Risk of recurrent laryngeal nerve palsy in patients undergoing thyroidectomy with and without intraoperative nerve monitoring.

BACKGROUND: Vocal cord palsy occurs in 3-5 per cent of patients after thyroidectomy. To reduce this complication, intraoperative nerve monitoring (IONM) has been introduced, although its use remains controversial. This study investigated the risk of postoperative vocal cord palsy with and without the use of intermittent IONM. METHODS: Patients registered in the Scandinavian Quality Register for Thyroid, Parathyroid and Adrenal Surgery, 2009-2013, were included. Early palsy of the recurrent laryngeal nerve was diagnosed within 6 weeks after surgery. Permanent palsy was defined as that persisting after 6 months. Univariable and multivariable logistic regression analyses were used to examine risk factors for vocal cord palsy. RESULTS: The cohort consisted of 5252 patients undergoing thyroidectomy. IONM was used in 3277 operations (62·4 per cent); postoperative laryngoscopy was performed in 1757 patients (33·5 per cent). Early vocal cord palsy occurred in 217 patients (4·1 per cent), of which three were bilateral, all in the group without IONM. Permanent vocal cord palsy occurred in 62 patients (1·2 per cent). In the multivariable analysis of 1757 patients who had postoperative laryngoscopy, the use of IONM was not associated with a decreased risk of early vocal cord palsy (odds ratio (OR) 0·67, 95 per cent c.i. 0·44 to 1·01), but decreased the risk of permanent vocal cord palsy (OR 0·43, 0·19 to 0·93). [Correction added on 11 November 2016 after first publication: the word 'routine' has been removed from this section.] CONCLUSION: IONM reduced the risk of permanent vocal cord palsy. No bilateral recurrent laryngeal nerve injury occurred following IONM.

Gray matter volume alterations related to trait dissociation in PTSD and traumatized controls.

OBJECTIVE: This study used voxel-based morphometry (VBM) to investigate brain structural alterations related to trait dissociation and its relationship with post-traumatic stress disorder (PTSD). METHOD: Thirty-two subjects either developing (N = 15) or non-developing (N = 17) PTSD underwent MRI scanning and were assessed with the Dissociative Experience Scale (DES), subscales for pathological (DES-T) and non-pathological trait (DES-A) dissociation, and other clinical measures. Gray matter volume (GMV) was analyzed using VBM as implemented in SPM. PTSD and non-PTSD subjects were compared to assess brain alterations related to PTSD pathology, whereas correlation analyses between dissociation measures and GMV were performed on the whole sample (N = 32), irrespective of PTSD diagnosis, to identify alterations related to trait dissociation. RESULTS: As compared to traumatized controls, PTSD subjects showed reduced GMV in the prefrontal cortex, hippocampus and lingual gyrus. Correlations with dissociation measures (DES, DES-T, and DES-A) consistently showed increased GMV in the medial and lateral prefrontal, orbitofrontal, parahippocampal, temporal polar, and inferior parietal cortices. CONCLUSION: PTSD and dissociation seem to be associated with opposite volumetric patterns in the prefrontal cortex. Trait dissociation appears to involve increased GMV in prefrontal, paralimbic, and parietal cortices, with negligible differences between pathological and non-pathological dissociation.

The initial change in tumor size predicts response and survival in patients with metastatic colorectal cancer treated with combination chemotherapy.

BACKGROUND: To determine whether the change in tumor diameters at the first follow-up computed tomography (CT) examination after baseline examination (first change) correlates with outcome in patients with metastatic colorectal cancer (mCRC) treated with combination chemotherapy. PATIENTS AND METHODS: The first change was analyzed in a multicenter randomized phase III trial (Nordic VI, N = 567) comparing first-line irinotecan with either bolus or infused 5-fluorouracil. Cox proportional hazards multiple regression model and Kaplan-Meier survival analyses after correction for guarantee-time bias were carried out to evaluate correlations between first change, objective response according to RECIST 1.0, progression-free survival (PFS), and overall survival (OS). RESULTS: The hazard ratios for PFS and OS decreased along with first change. A decrease between 10% and <30%, albeit RECIST does not regard this as a partial response, was a positive prognostic factor for PFS and OS. Patients who had new lesions or unequivocal progression of nonmeasurable lesions had a worse prognosis than those with only an increase in size of >20%. CONCLUSIONS: The change in tumor size at the first follow-up CT is strongly prognostic for PFS and OS in mCRC.

Minimal transmission of HIV despite persistently high transmission of hepatitis C virus in a Swedish needle exchange program.

The aim of this study was to examine the prevalence and incidence of HIV and hepatitis B and C (HBV and HCV) among injecting drug users in a Swedish needle exchange programme (NEP) and to identify risk factors for blood-borne transmission. A series of serum samples from NEP participants enrolled from 1997 to 2005 were tested for markers of HIV, HBV and HCV (including retrospective testing for HCV RNA in the last anti-HCV-negative sample from each anti-HCV seroconverter). Prevalence and incidence were correlated with self-reported baseline characteristics. Among 831 participants available for follow-up, one was HIV positive at baseline and two seroconverted to anti-HIV during the follow-up of 2433 HIV-negative person-years [incidence 0.08 per 100 person-years at risk (pyr); compared to 0.0 in a previous assessment of the same NEP covering 1990-1993]. The corresponding values for HBV were 3.4/100 pyr (1990-1993: 11.7) and for HCV 38.3/100 pyr (1990-1993: 27.3). HCV seroconversions occurred mostly during the first year after NEP enrolment. Of the 332 cases testing anti-HCV negative at enrolment, 37 were positive for HCV RNA in the same baseline sample (adjusted HCV incidence 31.5/100 pyr). HCV seroconversion during follow-up was significantly associated with mixed injection use of amphetamine and heroin, and a history of incarceration at baseline. In this NEP setting, HIV prevalence and incidence remained low and HBV incidence declined because of vaccination, but transmission of HCV was persistently high. HCV RNA testing in anti-HCV-negative NEP participants led to more accurate identification of timepoints for transmission.

Self-rating scales assessing subjective well-being and distress correlate with rCBF in PTSD-sensitive regions.

BACKGROUND: The aim of this study was to investigate the distribution of the regional cerebral blood flow (rCBF) in occupational-related post-traumatic stress disorder (PTSD) subjects and to seek possible correlations between brain perfusion and self-rating scales (SRS) in order to cross-check their diagnostic value and to look for their neural correlates. METHOD: A total of 13 traumatized underground and long-distance train drivers developing (S) and 17 not developing (NS) PTSD who had experienced a 'person under train' accident or who had been assaulted at work underwent clinical assessment and 99mTc-HMPAO SPECT imaging during autobiographical trauma scripts. Statistical parametric mapping was applied to analyse rCBF changes in S as compared with NS and to search for correlations between rCBF and the administered SRS scores, modelling age, months to SPECT and the ratio 'grey matter/intra-cranial volume' as nuisance variables. RESULTS: Significantly higher activity was observed during trauma script in left posterior and anterior insula, posterior cingulate, inferior parietal lobule, precuneus, caudate and putamen in PTSD subjects as compared with the trauma-exposed control group. Impact of Event Scale and World Health Organisation (10) Well-Being Index scores highly correlated with tracer uptake to a great extent in the same regions in which rCBF differences between S and NS were found. CONCLUSIONS: These findings support the involvement of insular, cingulate and parietal cortices (as well as the basal ganglia) in the pathogenesis of PTSD and in the processing of related subjective well-being and distress.

Early prediction of response to first-line chemotherapy by sequential [18F]-2-fluoro-2-deoxy-D-glucose positron emission tomography in patients with advanced colorectal cancer.

BACKGROUND: To evaluate [(18)F]-2-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET), for early evaluation of response to palliative chemotherapy and for prediction of long-term outcome, in patients with metastatic colorectal cancer (mCRC). PATIENTS AND METHODS: In a randomized trial, patients with mCRC received irinotecan-based combination chemotherapy. FDG-PET was carried out before treatment and after two cycles in 51 patients at two centers. Visual changes in tumor FDG uptake and changes measured semi-automatically, as standard uptake values (SUVs), were compared with radiological response after four and eight cycles. RESULTS: The mean baseline SUV for all tumor lesions per patient was higher in nonresponders than in responders (mean 7.4 versus 5.6, P = 0.02). There was a strong correlation between metabolic response (changes in SUV) and objective response (r = 0.57, P = 0.00001), with a sensitivity of 77% and a specificity of 76%. There was no significant correlation between metabolic response and time to progression (P = 0.5) or overall survival (P = 0.1). CONCLUSIONS: Although metabolic response assessed by FDG-PET reflects radiological tumor volume changes, the sensitivity and specificity are too low to support the routine use of PET in mCRC. Furthermore, PET failed to reflect long-term outcome and can, thus, not be used as surrogate end point for hard endpoint benefit.

The role of adrenal scintigraphy in the preoperative management of primary aldosteronism.

BACKGROUND AND AIMS: Differentiation between the two major subgroups of primary aldosteronism, bilateral hyperplasia and aldosterone producing adenoma is essential since therapy in the former is medical and in the latter surgical. The aim of the present study was to evaluate the clinical utility of adrenocortical scintigraphy in the management of primary aldosteronism. MATERIAL AND METHODS: [131I] norcholesterol (NP-59) scintigraphy with dexamethasone suppression for subclassification and lateralization of primary aldosteronism was evaluated in 49 patients with long-term follow-up after diagnosis and treatment. RESULTS: Thirty-three patients with the diagnosis of aldosterone producing adenoma were operated with adrenalectomy. Preoperative scintigraphy showed lateralized isotope uptake in 27/33 patients while 6 showed no uptake. Twenty-two were cured and three significantly improved. Thus, in 25/33 (76%), scintigraphy showed the correct side as the patients benefited of surgery. Two patients did not improve. Fourteen patients with a probable diagnosis of bilateral hyperplasia had normal scintigraphies. CONCLUSIONS: In the present retrospective study we found limited sensitivity of NP-59 scintigraphy. However, when a lateralized scintigraphic uptake is achieved it has a high accuracy. Scintigraphy may be used as an adjunct in cases where adrenal venous sampling is inconclusive.

Operation for primary hyperparathyroidism: the new versus the old order. A randomised controlled trial of preoperative localisation.

BACKGROUND AND AIMS: In patients with primary hyperparathyroidism (PHPT), parathyroid imaging is nowadays routinely used for the purpose to perform a focused unilateral minimally invasive operation. The outcome of this new strategy has, however, not been established in randomised trials. MATERIAL AND METHODS: Patients were randomised to either preoperative localisation with sestamibi scintigraphy and ultrasonography (group I) or no preoperative localisation (group II). In group I, a minimally invasive parathyroidectomy was performed in patients in whom both localisation studies were consistent with a single pathological gland, whereas a conventional bilateral neck exploration was performed in cases with negative localisation findings. In group II all patients underwent conventional bilateral neck exploration. Primary outcome measure was normocalcaemia at 6 months postoperatively. RESULTS: In the preoperative localisation group (group I) 23/50 (46%) of the patients could be operated on with the focused operation whereas 26/50 (52%) were operated on by bilateral neck exploration. All patients in the no localisation group (group II; n = 50) were operated on with the intended bilateral neck operation. Normocalcaemia was obtained in 96% and 94% in group I and II, respectively. Total (localisation and operative) costs were 21% higher in group I. CONCLUSIONS: Routine preoperative localisation, with the intention to perform minimally invasive parathyroidectomy, is not cost effective if concordant results of scintigraphy and ultrasonography are a prerequisite for the focused operation. Less than half of the patients were successfully managed with this strategy, at a higher cost and without obtaining a more favourable clinical outcome.

Vaccination against hepatitis B virus among people who inject drugs - A 20year experience from a Swedish needle exchange program.

BACKGROUND: People who inject drugs (PWID) are at particular risk of hepatitis B virus (HBV) acquisition, but often have poor access or adherence to HBV vaccination. Vaccination against HBV has been offered at a major Swedish needle exchange program (NEP) since 1994. The aim of this study was to evaluate vaccine completion and response rates, and the effect of sequential booster doses to non-responders to the standard vaccination schedule. METHODS: PWID enrolled in the NEP 1994-2013, without serological markers for HBV at baseline (negative for HBsAg/anti-HBc/anti-HBs), were offered a three-dose standard intramuscular vaccination schedule (Engerix®-B, GSK, 20µg/mL, intended to be received at months 0, 1 and 6). Vaccination response was defined as protective levels of anti-HBs (⩾10mIU/mL). Up to three booster doses were then offered for non-responders, each followed by anti-HBs testing. RESULTS: HBV data was available for 2352 identifiable individuals at NEP enrolment, of whom 1516 (64.5%) had no markers for previous HBV exposure or vaccination. Vaccination was initiated for 1142 (75.3%) individuals and 898 (59.2%) completed the standard vaccination schedule. Post-vaccination anti-HBs levels were available from 800 individuals, with 598 (74.8%) responding to the basic vaccination schedule. After up to three booster doses a total of 676 (84.5%) individuals achieved protective anti-HBs levels. Non-response to vaccination was associated with higher age and anti-HCV positivity (p<0.001). Eighteen incident cases of HBV infection were observed among vaccine non-responders, as well as 30 cases among those who had not completed vaccination. CONCLUSION: We demonstrate the feasibility of including HBV vaccination in the services offered by a NEP, with completion of vaccination in a majority of HBV-susceptible PWID. The response to HBV vaccination among PWID was relatively low; however, the addition of up to three booster doses improved the response rate from 74.8 to 84.5%.

Ghrelin stimulates gastric emptying and hunger in normal-weight humans.

CONTEXT: Ghrelin is produced primarily by enteroendocrine cells in the gastric mucosa and increases gastric emptying in patients with gastroparesis. MAIN OBJECTIVE: The objective of the study was to evaluate the effect of ghrelin on gastric emptying, appetite, and postprandial hormone secretion in normal volunteers. DESIGN: This was a randomized, double-blind, crossover study. SUBJECTS: Subjects included normal human volunteers and patients with GH deficiency. INTERVENTION: Intervention included saline or ghrelin (10 pmol/kg.min) infusion for 180 min after intake of a radioactively labeled omelette (310 kcal) or GH substitution in GH-deficient patients. MAIN OUTCOME MEASURES: Measures consisted of gastric empty-ing parameters and postprandial plasma levels of ghrelin, cholecystokinin, glucagon-like peptide-1, peptide YY, and motilin. RESULTS: The emptying rate was significantly faster for ghrelin (1.26 +/- 0.1% per minute), compared with saline (0.83% per minute) (P < 0.001). The lag phase (16.2 +/- 2.2 and 26.5 +/- 3.8 min) and half-emptying time (49.4 +/- 3.9 and 75.6 +/- 4.9 min) of solid gastric emptying were shorter during ghrelin infusion, compared with infusion of saline (P < 0.001). The postprandial peak in plasma concentration for cholecystokinin and glucagon-like peptide-1 occurred earlier and was higher during ghrelin infusion. There was no significant effect of ghrelin on plasma motilin or peptide YY. There was no difference in gastric emptying before and after GH substitution. CONCLUSION: Our results demonstrate that ghrelin increases the gastric emptying rate in normal humans. The effect does not seem to be mediated via GH or motilin but may be mediated by the vagal nerve or directly on ghrelin receptors in the stomach. Ghrelin receptor agonists may have a role as prokinetic agents.

A role for pancreatic polypeptide in the regulation of gastric emptying and short-term metabolic control.

CONTEXT: Previous studies using pancreatic polypeptide (PP) infusions in humans have failed to show an effect on gastric emptying, glucose metabolism, and insulin secretion. This might be due to the use of nonhuman sequences of the peptide. OBJECTIVE: The objective of this study was to use synthetic human PP to study gastric emptying rates of a solid meal and postprandial hormone secretion and glucose disposal as well as the gastric emptying rate of water. DESIGN: This was a single-blind study. SETTING: The study was performed at a university hospital. PARTICIPANTS: Fourteen healthy adult subjects were studied. INTERVENTIONS: Infusion of saline or PP at 0.75 or 2.25 pmol/kg.min was given to eight subjects (gastric emptying of solid food), and infusion of saline or PP at 2.25 pmol/kg.min was given to six subjects (gastric emptying of water). MAIN OUTCOME MEASURES: The main outcome measures were gastric emptying of solids (scintigraphy), hunger ratings (visual analog scale), and plasma concentrations of PP, insulin, glucagon, somatostatin, glucagon-like peptide 1, glucose, and gastric emptying of plain water (scintigraphy). RESULTS: PP prolonged the lag phase and the half-time of emptying of the solid meal. The change in hunger rating, satiety, desire to eat after the meal, or prospective consumption was not affected. The postprandial rise in plasma glucose was prolonged by PP. The postprandial rise in insulin was also delayed by PP. PP had no significant effect on the emptying of water. CONCLUSIONS: PP inhibits gastric emptying of solid food and delays the postprandial rise in plasma glucose and insulin. PP is suggested to have a physiological role in the pancreatic postprandial counterregulation of gastric emptying and insulin secretion.

Inhibitory effect of exogenous orexin a on gastric emptying, plasma leptin, and the distribution of orexin and orexin receptors in the gut and pancreas in man.

Orexin A (OXA) is a novel peptide that appears to play a role in the regulation of food intake, arousal, and energy balance. The aim of this study was to study the effect of iv infusion of OXA on gastric emptying, appetite, leptin, ghrelin, and glucose metabolism in man (six normal men) and the localization of OXA and orexin receptors (OXRs) 1 and 2 in the human gut. Gastric emptying was studied scintigraphically after ingestion of a 99mTc-labeled omelet and iv infusion of OXA (10 pmol/kg.min). Appetite ratings and blood samples were obtained at regular intervals. The immunohistochemical distribution of OXA and OXRs was examined using antibodies recognizing OXA, OX1R, and OX2R in human gastrointestinal tissue. OXA had no effect on lag phase or gastric half-emptying time. However, the gastric emptying rate was significantly slower without affecting appetite ratings. Plasma concentrations of insulin were increased by OXA, whereas plasma leptin decreased and ghrelin was unchanged. OXA immunoreactivity was observed in a subset of neurons and varicose nerve fibers in the mucosa, ganglia, and circular muscle layer and mucosal endocrine cells in the stomach and small intestine. OXA-immunoreactive cells in the islets of Langerhans contained insulin with a subset expressing OX2R. In conclusion, peripheral OXA seems to slightly affect the regulation of gastric emptying in humans without affecting appetite ratings. OXA decreased plasma levels of leptin, suggesting a possible interaction between leptin and OXA in the regulation of energy homeostasis.

Bone mineral density among premenopausal women with early breast cancer in a randomized trial of adjuvant endocrine therapy.

PURPOSE: To examine the effects on bone mineral density of 2 years of treatment with a luteinizing hormone-releasing hormone (LHRH) agonist alone or in combination with tamoxifen or tamoxifen alone in premenopausal breast cancer. PATIENTS AND METHODS: We recruited 89 women from two centers in Stockholm participating in a randomized multicenter trial of three different endocrine approaches in the adjuvant setting (Zoladex in Premenopausal Patients Trial). The women were assigned to receive the LHRH agonist goserelin with or without tamoxifen, tamoxifen alone, or no endocrine therapy. The treatment was given for 2 years. We measured total-body bone density before start of treatment and at 12, 24, and 36 months. RESULTS: After 2 years of treatment, there was a significant loss of bone mineral density (mean change, -5%; P <.001) in the women receiving goserelin alone. The combined goserelin and tamoxifen treatment, as well as tamoxifen alone, resulted in a lesser but statistically significant decline in bone mineral density (mean change, -1.4%; P =.02; and -1.5%; P <.001). One year after cessation of treatment, the goserelin group alone showed a partial recovery from bone loss (mean change, 1.5%; P =.02). CONCLUSION: Two years of ovarian ablation from goserelin treatment caused a significant reduction in bone mineral density but there was a partial recovery from the bone loss 1 year after cessation of treatment. The addition of tamoxifen seems to partially counteract the demineralizing effects of goserelin.

Reduced food intake after jejunoileal bypass: a possible association with prolonged gastric emptying and altered gut hormone patterns.

The object of this study was to examine whether eating behavior, food preference, gastric emptying, and gut hormone patterns are altered after jejunoileal bypass (JIB) in patients with severe obesity. Eight obese [mean (+/- SD) body mass index (BMI; in kg/m2) 42.9 +/- 4] subjects were studied prospectively before and 9 mo after JIB with eight age- and sex-matched normal-weight control subjects. Total energy intake, data from the universal eating monitor (VIKTOR), eating motivation measured by visual analog scales, a food-preference checklist, a forced-choice list, solid-phase gastric emptying, and postprandial concentrations of cholecystokinin, motilin, and neurotensin were studied. BMI was reduced by 29% after JIB. Compared with normal subjects, the JIB patients showed a reduced desire to eat, decreased hunger, and reduced prospective consumption before a test meal. After surgery, obese subjects selected fewer food items and showed a reduced preference for high-carbohydrate and high-fat items before a test meal. There was a trend from an accelerated toward a decelerated eating pattern in obese subjects after JIB. After JIB, gastric emptying of obese subjects was slowed and similar to that in control subjects. Obese subjects had lower postprandial cholecystokinin concentrations that were lower than those of control subjects both before and after JIB. Postprandial concentrations of neurotensin were higher after JIB. We conclude that after JIB, the desire to eat and preference for high-carbohydrate and high-fat items is reduced, resulting in decreased energy intake. That gastric emptying is prolonged and gut hormone patterns are altered with low postprandial plasma cholecystokinin and high neurotensin plasma concentrations may at least partly account for these observations.

Somatostatin in neuroblastoma and ganglioneuroma.

Neuroblastoma, a childhood tumour of the sympathetic nervous system, may in some cases differentiate to a benign ganglioneuroma or regress due to apoptosis. Somatostatin may inhibit neuroblastoma growth and induce apoptosis in vitro and was therefore investigated. Using a radioimmunoassay, we found that all ganglioneuromas contained high somatostatin concentrations (> 16 pmol/g), significantly higher than neuroblastomas (n = 117, median 2.8 pmol/g), healthy adrenals, Wilms' tumours, phaeochromocytomas and other neuroendocrine tumours (P < 0.001). Neuroblastomas contained more somatostatin than control tumours (P < 0.001-0.05). Neuroblastomas amplified for the MYCN oncogene contained less somatostatin than non-amplified tumours (1.2 pmol/g versus 4.0 pmol/g, respectively; P = 0.026). In a clinically unfavourable neuroblastoma subset (age > 12 months, stage 3 or 4) 16 children with high concentrations of somatostatin in primary tumours had a better prognosis than 23 with low somatostatin (46.7% versus 0% survival at 5 years, P < 0.005). Scintigraphy using 111In-pentetreotide identified tumours expressing high-affinity somatostatin receptors in vivo. However, no significant correlation was found between somatostatin receptor expression and peptide content in 15 tumours. Similarly, human SH-SY5Y neuroblastoma xenografts grown in nude rats showed low somatostatin concentrations, but were positive for somatostatin receptor scintigraphy. Treatment of these rats with the somatostatin analogue octreotide seemed to upregulate in vivo receptor expression of somatostatin and vasoactive intestinal peptide more effectively than 13-cis retinoic acid. In conclusion, somatostatin in neuroblastoma is associated with differentiation to benign ganglioneuromas in vivo and favourable outcome in advanced tumours. Furthermore, somatostatin receptor scintigraphy may identify tumours with high-affinity receptors in children that might benefit from targeted therapy using synthetic somatostatin analogues.

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.

Collimator design for improved spatial resolution in SPECT and planar scintigraphy.

UNLABELLED: This paper evaluates the design of a new planar-concave collimator with nonuniform response that better matches the body shape than conventional collimators. METHODS: The collimator properties are evaluated and assessed by means of both a stimulation program and an experimental test using a prototype planar-concave collimator. RESULTS: The results, for points located 150 mm from the axis of rotation, demonstrate that the ratio of radial and tangential spatial resolution in SPECT with the new collimator decreased by 40%, as compared to SPECT with a standard collimator. In planar scintigraphy, the spatial resolution improved correspondingly from 10.9 mm (FWHM) to 7.8 mm in lateral areas of the body. CONCLUSION: The new collimator reduces nonisotropic blurring in SPECT in addition to improving spatial resolution in both planar scintigraphy and in SPECT.

Comparison of technetium-99m-MIBI and technetium-99m-tetrofosmin uptake by musculoskeletal sarcomas.

UNLABELLED: Technetium-99m-MIBI was initially developed for heart studies but it can also be used to depict tumors, predict multidrug resistance and evaluate chemotherapy. Recently, 99mTc-tetrofosmin, which exhibits similar physical properties, has been launched for heart studies. Tumor uptake and prediction of multidrug resistance have also been reported regarding the latter tracer. A comparison of these two tracers regarding the detectability of musculoskeletal sarcoma has been made. METHODS: Twenty patients with musculoskeletal sarcoma of the extremities or pelvis underwent planar examination after the administration of 99mTc-MIBI and 99mTc-tetrofosmin with an interval of 2-7 days. The tumor activity was compared with one ipsilateral and one contralateral background region. RESULTS: There was a small, but not significant, difference in favor of 99mTc-MIBI with regard to both background regions. CONCLUSION: Technetium-99m-MIBI and 99mTc-tetrofosmin can both be used to visualize musculoskeletal sarcomas. The choice may depend on which agent is used routinely for myocardial studies in the laboratory.

A new method for granulocyte labeling with technetium-99m: preliminary results in abscess detection.

A new method for 99mTc-labeling of granulocytes for clinical routine use has been developed. The labeling is simple to perform by means of a kit of radiopharmaceutical quality, utilizing dihydroxy-benzoic acid. Pretinning techniques are avoided. The technique has been applied clinically in 15 patients with indications of intra-abdominal abscess. In six patients, [99mTc]granulocyte scintigraphy at 3 hr and/or 24 hr after i.v. administration, correctly depicted the abscess, as verified by subsequent surgery. In the remaining patients, who were negative at surgery or recovered without operation, all scans were negative.

Pulmonary perfusion is more uniform in the prone than in the supine position: scintigraphy in healthy humans.

The main purpose of this study was to find out whether the dominant dorsal lung perfusion while supine changes to a dominant ventral lung perfusion while prone. Regional distribution of pulmonary blood flow was determined in 10 healthy volunteers. The subjects were studied in both prone and supine positions with and without lung distension caused by 10 cmH2O of continuous positive airway pressure (CPAP). Radiolabeled macroaggregates of albumin, rapidly trapped by pulmonary capillaries in proportion to blood flow, were injected intravenously. Tomographic gamma camera examinations (single-photon-emission computed tomography) were performed after injections in the different positions. All data acquisitions were made with the subject in the supine position. CPAP enhanced perfusion differences along the gravitational axis, which was more pronounced in the supine than prone position. Diaphragmatic sections of the lung had a more uniform pulmonary blood flow distribution in the prone than supine position during both normal and CPAP breathing. It was concluded that the dominant dorsal lung perfusion observed when the subjects were supine was not changed into a dominant ventral lung perfusion when the subjects were prone. Lung perfusion was more uniformly distributed in the prone compared with in the supine position, a difference that was more marked during total lung distension (CPAP) than during normal breathing.