Particular imaging features and customized thermal ablation treatment for intramedullary osteoid osteoma in pediatric patients.

OBJECTIVE: To report on the particular imaging features and high success rate of cold mode radio-frequency thermal ablation (RFTA) as the treatment of choice for intramedullary osteoid osteoma. MATERIALS AND METHODS: The study population consisted of 51 patients (39 males, 12 females; mean age 7.2 years; 11 patients under 6 years of age, including 7 males and 4 females) who underwent RFTA for osteoid osteoma and were retrospectively observed. The affected sites were the tibia (n = 22, 43%), femur (n = 13, 25%), pelvis (n = 5, 10%), anklebone (n = 3, 6%), humerus (n = 2, 4%), sacrum (n = 2, 4%), heel, radium, patella ,and rib (n = 1, 2%), respectively. Three patients had tibial intramedullary osteoid osteoma (14% of the tibial lesions, 6% of all cases). Cold mode RFTA was performed for these three patients to obtain a large ablation area without positioning two probes. The noncooled mode was used to treat cortical and subperiosteal lesions. RESULTS: Following RFTA, all patients were pain-free and in good clinical condition. In the intramedullary osteoid osteoma group, no recurrences were observed during the 24-month follow-up period, but one patient, who was affected by cortical osteoid osteoma, required two RFTA treatments to heal completely. CONCLUSION: Children less than 6 years of age with recurrent nocturnal pain and limb swelling should be investigated for intramedullary osteoid osteoma. Once confirmed, CT-guided RFTA should be the first treatment for intramedullary osteoid osteomas because of the high success rate and reduced invasivity, especially with cold mode RFTA. The outcome is related to the disappearance of pain, and the efficacy may be checked shortly after treatment with MR imaging to evaluate the absence of lesion in the ablation area.

Experimental determination of the radionuclide calibrator setting for Technesium-99m, by using a primary standardisation method.

BACKGROUND: A new 99mTc national standard has been developed at the Italian National Metrology Institute for Ionizing Radiation quantities of ENEA (ENEA-INMRI). METHODS: The stock radioactive solution was prepared at the Ospedale Pediatrico Bambino Gesù (OPBG) and standardized at the ENEA-INMRI by using the 4pigamma absolute measurement method. The new standard was used to calibrate the dose calibrator of the OPBG Nuclear Medicine Unit (NMU) and the ENEA-INMRI portable ionization chamber which was employed as the secondary standard measurement system to calibrate the dose calibrator of another Italian nuclear medicine unit. RESULTS AND CONCLUSION: Remarkable improvement of measurement accuracy was achieved. The importance of traceable calibrations is underlined. Specific comments are made about quality control performance and measurement accuracy for the instrumentation used in nuclear medicine units of paediatric hospitals.

Delayed gastric emptying and typical scintigraphic gastric curves in children with gastroesophageal reflux disease: could pyloromyotomy improve this condition?

BACKGROUND/PURPOSES: Delayed gastric emptying (DGE) is a cofactor in the etiopathogenesis of gastroesophageal reflux disease (GERD). Scintigraphy is the criterion standard to evaluate gastric emptying (GE). This study aims to define typical scintigraphic activity-time curves (ATCs) related to DGE and esophageal atresia (EA) and to demonstrate the effectiveness of pyloromyotomy (P) in improving GE. METHODS: Since 2002, 83 children underwent Nissen fundoplication. Patients were divided into 2 groups: group I, GERD-only patients; group II, patients with GERD owing to EA. Depending on preoperative scintigraphy, each group was subdivided into 2 subgroups. Before surgery and 1 year after, endoscopy and scintigraphy were performed. In the presence of DGE, P was associated with Nissen fundoplication. Gastric emptying differences at baseline and at follow-up were estimated by the Student t test. Pre- and post-ATCs were evaluated by the χ(2) test. RESULTS: During follow-up, GE completely normalized in subgroups with DGE. Scintigraphic ATC analysis documented an association between DGE and a typical rectilinear fitting, with a higher rate in EA patients. After P, the scintigraphic pattern changed in an exponential manner related to a faster GE. CONCLUSIONS: Delayed gastric emptying is frequent in EA, and the scintigraphic ATCs are typical. Pyloromyotomy is a safe and effective technique to fully normalize GE.

Rhabdomyosarcoma associated hypertrophic osteoarthropathy in a child: detection by bone scintigraphy.

Hypertrophic osteoarthropathy (HOA) is characterized by digital clubbing, long bone periosteal reaction, and polyarthralgias. Primary familial HOA is very rare and is not associated with underlying disorders and has a good prognosis. Secondary pediatric nonneoplastic HOA is associated with cystic fibrosis, congenital heart disease, biliary atresia, and inflammatory bowel disease. Secondary neoplastic HOA may be associated with intra or extrathoracic tumors.A 5-year-old girl was admitted to our hospital for an abdominal mass, digital clubbing, and diffuse articular pain. The bone scan revealed symmetrical tracer uptake in the long bones. Upper and lower extremity x-rays were diagnostic for HOA. Paraneoplastic HOA in childhood accounts for not more than 12% of HOA paitents. HOA has been reported in 2 other cases of rhabdomyosarcoma.

Guidelines for lung scintigraphy in children.

The purpose of this set of guidelines is to help the nuclear medicine practitioner perform a good quality lung isotope scan. The indications for the test are summarised. The different radiopharmaceuticals used for the ventilation and the perfusion studies, the technique for their administration, the dosimetry, the acquisition of the images, the processing and the display of the images are discussed in detail. The issue of whether a perfusion-only lung scan is sufficient or whether a full ventilation-perfusion study is necessary is also addressed. The document contains a comprehensive list of references and some web site addresses which may be of further assistance.