Validation and initial application of a semiautomatic aneurysm measurement software: a tool for assessing volumetric packing attenuation.

BACKGROUND AND PURPOSE: Precise aneurysm measurements and volume embolization ratios are essential for long-term durability of endovascular coil embolization. We evaluated the accuracy of newly developed semiautomatic cerebral aneurysm measurement software, NeuroVision, and explored the value of volume embolization ratio in the prediction of re-treatment. MATERIALS AND METHODS: We compared software-derived volume measurements of 4 silicone aneurysm models with those calculated with an approximation formula and ground truth values (validation study). We used NeuroVision to retrospectively evaluate outcomes of 100 unruptured aneurysms (97 patients) treated with embolization (clinical study). Aneurysm size (height, width, and neck), volume, and volume embolization ratios were calculated for 3 groups (stable, recanalization, and re-treatment) and were compared. RESULTS: This validation study illustrated higher accuracy of NeuroVision in computing aneurysm volume compared with an approximation formula: percentage absolute errors were 4.50% ± 3.18% and 23.07% ± 17.60%, with maximal percentage absolute errors of 8.99% and 45.63%, respectively. Of 100 unruptured aneurysms, 20 recanalized and 12 were re-treated. Average volume embolization ratios of stable and re-treated aneurysms were 24.88% ± 5.91% and 20.50% ± 4.06%, respectively (P ≤ .01). The optimal volume embolization ratio cutoff point for re-treatment was < 19.15%, at which the Youden index was 0.50 (sensitivity, 58.33%; specificity, 87.50%; area under the receiver operating characteristic curve, 0.74). CONCLUSIONS: The NeuroVision software provided accurate aneurysm volume measurements and may be a useful standardized tool to measure aneurysm size and volume, especially for multicenter clinical studies. Volume embolization ratio may be a valuable predictor of aneurysm occlusion changes.

Justification of unruptured intracranial aneurysm repair: a single-center experience.

BACKGROUND AND PURPOSE: Whether to treat UIAs is controversial. The aim of the study was to compare the clinical outcome of patients with UIAs who were either treated conservatively or preventively. MATERIALS AND METHODS: Patients with UIAs referred to our institution were prospectively enrolled in the study. Data collected included baseline characteristics, aneurysmal features, and procedural and follow-up information. Preventive treatment was recommended if the aneurysm was larger than 5 mm and was considered safely treatable. Endovascular surgery was the first-line therapy if the aneurysmal shape was appropriate for coiling. RESULTS: From January 2003 through April 2008, a total of 879 patients with 1110 UIAs were enrolled; 325 patients with 369 UIAs (mean size, 7.8 mm) were treated (treatment group), and 603 patients with 741 UIAs (mean size, 4.4 mm) were managed conservatively (observation group). Mean follow-up was 692.5 days (1405.5 person-years). In the observation group, 26 aneurysms (3.5%) had ruptured (1.8% per year; 1405.5 person-years), 10 patients died, and 7 were disabled (mRS, 3-6: 2.8%). Aneurysmal size was a significant risk factor for rupture (P = .001). The treatment group included aneurysms treated either with coiling (n=315), clipping (n=32), or a combined approach (n=9); 1 patient died, and 3 were disabled (mRS, 3-6: 1.2%). Therapeutic intervention was equal (UIAs of all sizes) or superior (UIAs > 5 mm; P = .025) to conservative management. CONCLUSIONS: Treatment of UIAs was justified in aneurysms larger than 5 mm, and EVS can be safely applied to nearly 90% of UIAs.

Radiation Exposure during Cerebral Artery Aneurysm Coil Embolization: the Current Situation and Measures to Prevent Radiation Injury.

SUMMARY: Coil embolization is the treatment of choice for cerebral artery aneurysms at our institution. The duration of a fluoroscopic study and frequency of radiation exposure are varied, and the safety measures against radiation injury have not yet been established. Guidelines about radiation injury prevention with IVR have been published. However, there is not yet a detailed report for the head region. We also report our measures to try to reduce the amount of radiation exposure during the embolization procedure in our institution.

Efficacy of 3-D Reconstructed Time of Flight MRA Follow-up of the Embolized Cerebral Aneurysms.

SUMMARY: A follow-up of the embolized cerebral aneurysm with Guglielmi Detachable Coils (GDC) were performed mainly using craniograms and digital subtraction angiograms (DSA) so far.Recently, several authors have reported about efficacy of the time of flight (TOF) magnetic resonance angiogram (MRA) as a follow-up for the embolized cerebral aneurysms. In our institution, 3-D reconstructed TOF MRAs have been performed as a follow-up of the embolized cerebral aneurysms.We examined efficacy of 3-D reconstructed TOF MRA. 3-D TOF MRA was performed for a followup of the embolized cerebral aneurysms at our outpatient clinic in 35 patients. Morphological examination of the 3-D images between 3-D TOF MRA and 3-D DSA was performed. Almost similar images of 3-D MRA were obtained after 3-D reconstruction as compared with those of 3-D DSA. In three cases, recanalization was suspected in the 3-D TOF MRA. And recanalization was confirmed in the 3-D DSA actually. A quality of 3-D TOF MRA for a diagnosis of recanalization was good and practical. However, in two cases, arteries were partially disappeared in the 3-D TOF MRA.These were the artifact due to coil mass and this is a current limitation of 3-D TOF MRA. The images of 3-D TOF MRA that were reconstructed in the 3-D workstation were very similar to those of 3-D DSA. 3-D reconstructed TOF MRA was very useful for a less-invasive diagnosis of a recanalization of the embolized cerebral aneurysms.

Thromboembolic Events during Endovascular Coil Embolization of Cerebral Aneurysms.

SUMMARY: Thromboembolic events was most important adverse event for coil embolization for intracerebral aneurysm. The present study investigated possible risk factors for thromboembolic events during coil embolization using diffusion-weighted imaging (DWI), comparing unruptured and ruptured lesions.

Endovascular treatment of experimental cerebral aneurysms using thermoreversible liquid embolic agents.

SUMMARY: We have developed a new embolic agent, thermoreversible gelation polymer (TGP). This polymer is unique in that solidification occurs at body temperature. The utility of this new liquid embolic agent for the treatment of large experimental aneurysms was evaluated angiographically. TGP remains liquid at temperatures below the sol-gel transition temperature (TT) and becomes gelatinous above the TT. TGP can also be used to slowly deliver biologically active substances such as growth factors or engineered cells. In this study, TGP was mixed with radiopaque material without solvent. Bilateral common carotid arteries of swine (n=5) were used for surgical creation of lateral aneurysms, then 1 aneurysm in each animal was embolized using TGP without any protection device. The remaining untreated aneurysm in each animal was used as a control. All aneurysms were successfully embolized using TGP. No distal migration of TGP was observed when aneurysms were embolized without using protection devices. TGP can be safely used to embolize experimental aneurysms. Embolization of aneurysms with a protection device needs to be evaluated. Further modifications such as mechanical stability and use as a drug delivery system will be necessary prior to the clinical application of TGP.

Balloon Test Occlusion with Perfusion CT Imaging Utilizing Intraarterial Contrast Injection.

SUMMARY: Balloon Test Occlusion (BTO) is performed to evaluate the collateral flow when a permanent therapeutic occlusion of unilateral carotid artery is planned. BTO with neurological evaluation alone, however, has a rather high false negative rate. In order to improve the sensitivity, several adjunctive procedures such as induced hypotension or cerebral blood flow (CBF) measurement with various modalities have been combined. Perfusion CT (PCT) is another imaging modality that is mainly used for the diagnosis of acute stroke. In this study, we evaluate the efficacy and the safety of BTO combined with PCT in the same procedure utilizing intraarterial contrast injection from the catheter. Seven patients underwent BTO with PCT in our institution. All the procedures were performed in the angio/CT combination suite. BTO was performed in the usual fashion and when the patient passed the 30 minutes' BTO clinically, PCT was performed subsequently. Contrast material was injected from a Pig Tail catheter placed in the ascending aorta. The obtained data were transferred to a workstation and perfusion maps of CBF, cerebral blood volume (CBV), and time to peak (TTP) were generated using software. In three patients, single photon emission CT (SPECT) was also obtained with administering 99 mTc-ethyl cysteinate dimer (99 mTc-ECD) intravenously during BTO. Although all the patients had passed the BTO clinically, the CBF maps of three patients revealed significant decrease in the occluded hemisphere. There was no procedure-related morbidity. PCT using intraarterial contrast injection during BTO was performed successfully and safely. Intraarterial injection allowed us to obtain excellent time-attenuation curves by utilizing less contrast material and less radiation doze.

Preoperative radio/chemo-radiotherapy in combination with intraoperative radiotherapy for T3-4Nx rectal cancer.

AIMS: To analyse the results of a single institution experience of combined preoperative radio/chemo-radiotherapy and intraoperative electron-radiation therapy (IORT) for locally advanced rectal cancer and to compare the results with surgery alone retrospectively. METHODS: The study cohort comprised 99 patients with clinical T3-4NxM0 adenocarcinoma of the rectum who had received preoperative radio/chemo-radiotherapy, radical surgery, and IORT [Group I]. Until 1998, 67 patients were treated with radiation only [Group Ia], and after 1999, 32 patients were concurrently given tegafur and uracil (UFT) [Group Ib]. 68 patients with clinical T3-4NxM0 rectal cancer were treated with surgery alone [Group II]. RESULTS: The median follow-up was 67 months in Group I and 83 months in Group II. Local recurrence rate was 2% in Group I, which was significantly lower than 16% in Group II (p=0.002) Both disease-free survival and overall survival in Group I were significantly better than those in Group II (p=0.04, p=0.02, respectively). Sphincter preservation was possible in 78% in Group Ib, which was significantly more than 42% in Group Ia (p=0.002). CONCLUSIONS: The combined preoperative radio/chemo-radiotherapy and IORT for clinical T3-4Nx rectal cancer significantly reduces local recurrence and improves prognosis. Combination of preoperative radiotherapy and oral UFT improves the feasibility of sphincter-preservation.

A simple objective parameter for perfusion study of renal transplant.

We proposed a simple parameter, the kidney-to-aorta ratio (KAR), for evaluation of renal transplant perfusion. KAR was calculated from the peak counts of the kidney and the aorta. The calculated values were compared with the visual interpretation of the radionuclide first-pass flow study, percent renal uptake (%RU), and tubular extraction rate (TER) by Bubeck's one point sampling method in 37 studies. KAR correlated well with the visual interpretation of the flow study and the other quantitative parameters. Representative cases, which showed the usefulness of KAR for the objective assessment of the perfusion status of renal transplants, were presented. In conclusion, KAR is a simple and practically useful parameter for objective evaluation and follow-up of renal transplant perfusion.

[Prediction of the clinical efficacy of hepatic arterial chemotherapy for metastatic hepatic cancer by intraarterial infusion of 99mTc-MIBI].

SPECT was performed in 11 patients with metastatic hepatic cancer by intraarterial infusion of 99mTc-MIBI before hepatic arterial chemotherapy was started, and the degree of accumulation and clinical efficacy were compared. Early and delayed SPECT images were obtained and various parameters were calculated, including early ratio (ER), delayed ratio (DR), washout rate (WR), and retention index (RI). Judgement of clinical efficacy was made by CT before and after hepatic arterial chemotherapy and was classified as effective, unchanged, and progressive groups. The mean values of ER and DR in the effective group were higher than those in the progressive group. No relationships were noted among the WR and RI values of the groups. The assessment of ER and DR using 99mTc-MIBI intraarterial SPECT is considered to be useful for prediction of the clinical efficacy of hepatic arterial chemotherapy for metastatic hepatic cancer.

[Application of measuring 99mTc-MAG3 plasma clearance based on one-compartment model (MPC method) to renal transplantation].

Measurement of 99mTc-MAG3 plasma clearance (CLmag) based on one-compartment model (MPC method) was applied to renal transplantation and evaluated for the factors which might affect the calculated results, especially concerning renal depth. Correlation coefficient of CLmag between MPC method using real renal depth and Russell or Bubeck single sampling method was good (r = 0.852 or 0.876, respectively). Regression equation between MPC method and Russell method was y = 1.044x - 3.0 and was more closer to y = x than that between MPC method and Bubeck method. CLmag of MPC method calculated by estimated renal depth from the abdominal thickness was also similar to that by real renal depth. Even if the fixed renal depth, 4 cm, was applied, the coefficient and regression equation between MPC method and Russell method were r = 0.884 and y = 1.004x - 10.2. In conclusion, MPC method is applicable to the evaluation of renal transplants. Though measuring renal depth is best, calculation with fixed renal depth of 4 cm might be practically acceptable.

Infected subdural hematoma.

A case is presented in which Escherichia coli seeded a pre-existing chronic subdural hematoma. A 77-year-old woman was admitted to our hospital because of lethargy, left hemiparesis and fever. Drainage through a burr hole was performed with the diagnosis of bilateral chronic subdural hematoma. Operative findings revealed the infected subdural hematoma on the right side and non-infected subdural hematoma on the left side. Cultures of the subdural hematoma grew Escherichia coli. In view of the pyuria, the etiology of the infected subdural hematoma was postulated to be a urinary tract infection. In the majority of 14 reported cases, the causative organisms were Escherichia coli, Salmonella, and the systemic sources of infection included the urinary tract, gastrointestinal disease, or were unknown. The possibility of infected subdural hematoma should be considered when computed tomography findings suggestive of chronic subdural hematoma exist in a patient with signs of infection.