No abstract

Purpose This study retrospectively reviews the characteristic bone scintigraphic findings in 18 patients with hepatocellular carcinoma (HCC) following treatment with high-intensity focused ultrasound (HIFU). A potential complication of HIFU is damage to the tissues along the path of the ultrasound beam and structures superficial to the lesion of interest. Methods Patients with hepatocellular carcinoma who underwent a bone scan between 1st December 2005 and 31st December 2011 were considered for this study. Among these patients, only those who had bone scans after the HIFU treatment were included. The time between HIFU treatment and bone scans, HIFU energy, HCC sites, tumour sizes and related radiological findings were evaluated. Results In total, 20 bone scans of 18 patients were reviewed. Of these scans, two patients were normal; three patients showed decreased uptake, four patients showed increased uptake and nine patients showed mixed uptakes of the bony tracer in their rib cages. The defects were located in the anterior, lateral, anterolateral or posterolateral aspects of the rib cage. The majority of those cold defects were in the right anterior rib cages. SPECT/CT was used to localise the decreased uptake in ribs. The magnetic resonance imaging in individual patients invariably showed ill-defined rim enhancement along the right chest wall, signifying chest wall injury. Conclusions The results showed that tissue ablation using HIFU caused tissue injury along the pathway of highintensity ultrasound beams. The harm to tissues is presented as photopenic area on the rib cages due to necrosis or hot spots due to rib fractures in the bone scan. Since these cold defects are subtle, they are easily overlooked or mistaken as aggressive bony metastasis.

Changes in cerebral glucose metabolism after subarachnoid hemorrhage have been rarely described. We present a case with subacute subarachnoid hemorrhage showing unexpected elevated FDG uptake at adjacent cerebral parenchyma on FDG PET/CT. The density of the cerebral parenchyma was normal on CT. The patient received medical management without any neurological complication.

Epiphora, an abnormal overflow of tears, is commonly caused by tear drainage system anomalies including nasolacrimal duct obstruction. To evaluate the function of the system, dacryoscintigraphy is a commonly available non-invasive method under a nuclear medicine dynamic acquisition. We recommend the use of SPECT/CT after the dynamic acquisition to localize the obstruction site and to differentiate that tear overflow is not due to radiation contamination as sometimes encountered in dacryoscintigraphy. A case is presented to support the use of SPECT/CT in the protocol.