Present and future roles of FDG-PET/CT imaging in the management of lung cancer

Integrated positron emission tomography/computed tomography (PET/CT) using 2-[¹⁸F]fluoro-2-deoxy-d-glucose (¹⁸F-FDG) has emerged as a powerful tool for combined metabolic and anatomic evaluation in clinical oncologic imaging. This review discusses the utility of ¹⁸F-FDG PET/CT as a tool for managing patients with lung cancer. We discuss different patient management stages, including diagnosis, initial staging, therapy planning, early treatment response assessment, re-staging, and prognosis.     

Imaging spectrum and pitfalls of 18F-fluorodeoxyglucose positron emission tomography/computed tomography in patients with tuberculosis

Mycobacterium tuberculosis (TB) is one of the most prominant diseases frequently causing false positive lesions in oncologic surveys using ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT), since TB granulomas are composed of activated macrophages and lymphocytes with high affinity for glucose. These pitfalls of ¹⁸F-FDG PET/CT are important for radiologists. Being familiar with ¹⁸F-FDG images of TB could assist in preventing unfavorable clinical results based on misdiagnoses. In addition, ¹⁸F-FDG PET/CT has the advantage of being able to screen the whole body, and can clearly detect harboring TB lesions as high uptake foci. This article details the spectrum and pitfalls of ¹⁸F-FDG PET/CT imaging in TB.     

Pictorial review of <Superscript>18</Superscript>F-FDG PET/CT findings in musculoskeletal lesions

We herein reviewed ¹⁸F-fluoro-2-deoxyglucose (¹⁸F-FDG) positron emission tomography (PET)/computed tomography (CT) findings in a number of musculoskeletal lesions including malignant tumors, benign tumors, and tumor-like lesions with correlations to other radiographic imaging modalities, and described the diversity of the ¹⁸F-FDG PET/CT findings of this entity. Malignant primary musculoskeletal tumors are typically ¹⁸F-FDG avid, whereas low-grade malignant tumors show mild uptake. Benign musculoskeletal tumors generally show a faint uptake of ¹⁸F-FDG, and tumor-like conditions also display various uptake patterns of ¹⁸F-FDG. Although musculoskeletal tumors show various uptakes of ¹⁸F-FDG on PET/CT, its addition to morphological imaging modalities such as CT and MRI is useful for the characterization and differentiation of musculoskeletal lesions.     

Small Cell Carcinoma of the Gallbladder: 18F-FDG PET/CT Imaging Features—A Case Report

The diagnostic role of ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET)/computed tomography (CT) for gallbladder small cell carcinoma has not been reported. A knowledge of the imaging characteristic features of this malignancy can be useful. Here we report a rare case of a patient who had various diagnostic imaging modalities, including ¹⁸F-FDG PET/CT.     

<Superscript>68</Superscript>Gallium-Arginine-Glycine-Aspartic Acid and <Superscript>18</Superscript>F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in Chondroblastic Osteosarcoma of the Skull

We report the case of a 32 year-old male with Chondroblastic Osteosarcoma of the skull, which was imaged with both ¹⁸[F]fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) and ⁶⁸Gallium-arginine-glycine-aspartic acid (⁶⁸Ga-RGD) PET/CT. The ¹⁸F-FDG PET/CT did not demonstrate the tumour, whereas the ⁶⁸Ga-RGD PET/CT clearly depicted a left-sided frontal tumour. ⁶⁸Ga-RGD PET/CT may be a clinically useful imaging modality for early detection of recurrent osteosarcoma, considering the limitations of ¹⁸F-FDG PET in a setting of low glycolytic activity.     

Primary Renal Leiomyosarcoma Presenting with Subcutaneous and Osseous Metastases: Staging and Follow-Up with 18F-FDG PET/CT

A 60 year old woman who presented with multiple small subcutaneous nodules in the upper back and arms, was referred for an [18F] fluoro-2-deoxy-D-glucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) after histological evaluation revealed metastatic leiomyosarcoma of unknown origin. The PET/CT showed multiple ¹⁸F-FDG-avid subcutaneous nodules, bone lesions, as well as a large left renal mass, which was biopsied to confirm a primary renal leiomyosarcoma arising from the renal parenchyma. A post therapy PET/CT showed overall progression of disease. The use of ¹⁸F-FDG PET/CT in the staging and evaluation of response to therapy of a renal leiomyosarcoma has not been previously described in the literature.     

Nonfunctioning endocrine pancreatic tumor examined with 18F-FDG PET/CT

A 71-year-old woman with type 2 diabetes mellitus complained of generalized fatigue. A 36-mm tumor in the pancreatic tail was detected with ultrasonography. The tumor was found to have marked hypervascularity with contrast-enhanced computed tomography (CT) and magnetic resonance. Combined ¹⁸F-fluorodeoxyglucose positron emission tomography and CT (¹⁸F-FDG PET/CT) showed ¹⁸F-FDG by the tumor with a maximal standardized uptake value of 2.98 at 50 min and 3.29 at 100 min following injection of ¹⁸F-FDG. ¹⁸F-FDG PET/CT suggested no extrapancreatic spread of the tumor. The patient had no pancreatic hormone-associated symptoms. Distal pancreatectomy was performed, and a well-differentiated endocrine tumor was diagnosed. The resected specimen showed neither infiltration of adjacent structures nor metastasis to regional lymph nodes. The present case suggests that ¹⁸F-FDG PET/CT is a reliable modality for staging endocrine pancreatic tumors.     

The role of F-FDG PET or PET/CT in the detection of fever of unknown origin

Even with the recent advance in diagnostic tools and techniques, fever of unknown origin (FUO) remains a clinical challenge. A wide range of diseases, mainly infections, autoimmune conditions (inflammatory diseases), malignancies and miscellaneous can cause FUO. Positron emission tomography (PET) or positron emission tomography/computed tomography (PET/CT) scanning makes a great contribution to the diagnosis and differential diagnosis of FUO due to the high sensitivity of pathological accumulation of ¹⁸F-FDG. The diagnostic yield of PET/CT is higher than traditional radiographic imaging and other nuclear medicine scanning. Owing to the numerous advantages of PET/CT including high sensitivity and the ability to perform whole-body scans, many rare diseases presenting with FUO can be detected and the spectrum of diseases that can exhibit FUO has been increasing. Recent studies utilizing FUO are discussed in this paper. However, there are limited data available about the role of ¹⁸F-FDG PET or PET/CT in evaluation of FUO.     

Imaging findings of primary malignant gastrointestinal stromal tumor of the liver

A primary gastrointestinal stromal tumor (GIST) arising in the liver is extremely rare. In our case of GIST, CT and MRI showed a well-defined, weakly enhancing mass with a cystic component in the left lateral segment of the liver that showed homogeneous and avid ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) accumulation on positron emission tomography/computed tomography (PET/CT). We herein present a rare case of primary malignant GIST of the liver presenting with peritoneal seeding on CT, gadoxetic acid-enhanced MRI and ¹⁸F-FDG PET/CT.     

18F-FDG PET/CT in detection of gynecomastia in patients with hepatocellular carcinoma

ObjectiveWe retrospectively investigate the prevalence of gynecomastia as false-positive 2-[¹⁸F]fluoro-2-deoxy-d-glucose (¹⁸F-FDG) positron emission tomography (PET)/computed tomography (CT) imaging in patients with hepatocellular carcinoma (HCC).MethodsAmong the 127 male HCC patients who underwent ¹⁸F-FDG PET/CT scan, the ¹⁸FDG uptakes at the bilateral breasts in 9 patients with gynecomastia were recorded as standard uptake value (SUVmax) and the visual interpretation in both early and delayed images.ResultsThe mean early SUVmax was 1.58/1.57 (right/left breast) in nine gynecomastia patients. The three patients with early visual score of 3 had higher early SUVmaxs.ConclusionGynecomastia is a possible cause of false-positive uptake on ¹⁸F-FDG PET/CT images.     

18F-FDG PET/CT in Primary AL Hepatic Amyloidosis Associated with Multiple Myeloma

We report here on a rare case of primary AL hepatic amyloidosis associated with multiple myeloma in a 64-year-old woman. The patient was referred for evaluating her progressive jaundice and right upper quadrant pain. ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET)/computed tomography (CT) showed diffusely and markedly increased ¹⁸F-FDG uptake in the liver. Although there have been several case studies showing positive ¹⁸F-FDG uptake in pulmonary amyloidosis, to the best of our knowledge, the ¹⁸F-FDG PET/CT findings of hepatic amyloidosis or primary hepatic amyloidosis associated with multiple myeloma have not been reported previously.     

Primary Malignant Fibrous Histiocytoma in Mediastinum: Imaging with 18F-FDG PET/CT

Malignant fibrous histiocytoma (MFH) is the most common soft tissue tumor which often occurs in the extremities and the retroperitoneum. Primary mediastinal MFH is rare; thus, findings on ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) of mediastinal MFH have not been reported yet. We report herein the case of a 64-year-old man who was presented with a superior mediastinal mass. The mass showed intense ¹⁸F-FDG uptake with central metabolic defect on PET/CT. The maximum standardized uptake value was 17.4. After tumor removal via median sternotomy, an MFH of the storiform-pleomorphic type was diagnosed on histopathologic examination. We present the first report of ¹⁸F-FDG PET/CT imaging of MFH in the superior mediastinum.     

18F-FDG PET/CT Findings in a Breast Cancer Patient with Concomitant Tuberculous Axillary Lymphadenitis

Although ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET) is a sensitive modality for detecting a malignant lesion, increased ¹⁸F-FDG uptake is also seen in infected or inflammatory processes. Here, we report the case of a breast cancer patient with concomitant tuberculous axillary lymphadenitis that showed increased ¹⁸F-FDG uptake. A 39-year-old woman underwent preoperative ¹⁸F-FDG PET/computed tomography (CT) as a part of the work-up for right breast cancer. ¹⁸F-FDG PET/CT images showed a malignant lesion in the right breast with moderate ¹⁸F-FDG uptake, and multiple enlarged right axillary lymph nodes with intense ¹⁸F-FDG uptake. Subsequently, the patient underwent right mastectomy and right axillary lymph node dissection. Histopathological examination confirmed breast cancer and tuberculous lymphadenitis, and the patient was treated concomitantly with anti-tuberculous therapy.     

Bilateral Tubo-Ovarian Abscess Mimics Ovarian Cancer on MRI and 18F-FDG PET/CT

A 20-year-old woman, who presented with a several-week history of abdominal pain, was referred for magnetic resonance imaging (MRI) and ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) after an ultrasound showed complex cystic masses arising from both ovaries. The MRI and ¹⁸F-FDG PET/CT imaging characteristics of the ovarian masses were strongly suspicious for malignancy, and the masses were surgically removed. Histopathological evaluation revealed a bilateral tubo-ovarian abscess, with no evidence of malignancy. This case highlights a potentially serious pitfall in the evaluation of suspicious pelvic masses by ¹⁸F-FDG PET/CT, whereby a complex bilateral tubo-ovarian abscess may mimic the PET/CT imaging characteristics of an ovarian or pelvic malignancy.     

Usefulness of <Superscript>18</Superscript>F-FDG PET/CT to Detect Metastatic Mucinous Adenocarcinoma Within an Inguinal Hernia

Metastatic mucinous adenocarcinoma in an inguinal hernia is a rare disease and the image findings of ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET)/computed tomography (CT) are little known. Here, we introduce a 57-year-old man with metastatic mucinous adenocarcinoma in an inguinal hernia. On initial ¹⁸F-FDG PET/CT, hypermetabolism was observed in mucinous adenocarcinoma of the cecum, and adenocarcinomas of the transverse and ascending colon, respectively. Follow-up ¹⁸F-FDG PET/CT revealed newly developed multiple hypermetabolism in peritoneal seeding masses and nodules in the pelvic cavity and scrotum. Peritoneal carcinomatosis in the right pelvic side wall was extended to the incarcerated peritoneum and mesentery in the right inguinoscrotal hernia.¹⁸F-FDG PET/CT was useful to reveal unexpected peritoneal seeding within the inguinal hernia. Also, this case demonstrated that metastatic mucinous adenocarcinomas had variably intense FDG uptake.     

Multifocal Colonic Lesions Detected by 18F-FDG PET/CT: Correlation with Histopathology and Gross Specimen

A 73-year-old man underwent ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) for the staging of colon cancer. The ¹⁸F-FDG PET/CT revealed three colonic lesions. The histopathologic examination of the postoperative gross specimen revealed a tubular adenoma, a tubulovillous adenoma and an adenocarinoma. The maximal standardized uptake value (SUVmax) of a tubulovillous adenoma was much higher than that of adenocarcinoma. This patient could be considered as a representative case highlighting that SUVmax is not a reliable indicator for discriminating colon cancer from colonic adenomas.     

18F-FDG PET/CT in suspected recurrences of epithelial malignant pleural mesothelioma in asbestos-fibers-exposed patients (comparison to standard diagnostic follow-up)

This retrospective study evaluated the role of 18-fluorine-labeled 2-deoxy-2-fluoro-d-glucose positron emission tomography/computed tomography (18F-FDG PET/CT) in patients with previous occupational or environmental exposure to asbestos, with histopathological diagnosis of epithelial malignant pleural mesothelioma and suspected recurrences, comparing the data from 18F-FDG PET/CT and computed tomography with contrast enhancement (CECT). 18F-FDG PET/CT has greater sensitivity than CECT in identifying local extent, lymph nodes, and metastasis. 18F-FDG PET/CT whole-body explorations are useful to monitor the follow-up and evaluate the metabolic response to chemo- and radiotherapy, modifying the scheduled treatment plan.     

Comparison of 68Ga-DOTATATE and 18F-fluorodeoxyglucose PET/CT in the detection of recurrent medullary thyroid carcinoma

Purpose  

This was a retrospective study to detect and map the extent of disease in recurrent medullary thyroid carcinoma (MTC) using the novel PET somatostatin analogue ⁶⁸Ga-DOTATATE and conventional ¹⁸F-FDG positron emission tomography/computed tomography (PET/CT).     

Late Port Site Metastasis from Occult Gall Bladder Carcinoma After Laparoscopic Cholecystectomy for Cholelithiasis: The Role of 18F-FDG PET/CT

Late port site metastasis of gall bladder carcinoma (GBC) after laparoscopic cholecystectomy is a rare finding. Rarer still is such a presentation where the GBC remained occult at histopathology. ¹⁸F-flurodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) can play an important role in this setting by supporting the diagnosis of port site metastasis, by demonstrating additional sites of metastasis, if any, and by ruling out any other primary site. We here present two such patients with late port site metastasis of occult GBC after laparoscopic cholecystectomy for cholelithiasis and discuss the role of ¹⁸F-FDG PET/CT in this setting.     

Intraosseous hemangioma arising in the clavicle

Intraosseous hemangioma (IH) is commonly seen in the vertebral column and skull: however, IH occurring in the appendicular skeleton, including the clavicle, is uncommon. We herein report the case of a 69-year-old female presenting with IH of the left clavicle. The findings of preoperative imaging studies, including radiographs, computed tomography (CT), magnetic resonance imaging, fluorine-18-fludeoxyglucose (¹⁸F-FDG) positron emission tomography (PET)/CT and ultrasonography, are described. In particular, ¹⁸F-FDG PET/CT showed an ill-defined osteolytic lesion with abnormally high FDG uptake. Surgical en bloc resection with preoperative embolization was carried out and a histopathological examination confirmed the presence of an intraosseous cavernous hemangioma in the clavicle.