Novel T1 Analysis Method to Address Reduced Measurement Accuracy Due to Irregular Heart Rate Variability in Myocardial T1 Mapping Using Polarity-corrected Inversion Time Preparation

PURPOSE

Polarity-corrected inversion time preparation (PCTIP), a myocardial T1 mapping technique, is expected to reduce measurement underestimation in the modified Look-Locker inversion recover method. However, measurement precision is reduced, especially for heart rate variability. We devised an analysis using a recurrence formula to overcome this problem and showed that it improved the measurement accuracy, especially at high heart rates. Therefore, this study aimed to determine the effect of this analysis on the accuracy and precision of T1 measurements for irregular heart rate variability.

METHODS

A PCTIP scan using a 3T MRI scanner was performed in phantom experiment. We generated the simulated R-waves required for electrocardiogram (ECG)-gated acquisition using a signal generator set to 30 combinations. T1 map was generated using the signal train of the PCTIP images by nonlinear curve fitting using conventional and recurrence formulas. Accuracy against reference T1 and precision of heart rate variability were evaluated. To evaluate the fitting accuracy of both analyses, the relative fitting error was calculated.

RESULTS

For the longer T1, the fitting error was larger than the short T1, with the conventional analysis showing 10.1±2.0%. The recurrence formula analysis showed a small fitting error less than 1%, which was consistent for all heart rate variability patterns. In the conventional analysis, the accuracy, especially for longer T1, showed a large underestimation of the measurements and poor linearity. However, in the recurrence formula analysis, the accuracy improved at a long T1, and linearity also improved. The Bland-Altman plot showed that it varied greatly depending on the heart rate variability pattern for the longer T1 in the conventional analysis, whereas the recurrence formula analysis suppressed this variation.

CONCLUSION

T1 analysis of PCTIP using the recurrence formula analysis achieved accurate and precise T1 measurements, even for irregular heart rate variability.

Using Dictionary Matching to Improve the Accuracy of MOLLI Myocardial T1 Analysis and Measurements of Heart Rate Variability

We analyzed modified Look-Locker inversion recovery (MOLLI) T1 measurements by applying a dictionary matching strategy and aimed to acquire T1 measurements more accurately than those acquired by the conventional three-parameter matching analysis. We particularly clarified the robustness of this method for measuring heart rate (HR) variability. A phantom experiment using a 3T MRI system was performed for various HRs. The ideal MOLLI signal corresponding to the scan parameter in the MRI experiment was simulated over a wide range of T1 values according to the dictionary. The unknown T1 values were determined by finding the simulated signals in the dictionary corresponding to the measured signals using pattern matching. The measured T1 values showed that the proposed analysis improved the accuracy of T1 measurements compared to those acquired by traditional analysis by up to 10%. In addition, the variability of measurements at several HRs was reduced by up to 100 ms.

Effects of Lenvatinib on Skeletal Muscle Volume and Cardiac Function in Patients with Hepatocellular Carcinoma

INTRODUCTION

Previously, we reported that the tyrosine kinase inhibitor (TKI) sorafenib decreases serum levels of carnitine and reduces skeletal muscle volume. Moreover, others reported that TKIs might lead to cardiomyopathy or heart failure. Therefore, this study aimed to evaluate the effects of lenvatinib (LEN) on skeletal muscle volume and cardiac function in patients with hepatocellular carcinoma (HCC).

METHODS

This retrospective study included 58 adult Japanese patients with chronic liver diseases and HCC treated with LEN. Blood samples were collected before and after 4 weeks of treatment, and serum carnitine fraction and myostatin levels were measured. Before and after 4-6 weeks of treatment, the skeletal muscle index (SMI) was evaluated from computed tomography images and cardiac function was assessed by ultrasound cardiography.

RESULTS

After treatment, SMI, serum levels of total carnitine, and global longitudinal strain were significantly lower, but serum levels of myostatin were significantly higher. Left ventricular ejection fraction showed no significant change.

CONCLUSION

In patients with HCC, LEN decreases serum levels of carnitine, skeletal muscle volume, and worsens cardiac function.

Lenvatinib Might Induce Activation of Host Immunity in Patients with Hepatocellular Carcinoma

INTRODUCTION

Atezolizumab, an immune checkpoint inhibitor, plus bevacizumab, a monoclonal antibody that binds to vascular endothelial growth factor (VEGF), is an approved first-line systemic treatment for unresectable hepatocellular carcinoma (HCC). Immune checkpoint inhibitors are more effective in patients with HCC when administered with anti-VEGF drugs; however, these drugs affect host immunity. Lenvatinib is an anti-VEGF agent used to treat HCC; therefore, this study evaluated the effect of treatment of HCC with lenvatinib on host immunity in patients with chronic liver disease (CLD).

METHODS

We studied adult Japanese patients with CLD and unresectable HCC treated with lenvatinib at our hospital. Lenvatinib was administered for 4 weeks (8 mg/day for bodyweight <60 kg; 12 mg/day for bodyweight >60 kg). Blood samples were collected at baseline and at 4 weeks of treatment and examined for immune-related changes.

RESULTS

Forty-three patients were enrolled in this study. We found a significant increase in T helper (Th) 1 cells following 4 weeks of lenvatinib treatment, although there was no significant difference in Th2 cells and regulatory T cells. We also found a significant increase in serum levels of TNF-alpha, soluble TNF-alpha receptor I, and endothelial growth factor following 4 weeks of lenvatinib treatment. Furthermore, an increase in Th1 cells and serum levels of TNF-alpha was found in patients with partial response.

CONCLUSION

Lenvatinib might induce Th1-dominant host immunity in patients with CLD and unresectable HCC treatment in patients who showed a partial response. These changes in host immunity may be a biomarker in HCC patients treated with lenvatinib.

Tivantinib Decreases Hepatocyte Growth Factor-Induced BCRP Expression in Hepatocellular Carcinoma HepG2 Cells

Tivantinib, a mesenchymal-epithelial transition factor (cMET) inhibitor, is a molecular targeting drug that kills hepatocellular carcinoma (HCC) cells. Tivantinib alone does not affect the overall survival of patients with HCC, and combination treatment with tivantinib and other therapies has not been evaluated. This study was conducted to clarify the effect of the tivantinib in regulating breast cancer therapy-resistant protein (BCRP), a key transporter of 5-fluorouracil (5-FU), and dihydropyridine dehydrogenase (DPYD), a major metabolic enzyme of 5-FU. To this end, cMET gene expression was determined by RT-PCR in HepG2 (human hepatoma) cells. The transcriptional start sites of BCRP were determined by 5'-rapid amplification of cDNA ends (5'-RACE). BCRP and DPYD mRNA levels were determined by real-time RT-PCR, and promoter activities were measured by dual-luciferase assays. Results show that hepatocyte growth factor (HGF) upregulated the mRNA level of BCRP, but not DPYD, in HepG2 cells. The upregulation of BCRP expression by HGF was down-regulated by tivantinib. We also identified two transcriptional start sites (E1α, E1β) in BCRP by 5'-RACE. The transcriptional activity of the region -287 to E1α of BCRP was upregulated by HGF, which was decreased by tivantinib, whereas activity of the region -297 to E1βo f BCRP was not affected by tivantinib. Therefore, tivantinib regulates BCRP expression upstream of exon 1α. Combination treatment of tivantinib and 5-FU should be further evaluated for HCC therapy.

Usefulness of virtual touch tissue quantification for predicting the presence of esophageal varices in patients with liver cirrhosis

BACKGROUND AND AIM

Measuring the hepatic venous pressure gradient (HVPG) is an established technique to detect increased portal pressure and predict the presence of esophageal varices (EVs); however, the risk of the test is greater than the information it provides. This study aimed to clarify the usefulness of virtual touch tissue quantification (VTQ), which assesses liver stiffness, in predicting the presence of EVs in patients with liver cirrhosis by comparing it with HVPG.

METHODS

Two hundred seventeen patients with liver cirrhosis underwent VTQ, HVPG measurement, and upper endoscopy. Patients were divided into three groups: group V, hepatitis C virus liver cirrhosis (n = 40); group A, alcoholic liver cirrhosis (n = 116); and group N, other liver cirrhosis (n = 61). In each group, we performed linear regression analysis of VTQ and HVPG data. The accuracy of VTQ and HVPG measurement in predicting the presence of EVs and high-risk EVs (EV category F2 and F3) was assessed by area under the receiver operating characteristic curve (AUROC).

RESULTS

VTQ was significantly correlated with the HVPG in the whole patients and in each group, and both VTQ and HVPG values were significantly higher in patients with EVs and high-risk EVs than in those without. The AUROC for the presence of EVs for VTQ was 0.76 in the whole sample, 0.76 in group V, 0.79 in group A, and 0.67 in group N; and for HVPG, 0.92, 0.94, 0.93, and 0.88, respectively. For VTQ, the AUROC for the presence of high-risk EVs was 0.78 in the whole sample, 0.78 in group V, 0.73 in group A, and 0.73 in group N; and for HVPG, it was 0.85, 0.82, 0.85, and 0.82, respectively.

CONCLUSION

VTQ was reliable at predicting the presence of EVs and high-risk EVs. Therefore, we propose that VTQ is a useful, noninvasive tool for predicting the presence of EVs in daily medical care.

Successful treatment of advanced pancreatic leiomyosarcoma treated with gemcitabine plus nab-paclitaxel: a case report and literature review

Pancreatic leiomyosarcoma (PLMS) is an extremely rare tumor that accounts for 0.1% of pancreatic malignancies, and its chemotherapy has yet to be established. Generally, soft-tissue sarcoma chemotherapy is standard treatment with doxorubicin (DXR) alone. However, the effectiveness of gemcitabine (GEM) plus docetaxel (DOC) has been shown in uterine leiomyoma. In contrast, the GEM plus nab-paclitaxel (PTX) regimen has been established as first-line chemotherapy for unresectable pancreatic cancer. For this study, we selected the GEM plus nab-PTX regimen for patients with PLMS, achieving success in approximately 10 months. From a search on PubMed, we found only 12 cases of PLMS (including this case) that underwent chemotherapy. Our case is the first reported patient to have survived more than 2 years with chemotherapy alone. In a nude mouse model, the GEM plus DOC regimen was shown to significantly decrease tumor size when compared with DXR in leiomyosarcoma, and the GEM plus nab-PTX regimen was reported to significantly reduce necrosis when compared with DXR alone, GEM alone, DOC alone, nab-PTX alone and GEM plus DOC in soft-tissue sarcoma. GEM plus nab-PTX therapy might therefore be the first choice for soft-tissue sarcoma and leiomyosarcoma. This is the first reported case of PLMS treated with GEM plus nab-PTX.

Sorafenib Might Induce Sarcopenia in Patients With Hepatocellular Carcinoma by Inhibiting Carnitine Absorption

BACKGROUND/AIM

Tyrosine kinase inhibitors (TKIs) have revolutionized the treatment of cancers. Sorafenib, an oral multi-target TKI, improves the median overall survival time in patients with hepatocellular carcinoma (HCC). It also inhibits the absorption of carnitine by down-regulating the human organic cationic transporter OCTN2 located largely in the small intestinal mucosa and skeletal muscle. The aim of the study was to determine, by assessing carnitine metabolism, whether sarcopenia is induced in patients with HCC who are receiving sorafenib.

PATIENTS AND METHODS

This retrospective study included 110 adult Japanese patients with liver cirrhosis and HCC who received sorafenib. Sorafenib was administered at a dose of 200-800 mg/day for 4 weeks. Blood samples were collected before and after treatment, and serum carnitine fraction and myostatin levels were measured. Cross-sectional areas (cm²) of the skeletal muscles at the third lumbar vertebra level were determined by manually outlining computed tomography images before and after treatment. The cross-sectional areas were normalized for height [skeletal muscle index (SMI), cm²/m²].

RESULTS

Patients were allocated to two groups according to Child-Pugh (CP) class; 81 had CP-A liver function, and 29 had CP-B. SMI after treatment was significantly lower than that before treatment in both groups. Serum levels of total carnitine and free carnitine after treatment were significantly lower than those before treatment in both groups. There were no differences in serum levels of myostatin before and after treatment in either group.

CONCLUSION

Sorafenib might decrease serum levels of carnitine by inhibiting carnitine absorption. Decreasing of serum levels of carnitine might lead to presarcopenia.

Flash Imaging Used in the Post-vascular Phase of Contrast-Enhanced Ultrasonography is Useful for Assessing the Progression in Patients with Hepatitis C Virus-Related Liver Disease

Sonazoid is a commonly used contrast agent for characterizing liver tumors in ultrasonography (US). We performed flash imaging in the post-vascular phase of contrast-enhanced US (CEUS) to investigate associations between collapse of Sonazoid microbubbles (MB) and progression of liver disease. This study enrolled 409 patients (205 men, 204 women) with hepatitis C virus-related liver disease (CLD) between 2007 and 2017 (mean age 60 ± 14 y; range 20-90 y). In the post-vascular phase, 10 min after administering Sonazoid, flash imaging was performed to burst MB in the liver parenchyma; the range of bubble destruction was measured from the surface of the liver. The range of bubble destruction, stage of fibrosis, shear wave velocity (Vs), serologic markers and fibrosis-4 (FIB4) index were analyzed in 259 patients who underwent liver biopsy. Fibrosis stage was F0-1 in 108 patients, F2 in 73, F3 in 38 and F4 in 40. In 150 patients with cirrhosis, diagnosis was made based on imaging findings. The range of bubble destruction was 42.0 ± 10.4 mm in F0-1 patients, 42.9 ± 13.2 mm in F2, 51.5 ± 15.9 mm in F3 and 55.4 ± 17.3 mm in F4 and was significantly increased according to progression of fibrosis staging. The range of bubble destruction was positively correlated with Vs (r = 0.34; p < 0.01), total bilirubin (r = 0.25; p < 0.01) and FIB4 index (r = 0.38; p < 0.01). In contrast, the range of bubble destruction was negatively correlated with serum levels of albumin (r = -0.34; p < 0.01), platelet count (r = -0.35; p < 0.01) and prothrombin time (r = -0.36; p < 0.01). The results indicated that flash imaging in the post-vascular phase of CEUS was a non-invasive assessment and could predict disease progression in patients with CLD.

Influence of Sorafenib on Host Immunity in Patients with Liver Cirrhosis With Advanced Hepatocellular Carcinoma Stratified by Etiology

AIM

We previously reported that sorafenib induces Th1 [interferon-γ (IFNγ)-positive interleukin 4 (IL4)-negative] dominance which prevents tumor cells from escaping the host immune system in patients with liver cirrhosis (LC) and advanced hepatocellular carcinoma (aHCC). However, in that study we did not assess the influence of sorafenib on host immunity according to the etiology of LC. Therefore, this study was retrospectively performed to evaluate the impact of sorafenib therapy for aHCC on host immunity in patients stratified according to the etiology of LC: Patients and Methods: A total of 116 adult Japanese patients with LC and aHCC received sorafenib therapy at our hospital. Blood samples were collected before and after treatment for 4 weeks.

RESULTS

Twenty-two patients had hepatitis B virus (HBV)-related LC, 62 patients had hepatitis C virus (HCV)-related LC, 22 patients had alcoholic LC, and 10 patients had LC without these causative factors. In patients receiving sorafenib at a dose of 400 mg/day, patients in Child-Pugh class A, and patients with stage IVA aHCC, Th2 (IFNγ-negative/IL4-positive) cells decreased significantly after treatment, although there was no significant impact on the tumor response. In addition, Th2 cells decreased significantly in patients with HCV-related LC after treatment, while there were no significant changes in the other groups.

CONCLUSION

Sorafenib might prevent tumor cells from escaping the host immune system in patients with aHCC and HCV-related LC, although it does not seem to do so in those with LC of other etiologies.

[Coronary Computed Tomography Angiography for Patients with Atrial Fibrillation: Feasibility of Prospective Electrocardiography-gated Diastolic Acquisition with a Manual Exposure-termination Technique]

Coronary computed tomography angiography (CCTA) was performed in 283 patients with atrial fibrillation (Af) using a prospective electocardiogeaphic gated scanning with a manual exposure-termination technique. When preparatory 5-beat scanning contained at least one RR interval longer than 800 ms, 5-beat diastolic scanning (R+800 ms protocol) was selected. When no RR interval longer than 800 ms was observed, 2-beat scanning starting at end-systolic phase (R+210 ms to R protocol) was chosen. In R+800 ms protocol, we manually terminated scanning when motion free real-time reconstruction image was confirmed. R+800 ms protocol was applied in 95% of the cases and required an average of 2 cardiac cycles, providing motion-free images in 91% of the patients. The mean exposure dose was less than that with R+210 ms to R protocol. Using the protocols above, 90% of the all patients with Af provided motion free images and 99% of them were evaluable.

Pacemaker-induced Metallic Artifacts in Coronary Computed Tomography Angiography: Clinical Feasibility of Single Energy Metal Artifact Reduction Technique

BACKGROUND

Coronary computed tomography angiography (CCTA) in patients with pacemaker suffers from metallic lead-induced artifacts, which often interfere with accurate assessment of coronary luminal stenosis. The purpose of this study was to assess a frequency of the lead-induced artifacts and artifact-suppression effect by the single energy metal artifact reduction (SEMAR) technique.

METHODS

Forty-one patients with a dual-chamber pacemaker were evaluated using a 320 multi-detector row CT (MDCT). Among them, 22 patients with motion-free full data reconstruction images were the final candidates. Images with and without the SMEAR technique were subjectively compared, and the degree of metallic artifacts was compared.

RESULTS

On images without SEMAR, severe metallic artifacts were often observed in the right coronary artery (#1, #2, #3) and distal anterior descending branch (#8). These artifacts were effectively suppressed by SEMAR, and the luminal accessibility was significantly improved in #3 and #8.

CONCLUSION

While pacemaker leads often cause metallic-induced artifacts, SEMAR technique reduced the artifacts and significantly improved the accessibility of coronary lumen in #3 and #8.

Single injection protocol for coronary and lower extremity CT angiographies in patients suspected for peripheral arterial disease

To evaluate the feasibility of a single injection protocol for coronary CT angiography (CTA) and lower extremity CTA in patients suspected for peripheral arterial disease (PAD).This prospective observational study included a total of 103 patients who showed an ankle brachial index ≤0.9 and underwent the single injection protocol for coronary and lower extremity CTA. All CTAs used iodinated contrast (weight × 0.06 mL/s × 20 seconds). A prospective Electrocardiogram (ECG)-gated coronary CTA was performed, followed by helical lower extremity CTA beginning 9 seconds after coronary CTA. Using catheter angiography as reference standard, diagnostic ability of CTA was evaluated.The mean total volume of iodinated contrast used was 70 ± 14 mL. Contrast opacification in the superficial femoral artery was adequate (408 ± 97  Hounsfield Units [HU]) and PAD was detected in 72.8% (75/103). The estimated radiation doses for lower extremity and coronary CTA were 3.6 ± 1.2 and 5.5 ± 4.5 mSv. A significant coronary stenosis was detected in 47 patients (45.6%). Coronary CT image quality was recorded as excellent in 86.4%, acceptable in 11.7%, and unacceptable for 1.9%. Contrast opacification within the superficial femoral artery was adequate in all cases while 27.2% needed an additional scan below the calf to capture the contrast bolus arrival in the smaller lower extremity vessels. Segment based sensitivity, specificity, positive, and negative predictive values were 57.9%, 97.9%, 73.8%, and 95.9% for the coronary CTA, and 63.4%, 91.5%, 76.3%, and 85.3% for peripheral CTA.A single injection protocol for coronary CTA and lower extremity CTA is feasible with a relatively small volume of iodinated contrast.

[The Minimum Values of (RR-PQ) for High Quality Coronary CT Angiogram in Half, Automatic Patient's Motion Correction (APMC) and Full Reconstruction Using 320-ADCT (0.275 s/r)]

BACKGROUND

A clear coronary CT angiography (CCTA) can be obtained when temporal resolution (TR) is shorter than slow filling (SF) duration. The SF duration was calculated by the following equation: SF=-443+0.742 (RR-PQ). Although, the TR of half and full reconstruction using 320-ADCT (0.275 s/r) are known, the TR of automatic patient motion correction (APMC) reconstruction is not clear. The purpose of this study is to clarify the each minimum value of (RR-PQ) for acquiring a clear CCTA that was made by half, full or APMC reconstruction.

METHOD

CCTA was performed in consecutive 345 (M/F=195/150, Age: 69±10 years) patients except for arrhythmia and the final heart rate (controlled by β-blocker) ≥80 bpm using 320-ADCT (Aquilion ONE, 0.275 s/r). In all subjects, 3 CCTAs were generated by half, full, or APMC reconstruction at the same optimal phase. Image quality (A: excellent, B: acceptable, C: poor) was estimated by the consensus of three trained researchers. We classified (RR-PQ) into 15 groups by each 50 ms interval.

RESULTS

The A or B % prediction (y) significantly correlated (y=-240.08+0.401x, r=0.98, p=0.0006 in half, y=-238.26+0.378x, r=0.98, p=0.0001 in APMC, and y=-236.84+0.332x, r=0.97, p<0.0001 in full reconstruction) with (RR-PQ) (x), respectively.

CONCLUSION

The minimum values of (RR-PQ) for 95% prediction of A or B image quality were ≥836 ms in half, ≥881 ms in APMC, and ≥998 ms in full reconstruction.

Coronary Whole-heart MR Angiography: Feasibility of Breath-hold Chasing with Diaphragmatic Navigation

We propose a simple but novel data acquisition technique for whole-heart coronary magnetic resonance angiography (CMRA). In this technique, the breath-hold chasing MRA, data are collected during breath-hold intervals, with the navigation window manually adjusted to the diaphragmatic level. Compared with the conventional free breathing MRA, this method provided 33% reduction of acquisition time and improved visibility of right coronary artery in 18 normal subjects without any additional software or hardware requirements.

Assessment of coronary in-stent restenosis: value of subtraction coronary computed tomography angiography

In conventional coronary computed tomography angiography (CCTA), metal artifacts are frequently observed where stents are located, making it difficult to evaluate in-stent restenosis. This study was conducted to investigate whether subtraction CCTA can improve diagnostic accuracy in the evaluation of in-stent restenosis. Subtraction CCTA was performed using 320-row CT in 398 patients with previously placed stents who were able to hold their breath for 25 s and in whom mid-diastolic prospective one-beat scanning was possible. Among these patients, 126 patients (94 men and 32 women, age 74 ± 8 years) with 370 stents who also underwent invasive coronary angiography (ICA) were selected as the subjects of this study. With ICA findings considered the gold standard, conventional CCTA was compared against subtraction CCTA to determine whether subtraction can improve diagnostic accuracy in the evaluation of in-stent restenosis. When non-assessable stents were considered to be stenotic, the diagnostic accuracy in the evaluation of in-stent restenosis was 62.7 % for conventional CCTA and 89.5 % for subtraction CCTA. When the non-assessable stents were considered to be non-stenotic the diagnostic accuracy was 90.3 % for conventional CCTA and 94.31 % for subtraction CCTA. When subtraction CCTA was used to evaluate only the 138 stents that were judged to be non-assessable by conventional CCTA, 116 of these stents were judged to be assessable, and the findings for 109 of them agreed with those obtained by ICA. Even for stents with an internal diameter of 2.5-3 mm, the lumen can be evaluated in more than 80 % of patients. Subtraction CCTA provides significantly higher diagnostic accuracy than conventional CCTA in the evaluation of in-stent restenosis.

Incremental predictive value for obstructive coronary artery disease by combination of Duke Clinical Score and Agatston score

AIMS

Recent study suggests that algorithms such as the Duke Clinical score (DCS) may overestimate the pretest probability. The Agatston score representing the grade of coronary artery calcification can be simply calculated from low-radiation exposure ECG-gated plain CT. In this study, we investigated whether or not more superior diagnostic performance for obstructive coronary artery disease (CAD) can be obtained by combining DCS with the Agatston score.

METHODS AND RESULTS

Of 3939 consecutive patients suspected of having stable angina without known CAD who underwent Coronary Computed Tomography Angiography (CCTA) as well as calculation of the DCS and Agatston score at our hospital, 3688 patients were selected as subjects. Obstructive CAD was defined as >50% diameter stenosis on CCTA; we investigated the diagnostic performance based on the area under the curve (AUC) of a receiver operating characteristic (ROC) curve, Net Reclassification Improvement (NRI), and Integrated Discrimination Improvement (IDI). The AUCs of ROCs prepared using the DCS alone and combination of the DCS and Agatston score were 0.7137 and 0.8057, respectively, showing that the diagnostic performance of the combination was significantly superior to DCS alone (P < 0.001). NRI was 0.8132 and IDI was 0.1374, showing that the diagnostic performance was improved by the combination of the DCS and Agatston score compared with DCS alone (P < 0.001). NRI (0.3522) and IDI (0.0287) were improved compared with those of the Agatston score alone (P < 0.001).

CONCLUSION

The combination of the DCS and Agatston score improved the diagnostic performance for obstructive CAD compared with DCS alone and Agatston score.

[Clinical usefulness of low tube current scanning with full reconstruction and automatic patient motion correction (APMC) reconstruction in a prospective ECG-gated coronary CT angiography using 320-row area detector CT]

PURPOSE

The purpose of this study is to validate the clinical usefulness of Advanced Patient Motion Correction (APMC) reconstruction when motion artifacts were observed in a prospective ECG-gated coronary CT angiography (CCTA), which was acquired by low tube current scanning with full reconstruction using 320-row area detector CT (0.275 s/rot.).

METHODS

Of 530 consecutive CCTA, we selected 119 patients (M/F: 71/48, Age: 69 ± 11 y, BMI: 23.5 ± 2.5) with (RR-PQ) ≥ 968 ms before scanning, and performed a CCTA with low tube current scanning [30% of usual tube current (30%mA)], adaptive iterative dose reduction 3D, and full reconstruction. Image quality for motion artifacts was subjectively evaluated using a 3-point scale (excellent, acceptable, and unacceptable).

RESULTS

Of 119, 102 CCTA had "excellent" images (group A) and 17 had "acceptable" images (group B). The APMC and half reconstruction were retried in the 17 CCTA with "acceptable" images. Finally, all CCTA became "excellent" images. The RR-PQ of group B during scanning (966 ± 80 ms) was significantly (P = 0.0001) shorter than group A (1,088 ± 123 ms). Each image noise (standard deviation of CT value) of aorta, left atrium, and left ventricle was 21.7 ± 2.3, 24.7 ± 2.3, 24.5 ± 2.4 in full, 25.7 ± 2.2, 29.0 ± 3.4, 28.2 ± 2.7 in APMC, and 30.4 ± 2.8, 34.3 ± 4.2, 33.3 ± 2.9 HU in half reconstruction. Mean dose-length product of all patients was 66.2 ± 34.4 mGy · cm.

CONCLUSION

"Excellent" CCTA images can be obtained in 85.7% of patients with (RR-PQ)≥ 968 ms by full reconstruction. APMC is useful for motion artifacts and image noise reduction when patient' s HR increases during scanning rather than half reconstruction.

Repeat coronary computed tomographic angiography in patients with a prior scan excluding significant stenosis

BACKGROUND

ACCF/SCCT/ACR/AHA/ASE/ASNC/NASCI/SCAI/SCMR 2010 Appropriate Use Criteria for Cardiac Computed Tomography (AUC2010) does not incorporate prior coronary computed tomographic angiography (CCTA) results in the appropriateness of a CCTA examination. The purpose of this study was to explore the criteria for forgoing repeat CCTA among patients with clinical scenarios suggesting CCTA as appropriate after prior CCTA excluding coronary artery disease.

METHODS AND RESULTS

Among patients from a single center (February 2006 to April 2013) who underwent appropriate CCTA based on AUC2010, consecutive 555 CCTAs, which had a prior CCTA excluding significant stenosis (>50% stenosis in diameter), were selected. The median time difference between the studies was 34.2 (Q1-Q3, 22.9-50.1) months. Significant stenosis was detected at the time of repeat scan (by CCTA or subsequent catheter angiography) in 13.3% (74 of 555). A multivariable logistic model (C-statistic, 0.74; bootstrapped overfitting bias, 0.8%) identified 3 predictors of significant stenosis: time difference between the studies >3 years (adjusted odds ratio, 2.1; 95% confidence interval, 1.2-3.5), diabetes mellitus (odds ratio, 2.4; 95% confidence interval,1.4-4.3), and 26% to 50% stenosis on the initial CCTA (odds ratio, 5.6; 95% confidence interval, 3.2-9.6). When these 3 factors were all absent (corresponding to 31.9% of the population), the probability of significant stenosis was 4.5% (95% confidence interval, 2.7-7.4%), whereas 17.1% of patients had significant stenosis among those with at least 1 positive variable. When coronary arteries were completely normal at the initial scan, the prevalence of significant stenosis was only 1.8% irrespective of other factors, and no patient underwent revascularization.

CONCLUSIONS

Nondiabetic patients with a prior CCTA <3 years showing no or ≤25% stenosis had a <5% prevalence of significant stenosis. The value of repeat CCTA in this group is likely small, especially when the prior CCTA demonstrated normal coronaries, even if the clinical scenario considered a CCTA appropriate.

Superficial siderosis of the central nervous system caused by hemorrhagic intraventricular craniopharyngioma: case report and literature review

Superficial siderosis is a rare condition caused by hemosiderin deposits in the central nervous system (CNS) due to prolonged or recurrent low-grade bleeding into the cerebrospinal fluid (CSF). CNS tumor could be one of the sources of bleeding, both pre- and postoperatively. We report an extremely rare case of superficial siderosis associated with purely third ventricle craniopharyngioma, and review previously reported cases of superficial siderosis associated with CNS tumor. A 69-year-old man presented with headache, unsteady gait, blurred vision, and progressive hearing loss. Brain magnetic resonance (MR) imaging with gadolinium revealed a well enhanced, intraventricular mass in the anterior part of the third ventricle. T₂*-weighted gradient echo (GE) MR imaging revealed a hypointense rim around the brain particularly marked within the depth of the sulci. Superficial siderosis was diagnosed based on these findings. The tumor was diffusely hypointense on T₂*-weighted GE imaging, indicating intratumoral hemorrhage. The lateral ventricles were dilated, suggesting hydrocephalus. [¹⁸F]fluorodeoxyglucose positron emission tomography revealed increased uptake in the tumor. The whole brain surface appeared dark ocher at surgery. Histological examination showed the hemorrhagic tumor was papillary craniopharyngioma. His hearing loss progressed after removal of the tumor. T₂*-weighted GE MR imaging demonstrated not only superficial siderosis but also diffuse intratumoral hemorrhage in the tumor. Superficial siderosis and its related symptoms, including hearing loss, should be considered in patients with hemorrhagic tumor related to the CSF space. Purely third ventricle craniopharyngioma rarely has hemorrhagic character, which could cause superficial siderosis and progressive hearing loss.

A novel GJA1 mutation in oculodentodigital dysplasia with progressive spastic paraplegia and sensory deficits

Oculodentodigital dysplasia (ODDD) is a rare autosomal dominant inherited disorder mainly affecting the development of the face, eyes, dentition, limbs, hair and heart. GJA1 (the gap junction protein α-1) has been determined to be a causative gene of ODDD, mapped to chromosome 6q22-24 identified as the connexin 43 gene (Cx43). We found a novel GJA1 mutation (W25C) as the possible causative gene in this sporadic ODDD patient with neurological features of motor deficits by pyramidal tract signs, and sensory deficits due to peripheral nerve disturbance. It is also notable that the MRI of this patient demonstrated widespread aberrant signal lesions in the brain and brainstem.

Non-Contrast Renal MR Angiography: Value of Subtraction of Tagging and Non-Tagging Technique

PURPOSE

The aim of this study was to examine the usefulness of the subtraction technique of non-contrast renal magnetic resonance angiography (MRA) between tagged and non-tagged data collection.

MATERIAL AND METHODS

We performed renal MRA on eleven healthy volunteers using a 3T MRI unit. For renal MRA, a three dimensional balanced type steady-state free precession (SSFP) sequence (True FISP, Siemens) was used with diaphragmatic navigator gating. We tried to acquire selective arterial images by subtracting black-blood images (tagged images, on which arterial longitudinal magnetization was nearly zero by selective inversion of upper-stream aortic flow) from bright-blood images (non-tagged images, on which arterial flow is bright due to inflow effect). For analysis, two radiologists independently evaluated the visual quality of the axial and coronal targeted maximum intensity projection images (MIP) of original bright-blood MRA and subtraction MRA.

RESULTS

Visualization of the main stem of the renal arteries and their 1st branches were satisfactory on both techniques, and there was no statistically significant difference. The score of 2nd branch appeared superior with the subtraction method, but only the right side showed a statistically significant difference (P <0.01). Visualization of small intraparenchymal arteries was significantly superior with subtraction method on both sides.

CONCLUSION

We tried to improve selective demonstration of renal arterial branches using subtraction technique. Although full sequence optimization was not performed, this pilot study showed this technique to be slightly time-consuming but superior in visualization of peripheral branches and possibly more sensitive in detecting small vessel abnormalities.

Associations among parenting experiences during childhood and adolescence, hypothalamus-pituitary-adrenal axis hypoactivity, and hippocampal gray matter volume reduction in young adults

Recent human studies have indicated that adverse parenting experiences during childhood and adolescence are associated with adulthood hypothalamus-pituitary-adrenal (HPA) axis hypoactivity. Chronic HPA axis hypoactivity inhibits hippocampal gray matter (GM) development, as shown by animal studies. However, associations among adverse parenting experiences during childhood and adolescence, HPA axis activity, and brain development, particularly hippocampal development, are insufficiently investigated in humans. In this voxel-based structural magnetic resonance imaging study, using a cross-sectional design, we examined the associations among the scores of parental bonding instrument (PBI; a self-report scale to rate the attitudes of parents during the first 16 years), cortisol response determined by the dexamethasone/corticotropin-releasing hormone test, and regional or total hippocampal GM volume in forty healthy young adults with the following features: aged between 18 and 35 years, no cortisol hypersecretion in response to the dexamethasone test, no history of traumatic events, or no past or current conditions of significant medical illness or neuropsychiatric disorders. As a result, parental overprotection scores significantly negatively correlated with cortisol response. Additionally, a significant positive association was found between cortisol response and total or regional hippocampal GM volume. No significant association was observed between PBI scores and total or regional hippocampal GM volume. In conclusion, statistical associations were found between parental overprotection during childhood and adolescence and adulthood HPA axis hypoactivity, and between HPA axis hypoactivity and hippocampal GM volume reduction in healthy young adults, but no significant relationship was observed between any PBI scores and adulthood hippocampal GM volume.

Blood flow change quantification in cervical cancer before and during radiation therapy using perfusion CT

The purpose of this study was to quantify the changes of tumor blood flow (BF) in cervical cancer after radiation therapy by using perfusion computed tomography (CT), and to examine the difference between maximum slope (MS) and single-input one-compartment model (SOCM) methods. Fourteen consecutive patients who received definitive radiation therapy for cervical cancer from October 2009 to February 2010 were enrolled in this study. Blood flow (BF) analyses were performed using both MS and SOCM methods. Quantitative BF maps were created using Body Perfusion (Toshiba Medical Systems, Co. Tokyo, Japan). Perfusion color maps were successfully created by the two analytical methods. BF of the tumors was clearly higher than that of normal cervix, making it possible to distinguish tumor tissue from normal cervical tissue. BF of the tumors after 20 Gy of radiation therapy calculated by the MS method was significantly larger than that before treatment (126.9 vs. 72.2 ml/min/100 ml, median; p < 0.05). Although BF calculated by the MS and SOCM methods showed a positive linear correlation (p < 0.001, r = 0.981), BF calculated by the MS method was lower than that obtained by the SOCM method (103.7 vs. 115.1 ml/min/100 ml, p < 0.01). The change of tumor BF in cervical cancer before and after radiation therapy can be monitored by conducting blood flow analysis using perfusion CT. BF by the MS method was lower than that by the SOCM method, but the two analytical methods correlated well. Perfusion CT may have potential in noninvasive monitoring of vascular and oxygenation status and for guiding adaptive therapy.

Relationship of parental bonding styles with gray matter volume of dorsolateral prefrontal cortex in young adults

Previous epidemiologic studies using the parental bonding instrument (PBI), a self-report scale to rate attitudes of parents during the first 16 years, have suggested that a lower parental care score or higher parental overprotection score could lead to an increased risk of several psychiatric disorders, including schizophrenia and mood disorder. However, neuroimaging studies of an association between PBI scores and brain developmental abnormalities are still limited. In this region-of-interest analysis study using a cross-sectional design, we examined 50 normal young adults, in terms of relationships of parental bonding styles during the first 16 years measured by PBI with regional gray matter (GM) volume in the dorsolateral prefrontal cortex (DLPFC). Our study showed that paternal care score positively correlated with the GM volume in the left DLPFC, and paternal and maternal overprotection score negatively correlated with the GM volume in the left DLPFC. In conclusion, our results suggest that in normal young adults, lower paternal care and higher parental overprotection scores correlated with the GM volume reduction in the DLPFC.

Added value of contrast-enhanced CISS imaging in relation to conventional MR images for the evaluation of intracavernous cranial nerve lesions

INTRODUCTION

The normal cranial nerves (CNs) of the cavernous sinus can be clearly demonstrated using contrast-enhanced constructive interference in steady-state (CISS) magnetic resonance imaging (MRI). This study used the method to evaluate pathological CNs III, IV, V(1), V(2), and VI in cavernous sinuses affected by inflammatory and neoplastic diseases.

METHODS

MR images from 17 patients with diseases involving the cavernous sinuses and/or causing neuropathy in CNs III-VI were retrospectively evaluated. The patients were divided into inflammatory (n=11) and neoplastic (n=6) groups. We defined CNs as abnormal when they exhibited enlargement or enhancement. CNs were evaluated using both contrast-enhanced CISS and T1-weighted MRI.

RESULTS

In the inflammatory group, abnormal CNs were identified by contrast-enhanced CISS MRI in 13 of 25 symptomatic CNs (52%) in eight patients, but in only two CNs (8%) in two patients by contrast-enhanced T1-weighted MRI. In the neoplastic group, both sequences of contrast-enhanced CISS and T1-weighted MRI detected abnormalities in the same three of eight symptomatic CNs (37.5%), i.e., the three CNs were all in the same patient with adenoid cystic carcinoma.

CONCLUSION

Contrast-enhanced CISS MRI is useful for detecting CN abnormalities in inflammatory pathological conditions of the cavernous sinuses.

[Evaluation of exposure dose for panoramic radiography]

PURPOSE

There is no established method to determine a diagnostic reference level of panoramic radiology. As the basic principle of the panoramic radiology dose index (PRDI) and CT dose index (CTDI) is almost identical, we evaluated the usefulness of PRDI for this purpose.

METHODS

Using the imaging plate (IP) sandwiched between the 160-mm thick acrylic disks, horizontal radiation dose distribution was analyzed by the conventional radiographic technique. Panoramic exposure dose was measured using the CT ionizing chamber that was placed at the tracking focus. Beam height was used as measurement unit, and PRDI was normalized and calculated.

RESULTS

There were two foci showing the maximum exposure dose for this panoramic equipment, located symmetrically 45 mm away from the center of the object. The PRDI of medium-sized individuals measured by this method was 0.74 mGy.

CONCLUSION

We suggested a method to evaluate a diagnostic reference level, measuring the dose of exposure focus, i.e., maximum dose on panoramic radiology.

The role of the ADC value in the characterisation of renal carcinoma by diffusion-weighted MRI

The purpose of this study is to evaluate the role of diffusion-weighted imaging (DWI) in combination with T(1) and T(2) weighted MRI for the characterisation of renal carcinoma. The institutional review board approved the study protocols and waived informed consent from all of the patients. 47 patients (32 male and 15 female; age range, 21-85 years; median age, 65 years) who had suspected renal lesions on abdominal CT underwent MRI for further evaluation and characterisation of the lesions from April 2005 to August 2007 in our university hospital. A region of interest was drawn around the tumour area on apparent diffusion coefficient (ADC) maps. Final diagnosis was confirmed by histological examination of surgical specimens from all patients. The ADC value was significantly higher in renal cell carcinoma (RCC) than in transitional cell carcinoma (2.71+/-2.35 x 10(-3) mm(2) s(-1) vs 1.61+/-0.80 x 10(-3) mm(2) s(-1); p = 0.022). While analysing the histological subtypes of RCC, a significant difference in ADC values between clear cell carcinoma and non-clear cell carcinoma was found (1.59+/-0.55 x 10(-3) mm(2) s(-1) vs 6.72+/-1.85 x 10(-3) mm(2) s(-1); p = 0.0004). Similarly, ADC values of RCC revealed a significant difference between positive and negative metastatic lesions (1.06+/-0.38 x 10(-3) mm(2) s(-1) vs 3.02+/-2.44 x 10(-3) mm(2) s(-1); p = 0.0004), whereas intensity on T(1) and T(2) weighted imaging did not reach statistical significance. In conclusion, DWI has clinical value in the characterisation of renal carcinomas and could be applied in clinical practice for their management.

Relationship between age at onset and magnetic resonance image-defined hyperintensities in mood disorders

OBJECTIVES

To examine in patients with mood disorders the relationship of age at onset with the location and degree of MRI-defined brain hyperintensities.

METHOD

Fifty-two patients diagnosed as having mood disorders and 14 controls participated in the study. Brain MR images were analyzed according to semiquantitative ratings for the anatomical distribution and severity of T2-weighted hyperintensities. We compared these hyperintensities among the three age- and sex-matched groups of late-onset mood disorder patients (LOM), early-onset mood disorder patients (EOM), and controls. The time since the onset of disorder was significantly longer in the EOM than in the LOM group. We also conducted linear multiple regression analysis using the severity of hyperintensities as dependent variable to determine whether the clinical features correlate with vascular pathology.

RESULTS

As for deep white matter hyperintensity (DWMH), LOM exhibited higher ratings than EOM; as for brain areas, significant between-group differences were detected in the bilateral frontal areas and in the left parieto-occipital area. No significant difference was observed between EOM and controls. As for periventricular hyperintensity, there was no difference among the three groups. We obtained a significant regression model to predict DWMH ratings; age, number of ECTs, and LOM were selected as significant variables.

CONCLUSION

The present study suggests that the time since the onset of disorder does not affect the development of white matter lesions, but that white matter lesions are associated with late-onset mood disorders. The frontal areas and the left parieto-occipital area would be important for the development of late-onset mood disorders.

Brain metabolic changes associated with predispotion to onset of major depressive disorder and adjustment disorder in cancer patients--a preliminary PET study

OBJECTIVES

To explore neurobiological risk factors for major depressive disorder (MDD) and adjustment disorder in cancer patients by examining regional brain metabolism before psychiatric manifestation using positron emission tomography and by prospectively observing depressive and anxiety symptoms.

METHOD

Cancer patients who showed no psychiatric symptoms when they underwent 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) were followed up for one year using the Hospital Anxiety and Depression Scale (HADS). Fourteen patients who showed high HADS scores and 14 patients who showed low HADS scores were assessed by a psychiatrist 2 years after the PET scan and grouped into the deterioration group (n=10) and the no-change group (n=9). 18F-FDG PET images were analyzed to examine the difference in local brain glucose metabolism between the two groups.

RESULTS

The deterioration group showed a decreased glucose metabolism in the right medial frontal gyrus (BA6) and an increased glucose metabolism in the right posterior cingulate (BA29), right anterior cingulate (BA25), left subcallosal gyrus (BA25), and left caudate compared with the no-change group.

CONCLUSION

Cancer patients who later developed MDD or adjustment disorder showed regional brain metabolic changes. These regions may be associated with vulnerability to the onset of MDD or adjustment disorder in cancer patients.

Perfusion CT of breast carcinoma: arterial perfusion of nonscirrhous carcinoma was higher than that of scirrhous carcinoma

RATIONALE AND OBJECTIVES

Our goals were to apply perfusion CT technique to breast tumor and to evaluate the correlation between arterial perfusion value and other tumor characteristics.

MATERIALS AND METHODS

Thirty-one female patients with primary breast tumors were included in this study. A single-slice dynamic CT was performed after an intravenous bolus injection of contrast material (40 ml; 370 mg I/ml) at 8 ml/sec. The parameters were calculated on a pixel-by-pixel basis by using maximum slope method, and quantitative maps of arterial perfusion were created. Statistical correlation between tumor size, patient age, and perfusion were assessed. Differences in perfusion between scirrhous and nonscirrhous carcinoma were also assessed.

RESULTS

Perfusion CT images were successfully created for 24 patients (mean age, 55.9 years old; range, 36-85 years). In five patients, dynamic CT was not performed due to lack of visualization of the breast tumor on unenhanced CT. In two patients, reliable perfusion CT image could not be created because of motion artifact. The mean perfusion for 24 tumors was 33.1 +/- 16.9 ml/min/100 ml (mean +/- SD; range, 14-78), and the tumor perfusion did not correlate with patient's age or tumor size (21.0 +/- 10.2 mm; range, 10-45 mm). The mean perfusion of nonscirrhous carcinoma (45.8 ml/min/100 ml; n = 11) was higher than that of scirrhous carcinoma (22.7 ml/min/100 ml; n = 11; P < .001).

CONCLUSION

Determination of the perfusion of breast carcinoma is feasible by dynamic CT and can be performed during a routine CT study without much supplementary burden on the patient. There are differences in blood flow between scirrhous and nonscirrhous breast carcinoma, and further research is needed to determine the impact of this finding.

Air Embolism Detected During Computed Tomography Fluoroscopically Guided Transthoracic Needle Biopsy

Air embolism is a rare but potentially fatal complication of percutaneous needle biopsy of the lung. We report a case of cerebral air embolism which occurred during computed tomography (CT)-guided needle biopsy. Air entering the aorta is depicted on CT-fluoroscopy images of the procedure.

A Case of Gerstmann-Sträussler-Scheinker Syndrome

Gerstmann-Sträussler-Scheinker syndrome (GSS syndrome) is a rare hereditary disorder caused by prion protein gene mutation. We present the case of a 31-year-old man, whose signs and symptoms gradually progressed from loss of attention while driving at onset to headache, dysarthria, night sweat, fatigue, and dysgraphia. Diffusion-weighted imaging (DWI) of the brain after admission showed high signal intensities in the bilateral caudate nuclei, bilateral thalami, and cerebral cortices that suggested transmissible spongiform encephalopathy. The patient was diagnosed with GSS syndrome on genetic study. Magnetic resonance (MR) imaging of the entire period of sickbed showed gradually changing signal intensities and cerebral atrophy. We present a series of images and discuss the reasons for the abnormal intensities in GSS syndrome that vary among reported cases.

A case of testicular malignant lymphoma with extension to the epididymis and spermatic cord

Findings of magnetic resonance imaging (MRI) in a case of testicular lymphoma are presented. The tumor was lower intensity than the normal testis on T2-weighted images. Coronal images clearly showed the tumor extending to the spermatic cord. Compared with seminoma, lymphoma more often invades the epididymis and spermatic cord. MRI is a useful method for differentiating between testicular lymphoma and seminoma because it clearly shows tumor extension to the epididymis and spermatic cord.

Chronic expanding hematoma in the retroperitoneal space: a case report

A case of retroperitoneal chronic expanding hematoma complicated with hydronephrosis, which was difficult to diagnose preoperatively, is reported. The patient was a 70-year-old man. An 18 cm mass was detected in the right retroperitoneal space on abdominal CT screening. There were small calcifications in the periphery of the mass that were strongly enhanced in the delayed phase of dynamic CT. The mass involved the right ureter and iliopsoas muscle, resulting in severe hydronephrosis. The histological diagnosis was chronic expanding hematoma.

[Feasibility of CT attenuation values in the diagnosis of anemia]

PURPOSE

To verify the possible correlation between CT attenuation value and hemoglobin (Hb).

MATERIALS AND METHODS

CT attenuation was evaluated in 113 CT studies. Anemia was defined as an Hb level less than 14 g/dl in males and less than 12 g/dl in females. Hb was compared visually by grading (Grade 1: cardiac muscle density much higher than lumen, Grade 2: cardiac muscle density higher than lumen, Grade 3: cardiac muscle density equal to lumen), and with HU of CT attenuation on unpaired t-test (p<0.01). Correlations were calculated using the linear regression method.

RESULTS

Hb of less than 6 g/dl was found to be Grade 1, while that over 12 g/dl was considered Grade 3 on visual grading. The attenuation numbers of subjects with anemia yielded low values, whereas those of normal subjects were higher. There were significant differences between subjects with anemia and normal subjects (p<0.01). HU versus hemoglobin showed a linear increase, with a correlation coefficient of 0.76.

CONCLUSIONS

This simple, readily available information may provide a valuable adjunct in the interpretation of CT examinations.

[Contrast-enhanced MR venography of the head using magnetization prepared rapid gradient echo imaging: comparison between head and body radiofrequency transmitter coil systems]

PURPOSE

To evaluate the image quality and vascular selectivity of MR venography of the head using an MP-RAGE technique when obtained with a body radiofrequency transmitter coil system.

MATERIALS AND METHODS

A total of 24 patients were imaged with a head or body RF transmission system. Subtraction MRA was processed with 0.1 mmol Gd-DTPA administration, and signal-to-noise ratios of the vascular system were measured. Venous demonstration and selectivity were also assessed.

RESULTS

MP-RAGE MR venography with a body transmission system showed almost the same signal intensity for the venous and arterial systems, resulting in nonspecific vascular demonstration, while the head transmission system showed semi-selective venograms owing to inflow-induced high signal on precontrast images. However, MRA with a body transmission system provided a 1.5- to 2.5-fold higher signal-to-noise ratios based on higher gradient performance and excellent demonstration of the head veins, especially those below the skull base.

CONCLUSION

Although selective venography was difficult, MRA with a body transmission coil provided excellent vascular images of the brain.

[Dual-phase chemical-shift imaging in the detection of diffuse bone metastasis]

Preliminary studies were performed to evaluate the usefulness of lumbar bone marrow MRI using the dual chemical-shift GRE sequence in the detection of diffuse bone metastasis. Two GRE images (TE = 2.3 msec and 4.6 msec) were obtained, and SIR was calculated. SIR was designated as the ratio of in-phase to out-of-phase signal intensity. Among 45 patients with suspicious lumbar bone metastases, diffuse bone metastases were present in 7. Mean SIRs were compared by unpaired t-test. SIRs of diffuse bone metastases had significantly higher signal intensities than those of non-diffuse bone metastases of vertebrae (p < 0.01).

Angiosarcoma of the breast: report of a case and its findings of MRI

A 67-year-old woman with angiosarcoma of the left breast is presented. Physical findings showed a hard mass in the left breast with skin discoloration and erythema. Mammography showed a high density shadow in the mass without microcalcification and spicula. On ultrasonography, a hypoechoic mass with an ill-defined boundary was detected. On MRI, the tumor had low signal intensity on T1-weighted images, and higher signal intensity on T2-weighted images. MRI with Gd-DTPA images showed higher signal intensity on T1-weighted images with relatively lower intensity in the central area of the tumor. The artery supplying the tumor derived from the left inner thoracic artery and was visualized on three-dimensional dynamic MRI angiography. Initially misdiagnosed as inflammatory breast cancer, an arterial injection of CPA (100 mg) and 5-FU (500 mg) had been performed preoperatively. The definitive diagnosis of angiosarcoma was established by intraoperative frozen section examination. She underwent modified radical mastectomy and is now free of recurrence. This case emphasizes the difficulties in the clinical diagnosis of angiosarcoma of the breast.

Histopathological analysis of a bladder cancer stalk observed on MRI

Papillary transitional cell carcinoma of the bladder has a loose connective tissue stalk. For staging of bladder cancer on magnetic resonance imaging (MRI), it is important to clearly separate the cancer from the bladder wall. It is possible to distinguish a stalk from the cancer by the difference of intensity on the using MRI. Sixteen stalks of 20 polypoid bladder tumors on any of the T(2)W(I), dynamic images and delayed enhanced images were demonstrated. Most of the stalks show lower signal intensity than the tumors on T(2)W(I), less enhancement on dynamic images and stronger enhancement on delayed enhanced images. The stalk consisted of fibrous connective tissue, capillary blood vessels, inflammatory cell infiltration and edema. This stalk extended from the bladder wall to the center of the tumor. Some of the superficial muscular bundles were pulled into the stalk. These histopathological findings were compatible with the patterns of signal intensities on MRI. The identification of the stalk of a polypoid tumor may be an important observation to exclude bladder wall invasion by tumor.

[Table-moving contrast-enhanced MR angiography of abdominal aortic aneurysm]

Table-moving contrast-enhanced MR angiography (MRA) was performed in 14 cases of abdominal aortic aneurysm to evaluate its clinical usefulness. In all cases, aneurysms were clearly demonstrated and image quality was clinically acceptable. Findings of reconstructed MRA were highly consistent with those of DSA, and thrombosed areas were confirmed on source images. Main aortic branches including renal arteries, common iliac arteries, and internal and external iliac arteries were readily identified on reconstructed MRA and/or source images. Additional findings such as thoracic aortic aneurysm (n = 1), common iliac aneurysm (n = 6), external iliac aneurysm (n = 1), internal iliac aneurysm (n = 1), femoral arterial obstruction (n = 2), and femoral arterial stenosis (n = 4) were also detected. Although table-moving MRA may have disadvantages like reduced blood signal and limited spatial resolution compared with the conventional contrast-enhanced technique, the images that were obtained provided sufficient contrast and resolution for preoperative evaluation. Because abdominal aortic aneurysm is accompanied by various arterial abnormalities in many of the large arteries, table-moving MRA was considered a suitable technique for comprehensive assessment.

[Bone marrow survey by MRI using a table-moving technique]

The bone marrow of the whole body was imaged by MRI in five normal volunteers. The fast short tau inversion recovery (STIR) sequence and sequential imaging using a moving-table system made sagittal and coronal whole body marrow imaging possible within an examination time of 10 minutes. The images obtained showed high resolution and reflected normal red and yellow marrow distribution in all subjects. Additional abnormalities including humeral bone cyst, hepatic cavernous hemangiomas, and maxillary retention cyst were detected. Fast STIR with the table-moving technique was considered a suitable method for rapid bone marrow survey.

A case of extrahepatic portal vein aneurysm with massive thrombosis: diagnosis with reconstruction images from helical CT scans

A patient with extrahepatic portal vein aneurysm with massive thrombosis, congenital in nature, is reported. Reconstructed images using curved reformation software and three-dimensional images from helical CT were useful to delineate the shape of the portal vein aneurysm and extension of the thrombi.