False positive finding from malignancy-like lesions on FDG PET/CT: case report of tuberculosis patients

Mesorectal thromboembolism with increased 18F-fluorodeoxyglucose uptake during positron emission tomography/computed tomography in a patient with non-small cell lung cancer

This study presents a case of a 72-year-old man diagnosed with non-small cell lung cancer (cT4N0M0) referred to our hospital for possible surgical treatment of a solitary nodule detected in the mesorectum. The patient had received combined chemoradiotherapy and achieved a complete response 13 months before the presentation. On examination, the mesorectal nodule was incidentally detected during surveillance computed tomography, and the maximum standardized uptake value of the nodule was 10.3. Because of the potential malignancy and need for en-bloc resection of the nodule, we performed laparoscopically assisted high anterior resection of the rectum. The postoperative course was uneventful. Notably, while pathological examination revealed that the mesorectal nodule comprised an intravenous organized thromboembolism, malignancy was not observed. These findings suggest that although positron emission tomography/computed tomography with 18F-fluorodeoxyglucose is useful for the diagnosis of malignant diseases, surgical resection might be the most reliable option for complex cases such as ours.

Solitary Periaortic Tuberculous Granuloma Mimicking Neoplastic Disease on 18 F-FDG PET/CT

ABSTRACT

Solitary tuberculoma of periaortic space is extremely rare. We report a case of periaortic tuberculous granuloma revealed by 18 F-FDG PET/CT in a 51-year-old woman without pulmonary or any other organ involvement. Awareness of this rare but possible atypical presentation of tuberculosis is helpful for the differential diagnosis of periaortic mass.

Can High b Value Diffusion Be a Surrogate Marker for PET-A MR/PET Study in Neurooncology Set Up

Purpose: Hybrid whole-body magnetic resonance/positron emission tomography (MR/PET) systems are new diagnostic tools enabling the simultaneous acquisition of morphologic and multiparametric functional data, which allow for a diversified characterization of oncological diseases. This study aimed to compare the diagnostic ability of MRI with the diffusion-weighted image (DWI), and simultaneous integrated positron emission tomography MR/PET to detect malignant lesions and elucidate the utility and limitations of these imaging modalities in preoperative and postoperative follow up in cancer patients. Material and Methods: A total of 45 patients undergoing simultaneous MR/PET for CNS ICSOL in our institution between January 2016 and July 2020 were considered in this study. Post-processing was done in Siemens syngo software to generate a b2000 image. This image was then inverted to grayscale and compared with the NAC image of PET. Results: The lesion-based sensitivity, specificity, positive predictive value, and negative predictive value for DWI were 92.3, 83.3, 97.3, and 62.5%, respectively (at 95% CI and p was 0.000). The lesion-based sensitivity, specificity, positive predictive value, and negative predictive value for PET were 97.4, 71.4, 94.9, and 83.3%, respectively (at 95% CI and p was 0.000). The lesion-based sensitivity and specificity of DWI were comparable with those of PET. Conclusions: Although DWI and FDG-PET reflect different tissue properties, there is an association between the measures of both methods in CNS tumors probably because of the coupling of cellularity with tumor metabolism as seen on FDG and other PET tracers. Our study shows that DWI acts as a surrogate biomarker for FDG PET and other tracers in tumors. The method of DWI image generation is simple, radiation-free, and cost-effective in a clinical setup. The simultaneous DWI-PET study provides evidence and confirms the role of DWI in surveillance imaging of tumors.