Katsuhide Ito

Prospective versus Retrospective ECG-gated 64-Detector Coronary CT Angiography: Assessment of Image Quality, Stenosis, and Radiation Dose

PURPOSE To show that prospective electrocardiographically (ECG)-triggered coronary computed tomographic (CT) angiography (hereafter, prospective CT angiography) is at least as effective as retrospective ECG-gated coronary CT angiography (hereafter, retrospective CT angiography). MATERIALS AND METHODS Institutional review committee approval and informed consent were obtained. Sixty patients with heart rates of less than 75 beats per minute who were referred for coronary CT angiography were enrolled. Both prospective and retrospective CT angiography were performed with a 64-detector scanner. Data acquisition times were recorded. Two independent cardiac radiologists evaluated subjective image quality (1, excellent; 4, poor) and severity of stenosis (0% occlusion, 1%-49% occlusion, 50%-75% occlusion, and >75% occlusion) with the 17-segment American Heart Association classification model. Discrepancies were settled by consensus. Effective radiation doses of prospective and retrospective CT angiography were calculated with volume CT dose index. Data regarding acquisition time and radiation exposure for prospective and retrospective CT angiography were compared. The Student t test was performed, and kappa statistics were calculated. RESULTS Mean data acquisition time of prospective CT angiography was shorter than that of retrospective CT angiography (5.6 seconds +/- 1.1 [standard deviation] vs 6.7 seconds +/- 1.1, respectively; P < .01). Consensus-determined image quality in coronary artery branches was similar between prospective CT angiography and retrospective CT angiography (1.15 vs 1.13, respectively; P = .992). Excellent agreement between prospective CT angiography and retrospective CT angiography was observed in the detection of significant (>or=50% occlusion) coronary artery stenoses per segment (kappa = 0.882) and in the grading of stenoses per patient (kappa = 0.829). Calculated effective dose with prospective CT angiography was 79% lower than that with retrospective CT angiography (4.1 mSv +/- 1.8 vs 20.0 mSv +/- 3.5, respectively; P < .001). CONCLUSION Prospective CT angiography can reduce radiation dose below that of retrospective CT angiography with dose modulation, while maintaining image quality and the ability to assess luminal obstructions in patients with heart rates of less than 75 beats per minute.

Accuracy of Sonographic Elastography in the Differential Diagnosis of Enlarged Cervical Lymph Nodes: Comparison with Conventional B-Mode Sonography

OBJECTIVE The purpose of our study was to evaluate the diagnostic performance of sonographic elastography and B-mode sonography individually and combined in the differentiation of reactively and metastatically enlarged cervical lymph nodes. SUBJECTS AND METHODS Eighty-five lymph nodes (metastatic, n = 53; reactive, n = 32) from 37 patients were examined by both elastography and B-mode sonography in this prospective study. Elastographic patterns were determined on the distribution and percentage of the lymph node area with high elasticity (hard), with pattern 1 being an absent or very small hard area to pattern 5, a hard area occupying the entire lymph node. The cutoff line for reactive versus metastatic was set between patterns 2 and 3; patterns 3-5 were considered metastatic. B-mode sonographic diagnosis was based on the sum of scores for five criteria: short-axis diameter, shape, border (regular or irregular), echogenicity (homogeneous or inhomogeneous), and hilum (present or absent). The cutoff line for reactive versus metastatic was set between scores 6 and 7; scores 5 and 6 were considered reactive, and scores 7-10, metastatic. RESULTS Sensitivity, specificity, and accuracy of B-mode sonography were 98%, 59%, and 84%, respectively; 83%, 100%, and 89% for elastography; and 92%, 94%, and 93% for the combined evaluation. CONCLUSION The combination of highly specific elastography with highly sensitive conventional B-mode sonography has the potential to further improve the diagnosis of metastatic enlarged cervical lymph nodes.

Radiofrequency Ablation Therapy Combined with Cementoplasty for Painful Bone Metastases: Initial Experience

The purpose of this study was to assess the efficacy and safety of percutaneous radiofrequency (RF) ablation therapy combined with cementoplasty under computed tomography and fluoroscopic guidance for painful bone metastases. Seventeen adult patients with 23 painful bone metastases underwent RF ablation therapy combined with cementoplasty during a 2-year period. The mean tumor size was 52 × 40 × 59 mm. Initial pain relief, reduction of analgesics, duration of pain relief, recurrence rate of pain, survival rate, and complications were analyzed. The technical success rate was 100%. Initial pain relief was achieved in 100% of patients (n = 17). The mean VAS scores dropped from 63 to 24 (p < 0.001) (n = 8). Analgesic reduction was achieved in 41% (7 out of 17 patients). The mean duration of pain relief was 7.3 months (median: 6 months). Pain recurred in three patients (17.6%) from 2 weeks to 3 months. Eight patients died and 8 patients are still alive (a patient was lost to follow-up). The one-year survival rate was 40% (observation period: 1–30 months). No major complications occurred, but one patient treated with this combined therapy broke his right femur 2 days later. There was transient local pain in most cases, and a hematoma in the psoas muscle (n = 1) and a hematoma at the puncture site (n = 1) occurred as minor complications. Percutaneous RF ablation therapy combined with cementoplasty for painful bone metastases is effective and safe, in particular, for bulky tumors extending to extraosseous regions. A comparison with cementoplasty or RF ablation alone and their long-term efficacies is needed.

Evaluation of coronary artery stenoses using electron-beam CT and multiplanar reformation.

PURPOSE We assessed the diagnostic value of electron-beam CT with multiplanar reformation for coronary artery stenoses. METHOD Thirty-seven patients who underwent conventional coronary angiography were evaluated with ECG-triggered thin section electron-beam CT with intravenous contrast enhancement. Multiplanar reformation of a stack of the images was performed to visualize coronary arteries. Two observers blind to the results of conventional coronary angiography independently evaluated the reformatted images. RESULTS The sensitivity and specificity for the detection of significant lesions were 100 and 100% in the left main coronary artery, 83 and 84% in the left anterior descending artery, 67 and 96% in left circumflex artery, 63 and 79% in the right coronary artery, and 74 and 94% for total results, respectively. All false-positive results in the left anterior descending artery were caused by wall calcification, and in the right coronary artery, 83% of the false-positive results were caused by small slice gaps in noncalcified segments. CONCLUSION Electron-beam CT was feasible for the detection of coronary artery stenoses. For interpretation of reformatted images, calcification and slice gaps should be taken into consideration.

Radiation-induced apoptosis and necrosis in Molt-4 cells : a study of dose-effect relationships and their modification

Cell death induced by various radiation doses in Molt-4 and L5178Y cells was studied. Molt-4 cells have a low threshold for induction of interphase death while L5178Y cells have a high threshold. Interphase death in Molt-4 cells at doses > 100 Gy and in L5178Y cells at doses > 300 Gy showed typical necrosis. In contrast, cell death in Molt-4 cells after 2-30 Gy had features of both apoptosis and necrosis; the appearance of orcein-stained cells in the light microscope was suggestive of apoptosis, showing chromatin margination and apoptotic bodies. The concomitant appearance of non-viable cells as estimated by either orcein staining or eosin dye staining correlated well with this. Early cell swelling and a diffuse smear pattern in DNA gel electrophoresis were however suggestive of necrosis. Detailed electron microscopic observations revealed that events leading to the interphase death of Molt-4 cells after 2-30 Gy involved complicated pathways which included both apoptotic changes in the nucleus and necrotic changes in the cytoplasm. TPA not only had a protective effect on the interphase death of Molt-4 cells, but also converted the mode of cell death from interphase death to mitotic death after low doses of radiation. Cycloheximide and H-7, known to inhibit apoptosis in irradiated thymocytes, had no protective effect on the interphase death of Molt-4 cells, suggesting that the events leading to interphase death in Molt-4 cells might be different from those in thymocytes. BrdUrd-labelling had a sensitizing effect on the radiation response, but no effect on interphase death in Molt-4 cells thus suggesting that DNA damage may not be responsible for interphase death.

Long-term Prognosis of Patients Undergoing Transcatheter Arterial Chemoembolization for Unresectable Hepatocellular Carcinoma: Comparison of Cisplatin Lipiodol Suspension and Doxorubicin Hydrochloride Emulsion

PURPOSE To evaluate long-term prognosis of transcatheter arterial chemoembolization (TACE) with use of cisplatin (CDDP) lipiodol (LPD) suspension (CDDP/LPD) compared with that with use of doxorubicin hydrochloride (ADM) LPD emulsion (ADM/LPD) in patients with unresectable hepatocellular carcinoma (HCC). MATERIALS AND METHODS One hundred eight patients were treated with use of CDDP/LPD and 26 were treated with use of ADM/LPD. Survival rates and frequency of side effects and complications in the CDDP/LPD group were compared with those in the ADM/LPD group. RESULTS CDDP/LPD was given at a dose of 15-70 mg (mean dose, 41 mg), whereas ADM/LPD was given at a dose of 20-100 mg (mean dose, 57 mg) throughout the study period. The survival rates in the CDDP/LPD group were 81% at 1 year, 41% at 3 years, 19% at 5 years, and 13% at 7 years, whereas those in the ADM/LPD group were 67% at 1 year, 18% at 3 years, and 0% at 5 years. The CDDP/LPD group showed significantly better survival than the ADM/LPD group (P <.05). In the CDDP/LPD group, there was a significant prolongation of survival in patients with monofocal HCC (P <.05) and patients with HCC assessed as an almost complete LPD accumulation (P <.05). There were no significant differences in survival rates in the ADM/LPD group according to tumor size and number of tumors. Hepatic failure was observed in 8% of all procedures and was not different between the two therapeutic groups. Renal dysfunction was observed in 2% of all treatments involving CDDP/LPD, and it resolved spontaneously with appropriate medications. CONCLUSIONS TACE with use of low-dose CDDP was efficacious for unresectable HCC and had few complications. TACE with use of CDDP may contribute to prolongation of the life span of patients with HCC versus TACE with use of ADM.

The long-term outcome of patients with bleeding gastric varices after balloon-occluded retrograde transvenous obliteration

BackgroundThe purpose of our study was to evaluate the long-term outcome and complications of balloon-occluded retrograde transvenous obliteration (B-RTO) in patients with hemorrhage from gastric fundal varices.MethodsThirty-four consecutive patients with bleeding from gastric varices who were treated with B-RTO were enrolled in this study between December 1994 and September 2005 (urgent cases, n = 12; elective cases, n = 22). The long-term outcome, complications, and various liver functions were evaluated.ResultsComplete obliteration was achieved in 31 of 34 (91%) patients with an acute bleeding episode. In one of the remaining patients, there was a technical failure, and the other two had only partial obliteration. The two patients with partial obliteration did not obtain hemostasis. Thus, the rate of hemostasis was 94% (31/33). Gastric varices disappeared in all patients with complete obliteration during the treatment. The rate of gastric variceal eradication was 91%. Variceal rebleeding from esophageal varices occurred in three patients. The rate of rebleeding was 10% (3/31). Rebleeding from gastric varices was not observed after complete obliteration. None of the patients showed worsening of their Child-Pugh score. Although the 5-year cumulative worsening rate of esophageal varices was 52%, neither portal hypertensive gastropathy nor ectopic varices were observed. The patients with worsening esophageal varices were successfully treated with an endoscopic procedure. The 5-year survival rate was 68%.ConclusionsB-RTO is useful for treatment of bleeding gastric varices, achieving high eradication of gastric varices, a low rebleeding rate, and a fairly good prognosis with improved hepatic function.

Optimum fractionation for high-dose-rate endoesophageal brachytherapy following external irradiation of early stage esophageal cancer

PURPOSE To establish the optimum fractionation for high-dose-rate (HDR) endoesophageal brachytherapy (EBT) for early stage esophageal cancer from retrospective data of patients treated with different HDR schedules following external beam irradiation (EBI). METHODS AND MATERIALS The study population consisted of 35 consecutive early stage esophageal cancer patients who received EBI to the mediastinum, plus EBT, between May 1992 and November 1995 at the Hiroshima University Medical Center and Hiroshima City Hospital. All patients were treated with EBI, with doses ranging from 50 to 61 Gy. The spinal cord was spared after 44-45 Gy. HDR EBT was performed using a double-balloon applicator in conjunction with an Ir-192 remote afterloading system. One group of 10 patients was given a weekly endoesophageal boost of 4 or 5 Gy at a distance of 5 mm from the applicator surface over a period of 1-2 weeks. Another group of 25 patients was treated with 4 or 5 endoesophageal boosts with a fraction dose of either 2.5 or 2 Gy for 1 week. The linear quadratic (LQ) formula was used to calculate the biologically effective dose (BED) for tumor (Gy10) and esophageal mucosa (Gy3); Gy10 means alpha/beta equals 10 Gy, and Gy3 means alpha/beta equals 3 Gy. The Kaplan-Meier method was used to calculate the local control and late complication rates, while the Cox-Mantel test was used to evaluate statistical significance (p < 0.01). RESULTS Nine (26%) of the 35 patients recurred locally and 7 (20%) had late complications (esophageal ulcer grade by RTOG/EORTC criteria > 1). The 5-year overall survival, local control, and late complication rates were 38%, 57%, and 26%, respectively. The probability of local recurrence was not affected by the treatment parameters. Results from the LQ formula significantly correlate with data on late complications. A BED > 134 Gy3 and a fraction number = < 3 were associated with late complications (grade > 1). BED analysis showed that the fractionation dose should be decreased to 2.5 or 2.0 Gy at a distance of 5 mm from the applicator surface, and the number of doses increased to 4 or 5, respectively, to yield a satisfactory BED (< 134 Gy3). CONCLUSION A significant reduction in endoesophageal brachytherapy dose per fraction is necessary to reduce late complications. Our current treatment protocol for early-stage esophageal cancer consists of EBI of 60 Gy followed by 4 EBT doses at a fraction dose of 2.5 Gy applied over 1 week.

Percutaneous radiofrequency ablation as first‐line treatment for small hepatocellular carcinoma: Results and prognostic factors on long‐term follow up

Background and Aims:  We evaluated the prognosis and associated factors in patients with small hepatocellular carcinoma (HCC; up to 3 nodules, each up to 3cm in diameter) treated with percutaneous radiofrequency ablation (RFA) as first‐line treatment.

Radiation Dose, Image Quality, Stenosis Measurement, and CT Densitometry Using ECG-Triggered Coronary 64-MDCT Angiography : A Phantom Study

OBJECTIVE The purpose of this study was to compare prospective ECG-triggered and retrospective ECG-gated coronary 64-MDCT angiography as to radiation dose, image quality, accuracy of stenosis measurement, and CT densitometry. MATERIALS AND METHODS Coronary artery models (n = 3) with different plaque densities (approximately 50, approximately 110, and approximately 1,000 H) on a cardiac phantom were scanned in variable heart rate sequences (n = 14) with both prospective ECG-triggered and retrospective ECG-gated scanning. Radiation dose, image quality graded by motion and stairstep artifacts (grade 1, excellent, to grade 4, poor, with grades 1 and 2 defined as satisfactory), accuracy of stenosis measurement (area; 18%, 50%, and 82%), and CT densitometry of plaques (soft, approximately 50; and intermediate, approximately 110 H) were compared between the two protocols using the Mann-Whitney U test and repeated measures. RESULTS The radiation dose of prospective ECG-triggered CT angiography (CTA) (3.0 mSv) was lower than that of retrospective ECG-gated CTA (11.7-13.0 mSv) when the same tube current (mA) and voltage (kVp) were used in both methods. Prospective ECG-triggered CTA images were assigned a satisfactory quality rating in stable heart rate up to 75 beats per minute (bpm) when using the minimal X-ray exposure time. In this range, there were no significant differences in stenosis measurement (p = 0.17) and CT densitometry (p = 0.93) between the two protocols. CONCLUSION Prospective ECG-triggered coronary 64-MDCT has the potential to reduce radiation exposure while maintaining the diagnostic performance of retrospective ECG-gated coronary 64-MDCT.