A functional evaluation of cerebral perfusion for coronary artery bypass grafting patients.

We evaluate the utility of providing a pulsatile blood flow by applying off-pump coronary artery bypass grafting (CABG) or intra-aortic balloon pumping (IABP) with conventional CABG to prevent perioperative stroke in patients with cerebral hypoperfusion on single-photon emission-computed tomography (SPECT). A total of 286 patients underwent isolated CABG with a cerebral magnetic resonance angiography (MRA) evaluation between 2006 and 2015. Seventy-five had significant stenosis and/or occlusion of craniocervical vessels; the other 211 had no significant stenosis. Cerebral SPECT was performed for 49 (SPECT group) of the 75 patients. The SPECT group was further divided into a normal perfusion (NP) (n = 37); and a hypoperfusion (HP) (n = 12). In the present study we compared the NP group and the 211 patients with no significant stenosis (as a control group) to the HP group. No strokes occurred in the HP group, and 1 stroke occurred at the time of operation in the control group. Postoperative stroke within 30 days occurred in 3 patients in the control group; the difference was not statistically significant. The long-term stroke-free rates of the HP and Control group did not differ to a statistically significant extent. The functional evaluation of cerebral perfusion by SPECT is important when patients have significant stenotic lesions on cerebral MRA. Maintaining an adequate pulsatile flow by off-pump CABG or IABP with conventional CABG will help prevent perioperative stroke, even if cerebral hypoperfusion is detected by SPECT.

Human comparative study of zinc and copper excretion via urine after administration of magnetic resonance imaging contrast agents.

PURPOSE: To evaluate the in-vivo pharmacokinetics of magnetic resonance imaging (MRI) contrast agents, the excretion of zinc and copper via urine was studied for three gadolinium (Gd) chelate complexes. MATERIALS AND METHODS: Urine samples were taken before, three hours, and six hours after intravenous administration of Gd-DTPA-BMA, Gd-DTPA, and Gd-DOTA at 0.2 ml/kg to five patients each who underwent contrast-enhanced MRI. Five patients who had non-contrast MRI were evaluated as controls. Urine was assayed for quantitative analysis of zinc and copper using atomic absorption analysis. RESULTS: Gd-DTPA-BMA caused the highest increase in zinc excretion among the three agents, 1,795 +/- 1,273 microg at 3 hours and 985 +/- 434 microg at 3 to 6 hours. Gd-DOTA did not cause a significant increase in zinc excretion, 75 +/- 39 microg at 3 hours and 78+/-65 microg at 3 to 6 hours. Gd-DTPA caused a moderate increase in zinc excretion, 665 +/- 240 microg at 3 hours and 378 +/- 173 microg at 3 to 6 hours. Excretion of copper did not show a significant difference among the three agents. CONCLUSION: Gd-DOTA was found to be the most kinetically inert among the three agents tested. The difference in zinc excretion among the MR contrast agents is possibly related to in-vivo transmetallation of the Gd chelate complexes correlated with variable stability of the contrast agents. The large amount of excess ligands contained in some MR contrast agents was also considered to be responsible for the increase of urinary zinc excretion.

Increased radiation dose by automatic exposure control system during fluoroscopy and angiography of pelvis due to contrast material in the bladder: experimental study.

PURPOSE: To evaluate the increase of radiation dose caused by contrast material excreted in the bladder during vascular interventional procedures of the pelvis. MATERIALS AND METHODS: A latex balloon filled with diluted contrast material, simulating the bladder, was placed in a water phantom. Entrance dose rates were measured under various conditions with and without the balloon. In animal experiments, skin doses during fluoroscopy and angiographic image acquisitions were measured at the pelvis of a swine before and after the contrast was excreted in the bladder. RESULTS: In phantom experiments, fluoroscopic dose rates increased 1.3- to 3.9-fold when the contrast-filled balloon was placed at the periphery of the phantom. The dose rates increased 3.0- to 4.0-fold when the balloon was placed at the center. In the animal experiment, dose rates increased 1.4- to 2.0-fold when the bladder was filled with contrast material. Skin doses during 10-second angiographic image acquisition also increased 1.1- to 2.3-fold when the bladder was filled with contrast. CONCLUSION: When the bladder is filled with excreted contrast material, skin doses delivered by fluoroscopy and angiography will increase. Removal of urine is recommended during vascular interventional procedures of the pelvis.

Oblique approach for CT-guided liver radiofrequency ablation using multiplanar reformation images in hepatocellular carcinoma.

PURPOSE: To evaluate the feasibility and safety of CT-guided radiofrequency (RF) ablation by caudal-cranial oblique insertion using multiplanar reformation (MPR) images for hepatocellular carcinomas (HCCs). MATERIALS AND METHODS: Twenty-two HCCs in 19 patients that were difficult to demonstrate on ultrasound (mean tumor diameter was 17.5 mm) were treated with CT-guided RF ablation by caudal-cranial oblique insertion to avoid pneumothorax, using MPR images after transcatheter arterial chemoembolization. The insertion point and direction of insertion, avoiding aerated lung parenchyma, bones, large vessels, and intestine, were sought on the MPR images. Technical success was defined as complete eradication of tumor enhancement in the contrast-enhanced CT. Local tumor progression was defined by the appearance of enhanced tumor adjacent to the zone of ablation. The technical success rate, local tumor progression, and complications were investigated. RESULTS: The coronal plane was used for insertion in 18 tumors, the sagittal plane in 3 tumors, and the oblique plane in 1 tumor. RF electrode placement was successful and complete necrosis was obtained in all cases. During the mean follow-up period of 38.0 months, local tumor progression was not detected in any of the patients. There were no major complications, including pneumothorax. CONCLUSION: CT-guided RF ablation by caudal-cranial oblique insertion using MPR images is a feasible and safe therapeutic option.

Emergent coil embolization for ruptured renal artery aneurysm.

We report a case of ruptured renal artery aneurysm successfully treated by emergent transcatheter embolization with microcoils. A 66-year-old woman was referred for emergency treatment after presenting with sudden-onset left flank pain and vomiting. Blood examination showed anemia. Computed tomography demonstrated a partly calcified mass with massive retroperitoneal hematoma. With the diagnosis of a ruptured left renal artery aneurysm, emergency angiography was performed. Left renal arteriography demonstrated a saccular aneurysm at the lower aspect of the renal hilum. A total of five microcoils were placed at the arterial branch, including the orifice of the aneurysm. The first coil was partly lodged in a branch near the orifice of the aneurysm that was used as an "anchor" to prevent subsequent coils from migrating and effectively occluding the parent artery with a short segment. Two branches originating from the renal hilum were preserved. The postoperative course was favorable. Endovascular treatments, including coil embolization, appear to be effective, safe, and less invasive than surgery. This method should be considered as a treatment of choice for ruptured renal artery aneurysm.

Angiographic guidewire with measuring markers: design and clinical experience.

PURPOSE: We have developed an angiographic guidewire with measuring markers to determine accurately how far a guidewire is inserted within a catheter. We investigated whether use of this guidewire reduces the risk of vascular injury and the fluoroscopic time during guidewire manipulations. METHODS: Four markers were put on the surface of the guidewire at 80, 100, 110, and 120 cm from the tip. The actual lengths of 54 catheters from seven manufacturers were measured and compared with the nominal lengths. Sixty consecutive patients who underwent angiography were randomized into two groups: in one group guidewires with surface markers were used (marker group) and in the other group, conventional guidewires (control group). For each guidewire insertion, the fluoroscopic time before the guidewire was pushed forward into the vessel lumen was recorded. The number of occasions on which unintentionally the guidewire had already been pushed out of the catheter at the start of fluoroscopy was also evaluated. RESULTS: The actual lengths of all catheters were greater than the nominal lengths by 1.0-11.0 cm. Mean fluoroscopic time for each guidewire insertion was 3.3 sec in the marker group and 5.7 sec in the control group (p < 0.05). Guidewires were unintentionally pushed out of the catheters without fluoroscopy three times (3.6%), in each case in the control group. CONCLUSION: The guidewire with measuring markers is effective for enhancing safety and in reducing fluoroscopic radiation during angiographic procedures. It is recommended that operators be aware that actual lengths of catheters may vary significantly from the nominal lengths listed; they should be aware of this with any guidewire, but particularly with the angiographic measuring guidewire.