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PubMedDate not supplied

Science, art, and artifacts: how important is quantification for the practicing physician interpreting myocardial perfusion studies?

Although considerable efforts have been directed toward improving imaging agents and imaging equipment, relatively little attention has been given to factors that optimize image interpretation. Stress myocardial perfusion images are often interpreted by visual inspection alone. This may introduce considerable inter- and intraobserver variability. Importantly, clinical usefulness of myocardial perfusion imaging may not be consistently reproduced in many laboratories using visual analysis. Relative myocardial distribution of imaging agents on either planar or single-photon emission computed tomographic images can be readily quantified and compared with normal data files by computer processing. Quantification of myocardial perfusion images provides a reproducible measure of the extent of perfusion abnormalities and defect reversibility. The extent of perfusion abnormalities has been shown to have prognostic significance. Computer quantification of myocardial perfusion images improves not only the overall diagnostic yield but also enhances reliability, accuracy, confidence, and reproducibility of interpretation.

Coronary Circulation↗

PubMed1999

Non-invasive characterization of cardiac microvascular disease by nuclear medicine using single-photon emission tomography.

In about 10 to 30% of patients with typical angina undergoing coronary angiography for suspicion of stenotic coronary artery disease angiographically normal coronary arteries are found. Kemp et al. in 1973 coined the term syndrome X to describe this entity. In a substantial portion of these patients pathologic findings in myocardial scintigraphy are present. Sensitivity and specificity of thallium-201 exercise imaging by visual analysis of images in the presence of significant coronary stenosis is 84 and 88%, respectively. Several investigators have reported abnormal results in radionuclide exercise tests in patients with angiographically normal coronary arteries. Some of these results can be explained by myocardial bridging, vasospasm, left or right bundle branch block, hypertrophic cardiomyopathy, or absorption artifacts. In the majority of cases, however, these abnormalities are not sufficient to explain the scintigraphic findings. Formerly often claimed "false positive", recent studies suggest that endothelial dysfunction might be the reason for the observed perfusion defects. When comparing patients with angiographically unobstructed coronary arteries with and without perfusion defects in stress myocardial perfusion imaging, patients with pathological results show a significantly lower increase of coronary flow after intracoronary injection of the endothelial-dependent vasodilator acetylcholine. Endothelial-independent vasodilation, however, is not impaired in these patients. In addition, intracoronary Doppler measurements reveal that perfusion defects in myocardial scintigraphy only occur if coronary blood flow in this perfusion area is significantly reduced. These results suggest that regional endothelial dysfunction may cause hypoperfusion in myocardial perfusion imaging and underline the important role of the microcirculation in the distribution of radiotracers. Another striking scintigraphic pattern in patients with microvascular angina is the high incidence of reverse redistribution. These perfusion defects, apparent in images obtained 4 hours after exercise stress testing, often cannot be assigned to the perfusion territory of one of the major epicardial vessels. This results in a marked inhomogeneous radionuclide distribution pattern in resting images. The inhomogeneity is associated with a significant reduced resting coronary flow velocity in these patients. As histologically confirmed microvessel disease is often accompanied by slow-flow phenomenon reflecting decreased resting flow velocity, the results suggest that the inhomogeneous perfusion pattern is caused by microvascular dysfunction. Furthermore, the heterogeneity of nuclide distribution supports the hypothesis that endothelial function is not homogeneous in the entire myocardial microcirculation, but varies considerably. In conclusion, microvascular dysfunction by itself seems to cause regional myocardial hypoperfusion, as documented by myocardial scintigraphy. When interpreting pathological scintigraphic results in patients without significant epicardial stenosis, true blood flow and myocardial perfusion abnormalities must be assumed.

Animals↗

PubMed1993

Assessment of area at risk and efficacy of treatment in patients with acute coronary syndrome using 99mTc tetrofosmin imaging in humans.

The determination of the myocardium at risk before intervention and the change in that region after intervention constitute a promising measurement tool for the assessment of acute therapy. A new 99mTc labeled myocardial blood flow tracer, 99mTc tetrofosmin, is expected to enable the evaluation of myocardium at risk because of the absence of redistribution. This preliminary study was performed in 9 patients with acute coronary syndrome (4 unstable angina and 5 acute myocardial infarction) to investigate whether recovery of perfusion by tetrofosmin imaging parallels mechanical improvement. Tetrofosmin imaging was performed acutely and 3-30 days later. Visual analysis of defect severity was assessed in both studies. Segments with improvement in perfusion were accompanied by significant wall motion recovery compared with normal and unimproved segments (delta WMI: normal segments 0.40 +/- 0.67, improved segments 1.79 +/- 0.68, unimproved segments -0.15 +/- 0.16, p < 0.01 for improved segments compared with other groups), suggesting the efficacy of this tracer for the assessment of the acute therapy. These data suggest that 99mTc tetrofosmin imaging is a useful method for the assessment of the myocardial area at risk and the efficacy of acute therapy in acute myocardial infarction and unstable angina.

Aged↗

PubMed1998

123I-MIBG myocardial scintigraphy in diabetic patients: relationship with 201Tl uptake and cardiac autonomic function.

PURPOSE: To investigate the influence of diabetic myocardial damage (suspected myocardial damage; SMD) diagnosed by 201Tl-SPECT and diabetic cardiac autonomic neuropathy (AN) on myocardial MIBG uptake in patients with non-insulin-dependent diabetes mellitus (NIDDM). SUBJECTS AND METHODS: Eighty-seven diabetic patients divided into four subgroups: 23 with SMD (+) AN (+); 19 with SMD (+) AN (-); 27 with SMD (-) AN (+); 18 with SMD (-) AN (-), and 10 controls were studied. Both planar and SPECT images were taken at 30 minutes (early) and 3 hours (delayed) after 123I-MIBG injection. The heart to mediastinum uptake ratio (H/M) and washout ratio of 123I-MIBG (WR) were obtained from both planar images. On SPECT images, the total uptake score (TUS) was obtained by the 5 point score method by dividing the myocardium into 20 segments on visual analysis. Similarly, the difference between the 201Tl image and the 123I-MIBG image in TUS was taken as the difference in the total uptake score (delta TUS) representing cardiac sympathetic denervation without SMD. RESULTS: On both early and delayed planar images, the mean H/M value in the subgroups of diabetic patients was significantly lower in the SMD (+) AN (+) group than in the control group, but among those subgroups, there was statistically significant difference between the SMD (+) AN (+) and SMD (-) AN (-) groups only on the delayed images. Regarding the WR value, there was no statistically significant difference among subjects. On SPECT image analysis, the diabetic subgroup with AN or SMD had statistically significant lower values for TUS than those of the control group. Among diabetics, there was a statistically significant differences between SMD [+] AN [+] and SMD [-] AN [-] on both early and delayed images. Similarly, the SMD [+] AN [-] group also had significantly lower values than those of SMD [-] AN [-] on early images. Regarding delta TUS, there was a statistically significant differences between AN [+] subgroups and controls. Similarly, the mean value for delta TUS was much higher in AN [+] subgroups than in AN [-] subgroups with or without SMD in diabetes mellitus. CONCLUSION: 123I-MIBG myocardial uptake is affected by both SMD and cardiac autonomic neuropathy. Based on the finding that delta TUS was much higher in AN [+] subgroups and there was no statistically significant difference between SMD [+] AN [+] and SMD [-] AN [+] subgroups, a decrease in myocardial 123I-MIBG uptake might progress independently of SMD.

3-Iodobenzylguanidine↗

PubMed1997

I-123 iomazenil SPECT in patients with mental disorders.

The purpose of this study is visual evaluation of the distribution of I-123 iomazenil in the brains of patients with various types of mental disorder and to examine whether chronic administration of a clinical dose of benzodiazepine (BZ) affects the binding of I-123 iomazenil to BZ receptors (BZR). The subjects were 10 patients with mental disorders (3 males and 7 females) with a mean age of 26.8 yrs (range 19-39 yrs). Four of 10 patients were administered BZ for over 3 months and the other six were free of BZ for over one month. The SPECT images were obtained at 5-25 min (early) and 170-190 min (delayed), after the bolus i.v. injection of 167 MBq of I-123 iomazenil, with a triple-head gamma camera. The images were visually evaluated and the washout ratios of each region were calculated. In visual analysis, abnormalities were recognized in 5 patients on the delaye SPECT. The abnormalities were recognized more frequently in the superior frontal lobe. The washout ratio was higher in the BZ (+) patient group than in the BZ (-) patient group. I-123 iomazenil is useful, because the SPECT image with I-123 iomazenil reflects the distribution of BZR on the brain and provides the different information from that obtained with perfusion SPECT, X-ray CT or MRI. The rapid washout of I-123 iomazenil from the brains of BZ (+) patients suggests that chronic administration of a clinical dose of BZ affects the binding of I-123 iomazenil to BZR.

Adult↗

PubMed2001

Patterns of failure following CT-based 3-D irradiation for malignant glioma.

BACKGROUND: This retrospective study was undertaken to analyze the patterns of failure in patients with malignant glioma after localized irradiation. PATIENTS AND MATERIALS: Recurrence patterns of 46 patients with malignant glioma (glioblastoma: 24, anaplastic astrocytoma: 15, anaplastic oligodendroglioma: 5, unclassified malignant glioma: 2) were studied using CT/MR scans and radiotherapy plan-plots. All patients were operated before and a total dose of 5,940 cGy was given after CT assisted and individually configurated 3-D planning using 7-15 slices at an in between distance of 5 mm. The target volume included a 2-3 cm margin beyond the tumor indicated by preoperative CT scan. The following parameters were analyzed: tumor size and type, size of perifocal edema and whether the edema was fully included into treatment volume and finally the location of the recurrent tumor. The maximal distance between primary tumor and recurrent tumor was measured and also the distance from the border of the primary tumor to the distant border of edema for a visual analysis. RESULTS: Local limited volume irradiation was sufficient since 73.9% of recurrences occurred within 2 cm distance from primary tumor and 93.5% of recurrences occurred completely within 3 cm distance from primary tumor. Regarding the distance between primary tumor and recurrent tumor and the time interval until appearance of recurrent tumor it was not of importance if perifocal edema was included completely into treatment volume or not. CONCLUSION: Limited volume irradiation of malignant glioma with a target volume 3 cm beyond that indicated by preoperative CT scan seems to be sufficient, since 93.5% of recurrences were completely within 3 cm distance from the margin of the tumor. Improvement of the results with larger treatment volumes are unlikely. Complete irradiation of perifocal edema was not found to be necessary.

Adolescent↗

PubMed2002

[Can supplemental imaging with SPECT technique improve the diagnostic value of preoperative Tc-99m-MIBI scintigraphy in primary hyperparathyroidism?].

BACKGROUND: The focus of this retrospective study was to evaluate if the additional use of SPECT improves the diagnostic value of the preoperative Tc-99m-sestamibi scintigraphy combined with sonography in patients presenting with primary hyperparathyroidism. PATIENTS AND METHODS: 62 patients (43 female, 19 male) were examined by visual analysis of planar Tc-99m-sestamibi scintigraphy, SPECT and ultrasound. 14/62 were suffering from superimposed thyroid disease, 22/62 patients underwent previous neck surgery. 12/62 presented with recurrent hyperthyroidism, in 8/62 cases dystopic parathyroid tissue had been localized. For statistic evaluation these imaging modalities were correlated with the histopathological examinations of the surgical specimens for single use as well as combined use for all patients (group 1) and for the subgroups "histologically confirmed adenoma" (group 2), hyperplastic disease (group 3) "recurrency and/or dystopic parathyroid tissue" (group 4) and "patients presenting with thyroid nodules and/or previous neck surgery" (group 5), respectively. RESULTS: For single use planar scintigraphy showed the highest sensitivity (72%) followed by SPECT (67%) and ultrasound (58%). The combination of planar imaging with ultrasound achieved 83% whereas the combined use of all three modalities increased the sensitivity up to a maximum of 85%. The combined use of the imaging modalities leads to the following results: The histologically proven parathyroid adenomas (group 2) could be detected by planar scintigraphy and sonography with a sensitivity of 87%, for group 3 the combined use of all three modalities reached 69% sensitivity. Group 4 achieved the highest sensitivity (69%) by means of planar scintigraphy and SPECT, whereas group 5 reached 82% by means of planar scintigraphy and ultrasound. CONCLUSION: Planar Tc-99m-sestamibi scintigraphy combined with ultrasound is superior regarding to sensitivity and to the costs for the noninvasive preoperative detection in patients presenting with primary hyperparathyroidism. Due to economic reasons the additional use of SPECT might be limited to patients presenting with recurrent hyperparathyroidism or atypically located parathyroid tissue.

Adult↗

PubMed2001

[Epiluminescent microscopy aspects of initial cutaneous melanoma metastases].

BACKGROUND AND OBJECTIVE: Especially small and initial cutaneous melanoma metastases (CMMs) are tumours with inconspicuous clinical and sometimes histological features which may be difficult to differentiate from other melanocytic lesions. The present study was performed to determine whether epiluminescence microscopic (ELM) criteria could increase the accuracy in preoperative evaluation of CMMs. PATIENTS/METHODS: Thirty photographed and histologically verified CMMs were examined retrospectively using ELM in order to visualize a multitude of morphological features permitting the recognition of malignancy. The colour slides obtained by the photography were subjected to a secondary 30-80 fold magnification in order to conduct a visual analysis. The 50 naevi in the control group were all histologically benign. RESULTS: Five of the 15 features studied were shown to differ significantly between the two groups. Polymorphic angiectatic base pattern and vascular aneurysms, areas of polymorphic and horizontally dilated capillaries, peripheral erythema, saccular pattern and a light brown halo had a specificity of 90-98% and a sensitivity of 40-46% for CMMs (p<0.001). Peripheral grayish patches, lesions surrounded by gray streaks and microscopic ovoid blood lakes were absent in the benign group. CONCLUSIONS: The prevalence of distinct ELM criteria in CMMs enhances the diagnostic accuracy of malignancy in melanocytic skin lesions.

Color↗

PubMed2001

[Multi-rotation CT and acute respiratory distress syndrome. Animal experiment studies].

PURPOSE: Aim of the study was to investigate alveolar inspiration and expiration using multiscan CT. Results of a visual assessment using a scoring system were compared with density ranges known to represent alveolar ventilation best. METHOD: Pigs were examined before and after lavage-induced ARDS. All animals were examined using dynamic multiscan CT. The visual assessment was done by a scoring system proposed by Gattinoni. The results were compared with planimetric determination of defined density ranges. RESULTS: In the healthy lung, the visual analysis showed higher scores at lower airway pressures with a marked gradient, whereas at higher pressures neither opacities nor gradients were observed. In ARDS-lungs, the scores were double as high as in healthy lungs at low pressures. At the same time the differences between inspiration and expiration were minor. There was good correlation between lung density measurements and lung opacities under different airway pressures. In healthy lungs, the greatest area increase is found between -910 and -700 HU. The biggest area growth in the ARDS-model is observed between -910 and -300 HU. CONCLUSION: Dynamic multiscan CT allows for determining different ventilation-relevant lung compartments and lung density ranges.

Animals↗

PubMed2001

Imitation of novel and well-known actions: the role of short-term memory.

Four experiments were carried out using the action span paradigm. In experiment 1 we found that well-learnt, meaningful (MF) actions were imitated better than novel, meaningless (ML) actions. In experiments 2 and 3, during the encoding of MF and ML actions, participants were required to carry out different suppression tasks. In experiment 2 we replicated the advantage of MF actions over ML actions and also found that the motor suppression shortened the action span more than the other forms of suppressions (spatial and articulatory). Action encoding and motor suppression tapping the same subsystem, temporarily holding the motor information, could explain the reduced motor span obtained in experiment 2. Two alternative explanations that could have accounted for this effect were ruled out in experiments 3 and 4. In experiment 3 we verified whether the reduction of the action span was produced by the different combination of the articulatory suppression with motor suppression or with the spatial suppression. In experiment 4, we demonstrated that the reduction was not due to the motor suppression being more difficult than the other types of suppression. The critical finding that the spans of well-learnt, MF actions are longer than those of novel, ML actions observed in experiments 1 and 2 was interpreted in terms of different processing routes engaged in the imitation of these two types of actions. MF actions can be imitated along both a semantic, indirect route and a direct route leading from the visual analysis of the action to the motor system. In contrast, the imitation of ML actions is accomplished along the direct route only.

Brain↗

PubMed2000

Language and motor control.

We investigated the possible influence of automatic word reading on processes of visuo-motor transformation. Subjects reached and grasped an object on which the following Italian words were printed: "VICINO" (near) or "LONTAN" (far) on an object either near or far from the agent (experiments 1, 2); PICCOLO (small) or "GRANDE" (large) on either a small or a large object (experiment 4); and "ALTO" (high) or "BASSO" (low) on either a high or a low object (experiment 5). The kinematics of the initial phase of reaching-grasping was affected by the meaning of the printed words. Namely, subjects automatically associated the meaning of the word with the corresponding property of the object and activated a reach and/or a grasp motor program influenced by the word. No effect on initial reach kinematics was observed for words related to object properties not directly involved in reach control (experiment 3). Moreover, in all the experiments, the presented words poorly influenced perceptual judgement of object properties. In experiments 5-7, the effects of the Italian adjectives "ALTO" (high) and "BASSO" (low) on reaching-grasping control were compared with those of the Italian adverbs "SOPRA" (up) and "SOTTO" (down). Adjectives influenced visual analysis of target-object properties, whereas adverbs more directly influenced the control of the action. We suggest that these effects resemble the structure of a sentence, where adjectives are commonly referred to nouns, and adverbs to verbs. In other words, class of words and, in a broad sense, grammar influenced motor control. The results of the present study show that cognitive functions such as language can affect visuo-motor transformation. They are discussed according to the notion that a strict relation between language and motor control exists, and that the frontal cortex can be involved in interactions between automatic word reading and visuo-motor transformation.

Adolescent↗

PubMed2001

Early development of the gubernaculum and cremaster sac in estrogen receptor knockout mice.

AIM exogenous estrogen causes gubernacular atrophy and cryptorchidism in fetal rodents. Mice with an estrogen receptor-alpha (ERalpha) disrupted gene mutation (alphaERKO) were studied to determine whether ablation of endogenous estrogen action, through ERalpha, had an effect on gubernacular development. Serial sagittal sections were made of the pelvis in fetal and day 7 postnatal wild-type and alphaERKO mice with the estrogen receptor-alpha "knockout" gene mutation. Wild-type (n = 24), heterozygote (n = 13) and alphaERKO mice (n = 12) were sacrificed at 16, 17 and 18 days fetal life and at 7 days postnatally. The size of the gubernaculum, cremaster muscle, cremaster sac, and the width of the sac at both ends in day 7 mice were quantitated by computer analysis. Visually and statistically the ERKO mice could not be separated from the wild-type mice during fetal life. At day 7 postnatally, a thicker cremaster sac was noted morphologically, and also a statistically significant difference was seen in the width of the cremaster sac at the sac's tip. Sac area, cremaster muscle area and the width of the sac at the sac's end did not differ significantly. Overall there is minimal phenotypic change observed in the alphaERKO mouse compared to wild-type at the early developmental stages investigated. However, at postnatal day 7, there is a difference in the width of the cremasteric sac tip. This suggests that the effect of ERalpha, and thus signaling on the developing gubernaculum, occurs late in development. Alternatively, an action from the recently discovered ERbeta may be involved. Exploration of a betaERKO and the double knock-out alphaERKO/betaERKO mouse should be informative in evaluating the effect of endogenous estrogens in gubernacular development.

Animals↗

PubMed2002

Head and neck imaging with PET and PET/CT: artefacts from dental metallic implants.

Germanium-68 based attenuation correction (PET(Ge68)) is performed in positron emission tomography (PET) imaging for quantitative measurements. With the recent introduction of combined in-line PET/CT scanners, CT data can be used for attenuation correction. Since dental implants can cause artefacts in CT images, CT-based attenuation correction (PET(CT)) may induce artefacts in PET images. The purpose of this study was to evaluate the influence of dental metallic artwork on the quality of PET images by comparing non-corrected images and images attenuation corrected by PET(Ge68) and PET(CT). Imaging was performed on a novel in-line PET/CT system using a 40-mAs scan for PET(CT) in 41 consecutive patients with high suspicion of malignant or inflammatory disease. In 17 patients, additional PET(Ge68) images were acquired in the same imaging session. Visual analysis of fluorine-18 fluorodeoxyglucose (FDG) distribution in several regions of the head and neck was scored on a 4-point scale in comparison with normal grey matter of the brain in the corresponding PET images. In addition, artefacts adjacent to dental metallic artwork were evaluated. A significant difference in image quality scoring was found only for the lips and the tip of the nose, which appeared darker on non-corrected than on corrected PET images. In 33 patients, artefacts were seen on CT, and in 28 of these patients, artefacts were also seen on PET imaging. In eight patients without implants, artefacts were seen neither on CT nor on PET images. Direct comparison of PET(Ge68) and PET(CT) images showed a different appearance of artefacts in 3 of 17 patients. Malignant lesions were equally well visible using both transmission correction methods. Dental implants, non-removable bridgework etc. can cause artefacts in attenuation-corrected images using either a conventional 68Ge transmission source or the CT scan obtained with a combined PET/CT camera. We recommend that the non-attenuation-corrected PET images also be evaluated in patients undergoing PET of the head and neck.

Adolescent↗

PubMed2002

Visualisation of bladder cancer using (11)C-choline PET: first clinical experience.

Fluorine-18 fluorodeoxyglucose (FDG), the most widely used radiopharmaceutical in positron emission tomography (PET) for oncological purposes, is unsuitable for imaging of bladder cancer owing to high excretion into the urine. More specific PET radiopharmaceuticals which are not excreted into urine would be welcome. Carbon-11 labelled choline (CHOL) is a new radiopharmaceutical potentially useful for tumour imaging and is not excreted into the urine. We prospectively studied the visualisation of bladder cancer using CHOL PET. Eighteen patients with bladder cancer and five healthy volunteers were included. Bladder cancer was first diagnosed by transurethral resection or by biopsy of the tumour. Next, PET images were performed before surgical treatment by cystectomy. The histopathological findings after cystectomy were used as the gold standard. PET images were performed on either an ECAT 951/31 or an ECAT Exact HR+ system. Attenuation-corrected PET images were obtained after injection of 400 MBq CHOL. PET images were analysed by two independent physicians using visual analysis and calculation of the standardised uptake value (SUV). In the normal bladder wall, the uptake of CHOL was low, and the bladder margin was only outlined by minimal urinary radioactivity, if present. In ten patients the tumour was detected correctly by CHOL PET, with an SUV of 4.7+/-3.6 (mean+/-SD). One false positive CHOL PET scan was seen in a patient with an indwelling catheter for 2 weeks prior to the PET scan. In two patients, lymph node metastases were detected by CHOL PET. A micrometastasis <5 mm was not visualised with CHOL PET. In seven patients, no residual tumour was found after surgery. In six of seven patients CHOL PET imaging was negative. In situ carcinoma, dysplasia and a non-invasive urothelial tumour (pTa) remained undetected in three of these six patients. Minimal to no urinary tract radioactivity was seen in 22/23 subjects. Non-specific uptake of CHOL was observed in the small bowel, rectum and prostate gland. CHOL uptake in bladder cancer was avid, visualising the tumour in the virtual absence of urinary radioactivity. No uptake of CHOL was seen in pre-malignant lesions or in small non-invasive tumours. Our results warrant further research into the value of CHOL PET in the clinical management of patients with bladder cancer.

Adult↗

PubMed2002

Voxel-based comparison of rCBF SPET images in frontotemporal dementia and Alzheimer's disease highlights the involvement of different cortical networks.

Characteristic patterns of regional cerebral blood flow (rCBF) reduction, as detected by technetium-99m hexamethylpropylene amine oxime ((99m)Tc-HMPAO) single-photon emission tomography (SPET), may help clinicians in differentiating patients with frontotemporal dementia (FTD) from those with Alzheimer's disease (AD). However, in some cases these patients may share common rCBF abnormalities and the visual analysis and/or the region of interest (ROI) approach may not sensitively detect more localised focal changes that could be more specific for each pathology. Recently, automated voxel-by-voxel statistical analysis of perfusion brain maps has been applied to SPET images. This method has the advantage of including the rCBF information for the whole brain for statistical analysis without any a priori hypothesis regarding the regions possibly involved. This could result in a better characterisation of rCBF differences in brain regions while also reducing the operator's subjectivity and the time required for data analysis. The purpose of this study was to apply such a technique to highlight the specific brain areas showing a relative functional involvement in FTD and AD. Thus, we compared the relative rCBF patterns obtained in eight FTD patients with those obtained in 21 AD patients using (99m)Tc-HMPAO SPET and statistical parametric mapping (SPM). When FTD patients were compared with AD patients, relatively lower rCBF was observed in right medial frontal cortex (BA 8, 9, 10), right anterior cingulate cortex (BA 32), right temporal cortex (BA 21/22), right orbitofrontal cortex (BA 11) and ventrolateral prefrontal cortex (BA 47); in BA 47 the reduction was evident bilaterally but was more marked on the right side. On the other hand, when AD patients were compared with FTD patients, a significant relative rCBF decrease was found in the bilateral superior parietal cortex (BA 7); this decrease was more extensive on the left side, where it also included the inferior parietal (BA 40), superior occipital (BA 19) and temporo-occipital regions (BA 39, 19). The results of this study confirm the preferential involvement of the frontotemporal regions in FTD patients and of the temporoparietal regions in AD patients. Furthermore, they highlight the networks that are more specifically impaired in these disorders and that could be implicated in the emotional-behavioural and cognitive disturbances that characterise FTD and AD respectively.

Aged↗

PubMed2003

Early therapy monitoring with FDG-PET in aggressive non-Hodgkin's lymphoma and Hodgkin's lymphoma.

This study was designed to determine the value of 2-[fluorine-18]-fluoro-2-deoxy- d-glucose positron emission tomography (FDG-PET) in the early assessment of therapy response in lymphoma patients. We studied 20 patients with pathologically proven lymphoma, including 17 patients with aggressive non-Hodgkin's lymphoma and three patients with Hodgkin's lymphoma. All patients underwent whole-body FDG-PET imaging at baseline and after 1-2 cycles of chemotherapy. PET images were analysed visually and quantitatively by calculating the standardised uptake value (SUV). In each patient, we measured the SUV of the tumour demonstrating the highest FDG uptake at baseline study and the SUV of the same tumour after 1-2 cycles of therapy. The achievement of complete response was assessed on the basis of a combination of clinical findings and the results of conventional imaging modalities. Follow-up of progression-free survival (PFS) was obtained for the validation of PET data. Of the 20 patients, ten achieved complete remission at the completion of chemotherapy and the other ten did not respond to chemotherapy. Of the ten responders, four are still in remission (PFS 24-34 months) while the other six have relapsed (PFS 8-16 months). For the prediction of 24-month clinical outcome, visual analysis of PET after 1-2 cycles showed high sensitivity (87.5%) and accuracy (80%) but low specificity (50%). Comparison with the baseline SUVs revealed that the responders showed a significantly greater percent reduction in SUV after 1-2 cycles of therapy as compared with the non-responders (81.2%+/-9.5% vs 35.0%+/-20.2%, P<0.001). In addition, using 60% reduction as a cut-off value, the responders were clearly separated from the non-responders, with the exception of one non-responder. In conclusion, when performed early during chemotherapy, FDG-PET may be predictive of clinical outcome and allows differentiation of responders from non-responders in cases of aggressive lymphoma.

Adult↗

PubMed2004

Long-term prognostic value of exercise 99mTc-MIBI SPET myocardial perfusion imaging in patients after percutaneous coronary intervention.

The purpose of this study was to evaluate the long-term prognostic value of exercise technetium-99m methoxyisobutylisonitrile ((99m)Tc-MIBI) single-photon emission tomography (SPET) imaging in patients after percutaneous coronary intervention (PCI). Three hundred and eighteen consecutive post-PCI patients who underwent exercise and rest (99m)Tc-MIBI SPET myocardial perfusion imaging (MPI) were followed up for 38+/-27 months. Patients with early revascularisation (<3 months after MPI) were excluded. A semiquantitative visual analysis employing a 20-segment and four-point scoring system was used to define the summed stress score (SSS), summed rest score (SRS) and summed difference score (SDS). Death and non-fatal myocardial infarction (MI) were considered as hard events, and late revascularisation procedures (>/=3 months after MPI) as soft events. Fifty-one patients (16.0%) suffered from cardiac events during follow-up, including 1 (0.3%) death, 13 (4.1%) non-fatal MIs, 9 (2.8%) coronary artery bypass grafting procedures and 28 (8.8%) PCIs. According to the SPET results, patients were classified into three groups: patients with normal MPI (SSS=0, n=153), patients with irreversible defects (SDS<3 and SRS>1, n=100) and patients with reversible defects (SDS>/=3, n=65). The annual hard cardiac event rate in patients with reversible defects was 3.9%, which was significantly higher than that in patients with normal MPI (0.2%, chi(2)=7.71; P<0.01). The annual soft cardiac event rate in patients with reversible defects was 10.7%, which was significantly higher than that in patients with irreversible defects (2.5% chi(2)=17.69; P<0.001), and also significantly higher than that in patients with normal MPI (1.5%, chi(2)=33.89; P<0.001). In patients with normal and reversible defects, there was no significant difference in soft and hard cardiac event rates according to whether patients were symptomatic or asymptomatic ( P>0.05). However, the annual soft event rate in patients with irreversible defects and symptoms was 5.0%, which was higher than that of 0.6% in asymptomatic patients (chi(2)=6.11, P<0.05). Multivariate Cox analysis showed that SSS was the best independent predictor for hard cardiac events (chi(2)=12.70; P<0.001) and SDS was the strongest independent predictor for soft cardiac events (chi(2)=11.72; P<0.001). Post-PCI patients who have normal exercise (99m)Tc-MIBI SPET MPI have a good long-term prognosis, while those with reversible defects are at a higher risk for future cardiac events, without correlation to the chest pain symptoms. However, symptomatic patients with irreversible defects have a higher risk for repeat revascularisation, but not for hard events, compared with asymptomatic patients. Exercise (99m)Tc-MIBI SPET MPI has important clinical value for risk stratification and management decision-making in post-PCI patients.

Angioplasty, Balloon, Coronary↗

PubMed2004

(201)Tl-SPECT in low-grade gliomas: diagnostic accuracy in differential diagnosis between tumour recurrence and radionecrosis.

PURPOSE: The aim of this work was to describe the usefulness of a simple (201)Tl single-photon emission computed tomography (SPECT) technique in the differential diagnosis between tumour recurrence and radionecrosis during the follow-up of patients treated for low-grade gliomas. METHODS: The study population comprised 84 patients treated for low-grade gliomas who showed suspicion of tumour recurrence during their follow-up. All patients were examined by neuro-anatomical imaging procedures (CT, MRI) and (201)Tl-SPECT. (201)Tl-SPECT images were assessed by visual analysis based only on the information on the prescription form and by estimation of the uptake index (ratio of mean counts in the lesion to those in the contralateral mirror area). Examiners were blinded to the results of other tests. RESULTS: Under these conditions, the neuro-anatomical procedures yielded 26.2% inconclusive reports, with a global diagnostic accuracy of 0.61, a sensitivity of 0.63 and a specificity of 0.59. The global diagnostic accuracy for (201)Tl-SPECT was 0.83, with a sensitivity of 0.88 and a specificity of 0.76. Diagnostic pitfalls were observed in regions with physiological (201)Tl uptake, i.e. the posterior cranial fossa, diencephalon, lateral ventricles and cavernous and longitudinal venous sinuses. An uptake index cut-off value of 1.25 showed a sensitivity of 0.90 and specificity of 0.80 for detection of tumour activity. CONCLUSION: (201)Tl-SPECT has adequate diagnostic accuracy to be part of routine algorithms in the follow-up of patients with low-grade glioma suspected of tumour recurrence, as an alternative to neuro-anatomical procedures and not solely as a complementary test.

Adult↗