Reduction of patient radiation dose with a new organ based dose modulation technique for thoraco-abdominopelvic computed tomography (CT) (Liver dose right index).

PURPOSE: To evaluate the radiation dose reduction, image quality and diagnostic confidence with thoraco-abdominopelvic computed tomography (TACT) using a new organ based dose modulation system (liver dose right index [Liver DRI]), compared to TACT using a standard automatic exposure control adjusting mA according to attenuation. METHODS: A total of 37 patients who had two TACT examinations on 2 different CT scanners, one using standard automatic exposure control (combination of a DoseRight automatic current selection and Z modulation) and one using Liver DRI were included. There were 19 men and 18 women with a mean age of 67.6±11.7 (SD) years (range: 36-85 years) For each patient, volume CT dose index (CTDIvol), size-specific dose estimates (SSDE) and signal-to-noise ratio (SNR) were evaluated at each anatomic level (lung, breast, liver and pelvis area) for each protocol. Two radiologists assessed independently image quality, artifacts and diagnostic confidence. RESULTS: The radiation dose decreased significantly using Liver DRI compared to standard automatic exposure control on the total scan length, lung, breast and pelvis area, with a significant CTDIvol reduction of 27% (P=0.0001), 23% (P=0.0002), 24% (P=0.0002) and 31% (P=0.0001), respectively; and a significant SSDE reduction of 23% (P=0.0001), 28% (P=0.0001), 23% (P=0.0002) and 29% (P=0.0001), respectively. No significant SNR reductions were observed in all measured tissues at the level of the aortic arch, celiac trunk and iliac bifurcation, except in the muscle (P=0.0013) and fat tissue (P=0.0052) at the level of the ureteral meatus. No significant differences were noted between both protocols in overall image quality, artifacts and diagnostic confidence with an excellent inter observer agreement between radiologists (Kappa values of 0.83, 0.85 and 0.88, respectively). CONCLUSION: Liver DRI organ based dose modulation technique allows significant dose reduction compared to standard automatic exposure control while preserving diagnostic image quality in all thoraco-abdominopelvic areas.

Rituximab induces resolution of recurrent diffuse alveolar hemorrhage in a patient with primary antiphospholipid antibody syndrome.

Diffuse alveolar hemorrhage (DAH) is a rare manifestation of primary antiphospholipid antibody syndrome (APS). We describe a patient with primary APS and refractory recurrent episodes of DAH. The patient was admitted 15 times due to recurrent episodes of DAH in a period of 18 months. Multiple immunosuppressive drugs did not improve his condition. Two years after his presentation, he was treated with rituximab (two doses of 1 g, 2 weeks apart). Six months later, the attacks of DAH have gradually disappeared. In a follow-up of more than 2 years after he received rituximab, the patient has had no further admissions due to DAH. Levels of antiphospholipid antibodies were measured during follow-up of 4 years. Anti-ß2 glycoprotein IgG titer decreased to normal 6 months after therapy but anticardiolipin (aCL) antibody titer increased. We conclude that rituximab caused a dramatic clinical response in this patient. Anti-ß2 glycoprotein IgG correlated better with the clinical response in this patient than aCL.

CT-integrated robot for interventional procedures: preliminary experiment and computer-human interfaces.

Pre-operative planning and intra-operative computer interfaces for minimally invasive interventions were investigated with an active robot integrated with a CT scanner. To test the robotic system, a biopsy study was performed using a pig. For pre-operative planning, a virtual needle was superimposed on axial slices and multiplanar reformatted views in correlation with the interventional field. The path of the virtual needle was sent to the robot's controller, and the robot's needle gripper moved into a position congruent with the planned path. Intra-operative controls were then used to drive the needle while keeping the interventionalist's hands out of the direct X-ray beam during CT fluoroscopy. After needle insertion, the imaged and virtual needles were shown to be sufficiently congruent.