Hiromichi Uchisako

High resolution CT findings in community-acquired pneumonia

PURPOSE Our goal was to clarify the high resolution CT (HRCT) findings of community-acquired pneumonia based on pathologic findings and to make a differential diagnosis between bacterial and atypical pneumonias. METHOD This study evaluated 32 cases with community-acquired pneumonia, including 18 cases with bacterial pneumonia and 14 cases with atypical pneumonia [mycoplasma pneumonia (n = 12), chlamydia pneumonia (n = 1), and influenza viral pneumonia (n = 1)]. HRCT images in these cases were space consolidation, ground-glass attenuation, thickening of the bronchovascular bundle, and distribution of abnormal attenuation. RESULTS Bacterial pneumonia frequently showed air space consolidation with segmental distribution (72.2%) that tended to locate at the middle and outer zones of the lung. Atypical pneumonia frequently showed centrilobular shadow (64.3%), acinar shadow (71.4%), air space consolidation and ground-glass attenuation with lobular distribution (57.1 and 85.7%, respectively), and tendency of the lesions to distribute at the inner layer of the lung in addition to the middle and outer layers (85.7%). CONCLUSION Characteristic HRCT findings of both bacterial and atypical pneumonia were demonstrated. These HRCT features seemed to reflect pathologic findings and the manner of lesional progression. This information may support the appropriate antibiotic therapy in medical practice.

Abnormal extrapulmonary accumulation of99mTc-MAA during lung perfusion scanning

We present fourteen patients with an abnormal extrapulmonary accumulation on lung perfusion scintigraphy with99mTc-macroaggregated albumin (MAA), who were examined during the last decade. These included six patients with lung cancer, four with pulmonary arterio-venous fistula, two with congenital heart disease, one with inferior vena cava (IVC) syndrome and one with congenital bronchogenic cyst. All six patients with lung cancer had superior vena cava (SVC) syndrome, and the tumor invaded the thoracic wall.As causes of abnormal accumulation, fourteen patients had a right-to-left shunt, and one patient with IVC syndrome had a systemic vein-to-portal vein shunt, and one patient with lung cancer associated with superior vena cava (SVC) syndrome had both right-to-left and systemic vein-to-portal vein shunts. In the two patients with systemic vein-to-portal vein shunts, a hot spot was observed at the hepatic hilum, and radionuclide venography revealed remarkably developed collateral pathways to the portal vein. An extrapulmonary accumulation seen on99mTc-MAA lung perfusion scan therefore indicates the existence of unusual hemodynamics with a shunt. We should therfore be careful not to overlook this peculiar finding.

Delayed restoration of lung perfusion after removal of aspirated foreign body.

Tc-99m MAA lung scan contributed to the diagnosis of an aspirated endobronchial foreign body in a 2-year-old boy, although there was no radiographic evidence of obstruction. Despite the complete removal of the foreign-body, a follow-up scan performed 8 days after removal demonstrated incomplete restoration of perfusion to the ipsilateral lung. It is not easy to explain this delayed improvement of hypoperfuslon, but it may reflect a slow recovery of reflex vasoconstriction with a partial bronchial obstruction, or it may reflect reduced perfusion caused by persistent, subclinical inflammatory changes in the peripheral lung.

Thin-section oblique CT with 25° cranially tilted images Evaluation of pulmonary tumors adjacent to the interlobar fissures

Purpose: Thin-section oblique CT with cranially tilted axial scans can provide better visualization of the interlobar fissures than thin-section CT with conventional axial scans. the purpose of this study was to evaluate the usefulness of oblique CT scans for pulmonary tumors adjacent to the interlobar fissures. Material and Methods: Cranially tilted and conventional axial images were obtained by thin-section CT in 10 patients with solitary pulmonary tumors adjacent to the interlobar fissures. Conventional CT with a 2-mm collimation and thin-section oblique CT with a 25° cranial tilt were obtained. Results: the images obtained by thin-section oblique scanning visualized the relationship between the pulmonary tumor and the interlobar fissures in all 10 patients, whereas in 6 patients the thin-section conventional images did not. the pulmonary tumors in these 6 patients included all 5 that were adjacent to the minor fissures. Conclusion: Thin-section oblique CT may be more useful than thin-section conventional CT in evaluating the relationship between pulmonary tumors and the minor fissures.

Preliminary Tl-201 SPECT for assessment of treatment efficacy in three patients with pancreatic cancer.

To evaluate treatment efficacy, Tl-201 SPECT was performed in three patients with pancreatic cancer. In all of the patients, the degree of Tl-201 uptake by tumor, evaluated from the tumor-liver uptake ratio of Tl-201 activity, correlated well with alterations in serum level of a tumor marker (CA 19-9, DUPAN-2) after treatment. One of the patients showed no tumor shrinkage on CT after treatment; however, Tl-201 SPECT demonstrated reduced uptake in the tumor coupled with a decreased level of CA 19-9. These results suggest that Tl-201 SPECT may become a new tool for assessing the efficacy of treatment in pancreatic cancer.