FDG uptake in abdominal mesh implant on FDG PET/CT

A 50-year-old man with peritoneal angiosarcoma underwent total tumor excision along with removal of the total right rectus and medial part of the left rectus muscles 1 year earlier. F-18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) was performed for suspected recurrence. In the anterior abdominal wall extensive subcutaneous FDG uptake showing linear hypermetabolic zone on PET slices was noted. The patient had a history of a dual mesh implant, which consists of polypropylene and polyvinylidene fluoride for the reinforcement of the abdominal wall during the operation. PET/CT fusion image demonstrated that the finding was due to the dual mesh implant in the anterior abdominal wall most likely representing a foreign body reaction.     

Distribution of F-18 fluorodeoxyglucose (F-18 FDG) in abdominal aortic aneurysm: high accumulation in macrophages seen on PET imaging and immunohistology

A 68-year-old man was hospitalized for unstable angina and underwent emergency coronary artery bypass surgery. During the operation, a pulsatile large abdominal aortic aneurysm (AAA) was discovered. To define the optimal treatment of the abdominal aneurysm, after bypass surgery, CT scans and positron emission tomography (PET) were performed, as we routinely do. PET imaging combined with immunohistologic examination showed a region of increased F-18 FDG uptake corresponding to an inflammatory infiltrate in the aortic wall in contrast to the thrombus in the aneurysm (devoid of inflammatory cells). The luminal area showed midlevel F-18 FDG uptake corresponding to circulating mediators.     

A Case of Acute Q Fever Hepatitis Diagnosed by F-18 FDG PET/CT

A 53-year-old man with fever of unknown origin underwent F-18 fluorodeoxyglucose positron emission tomography/computed tomography (F-18 FDG PET/CT) as a workup for a fever of unknown origin. On presentation, he complained of fever, chills, and myalgia. The F-18 FDG PET/CT scan showed diffusely increased uptake of the liver with mild hepatomegaly. A liver biopsy then revealed fibrin-ring granulomas typically seen in Q fever. The patient was later serologically diagnosed as having acute Q fever as the titers for C. burnetii IgM and IgG were 64:1 and 16:1, respectively. He recovered completely following administration of doxycycline. This indicates that F-18 FDG PET/CT may be helpful for identifying hepatic involvement in Q fever as a cause of fever of unknown origin.     

A case of secondary hemochromatosis with high uptake of liver in F-18 FDG PET/CT imaging

Hemochromatosis is an iron storage disorder with progressive and massive deposition of iron in the parenchymal cells of various organs. A 72-year-old woman with rheumatoid arthritis diagnosed with secondary hemochromatosis underwent F-18 fluorodeoxyglucose (FDG) positron emission tomography(PET)/computed tomography (CT) to search for malignancy. F-18 FDG PET/CT incidentally showed homogeneous and high FDG uptake (mean SUV, 4.8) in the liver with high density. FDG uptake seemed to be reflected by the functional abnormality of liver. Hemochromatosis should be considered when making a diagnosis of homogeneous high F-18 FDG uptake in liver with high density on CT image.     

Uterine Epithelioid Angiosarcoma on F-18 FDG PET/CT

Uterine epithelioid angiosarcoma can have conventional imaging characteristics similar to those of other uterine tumors, such as leiomyoma, leiomyosarcomas or hemangioendothelioma. Uterine epithelioid angiosarcoma exhibiting increased fluorine-18 fluorodeoxyglucose (F-18 FDG) activity can be misdiagnosed. A 61-year-old woman who was diagnosed with uterine epithelioid angiosarcoma underwent F-18 FDG positron emission tomography/computed tomography (PET/CT) as a part of the pretreatment work up for surgery. F-18 FDG PET/CT showed an intense F-18 FDG uptake in the uterus in addition to increased F-18 FDG uptake at the paraaortic and aortocaval lymph nodes. To our knowledge, this is the first case report of intense F-18 FDG uptake in uterine epithelioid angiosarcoma in Korea.     

Differentiation between malignant and benign pathologic fractures with F-18-fluoro-2-deoxy-<Emphasis Type="SmallCaps">D</Emphasis>-glucose positron emission tomography/computed tomography

Objective To evaluate the efficacy of F-18-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (FDG PET/CT) in differentiating malignant from benign pathologic fractures. Materials and methods F-18 FDG PET/CT was performed on 34 patients with pathologic fractures between May 2004 and June 2007. Fractures were located in tubular bones (26), in the pelvis (six), in the spine (one) and in a rib (one). The FDG uptake pattern at the fracture site was described, whether FDG uptake occurred in the marrow or cortex and soft tissue. Maximum standardized uptake values (SUVmax, the largest value at the region of interest) were measured at the fracture site, including cortical bone, bone marrow and soft tissue. As a reference standard, biopsy was used for 12 patients and clinical follow-up for 22 patients. Sensitivity, specificity and diagnostic accuracy of PET/CT were calculated. Results There were 19 malignant and 15 benign fractures. In the malignant fractures, PET/CT demonstrated high (mean SUVmax 12.0, range 4.3 to 45.7) F-18 FDG uptake in bone marrow in most cases (17 of 19). In benign fractures, there was low FDG uptake (mean SUVmax 2.9, range 0.6 to 5.5) within cortical bone or adjacent soft tissue around the fracture, rarely in the marrow. There were significant differences in the pattern of intramedullary FDG uptake (P < 0.001) and in the mean SUVmax (P < 0.01) between malignant and benign fractures. The sensitivity, specificity and diagnostic accuracy of F-18 FDG PET/CT were 89.5%, 86.7% and 88.2%, respectively, with a cut-off SUVmax set at 4.7. The time interval between fracture and PET/CT did not significantly influence FDG uptake at the fracture site. Conclusion F-18 FDG PET/CT reliably differentiated between malignant and benign fractures based on the SUVmax and based on medullary uptake, which was characteristic for malignant fractures. This research was supported by the Yeungnam University research grants in 2007.     

PET/CT imaging of thyroid cancer

Positron emission tomography (PET) is a highly sensitive, low invasive technology for cancer biology imaging. The role of F-18 FDG PET/CT in differentiated thyroid cancer (DTC) is well established, particularly in patients presenting with elevated Tg levels and negative radioactive iodine WBS. It has been demonstrated that F-18 FDG uptake represents less differentiated thyroid cancer cells or dedifferentiated cells and PET positive lesions are more likely to be resistant to I treatment. The uptake of F-18 FDG is related to tumor size, thyroid capsule invasion and histological variants with a poor prognosis. As in other cancers, early detection of recurrences improves outcomes and survival. I PET/CT can also be used to image the patients with DTC, similarly to I WBS. Compared with F-18 FDG PET/CT, its spatial resolution is only slightly degraded but increasing the imaging time reduces this difference. In addition, F-18 FDG PET/CT has been found helpful in the management of patients with anaplastic and medullary thyroid cancer. Other radiopharmaceuticals such as Ga-DOTATOC and F-18 DOPA may provide complimentary information to F-18 FDG PET/CT in the detection of recurrent thyroid cancer.     

F-18 FDG PET/CT imaging of low-grade mucoepidermoid carcinoma of the bronchus

Mucoepidermoid carcinomas in the bronchial tree are extremely rare tumors. Such tumors are classified into low-grade and high-grade on the basis of histological criteria. Fluorine-18-fluorodeoxyglucose positron emission tomography (F-18 FDG PET) is a useful technique for the evaluation of pulmonary lesions; however, to our knowledge, F-18 FDG PET findings in mucoepidermoid carcinoma of the bronchus have been described in only a few cases. Identifiable focal F-18 FDG uptake has been reported in high-grade mucoepidermoid carcinoma, but it is unclear whether F-18 FDG accumulates in low-grade mucoepidermoid carcinoma. Here, we present the case of a 37-year-old woman, with pathologically proven low-grade mucoepidermoid carcinoma, who underwent high-resolution computed tomography (CT) and F-18 FDG PET/CT before treatment.     

Hypermetabolism of Skeletal Muscles Following Sexual Activity: A Normal Variation

A 46-year-old man with early gastric cancer at the gastric antrum underwent an F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET)-computer tomography (CT) scan for staging. No definite abnormal FDG uptake of the stomach was shown. Incidentally, variable FDG uptake at the bilateral serratus muscles, abdominal muscles and muscles of both thighs (Fig. 1) was observed. He had no significant past medical history except recently diagnosed stomach cancer. On personal interview, he described having had sexual activity the night before the F-18 FDG PET/CT scan, although he was aware of needing to avoid physical activity before a PET scan. The F-18 FDG PET/CT scan was done at 2:00 p.m. Therefore, the hypermetabolism of individual skeletal muscles following sexual activity lasted over 12 h. This case illustrates the hypermetabolism of skeletal muscles following sexual activity as a normal variation.Open in a separate windowFig. 1A 46-year-old man with early gastric cancer at the gastric antrum underwent a F-18 fluorodeoxyglucose (FDG) PET/CT scan for staging. The patient had been fasting for over 6 h, and his blood sugar level was within normal limits at the time of injection. After intravenous injection of 431 MBq F-18 FDG, the patient rested in the supine position for 1 h on a bed. The F-18 FDG PET/CT was acquired 60 min after the injection. The PET/CT scan was done at 2:00 p.m. He had had sexual activity the night before the F-18 FDG PET/CT scan. The MIP image of the F-18 FDG PET (a) shows diffuse and moderate hypermetabolism of the bilateral serratus muscles, bilateral rectus abdominis muscles, left psoas muscle and bilateral adductor muscles. The PET-CT fusion image of the transverse plane (b) and the coronal plane (c) shows diffuse increased uptake of F-18 FDG at bilateral serratus muscles (straight arrows, →, 4.5 and 3.0), bilateral rectus abdominis muscles (arrowheads, ►, 5.5), left psoas muscle (dotted arrow, , 4.0), left iliacus muscle (curved arrow, , 3.3), bilateral pectineus muscles (double arrow heads, , 6.0), bilateral adductor brevis muscles (open arrow, , 5.3) and bilateral adductor longus (solid arrow, , 6.8). The maximum standardized uptake value (SUV) of the individual muscles is in parentheses     

F-18 FDG PET/CT evaluation of radiotherapy response in rare case of mucosa-associated lymphoid tissue lymphoma

We experienced two cases of mucosa-associated lymphoid tissue (MALT) lymphoma arising at unusual locations and used F-18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) to evaluate their response to radiation therapy (RT). A 62-year-old male with proven prostatic MALT lymphoma and a 43-year-old woman with proven duodenal MALT lymphoma had diffuse FDG uptake in the lesion. Both cases were treated with RT; following FDG, PET/CT showed decreased FDG uptake in each lesion. Neither patient had evidence of recurrence at more than 18 months after RT. FDG PET/CT is useful for indicating the treatment site in MALT lymphoma and in evaluation of therapeutic response following RT.     

Incidental thyroid uptake on F-18 FDG PET/CT: correlation with ultrasonography and pathology

Purpose  

To evaluate the usefulness of maximum standard uptake value (max SUV) calculated from F-18 fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) examination and findings from ultrasonographic (US) examination on incidentally detected thyroid FDG uptake on FDG PET/CT.     

Incidental detection of bilateral elastofibroma dorsi with F-18 FDG PET/CT

An 83-year-old asymptomatic woman with a history of breast cancer treated with resection, radiation, and chemotherapy was studied with F-18 FDG positron emission tomography/computed tomography (PET/CT) for staging purposes. The whole-body F-18 FDG PET/CT images revealed poorly circumscribed, bilateral soft tissue masses between the inferior tips of the scapulae and chest wall with a moderate degree of F-18 FDG accumulation. The maximum standardized uptake values were 2.8 for both the left and right lesions. A biopsy or further imaging was not recommended because the lesions were asymptomatic, bilateral, and their imaging features were diagnostic for elastofibroma dorsi. Comparison to a CT scan performed 2 years earlier demonstrated stability of the lesions, further supporting our diagnosis. Recognition of this moderately metabolic benign entity in oncologic patients will avoid unnecessary medical, radiologic, or surgical interventions.     

Hepatic adenomatosis may mimic metastatic lesions of liver with 18F-FDG PET/CT

Hepatic adenomatosis is an uncommon benign neoplasm, with the presence of multiple adenomas (generally more than 4) within the liver. A 52-year-old woman presented with multiple (>10) solid liver lesions detected with abdominal ultrasonography and verified with magnetic resonance imaging (MRI). Subsequently, F-18 FDG PET/CT demonstrated increased uptake in these lesions. Histology revealed hepatic adenomatosis. F-18 FDG PET/CT cannot reliably differentiate hepatic adenomas from malignant processes on the basis of uptake.     

Focal F-18 FDG uptake mimicking malignant gastric localizations disappearing after water ingestion on PET/CT images

Diffuse, increased gastric wall F-18 FDG uptake is widely observed during PET/CT examinations, frequently unrelated to malignant findings, but simply caused by inflammatory disease, physiological emptying, or visceral thickening. Hence, elevated F-18 FDG gastric uptake can lead to equivocal misinterpretation, especially in patients with known gastric malignant disease, at posttherapy reevaluation. Gastric wall contraction can increase F-18 FDG uptake, especially for a remnant stomach, increasing the percentage of false-positive results with a direct impact on therapeutic management. One field PET/CT acquisition centered on the hypochondrial regions a few minutes after water ingestion should be performed routinely if standard images are doubtful (increased tracer uptake and visceral thickening) to differentiate benign from malignant uptake.     

Benign Schwannoma Mimicking Metastatic Lesion on F-18 FDG PET/CT in Differentiated Thyroid Cancer

We report a case of benign schwannoma mimicking metastatic carcinoma. A 55-year-old female with papillary thyroid carcinoma underwent total thyroidectomy. F-18 fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) demonstrated a focal hypermetabolic lesion with maximum standardized uptake value (SUVmax) 5.3 at the right chest wall. Conventional chest CT demonstrated a 5.4 cm ovoid mass lesion between the intercostal muscles and liver. Pathology revealed a schwannoma by tumor excision. This case demonstrates that benign schwannoma may demonstrate FDG uptake mimicking metastatic carcinoma.     

Diagnostic test accuracies of F-18 FDG PET/CT for prediction of microvascular invasion of hepatocellular carcinoma: A meta-analysis

PurposeThe aim of the current meta-analysis was to evaluate diagnostic accuracies of preoperative F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) or positron emission tomography/computed tomography (PET/CT) for prediction of microvascular invasion (MVI) in hepatocellular carcinoma (HCC) patients.MethodsThe scientific database such as PubMed, Cochrane, and Embase database were searched for studies evaluating diagnostic accuracies of preoperative F-18 FDG PET or PET/CT for prediction of MVI in HCC patients up to November 30, 2020.ResultsFourteen eligible studies (1276 patients) were enrolled. The pooled sensitivity for F-18 FDG PET or PET/CT was 0.67 (95% CI; 0.57–0.76) with heterogeneity and a pooled specificity of 0.80 (95% CI; 0.74–0.85) with heterogeneity. Likelihood ratio (LR) syntheses gave an overall positive likelihood ratio (LR+) of 3.3 (95% CI; 2.5–4.5) and negative likelihood ratio (LR−) of 0.41 (95% CI; 0.31–0.55). The pooled diagnostic odds ratio (DOR) was 8 (95% CI; 5–14). Summary receiver operating characteristic (ROC) curve indicates that the area under the curve was 0.81 (95% CI; 0.78–0.84).ConclusionThe current meta-analysis showed a low sensitivity and moderate specificity of F-18 FDG PET or PET/CT for the prediction of MVI in HCC patients. F-18 FDG PET or PET/CT might not be useful for the preoperative prediction of MVI in HCC patients and should not be used to exclude MVI. Therefore, cautious application and interpretation should be paid to the F-18 FDG PET or PET/CT for the prediction of MVI in HCC patients preoperatively.     

Recurrent hepatic epithelioid hemangioendothelioma: detection by FDG PET/CT

A 38-year-old man underwent a resection of the left lobe of the liver resection for a solitary hepatic epithelioid hemangioendothelioma. F-18 fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) was performed for surveillance. This demonstrated 2 foci of FDG uptake in the liver. These were resected and found to represent recurrent epithelioid hemangioendothelioma. Because of the high FDG uptake in this tumor, FDG PET/CT should be evaluated for its utility in recurrence detection.     

Impact of PET/CT in comparison with same day contrast enhanced CT in breast cancer management

PURPOSE: To evaluate the impact of F-18 fluorodeoxyglucose (FDG) positron emission tomography with fused computerized tomography (PET/CT) in comparison with same day contrast enhanced CT (CE-CT) in breast cancer management. METHOD: Seventy studies in 49 breast cancer patients, 17 for initial and 53 for restaging disease were included. All patients underwent PET/CT for diagnostic purposes followed by CE-CT scans of selected body regions. PET/CT was started approximately 90 minutes following IV injection of 10-15 mCi of F-18 FDG on a GE Discovery PET/CT system. Oral contrast was given before F-18 FDG injection. The CE-CT was performed according to departmental protocol. RESULTS: Out of a total of 257 lesions, 210 were concordant between PET/CT and CE-CT. There were 47 discordant lesions, which were verified by either biopsy (35) or follow-up (12 PET positive CE-CT negative lesions). PET/CT correctly identified 25 true positive (TP). CE-CT identified 2 TP lesions missed by PET/CT which were false negatives (FNs): one liver metastasis with necrosis, which was nonavid to FDG uptake because of necrosis and a second one missed on abdominal metastatic node, which did not change staging or treatment. PET/CT incorrectly identified 2 false positive lesions while CE-CT incorrectly identified 18 false positive. TP recurrence of the disease was found by PET/CT in 44% (15/34 pts), whereas 56% (19/34 pts) were free of disease. The CE-CT described progression of the disease in 1 true negative PET/CT study and no progression in 2 TP PET/CT studies. The sensitivity, specificity, accuracy, positive productive value, and negative productive value for PET/CT were 97.8%, 93.5%, 97.3%, 99.1%, 85% and for CE-CT were 87.6%, 42%, 82.1%, 91.6%, 31.7%. CONCLUSION: In this study, PET/CT played a more important role than CE-CT scans alone and provided an impact on the management of breast cancer patients.     

Factors Associated with Diffusely Increased Splenic F-18 FDG Uptake in Patients with Cholangiocarcinoma

Objectives

Although diffuse splenic ¹⁸F-fluorodeoxyglucose (F-18 FDG) uptake exceeding hepatic activity, is considered abnormal, its clinical significance is rarely discussed in the literature. The aim of this study was to determine the contributing factors causing diffusely increased splenic FDG uptake in patients with cholangiocarcinoma.

Methods

From January 2010 to March 2013, 140 patients (84 men, 56 women) were enrolled in this study. All patients had been diagnosed with cholangiocarcinoma and underwent F-18 FDG positron emission tomography/computed tomography (PET/CT) for the pretreatment staging work up. Clinical records were reviewed retrospectively. Various hematological parameters, C-reactive protein (CRP) level, CEA, CA19-9, pancreatic enzymes and liver function tests were conducted within 2 days after the F-18 FDG PET/CT study.

Results

Diffuse splenic uptake was observed in 23 patients (16.4%). Of those, 19 patients (82.6%) underwent endoscopic retrograde cholangiopancreastography (ERCP) 7 days before F-18 FDG PET/CT. The CRP level (p < 0.001) and white blood cell count (p = 0.023) were significantly higher in the group of patients with diffuse splenic FDG uptake. The hemoglobin (p < 0.001) and the hematocrit (p < 0.001) were significantly lower in patients with diffuse splenic FDG uptake. Pancreatic enzymes, liver function test results, and tumor markers were not significantly different between the patients who did or did not have diffusely increased splenic FDG uptake. The significant factors for diffuse splenic F-18 FDG uptake exceeding hepatic F-18 FDG uptake on multivariate analysis included: performing ERCP before F-18 FDG PET-CT (odds ratio [OR], 77.510; 95% CI, 7.624-132.105), and the presence of leukocytosis (OR, 12.436; 95% CI, 2.438-63.445) or anemia (OR, 1.211; 95% CI, 1.051-1.871).

Conclusion

In conclusion, our study demonstrated that concurrent inflammation could be associated with diffusely increased splenic FDG uptake. We suggest that performing ERCP before F-18 FDG PET/CT could cause acute inflammation which may induce splenic FDG activity.     

AFP-producing hepatoid adenocarcinoma of appendix: a case report of 18F-FDG PET/CT

Hepatoid adenocarcinoma (HAC) is a rare tumor. We described here a rare case of appendix HAC. A 59-year-old man underwent F-18-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) for gradually elevated alpha-Fetoprotein level. Multiple masses in the abdominal cavity with moderate FDG uptake were revealed, suggesting malignant tumor with peritoneal metastasis. The patient underwent radical resection, and the postoperative pathological result was HAC originated from the appendix. To our knowledge, it is the first report of HAC of the appendix. Our study suggests that FDG PET/CT may help in detecting the primary tumor and the metastases of HAC.