Value of Thallium-201 SPECT and SPECT/CT Brain Imaging in Differentiating Malignant From Nonmalignant Lesions: A Comparative Case-Series Study With Pathologic and/or Clinical Correlation.

BACKGROUND: Thallium-201 single-photon emission computed tomography/computed tomography (SPECT/CT) brain scan is an imaging modality which can be done to differentiate between malignant and nonmalignant lesions among patients with nonconclusive findings on conventional neuroimaging. This study describes the results of thallium-201 SPECT/CT brain imaging and relate it to histopathologic and/or clinical findings and evaluate the value of thallium-201 SPECT/CT brain imaging in differentiating malignant from nonmalignant lesions. METHODS: This is a retrospective case series study of 10 patients with cerebral lesions who underwent thallium-201 SPECT/CT brain imaging in a hospital in the Philippines from 2010 to 2021. RESULTS: A total of 10 patients underwent thallium-201 SPECT/CT brain scan. Six had negative results while 4 had positive results. All of the patients who had positive results were found to have malignancy, whether recurrent or newly diagnosed. All of the patients with negative scan were found to have either an infectious and inflammatory disease and responded to treatment albeit in different degrees. Two of the 10 patients underwent biopsy whose results were consistent with the thallium-201 SPECT/CT brain scan results. CONCLUSION: Thallium-201 brain scan combined with SPECT and SPECT/CT has been demonstrated to be useful in distinguishing malignant from nonmalignant lesions and is more cost-effective versus other imaging techniques. The findings in this study support the role of thallium scintigraphy in the diagnosis of patients with brain lesions most significantly when there is a need to differentiate between a malignant and benign condition.

Value of radiologic correlation and follow-up scintigraphy in detecting osseous metastasis in patients with non-specific bone scintigraphy lesions

Bone scintigraphy is highly sensitive in detecting bone metastasis but specificity is only about 50-60%. The aim of this study is to evaluate the value of radiologic correlation and followwup scintigraphy in detecting osseous metastasis in patients with equivocal bone scans. Bone scan results with non-specific interpretation of bone lesions from January to December 2007 were included. Results with no evidence of bone metastasis or metastatic bone disease were excluded from the study. Correlation with radiographs [X-ray, CT-scan, MRI] and follow-up bone scan within 6 months from the initial bone scan were reviewed. Of the 2322 bone scans, 435 have non-specific findings of bone lesions. From 435, only 228 patients have records of radiograph correlation and scintigraphic follow-up. Twenty two percent of the total population showed positive findings of bone metastasis in radiographs. The percentages of the non-specific findings determined to be negative from bone metastasis on correlation with X-ray, CT-scan, MRI and follow-up bone scan were 84%, 70%,73%, and 85%, respectively, whereas osseous metastasis revealed on radiologic correlation and follow-up scan were 76%, 30%,27%, and 75%, respectively. In conclusion, the finding of osseous metastasis in bone scan is increased when correlated with radiographs and scintigraphic follow-up.

Metastatic thyroid carcinoma in the kidney

Thyroid carcinoma, particularly papillary thyroid carcinoma, may present with a wide range of clinical course--from an indolent to an aggressive form of poorly differentiated thyroid carcinoma. About 10% of patients with papillary thyroid cancer develop distant metastasis to the lymph nodes, lungs, mediastinum, or bone. Several cases of unusual metastasis to the kidney have been reported previously. A rare case of renal metastasis from papillary thyroid carcinoma and the roles of PET and SPECT-CT in its detection are presented here.