Kyoung Sook Won

Peritoneal carcinomatosis in patients with ovarian cancer: Enhanced CT versus 18F-FDG PET/CT

Purpose The study aimed to evaluate the efficacy of PET/CT in detecting peritoneal carcinomatosis in patients with ovarian cancer and to compare the diagnostic accuracy of FDG PET/CT with that of enhanced abdominal CT. Methods The medical records of 46 consecutive patients with ovarian cancer were reviewed, and the presence of peritoneal tumor on 18F-FDG PET/CT and enhanced abdominal CT scans was also assessed. Imaging results were compared with the pathologic findings obtained by surgery. Results Pathologic results were positive for peritoneal carcinomatosis in 26 patients and negative in 20 patients. PET/CT correctly detected 25 of 26 patients with peritoneal carcinomatosis and enhanced abdominal CT correctly detected 23 of 26 patients. Sensitivity and specificity for the diagnosis of peritoneal carcinomatosis were 96.2% and 90%, respectively, for PET/CT and 88.5% and 65%, respectively, for enhanced abdominal CT. The accuracy of PET/CT was statistically higher than that of enhanced abdominal CT (93.5% vs 78.3%, P = 0.039). Four distinctly abnormal PET/CT findings of single nodular, multiple nodular, diffuse, and mixed FDG uptakes were identified and corresponded to pathologic findings. Conclusions 18F-FDG PET/CT imaging is efficient in the diagnosis of peritoneal carcinomatosis and its performance is superior to that of enhanced abdominal CT.

Preoperative Standardized Uptake Value of Metastatic Lymph Nodes Measured by 18F-FDG PET/CT Improves the Prediction of Prognosis in Gastric Cancer

AbstractThis study assessed whether preoperative maximum standardized uptake value (SUVmax) of metastatic lymph nodes (LNs) measured by 18F-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (18F-FDG PET/CT) could improve the prediction of prognosis in gastric cancer.One hundred fifty-one patients with gastric cancer and pathologically confirmed LN involvement who had undergone preoperative 18F-FDG PET/CT prior to curative surgical resection were retrospectively enrolled. To obtain nodal SUVmax, a transaxial image representing the highest 18F-FDG uptake was carefully selected, and a region of interest was manually drawn on the highest 18F-FDG accumulating LN. Conventional prognostic parameters and PET findings (primary tumor and nodal SUVmax) were analyzed for prediction of recurrence-free survival (RFS) and overall survival (OS). Furthermore, prognostic accuracy of survival models was assessed using c-statistics.Of the 151 patients, 38 (25%) experienced recurrence and 34 (23%) died during follow-up (median follow-up, 48 months; range, 5–74 months). Twenty-seven patients (18%) showed positive 18F-FDG nodal uptake (range, 2.0–22.6). In these 27 patients, a receiver-operating characteristic curve demonstrated a nodal SUVmax of 2.8 to be the optimal cutoff for predicting RFS and OS. The univariate and multivariate analyses showed that nodal SUVmax (hazard ratio [HR] = 2.71, P < 0.0001), pathologic N (pN) stage (HR = 2.58, P = 0.0058), and pathologic T (pT) stage (HR = 1.77, P = 0.0191) were independent prognostic factors for RFS. Also, nodal SUVmax (HR = 2.80, P < 0.0001) and pN stage (HR = 2.28, P = 0.0222) were independent prognostic factors for OS. A predictive survival model incorporating conventional risk factors (pT/pN stage) gave a c-statistic of 0.833 for RFS and 0.827 for OS, whereas a model combination of nodal SUVmax with pT/pN stage gave a c-statistic of 0.871 for RFS (P = 0.0355) and 0.877 for OS (P = 0.0313).Nodal SUVmax measured by preoperative 18F-FDG PET/CT is an independent prognostic factor for RFS and OS. Combining nodal SUVmax with pT/pN staging can improve survival prediction precision in patients with gastric cancer.

Diagnosis of orbital cavernous hemangioma with Tc-99m RBC SPECT.

The authors report two cases of orbital cavernous hemangioma diagnosed by Tc-99m RBC SPECT. Tc-99m RBC SPECT showed a typical scintigraphic pattern commonly seen in hepatic hemangioma in which there is intense focally increased uptake on delayed SPECT images. Tc-99m RBC SPECT in orbital cavernous hemangioma may be as useful a diagnostic modality as in hepatic hemangioma.

The impact of DaTscan in the diagnosis of Parkinson disease.

Purpose The aim of this study was to evaluate the impact of DaTscan in a heterogeneous group of patients with movement disorders as well as the degree of confidence in scan findings between different readers. Procedures A retrospective evaluation of consecutive patients who underwent DaTscan during 1 year was performed. The patients’ demographics, symptoms, duration, clinical diagnosis, and medications were collected. The scan findings were categorized by 2 blinded observers on a semiquantitative scale as follows: 0, normal; 1, mild; 2, moderate; 3, marked; and 4, absent uptake for each of the caudate heads and putamina separately. A correlation of the scan findings with the clinical symptoms and diagnosis as well as interobserver agreement was performed. Disagreement was considered when a difference greater than 2 in more than 1 area of the basal ganglia was recorded. Descriptive statistics and &kgr; test for interobserver agreement were used for data analysis. Results Fifty-seven patients were included (mean age, 63.4 years; 29 men, 28 women). Clinical diagnosis of Parkinson disease (PD) was certain in 26 and uncertain in 31 patients. DaTscan was markedly abnormal in 24 (92%) of 26 patients with certain clinical diagnosis of PD and normal in the remaining 2 (8%). In 31 patients with uncertain diagnosis, 15 (48%) had markedly abnormal scans, 5 (16%) had mild abnormalities, and 11 (36%) had normal scans. Each of the sensitivity and positive predictive value of DaTscan in patients who had certain clinical diagnosis of PD (26 patients) is 92%. Interobserver agreement occurred in 52 (91%) of 57 scans and disagreement in 5 (9%) of 57 (&kgr; = 0.82). There was also a good correlation with laterality of symptoms in 32 (82%) of 39 positive studies. Conclusions Markedly abnormal DaTscan is confirmed as the diagnostic pattern for PD. This pattern helps confirm the diagnosis in patients with unclear clinical diagnosis. Good interobserver agreement is easily obtained in reading DaTscans.

Cervical tuberculous lymphadenitis mimicking distant lymph node metastasis on F-18 FDG PET/CT in a patient with gastric carcinoid tumor.

A 35-year-old man was diagnosed with gastric carcinoid tumor and underwent whole body F-18 FDG PET/CT for staging. F-18 FDG PET/CT showed no abnormal uptake in the stomach. However, there was increased uptake in the right cervical lymph nodes. An open biopsy of the lymph node confirmed tuberculous lymphadenitis without malignancy. The increased uptake of cervical lymph nodes on F-18 FDG PET/CT imaging should be interpreted with caution in differentiating benign from malignant lesions and should be confirmed by pathologic examination before the initiation of a definitive treatment.

Simultaneous splenic and colonic metastases from gastric cancer: different FDG avidities according to the density of cancer cells imaged on FDG PET/CT.

We describe the ¹⁸F-FDG PET/CT findings of 2 simultaneous metastatic gastric cancers to the colon and spleen with quite different FDG avidities. Longitudinal and weak FDG uptake was observed in the descending colon; therefore, it could not be distinguished from nonpathological functional uptake of normal colon. Meanwhile, the splenic mass showed intense uptake. Contrast-enhanced CT revealed a segmental wall thickening of the descending colon as well as a hypoattenuating splenic mass suggesting metastases. Splenectomy and left hemicolectomy were performed. Histological diagnosis disclosed metastatic gastric cancer. The differential diagnoses and review of the literature are presented.

Extraosseous bone tracer accumulation of the liver on 99mTc-HDP bone scintigraphy in intermittent bleeding after iatrogenic liver injury.

A 69-year-old man with common bile duct cancer and deep jaundice had complained of abdominal pain after percutaneous transhepatic biliary drainage. The laboratory workup showed reduction of serum hemoglobin level after the procedure. A 99mTc-hydroxy diphosphonate bone scan was performed for further evaluation of common bile duct cancer, and there was no abnormality of the skeletal structures. However, diffuse and hazy increased radiotracer uptake was detected on the liver. Follow-up contrast-enhanced 99mCT revealed hematoma and subcapsular hemorrhage of the liver.

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.

Diagnostic accuracy of 18F-FDG PET/CT for detecting synchronous advanced colorectal neoplasia in patients with gastric cancer.

AbstractPreoperative screening for synchronous colorectal neoplasia (CRN) has been recommended in patients with gastric cancer because patients with gastric cancer are at increased risk for synchronous CRN. The aim of this study was to investigate the diagnostic accuracy of 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) for detecting synchronous advanced CRN in patients with gastric cancer.A total of 256 patients who underwent colonoscopy and 18F-FDG PET/CT for preoperative staging were enrolled in this study. The diagnosis of focal colonic 18F-FDG uptake on 18F-FDG PET/CT image was made based on histopathologic results from the colonoscopic biopsy. The 18F-FDG PET/CT result was considered as true positive for advanced CRN when focal 18F-FDG uptake matched colorectal carcinoma or adenoma with high-grade dysplasia in the same location on colonoscopy.Synchronous advanced CRN was detected in 21 of the 256 patients (4.7%). Sensitivity, specificity, and accuracy of 18F-FDG PET/CT were 76.2%, 96.2%, and 94.5%. The size of CRN with a true positive result was significantly larger than that with a false negative result.18F-FDG PET/CT demonstrated high diagnostic accuracy for detecting synchronous advanced CRN in patients with gastric cancer. Colonoscopy is recommended as the next diagnostic step for further evaluation of a positive 18F-FDG PET/CT result in patients with gastric cancer.

Colon Visualization on 99mTc-HDP Whole-Body Bone Scan Due to Sigmoid Colon Cancer-Related Enterovesical Fistula

An abnormally increased uptake of the bone-seeking agent is rarely observed in structures other than the bone and urinary track on bone scintigraphy. The general etiologies of soft tissue uptake can be explained by heterotopic ossification or dystrophic and metastatic calcification. We report a case of serendipitous visualization of the entire colon on bone scintigraphy. Diffuse colonic uptake was detected on the whole-body bone scan in a patient with biopsy-proven sigmoid colon cancer. Additional imaging studies clearly showed direct bladder invasion of the sigmoid colon cancer. Imaging findings with a brief review of the literature are presented in this article.