99mTc isonitrils biophysical aspects in pulmonary tuberculosis. Part I. In vivo evaluation of 99mTc MIBI and 99mTc Tetrofosmin biophysical localization mechanisms.

UNLABELLED: The aim of our study was to compare the role of lung perfusion scintigraphy with 1mTc MIBI and 99mTc Tetrofosmin (Mw) for the initial diagnostic evaluation of pulmonary tuberculosis-PTB). MATERIAL AND METHOD: Two groups of new PTB diagnosed patients, without treatment, were studied: group I--41 patients were imaged with 99mTc MIBI (sex ratio men:women = 17:24, mean age 25 years, 26 positive Mycobacterium Tuberculosis (MT) smears, 15 negative MT smears), group II--40 patients were imaged with 99mTc Mw (sex ratio men:women = 21:19; mean age: 32.5 years; 31 positive MT smears, 9 negative MT smears. Both groups received a 7.4 MBq (0.2 mCi)/kg radiotracer i.v. dose. Two anterior planar 3000000 counts/image on the thorax, one at 15 minutes and the other at 60 minutes after radiotracer administration and a SPECT acquisition were performed. For 99mTc Mw, three extra images were, in addition, performed, at 5, 90 and 120 minutes, in order to compare its kinetic with the known 99mTc MIBI kinetic. Clinical, radiological (Rx) and bacteriologic assessments of the patients were also done. RESULTS: Qualitatively, radiotracer uptake classification was coded: without uptake (-); low uptake (+); moderate uptake (++); high uptake (+++). Three identical interest regions were drawn: on the pathologic site, on a homolateral normal pulmonary field and on a myocardial field. The quantification has been assessed using three indexes (counts/pixel): I1= lesion/ normal; I2 = lesion/heart; I3 = normal/heart. We have found a significant difference between the mean value of I1:1.484, in the case of 99mTc MIBI versus 1.95 in the case of 99mTc Mw. The sensibility of the method was 96% for 99mTc MIBI versus 94% for 99mTc Mw, the specificity being 86 % for 99mTc MIBI versus 88% for 99mTc Mw. CONCLUSION: Both radiotracers are useful for the imaging evaluation of PTB, and can give evidence of new sites, related to radiology. The contrast between pathologic and normal uptake is more evident in 99rTc Mw images than in 99mTc MIBI images, how it was demonstrated by the index quantification. The in vivo uptake kinetic for 99mTc Mw seems to be similar with that of 99mTc MIBI for the first 60 minutes but, at 120 minutes showed delayed washout. This can be useful in the differential diagnosis from other lung disease where the radiotracer kinetic is different.

An image pre-processing automatic system for bone scan metastasis evaluation.

Scintigraphic images provide morphologic and functional information referring to pointed human body tissues and organs. Depending on the ability and experience of the nuclear medicine physician and the degree of scintigram complexity, the diagnosis process becomes very difficult sometimes. Image processing might decrease subjectivity and help physicians in decision making in complex cases as bone metastasis diagnosis based on scintigraphic explorations. The aim of this paper is to describe the compulsory steps of a pre-processing method in order to build a database for an automatic final appreciation of pathologic bone scan areas as a percentage of the total bone scintigraphic surface. This may include the scintigraphic result in some metastasis probability category with more accuracy than a simple, subjective appreciation of the scintigram, especially in doubtful cases. This paper points to the steps of the processing method of the database used in the rule-based nuclear medicine aide-decision expert system (NMADES). The objective evaluation of the pathological sites requires image preprocessing operations in a number of steps: histogram transforms, correlated superposition of direct and reversed incidences to reinforce the uptake sites, smoothing by pseudo-cepstrum methods, symmetry axes extraction by robust linear regression and symmetric areas search with fuzzy methods. Some for and against's are underlined in the last section, devoted to conclusions and future work.

Cancer evolution assessment using artificial neural networks.

Artificial Neural Networks have demonstrated good utility to establish disease prognostic, if there are correctly trained. Our aim was to realize Artificial Neural Networks in different cancer types, to evaluate time survival. For the beginning this was applied for breast cancer. The conclusion is that the homogeneity of data entrance sets, the number, and their coding in relation with their importance for cancer prognostic are decisive for the results of the trained ANN. These results can be useful in the physician clinical decision.

[A retrospective study of bone metastases distribution on 420 whole body scans]. / Studiu retrospectiv al distributiei metastazelor osoase pe 420 de scintigrame "corp intreg".

UNLABELLED: 420 patients with cancer of breast, prostate, lung and colon were investigated through 99mTc Methylene-diphosphonate whole body scintigraphy. The presence of pathologic radiotracer uptake was qualitatively and quantitatively analyzed in order to establish the metastases distribution. Patient selection was realized over 2455 whole body scintigraphies effectuated between 1998 and 2001 in our Nuclear Medicine Service. All selected cases were metastases with known origin primary cancer. RESULTS: Using the Qui-square Test we have compared the frequency of nine well delimited skeleton regions involved like metastatic site in the different cancer types. We have found a significant statistic difference of the range of frequency only between breast and prostate cancers as well as between pulmonary and prostate cancers. The mean number of the metastatic involved skeletal regions was significantly greater in breast and prostate cancers in comparison with lung and colon cancers (p < 0.0001). The higher metastases site frequency was the rachis, than the pelvis, the ribs and the sternum. The skull metastases localization is more frequent in breast cancer in comparison with all other cancers (7.67% versus less than 4% in other cancer types). The pelvis was more involved for the metastatic process in prostate neoplasm. On the other hand, the highest mean anatomic sites number per patient was found in breast cancer (5.7) and prostate cancer (4.8) related to colon (3.3) and lung (3.0) cancers. CONCLUSIONS: Even some particularities were evident, in our study, between the metastases distribution in these four cancer types, the data are not sufficient to sustain the existence of a characteristic pattern related to the primary cancer origin. Metastases localization could be, however, related to the metastazation mechanism.

Cerebral injury predicted by transcranial Doppler ultrasonography but not electroencephalography during carotid endarterectomy.

When shunts are selectively used during carotid endarterectomy, the adequacy of collateral cerebral blood flow (CBF) after the carotid artery is clamped is determined by monitors based on different physiologic measurements. In this series of three patients, we used electroencephalography (EEG) to measure neuronal electrical activity and transcranial Doppler ultrasonography (TCD) to measure CBF velocity. In each of our cases, the EEG was unchanged from preclamp values, while TCD CBF velocity was dramatically reduced. All three patients had transient neuropsychometric or neurologic changes after surgery, which resolved.