Unusual presentation of mycosis fungoides as a lump in the scalp

We report a case of mycosis fungoides in a 27-year-old woman who presented with a lump in the forehead. The condition was confirmed with tissue diagnosis. Gallium scintigraphy accurately delineated the complete extent of the disease, and served as a reference for objective assessment of response of the disease to treatment.

Functional mapping of human brain in olfactory processing: a PET study

This study describes the functional anatomy of olfactory and visual naming and matching in humans, using positron emission tomography (PET). One baseline control task without olfactory or visual stimulation, one control task with simple olfactory and visual stimulation without cognition, one set of olfactory and visual naming tasks, and one set of olfactory and visual matching tasks were administered to eight normal volunteers. In the olfactory naming task (ON), odors from familiar items, associated with some verbal label, were to be named. Hence, it required long-term olfactory memory retrieval for stimulus recognition. The olfactory matching task (OM) involved differentiating a recently encoded unfamiliar odor from a sequentially presented group of unfamiliar odors. This required short-term olfactory memory retrieval for stimulus differentiation. The simple olfactory and visual stimulation resulted in activation of the left orbitofrontal region, the right piriform cortex, and the bilateral occipital cortex. During olfactory naming, activation was detected in the left cuneus, the right anterior cingulate gyrus, the left insula, and the cerebellum bilaterally. It appears that the effort to identify the origin of an odor involved semantic analysis and some degree of mental imagery. During olfactory matching, activation was observed in the left cuneus and the cerebellum bilaterally. This identified the brain areas activated during differentiation of one unlabeled odor from the others. In cross-task analysis, the region found to be specific for olfactory naming was the left cuneus. Our results show definite recruitment of the visual cortex in ON and OM tasks, most likely related to imagery component of these tasks. The cerebellar role in cognitive tasks has been recognized, but this is the first PET study that suggests that the human cerebellum may have a role in cognitive olfactory processing as well.

Comparison between segmental wall motion and wall thickening in patients with coronary artery disease using quantitative gated SPECT software

This study was performed to evaluate regional wall motion (WM) and wall thickening (WT) using gated myocardial perfusion single photon emission computed tomography (SPECT) and to determine their similarity and disparity in patients with coronary artery disease (CAD). A total of 44 patients underwent 1 day stress/rest (MIBI) gated SPECT. Commercially available quantitative analysis of gated SPECT (QGS) software was used to generate 3D surface display and cine-mode SPECT display. Left ventricle was divided into nine segments to score WM and WT from 0 (no abnormality) to 4 (severe abnormality) by six independent observers. Finally a mean score was calculated for each segment from the scores of six observers. There was fairly good correlation between WM and WT of individual segments (r = 0.62, p < 0.0001). Concordance rate (IWM - WTI < 1) was 85%. A large difference between WM and WT (WM - WT > or = 2) was observed in 15 segments, including 12 segments with greater WM abnormalities and 3 segments with greater WT abnormalities (lateral and inferior walls). Greater WM abnormalities were most commonly observed in anteroseptal segments especially in post coronary artery bypass grafting (CABG) patients. In conclusion, WM and WT showed similarity on QGS studies. However, these two parameters may be determined separately in gated SPECT studies for comprehensive and robust evaluation of the functional status of myocardium. Analyses based on WM assessment alone may lead to erroneous results especially in septal regions.

Heterogeneity of myocardial wall motion and thickening in the left ventricle evaluated with quantitative gated SPECT

BACKGROUND

Global and regional ventricular function may be evaluated by using gated myocardial perfusion single photon emission computed tomography (SPECT). This study investigated two parameters of regional contraction of the left ventricle, segmental wall motion (WM) and wall thickening (WT), to determine their similarity and disparity in each myocardial segment in patients with normal myocardial perfusion.

METHODS AND RESULTS

Thirty-five patients with normal myocardial perfusion and cardiac function (mean left ventricular ejection fraction, 62.6%+/-8.8%) were included in this study. A 1-day stress/rest protocol was used as a means of acquiring technetium 99m (Tc-99m) sestamibi gated SPECT protocol for each patient. A commercially available software package for quantitative gated SPECT (QGS) was used to generate cine loop three-dimensional surface display and SPECT images. The left ventricle was divided into 9 segments to score WM and WT (on a scale of 0 to 4, with 0 being normal and 4 being severely reduced) by 6 independent observers. The WM score was significantly higher than the WT score in the septum, whereas the WM score was lower than the WT score in the inferior segment. Similar WM and WT scores were observed in the remaining segments.

CONCLUSIONS

Heterogeneous myocardial WM and WT were observed by using QGS software. These findings suggest that different criteria are required in each segment to evaluate segmental WM and WT by means of gated myocardial perfusion SPECT.

[Assessment of noninvasive therapy in lung cancer using lung perfusion images]

The purpose of this prospective study was to follow the changes in functional parameters of radionuclide lung perfusion scans and their role in prognostication of lung cancer cases after noninvasive therapy. We studied 91 patients of lung cancer treated with chemotherapy and/or radiotherapy during 1993 to 1997 in our hospital. Lung perfusion scans were acquired pre and post-therapy. An index of lung perfusion, called Improvement Ratio (IR) was defined as a change in the perfusion of diseased lung as a result of treatment. IR was calculated by the following equation under the assumption that perfusion of contralateral lung remained unaffected. [formula: see text] where Q and Q' are pulmonary arterial blood flow pre and post therapy respectively, p is perfusion ratio of diseased lung before therapy and q is that after therapy. We further studied the relationship between IR and change in tumor size. The influence of tumor location, histopathological diagnosis and prognosis of lung cancer were correlated with this newly defined index. IR in the group of patients with complete response or partial response was significantly higher than in those with poor response (2.72 +/- 0.78 versus 0.99 +/- 0.09, p < 0.05). There was no statistical difference between the group with and without radiotherapy. The score was significantly higher for patients with hilar disease compared to those with peripheral lesions (2.80 +/- 0.83 versus 1.02 +/- 0.03, p < 0.05). Similarly, patients with small cell lung cancer depicted higher values of IR than non-small cell lung cancer (3.36 +/- 1.10 versus 1.06 +/- 0.07, p < 0.05). All those subjects who showed IR > 1 had longer survival time than those with IR < 1 (p < 0.05). It is suggested that improvement in the perfusion of diseased lung predicted better prognosis. We conclude that the evaluation of physiological parameters during therapy using lung perfusion scanning, in addition to lesion size assessment will contribute to the comprehensive follow-up of lung cancer.

Analysis of time-density curves of contrast media for improvement of chest dynamic incremental CT

PURPOSE

The goal of this work was to analyze time-density curves (TDCs) of contrast media (CM) in the mediastinal vasculature to optimize chest dynamic incremental CT.

METHOD

Forty-three patients were injected with nonionic CM into the forearm veins with injection rates (ml/s), durations (s), and total amounts (ml) of 2.0, 20, and 40 (protocol 1); 4.0, 20, and 80 (protocol 2); and 2.0, 40, and 80 (protocol 3). TDCs were obtained for the pulmonary trunk (PA) and ascending (AA) and descending (DA) aorta from dynamic scans. Areas under the curves (AUCs) of TDCs for imaginary 30 s scans were evaluated.

RESULTS

AUC peaks were obtained after 10, 17, and 19 s (PA, AA and DA; protocol 1; 9, 16, and 18 s (protocol 2); and 18, 25, and 28 s (protocol 3) delay time.

CONCLUSION

Better chest dynamic incremental CT would be expected with scan midpoints a little after the end of injection of CM.

[Assessment of left ventricular function by electrocardiogram-gated myocardial single photon emission computed tomography using quantitative gated single photon emission computed tomography software]

Electrocardiogram (ECG)-gated myocardial single photon emission computed tomography (SPECT) can assess left ventricular (LV) perfusion and function easily using quantitative gated SPECT (QGS) software. ECG-gated SPECT was performed in 44 patients with coronary artery disease under post-stress and resting conditions to assess the values of LV functional parameters, by comparison to LV ejection fraction derived from gated blood pool scan and myocardial characteristics. A good correlation was obtained between ejection fraction using QGS and that using cardiac blood pool scan (r = 0.812). Some patients with myocardial ischemia had lower ejection fraction under post-stress compared to resting conditions, indicating post-stress LV dysfunction. LV wall motion and wall thickening were significantly impaired in ischemic and infarcted myocardium, and the degree of abnormality in the infarcted areas was greater than in the ischemic area. LV functional parameters derived using QGS were useful to assess post-stress LV dysfunction and myocardial viability. In conclusion, ECG-gated myocardial SPECT permits simultaneous quantitative assessment of myocardial perfusion and function.

Sclerosing mediastinitis: findings on fluorine-18 fluorodeoxyglucose positron emission tomography

Whole-body serial positron emission tomography scanning was done using fluorine-18 fluorodeoxyglucose (F-18 FDG) in a patient with a mediastinal mass. Uptake correlated well with the clinical symptoms and aggressiveness of the disease. Based on the F-18 FDG findings, a biopsy specimen was taken from the active region of the mass, which confirmed the diagnosis of sclerosing mediastinitis.

Parametric mapping of cerebral blood flow deficits in Alzheimer's disease: a SPECT study using HMPAO and image standardization technique

This study assessed the accuracy and reliability of Automated Image Registration (AIR) for standardization of brain SPECT images of patients with Alzheimer's disease (AD). Standardized cerebral blood flow (CBF) images of patients with AD and control subjects were then used for group comparison and covariance analyses.

METHODS

Thirteen patients with AD at an early stage (age 69.8+/-7.1 y, Clinical Dementia Rating Score 0.5-1.0, Mini-Mental State Examination score 19-23) and 20 age-matched normal subjects (age 69.5+/-8.3 y) participated in this study. 99mTc-hexamethyl propylenamine oxime (HMPAO) brain SPECT and CT scans were acquired for each subject. SPECT images were transformed to a standard size and shape with the help of AIR. Accuracy of AIR for spatial normalization was evaluated by an index calculated on SPECT images. Anatomical variability of standardized target images was evaluated by measurements on corresponding CT scans, spatially normalized using transformations established by the SPECT images. Realigned brain SPECT images of patients and controls were used for group comparison with the help of statistical parameter mapping. Significant differences were displayed on the respective voxel to generate three-dimensional Z maps. CT scans of individual subjects were evaluated by a computer program for brain atrophy. Voxel-based covariance analysis was performed on standardized images with ages and atrophy indices as independent variables.

RESULTS

Inaccuracy assessed by functional data was 2.3%. The maximum anatomical variability was 4.9 mm after standardization. Z maps showed significantly decreased regional CBF (rCBF) in the frontal, parietal and temporal regions in the patient group (P < 0.001). Covariance analysis revealed that the effects of aging on rCBF were more pronounced compared with atrophy, especially in intact cortical areas at an early stage of AD. Decrease in rCBF was partly due to senility and atrophy, however these two factors cannot explain all the deficits.

CONCLUSION

AIR can transform SPECT images of AD patients with acceptable accuracy without any need for corresponding structural images. The frontal regions of the brain, in addition to parietal and temporal lobes, may show reduced CBF in patients with AD even at an early stage of dementia. The reduced rCBF in the cortical regions cannot be explained entirely by advanced atrophy and fast aging process.

Tc-99m HMPAO SPECT in the evaluation of Alzheimer's disease: correlation between neuropsychiatric evaluation and CBF images

The purpose of this study was to evaluate the effects of various covariants on the distribution pattern of Tc-99m HMPAO in patients with Alzheimer's disease by correlation analysis. Twenty patients with Alzheimer's disease and 15 age matched normal subjects participated. Tc-99m HMPAO brain SPECT and x ray computed tomography (CT) were acquired for each subject. SPECT images were transformed to a standard size and shape by automated image registration (AIR) and were used for group comparison by means of SPM96. Voxel based covariance analysis was performed on standardised images taking the age of patients, severity of disease (clinical dementia rating scale, mini mental state examination, physical self maintenance scale), and atrophy indices as variables. There was significantly decreased regional cerebral blood flow (rCBF) in the frontal, parietal, and temporal regions in the patient group (p<0.001), more marked in those patients having severe dementia. Covariance analysis disclosed that aging and severity of disease have a pronounced effect on rCBF, especially that of the left parietal region.

Detection of CBF deficits in neuropsychiatric disorders by an expert system: a 99Tcm-HMPAO brain SPET study using automated image registration

The aims of this study were to develop an objective method for assessing rCBF deficits using a statistical image analysis protocol and to validate its effective use in clinical practice. 99Tcm-HMPAO brain SPET images were acquired for 40 normal subjects, 10 patients with Alzheimer's disease and 10 patients with depression. Automated image registration was used to standardize the size and shape of the brain structures for all subjects. The images of the first 30 normal subjects were used to construct a normal database. The CBF images of the other 10 normal subjects and the 20 patients were compared voxel by voxel with the normal database to map CBF abnormalities by statistical evaluation. The results were compared with the clinical reports of CBF images. The expert system detected all rCBF deficits reported by the nuclear physicians. Some additional areas with special information, like atrophy and bilateral asymmetry, were also identified by the expert system. We conclude that this expert system can delineate CBF deficits with sufficiently high accuracy, differentiating normal from abnormal CBF images using voxel-based comparisons. The use of an expert system improves rCBF SPET image evaluation.

Follow-up of improvement in regional cerebral blood flow and mental status in Alzheimer's disease: a case report

Cerebral SPECT imaging has the potential to make important contributions in the follow-up care of patients with Alzheimer's disease. An unusual case of a patient who showed a follow-up cerebral blood flow pattern different from that routinely seen in Alzheimer's disease patients is reported here. Qualitative and voxel-based objective evaluation of follow-up scans revealed improvement in parietotemporal deficits that had been observed on a baseline study. This change was observed without significant further deterioration in ratings by dementia batteries. This case shows that a baseline regional cerebral blood flow study might be necessary for reference and comparison in the proper follow-up care of Alzheimer's disease patients.

Lesion-to-background ratio in nonattenuation-corrected whole-body FDG PET images

The purpose of this study was to compare the diagnostic efficacy of attenuation-corrected and nonattenuation-corrected whole-body 18F-fluorodeoxyglucose (FDG) PET images to determine an adequate method that can semiquantitatively evaluate nonattenuation-corrected images.

METHODS

Whole-body PET studies were performed in 24 fasting patients with various tumors (lung cancers, n = 18; mediastinal tumors, n = 4; breast cancers, n = 2) 30-40 min after a bolus injection of 18F-FDG. Transmission scans followed emission data acquisition. Reconstructed attenuation-corrected and uncorrected images were displayed simultaneously and the relative FDG uptake in lesions and corresponding background areas was evaluated by the region of interest method. Both types of images were also compared with X-CT scans and conventional nuclear medicine scans for diagnostic efficacy.

RESULTS

Attenuation-corrected and uncorrected images were found to be equally sensitive for detecting lesions. There was a strong linear correlation between lesion-to-background (L/B) ratios calculated on attenuation-corrected and uncorrected images (r = 0.98; p < 0.001). Significant differences in L/B ratios between attenuation-corrected and uncorrected images were present in only 6 of 55 lesions (11%). Standardized uptake ratios (SURs) in attenuation-uncorrected images did not correlate with SURs in attenuation-corrected images nor with L/B ratios in uncorrected images.

CONCLUSION

The efficacy of attenuation-uncorrected FDG PET images in evaluating tumors is similar to that using attenuation-corrected images. Uncorrected images provide not only clinically useful but also quantitative information equivalent to that provided by attenuation-corrected images. However the L/B ratio is the only available index that can be used for quantification of uncorrected images.

Use of automated image registration to generate mean brain SPECT image of Alzheimer's patients

The purpose of this study was to compute and compare the group mean HMPAO brain SPECT images of patients with senile dementia of Alzheimer's type (SDAT) and age matched control subjects after transformation of the individual images to a standard size and shape.

METHODS

Ten patients with Alzheimer's disease (age 71.6 +/- 5.0 yr) and ten age matched normal subjects (age 71.0 +/- 6.1 yr) participated in this study. Tc-99m HMPAO brain SPECT and X-ray CT scans were acquired for each subject. SPECT images were normalized to an average activity of 100 counts/pixel. Individual brain images were transformed to a standard size and shape with the help of Automated Image Registration (AIR). Realigned brain SPECT images of both groups were used to generate mean and standard deviation images by arithmetic operations on voxel based numerical values. Mean images of both groups were compared by applying the unpaired t-test on a voxel by voxel basis to generate three dimensional T-maps. X-ray CT images of individual subjects were evaluated by means of a computer program for brain atrophy.

RESULTS

A significant decrease in relative radioisotope (RI) uptake was present in the bilateral superior and inferior parietal lobules (p < 0.05), bilateral inferior temporal gyri, and the bilateral superior and middle frontal gyri (p < 0.001). The mean brain atrophy indices for patients and normal subjects were 0.853 +/- 0.042 and 0.933 +/- 0.017 respectively, the difference being statistically significant (p < 0.001).

CONCLUSION

The use of a brain image standardization procedure increases the accuracy of voxel based group comparisons. Thus, intersubject averaging enhances the capacity for detection of abnormalities in functional brain images by minimizing the influence of individual variation.

Mean regional cerebral blood flow images of normal subjects using technetium-99m-HMPAO by automated image registration

The purpose of this study was twofold: to calculate relative uptake values for 99mTc-HMPAO in various regions of the normal brain after alignment and registration to a standard shape and size, and to validate the automated image registration (AIR) program for SPECT-to-SPECT transformation.

METHODS

Thirty subjects took part in this study. Technetium-99m-HMPAO brain SPECT and x-ray-CT scans were acquired. SPECT images were normalized to an average activity of 100 counts/pixel. Intersubject accuracy was evaluated on brain images of 17 normal subjects (mean age = 64.9 +/- 8.7 yr). These images were aligned and registered to a standard size and shape with the help of AIR. Realigned images were overlaid on reference images to determine the overlap areas. Intrasubject accuracy was evaluated by realigning 20 degree rotated brain images with an index calculated as: overlap area/(overlap area + nonoverlap area). Anatomical variability between realigned target and reference images was evaluated by measurements on corresponding x-ray-CT scans, realigned using transformations that were established by the SPECT images. Realigned brain SPECT images of 30 normal subjects (mean age = 50.7 +/- 18.7 yr), including those subjects examined in the accuracy validation study, were used to generate mean and s.d. images. Images based on the mean value of each voxel (n = 30) were compared with other mean images prepared by the human brain atlas (HBA) standardization technique on a voxel-by-voxel basis to generate T maps.

RESULTS

Accuracy indices were 0.98 +/- 0.006 and 0.99 +/- 0.002 for the intersubject and intrasubject evaluations, respectively. The maximum anatomical variability was 4.7 mm after realignment. Paired Student's t-test comparisons of mean HBA and AIR images revealed statistically significant differences for the deep white matter, pons and occipito-temporal regions. These differences could be explained by variation in the population being studied and the protocol for data handling by AIR and HBA.

CONCLUSION

AIR aligns and registers brain SPECT images with acceptable accuracy, without the necessity of MRI or x-ray-CT scans.

A simple computer programme for biokinetic study of 99Tcm-radiopharmaceuticals

A simple programme has been written in GW BASIC to calculate the percentage activity of 99Tcm-radiopharmaceuticals in different tissues after biodistribution. The programme is efficient, easy to handle and produces a permanent record in terms of a final report.