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At least 667 records · Page 37Linked to original sources
PubMed1987

The determination of relative kidney function in obstructive uropathy with 99Tcm-DMSA.

In this investigation differential kidney function studies were carried out for eight patients with obstructive uropathy and seven patients who did not suffer from obstruction. The aim of this investigation was to determine whether possible retention of 99Tcm-DMSA in the dilated system would lead to overestimation of the functional mass of an obstructed kidney. The clinical examination took place 4 and 24 h after i.v. injection of the 99Tcm-DMSA. From our results we conclude that this is not a major problem. It appeared that the 4 h values are as reliable as the 24 h values in the clinical situation.

Humans↗
PubMed1987

Relative and absolute 99Tcm-DMSA uptake measurements in normal and obstructed kidneys.

Relative and absolute 99Tcm-DMSA uptake measurements were carried out on 25 adult patients among whom there were 23 normal and 25 malfunctioning kidneys. Data were collected at 3 and 6 h post intravenous tracer injection. Four methods of calculating absolute uptake were investigated and evaluated. These were based on: (1) posterior view and measured kidney depth; (2) posterior view and Raynauld's depth; (3) geometric mean assuming kidney thickness is small enough not to introduce self attenuation of counts in the kidney itself; (4) geometric mean taking kidney thickness into account. Whilst (1) and (2) were found to overestimate and underestimate renal uptake by up to 5 and 14%, respectively, (3) and (4) were found to be more accurate and comparable. The measurement of relative DMSA uptake (right to left) showed no change between the 1 and 6 h measurements for both obstructed and non-obstructed kidneys. Based on the results from method 4, the absolute renal DMSA uptake had a mean value of 25.4%, S.D. 8.9% and 30.0%, S.D. 9.2% at 3 and 6 h, respectively, for normal/non obstructed kidneys. For obstructed kidneys (responding to frusemide), the mean uptake was 23.0%, S.D. 7.2 and 25.6%, S.D. 6.7% at 3 and 6 h, respectively. For obstructed kidneys not responding to frusemide, the mean uptake was 16.8%, S.D. 3.9 and 20.6%, S.D. 4.8% at 3 and 6 h, respectively. No correlation was found between absolute DMSA uptake and degree of renal obstruction.

Adult↗
PubMed1989

Renal imaging with 99Tcm-labelled DMSA in the detection of acute pyelonephritis: an experimental study in the pig.

Serial renal 99Tcm-labelled dimercaptosuccinic acid (DMSA) scintigrams were acquired 2-58 days after the introduction of urinary tract infection in 33 pigs with experimentally induced vesicoureteric reflux (VUR). In 29 animals VUR was unilateral and in four bilateral, a total of 37 refluxing systems. Animals were killed either at varying intervals after a scintigraphic defect was noted (24 refluxing kidneys) or after a period when sequential scintigrams were normal (13 refluxing kidneys). The appearance of the scintigram acquired on the day prior to death was compared with the renal pathology, each kidney and renal image being divided into three zones (upper, middle, lower) for separate consideration. Of the 37 refluxing systems pyelonephritic lesions were seen in 27, in a total of 61 zones. In the remaining ten kidneys no scintigraphic defect was detected and no pathological lesions were identified either macroscopically or microscopically. Where an abnormality was detected on the scintigram a lesion was always identified in the kidney (sensitivity 100%). Small pyelonephritic lesions in a total of 12 zones in six kidneys were not detected on the scintigram (specificity 82%). Of the lesions undetected by scintigraphy only one occurred in the upper pole.

Acute Disease↗
PubMed1989

New tracers for the imaging of the medullary thyroid carcinoma.

I-MIBG and 99Tcm(V)-DMSA have been recently proposed as scintigraphic markers of the medullary thyroid carcinoma (MTC). Thirty two patients were examined with 131I- or 123I-MIBG and 26 of these were re-examined with 99Tcm(V)-DMSA (planar and SPECT). From our experience we can draw the following conclusions: (1) the scintigraphic attempt was useless in patients with normal levels of plasma calcitonin (CT): (2) in patients with high plasma CT levels, the sensitivity of the MIBG was better in familiar (3/3 true positive) than in sporadic disease (7/21 true positive; overall sensitivity = 42%); the 99Tcm(V)-DMSA was positive in 16/19 cases, (overall sensitivity = 84%) even in cases which had been false negative with MIBG (6 patients); (3) no false positive results were found; (4) the scan with 99Tcm(V)-DMSA is then suggested as the first imaging approach during the follow up in patients affected by MTC and still having high levels of plasma CT. The MIBG scan should be limited to the patients in whom the possible use of MIBG therapy has to be investigated.

3-Iodobenzylguanidine↗
PubMed1989

99Tcm-diastereomeric dimercaptosuccinic acid complexes: comparison of their biodistribution.

The biodistribution of two stereoisomeric 99Tcm complexes derived from diastereomeric dimercaptosuccinic acids (DMSA), 99Tcm-dl-DMSA and 99Tcm-meso-DMSA, was examined in sarcoma 180 tumour-bearing mice. The biodistribution pattern of meso-complex was not significantly different from 99Tc(V)m-DMSA, a new tumour imaging agent, while the dl-complex did not show the osteotropic property observed in meso- and 99Tc(V)m-DMSA complexes. The ratio of tumour to blood was superior for the 99Tcm-dl-DMSA (2.68) over the 99Tcm-meso-DMSA (1.25) at 3 h, and the ratio was reversed at 6 h, 3.13 to 4.28. The results indicate that dl-complex is of importance for the possible use in tumour imaging.

Animals↗
PubMed1989

What is the optimal imaging time for 99Tcm-(V)-DMSA planar scintigraphy in the detection of squamous carcinoma? A comparative study in humans and in an animal tumour model.

99Tcm-(V)-DMSA is a new tumour imaging agent which has been used to image squamous cell carcinoma (SCC) of the head and neck. There have been, however, no studies to date evaluating its optimal imaging time for SCC. Seven patients were studied (six SCC; one nontumour) and seven rabbits (six with SCC, (17 tumours); one nontumour). For the human qualitative studies there was a 67% sensitivity at 2, 4 and 6 h with image quality being optimum at 4 h. Maximum quantitative uptake occurred between 2 and 4 h. For the rabbit qualitative studies the optimum imaging time was 4 h (92% sensitivity, 100% specificity) and maximum quantitative uptake occurred at between 1.5 and 5 h. Taking into account the human and rabbit qualitative and quantitative studies combined with the pharmacokinetics and biodistribution of 99Tcm-(V)-DMSA, the optimum imaging time of 99Tcm-(V)-DMSA in humans with SCC was between 2 and 4 h.

Aged↗
PubMed1989

99Tcm-MAG3 for quantitation of differential renal function.

We studied two different methods for the evaluation of differential renal function in a group of 100 patients with various kidney disorders whose effective renal plasma flow (ERPF) had been calculated previously by single 125I-orthoiodohippurate (OIH) injection and multiple blood sampling. Patients were divided into three groups according to their ERPF:ERPF is greater than or equal to 250 ml min-1; ERPF less than or equal to 100 ml min-1; and ERPF greater than 100 ml min-1 and less than 250 ml min-1. The two methods used to assess differential renal function were: first, relative 99Tcm-dimercaptosuccinic acid (DMSA) uptake calculated by normalized background and attenuation corrected cumulative counts in each kidney 24 h p.i.; and second, relative 99Tcm-mercaptoacetyl-triglycine (MAG3) uptake within 1 and 2 min p.i. calculated by normalized background and attenuation corrected counts on each renal area. The results obtained with each method correlated strongly with high significance (p less than 0.0001). In the right kidney, mean values obtained with 99Tcm-MAG3 tend to be higher than mean values obtained with 99Tcm-DMSA.

Adult↗
PubMed1990

99Tcm (v) DMSA and 67Ga-citrate imaging in patients with head and neck squamous carcinoma: a clinical and scintigraphic study.

Technetium-99m (99Tcm) (v) dimercaptosuccinic acid (DMSA) is a new tumour imaging agent which has been used to image medullary carcinoma of the thyroid and squamous cell carcinoma (SCC) of the head and neck. This study was undertaken to compare planar scintigraphy in patients with head and neck SCC using 99Tcm (v) DMSA and the established tumour imaging agent gallium-67 citrate (67Ga). Seventeen patients were studied of whom 16 had a head and neck malignancy. Clinical examination was more sensitive and accurate than 67Ga scintigraphy, which in turn was more sensitive and accurate than 99Tcm (v) DMSA in detecting patients with cancer, patients with primary tumours and patients with metastatic neck carcinoma. Neither 67Ga or 99Tcm (v) DMSA planar scintigraphy has any role to play in the routine evaluation at presentation of patients with head and neck SCC.

Adult↗
PubMed1990

99Tcm (v) DMSA: the pituitary sign.

Technetium-99m (99Tcm) (v) dimercaptosuccinic acid (DMSA) is a new tumour imaging agent which has been used to evaluate head and neck tumours. It has a normal head and neck biodistribution to include the lacrimal glands, nasal mucosa and the blood-pool. Seventy-seven patients were studied of whom 63 had a head and neck malignancy. Of these patients, 19 (25%) exhibited positive accumulation of radioactivity in the region of the pituitary gland and this was a constant finding in those followed-up after treatment. Biodistribution studies in forty New Zealand white rabbits confirmed pituitary accumulation of 99Tcm (v) DMSA. The pituitary gland region should be included in the normal biodistribution of 99Tcm (v) DMSA.

Adult↗
PubMed1990

Pharmacokinetics, biodistribution and dosimetry of 99Tcm(V)DMSA in humans with squamous cell carcinoma.

Technetium-99m (99Tcm)(V) dimercaptosuccinic acid (DMSA) is a new tumour imaging agent which has been used to evaluate squamous carcinoma (SCC) of the head and neck. This study evaluated the pharmacokinetics and biodistribution of 99Tcm(V)DMSA in patients with SCC and calculated the bone mass of a New Zealand White (NZW) rabbit. This data was then used to calculate the effective dose equivalent in man. A total of 16 patients were studied (5 with no tumour, 11 with tumour). 99Tcm(V)DMSA had a fast bi-exponential blood clearance in patients with no tumour (30 and 401 min) and patients with tumour (30 and 387 min) with no significant difference (p greater than 0.05) between the two groups. 99Tcm(V)DMSA had a fast cumulative urine excretion with mean half-times in non-tumour and tumour patients of 183 min and 244 min respectively. There was no significant difference (p greater than 0.05) between these two latter groups. The effective dose equivalent of 99Tcm(V)DMSA in man is 5.1 microSv/MBq.

Aged↗
PubMed1990

Subcellular biodistribution of 99Tcm(V) DMSA in squamous carcinoma: a comparative study in humans and in an animal tumour model.

Technetium-99m(99Tcm) (V) dimercaptosuccinic acid is a new imaging agent which has been used to evaluate head and neck squamous cell carcinoma (SCC). This study compared the subcellular biodistribution of 99Tcm(V)DMSA in an established rabbit tumour SCC model and in humans with head and neck SCC. In rabbits, approximately 17-37% of radioactivity was located on tumour cell membrane. Approximately 57-80% of radioactivity was located nonspecifically in tumour cytosol, only 2-6% was bound specifically to tumour mitochondria, and 1-4% bound specifically to microsomes. In humans, 25-45% of radioactivity was localized on tumour cell membrane and 28-60% localized nonspecifically in tumour cytosol. There was 11-20% of radioactivity specifically bound inside the cell to the mitochondria and 1-6% specifically bound to microsomes. These results show that although 99Tcm(V)DMSA is accumulated at sites of SCC, the localization process is nonspecific.

Aged↗
PubMed1990

Evaluation of renal functional changes after extracorporeal piezoelectric lithotripsy (EPL) by radionuclide studies.

Extracorporeal piezoelectric lithotripsy (EPL) has been recently introduced as a non-invasive method for treatment of renal and gall bladder stones. Thirty seven patients treated with EPL for renal calculi were the subjects of radionuclide renal studies. The aim was to evaluate the effects of EPL as a new technology by radionuclide renography. 99Tcm-DTPA and 99Tcm-DMSA studies were performed pre-EPL and one day and one week post-EPL. Various parameters of the sequential radionuclide studies were evaluated. One day post-EPL, changes in parenchymal transit time index, relative uptake function, glomerular filtration rate, time-activity curves and kidney dimensions were observed. At one week post-EPL, different parameters returned to baseline status in the majority of cases. The study indicates that EPL has a variety of effects on the kidney that could be demonstrated and followed by sequential radionuclide renal studies. Furthermore the study suggests spacing of EPL sessions by approximately one week.

Adult↗
PubMed1992

Kidney depth measured by using 99Tcm-DMSA. Comparison with CAT scan: review of 50 measurements.

Measurement of kidney depths using computed axial tomographic (CAT) scans, considered as the gold standard, has been compared in 25 patients with depth measured using an isotopic method (99Tcm-DMSA). 99Tcm-DMSA underestimates renal depth in 78% of the cases (mean underestimation: 0.78 cm). The correlation coefficient between the two methods is 0.82. As a comparison, kidney depths calculated using Tonnesen's formula are also given and related to CAT scan results. The presence of renal morphological abnormalities in 18% of the studied kidneys allowed the authors to study their potential influence on 99TcmDMSA measurements. They do not seem to be very different from those obtained in morphologically normal kidneys. The different methods for kidney depth measurement described in the literature are briefly reviewed.

Adult↗
PubMed1992

Replacing 99Tcm-DMSA for renal imaging?

We have tried to evaluate the usefulness of an early 99Tcm-MAG3 image, obtained during the second minute after injection of the tracer, in predicting the renal alterations seen on a 99Tcm-DMSA scintigraph, in children clinically suspected of pyelonephritis. It appears that the accuracy of the MAG3 image is population dependent: when, in most of the patients of a study group, DMSA scintigraphy is either normal or very abnormal, the MAG3 image will correctly reflect the DMSA scintigraph. However, when the DMSA alterations are less pronounced, the early MAG3 image will miss the lesions in about 50% of the cases.

Acute Disease↗
PubMed1993

Comparison of planar and SPECT 99Tcm-DMSA scintigraphy for the detection of renal cortical defects in children.

Renal cortical scintigraphy with 99Tcm-dimercaptosuccinic acid is an excellent imaging modality for the detection of renal cortical defects in children presenting with vesicoureteric reflux and urinary tract infections. Single photon emission computed tomography (SPECT) has proven increased sensitivity over planar scintigraphy for lesion detection in the heart, liver and brain. However, its role in the evaluation of renal cortical defects compared to planar scintigraphy has not been fully assessed. We wished to determine whether SPECT increases the sensitivity for detecting renal cortical defects in children compared to high-resolution planar scintigraphy. Forty-one children (90 renal units) with underlying vesicoureteric reflux and/or recently treated urinary tract infection (UTI) were evaluated. There was no statistically significant difference in the number of defects detected between a single-head SPECT system and high-resolution planar scintigraphy, 24 and 20, respectively (P = 0.54). There were four defects detected by SPECT not reported by planar scintigraphy; two of these were only seen retrospectively on planar scintigraphy. There were two children with renal cortical defects detected by SPECT and not by planar scintigraphy. All defects defected by planar scintigraphy were detected by SPECT. It is concluded that although the risk of missing renal cortical defects is low when using high-resolution, three-view planar scintigraphy, SPECT should be employed whenever feasible. Single photon emission computed tomography detected renal cortical defects in children not diagnosed by planar scintigraphy and hence patient management may be altered.

Child↗
PubMed1993

Studies on the preparation and isomeric composition of 186Re- and 188Re-pentavalent rhenium dimercaptosuccinic acid complex.

The preparative conditions for 186Re(V)DMSA and 188Re(V)DMSA (DMSA = meso-dimercaptosuccinic acid), beta-emitting radiopharmaceuticals that have been shown to localize in medullary thyroid carcinoma, require modification depending on the amount of carrier rhenium and the chemical form and medium in which the rhenium is supplied. Preparative conditions are described for use with carrier-free 188ReO4- in saline, and for use with 186ReO4- in saline, sodium hydroxide or nitric acid. Preparation of 186Re(V)DMSA (carrier present up to 2 mg per 2.5 ml reaction volume) requires a DMSA:SnCl2:Re ratio of 10:5:1 at 100 degrees C for 30 min. Addition of excess nitric acid or hydrochloric acid up to a concentration of 155 mM does not reduce the yield from 100%. A commercial DMSA kit vial (e.g. Amerscan DMSA) can be used for preparation of 188Re(V)DMSA (carrier free) provided the required activity is in a volume of less than 1 ml per vial. A convenient method of concentrating the 188Re generator eluate to the required volume is described.

Isomerism↗