Value of FDG PET/Contrast-Enhanced CT in Initial Staging of Colorectal Cancer - Comparison with Contrast-Enhanced CT

Kunawudhi, Anchisa,Sereeborwornthanasak, Karun,Promteangtrong, Chetsadaporn,Siripongpreeda, Bunchorn,Vanprom, Saiphet,Chotipanich, Chanisa Asian Pacific Journal of Cancer Prevention 2016 Asian Pacific journal of cancer prevention Vol.17 No.8

Background: FDG PET/CT is at an equivocal stage to recommend for staging of colorectal cancer as compared to contrast-enhanced CT (ceCT). This study was intended to evaluate the value of FDG PET/ceCT in colorectal cancer staging as compared to ceCT alone. Materials and Methods: PET/ceCT was performed for 61 colorectal cancer patients who were prospectively enrolled in the study. Three patients were excluded due to loss to follow-up. PET/ceCT findings and ceCT results alone were read separately. The treatment planning was then determined by tumor board consensus. The criteria for T staging were determined by the findings of ceCT. Nodal positive by PET/ceCT imaging was determined by visual analysis of FDG uptake greater than regional background blood pool activity. The diagnostic accuracy of T and N staging was determined only in patients who received surgery without any neoadjuvant treatment. Results: Of 58 patients, there were 40 with colon cancers including sigmoid cancers and 18 with rectal cancers. PET/ceCT in pre-operative staging detected bone metastasis and metastatic inguinal lymph nodes (M1a) that were undepicted on CT in 2 patients (3%), clearly defined 19 equivocal lesions on ceCT in 18 patients (31%) and excluded 6 metastatic lesions diagnosed by ceCT in 6 patients (10%). These resulted in alteration of management plan in 15 out of the 58 cases (26%) i.e. changing from chemotherapy to surgery (4), changing extent of surgery (9) and avoidance of futile surgery (2). Forty four patients underwent surgery within 45 days after PET/CT. The diagnostic accuracy for N staging with PET/ceCT and ceCT alone was 66% and 48% with false positive rates of 24% (6/25) and 76% (19/25) and false negative rates of 47% (9/19) and 21% (4/19), respectively. All of the false negative lymph nodes from PET/ceCT were less than a centimeter in size and located in peri-lesional regions. The diagnostic accuracy for T staging was 82%. The sensitivity of the peri-lesional fat stranding sign in determining T3 stage was 94% and the specificity was 54%. Conclusions: Our study suggested promising roles of PET/ceCT in initial staging of colorectal cancer with better diagnostic accuracy facilitating management planning.

Accuracy of FDG-PET/CT for Detection of Incidental Pre-Malignant and Malignant Colonic Lesions - Correlation with Colonoscopic and Histopathologic Findings

Kunawudhi, Anchisa,Wong, Alexandra K,Alkasab, Tarik K,Mahmood, Umar Asian Pacific Journal of Cancer Prevention 2016 Asian Pacific journal of cancer prevention Vol.17 No.8

Purpose: We evaluated all PET/CTs acquired for patients without a primary diagnosis of colorectal cancer, and compared results for those who had subsequent colonoscopy within 6 months, to assess the accuracy of FDG PET/CT for detection of incidental pre-malignant polyps and malignant colon cancers. Materials and Methods: Medical records of 9,545 patients who underwent F-18 FDG PET/CT studies over 3.5 years were retrospectively reviewed. Due to pre-existing diagnosis of colorectal cancer, 818 patients were excluded. Of the remainder, 157 patients had colonoscopy within 6 months (79 males; mean age 61). We divided the colon into 4 regions and compared PET/CT results for each region with colonoscopy and histopathologic findings. True positive lesions included colorectal cancer, villous adenoma, tubulovillous adenoma, tubular adenoma and serrated hyperplastic polyp/hyperplastic polyposis. Results: Of 157 patients, 44 had incidental colonic uptake on PET/CT (28%). Of those, 25 had true positive (TP) uptake, yielding a 48% positive predictive value (PPV); 9% (4/44) were adenocarcinoma. There were 23 false positive (FP) lesions of which 4 were hyperplastic polyp, one was juvenile polyp and 7 were explained by diverticulitis. Fifty eight patients had false negative PET scans but colonoscopy revealed true pre-malignant and malignant pathology, yielding 23% sensitivity. The specificity, negiative predictive value (NPV) and accuracy were 96%, 90% and 87%, respectively. The average SUVmax values of TP, FP and FN lesions were 7.25, 6.11 and 2.76, respectively. There were no significant difference between SUVmax of TP lesions and FP lesions (p>0.95) but significantly higher than in FN lesions (p<0.001). The average size (by histopathology and colonoscopy) of TP lesions was 18.1 mm, statistically different from that of FN lesions which was 5.9 mm (p<0.001). Fifty-one percent of FN lesions were smaller than 5 mm (29/57) and 88% smaller than 10 mm (50/57). Conclusions: The high positive predictive value of incidental focal colonic FDG uptake of 48% for colonic neoplasia suggests that colonoscopy follow-up is warranted with this finding. We observed a low sensitivity of standardly acquired FDG-PET/CT for detecting small polyps, especially those less than 5 mm. Clinician and radiologists should be aware of the high PPV of focal colonic uptake reflecting pre-malignant and malignant lesions, and the need for appropriate follow up.

Diagnosis of Hepatocellular Carcinoma Using C-11 Choline PET/CT: Comparison with F-18 FDG, Contrast-Enhanced MRI and MDCT

Chotipanich, Chanisa,Kunawudhi, Anchisa,Promteangtrong, Chetsadaporn,Tungsuppawattanakit, Puntira,Sricharunrat, Thaniya,Wongsa, Paramest Asian Pacific Journal of Cancer Prevention 2016 Asian Pacific journal of cancer prevention Vol.17 No.7

Purpose: The aim of this study was to compare C-11 choline and F-18 FDG PET/CT, gadoxetic-enhanced 3-T MRI and contrast-enhanced CT for diagnosis of hepatocellular carcinoma (HCC). Materials and Methods: Twelve chronic hepatitis B patients suspected of having HCC by abdominal ultrasonography received all diagnostic modalities performed within a one-week timeslot. PET/CT results were analyzed visually by two independent nuclear medicine physicians and quantitatively by tumor to background ratio (T/B). Nine patients then had histopathological confirmation. Results: Six patients had well differentiated HCC, while two and one patient(s) were noted with moderately and poorly differentiated HCC, respectively. All were detected by both CT and MRI with an average tumor size of $5.7{\pm}3.8cm$. Five patients had positive C-11 choline and F-18 FDG uptake. Of the remaining four patients, three with well differentiated HCC showed negative F-FDG uptake (one of which showed negative results by both tracers) and one patient with moderately differentiated HCC demonstrated no C-11 choline uptake despite intense F-18 FDG avidity. The overall HCC detection rates with C-11 choline and F-18 FDG were 78% and 67%, respectively, while the sensitivity of F-18 FDG for non-well differentiated HCC was 100%, compared with 83% of C-11 choline. The average T/B of C-11 choline in well-differentiated HCC patients was higher than in moderately and poorly differentiated cases (p=0.5) and vice versa with statistical significance for T/B of F-18 FDG (p = 0.02). Conclusions: Our results suggested better detection rate in C-11 choline for well differentiated HCC than F-18 FDG PET. However, the overall detection rate of PET/CT with both tracers could not compare with contrast-enhanced CT and MRI.

68Ga-FAPI-46 PET/MR Detects Recurrent Cholangiocarcinoma and Intraductal Papillary Mucinous Neoplasm in a Patient Showing Increasing CEA with Negative 18F-FDG PET/CT and Conventional CT

Dheeratama Siripongsatian,Promteangtrong Chetsadaporn,Kunawudhi Anchisa,Kiatkittikul Peerapon,Chotipanich Chanisa 대한핵의학회 2021 핵의학 분자영상 Vol.55 No.5

A patient with intrahepatic cholangiocarcinoma who underwent hepatic resection with completed neoadjuvant chemotherapy presented with increased CEA levels. Previous whole abdominal and chest CT scan revealed no evidence of local recurrence or metastasis. 68 Ga-FAPI-46 PET showed significantly higher tumor-to-background contrast of recurrent tumor and nodal metastasis, which were undetectable in the FDG PET or conventional CT scan. These findings changed patient management. Larger studies with histopathological correlation and comparisons with other imaging modalities are required to validate the diagnostic performance. Moreover, a cystic lesion with FAPI uptake at the neck to the proximal body of the pancreas without FDG uptake is also incidentally noted. Differential diagnoses include sided branch IPMN and serous cystadenoma.

Abnormality Pattern of F-18 FDG PET Whole Body with Functional MRI Brain in Post-Acute COVID-19

Kiatkittikul Peerapon,Promteangtrong Chetsadaporn,Kunawudhi Anchisa,Dheeratama Siripongsatian,Taweegrit Siripongboonsitti,Piyanuj Ruckpanich,Supachoke Thongdonpua,Attapon Jantarato,Chaiyawat Piboonvor 대한핵의학회 2022 핵의학 분자영상 Vol.56 No.1

Purpose The study aimed to investigate imaging abnormalities associated with post-acute COVID-19 using F-18 FDG PET/ CT and PET/ rsfMRI brain. Methods We retrospectively recruited 13 patients with post-acute COVID-19. The post-acute COVID-19 symptoms and neuropsychiatric tests were performed before F-18 FDG PET/CT whole body with PET/rsfMRI brain. Qualitative and semiquantitative analyses were also conducted in both whole body and brain images. Results Among the 13 patients, 8 (61.5%) had myositis, followed by 8 (61.5%) with vasculitis (mainly in the thoracic aorta), and 7 (53.8%) with lung abnormalities.. Interestingly, one patient with a very high serum RBD IgG antibody demonstrated diffuse myositis throughout the body which potentially associated with immune-mediated myositis. One patient experienced psoriasis exacerbation with autoimmune-mediated after COVID-19. Most patients had multiple areas of abnormal brain connectivity involving the frontal and parieto-temporo-occipital lobes, as well as the thalamus. Conclusion The whole body F-18 FDG PET can be a potential tool to assess inflammatory process and support the hyperinflammatory etiology, mainly for lesions in skeletal muscle, vascular wall, and lung, as well as, multiple brain abnormalities in post-acute COVID-19. Nonetheless, further studies are recommended to confirm the results.