The role of scintigraphy in the evaluation of brain malignancies.

The gold standard for diagnosis of primary brain tumors is histopathological evaluation of the obtained tissue samples. Nevertheless, anatomical and functional imaging modalities have a determinative role in the precise localization and characterization of these lesions. In this review we focus on the clinical applications and future potentials of nuclear medicine procedures. Several single photon emission tomography (SPET) tracers such as thallium-201 chloride ((201)TlCl(2)), technetium-99m ((99m)Tc) methoxyisobutylisonitrile (MIBI), (99m)Tc-tetrofosmin (TF) and 3-[iodine-123] iodo-α- methyl-L-tyrosine ((123)I-IMT) have been utilized in the diagnosis of brain tumors. Positron emission tomography (PET) alone or fused with computed tomography (CT), are widely acceptable methods in oncology, at present and for the future.

Role of scintigraphy in inflammatory bowel disease.

The diagnosis of inflammatory bowel disease (IBD) depends on direct endoscopic visualization of the colonic and ileal mucosa and the histological study of the obtained samples. Radiological and scintigraphic methods are mainly used as an adjunct to endoscopy. In this review, we focus on the diagnostic potential of nuclear medicine procedures. The value of all radiotracers is described with special reference to those with greater experience and more satisfactory results. Tc-99m hexamethylpropylene amine oxime white blood cells remain a widely acceptable scintigraphic method for the diagnosis of IBD, as well as for the evaluation of disease extension and severity. Recently, pentavalent Tc-99m dimercaptosuccinic acid has been recommended as an accurate variant and a complementary technique to endoscopy for the follow-up and assessment of disease activity. Positron emission tomography alone or with computed tomography using fluorine-18 fluorodeoxyglucose appears to be a promising method of measuring inflammation in IBD patients.

Is there a role for Tc-99m (V) DMSA scintigraphy in ischemic colitis?

AIM: To evaluate the role of pentavalent Tc-99m dimercaptosuccinic acid [Tc-99m (V) DMSA] in the diagnosis of ischemic colitis. METHODS: Fourteen patients with endoscopically and histologically confirmed ischemic colitis were included in the study. Tc-99m (V) DMSA scintigraphy was performed within 2 d after colonoscopy. Images were considered positive when an area of increased activity was observed in the region of interest and negative when no abnormal tracer uptake was detected. RESULTS: In 3 out of the 14 patients, Tc-99m (V) DMSA images showed moderate activity in the bowel. The scintigraphic results corresponded with the endoscopic findings. In the other 11 patients, no abnormal tracer uptake was detected in the abdomen. CONCLUSION: Besides the limited number of patients, Tc-99m (V) DMSA could not be considered as a useful imaging modality for the evaluation of ischemic colitis.

Active inflammatory bowel disease: head-to-head comparison between 99mTc-hexamethylpropylene amine oxime white blood cells and 99mTc(V)-dimercaptosuccinic acid scintigraphy.

PURPOSE: Evaluation and comparison between pentavalent 99mTc dimercaptosuccinic acid (99mTc(V)-DMSA) and 99mTc-hexamethylpropylene amine oxime white blood cell (99mTc-HMPAO WBC) scintigraphy in the detection and assessment of disease activity in patients with active inflammatory bowel disease (IBD). MATERIALS AND METHODS: 99mTc(V)-DMSA scintigraphy was performed in 23 patients with active IBD and true positive 99mTc-HMPAO WBC scintigraphy. Images were considered positive when an area of increased uptake was observed. To assess severity of IBD, semi-quantitative analysis was included with reference to the uptake in the iliac crest. Comparison with endoscopic, radiological and clinical data was performed. RESULTS: The diagnostic accuracy of 99mTc-HMPAO WBC and 99mTc(V)-DMSA was 91% and 84%, respectively. A significant correlation between the findings of both radioisotopic methods and scintigraphy score was demonstrated. Endoscopic findings were significantly correlated with scintigraphic results. Kappa statistics showed a moderate to good agreement between the two scintigraphic methods. Two patients (8.8%) had negative findings with 99mTc(V)-DMSA scintigraphy (false negative results). CONCLUSION: 99mTc(V)-DMSA compared to 99mTc-HMPAO WBC could provide a simple, non-invasive alternative method for the assessment of disease activity, although it is slightly inferior to 99mTc-HMPAO WBC scintigraphy especially in the evaluation of disease localization in IBD patients.

[Nuclear Medicine in the diagnosis of lower gastrointestinal bleeding].

Lower gastrointestinal bleeding appears to be a frequent problem in the every day practice. The exact localisation of the bleeding site plays a major role in treatment planning. Nuclear Medicine imaging techniques allow the diagnosis of ectopic gastric mucosa-Meckel's diverticulum (MD) and the extravasation of red blood cells. Meckel's diverticulum is the most frequent congenital anomaly of the gastrointestinal system moreover bleeding seems to be the most important clinical symptom during childhood. Scintigraphy using technetium-99m pertechnetate ((99m)TcO(4)(-)) is the method of choice for the diagnosis of ectopic gastric mucosa in MD. The use of this test in children is of high diagnostic accuracy, with a sensitivity of 85%-95% and specificity of 90%-95%. In adults, lower gastrointestinal bleeding is commonly caused by tumors, colitis, dysplasias or polyps, while MD is rare. Scintigraphic demonstration of active lower gastrointestinal bleeding contributes to risk-stratification, to prognosis, appropriate timing for angiography and to planning of surgical intervention. (99m)Tc labelled erythrocytes and (99m)Tc sulphur colloid are commonly used radiopharmaceuticals each having its own indications and used for the diagnosis of active bleeding. Moreover delayed imaging is possible using (99m)Tc labelled erythrocytes, enabling the diagnosis of intermittent bleeding. Careful interpretation of the scintiscan images is essential to avoid numerous pitfalls. The indications for using the specific nuclear medicine technique as above, for the diagnosis of lower gastroinstestinal bleeding and the indications for using other methods besides those of nuclear medicine are described.

Urine interleukin-8 as a marker of vesicoureteral reflux in infants.

OBJECTIVE: Vesicoureteral reflux (VUR) is a common finding in children presenting with urinary tract infection (UTI) and prenatally diagnosed urinary tract dilatation and in relatives of index patients. Children with VUR are at risk for ongoing renal damage with subsequent infections. Detecting VUR and renal scarring currently depends on imaging modalities with associated problems of radiation, invasiveness, and expense. Noninvasive methods would greatly facilitate diagnosis and would also help in identifying relatives of index cases who should be screened. Interleukin-8 (IL-8) is produced by epithelial cells of the renal tract in response to inflammatory stimuli and has been shown to increase during acute UTI. The objective of this study was to assess the urine levels of IL-8 as a noninvasive marker of VUR in infants in the absence of a recent UTI episode. METHODS: We evaluated urine concentrations of IL-8 in 59 infants aged 1 month to 2 years. All infants were free of UTI for a minimum of 3 weeks before IL-8 evaluation. Infants were divided into 3 groups: group A, subjects with proven VUR (24 infants aged 0.15-1.95 years, median 0.43); group B, subjects with a history of UTI but negative investigation for VUR (14 infants aged 0.32-1.95 years, median 0.57); and group C, subjects without any history of acute or chronic condition that might impair renal function (21 infants aged 0.08-1.92 years, median 0.33). IL-8 concentrations were determined by a commercially available quantitative enzyme-linked immunosorbent assay. To avoid dilution effects, urinary levels of IL-8 were expressed as the ratio of cytokine-to-urinary creatinine. RESULTS: Results were presented as medians and ranges. The Kruskal-Wallis test, the Mann-Whitney rank sum U test, and the Spearman rank order correlation test were performed for the univariate analysis. Two-tailed P values were calculated and the conventional level of significance P < .05 was applied in all cases. Infants in groups A and B had been free of UTI for a period of 3 to 52 weeks (median, 5.0 weeks) and 3 to 78 weeks (median, 4.5 weeks), respectively, before IL-8 determination. No significant difference was noted in the length of the UTI-free period between groups A and B (P = .469). Urine creatinine concentrations did not differ among groups A, B, and C (medians 1.15, 2.25, and 1.15 micromol/mL, respectively; P = .080). The median urine IL-8/creatinine concentrations (pg/micromol) were 40.5 (range, 2.04-3874) in group A, 1.91 (range, 0.001-386) in group B, and 2.47 (range, 0.002-55.6) in group C. Urine IL-8/creatinine concentrations were significantly higher in group A than both in group B (P = .0003) and in group C (P < .0001). No significant difference was observed between groups B and C (P = .749). In group A, no significant correlation was shown between IL-8/creatinine concentrations and the presence of renal parenchymal damage (P = .506), reflux grade (P = .770), or time from UTI (P = .155). A receiver-operator characteristic curve was constructed by plotting the sensitivity versus the specificity for different cutoff concentrations of IL-8/creatinine. With a cutoff concentration of urinary IL-8/creatinine at 5 pg/micromol, the sensitivity of this marker in diagnosing VUR was 88%, the specificity 69%, the positive prognostic value 66%, and the negative prognostic value 89%. In higher cutoff concentrations, specificity of the marker increased but sensitivity rapidly decreased. CONCLUSIONS: We present evidence that urine IL-8 concentrations remain elevated in infants with VUR even in the absence of UTI and that a cutoff of 5 pg/micromol IL-8/creatinine is of high sensitivity and adequate specificity for diagnosing VUR. Elevated urine IL-8 levels in VUR and renal scarring have already been reported; however, the present study is, to our knowledge, the first to confirm significant differences between infants with VUR and infants with a history of UTI alone and healthy controls, and to suggest a reliable cutoff concentration for diagnosing VUR. Our findings additionally suggest that inflammatory process in VUR is ongoing even after UTI has resolved, pointing against the currently held belief that sterile reflux cannot harm kidneys. The chronic inflammatory cell infiltrate associated with reflux nephropathy rather than VUR itself might offer an explanation for the secretion of IL-8, which may well be independent of reflux grade. Using urine IL-8 for diagnosing VUR is not free of limitations, because IL-8 may be elevated as a result of urinary tract manipulation or undetected UTI. In addition, this study focused on infants and not in older children with longstanding VUR. Increased urine IL-8 concentrations after UTI has resolved is a promising noninvasive marker for an initial screening for VUR in infancy with high sensitivity and adequate specificity.

Active inflammatory bowel disease: evaluation with 99mTc (V) DMSA scintigraphy.

PURPOSE: To evaluate the use of pentavalent (V) technetium 99m (99mTc) dimercaptosuccinic acid (DMSA) scintigraphy for the assessment of disease activity in patients with inflammatory bowel disease (IBD). MATERIALS AND METHODS: 99mTc (V) DMSA scintigraphy was performed in 76 patients. There were 36 patients with active IBD (11 with ulcerative colitis, 25 with Crohn disease), 28 patients with inactive disease (eight with ulcerative colitis, 20 with Crohn disease), and 12 patients with miscellaneous bowel disease. Sensitivity and specificity of 99mTc (V) DMSA scintigraphy in the diagnosis of IBD were calculated. In the group with active IBD, the disease activity and laboratory indices, as well as the endoscopic and histologic activity, were compared with the scanning activity index. Correlation coefficients between them were calculated with the Spearman rank test. RESULTS: 99mTc (V) DMSA scintigraphy had a 92% (33 of 36) sensitivity and an 86% (24 of 28) specificity in the detection of active IBD. A significant correlation between disease activity indices and scintigraphy score was demonstrated. Endoscopic and histologic activity was significantly correlated (P =.005 and.02, respectively, overall disease activity) with the scanning activity score. Of the group of patients with miscellaneous bowel disease, three with ischemic colitis had negative findings at scintigraphy. CONCLUSION: 99mTc (V) DMSA scintigraphy provides a noninvasive, practical, and accurate assessment of IBD activity.

Myocardial perfusion and adrenergic innervation in patients with RBBB and LAfB: the effect of altering the activation sequence with right ventricular apical pacing.

The aim of this study was to investigate myocardial perfusion and adrenergic innervation in patients with intraventricular conduction disturbances and to detect any changes caused by alteration of the ventricular activation sequence as a result of right ventricular apical pacing. We studied 15 patients with right bundle branch block (RBBB) and left anterior fascicular block (LAFB), while 15 healthy individuals served as controls. All patients underwent planar and single-photon emission computed tomography (SPECT) myocardial imaging after intravenous infusion of 5mCi 123I-metaiodobenzylguanidine (123I-MIBG) and a SPECT thallium201 myocardial perfusion study before and 3 months after pacemaker implantation. The heart to mediastinum ratio was calculated during the 123I-MIBG study in order to assess the global cardiac sympathetic activity and was significantly smaller in patients than in controls (P < 0.001). Patients with RBBB and LAFB revealed regional adrenergic innervation defects, mostly in the inferior and posterior walls. After a medium-term pacing period, a redistribution of 123I-MIBG uptake was detected, with aggravation of adrenergic innervation defects in the apical and posterior walls and amelioration in septal and anterior walls. Five patients showed perfusion defects that remained unchanged after pacing. Two others displayed mild myocardial perfusion defects that did not exist before pacing. In conclusion, patients with RBBB and LAFB reveal global and regional disturbances of myocardial adrenergic innervation, which shows redistribution as a result of the altered propagation of the ventricular electrical activation. To a smaller degree these patients reveal myocardial perfusion disturbances in which pacing has a limited medium-term effect.