Search PubMed⌕ Search

Biomedical subjects

R Montz

Publications and source records attributed to R Montz.

At least 19 recordsLinked to original sources
PubMed2002

Early diagnosis of recurrent breast cancer with FDG-PET in patients with progressive elevation of serum tumor markers.

BACKGROUND: The aim of this work is to assess the diagnostic value of positron emission tomography (PET) with 18F-fluorodeoxyglucose (FDG), in the early detection of tumour recurrence in already treated breast cancer patients in apparent complete remission and with a progressive elevation of tumour markers CEA and/or CA 15.3 without any other clinical or instrumental signs of relapses. METHODS: The author studied 45 women (mean age 58+/-12, range 35-80 years) with histological diagnosis of breast cancer who underwent a tumour marker-guided whole body FDG-PET. All patients were in remission, without any other clinical or instrumental signs of relapses, except for the progressive elevation of CA 15.3 and/or CEA, tested during the follow-up. FDG-PET results were controlled by pathology when histological sampling was possible, by other conventional imaging modalities (US, X-rays, CT, MRI) and/or by clinical follow-up up to 12 months at least. RESULTS: FDG-PET findings were evaluated in 38 patients: 27 resulted positive. Among these 27 PET positive patients 24 were true positive and 3 false positive. Tumour marker guided FDG-PET was also able to discover 3 unknown neoplasms not visualized by other modalities. PET revealed 54 sites of intense focal FDG uptake. The anatomical distribution of these sites was 19 skeleton, 18 lymph node basins, 5 liver, 5 pelvic region, 1 lung, 1 pericardium, 1 pleura, 1 contralateral breast, 2 peritoneum and 1 thyroid bed. Forty-eight of these 54 sites of FDG accumulation were confirmed to be metastases. FDG-PET resulted negative in 11 patients and only in 2 of them the other diagnostic modalities were able to discover metastatic lesions; we had 9 true negative and 2 false positive RESULTS. On the basis of our investigation the performances of tumour marker guided FDG-PET per patient are as follows: sensitivity 92% (24/26), specificity 75% (9/12), positive predictive value 89% (24/27), negative predictive value 82% (9/11), accuracy 87% (33/38). CONCLUSIONS: This study demonstrated the clinical utility of tumour marker-guided PET in the follow-up of breast cancer patients. This diagnostic approach allowed to modify the clinical management in those patients in whom a tumor relapse or unexpected primary neoplasm was discovered.

Adult↗
PubMed1999

[PET-FDG in thyroid cancer with high thyroglobulin levels and negative 131-I scan. A case report].

The value of whole body PET-FDG in the evaluation of metastases has been demonstrated in a wide variety of tumors. In this report, we present the case of a patient with antecedent of papillary thyroid carcinoma, who was operated twelve years ago, and submitted to an ablative dose of residual thyroid tissue through 131I, being the levels of thyroglobulin normals. After twelve years of evolution, the patient refers bag pain and respiratory trouble, appearing in the CT image suspicious of metastases in right pulmonary base. The levels of thyroglobulin were shown increased, being the 131I scan negative. A whole body PET-FDG study was performed in order to exclude metastases of his malignant process, showed multiple high FDG uptake focus in brain, cerebellum, neck, chest, lymphatic nodes and bone, suggestive of dedifferentiated disease These findings were confirmed subsequently in the clinic evolution. Therefore, whole-body PET-FDG is a complementary diagnostic technique for study patients with CDT (Thyroid Differentiated Carcinoma) with 131I scan negative and rising thyroglobulin levels.

Aged↗
PubMed1998

[The role of PET-FDG in questionable diagnosis of relapse in the presence of radionecrosis of brain tumors].

INTRODUCTION: Although CT and MR are sensitive techniques for the detection of cerebral tumours, both have limitations in distinguishing between tumour relapse (TR) and post-treatment radionecrosis (RN). PATIENTS AND METHODS: In this study we have determined the usefulness of metabolic imaging with PET-FDG in such situations. We assessed 70 patients with CNS tumours (22 low grade astrocytomas, 25 high grade astrocytomas, 3 oligodendrogliomas, 13 metastatic tumours and 7 other tumours. All had been treated with radiotherapy and other treatments such as radiosurgery, chemotherapy or different types of surgery, and presented clinical pictures which made it necessary to decide the differential diagnosis of relapse or radionecrosis. RESULTS: In the PET-FDG study visual and semiquantitative analysis was done by SUV (Standardized Update Value). Confirmation of the findings was obtained in 44 cases (24 TR and 20 RN). MR was doubtful or inconclusive in most cases, whilst with PET correct diagnosis was made in all cases. CONCLUSIONS: Metabolic imaging with PET-FGD is better than anatomostructural imaging techniques for differential diagnosis between tumour relapse and radionecrosis in CNS tumours which have been treated. Prospective studies are necessary for evaluation of SUV as a factor for prognosis of survival.

Adult↗
PubMed1996

Technetium-99m tetrofosmin rest/stress myocardial SPET with a same-day 2-hour protocol: comparison with coronary angiography. A Spanish-Portuguese multicentre clinical trial.

Technetium-99m tetrofosmin (Myoview) has unique properties for myocardial perfusion imaging very early after injection of the tracer. We used a very short same-day rest/stress protocol, to be performed within 2 h and evaluated its diagnostic accuracy. The study included 144 patients from seven Spanish and four Portuguese centres with a diagnosis of uncomplicated coronary artery disease (CAD); 78 patients (54%) had no history of prior myocardial infarction. Patients were injected with </=300 MBq 99mTc-tetrofosmin at rest and </=900 MBq approximately 1 h later at peak exercise. Single-photon emission tomographic (SPET) acquisitions were initiated within 5-30 min post injection. The results were compared with those of coronary angiography (CA). The data of 142 patients were completely evaluable (two with non-evaluable images were excluded). The quality of rest images was excellent or good in 86%, regionally problematic in 7%, poor but well interpretable in 5% and non-evaluable in 2%. The overall sensitivity for the detection of CAD was 93%, the specificity 38% and the accuracy 85%. The localization of defects by SPET in relation to the perfusion territories of stenosed vessels (>/=50%) was achieved with a sensitivity of 64% for the left anterior descending artery, 49% for the left circumflex artery and 86% for the right coronary artery, and an accuracy of 71%, 72% and 73% respectively. Concordance of SPET and CA was 62% for single-vessel disease and 68% for multivessel disease. In conclusion, this Spanish-Portuguese multicentre clinical trial confirmed, in a considerable number of patients who underwent coronary angiography, the feasibility of 99mTc tetrofosmin (Myoview) rest/stress myocardial SPET using a very short protocol (2 h).

Coronary Angiography↗
PubMed1995

[The usefulness of 99mTc-tetrofosmin in the diagnosis of pulmonary tumors. A preliminary assessment].

We conducted a preliminary study of captation of the new radiopharmaceutical 99mTc-tetrofosmin in cases of primary carcinoma of the lung, analyzing the results of 5 cases studied before surgery with single photon emission tomography (SPECT) of the lung. The results obtained by imaging were compared with those from surgery. Tumor size ranged between 3.5 and 9 cm. In all cases the images showed that captation of the radiotracer by the neoplasm was satisfactory, leaving the area of the tumor clearly distinguishable from normal adjacent lung tissue and giving no signs of interference caused by absorption of 99mTc-tetrofosmin by contiguous structures (heart or liver). Based on these preliminary results we assert that SPECT of the lung using 99mTc-tetrofosmin may be useful in the clinical diagnosis of malignant lung tumors, although further research must determine to what extent the technique can be relied upon.

Adenocarcinoma↗
PubMed1995

Cerebral perfusion, electrical activity and effects of serotonergic treatment in obsessive-compulsive disorder. A preliminary study.

An abnormally increased glucose metabolism has been described with positron emission tomography (PET) in frontal and caudate regions of obsessive-compulsive patients. Perfusion and electroencephalographic studies have been less conclusive. However, these techniques are, currently, more available than PET and, therefore, deserve further study because of their possible clinical applications. In this article, 13 obsessive-compulsive patients were studied with quantitative EEG and auditory and visual evoked potentials. Six of them were studied also with perfusion single photon emission tomography. A group of 4 patients was studied with both techniques before and after a serotonergic treatment. Increased global, beta, and theta electrical power together with an increased perfusion in frontal regions was observed. The patients also showed a delta power increase over right temporal and frontal regions, together with increased perfusion in the right basal ganglia region as well as a decreased amplitude of the P50 and N100 waves of the auditory evoked potentials over temporal electrodes; these alterations were reduced with treatment. These results are discussed in the context of current data about serotonergic neurotransmission.

Adult↗
PubMed1995

Drug therapy and cerebral perfusion in obsessive-compulsive disorder.

Cerebral perfusion in a previously untreated patient with obsessive-compulsive disorder was studied qualitatively and semi-quantitatively with SPECT before, and during and 6 wk after treatment with clomipramine. The patient's symptoms disappeared while on medication and relapsed after drug withdrawal. At baseline, there was an increased perfusion ratio in the bilateral orbitofrontal, anterior cingular, frontotemporal and right caudate regions. These alterations disappeared during drug therapy. After treatment discontinuation and symptomatic relapse, the same pattern of hyperactivity was found. Semiquantitative measurements after treatment withdrawal showed a return to perfusion values similar to those observed before treatment in subcortical structures. In cortical areas, this level was not completely achieved. Subtraction SPECT images showed perfusion changes at the orbitofrontal, caudate and thalamic levels.

Adult↗
PubMed1994

Vitiligo and other diseases: coexistence or true association? Hamburg study on 321 patients.

In the past, several authors described an association of vitiligo with autoimmune disorders and the presence of different tissue autoantibodies. A review of the literature showed large differences in the results. Therefore, 321 patients with vitiligo (male/female ratio 114/207) were examined to see whether the frequencies of associated diseases and phenomena (i.e. Koebner phenomenon, canities praecox, halo nevi, poliosis circumscripta), the number of pigmented lesions and the presence of autoantibodies are of significance in order to support (a) a subentity of childhood vitiligo and (b) whether there is a true predisposition or association of autoimmune or other diseases in this group of patients. The data confirm earlier results of a prevalence of thyroid disease and the presence of thyroid antibodies, whereas other diseases are a random event. 6.2% of the patients had congenital nevi compared with 2.8% in a normal healthy population. Based on the results of this study and the significant higher risk for development of melanomas in this patient group, an annual checkup is recommended.

Adolescent↗
PubMed1992

Detection of colorectal carcinomas by intraoperative RIS in addition to preoperative RIS: surgical and immunohistochemical findings.

The immunoscintigraphic detection of tumour foci less than 1 cm in diameter fails even with single photon emission tomography (SPET) owing to low contrast against background activity. In an attempt to improve detection of macroscopically invisible tumour spread, intraoperative scintimetry (IOSM) with a hand-held gamma-probe was performed in addition to SPET 24-30 and 41-48 h after injection of the technetium-99m carcinoembryonic antigen (CEA MoA) on 12 patients with colorectal carcinoma and 3 patients with different neoplastic and inflammatory diseases. Tumour specimens were measured in vitro in a gamma well counter. For comparison, the presence and amount of CEA in the tumour cells were evaluated immunohistochemically. After modification, the gamma-probe originally designed for iodine-131 was 20 times more sensitive; activities of 99mTc located close to the collimator hole were measured with absolute sensitivity of 100 cps = 2.5 kBq 99mTc. The unfavourably high background activity affected both the in vitro and in vivo analysis: SPET results had been considered positive in 8 of 15 cases. In vitro tumour/non-tumour (t/nt) ratios greater than 2.0 were found in 4 cases. In vivo IOSM resulted in t/nt ratios greater than 2.0 in only 3 patients. In most cases, there was no coincidence of elevated t/nt ratios from the different methods. A correlation was derived between positive immunoscintimetric in vitro findings and immunohistochemically proven interstitial localization of CEA in tumor cells. In conclusion, the measurement technique of IOSM seems adequate, but clinical success will depend on a more specific enrichment of MoA in tumour tissue.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Radioimmunodiagnosis of pancreatic cancer disease.

From a theoretical point of view, immunoscintigraphy of exocrine pancreatic cancer offers itself as a promising diagnostic method. However, the actually available clinical and experimental data point out that the indication for diagnostic application in patients with pancreatic carcinoma has to be viewed more critically than in the case of, e.g., colorectal cancer disease. The quality of imaging depends on a lot of factors, such as the cellular antigen expression, the affinity of the MAbs to the corresponding antigens expressed by the cells, tumor vascularization, tumor size, and unspecific background activity as well as on labeling techniques, the kind of antibodies used, and the technical equipment. All these factors may vary from one patient to the other and from one center to the other. In summarizing the available clinical data, we have to state that immunoscintigraphy does not allow early detection of pancreatic cancer and, consequently, does not allow screening for early stages in asymptomatic patients. Even nowadays primary diagnosis and staging should be based on the imaging methods of ultrasound, CT and/or ERCP, and angiography. With respect to detection of local recurrence and especially peritoneal carcinosis, immunoscintigraphy, however, may be superior when compared to the other imaging methods. The potential clinical value for followup and as a preinvestigation to assess the probability of effective MAb treatment has still to be evaluated in prospective clinical studies. Altogether, a lot of experimental and clinical work remains to be done to introduce immunoscintigraphy of pancreatic cancer into clinical practice as a routine method.

Animals↗
PubMed1990

Detection of human collateral circulation by vasodilation-thallium-201 tomography.

Coronary arteriolar vasodilation may provoke redistribution of flow to collateral-dependent jeopardized myocardium. To assess the physiologic significance of collaterals, 80 consecutive post-infarction patients (age 58 +/- 8 years) underwent vasodilation-redistribution thallium-201 tomographic imaging after administration of 0.56 mg of intravenous dipyridamole/kg body weight. Circumferential profile analysis of thallium-201 uptake and redistribution in representative left ventricular tomograms provided quantitative assessment of transient and fixed defects and separation between periinfarctional and distant inducible hypoperfusion. Tomographic perfusion data were correlated to wall motion and collateral circulation between distinct anatomic perfusion territories. Patients were grouped according to presence (59%) or absence (41%) of angiographically visible collateral channels to jeopardized myocardium. In the presence of collaterals, distant reversible defects were larger than in absence of collaterals (p less than 0.05); the extent of combined periinfarctional and distant redistribution was also larger in collateralized patients (p less than 0.025), whereas the size of the persistent perfusion defect was similar in both groups. By prospective analysis the tomographic perfusion pattern of combined periinfarctional and distant redistribution revealed a sensitivity of 85% and a specificity of 78% for the detection of significant collateral circulation in this group of patients. Thus, using the exhausted flow reserve as a diagnostic tool, vasodilation-thallium-201 tomography has the potential to identify and quantitate collateralized myocardium in post-infarction patients and may guide diagnostic and therapeutic decision-making.

Cardiac Catheterization↗
PubMed1990

Assessment of post-infarction jeopardized myocardium by vasodilation--thallium-201 tomography: impact on risk stratification.

For the purpose of risk stratification 80 consecutive patients (mean age 58 +/- 7 years) with a chest pain syndrome after documented myocardial infarction underwent tomographic vasodilation-redistribution thallium-201 perfusion imaging, using 0.56 mg kg-1 intravenous dipyridamole. Tomograms were analysed for size and location of reversible and fixed perfusion defects and correlated to angiographic characteristics, left ventricular ejection fraction and wall motion, collateral status and 1-year prognosis, as measured by cardiac events within 12 months. No serious side-effects were noted with the diagnostic use of intravenous dipyridamole. According to the perfusion pattern three subgroups of post-infarction patients were identified: (1) by ischaemia at a distance with redistribution in non-infarct related territories (n = 48); (2) by peri-infarctional ischaemia with redistribution in the territory of the 'infarct artery' (n = 9); and (3) by exclusively fixed defects without redistribution (n = 23). Ischaemia at a distance was associated with a larger reversible defect than peri-infarctional ischaemia (P less than 0.05) and the pattern without redistribution (P less than 0.005); the fixed defect size, however, was similar in all three subgroups. In addition, the severity of coronary artery disease (Gensini score and number of diseased vessels) and the degree of collateralization was higher in the presence of a redistribution pattern (P less than 0.05), although no significant differences in global and regional function were noted as a function of thallium-201 redistribution.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Recovery of left ventricular function after myocardial infarction can be predicted immediately after thrombolysis by semiquantitative intracoronary thallium and technetium pyrophosphate scintigraphy.

The accuracy with which intracoronary thallium and technetium pyrophosphate scintigraphy during intracoronary thrombolysis predicts myocardial salvage was studied in 58 patients with acute myocardial infarction by comparing the acute scintigraphic findings with subsequent left ventricular function. Scintigrams obtained before and immediately after thrombolysis were interpreted by three independent observers using a scoring system. Regional wall motion in the infarct area was determined from left ventricular (LV) cine angiograms using the center-line method. Patients with mild hypokinesis (hypokinesis less than or equal to -2 SD from normal) could be distinguished from those with severe hypokinesis (hypokinesis greater than -2 SD) using the prethrombolysis thallium score with an accuracy of 83%. Accuracy using the post-thrombolysis score was 76%. When the post-thrombolysis thallium and technetium pyrophosphate scores were combined, differentiation was possible in 91% of all patients studied, and in 100% of patients with anterior myocardial infarction. Thus, analysis of combined thallium and technetium pyrophosphate scintigraphy accurately predicts recovery of LV function after thrombolysis and may be helpful in deciding whether acute percutaneous transluminal coronary angioplasty or bypass surgery should be performed after thrombolysis.

Cardiac Output↗
PubMed1988

Immunoscintigraphy with combinations of various monoclonal antibodies--studies on xenografts of human gastrointestinal carcinomas.

In order to investigate whether combinations of monoclonal antibodies (MAbs) allow a more sensitive and valid localisation of tumors by immunoscintigraphy compared to the application of single MAbs we injected 3.7 MBq/animal of various 131I-labelled MAbs (anti-CA 19-9, -CA 125, -CEA, BW 494/32, 431/31) or equivalent combinations thereof into NuNu-Balb-C mice bearing xenografts of human gastrointestinal tumors. In addition, "dose response curves" were calculated in order to evaluate the results for different total doses. As parameters we mainly used quality of the scans, fractional uptake of injected dose and tumor/blood or tumor/organ ratios. The results do not support the concept that "cocktails" of MAbs improve the results of immunoscintigraphy. In contrast, a single MAb should be used for clinical immunoscintigraphy, preferably the most appropriate one according to the results of serum determinations of the corresponding tumor-associated antigens or of immunohistochemistry. Cocktails or consecutive applications of different MAbs for immunoscintigraphy should be restricted to cases without dominant tumor-associated antigen and corresponding MAb, respectively, and to patients in whom a first trial with a first single MAb failed.

Animals↗
PubMed1988

[Radioimmunotherapy of solitary liver metastases using intratumor instillation of 131I-labeled monoclonal antibodies--initial results of a clinical study].

Solitary liver metastases (carcinoembryogenic antigen positive) in two patients suffering from colon carcinoma were multifocally injected with 131I-labelled monoclonal antibodies (131I-MAb) against the carcinoembryogenic antigen (CEA). The 131I activity in the metastases decreased biexponentially. The 131I serum concentration declined triexponentially in patient 1 and monoexponentially in patient 2. The radiation dose to the whole tumor volume amounted to 358 Sv and 762 Sv, respectively; the whole-body radiation dose was 87.5 mSv for patient 1 and 39.0 mSv for patient 2. Complications did not occur. Before treatment there had been a volume doubling time of the metastases of 1.5 and 0.9 months, respectively; this contrasts with a constant tumor volume after treatment as observed over the follow-up period of 3.5 and 2 months, respectively. The CEA serum concentration decreased after 131I-MAb instillation within 1.5 and 2.5 months to 66% and 58%, respectively, when compared with values immediately before treatment. On the basis of these results the intratumoral application of 131I-MAb appears in selected cases to be a suitable method of slowing down growth of liver metastases from gastrointestinal tumors.

Antibodies, Monoclonal↗