

These data suggest the need of customized, radiopharmaceutical-matched SPECT templates to be used within the SPM package. The present customized [(99m)Tc]ECD template is now freely available on the web.

Staging and therapy monitoring of multiple myeloma by 99mTc-sestamibi scintigraphy: a five year single center experience

The aim of the present study was the evaluation of the diagnostic value of 99mTc-sestamibi (MIBI) in the detection of bone marrow involvement in patients suffering from multiple myeloma (MM) and its possible role in the follow-up. Between 1998 and 2003, 68 patients with MM and 42 pts with monoclonal gammopathy of undetermined significance (MGUS) were consecutively enrolled in this study. 51/68 MM patients had active disease (AD), 11/62 were in complete remission (CR) and 6/68 in partial remission (PR) after chemotherapy. 18 patients with MM repeated a 99mTc-MIBI scintigraphic study at least 2 months after high-dose chemotherapy. All the scans were scored semi quantitatively according to extension and intensity of tracer uptake. All MGUS pts had a negative 99mTc-MIBI. As far as the MM pts are concerned, 54/68 (49%) pts (48 with AD, 5 with PR and 1 with CR) had a positive 99mTc-MIBI scan, while the 99mTc-MIBI scan was negative in 14/68 pts (10 with CR, 1 with PR and 3 with AD). The overall sensitivity of the 99mTc-MIBI scintigraphy was 92%; specificity was 96%. In the follow up of the pts treated with chemotherapy 99mTc-MIBI closely paralleled the activity of myeloma bone disease. In conclusion, these results indicate that 99mTc-MIBI scintigraphy closely reflects myeloma disease activity in the bone marrow, and that a negative 99mTc-MIBI scan in patients with suspected MM clearly, though not absolutely, indicates absence of disease or clinical remission. The results of this study suggest a clear diagnostic value of 99mTc-MIBI scintigraphy in patients with MM and its potential role during the follow-up for the monitoring of MM bone disease.

Global cognitive impairment should be taken into account in SPECT-neuropsychology correlations: the example of verbal memory in very mild Alzheimer's disease

PURPOSE

To examine the impact of severity of global cognitive impairment on SPECT-neuropsychology correlations, we correlated a verbal memory test with brain perfusion in patients with very mild Alzheimer's disease (AD), taking into account the Mini-Mental State Examination (MMSE) score as an index of global cognitive impairment.

METHODS

Twenty-nine outpatients (mean age 78.2+/-5.5 years) affected by very mild, probable AD underwent brain SPECT with 99mTc-ethylcysteinate dimer and a word list learning test. SPM99 was used for voxel-based correlation analysis after normalisation to mean cerebellar counts (height threshold: p<0.01). In a first analysis, only age and years of education were inserted as nuisance covariates, while in a second analysis the MMSE score was inserted as well.

RESULTS

In the first analysis, two clusters of significant correlation were found in both hemispheres, mainly including regions of the right hemisphere, such as the inferior parietal lobule, the middle temporal gyrus and the posterior cingulate. Significant correlation in the left hemisphere was observed in the lingual lobule, the parietal precuneus and the posterior cingulate. After taking into consideration the MMSE, the largest cluster of correlation was found in the left hemisphere, including the parietal gyrus angularis, the posterior cingulate and the middle temporal gyrus.

CONCLUSION

The wide differences observed between the correlations achieved with and without taking into account the MMSE score indicate that severity of global cognitive impairment should be considered when searching for brain perfusion-neuropsychology correlations. In the present case, this strategy resulted in correlations that more closely matched neuropsychological models of verbal memory deficit.