Does CEA and CA 19-9 combined increase the likelihood of 18F-FDG in detecting recurrence in colorectal patients with negative CeCT?

AIM: The purpose of this prospective study was to investigate the role of 2-(fluorine-18)-fluoro-2-deoxy-D-glucose ((18)F-FDG) PET/computed tomography (CT) in the diagnosis of recurrent colorectal cancer (CRC) in patients with increased tumor markers and negative contrast-enhanced computed tomography (CeCT) results. MATERIAL AND METHODS: Forty-three patients (27 male; median age 66 years, range 31-93 years) with increasing tumor markers and negative CeCT during follow-up for treated CRC underwent (18)F-FDG PET/CT examinations. The serum values of carcinoembryonic antigen (CEA) (n=29) and CA 19-9 (n=20) were normal after completion of treatment, with subsequent increasing concentrations. RESULTS: Among the 43 patients, (18)F-FDG PET/CT was true positive in 32 (74.4%), false positive in two (4.7%), false negative in one (2.3%), and true negative in eight (1%) patients. On the patient-basis analysis, (18)F-FDG PET/CT had a sensitivity of 97% (confidence interval: 0.82-0.99), a specificity of 80% (0.44-0.96), a positive predictive value of 94% (0.78-0.98), and a negative predictive value of 88% (0.5-0.99). There was no statistically significant correlation between CRC recurrence and CEA and CA19-9 levels (P=0.561 and 0.55, respectively). Only in the group of patients (n=6) with both tumor markers increased did (18)F-FDG PET/CT have 100% accuracy in revealing recurrent disease. CONCLUSION: (18)F-FDG PET/CT is highly sensitive in the diagnosis of recurrent CRC in patients with increasing levels of tumor markers and negative CeCT regardless of the type or level of tumor marker; however, the combination of elevated CEA and CA 19-9 increases the likelihood of (18)F-FDG in detecting recurrence.

Contrast enhanced ultrasound of the kidneys: what is it capable of?

One of the many imaging uses of contrast enhanced ultrasound (CEUS) is studying a wide variety of kidney pathology, due to its ability to detect microvascular blood flow in real time without affecting renal function. CEUS enables dynamic assessment and quantification of microvascularisation up to capillary perfusion. The objective of this paper is to briefly refresh basic knowledge of ultrasound (US) contrast agents' physical properties, to study technical details of CEUS scanning in the kidneys, and to review the commonest renal indications for CEUS, with imaging examples in comparison to baseline unenhanced US and computed tomography when performed. Safety matters and limitations of CEUS of the kidneys are also discussed.

Correlation between Calcitonin Levels and [(18)F]FDG-PET/CT in the Detection of Recurrence in Patients with Sporadic and Hereditary Medullary Thyroid Cancer.

Purpose. Measurement of serum calcitonin is important in the followup of patients with medullary thyroid carcinoma (MTC) and reliably reflects the presence of the disease. This is the largest study so far in bibliography investigating the diagnostic accuracy of combined [(18)F]FDG-PET/CT in patients with MTC and elevated calcitonin levels. Methods. Between February 2007 and February 2011, 59 [(18)F]FDG-PET/CT were performed on 51 patients with MTC and elevated calcitonin levels for localization of recurrent disease. Conventional morphologic imaging methods were negative or showed equivocal findings. Results. Among the 59 [(18)F]FDG-PET/CT, 29 were positive (26 had true-positive and 3 false-positive findings) and 30 negative. The overall per-patient sensitivity of [(18)F]FDG-PET/CT was 44.1%. Using as cut-off point the calcitonin value of 1000 pg/ml, in patients with calcitonin exceeding this value, sensitivity raised to 86.7%. The overall sensitivity of [(18)F]FDG-PET/CT was lower (23%) in patients with MEN IIA syndrome. Conclusion. The findings of this paper show that [(18)F]FDG-PET/CT is valuable for the detection of recurrence in patients with highly elevated calcitonin levels, >1000 pg/mL, but in patients with lower calcitonin levels, its contribution is questionable. Also, there is evidence that the sensitivity of [(18)F]FDG-PET/CT is lower in patients with MTC as part of MEN IIA syndrome.

High incidence of peritoneal implants in recurrence of intra-abdominal cancer revealed by 18F-FDG PET/CT in patients with increased tumor markers and negative findings on conventional imaging.

OBJECTIVE: The aim of this prospective study was to investigate the role of 18F-fluorodeoxyglucose (18F-FDG) PET/CT in the diagnosis of recurrent intra-abdominal cancer in patients with increased tumor markers and negative findings on conventional imaging studies. METHODS: Seventy-three patients (30 men; age 61.1 ± 11.5 years) with intra-abdominal cancer (colorectal, n=32; ovarian, n=18; gastric, n=7; pancreatic, n=7; cervical, n=4; endometrial, n=3; duodenal, n=1; and small bowel, n=1) and increasing levels of tumor markers during follow-up and negative CT, MRI or both underwent 125 18F-FDG PET/CT examinations. The final diagnosis was confirmed by histopathological findings in 22 patients, clinical follow-up (median of 12 months) in 13 patients,and repeated imaging with 18F-FDG PET/CT examinations in 38 patients. RESULTS: Of 73 cancer patients, 18F-FDG PET/CT identified recurrent disease in 52 patients and ruled out in 21 patients. 18F-FDG PET/CT scan was true positive (TP) in 49 patients, false positive in three patients, false negative in four patients, and true negative in 17 patients. In our study, the 18F-FDG-PET/CT scan had a sensitivity of 92.4%, a specificity of 85%, and an accuracy of 91%. Fourteen of 49 TP studies (28.5%) showed peritoneal implants only. Moreover, peritoneal implants were detected in additional nine of 49 TP studies (18.3%) presented with multiple lesions. Thus, half of the true-positive examination revealed peritoneal implants that CT or MRI had not depicted. CONCLUSION: The results of this study indicate a high incidence of peritoneal implants revealed by 18F-FDG PET/CT in the diagnosis of recurrent intra-abdominal cancer in patients with increasing tumor markers and negative findings on conventional imaging studies.

A case of fever of unknown origin: (18)F-FDG-PET/CT findings in Takayasu's arteritis.

This is a case of a 54 years old woman with fever of unknown origin. Physical examination showed nothing remarkable. Chest radiographs, abdominal ultrasound examination (US) and chest-abdominal-pelvic CT, showed segmental thickening of the wall of the aorta. On admission, the C-reactive protein level and the erythrocyte sedimentation rate were elevated. (18)Fluoro-fluorodeoxyglucose-positron emission tomography ((18)F-FDG-PET/CT) showed increased uptake of the aorta wall and its main branches that could be indicative of arteritis. The temporal artery biopsy was negative for giant-cell arteritis. The patient responded well to prednisolone treatment. A second (18)F-FDG-PET/CT scan showed great improvement. (18)F-FDG-PET/CT scan early indicates arteritis of the great vessels that in this case was considered to be TA and contributes in monitoring disease activity.

Imaging of the mediastinum: applications for thoracic surgery.

The diagnostic approach to patients who have mediastinal masses should include thorough preoperative imaging. Once limited to plain radiographic techniques, the radiologist now has a wide variety of imaging modalities to aid in the evaluation of the mediastinum. CT is the imaging modality of choice for evaluating a suspected mediastinal mass or a widened mediastinum, and it provides the most useful information for the diagnosis, treatment, and evaluation of postoperative complications.