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.     

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.     

Abdominal Mesh Implant Showing FDG Uptake on PET/CT

F-18 fluorodeoxyglucose (FDG) uptake by a mesh implant might be caused by a foreign body granulomatous reaction with inflammation and fibrosis, which can be demonstrated by positron emission tomography/computed tomography (PET/CT). A 71-year-old man underwent F-18 FDG PET/CT for the follow-up evaluation after an operation for colonic adenocarcinoma. On PET/CT imaging, there was a rectangular-shaped FDG uptake (maximal standardized uptake value, maxSUV: 3.4) in the anterior abdominal wall. On the review of the medical records, the patient had a history of herniorrhapy for the reinforcement of the abdominal wall 2 months previously, using a mesh implant consisting of polytetrafluoroethylene (Teflon). We report a case of FDG uptake associated with surgical procedures including mesh implant on F-18 FDG PET/CT.     

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.     

Positron emission tomography/computed tomography fusion imaging in brown adipose tissue

Fluorine-18 fluoro deoxyglucose positron emission tomography (F-18 FDG PET) imaging is an exciting modality for the study of pathophysiology. The fusion of computed tomography (CT) anatomic data to metabolic F-18 FDG PET data allows accurate mapping of the metabolic activity of the body. With each patient evaluated with fusion PET/CT imaging, valuable information is obtained regarding anatomic and physiological abnormalities and normal variants. We describe 4 cases in which the unusual distribution of increased FDG metabolism localized to fat, which we propose represents brown adipose tissue. The accurate anatomic localization of this hypermetabolic fat is aided by imaging these patients on a combined PET/CT system.     

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.     

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.     

Incidental Detection of Peri-Renal Hemorrhage on F-18 FDG PET/CT Imaging in a Patient with Polycystic Kidney Disease

A 72-year-old male patient with a history of polycystic kidney disease and lung malignancy underwent F-18 fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) for the evaluation of tumor recurrence. The FDG PET/CT and subsequent non-enhanced CT scans revealed a hemorrhage in the peri-renal space of the left original kidney. Interesting in this case was the incidental detection of unexpected peri-renal hemorrhage during an oncologic assessment with FDG PET/CT.     

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 Urethral Metastasis from Sigmoid Colon Cancer Diagnostically and Prognostically Indicated by F-18 FDG PET/CT

Urethral metastasis from colorectal cancer is rare and is known to have a poor prognosis. A 72-year-old man with a history of colectomy and colostomy due to sigmoid colon cancer was admitted to the emergency room with bowel distension, rectal bleeding and urinary symptoms. Computed tomography of the abdominopelvis showed sigmoid colon cancer with multiple metastases involving the liver. Positron emission tomography with F-18 fluorodeoxyglucose (FDG) showed multiple hypermetabolic foci in the liver, penis and pubic bone, which otherwise could not be diagnosed. The lesions revealed no improvement with chemotherapy and urological surgery on follow-up F-18 FDG PET/CT. We present a case of urethral metastasis of sigmoid colon cancer diagnostically and prognostically indicated by F-18 FDG PET/CT.     

Role of F-18 FDG PET/CT in assessing bone marrow involvement in pediatric Hodgkin’s lymphoma

Objectives

The aim of the current study was to assess the utility of F-18-fluoro-2-deoxy-d-glucose (F-18 FDG) positron emission tomography/computed tomography (PET/CT) in assessing bone marrow involvement (BMI) compared to bone marrow biopsy (BMB) in initial staging of Hodgkin’s lymphoma (HL) in pediatric patients.

Methods

Data of 38 pediatric patients (mean age 9.8 years, range 3–18 years) with HL were analyzed for the involvement of bone marrow. All patients underwent non-contrast F-18 FDG PET/CT study. BMB was done in 31 patients from the bilateral iliac crests. Scans were interpreted by two nuclear medicine physicians blinded to the details of BMB.

Results

Of the 31 patients who underwent BMB, 5 patients had lymphomatous involvement on BMB. PET/CT was positive in four of these five patients. In 26 patients negative on BMB, PET was negative in 23 patients and positive in 3 patients for BMI. The sensitivity and negative predictive value of F-18 FDG PET/CT was 87.5 and 96 %, respectively, for BMI.

Conclusions

F-18 FDG PET/CT can predict BMB results with high accuracy. F-18 FDG PET/CT may be used at initial staging of pediatric Hodgkin’s lymphoma as it uncovers unsuspected BMI and BMB may be omitted in patients with PET-positive BMI.     

Detection of Thyroid Metastasis of Renal Transitional Cell Carcinoma Using FDG PET/CT

A 69-year-old man who was diagnosed with renal transitional cell carcinoma (TCC) underwent F-18 fluorodeoxyglucose (FDG) positron emission tomography with computed tomography (PET/CT) for detecting recurrence after chemotherapy. FDG PET/CT revealed multiple new hypermetabolic lesions in many places, including the right thyroid gland. Biopsy of the thyroid lesion was performed, and a diagnosis of metastatic TCC was made. We could detect thyroid metastasis of renal TCC by FDG PET/CT.     

Unexpected Second Primary Malignancies Detected by F-18 FDG PET/CT During Follow-up for Primary Malignancy: Two Case Reports

As the survival rate of cancer patients has increased over the last few decades, the risk of cancer survivors developing second primary malignancies has gained attention. We report two rare cases of second primary hematologic malignancy detected by ¹⁸F-fluorodeoxyglucose (F-18 FDG) positron emission tomography/computed tomography (PET/CT) during follow-up for primary solid malignancies. Acute lymphoblastic leukemia developed in a breast cancer patient and non-Hodgkin lymphoma in an anal cancer patient. F-18 FDG PET/CT findings led to the diagnosis of unexpected second primary hematologic malignancy in cancer survivors in these two cases.     

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.     

Monitoring Therapeutic Response in a Case of Extrapulmonary Tuberculosis by Serial F-18 FDG PET/CT

Due to the low yield of AFB smear and culture in extrapulmonary tuberculosis, therapeutic responses of patients with extrapulmonary tuberculosis are usually monitored clinically and/or radiographically. Such monitoring techniques, however, are not enough to provide effective diagnosis if a remnant lesion exists after treatment. Tuberculosis presents hypermetabolic activity on F-18 fluorodeoxyglucose positron emission tomography/computed tomography (F-18 FDG PET/CT) scanning. Reported herein is a case of extrapulmonary tuberculosis where the therapeutic response was assessed via serial F-18 FDG PET/CT scanning, which was useful for detecting the extent of extrapulmonary tuberculosis and for estimating the patient’s therapeutic response.     

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.     

Noninvasive and invasive staging of ovarian cancer: review of the literature

The use of F-18 FDG PET/CT in the characterization of doubtful adnexal findings and in the staging of ovarian cancer is being extensively evaluated. The purpose of our article is to review the literature and to add our experience to the published works. We concluded that F-18 FDG PET/CT could represent an important method in addition to other imaging modalities (transvaginal ultrasound-, and contrast-enhanced computed tomography) in the characterization of adnexal masses and in the staging of ovarian cancer patients, particularly in assessing the presence of extra-abdominal metastatic spread.     

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.     

Peritoneal tuberculosis with elevated serum CA125 mimicking peritoneal carcinomatosis on F-18 FDG-PET/CT

18F-fluorodeoxyglucose positron emission tomography (F-18 FDG-PET) plays an important role in differentiating benign from malignant tumors. However, some false-positive findings, such as tuberculosis, may occur. We report a case referred for F-18 FDG whole-body PET computed tomography (PET/CT) scan owing to an elevated serum cancer antigen 125 (CA125). An FDG-PET/CT scan showed multiple hypermetabolic foci in the mesentery and peritoneum with further increase of FDG uptake on the delayed scan, mimicking peritoneal carcinomatosis. Subsequent laparoscopic biopsy showed granulomatous inflammation, and tuberculosis polymerase chain reaction showed a positive result. Serum CA125 returned to normal following treatment with anti-tuberculosis drugs. Peritoneal tuberculosis should be considered as a differential diagnosis in a tuberculosis endemic region.     

Cerebral Toxoplasmosis in a Patient with AIDS on F-18 FDG PET/CT

The distinction between primary central nervous system (CNS) lymphoma and nonmalignant lesions due to opportunistic infections, in particular cerebral toxoplasmosis, is important because of the different treatments involved. A 32-year-old patient with AIDS was hospitalized for intermittent headaches. Brain magnetic resonance imaging (MRI) showed a small well-enhanced nodular lesion in the right frontal lobe. A fluorine-18 fluorodeoxyglucose (F-18 FDG) positron emission tomography (PET)/computed tomography (CT) scan showed moderate FDG uptake in the nodular lesion of the right frontal lobe. We present a case of cerebral toxoplasmosis in a patient with acquired immunodeficiency syndrome (AIDS) and the usefulness of F-18 FDG PET/CT in the differential diagnosis of the cerebral toxoplasmosis will be discussed.