Jordi Fuertes

DMSA study performed during febrile urinary tract infection: a predictor of patient outcome?

Technetium-99m dimercaptosuccinic acid (DMSA) study has been advocated as a method for the assessment of renal sequelae after acute febrile urinary tract infection (UTI). However, it is not known whether DMSA scintigraphy performed during acute UTI has any prognostic value for outcome assessment. The objective of this study was to evaluate the usefulness of DMSA scintigraphy performed during UTI as a predictor of patient outcome, to identify children at risk of events [vesico-ureteral reflux (VUR) or recurrent UTI] that may lead to the development of progressive renal damage. One hundred and fifty-two children (including 78 girls) with a mean age of 20 months (range 1 month to 12 years) with first febrile UTI were evaluated by DMSA scintigraphy during acute UTI. After acute UTI, children were explored by voiding cysto-urethrography. Children who presented an abnormal DMSA study, or a normal DMSA study but VUR or recurrent UTI, underwent a DMSA control study 6 months after UTI. Children with VUR were followed up by direct radionuclide cystography. DMSA scintigraphy performed during acute UTI was normal in 112 children (74%). In 95 of these children, follow-up DMSA scintigraphy was not performed owing to a good clinical outcome. In the remaining 17 children, follow-up scintigraphy was normal. Forty children (26%) presented abnormal DMSA study during acute UTI. Twenty-five of them presented a normal follow-up DMSA, and 15 presented cortical lesions. Children with abnormal DMSA had a higher frequency of VUR than children with normal DMSA (48% vs 12%). It is concluded that children with normal DMSA during acute UTI have a low risk of renal damage. Children with normal follow-up DMSA and low-grade VUR have more frequent spontaneous resolution of VUR.

Demencia con cuerpos de Lewy y enfermedad de Alzheimer: diagnóstico diferencial mediante estudio de la inervación simpática cardíaca con MIBG

Resumen La demencia con cuerpos de Lewy (DCL) es la segunda causa de demencia degenerativa despues de la enfermedad de Alzheimer (EA), basandose su diagnostico en Criterios Clinicos de Consenso Internacional y siendo el diagnostico de certeza post-mortem . El diagnostico diferencial entre ambas enfermedades permite facilitar el manejo terapeutico de los pacientes con DCL, que presentan una sensibilidad especial a los neurolepticos y un tratamiento dificil de sus sintomas psicoticos. Objetivo Valorar la utilidad del estudio cardiaco con MIBG en el diagnostico diferencial entre DCL y EA. Material y metodos Se realizo gammagrafia cardiaca con MIBG a 16 pacientes con criterios clinicos de probable DCL (7 hombres, edad media 77 anos [rango 62-89 anos], MMSE medio 17 [rango 11-28]) y a 9 pacientes con criterios clinicos de probable EA (3 hombres, edad media 79 anos [rango 61-87 anos], MMSE medio 17 [rango 4-25]). Se obtuvo imagen planar anterior de torax a los 15 minutos (estudio precoz) y 4 horas (estudio tardio) post-administracion del trazador. Se cuantifico la captacion cardiaca de MIBG mediante el indice corazon/mediastino (ICM). Se considero normal un ICM > 1,8. Resultados La DCL mostro un ICM disminuido respecto a la EA, tanto en el estudio precoz (1,34 ± 0,27 [rango 1,03-1,98] respecto a 1,84 ± 0,22 [rango 1,53-2,15], p Conclusiones El estudio cardiaco con MIBG puede ser un instrumento util para establecer el diagnostico diferencial entre DCL y EA.

99mTc-depreotide scintigraphy of bone lesions in patients with lung cancer

PurposeScintigraphy with 99mTc-depreotide, a somatostatin analogue–technetium ligand, has been used for evaluation of various malignant neoplasms, including lung cancer. The diagnosis of bone metastases in patients with lung cancer is not always definitive with current imaging methods. Visualisation of somatostatin receptors (SSTRs) in bone lesions, when the primary tumour exhibits such receptors, could be helpful in characterising them as metastatic. The aim of this study was to assess the value of 99mTc-depreotide in differentiating between benign and malignant bone lesions in patients with lung cancer.MethodsThe study population comprised 20 patients (17 males and three females, mean age 63 years) with proven lung cancer in whom bone lesions had been detected by conventional imaging methods. All patients underwent 99mTc-hydroxydiethylene diphosphonate and 99mTc-depreotide scintigraphy within 2 weeks. Bone lesions were classified as benign or malignant on the basis of clinical, imaging and/or histological criteria.Results99mTc-depreotide uptake in the primary tumour was seen in 19 of the 20 patients. Conventional imaging methods detected 55 bone lesions, 31 of which were classified as malignant. Twenty-eight (90%) of these lesions showed 99mTc-depreotide uptake, suggesting bone metastases, while three did not. Twenty-four bone lesions were classified as benign by conventional imaging methods, and none of them showed 99mTc-depreotide uptake. In addition, 99mTc-depreotide demonstrated extra-osseous lesions in six patients.Conclusion In patients with lung cancer and bone lesions, 99mTc-depreotide scintigraphy uptake in the bone lesions supports the diagnosis of malignancy, in particular if the primary lung tumour also exhibits SSTRs. Furthermore, whole-body 99mTc-depreotide scintigraphy may disclose extra-osseous disease.

Incidental focal uptake in colorectal location on oncologic FDG PET and PET/CT studies: Histopathological findings and clinical significances

PURPOSE Unexpected focal colonic or rectal radiotracer activity is an usual finding in patients subjected to a PET study. The aim of this work has been to evaluate the clinical significance of this finding in the prediction of an existing colorectal malignancy. MATERIAL AND METHODS During the last three years, all patients studied with (18)F-FDG PET/CT and PET for oncologic work-up purposes were prospectively surveyed for focal colorectal radiotracer activity. Colonoscopy was performed in all patients with this incidental finding in order to exclude colonic malignancy. CEA level, maximum standardized uptake value (SUVmax), CT findings, colonoscopy findings and histopathological results were prospectively analyzed in all patients. RESULTS A total of 2290 patients were evaluated, 158 of whom were studied with PET and the remainder with a hybrid PET/CT. Focal FDG colorectal activity was incidentally detected in 27 patients with no previous history of colorectal cancer. Colorectal adenocarcinoma was diagnosed in seven (25.9%) patients. A pre-cancerous lesion was found in eleven patients (40.7%). Eight patients (29.6%) had no macroscopic lesions. One patient was diagnosed with a benign lesion. Any focal activity found in the colon by (18)F-FDG PET/CT examination predicts a probability greater than 50% of an underlying malignant or premalignant lesion in the histopathological analysis (logistic regression, p=0.01), independently of the calculated SUVmax. CONCLUSION According to the results of the present study, we recommend the performance of a colonoscopy and biopsy of any suspicious lesions, in all patients with unexpected focal FDG activity found in colon or rectum during a (18)F-FDG PET/CT examination.

Functional neuroimaging in Hashimoto’s encephalitis: a physiopathological imaging?

Tc-ECD brain perfusion single photonemission computed tomography (SPECT) scan, whichshowed global and severe hypoperfusion of the whole braincortex (upper row). Anatomical neuroimaging (CT, MRI)was near-normal, showing only mild age-related corticalatrophy. After 8 months of corticoid therapy, the patientexperienced a progressive clinical recovery of superiorfunctions, and a control SPECT scan showed normal brainperfusion (lower row). The hypoperfusion pattern found inthis patient might have been related to a vasculitic mechanismas has been reported in this kind of encephalopathy [2, 3].References

Visualisation of sodium-iodide symporter.

A 60-year-old man with an 11-year history of mucinous adenocarcinoma of the salivary gland and a 4-year history of pulmonary metastases underwent pertechnetate (TcO4 ) scintigraphy of the thyroid gland. As abnormal pulmonary TcO4 − uptake was observed, whole-body (a) and thoracic SPECT-CT (b) studies were performed, which showed images of focal pulmonary tracer uptake matching radiological images of pulmonary metastases. At the time of these studies, tumour marker levels were: CA 19-9, 2,761 kU/l; CA-125, 1,170 kU/l; CA 15-3, 172 kU/l. The sodium-iodide symporter (NIS) is an integral plasma membrane glycoprotein involved in the active transport of iodide into the thyroid follicular cells [1, 2]. In addition to the thyroid gland, NIS is expressed in non-thyroid tissues, including salivary glands, stomach, thymus and breast [2, 3]. Recently, NIS has been proposed as a target for non-thyroid malignancies that express the symporter [4, 5]. Since the transport of pertechnetate, like that of iodide, is NISmediated, pertechnetate could have a role in the assessment of tumours derived from organs expressing NIS and their metastases.