Three-phase 18F-fluorocholine PET/CT in the evaluation of prostate cancer recurrence.

AIM: Contribution of 3-phase 18F-fluorocholine PET/CT in suspected prostate cancer recurrence at early rise of PSA. PATIENTS, METHODS: Retrospective analysis was performed in 47 patients after initial treatment with radiotherapy (n=30) or surgery (n=17). Following CT, 10 minutes list-mode PET acquisition was done over the prostate bed after injection of 300 MBq of 18F-fluorocholine. Three timeframes of 3 minutes each were reconstructed for analysis. All patients underwent subsequent whole body PET/CT. Delayed pelvic PET/CT was obtained in 36 patients. PET/CT was interpreted visually by two observers and SUVmax determined for suspicious lesions. Biopsies were obtained from 13 patients. RESULTS: Biopsies confirmed the presence of cancer in 11 of 13 patients with positive PET for a total of 15 local recurrences in which average SUVmax increased during 14 minutes post injection and marginally decreased in delayed scanning. Conversely inguinal lymph nodes with mild to moderate metabolic activity on PET showed a clearly different pattern with decreasing SUVmax on dynamic images. Three-phase PET/CT contributed to the diagnostic assessment of 10 of 47 patients with biological evidence of recurrence of cancer. It notably allowed the discrimination of confounding blood pool or urinary activity from suspicious hyperactivities. PET/CT was positive in all patients with PSA>or=2 ng/ml (n=34) and in 4/13 patients presenting PSA values<2 ng/ml. CONCLUSION: 18F-fluorocholine 3-phase PET/CT showed a progressively increasing SUVmax in biopsy confirmed cancer lesions up to 14 minutes post injection while decreasing in inguinal lymph nodes interpreted as benign. Furthermore, it was very useful in differentiating local recurrences from confounding blood pool and urinary activity.

Pooling of echographic contrast agents during transcranial Doppler sonography: a sign in favor of slow-flowing giant saccular aneurysms.

Transcranial Doppler (TCD) sonography is a new imaging technique allowing for non-invasive evaluation of the intracranial vascular anatomy and cerebral hemodynamics. The recent introduction of echographic contrast agents has significantly increased the sensitivity of TCD for the diagnosis of intracranial vascular lesions. We report a case of giant AComA aneurysm, undetected by color and power TCD, which became visible after echographic contrast administration as a delayed and persistent area of contrast enhancement. Knowledge of atypical or contrast-specific lesion appearances will become important if contrast-enhanced TCD is to be used routinely in the diagnosis of intracranial aneurysms.

Absolute renal blood flow quantification by dynamic MRI and Gd-DTPA.

The aim of this study was to demonstrate the feasibility of the absolute renal blood flow quantification using MRI and injection of contrast media. Using a T1-weighted fast gradient sequence following an intravenous bolus injection of Gd-DTPA, dynamic images of the kidney were obtained in patients with well-functioning native kidneys (n = 7) or transplant (n = 9), with significant renal artery stenosis (n = 4) and with renal failure (n = 7). After signal intensity calibration, the absolute renal perfusion was equal to the wash-in slope of the renal transit curve divided by the contrast medium concentration at the peak of the bolus in the aorta. The cortical blood flow was 2.54+/-1.16 ml/min per gram in well-functioning kidneys decreasing to 1.09+/-0.75 ml/min per gram in case of renal artery stenosis (p = 0.04) and to 0.51+/-0.34 ml/min per gram in case of renal failure (P<0.001). These measurements were in agreement with previous results obtained by other methods. A standard MRI imaging sequence and a simple model can provide realistic quantitative data on renal perfusion. This work justifies further studies to compare this model with a gold standard for renal blood flow measurements.

The effect of contrast material on transcranial Doppler evaluation of normal middle cerebral artery peak systolic velocity.

BACKGROUND AND PURPOSE: Several recent studies have shown that sonographic contrast agents may affect transcranial Doppler evaluation of the arterial peak systolic velocity (PSV). Some investigators reported an increase in PSV, and others reported no change in PSV compared with baseline values. This study was conducted to determine the effect of sonographic contrast agent on PSV measured in normal middle cerebral arteries. METHODS: Continuous spectral Doppler sonography was performed on the right middle cerebral artery of 20 participants with angiographically proven normal intracranial vasculature. Videotaping was performed in each case from the initiation of the administration of contrast medium until the effect of the contrast agent on the PSV subsided. The PSV values were normalized for each participant, were pooled, and were plotted as a function of time. RESULTS: PSV increased in all participants after the administration of contrast material; the mean maximum increase was 24+/-7.4% (mean +/- standard deviation) (range, 15-36%). The mean duration of PSV increase was 320+/-97 s (range, 165-465 s). CONCLUSION: The middle cerebral artery PSV increased substantially after the administration of contrast material. This effect needs to be considered if velocity thresholds developed for disease detection without the use of contrast materials are used when contrast agents are administered.

Twinkling artifact on intracerebral color Doppler sonography.

Transcranial Doppler sonography shows potential as a noninvasive technique for long-term follow-up of treated intracranial saccular aneurysms. This technical note describes a color Doppler artifact related to microcoil architecture that might represent a potential pitfall in transcranial Doppler sonographic evaluation of aneurysmal cavity thrombosis, since it may be wrongly interpreted as residual flow or aneurysmal cavity recanalization.

[Intrathoracic dislocation fracture of the head of the humerus]. / Fracture-luxation intrathoracique de la tête humérale.

We present a rare case of fracture-dislocation of shoulder with intrathoracic displacement of the humeral head. This case is well documented by CT. The mechanism and treatment modalities are discussed, and pertinent literature is reviewed.

Retroperitoneal bleeding after L4-L5 diskectomy in a patient with crossed-fused renal ectopia: treatment by selective embolization.

We present a complication of L4-L5 disk surgery and its treatment by interventional radiology which has not previously been reported. An accessory inferior polar artery of a crossed-fused renal ectopia was injured and the bleeding was successfully managed by selective embolization.