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Abstract Background 18F-fluoro-deoxy-glucose (18 F-FDG) positron emission tomography integrated/combined with computed tomography (PET-CT) provides the best diagnostic results in the metabolic characterization of undetermined solid pulmonary nodules. The diagnostic performance of 18 F-FDG is similar for nodules measuring at least 1 cm and for larger masses, but few data exist for nodules smaller than 1 cm. Case presentation We report five cases of oncologic patients showing focal lung 18 F-FDG uptake on PET-CT in nodules smaller than 1 cm. We also discuss the most common causes of 18 F-FDG false-positive and false-negative results in the pulmonary parenchyma. In patient 1, contrast-enhanced CT performed 10 days before PET-CT did not show any abnormality in the site of uptake; in patient 2, high-resolution CT performed 1 month after PET showed a bronchiole filled with dense material interpreted as a mucoid impaction; in patient 3, contrast-enhanced CT performed 15 days before PET-CT did not identify any nodules; in patients 4 and 5, contrast-enhanced CT revealed a nodule smaller than 1 cm which could not be characterized. The 18 F-FDG uptake at follow-up confirmed the malignant nature of pulmonary nodules smaller than 1 cm which were undetectable, misinterpreted, not recognized or undetermined at contrast-enhanced CT. Conclusion In all five oncologic patients, 18 F-FDG was able to metabolically characterize as malignant those nodules smaller than 1 cm, underlining that: 18 F-FDG uptake is not only a function of tumor size but it is strongly related to the tumor biology; functional alterations may precede morphologic abnormalities. In the oncologic population, especially in higher-risk patients, PET can be performed even when the nodules are smaller than 1 cm, because it might give an earlier characterization and, sometimes, could guide in the identification of alterations missed on CT.

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Background: 18F-fluoro-deoxy-glucose (18F-FDG) positron emission tomography integrated/combined with computed tomography (PET-CT) provides the best diagnostic results in the metabolic characterization of undetermined solid pulmonary nodules. The diagnostic performance of 18F-FDG is similar for nodules measuring at least 1 cm and for larger masses, but few data exist for nodules smaller than 1 cm. Case presentation: We report five cases of oncologic patients showing focal lung 18F-FDG uptake on PET-CT in nodules smaller than 1 cm. We also discuss the most common causes of 18F-FDG false-positive and false-negative results in the pulmonary parenchyma. In patient 1, contrast-enhanced CT performed 10 days before PET-CT did not show any abnormality in the site of uptake; in patient 2, high-resolution CT performed 1 month after PET showed a bronchiole filled with dense material interpreted as a mucoid impaction; in patient 3, contrast-enhanced CT performed 15 days before PET-CT did not identify any nodules; in patients 4 and 5, contrast-enhanced CT revealed a nodule smaller than 1 cm which could not be characterized. The 18F-FDG uptake at follow-up confirmed the malignant nature of pulmonary nodules smaller than 1 cm which were undetectable, misinterpreted, not recognized or undetermined at contrast-enhanced CT. Conclusion: In all five oncologic patients, 18F-FDG was able to metabolically characterize as malignant those nodules smaller than 1 cm, underlining that: 18F-FDG uptake is not only a function of tumor size but it is strongly related to the tumor biology; functional alterations may precede morphologic abnormalities. In the oncologic population, especially in higher-risk patients, PET can be performed even when the nodules are smaller than 1 cm, because it might give an earlier characterization and, sometimes, could guide in the identification of alterations missed on CT. [ABSTRACT FROM AUTHOR]

Background: 18F-fluoro-deoxy-glucose (18 F-FDG) positron emission tomography integrated/combined with computed tomography (PET-CT) provides the best diagnostic results in the metabolic characterization of undetermined solid pulmonary nodules. The diagnostic performance of 18 F-FDG is similar for nodules measuring at least 1 cm and for larger masses, but few data exist for nodules smaller than 1 cm., Case Presentation: We report five cases of oncologic patients showing focal lung 18 F-FDG uptake on PET-CT in nodules smaller than 1 cm. We also discuss the most common causes of 18 F-FDG false-positive and false-negative results in the pulmonary parenchyma.In patient 1, contrast-enhanced CT performed 10 days before PET-CT did not show any abnormality in the site of uptake; in patient 2, high-resolution CT performed 1 month after PET showed a bronchiole filled with dense material interpreted as a mucoid impaction; in patient 3, contrast-enhanced CT performed 15 days before PET-CT did not identify any nodules; in patients 4 and 5, contrast-enhanced CT revealed a nodule smaller than 1 cm which could not be characterized. The 18 F-FDG uptake at follow-up confirmed the malignant nature of pulmonary nodules smaller than 1 cm which were undetectable, misinterpreted, not recognized or undetermined at contrast-enhanced CT., Conclusion: In all five oncologic patients, 18 F-FDG was able to metabolically characterize as malignant those nodules smaller than 1 cm, underlining that: 18 F-FDG uptake is not only a function of tumor size but it is strongly related to the tumor biology; functional alterations may precede morphologic abnormalities. In the oncologic population, especially in higher-risk patients, PET can be performed even when the nodules are smaller than 1 cm, because it might give an earlier characterization and, sometimes, could guide in the identification of alterations missed on CT.

Lung cancer is the main cause of death from malignancies due to the high prevalence and adverse prognosis when diagnosis is established in symptomatic patients. With early diagnosis, survival is far better; this led to perform some trials of screening in subjects at high risk with chest X-ray since 1970 but outcomes were contrasting. The technological evolution with the introduction of spiral CT and low dose techniques in the last decade led to a new interest in lung cancer screening. Numerous trials were performed and several diagnostic algorithms based on the dimensional and densitometric analysis of CT-evidenced nodules were designed. In spite of the encouraging outcome achieved so far, the high rate of false positives, the high costs and the use of ionizing radiation advise caution at least until a decreased mortality rate from lung cancer is evidenced.

The case of a 39-year-old male patient with symptoms of persistent abdominal pain and melena, affected by Henoch-Schönlein purpura, is reported. Abdominal CT was requested. The examination was justified by the fact that symptoms could be correlated with other pathological conditions (volvulus, neoplasms, Chron's disease, etc.) which had to be excluded. For optimum study of the abdominal wall, correct preparation and the use of oral contrast agents were required. From the analysis of CT findings, in particular loop thickening with stratified density, the increased density of mesenteric fat and the presence of fluid among loops led to the radiological diagnosis of intestinal involvement in Henoch-Schönlein purpura. Other imaging procedures (double contrast enema, sonography, Doppler US, MRI) now used in the study of intestinal loops, are examined.

At present, conventional radiology is being slowly but inexorably replaced by digital radiology. While storage phosphors introduced approximately twenty years ago are now routinely used, flat panel systems are increasingly popular. There are two types of flat panels: those with direct X-ray conversion to electric charge and those where there is initial X photon conversion to visible light from optical amorphous silicon photodiode coupling for conversion to electric charge. The charge is therefore amplified and digital signal conversion is obtained with an analog-to-digital converter. One of the main advantages of Computed Radiography is the separation of image acquisition processing and display. Acquisition systems of digital images with image processing techniques allow the operator to adapt the image characteristics to the clinical requirements. Contrast value and image brightness can be changed soon after acquisition to optimize visualization before printing or transfer to the workstation for postprocessing. Image processing can be interactive, directly on the system consolle. To digital data various processing algorithms can be applied as high spatial frequency enhancement through the construction of the shadow mask. The new digital systems have improved the quality of conventional radiological images as compared to the screen-film and storage phosphor systems with shorter times of procedures and lower exposure dose to patients, while the diagnostic potentialities of the acquired image are enhanced.

Ureteropelvic junction disease is very frequent in pediatric age. Diagnosis is usually established on sonography; in most cases it is prenatal and confirmed at birth. On sonography, hydronephrosis and the site of obstruction is identified with morphofunctional information on renal parenchyma. In the past, urography was the reference examination for ureteropelvic junction disease, but its use is limited in pediatrics especially in prenatal study for radioprotection as well as for the limited glomerular filtration of neonatal kidney. CT and MRI as second level examinations do not find many indications, while angioscintigraphy is largely used to acquire functional data and, in combination with sonography, is basic for diagnosis as well as in follow-up of operated patients.