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ABSTRACT: The pull-through technique is an interventional radiological procedure used when an occluded lesion cannot be traversed from one direction. To pass the lesion, a long guidewire is traversed from the opposite side and pulled through the ipsilateral sheath using a snare wire. The present report describes a case of severe superior vena cava syndrome treated by stent placement using a pull-through technique with pincer tactics. We successfully placed a stent in the occluded right internal jugular vein to the superior vena cava using a bilateral approach by snaring a guidewire in the right subclavian vein.
Annals of Vascular Surgery 01/2012; 26(3):421.e11-5. · 1.03 Impact Factor
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ABSTRACT: Liver abscesses occurring just below the diaphragm can penetrate or perforate the thoracic cavity, resulting in lung abscess or pyothorax. Although surgical or percutaneous transpleural drainage is often required in such cases, the latter approach has some risks, including hemothorax and bronchopleural fistula formation when the cavity is surrounded by normal lung parenchyma. The present report describes a treatment technique of percutaneous transhepatic drainage through the diaphragmatic fistula to avoid the risks of a transpulmonary approach in a case of lung abscess caused by a penetrating liver abscess.
Japanese journal of radiology 11/2011; 29(9):663-6. · 0.65 Impact Factor
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ABSTRACT: To evaluate whether perfusion fraction (PF) calculated with diffusion-weighted magnetic resonance imaging (MRI) predicts the presence of blood supply in ovarian masses.
PFs of 92 ovarian lesions in 53 patients administered gadolinium were retrospectively calculated with diffusion-weighted images at b-values of 0, 500, and 1000 sec/mm(2). PFs were compared between ovarian lesions, except for fat, with (n = 21) or without contrast enhancement (n = 57), using Student's t-test and receiver operating characteristics (ROC) curve analysis. Lesion enhancement rates of contrast-enhanced images at 30 and 180 seconds after gadolinium injection (ER(30sec) and ER(180sec)) and PFs were compared using Pearson's correlation coefficient.
PFs of the lesions with contrast enhancement were significantly higher than those without contrast enhancement (0.22 ± 0.09 and 0.02 ± 0.08, respectively, P < 0.0001). The ROC curve identified the best cutoff point for PF at 0.135 (95.2% sensitivity and 94.7% specificity) as a predictor of the contrast enhancement effect. The area under the ROC curve was 0.984. PF correlated moderately with ER(30sec) (0.62, y = 0.13x + 0.04, P < 0.0001) and ER(180sec) (0.74, y = 0.13x + 0.03, P < 0.0001).
PF calculated with diffusion-weighted images can potentially predict blood supply in ovarian masses.
Journal of Magnetic Resonance Imaging 09/2011; 34(5):1131-6. · 2.70 Impact Factor
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ABSTRACT: To compare the image qualities of unenhanced electrocardiographically (ECG)-gated fast spin-echo magnetic resonance digital subtraction angiography (MRDSA) using a short echo-spacing three-dimensional (3D) sequence, known as sampling perfection with application-optimized contrasts using different flip angle evolutions (SPACE), and the conventional half-Fourier single-shot turbo spin-echo (HASTE) sequence.
Unenhanced ECG-gated MRDSA using SPACE and HASTE of the femoral arteries were prospectively acquired in 13 healthy volunteers at 1.5 Tesla (T) MRI. Sequential frontal maximum-intensity-projection images produced by subtracting each of 10 systolic images from a diastolic image were evaluated quantitatively using paired t-test and qualitatively by two blinded radiologists using the Mann-Whitney U-test.
Quantitatively, relative contrast against the background, contour sharpness index, and slope of the sequential signal changes of the superficial femoral artery of MRDSA using SPACE were significantly better than those of HASTE (P = 0.005, P = 0.001, and P < 0.0001, respectively). Qualitatively, the overall subjective image quality and sequential appearance changes of MRDSA using SPACE were significantly better than those of HASTE (P < 0.0001 and P < 0.0001, respectively).
Unenhanced ECG-gated fast spin-echo MRDSA using SPACE produces increments in signal intensity, which reflect arterial pulse wave transmission, more clearly than the conventional HASTE sequence.
Journal of Magnetic Resonance Imaging 07/2011; 34(1):157-64. · 2.70 Impact Factor
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ABSTRACT: We report a case of subarachnoid hemorrhage with a ruptured aneurysm in the anterior communicating artery. On multiphase dynamic contrast-enhanced four-dimensional computed tomography angiography (4D CTA), we observed active bleeding from the aneurysm that manifested over time with a corkscrew-like, spindle-like, and lobulated appearance and nebulous enhancement, characteristics reported only individually previously. The volume data for 4D CTA is easy to obtain with newly developed multidetector-row computed tomography, and 4D CTA can be used for evaluating anatomical aspects, hemodynamics, and treatment selection in cases of a ruptured cerebral aneurysm.
Japanese journal of radiology 06/2011; 29(5):348-52. · 0.65 Impact Factor
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ABSTRACT: We investigated the utility of computed tomographic (CT) perfusion (CTP) with 64-row multi-detector row CT (MDCT) to diagnose acute infarction and ischemic penumbra. We reviewed 58 clinical cases with acute ischemic stroke with CTP, compared the size of the area with long mean transit time (MTT) to that with abnormal intensity in magnetic resonance (MR) diffusion-weighted imaging (DWI) to diagnose penumbra, and compared the size of the area with reduced cerebral blood volume (CBV) in CTP to that in MR DWI to evaluate sensitivity for infarction. The total sensitivity of MTT to acute ischemic lesions was 81% (47/58). Sensitivity of MTT to segmental lesions was 100% (42/42) and for spot and focal lesions, 31% (5/16). In 13 patients, penumbra was diagnosed as lesions mismatched between MTT in CTP and MR DWI. When we regarded a lesion with decreased CBV as infarction, the sensitivity of CBV to segmental lesions was 85% (11/13), and the sensitivity to small infarction was 14% (4/28). Use of 64-row MDCT improves coverage and radiation exposure in head CTP. The combination of plain CT, CT angiography, and CTP with MDCT can demonstrate all segmental ischemic lesions and most large segmental infarctions, and their combined application is useful in considering indication and contraindication for thrombolysis. The problem of low sensitivity for small lesions remains, and MR DWI may be required to assess small infarctions when findings from combined plain CT, CT angiography, and CTP are negative in patients with suspected acute brain stroke.
Emergency Radiology 04/2011; 18(2):95-101.
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ABSTRACT: The aim of this prospective study was to assess the reliability of a rapid, handy, point-of-care whole blood creatinine meter (PCM) in patients who were scheduled to undergo contrast-enhanced computed tomography (CT) or magnetic resonance imaging (MRI).
Among patients scheduled to undergo contrast-enhanced CT or MRI examinations, 113 patients who did not have creatinine data from the prescribed intervals before the examination day (in principle, 90 days for scheduled outpatients and 7 days for inpatients and urgent patients) were included. The estimated glomerular filtration rate (eGFR) was calculated using the creatinine values measured with the PCM and those from central laboratory measurements (LAB). The two eGFR values were compared statistically with the paired t-test, Pearson's correlation coefficient, and the Bland-Altman analysis.
The mean eGFR measured with the PCM was slightly higher than the LAB value (81.2 ± 24.6 vs. 70.2 ± 19.7 ml/min/1.73 m(2), P < 0.0001). They were well correlated (r = 0.74, y = 0.92x + 16.9, P < 0.0001). Bland-Altman plots (mean difference was 11.0 ml/min/1.73 m(2); limits of agreement were -22.4 to +44.4 ml/min/1.73 m(2)) showed a moderate agreement with some degree of dispersion.
The PCM can rapidly assess renal function using a small amount of blood almost equally to that of determined in the laboratory, which may help reduce the risk of contrast material-induced complications.
Japanese journal of radiology 04/2011; 29(3):187-93. · 0.65 Impact Factor
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ABSTRACT: To elucidate the causes of aliasing artifacts with the BLADE technique and clarify the effective suppression methods.
We separately observed the aliasing artifacts of BLADE from features inside and then outside the defined field-of-view (FOV) using phantom studies. The effectiveness of suppressing them with phase oversampling (POS) and presaturation pulses (SAT) was evaluated. Finally, our observations were confirmed for a healthy volunteer.
Characteristic aliasing artifacts were observed from both inside and outside the FOV. Those from inside the FOV were sufficiently suppressed by using a POS of 25%, considering the acquisition time prolongation. Those from outside the FOV were nearly suppressed using SAT outside the FOV without selecting needless receiver coils. Aliasing artifacts on the coronal images of the head and neck with a healthy volunteer were completely suppressed by a combination of using a POS of 25% and using SAT on all four sides outside the FOV.
The characteristic aliasing artifacts of BLADE are caused from both inside and outside the defined FOV. They can be effectively suppressed by a combination of using a POS of 25% and using SAT on all four sides outside the FOV.
Journal of Magnetic Resonance Imaging 02/2011; 33(2):432-40. · 2.70 Impact Factor
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ABSTRACT: Our patient was diagnosed with acute subarachnoid hemorrhage on plain head computed tomography (CT). Multiphase dynamic contrast-enhanced CT angiography on a 64-row multidetector scanner revealed a large aneurysm in the left middle cerebral artery that was not detected on conventional helical CT angiography. We believed that increased intracranial pressure and rough thrombus within the aneurysm delayed its peak enhancement. Our case demonstrates the diagnostic utility of four-dimensional CT with multiphase volume data in cases of lesions with delayed enhancement.
Japanese journal of radiology 11/2010; 28(9):680-3. · 0.65 Impact Factor
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ABSTRACT: We aimed to evaluate flow patterns in the superior vena cava (SVC) and azygos vein confluence with cine phase-contrast magnetic resonance imaging with consideration for the role played by the azygos arch valves.
Two-dimensional cine phase-contrast magnetic resonance images of the SVC and azygos vein confluence were prospectively acquired in 10 healthy volunteers. Flow directions during the cardiac cycle were evaluated quantitatively using sequential flow profile graphs obtained from each orthogonal image and affirmed visually by two radiologists from the oblique sagittal cine images.
Although the blood in the SVC and azygos vein confluence had an afferent flow during the systolic phase, a slight temporal efferent flow during the diastolic phase was quantitatively observed in all cases. Flow in the SVC can also be confirmed visually. The average velocity, average maximum afferent velocity during the systolic phase and average maximum efferent velocity during the diastolic phase of the SVC were 8.7 ± 2.4, 19.9 ± 3.7 and -1.0 ± 3.2 cm/s, respectively; for the azygos vein confluence, these values were 2.2 ± 1.5, 7.1 ± 2.6 and -1.5 ± 1.1 cm/s, respectively.
We verified that a slight temporal efferent flow exists in the SVC and azygos vein confluence during the diastolic phase, which suggests that the usual role of the azygos arch valves is to prevent this physiological retrograde flow.
Magnetic Resonance Imaging 11/2010; 28(9):1306-10. · 1.99 Impact Factor
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Haruhiko Machida,
Yoshiaki Komori,
Eiko Ueno,
Yun Shen,
Masami Hirata,
Shinya Kojima,
Munekuni Sato,
Takeshi Okazaki,
Ai Masukawa, Satoru Morita,
Kazufumi Suzuki
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ABSTRACT: We compared the accuracy of magnetic resonance imaging (MRI) measurements of pulsatile flow velocity in a small tube phantom using different spatial factors versus those obtained by intraluminal Doppler guidewire examination (as reference).
We generated pulsatile flow velocities averaging about 20-290 cm/sec in a tube of 4 mm diameter; we performed phase-contrast cine MRI on pixels measuring 1.00(2)-2.50(2) mm(2). We quantified spatial peak flow velocities of a single pixel and a cluster of five pixels and spatial mean velocities within regions of interest enclosing the entire lumen in the phantom's cross-section. Finally, we compared the measurements of temporally mean and maximum flow velocity with the Doppler measurements.
Linear correlation was excellent between both measurements of spatial peak flow velocities in one pixel. The highest spatial resolution using spatial peak flow velocities of a single pixel allowed the most accurate MRI measurements of both temporally mean and maximum pulsatile flow velocity (r = 0.97 and 0.99, respectively: MRI measurement = 0.95x + 8.9 and 0.88x + 24.0 cm/s, respectively). Otherwise, MRI measurements were significantly underestimated at lower spatial resolutions.
High spatial resolution allowed accurate MRI measurement of temporally mean and maximum pulsatile flow velocity at spatial peak velocities of one pixel.
Japanese journal of radiology 10/2010; 28(8):571-7. · 0.65 Impact Factor
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ABSTRACT: The aim of this study was to compare prospectively the image quality of magnetic resonance cholangiopancreatography (MRCP) using manganese chloride tetrahydrate (Bothdel Oral Solution 10) (MCT), a new negative oral contrast agent; ferric ammonium citrate (FerriSeltz powder 20%) (FAC); and no agent.
MRCP images (TE 970 ms) of patients administered MCT (n = 19) or FAC (n = 20) at random, and 18 patients without an agent were evaluated. The subjective image quality of the overall, extrahepatic bile duct, and pancreatic duct and the degree of elimination of gastrointestinal fluid scored by two radiologists blinded to information regarding the agent were compared using Mann-Whitney's U-test.
The degrees of elimination of gastroduodenal fluid of MCT and FAC were significantly better than those without an agent (P < 0.01 and P < 0.01). The subjective image quality of MCT of the overall and extrahepatic bile duct were significantly better, although no significant differences for FAC were observed compared with those without an agent (P < 0.01 and P = 0.21, P = 0.02 and P = 0.16). There were no significant differences for the pancreatic duct (P = 0.12 and P = 0.19), nor were there any significant differences in the evaluations between MCT and FAC (P = 0.19-0.98).
MCT has shown performance comparable to that of conventional FAC in terms of pancreatic and biliary depiction and safety.
Japanese journal of radiology 02/2010; 28(2):117-22. · 0.65 Impact Factor
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Haruhiko Machida,
Shinichi Nunoda,
Kiyotaka Okajima,
Kazunobu Shitakura,
Akihiko Sekikawa,
Kuniaki Suwa,
Tomoko Kikuchi,
Shun Nakajima,
Miwa Hattammaru,
Reiko Hozo,
Tetsuya Mitsuhashi,
Yutaka Kubo,
Kuniaki Otsuka,
Masami Hirata,
Shinya Kojima,
Ai Masukawa, Satoru Morita,
Kazufumi Suzuki,
Eiko Ueno
Journal of Cardiovascular Magnetic Resonance. 01/2010;
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ABSTRACT: When a vascular disease is suspected, the focus is usually on morphologic features seen at contrast material-enhanced multidetector computed tomography (CT). However, unenhanced CT also plays an important role in revealing so-called hyperattenuating signs, which represent a slight increase in the focal attenuation of a vessel. Hyperattenuating signs are occasionally observed when an acute clot has formed in a vessel and can be seen in various vascular diseases, including acute arterial occlusion, acute arterial dissection, aneurysm rupture, and acute venous thrombosis. The attenuation of these signs tends to increase because the concentration of hemoglobin increases as water content decreases. Hyperattenuating signs are a transient phenomenon, as the attenuation gradually decreases. Therefore, they can serve as unique findings indicating an acute state. Although hyperattenuating signs are not well understood, recognition of these signs is important because they can help reveal serious acute vascular diseases even at unenhanced CT.
Radiographics 01/2010; 30(1):111-25. · 2.85 Impact Factor
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ABSTRACT: To compare three-dimensional segmented true fast imaging with steady-state precession magnetic resonance cholangiopancreatography (3D-trueFISP-MRCP) to conventional MRCP sequences with an oral negative contrast agent for diagnosing juxtapapillary diverticulum.
A total of 42 patients with (n = 21) and without (n = 21) juxtapapillary diverticulum confirmed by endoscopic retrograde cholangiopancreatography (ERCP) were evaluated. Three MRCP sequences, 3D-trueFISP-MRCP, two-dimensional rapid acquisition with relaxation enhancement MRCP (2D-RARE-MRCP), and 3D T(2)-weighted turbo spin-echo MRCP (3D-TSE-MRCP), obtained after administering an oral negative contrast agent (FerriSeltz; Otsuka Pharmaceutical, Tokushima, Japan) were compared. Two radiologists independently and blindly interpreted the presence or absence of juxtapapillary diverticulum and its positional relationship against the papilla. The detectability of juxtapapillary diverticulum of each sequence as decided by consensus was then compared. Kappa statistics were used to measure interobserver agreement of the classifications.
The sensitivity, specificity, and accuracy for detecting juxtapapillary diverticulum of 3D-trueFISPMRCP (61.9%, 85.7%, and 73.8%) were substantively higher than those of 2D-RARE-MRCP (0.0%, 100%, and 50.0%) and 3D-TSE-MRCP (9.5%, 100%, and 54.8%). Interobserver agreement of the position of juxtapapillary diverticulum by 3D-trueFISP-MRCP was good (kappa = 0.55).
3D-trueFISP-MRCP can define juxtapapillary diverticulum even with an oral negative contrast agent, whereas conventional MRCP sequences cannot.
Japanese journal of radiology 12/2009; 27(10):423-9. · 0.65 Impact Factor
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ABSTRACT: We examined the spatial factors influencing magnetic resonance (MR) flow velocity measurements in a small tube phantom and used the same measurements obtained with an intraluminal Doppler guidewire as reference.
We generated constant flow velocities from approximately 40 to 370 cm/s in a tube 4 mm in diameter. We then performed segmented k-space, phase-contrast cine-MR imaging to quantify spatial peak flow velocities of one pixel and of five adjacent pixels as well as spatial mean velocities within regions of interest in a cross section of the phantom. Pixel dimensions ranged from 1.00 x 1.00 mm to 2.50 x 2.50 mm. We compared the MR measurements with the temporally averaged Doppler spectral peak velocities.
For one pixel (r > 0.99: MR flow velocity for pixel dimension 1.00 x 1.00 mm = 1.03x + 9.8 cm/s), the linear correlation was excellent between flow velocities by MR and Doppler guidewire methods. However, for the five adjacent pixels, MR measurements were significantly underestimated using pixels 1.25 x 1.25 mm to 2.50 x 2.50 mm and for mean velocities for all pixel dimensions.
Relatively high spatial resolution allows accurate MR measurement of constant flow velocity in a small tube at spatial peak velocities for one pixel.
Japanese journal of radiology 11/2009; 27(9):335-41. · 0.65 Impact Factor
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ABSTRACT: The purpose of this clinical note is to describe the feasibility of using diffusion-weighted imaging for diagnosing placental invasion with a case of placenta increta and six cases without it. Diffusion-weighted imaging (DWI) at a b-value of 1000 sec/mm(2) can clearly define the border between the placenta and myometrium because only the placenta shows very high signal intensity. The corresponding image at a b-value of 0 sec/mm(2) shows the myometrium with high signal intensity compared with the surrounding fat. Therefore, fusion of the two images can be used additionally to visualize thickness of the myometrium. As a result, DWI can be used to visualize the focal thinning of the myometrium caused by placenta increta, which has been difficult to diagnose on conventional magnetic resonance imaging sequences without contrast enhancement. However, the use of DWI for placental invasion should be determined following careful consideration of its risks and benefits, as fetus safety has not been established.
Journal of Magnetic Resonance Imaging 09/2009; 30(3):666-71. · 2.70 Impact Factor
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PhD Satoru Morita MD,
PhD Eiko Ueno MD,
PhD Mikihiko Fujimura MD,
Mitsue Muraoka MD,
Koichiro Takagi MD,
Mariko Fujibayashi MD, Satoru Morita,
Eiko Ueno,
Mikihiko Fujimura,
Mitsue Muraoka,
Koichiro Takagi,
Mariko Fujibayashi
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ABSTRACT: The purpose of this clinical note is to describe the feasibility of using diffusion-weighted imaging for diagnosing placental invasion with a case of placenta increta and six cases without it. Diffusion-weighted imaging (DWI) at a b-value of 1000 sec/mm2 can clearly define the border between the placenta and myometrium because only the placenta shows very high signal intensity. The corresponding image at a b-value of 0 sec/mm2 shows the myometrium with high signal intensity compared with the surrounding fat. Therefore, fusion of the two images can be used additionally to visualize thickness of the myometrium. As a result, DWI can be used to visualize the focal thinning of the myometrium caused by placenta increta, which has been difficult to diagnose on conventional magnetic resonance imaging sequences without contrast enhancement. However, the use of DWI for placental invasion should be determined following careful consideration of its risks and benefits, as fetus safety has not been established. J. Magn. Reson. Imaging 2009;30:666–671. © 2009 Wiley-Liss, Inc.
Journal of Magnetic Resonance Imaging 08/2009; 30(3):666 - 671. · 2.70 Impact Factor
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ABSTRACT: To compare volume-rendering (VR) and maximum-intensity-projection (MIP) of three-dimensional T2-weighted turbo spin-echo magnetic resonance cholangiopancreatography using a free-breathing navigator-triggered prospective acquisition correction (3D-TSE-PACE-MRCP) to define biliary anatomies.
VR and MIP images of 3D-TSE-PACE-MRCP for 102 patients were retrospectively evaluated. Interpretation of cystic duct variation and biliary branching patterns of each image were recorded independently by two radiologists in a blinded fashion. Interpretation confidence on a five-point scale was compared using the Wilcoxon signed-rank test. The McNemar test was used to compare the accuracies of each reformation with the reference standard obtained by consensus interpretation of both the images and source images.
The reference standard identified all biliary bifurcations and 95 of 102 cystic duct confluences (93.1%). VR findings agreed with the reference standard findings more often than MIP with regard to cystic duct variation (94 [92.2%] vs. 76 [74.5%], P<0.01) while there was no significant difference for biliary branching patterns (99 [97.1%] vs. 92 [90.2%], P=0.092). The mean confidence score was significantly higher with VR than MIP with regard to both cystic duct variation and biliary branching patterns (3.7 vs. 2.4; P<0.01; 4.1 vs. 3.3; P<0.01).
VR reformation of 3D-TSE-PACE-MRCP defines biliary anatomies more accurately than MIP.
Journal of Magnetic Resonance Imaging 03/2009; 29(3):601-6. · 2.70 Impact Factor
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ABSTRACT: We prospectively compared the quality of images obtained by navigator setting on the left and right diaphragm on whole-heart coronary magnetic resonance angiography (WHCMRA).
In 10 healthy volunteers, we performed free-breathing, 3-dimensional segmented true fast imaging with steady-state precession (trueFISP) WHCMRA by setting the navigator on the left and right diaphragm in random order. For the left diaphragm, we set the navigator outside the scope of the heart to avoid the influence on coronary arteries. We compared image acquisition time and visible length of coronary arteries using paired t-test and subjective image quality on a 4-point scale (1, poor; 4, excellent) using Wilcoxon signed-rank test.
Mean overall subjective image quality was significantly better in the left diaphragm than the right (3.3+/-0.7 versus 2.9+/-0.9, P=0.02). Mean overall visible length of the coronary arteries was significantly better in the left diaphragm than the right (115.4+/-31.1 vs. 112.6+/-29.9 mm, P=0.02). Mean acquisition time between the left and right diaphragm was not significantly different (15.6+/-5.0 versus 16.0+/-5.7 min, P=0.79).
In this small group of healthy volunteers, navigator setting for WHCMRA was superior on the left diaphragm than the right; however, feasibility of the technique requires additional consideration in a larger group of actual patients.
Magnetic Resonance in Medical Sciences 02/2009; 8(1):17-21. · 0.97 Impact Factor
