Super Early Scan of PSMA PET/CT in Evaluating Primary and Metastatic Lesions of Prostate Cancer.

68Ga-prostate specific membrane antigen (PSMA)-11 PET/CT has been widely used in the diagnosis of prostate cancer (PCa); however, the urine lead shielding resulting from the urinary metabolism of tracers may obstruct the detection of surrounding metastasis. In this research, the additive value of super early scanning in diagnosing primary lesions and metastasis in the pelvic cavity was evaluated. Firstly, the differentiation efficiency of 68Ga-PSMA-11 PET scanned at 3 min post-injection (min P.I.) was measured in PSMA-positive (22rv1 cells) and PSMA-negative (PC3 cells) model mice. Secondly, 106 patients were scanned at 3 min P.I. for the pelvic cavity and then scanned as a standard protocol at 45 min P.I. In the results, the differential diagnosis of PSMA expression was completely reflected as early as 3 min P.I. for mice models. For patients, when correlated with the Gleason score, the quantitative results of the super early scan displayed a comparable correlation coefficient with the routine scan. The target to bladder ratios increased from 1.44 ± 2.40 at 45 min to 10.10 ± 19.10 at 3 min (p < 0.001) for the primary lesions, and it increased from 0.99 ± 1.88 to 9.27 ± 23.03 for metastasis. Meanwhile, the target to background ratios increased from 2.21 ± 2.44 at 3 min to 19.13 ± 23.93 at 45 min (p < 0.001) for the primary lesions, and it increased from 1.68 ± 2.71 to 12.04 ± 18.73 (p < 0.001) for metastasis. In conclusion, super early scanning of 68Ga-PSMA-11 PET/CT added referable information for metastasis detection in order to avoid disturbing tracer activity in the urinary system.

A retrospective study of 23 cases with subacute combined degeneration.

PURPOSE: To study retrospectively the diverse presentations, ancillary tests and neuroimaging in patients with subacute combined degeneration (SCD). METHODS: Twenty-three Chinese patients with SCD were included in this study. The clinical presentations and laboratory data including comprehensive metabolic panel, serum folic acid, vitamin B12 levels, gastroscopy and images of spinal cord on magnetic resonance imaging (MRI) were evaluated. Rating scales for localizations of lesions and functional disabilities were used to define the severity of neurological impairment. RESULTS: No difference was found between men and women in the age of disease onset. For most of the patients, sensory symptoms, oftentimes as initial symptoms, occurred earlier than motor symptoms. The signs of the disease were more obvious than the symptoms. Six patients had sensory deficit levels mimicking transverse myelopathy. Anemia was not always detected in our patients with SCD. Normal or even elevated serum levels of vitamin B12 were found in seven patients. Spinal cord lesions on MRI were observed in six patients and the clinical and neuroimaging findings were not necessarily consistent. CONCLUSIONS: The sensory symptoms occur earlier than the motor symptoms in SCD patients. SCD patients may have sensory deficit level. Normal or even elevated serum levels of vitamin B12 may occur in patients with SCD.

(18)F-FDG PET/CT of adrenal lesions.

OBJECTIVE: The purpose of this review is to describe FDG uptake characteristics of adrenal lesions, which can show increased FDG uptake on PET/CT. CONCLUSION: Both benign and malignant adrenal lesions can show increased FDG uptake. Knowledge of the uptake characteristics of these lesions is helpful for increasing diagnostic accuracy and expanding the differential diagnosis for adrenal lesions.

Spectrum of the prostate lesions with increased FDG uptake on (18)F-FDG PET/CT.

OBJECTIVE: Increased FDG uptake in the prostate can be caused by both benign and malignant conditions. The purpose of this pictorial review is to demonstrate a spectrum of prostate lesions which can show increased FDG uptake on PET/CT imaging. CONCLUSION: Various prostate lesions can show increased FDG uptake. Knowledge of the uptake characteristics of these lesions may be helpful for increasing diagnostic accuracy.

Patterns of FDG uptake in pancreatic non-Hodgkin's lymphoma lesions.

PURPOSE: The aim of this study was to evaluate the pattern of FDG uptake in pancreatic non-Hodgkin's lymphoma (NHL) lesions. METHODS: The study included 9 consecutive patients with newly diagnosed NHL with pancreatic involvement who underwent an F-18 fluorodeoxyglucose positron emission tomography/computed tomography (F-18 FDG PET/CT) scan. The location, size, maximal standardized uptake value (SUVmax), and FDG uptake patterns of the pancreatic lesions were reviewed. RESULTS: Four different patterns of FDG uptake could be distinguished in the affected pancreas corresponding to different types of lymphoma lesions. These included focal FDG uptake by distinct solitary lesions (5 patients), multiple foci of FDG uptake corresponding to separate lymphoma lesions (1 patient), segmental FDG uptake caused by lymphoma infiltration limited to a pancreatic segment (1 patient), and diffuse FDG uptake related to diffuse lymphomatous infiltration of the entire pancreas (2 patients). All types of lesions showed increased metabolic activity with maximal standardized uptake values (SUVmax) ranging from 7.4 to 26.5. On CT images, the segmental and diffuse patterns of FDG uptake correlated to segmental and diffuse pancreatic enlargement accordingly. All lesions showed isodensity or slight hypodensity in relation to pancreatic tissue. The pancreatic head was the most frequent site of involvement (8/9). Mildly dilated pancreatic duct was noted only in 2 patients. CONCLUSIONS: The described patterns of FDG uptake and correlative CT findings may be helpful for a better characterization of NHL involving the pancreas and for differential diagnosis with other lesions, including pancreatic adenocarcinomas.

FDG PET/CT in Solitary Isolated Renal Metastasis From Squamous Cell Lung Cancer.

ABSTRACT: We describe FDG PET/CT findings in a patient with a solitary isolated renal metastasis from squamous cell lung cancer. The renal metastasis appeared as a small focus of activity at the renal cortex on FDG PET/CT at initial staging of the lung tumor, misinterpreted as cortical tracer retention, and was significantly enlarged on the second FDG PET/CT performed 4 months after the first PET/CT. This case demonstrates the usefulness of FDG PET/CT in identifying unexpected extrathoracic metastasis from lung cancer. Focal FDG uptake in the renal cortical region in a cancer patient should be evaluated carefully to avoid misdiagnosis.

Intense FDG Uptake in Leiomyomatosis Peritonealis Disseminata With Fumarate Hydratase Deficiency.

ABSTRACT: A 35-year-old woman with a history of laparoscopic myomectomy presented with repeated abdominal pain. Contrast-enhanced abdominal and pelvic CT showed multiple enhancing solid or mixed cystic and solid peritoneal masses, and an enhancing uterine mass. All these masses showed intense FDG uptake on FDG PET/CT. The intraperitoneal and uterine masses were surgically removed. The histological and immunohistochemical findings of the peritoneal lesions were consistent with leiomyomatosis peritonealis disseminata with fumarate hydratase deficiency, and the uterine mass was adenomyosis. This case indicates fumarate hydratase-deficient extrauterine leiomyoma can show intense FDG uptake mimicking malignancy.

FDG PET/CT in a Case of Isolated Gastric Metastasis From Pancreatic Ductal Adenocarcinoma.

ABSTRACT: Hematogenous gastric metastasis from pancreatic cancer is extremely rare. We describe FDG PET/CT findings in a case of isolated hematogenous gastric metastasis from pancreatic cancer with significantly elevated serum carbohydrate antigen 19-9 level. The gastric metastasis showed intense focal FDG uptake mimicking a primary tumor. The elevation of serum carbohydrate antigen 19-9 level may be useful as an aid in the differential diagnosis.

FDG PET/CT in Pancreatic Ductal Adenocarcinoma Arising From a Heterotopic Pancreas of the Pylorus.

ABSTRACT: Malignant transformation of heterotopic pancreas is extremely rare. We describe FDG PET/CT findings in a case of pancreatic ductal adenocarcinoma arising from a heterotopic pancreas in the submucosa of the pylorus with peripyloric lymph node metastasis and elevated serum carbohydrate antigen 19-9 level. The heterotopic pancreatic adenocarcinoma showed intense FDG uptake, and the peripyloric lymph node metastasis showed mild FDG uptake. This case indicates that heterotopic pancreatic adenocarcinoma should be included in the differential diagnosis of FDG-avid gastric submucosal lesions, especially in patients with elevated serum carbohydrate antigen 19-9 level.

FDG PET/CT in Staging and Response Evaluation of Primary Urothelial Carcinoma of the Urethra.

ABSTRACT: Primary urethral urothelial carcinoma is a rare aggressive tumor with a high propensity for local invasion and regional and distal metastases. We describe the usefulness of FDG PET/CT in management of a patient with primary urethral urothelial carcinoma. FDG PET/CT at initial staging showed FDG-avid primary tumor and lymph node metastasis of the left groin, and mild or no activity of the lung metastases due to small size. FDG PET/CT after 4 cycles of chemotherapy showed progression of the primary tumor and lung metastases, partial response of the left inguinal lymphadenopathy, and multiple new sites of FDG-avid metastases.

Diffuse Intense 18 F-PSMA-1007 Uptake of the Breasts in a Woman With TFE3-Rearranged Renal Cell Carcinoma.

ABSTRACT: A 23-year-old woman presenting with gross hematuria was found to have a left renal mass suspicious for renal cell carcinoma on abdominal contrast-enhanced CT. An 18 F-PSMA-1007 PET/CT scan was performed for evaluating the renal mass. 18 F-PSMA-1007 PET/CT showed focal activity of the renal mass, which was a transcription factor E3-rearranged renal cell carcinoma proved after nephrectomy. Surprisingly, diffuse heterogeneous intense activity of the bilateral breasts and moderate activity of the right accessory breast was observed. There was no morphological abnormality of the bilateral breasts and right accessory breast on CT images, indicating physiological PSMA uptake.

Intraureteral Metastasis From Colon Cancer Mimicking Primary Ureteral Carcinoma on FDG PET/CT.

ABSTRACT: Hematogenous or lymphatic intraureteral metastasis from distant primary cancer is very rare. We present contrast-enhanced CT and FDG PET/CT findings in a case of intraureteral metastasis from colonic adenocarcinoma 3 years after colectomy. The intraureteral showed moderate enhancement on contrast-enhanced CT and increased FDG uptake on PET/CT mimicking a primary ureteral carcinoma. This case suggests that metastatic tumor of the ureter should be considered in the differential diagnosis in patients with hypermetabolic ureteral lesion and known malignancy.

FDG PET/CT Findings of Primary Pulmonary Choriocarcinoma in a Postmenopausal Woman.

ABSTRACT: Choriocarcinomas usually occur in the genital tracts of reproductive-age women after a gestational event. Primary pulmonary choriocarcinoma is very rare. We describe FDG PET/CT findings of primary pulmonary choriocarcinoma with multiple intrapulmonary metastases in a postmenopausal woman with elevated serum beta human chorionic gonadotropin level. On FDG PET/CT, the large primary lung tumor showed intense FDG uptake (SUV max , 46), and the small intrapulmonary metastases showed variable FDG uptake (SUV max , 27). Primary pulmonary choriocarcinoma should be included in the differential diagnosis of FDG-avid pulmonary lesions with elevated serum beta human chorionic gonadotropin levels, including metastatic choriocarcinoma and lung cancer.

FDG PET/CT in a Case of Solitary Mixed Squamous Cell and Glandular Papilloma of the Lung With High CEA Level.

ABSTRACT: Solitary mixed squamous cell and glandular papilloma of the lung is an extremely rare benign neoplasm. We describe FDG PET/CT findings in a case of solitary mixed squamous cell and glandular papilloma of the lung with high serum carcinoembryonic antigen level (63.3 ng/mL; reference, <5 ng/mL). The tumor showed intense FDG uptake with SUVmax of 23.8 mimicking lung cancer.

Intense 18 F-PSMA-1007 Uptake of Splenic Hemangioma.

ABSTRACT: A 77-year-old man was referred for 18 F-PSMA-1007 PET/CT scan for initial staging of biopsy-proved prostate adenocarcinoma. 18 F-PSMA-1007 PET/CT showed focal intense 18 F-PSMA-1007 of the prostate adenocarcinoma and a focal intense activity (SUV max , 27) in the spleen. The 18 F-PSMA-1007-avid splenic lesion corresponded to a splenic hemangioma, which was initially detected on contrast-enhanced CT 7 months ago and unchanged in size and enhancement pattern on follow-up contrast-enhanced CT. This case indicates that splenic hemangioma should be included in the differential diagnosis of PSMA-avid splenic lesions.

Hemangioma of the Ilium Simulating Bone Metastasis on 18 F-PSMA-1007 PET/CT.

ABSTRACT: A 64-year-old man was referred for 18 F-PSMA-1007 PET/CT scan for initial staging of biopsy-proved prostate adenocarcinoma. 18 F-PSMA-1007 PET/CT showed focal intense 18 F-PSMA-1007 of the prostate adenocarcinoma and a focal intense activity with SUV max of 10.5 in the left ilium. The 18 F-PSMA-1007-avid iliac bone lesion corresponded to a hemangioma, which was initially detected on pelvic MRI 13 months ago and remained stable in size. This case indicates that hemangioma should be included in the differential diagnosis of PSMA-avid iliac bone lesions.

Atypical Bone Involvement in Erdheim-Chester Disease Showing No or Subtle Structure Changes and Increased Activity on FDG PET/CT.

ABSTRACT: Bones are the most common sites involved in Erdheim-Chester disease. On imaging, the bone involvement in Erdheim-Chester disease typically presents as osteosclerotic lesions, and osteolytic lesions are unusual. Bone lesions showing no or subtle structure changes are rarely reported. We describe FDG PET/CT findings in a case of Erdheim-Chester disease with atypical bone involvement. The bone lesions showed no or subtle structure changes without obvious osteosclerosis or osteolysis on radiographs and CT, and increased FDG activity mimicking lymphoma. Familiarity with these atypical imaging findings of bone involvement in Erdheim-Chester disease is helpful for the diagnosis.

Intense FDG Uptake in Well-Differentiated Inflammatory Liposarcoma of the Retroperitoneum.

ABSTRACT: Inflammatory variant of well-differentiated liposarcoma is a rare subtype of liposarcoma, and its imaging features have been rarely reported. We describe FDG PET/CT findings in a case of well-differentiated inflammatory liposarcoma. The tumor showed no detectable fat and intense FDG uptake and caused diffuse FDG uptake of the bone marrow due to paraneoplastic leukemoid reaction. Microscopically, there were extensive inflammatory infiltrates in the tumor, which may contribute to the intense FDG uptake. This case indicates that although well-differentiated liposarcoma usually shows low-grade FDG uptake, inflammatory variant of well-differentiated liposarcoma can show intense FDG uptake mimicking high-grade liposarcoma.