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H Jacobsson

Publications and source records attributed to H Jacobsson.

At least 91 records · Page 5Linked to original sources
PubMed1995

A 3-D method for delineation of activity distributions and assessment of functional organ volumes with SPECT.

The distribution volume of an organ may have a clinical impact in many cases and various methods have been designed to make volume assessments. In this paper, we describe a new method for delineation of the distribution outline and volume determination. The method is based on smoothing, differentiation, image relaxation and voxel counting of single photon emission computer tomography (SPECT) image sets with 3-D operators. A special routine corrects for the inherent thickness of the voxel-based outline. Phantom experiments, using a SPECT system with LEGP-collimator and a 64 x 64 acquisition matrix with 6.3 x 6.3 mm2 pixel size, demonstrated good correlation between the measured and the true volumes. For volumes larger than 120 cc the correlation coefficient was 0.9999 with SE 1.0 cc and an average relative deviation of 0.49%. For volumes below 120 cc, the accuracy was impaired due to low resolution power. By improving the system spatial resolution with an LEHR-collimator and a smaller pixel-size (4.1 x 4.1 mm2), good accuracy was achieved also for volumes in the range from 3 to 120 cc. Measurements of 15 differently shaped phantoms of volumes between 3 and 104 cc demonstrated high correlation between measured and true volumes: R = 0.9921 and SE = 0.74 cc (5.3%). For volumes as small as 3 and 5 cc, the difference between the true and the assessed volume was 0.6 cc. The reproducibility of the method was within 3% for volumes above 120 cc and within 7% for volumes below.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗
PubMed1994

Technetium-99m methoxyisobutylisonitrile localizes an ectopic ACTH-producing tumour: case report and review of the literature.

Extensive investigation including whole-body examinations with computed tomography and magnetic resonance imaging did not detect the suspected ectopic ACTH-producing tumour in a patient with advanced Cushing's syndrome and hypokalemic alkalosis. Gamma camera examination with technetium-99m methoxyisobutylisonitrile (MIBI) depicted the tumour, which was localized in the anterior neck and mediastinum. This was later verified by surgery. 99mTc-MIBI is normally used for myocardial scintigraphy. Its accumulation is unspecific and merely reflects metabolic activity. Despite this, the present case shows that examination with this agent can provide important information with regard to tumour localization in a given situation, thereby serving as a complement to other imaging modalities. The current literature on 99mTc-MIBI for tumour diagnosis is reviewed.

ACTH Syndrome, Ectopic↗
PubMed1994

In vivo dynamical distribution of 131I-VIP in the rat studied by gamma-camera.

The in vivo distribution of vasoactive intestinal peptide (VIP) was studied for the first time using a rat model in combination with labeled VIP (131I-VIP) and a gamma-camera. A dynamic scan showed that 131I-VIP was cleared rapidly from the blood circulation. The radioactivity was taken up and accumulated in the lungs during the first minute. During the next 15 min, the radioactivity was slowly removed from the lungs and redistributed into the kidneys, gastric mucosa, liver and small intestine. However, the radioactivity extracted by the lungs was about 6-fold lower during the first minute when a large amount of the non iodinated VIP was coinjected with the 131I-VIP. 131I-VIP was eliminated rapidly from the blood with a half-life of 0.44 +/- 0.05 (min +/- SD) while in lung the elimination half-life was determined to 2.3 +/- 0.8 (min +/- SD). Of the radioactivity in the lungs, 2% was found to be intact 131I-VIP after 20 min. In all other organs the radioactivity found was assumed to be low molecular weight fragments of 131I-VIP. We suggest that lungs play an important role to extract VIP from the circulation after an i.v. administration. 131I-VIP degradation products are redistributed mostly to the kidneys and to the gastric mucosa to be excreted through urine and stomach contents, respectively.

Animals↗
PubMed1994

Change in size, shape and radiocolloid uptake of the alcoholic liver during alcohol withdrawal, as demonstrated by single photon emission computed tomography.

The volume of the total liver and separate right and left lobes was studied before and after 1 week of alcohol withdrawal in 16 consecutive alcoholics by means of single photon emission computed tomography after intravenous injection of 99Tcm-human albumin colloid; the relative tissue distribution of radioactivity was also followed. The left liver lobe increased in volume more than the right lobe during drinking and decreased more rapidly after alcohol withdrawal. Median volume reductions during 1 week of alcohol withdrawal were: total liver 12%, left lobe 26%, and right lobe 8%, indicating that half of the reduction to values of a control group was achieved during this first week. The volume of the right but not of the left lobe was significantly correlated to body size in alcoholics and in controls. The left lobe had a lower capacity to concentrate the radiocolloid than the right lobe in alcoholics and in controls. The liver/spleen, liver/bone marrow and liver/background radioactivity concentration ratios in the alcoholics increased during alcohol withdrawal. We conclude that heavy drinking causes both an increased total liver volume and a change in liver shape, with a relatively more enlarged left than right lobe, as well as a decreased capacity to concentrate radiocolloid. These changes are rapidly reversible during abstinence from alcohol.

Adult↗
PubMed1994

Disturbances of fluid balance reduce the image quality of bone scintigraphy. Experimental studies in mice.

The effects of hydration, dehydration and osmotic diuresis on the activity distribution of bone-seeking radiopharmaceuticals have been studied in an experimental mouse system. It was found that any change of the water balance impairs the activity distribution of the radiolabelled phosphonate in the potential bone scintigraphic image. The findings suggest that in order to maintain image quality, elderly patients should not be instructed to drink a large volume of fluid after the administration of a bone-seeking radiopharmaceutical. Further investigations, though, have to be performed in humans.

Animals↗
PubMed1994

A combined method for quantitative pertechnetate scintigraphy in the diagnosis of sacroiliitis. A controlled study.

A simplified scintigraphic technique for the assessment of sacroiliitis is described. It is based on the fact that an inflamed joint shows increased perfusion activity after administration of sodium pertechnetate. The sacroiliac joints are located by injection of a small amount of bone-seeking activity. Thereafter the pertechnetate activity is injected and the bone-seeking activity subtracted. The perfusion (pertechnetate) activity of the sacro-iliac joints is related to the activity of the large vessels of the thigh. Normal values have been established based on a study of 39 healthy controls. The method has been applied to 2 groups of patients with clinical sacroiliitis, one with and one without radiographical signs of sacroiliitis. The patients with radiographically verified sacroiliitis showed significantly higher values than the controls. The technique offers a high specificity and a high positive predictive value.

Adolescent↗
PubMed1993

Cholescintigraphy in the diagnosis and assessment of benign papillary stenosis.

Benign papillary stenosis (BPS) is an uncommon condition, the diagnosis of which is often difficult. In this report cholescintigraphy with technetium-99m diethyl-acetanilido-iminodiacetic acid has been evaluated for the diagnosis of BPS, as well as for assessing the effect of treatment by endoscopic sphincterotomy (ES). In 12 patients with BPS, cholescintigraphy was performed before and after ES and the findings compared with those in ten controls. Time-activity curves from regions over the liver and bowel were generated. A significant difference was found in respect of the time for maximum activity (Tmax) over the liver before and after ES. The time for occurrence of bowel activity (Texcr) also showed significant differences before and after ES. Considering both Tmax and Texcr mean values plus two standard deviations in the control group, all BPS patients would have been detected and there would have been no false-positives among the controls. It is concluded that cholescintigraphy should be used in the diagnosis of BPS. The method has high sensitivity and should be applied as an early diagnostic procedure to exclude BPS in patients with clinical suspicion of the disorder. The method can also be used for assessment of endoscopic treatment (ES).

Aged↗
PubMed1993

Route of administration may determine the biological effects of RU 41,740 (Biostim). Trapping of 99mTc-labelled human albumin colloids in mice.

Experiments have been conducted in mice to examine whether treatment with the immunostimulating drug RU 41,740 (Biostim) may change the distribution of i.v. injected radiolabelled human albumin colloids. It was observed that a single i.p. injection of Biostim (1 ng-1000 micrograms) significantly enhanced trapping of the particles in spleen and lungs. The effect, which was dose-dependent, was most pronounced in the lungs where more than a 10-fold increase could take place. On the contrary, oral administration of Biostim caused a dose-dependent decrease of colloid trapping in the lungs. Further experiments showed that oral administration of Biostim resulted in the appearance of soluble factors in the blood which inhibited the phagocytic activity of lung macrophages, for example, sera from such mice inhibited lung colloid trapping when injected into new hosts. I.p. administration of Biostim, however, resulted in the appearance of factors in the blood which enhanced phagocytosis of lung macrophages. Our conclusion is that the biological activity of Biostim in vivo may be highly dependent on its route of administration.

Adjuvants, Immunologic↗
PubMed1993

Can pharmacological intervention improve the visualization of the reticuloendothelial system using 99mTc-labeled albumin nanocolloid to that achievable with 111In-labeled granulocytes? Experimental studies in mice.

The use of 99mTc-colloids for bone marrow scintigraphy is limited by a high liver uptake, which hampers the evaluation of surrounding skeletal structures. In an experimental mouse system, different measures to increase the bone marrow activity in relation to the liver activity have been tested. A slightly positive, but significant, outcome was achieved by three different measures, namely fasting, pretreatment with a calcium-blocking pharmaceutical (Nimodipine) and pretreatment with large amounts of a gelatine colloid. It is concluded that the possibilities of dramatically improving the bone marrow uptake of a colloid compared to the liver are limited and not comparable to that achievable using radiolabeled granulocytes.

Animals↗
PubMed1993

A better target-to-background activity ratio using a large-sized colloid compared to a nano-sized colloid for scintigraphy of the peripheral bone marrow. A study in mice and humans.

Small-sized radiocolloids with a diameter less than 100 nm (nanocolloids), reduce the confounding liver and spleen uptake compared to large-sized colloids at bone marrow scintigraphy. Consequently, nanocolloids are today generally used for this purpose. Such colloids, though, seem to produce considerable background activity, especially from the large vessels and the urinary tract. This has been studied in mice and humans using a nanocolloid and a large-sized colloid, both composed of human albumin. In mice, the findings confirm a lower relative and absolute uptake of the nanocolloid in the liver and spleen compared to the large-sized colloid, whereas the bone marrow activity relative to the activity of kidneys, heart, lungs, intestines and peripheral blood is higher for the large-sized colloid than for the nanocolloid. The latter was confirmed in humans who were examined by single photon emission computed tomography corrected for attenuation and scattering of photons. It is concluded that a large-sized colloid should be used for spot examination of a specific marrow region outside the liver and spleen, while a nanocolloid must be used when examining structures close to the liver and spleen as well as for depiction of the entire bone marrow.

Animals↗
PubMed1992

Determination of functional kidney volume by single-photon emission computed tomography in patients with insulin-dependent diabetes mellitus.

Functional parenchymal kidney volume was determined by single-photon emission computed tomography (SPECT) for 99mTc-dimercaptosuccinic acid (DMSA) using a rotating gamma camera in phantom experiments and in patients with insulin-dependent diabetes mellitus (IDDM). The results from the patient examinations were corrected according to the phantom studies and were thereafter set in relation to renal haemodynamics, blood pressure, and urinary albumin excretion. Functional parenchymal kidney volume was significantly greater in diabetic patients compared to that of 11 healthy controls (P < 0.003). Urinary albumin excretion was increased and glomerular filtration rate (GFR) per renal parenchymal volume significantly less in patients with a duration of diabetic disease of more than 15 years compared to patients with shorter duration of disease (P < 0.03 and P < 0.05 respectively). Diabetic patients with a GFR of more than 120 ml/min had greater renal parenchymal volume than patients with lower GFR (P < 0.02). Patients with increased GFR, renal plasma flow (RPF), renal blood flow, or filtration fraction had significantly greater functional parenchymal volume than the healthy subjects (P < 0.01 for all comparisons). We conclude that by application of SPECT for DMSA we were able to show that IDDM patients have greater renal parenchymal volumes than healthy subjects. GFR/kidney volume was increased in IDDM patients with a duration of disease of < 15 years compared to patients with long-standing diabetes. The SPECT technique seems suitable for prospective long-term follow-up studies of functional kidney volume in IDDM patients.

Adult↗
PubMed1991

Radiological detection of bone and bone marrow metastases.

Bone scintigraphy is the primary method for the diagnosis of skeletal metastases. This investigation is sensitive, but the interpretation must be performed in the knowledge that it is also nonspecific. Despite this, a correct diagnosis can usually be achieved. The first-hand supplementary investigation, after a doubtful scintigraphic finding, is radiography. In most cases this is sufficient for a diagnosis. When a scintigraphic abnormality cannot be adequately explained, usually because of a negative radiographic examination, a more sensitive modality must be used. Computerized tomography offers increased sensitivity and specificity, and is primarily used for this purpose. In this way contrast resolution is increased and problems caused by obscuring tissue and complicated anatomy are reduced. Since bone metastases migrate via the active bone marrow an alternative supplementary investigation is bone marrow scintigraphy. Its usefulness is restricted by disturbing activity, from the liver and the spleen, which obscures a significant part of the active marrow, and by the fact that a lesion must be of a certain size to become apparent. Magnetic resonance imaging yields excellent images of the extension of a tumor in soft tissue. Owing to high costs and restricted availability it is still mainly used for preoperative location of metastases.

Bone Marrow↗
PubMed1991

Reduced incidence of bone metastases in irradiated areas after external radiation therapy of prostatic carcinoma.

Fourteen males, out of 380 patients, treated with radiation to the central pelvis and lumbar spine for poorly differentiated prostatic carcinoma were analyzed in retrospect. The dose of radiation to the bones of the target area was 5,000 cGy. The patients showed no signs of metastases at bone scintigraphy performed in connection with the treatment. In an average of 34 months after finishing radiotherapy, the patients developed metastases at bone scintigraphy. The pattern was similar in all patients. The treated target area appeared as a "cold zone" surrounded by more or less homogenously and strongly increased activity of the axial skeleton, characteristic of bone metastases. Radiography, which was performed in 11 patients, confirmed widespread metastatic disease sparing the target area. This was interpretated as bone metastasis being precluded by the irradiation. The most probable explanation of this finding is eradication in situ of distant micrometastases already present in the bone marrow at the time of treatment. An alternate explanation is a reduced implantation of later seeded blood-born metastases as an effect of the irradiation. The characteristic pattern of this phenomenon must be recognized at bone scintigraphy.

Aged↗
PubMed1991

Effect of size fractionation on the distribution of an albumin colloid in the reticuloendothelial system of the mouse.

To study if by varying the particle size of a 99mTc albumin colloid preparation its relative bone marrow accumulation could be increased, it was separated by gel filtration and different fractions were injected into mice. Particles around and smaller than the peak size of the colloid, 31 nm, exhibited a higher bone marrow/liver-spleen uptake ratio than larger particles but the uptake ratio was similar to that of the unseparated colloid. An antimony sulphide colloid showed a similar particle size distribution, but the corresponding uptake ratio was half of the albumin colloid. This indicates that characteristics other than size determine the distribution of a colloid in the reticuloendothelial system.

Animals↗
PubMed1991

DNA as a prognostic marker in advanced high-grade prostatic cancer. A preliminary report. SPCG-I study.

This is a presentation of some preliminary data from SPCG-I, a multicenter study started in 1984 by the Scandinavian Prostatic Cancer Group. It is a randomized double-blind study comparing estramustine phosphate and diethylstilbestrol in the primary treatment of 195 patients with T1-4, NX, M1, G2-3 prostatic cancer. The code is not yet broken. This presentation describes the impact of the pretreatment parameters performance status, pain, tumor burden, grade and DNA-ploidy of the prostate tumor, on time to progression and overall survival. DNA studies have so far only been completed in 66 of the 195 patients. For the whole group of 195 patients, pain (p less than 0.004) and tumor grade (p less than 0.02) had the most significant impact on time to progression, and performance status (p less than 0.01) and grade (p less than 0.03) on overall survival. In the small group of 66 patients where the DNA pattern of the primary tumor was evaluated, no parameter had any significant correlation to time to progression and overall survival. This study is still continuing.

DNA, Neoplasm↗
PubMed1991

Vesicoureteral reflux in adults studied by computerized radionuclide cystography.

Direct radionuclide cystography in a computerized method as described by Willi and Treves was used in adults with recurrent pyelitis but without evidence of obstruction. Reflux was observed in 15 out of 38 patients. In patients with neurogenic bladder dysfunction or megaureters, reflux began early during the bladder filling and attained higher volumes than in those with uncomplicated pyelitis, who had minor reflux appearing mainly during voiding. Bladder capacity and detrusor compliance were lower in patients with reflux than in those without reflux. The low radiation exposure in radionuclide cystography permits observation of the urodynamic course of urinary reflux and correlation to the intravesical volume and pressure. The method is sensitive, and minor refluxed volumes can be detected. Radionuclide cystography can therefore be recommended for checking of surgical results and for follow-up of patients with neurogenic bladder dysfunction.

Adolescent↗