Half Fourier single-shot turbo spin-echo magnetic resonance urography for the evaluation of suspected renal colic in pregnancy.

OBJECTIVE: To report our experience with magnetic resonance urography (MRU) in pregnant women suspected of having obstructing upper tract calculi. The diagnosis of an upper tract calculus in the pregnant woman can be challenging. Recent evidence suggests that MRU can be used to effectively evaluate renal colic. METHODS: From 2008-2011, 9 pregnant women were referred for evaluation of suspected renal colic caused by an obstructing upper tract stone. All patients underwent MRU with a half Fourier single-shot turbo spin-echo (HASTE) protocol. Medical records and imaging studies were reviewed for demographic and clinical data as well as outcome measures. RESULTS: The mean age of the subjects was 25 years (range 20-34); average gestational age of the fetus was 23 weeks (range 9-36). In all cases, a renal ultrasound was the initial imaging study obtained, with nondiagnostic findings. HASTE MRU detected 4 ureteral stones and 4 cases of physiological hydronephrosis of pregnancy. In one case, interpretation of the MRU was limited as a result of patient motion. Of the patients with obstructing stones, 1 required endourologic management during her pregnancy and 3 were followed conservatively. No adverse events related to MRU occurred. CONCLUSION: HASTE MRU is an informative imaging study for pregnant women with suspected upper tract stone disease. Information gathered from this study augments that gained from alternative modalities, and aids in medical decision-making. The lack of ionizing radiation exposure, coupled with the capture of detailed anatomic imaging, makes HASTE MRU a particularly useful study in this setting.

Robotically driven interventions: a method of using CT fluoroscopy without radiation exposure to the physician.

Radiation exposure to physicians' hands during interventional procedures with computed tomography (CT) fluoroscopic guidance may be high. A robot was developed that could hold, orient, and advance a needle, with CT fluoroscopic guidance. This robot could be either computer or joystick controlled. Twenty-three robotically guided percutaneous interventions were performed without complication. Physician radiation exposure was negligible during the CT fluoroscopy-guided procedures.

Percutaneous gadolinium injection under MR guidance to mark target for CT-guided radiofrequency ablation.

Selection of the appropriate imaging tool depends on a number of factors that reflect the patient, the procedure, and the physician. Multiple imaging techniques are often required to perform elements of a whole procedure. A patient with an allergy to iodinated contrast material and a 3.0-cm hepatic metastasis that was invisible on computed tomography (CT) was treated with CT-guided radiofrequency ablation by first injecting gadolinium under magnetic resonance guidance to mark the location of the lesion. Gadolinium's high atomic number makes it a viable contrast agent for attenuating x rays under fluoroscopic or CT guidance.