Isabel Roca

A radiopharmaceuticals schedule for imaging in paediatrics. Paediatric Task Group European Association Nuclear Medicine.

There is no standard schedule for the amounts of radiopharmaceutical administered to children at present. Various alternative methods are currently in practice, all with some support from the literature. Optimization of the amount of radiopharmaceutical to be administered is discussed in relation to the radiation burden of such an examination. The Paediatric Task Group of the European Association of Nuclear Medicine has investigated the current situation and now suggests a method for standardization of administered amounts of radiopharmaceutical in paediatrics. The fraction of the adult amount of radiopharmaceutical to be administered should be calculated from the childs body weight according to the accompanying table. In small infants, the minimum amount of a radiopharmaceutical is discussed and suggested amounts to be administered are presented.

Current Role of Bone Scan with Phosphonates in the Follow-Up of Breast Cancer

A number of studies have demonstrated that bone scintigraphy has high sensitivity and efficacy in the early detection of bone metastases from several tumours, including breast cancer. Bone scintigraphy is the most definitive tool for diagnosing and monitoring metastatic spread of breast cancer. However, in the past decade there has been a wide debate on its impact on survival time, morbidity and quality of life. Worldwide economic restrictions and these studies have led to the adoption of an almost minimalist policy for breast cancer follow-up using evidence-based guidelines. The recommended breast cancer surveillance testing includes only a few procedures (history, physical and breast self-examination, patient education on symptoms, pelvic examination). The routine use of additional tests, such as blood cell count, tumour markers, liver ultrasonography, bone scan and chest X-rays, is not recommended. Accordingly, scintigraphy should be reserved for a limited number of patients. On the other hand, early diagnosis of bone involvement may reduce the risk of skeletal related events, thus leading to a significant improvement in quality of life. Furthermore, new drugs (e.g. bisphosphonates) can now delay the onset of bone metastasis and reduce the number of patients who experience skeletal complications. In conclusion, the evidence of the clinical usefulness of bone scintigraphy (to allow early planning of new treatments in advanced disease) has to be re-evaluated, possibly by large randomised prospective trials.

Usefulness of sentinel lymph node detection in early stages of cervical cancer

PurposeSentinel lymph node (SLN) mapping in combination with surgical biopsy is an emerging technique for use in the early stages of cervical cancer. The purpose of this study was to evaluate the technique in a series of 40 consecutive women with early stage cervical cancer.MethodsForty patients with early stage cervical cancer [FIGO stage IA2 (2), IB1 (34), IB2 (1) or IIA (3)] were referred for radical hysterectomy with pelvic lymphadenectomy. Patients were submitted to preoperative lymphoscintigraphy (four 99mTc-nanocolloid injections around the tumour) and intraoperative SLN detection. Hand-held or laparoscopic gamma probes were used to locate SLNs during surgery.ResultsThe mean number of SLNs was 2.5 per patient (interiliac 49%, external iliac 19%). Of the total of 99 SLNs, six, in four women, showed metastases (all 68 non-SLNs removed were negative). In the other 36 patients, all the removed lymph nodes (sentinel and non-sentinel) were negative (0% false negative rate). During the follow-up (median 25 months), only two patients presented distant metastases: one died 6 months after surgery (two of three SLNs positive, both hot and blue), while the second patient is alive 4 years after surgery (lung metastasis, no isotope drainage, negative blue SLN). The survival rate was 95% and disease-free survival, 97%.ConclusionSLN surgical biopsy based on lymphoscintigraphy and blue dye is a feasible and useful technique to avoid lymph node dissection in the early stages of cervical cancer. It has a high negative predictive value, can be incorporated into clinical routine (laparoscopy or open surgery) and is close to achieving validation in this setting.

Change in clinical management of sentinel lymph node location in early stage cervical cancer: The role of SPECT/CT

OBJECTIVE The aim of this study was to investigate the feasibility of the sentinel lymph node (SLN) identification with SPECT/CT lymphoscintigraphy imaging in the early stage invasive cervical cancer in patients undergoing radical hysterectomy and pelvic lymphadenectomy. METHODS Between March 2007 and June 2009, a prospective consecutive study was designed for SLN mapping. Twenty-two patients with cervical cancer FIGO stage IB1 (n=20) or stage IIA1 (n=2) underwent SLN identification with preoperative SPECT/CT and planar images (technetium-99m colloid albumin injection around the tumor) and posterior intraoperative detection with both blue dye and a handheld or laparoscopic gamma probe. Complete pelvic lymphadenectomy was performed in all cases by open (n=2) or laparoscopic (n=20) surgery. RESULTS In the present series, a total of 35 SLN were detected with planar images and 40 SLN were identified and well located by SPECT/CT lymphoscintigraphy (median 2.0 nodes per patient). In 5/22 patients (22.7%) SPECT/CT procedure improves the number of localized SLN. Intraoperatively, 57 SLNs were identified, with a median of 3 SLNs per patient by gamma probe (a total of 53 hot nodes) and a median of 2 nodes per patient after blue dye injection (a total of 42 blue nodes). Microscopic nodal metastases (eight nodes, corresponding to four patients) were confirmed in 18.18% of cases; all these lymph nodes were previously detected as SLN. The remaining 450 nodes, including SLNs, following complete pelvic lymphadenectomy, were histologically negative. CONCLUSIONS Sentinel lymph node detection is improved by SPECT/CT imaging because of the increased number of SLN detected and the better tridimensional anatomic location, allowing easier intra-operative detection with gamma probe and showing, in this series, a 100% negative predictive value.

A two-year follow-up of cognitive deficits and brain perfusion in Mild Cognitive Impairment and mild Alzheimer’s disease

The 15-Objects Test (15-OT) provides useful gradation of visuoperceptual impairment from normal aging through Alzheimers disease (AD) and correlates with temporo-parietal perfusion. The objectives of this study were to analyze progression of 15-OT performance in mild cognitive impairment (MCI) and AD, and its correlates with cognition and single photon emission computerized tomography (SPECT), as well as to examine neuropsychological and SPECT differences between the MCI patients who developed AD and those who did not. From the initial 126 participants (42/group), 38 AD, 39 MCI, and 38 elderly controls (EC) were reassessed (SPECT: 35 AD, 33 MCI, 35 EC) after two years. The progression of cognitive and SPECT scores during this period was compared between groups, and baseline data between converters and non-converters. The 15-OT was the only measure of progression that differed between the three groups; worsening scores on 15-OT were associated with worsening in verbal and visual retention, and decreased perfusion on left postsubicular area. In the MCI patients, cerebral perfusion fell over the two years in medial-posterior cingulate and fronto-temporo-parietal regions; AD showed extensive changes involving almost all cerebral regions. No SPECT changes were detected in controls. At baseline, the MCI patients who developed AD differed from non-converters in verbal recognition memory, but not in SPECT perfusion. In conclusion, SPECT and 15-OT appear to provide a potential measure to differentiate between normal aging, MCI, and AD. Worsening on 15-OT was related to decreased perfusion in postsubicular area; but further longitudinal studies are needed to determine the contribution of 15-OT as a predictor of AD from MCI.

Guidelines for lung scintigraphy in children

The purpose of this set of guidelines is to help the nuclear medicine practitioner perform a good quality lung isotope scan. The indications for the test are summarised. The different radiopharmaceuticals used for the ventilation and the perfusion studies, the technique for their administration, the dosimetry, the acquisition of the images, the processing and the display of the images are discussed in detail. The issue of whether a perfusion-only lung scan is sufficient or whether a full ventilation–perfusion study is necessary is also addressed. The document contains a comprehensive list of references and some web site addresses which may be of further assistance.

Brain perfusion correlates of visuoperceptual deficits in mild cognitive impairment and mild Alzheimer's disease.

Visuoperceptual processing is impaired early in the clinical course of Alzheimers disease (AD). The 15-Objects Test (15-OT) detects such subtle performance deficits in mild cognitive impairment (MCI) and mild AD. Reduced brain perfusion in the temporal, parietal, and prefrontal regions have been found in early AD and MCI patients. The objectives of this study were to confirm the role of the 15-OT in the diagnosis of MCI and AD and to investigate the brain perfusion correlates of visuoperceptual dysfunction (15-OT) in subjects with MCI, AD, and normal aging. Forty-two AD, 42 MCI, and 42 healthy elderly control subjects underwent a brain Single Photon Emission Tomography (SPECT) and separately completed the 15-OT. An analysis of variance compared 15-OT scores between groups. SPM5 was used to analyse the SPECT data. 15-OT performance was impaired in the MCI and AD patients. In terms of the SPECT scans, AD patients showed reduced perfusion in temporal-parietal regions, while the MCI subjects had decreased perfusion in the middle and posterior cingulate. When MCI and AD groups were compared, a significant brain perfusion reduction was found in temporo-parietal regions. In the whole sample, 15-OT performance was significantly correlated with the clinical dementia rating scores, and with the perfusion in the bilateral posterior cingulate and the right temporal pole, with no significant correlation in each separate group. Our findings suggest that the 15-OT performance provides a useful gradation of impairment from normal aging to AD, and it seems to be related to perfusion in the bilateral posterior cingulate and the right temporal pole.

Inter-observer reproducibility in reporting on renal drainage in children with hydronephrosis: a large collaborative study

PurposeThe goal of this study was to evaluate the inter-observer reproducibility in reporting on renal drainage obtained during 99mTc MAG3 renography in children, when already processed data are offered to the observers.MethodsBecause web site facilities were used for communication, 57 observers from five continents participated in the study. Twenty-three renograms, including furosemide stimulation and posterect postmicturition views, covering various patterns of drainage, were submitted to the observers. Images, curves and quantitative parameters were provided. Good or almost good drainage, partial drainage and poor or no drainage were the three possible responses for each kidney.ResultsAn important bias was observed among the observers, some of them more systematically reporting the drainage as being good, while others had a general tendency to consider the drainage as poor. This resulted in rather poor inter-observer reproducibility, as for more than half of the kidneys, less than 80% of the observers agreed on one of the three responses. Analysis of the individual cases identified some obvious causes of discrepancy: the absence of a clear limit between partial and good or almost good drainage, the fact of including or neglecting the effect of micturition and change of patient’s position, the underestimation of drainage in the case of a flat renographic curve, and the difficulties of interpretation in the case of a small, not well functioning kidney.ConclusionThere is an urgent need for better standardisation in estimating the quality of drainage.

PET/CT in paediatrics: it is time to increase its use!

F-FDG PET and PET/CT have proved to beuseful tools in oncological patients [1]. For example, it hasbeen reported that PET can modify the initial staging inabout 40% of patients with lymphoma, leading tomodification of therapy in 18% of them [2]. Similarresults in terms of clinical management, i.e. changes instaging and treatment, have been described in large seriesof patients with other malignancies. PET and PET/CThave also been shown to exert a high impact ononcological management in the paediatric population [3–5]. However, the low incidence of the paediatric malig-nancies has made it difficult to elucidate the precise role ofthese examinations and to attain evidence-based indica-tions for them. Nevertheless, more and more papers havebeen published demonstrating that FDG PET/CT is alsouseful in children. Results obtained in paediatric lympho-ma patients have shown high rates (up to 23%) of therapychanges owing to FDG PET results [6], and several recentpapers have described the usefulness of this technique inmost other paediatric malignancies, such as neuroblastomaand sarcomas.What is the situation regarding correlative image? Inboth children and adults it is clear that imaging diagnosis ismore accurate when anatomical and metabolic images areinterpreted together. Hybrid equipment and fusion imaging(and PET/CT is probably the reference) provide betterinformation than is acquired by separate anatomical andmetabolic examinations or even by comparison of them.This fact is encouraging imaging specialists (in CT, MRI,nuclear medicine, etc.) to collaborate more closely, therebyincreasing communication, improving reports and increas-ing the clinical impact of imaging modalities [1, 2].Several papers, even in paediatric oncology, havereported that fused PET/CT improves diagnostic accuracycompared with PET alone or side by side comparison ofPET and CT images [6, 7]. An excellent example of thisbenefit is given in a recently published paper from theGerman Society of Paediatric Oncology and Hematologyon Hodgkin’s disease. This prospective, multicentre studycompares the accuracy of conventional imaging methodsand FDG PET in the initial staging of paediatric patientsdiagnosed with Hodgkin’s lymphoma. Twenty-one nodaland six extranodal regions were evaluated by conventionalimaging methods and FDG PET independently, and laterthe images were also compared side by side and fused.Results were statistically superior when anatomical regionswere evaluated using both methods in combination. Nodifferences were observed according to the way in whichthe methods were combined, i.e. side by side viewing orimage fusion. However, the confidence of analysts in theresults was clearly superior when the fusion method wasused [8].In this issue, Zvi Bar-Sever et al. describe the results of aprospective study on 46 consecutive paediatric patients whounderwent

Cognitive, Genetic, and Brain Perfusion Factors Associated with Four Year Incidence of Alzheimer's Disease from Mild Cognitive Impairment

BACKGROUND There is a range of factors that predict the development of Alzheimers disease (AD) dementia among patients with amnestic mild cognitive impairment (MCI). OBJECTIVES To identify the neuropsychological, genetic, and functional brain imaging data that best predict conversion to AD dementia in patients with amnestic MCI. METHODS From an initial group of 42 amnestic MCI patients assessed with neurological, neuropsychological, and brain SPECT, 39 (25 converters, 14 non-converters) were followed for 4 years, and 36 had APOE ε4 genotyping. Baseline neuropsychological data and brain SPECT data were used to predict which of the MCI patients would develop dementia by the end of the 4 years of observation. RESULTS The MCI patients who had converted to AD dementia had poorer performance on long-term visual memory and Semantic Fluency tests. The MCI subjects who developed dementia were more likely to carry at least one copy of the APOE ε4 allele (Hazard Risk = 4.22). There was lower brain perfusion in converters than non-converters, mainly in postcentral gyrus. An additional analysis of the SPECT data found differences between the MCI subjects and controls in the posterior cingulate gyrus and the basal forebrain. When the brain imaging and neuropsychological test data were combined in the same Cox regression model, only the neuropsychological test data were significantly associated with time to dementia. CONCLUSION Although the presence of reduced brain perfusion in postcentral gyrus and basal forebrain indicated an at-risk condition, it was the extent of memory impairment that was linked to the speed of decline from MCI to AD.