Internal Structures of the Globus Pallidus in Patients with Parkinson's Disease: Evaluation with Phase Difference-enhanced Imaging.

PURPOSE: The medial medullary lamina (MML) separates the medial globus pallidus (GPm) from the lateral. The aim of this study was to assess the changes in appearance of MML related to age using the phase difference-enhanced (PADRE) imaging and to determine whether PADRE can depict the MML in the patients with Parkinson's disease (PD). MATERIALS AND METHODS: We enrolled 20 patients with PD and 50 normal control subjects (NC). First, for the visualization of the MML in the NC, we compared the PADRE, susceptibility-weighted imaging (SWI)-like images and T2 weighted imaging (WI) by using multiple comparison. The grading methods are as follows: grade 1; MML was not delineated, grade 2; less than half of MML was delineated, grade 3; more than half of MML was delineated and grade 4; whole MML was clearly delineated. We determined grade 3 and 4 as good depiction, delineating the GPm. Then, we evaluated patients with PD using the same method. RESULTS: In NC, the delineation of MML was good in 84% of cases on PADRE, but only 34% of cases showed a good depiction on SWI-like images (average grading score 3.31 vs 2.11, P < 0.05). No MML was delineated in all cases on T2 WI. Although younger subjects tended to show whole MML clearly, a part of MML tends to be obscured with age on PADRE. In patients with PD the depiction of MML on PADRE was also good in 90% of cases. CONCLUSION: The PADRE technique facilitates the depiction of the MML within globus pallidus (GP) on a broad range of age NC and patients with PD and it is superior to SWI-like images and T2 WI.

Signal intensity of superficial white matter on phase difference enhanced imaging as a landmark of the perirolandic cortex.

Background The superficial white matter (SWM), which fills the space between the deep white matter and the cortex, has not been well characterized. Purpose To determine whether the assessment of the relative signal intensity (SI) of the SWM in the precentral and postcentral gyri on phase difference enhanced (PADRE) images contributes in establishing anatomical landmark. Material and Methods The study population consisted of 43 normal subjects (28 women, 15 men; mean age, 52.9 years; age range, 22-90 years). By the consensus of two observers, the precentral gyri, postcentral gyri, and superior frontal cortex (SFC) were identified based on the established anatomical methods. The SI of the SWM in the precentral and postcentral gyri on PADRE images was divided into three grades in comparison with that of the SFC: Grade I, isointense; Grade II, slightly hypointense; and Grade III, markedly hypointense. Results The SWM in the precentral and postcentral gyri showed hypointensity on PADRE images. In the SI analyses of the PADRE images, the Grade I, Grade II, and Grade III appearances were found in one (1%), 20 (23%), and 65 (76%) of the 86 precentral gyri (43 subjects), respectively, and in one (1%), 23 (27%), and 62 (72%) of the 86 postcentral gyri, respectively. Conclusion On PADRE images, the perirolandic SWM showed hypointensity compared to other cerebral cortices, which probably reflects differences in the concentrations of the nerve fibers, as well as the higher myelin content. PADRE may be useful for the identification of the central sulcus by assessing the SI of the SWM.

Interimager variability in ADC measurement of the human brain.

PURPOSE: Routine clinical practice involves the application of diverse scanning parameters that can affect apparent diffusion coefficient (ADC) values. We evaluated interimager variability in ADC values with respect to their potential effect in clinical applications. METHODS: In 7 healthy volunteers, we obtained diffusion-weighted (DW) images using routine clinical parameters and 1.5- (n = 9) and 3-tesla (n = 3) magnetic resonance (MR) imagers from 5 different vendors, performing 84 MR imaging studies. To evaluate the differences in ADC values among the imagers, vendors, and magnetic field strengths, we measured the mean pixel values of the frontal white matter and thalamus (gray matter) in both cerebral hemispheres of the 7 volunteers and used repeated-measures analysis of variance for multiple comparisons. RESULTS: The laterality of ADC values in the bilateral structures ranged from one to 3% for the 12 imagers. Although the relative difference in ADC values of white matter was 7% for scanners yielding the highest and lowest mean ADC values (P < 0.01), it was within 2 to 4% for instruments from the same vendors. For gray matter, the interimager difference was 4 to 12%, even among the same vendors (P < 0.05). Among the 3T imagers, the difference for white and gray matter was approximately 3%. CONCLUSIONS: There were significant interimager differences in ADC values, especially with respect to gray matter. Taking into consideration the existing laterality, however, the differences among our 3T imagers may be acceptable despite the use of diverse scanning parameters. In routine clinical practice, the existing variability must be considered imager by imager.

Diagnosis of intracranial hemorrhagic lesions: comparison between 3D-SWAN (3D T2*-weighted imaging with multi-echo acquisition) and 2D-T2*-weighted imaging.

BACKGROUND: 3D-susceptibility-weighted angiography (SWAN) can produce high-resolution images that yield excellent susceptibility-weighted contrast at a relatively short acquisition time. PURPOSE: To compare SWAN- and 2D-T2*-weighted gradient-echo images (T2*-WI) for their sensitivity in the depiction of cerebral hemorrhagic lesions. MATERIAL AND METHODS: We subjected 75 patients with suspected cerebral hemorrhagic lesions to SWAN and T2*-WI at 3T. We first measured the contrast-to-noise ratio (CNR) using an agar phantom that contained different concentrations of superparamagnetic iron oxide (SPIO). The acquisition time for SWAN and T2*-WI was similar (182 vs. 196 s). Neuroradiologists compared the two imaging methods for lesion detectability and conspicuity. RESULTS: The CNR of the phantom was higher on SWAN images. Of the 75 patients, 50 were found to have a total of 278 cerebral hemorrhagic lesions (microbleeds, n = 229 [82.4%]; intracerebral hemorrhage, n = 18 [6.5%]; superficial siderosis, n = 13 [4.7%]; axonal injuries, n = 8 [2.9%]; subarachnoid hemorrhage [SAH] or brain contusion, n = 3 each [1.0%]; subdural hematoma, n = 2 [0.7%]; cavernous hemangioma or dural arterteriovenous fistula, n = 1 each [0.4%]). In none of the lesions was the SWAN sequence inferior to T2*-WI with respect to lesion detectability and conspicuity. In fact, SWAN yielded better lesion conspicuity in patients with superficial siderosis and SAH: it detected significantly more lesions than T2*-WI (P < 0.01) and it was particularly useful for the detection of microbleeds and lesions near the skull base. CONCLUSION: SWAN is equal or superior to standard T2*-WI for the diagnosis of various cerebral hemorrhagic lesions. Because its acquisition time is reasonable it may replace T2*-WI.

Parkinson's disease: diagnostic potential of high-resolution phase difference enhanced MR imaging at 3 T.

OBJECTIVES: To determine whether it is possible to diagnose patients with Parkinson's disease (PD) on an individual basis using magnetic resonance imaging with phase difference enhanced imaging (PADRE). METHODS: PADRE delineated the crural fibres as a layer of low signal intensity and the substantia nigra as a layer of medium signal intensity in a healthy volunteer, and showed a clear boundary between the crural fibres and the substantia nigra (BCS). Twenty-four PD patients and 24 control subjects were enrolled. Contrast ratios between the substantia nigra and occipital white matter were calculated, and two radiologists independently reviewed the PADRE findings regarding BCS obscuration. RESULTS: Mean contrast ratio in PD patients was significantly higher than in control subjects (0.56 vs 0.39, P < 0.01). The BCS on PADRE was obscured significantly more frequently in any subgroups with PD patients compared with control subjects (P < 0.01). The observation of BCS obscuration had a sensitivity, specificity and accuracy for the diagnosis of PD of 92 %, 88 % and 90 % for radiologist 1 and 83 %, 88 % and 85 % for radiologist 2, respectively. CONCLUSION: PADRE is able to identify PD in patients as a loss of delineation between the crural fibres and the substantia nigra on an individual basis.

Delineation of optic radiation and stria of Gennari on high-resolution phase difference enhanced imaging.

RATIONALE AND OBJECTIVES: Phase difference enhanced (PADRE) imaging technique can selectively enhanced the phase difference between the target and surrounding tissue. Our purpose is to assess the delineations of the optic radiation and primary visual cortex (stria of Gennari) using PADRE. MATERIALS AND METHODS: The subjects were 6 healthy volunteers. Axial and coronal high-spatial resolution PADRE images were acquired covering the entire optic radiation using a 3T magnetic resonance system. Two radiologists evaluated the PADRE and susceptibility-weighted imaging (SWI)-like images for the delineation of four layers at the optic radiation (tapetum, internal sagittal stratum, external sagittal stratum, and adjacent white matter) on the basis of the anatomic appearances of the cadaveric specimens stained with Bodian's method and Kluver-Barrera method. The radiologists also assessed the delineations of the stria of Gennari on PADRE and SWI-like images. RESULTS: In all 6 healthy subjects, the PADRE images clearly identified the four layers at the optic radiation, as well as the stria of Gennari, which were difficult to appreciate in SWI-like images. The anatomic appearances of the optic radiation on PADRE images were more similar to those seen in the specimens stained with Kluver-Barrera method than with Bodian's method. CONCLUSION: The PADRE technique can delineate the four layers at the optic radiation and the stria of Gennari; the differences in myelin densities can also be enhanced. The PADRE technique may have the potential to reinforce the clinical utility of MRI in the diagnosis of diseases that affect the optic radiation and primary visual cortex.

Pitfalls of 3D FLAIR brain imaging: a prospective comparison with 2D FLAIR.

RATIONALE AND OBJECTIVES: To prospectively compare the image contrast of various brain lesions on two-dimensional (2D) and three-dimensional (3D) fluid-attenuated inversion-recovery (FLAIR) images and to highlight the pitfalls of 3D FLAIR. MATERIALS AND METHODS: Institutional review board approval was obtained. We examined 94 brain lesions with 2D and 3D FLAIR at 3T. First, we optimized the repetition time and echo time of 3D FLAIR with a volunteer study. Then, we assessed the conspicuity and detection of the various lesions qualitatively, and the contrast ratio between the gray or white matter and lesions was calculated as a quantitative assessment. We also performed a phantom study to investigate the effects of different flow velocities on 2D and 3D FLAIR. RESULTS: With regard to the conspicuity and detection of most lesions (multiple sclerosis, ischemic lesions or infarction, brain tumors, or chronic trauma), 3D FLAIR was equal or superior to 2D FLAIR. For these lesions, the mean contrast ratios were higher on 3D FLAIR than on 2D FLAIR images. In terms of lesion conspicuity in the patients with hippocampal sclerosis and leptomeningeal metastasis, however, 3D FLAIR was equal or inferior to 2D FLAIR. The ivy sign in patients with moyamoya disease was frequently obscured on 3D FLAIR. The phantom study demonstrated that the signal-intensity ratio on 3D FLAIR decreased more rapidly with increasing velocity than that on 2D FLAIR. CONCLUSION: Although 3D FLAIR may replace 2D FLAIR images for most patients, radiologists should keep in mind that 3D has some pitfalls.

[Evaluation of the detectability of vascular stenosis using non-contrast magnetic resonance angiography with various electrocardiographically-gated three-dimensional fast spin echo sequences].

Various three-dimensional fast spin echo (3D-FSE) sequences are used for non-contrast magnetic resonance angiography (MRA). Differences in the ability to detect vascular stenosis using these sequences, however, have not yet been evaluated. The purpose of this study is to evaluate the usefulness of each sequence for the detection of vascular stenosis by using a vascular phantom. The phantom consisting of silicon tubes with 30% and 70% stenosis of luminal diameter and fluids close to T2 value of blood were used for the study. Non-contrast MRA with half-Fourier acquisition single-shot turbo spin echo (HASTE)-noncontrast magnetic resonance angiography of arteries and veins (NATIVE), sampling perfection with application optimized contrasts using different flip angle evolutions (SPACE)-NATIVE, fresh blood imaging (FBI) and triggered angiography non contrast enhanced (TRANCE) sequences was performed by using the phantom which can be varied in terms of the steady flow velocity. Each stenosis was quantitatively estimated by the stenosis index (SI) calculated from the signal intensities on acquired images. The signal intensity of the non-stenotic vascular site markedly decreased at more than a flow rate of 20 cm/s in all sequences. Significant decrease in the signal intensity was observed in the distal point from the stenosis area on these images acquired by using HASTE-NATIVE and FBI sequences. FBI and TRANCE sequences showed a more accurate SI for 30% stenosis than HASTE-NATIVE and SPACE-NATIVE sequences. SI for 70% stenosis was overestimated in all sequences at 5 cm/s of diastolic flow rate. In conclusion, the ability to detect vascular stenosis on non-contrast MRA image using 3D-FSE sequences depends on the image quality during diastolic phase in the cardiac cycle. FBI and TRANCE sequences are useful to detect the mild arterial stenosis.

A novel tract imaging technique of the brainstem using phase difference enhanced imaging: normal anatomy and initial experience in multiple system atrophy.

OBJECTIVES: To develop a new tract imaging technique for visualising small fibre tracts of the brainstem and for detecting the abnormalities in multiple system atrophy of the cerebellar type (MSA-C) using a phase difference enhanced (PADRE) imaging technique, in which the phase difference between the target and surrounding tissue is selectively enhanced. METHODS: Two neuroradiologists compared the high-spatial-resolution PADRE imaging, which was acquired from six healthy volunteers, three patients with MSA-C, and 7 patients with other types of neurodegenerative diseases involving the brainstem or cerebellum. RESULTS: Various fine fibre tracts in the brainstem, the superior and inferior cerebellar peduncles, medial lemniscus, spinothalamic tract, medial longitudinal fasciculus, central tegmental tract, corticospinal tract and transverse pontine fibres, were identified on PADRE imaging. PADRE imaging from MSA-C demonstrated the disappearance of transverse pontine fibres and significant atrophy of the inferior cerebellar peduncles, while the superior cerebellar peduncles were intact. PADRE imaging also demonstrated that the transverse pontine fibres and inferior cerebellar peduncle were not involved in the other neurodegenerative diseases. CONCLUSION: PADRE imaging can offer a new form of tract imaging of the brainstem and may have the potential to reinforce the clinical utility of MRI in differentiating MSA from other conditions.

[A fundamental study of non-contrast enhanced MR angiography using ECG gated-3D fast spin echo at 3.0 T].

Contrast-enhanced magnetic resonance angiography (CE-MRA) is frequently performed in body and extremity studies because of its superior ability to detect the vascular stenosis. However, nephrotoxicity of the contrast medium has been emphasized in recent years. Non-contrast MRA using the three-dimensional electrocardiogram-synchronized fast spin echo method (FBI, NATIVE and TRANCE) is recommended as a substitute for CE-MRA. There are a few reports in the literature that evaluate the detectability of vascular stenosis using non-contrast MRA on 3.0 T MRI. The purpose of this study was to evaluate the detectability of vascular stenosis using non-contrast MRA at 3.0 T with an original vascular phantom. The vascular phantom consisted of silicon tubes. 30% and 70% stenosis of luminal diameter were made. Each silicon tube connected a pump producing a pulsatile flow. A flowing material to was used in this study to show the similarity of the intensity to blood on MRI. MRA without a contrast medium (NATIVE sequence) were performed in the vascular phantom by changing the image matrix, static magnetic field strength and flow velocity. In addition, the NATIVE sequence was used with or without flow compensation. Vascular stenosis was quantitatively estimated by measurement of the signal intensities in non-contrast MRA images. MRA with NATIVE sequence demonstrated an accurate estimation of 30% vascular stenosis at slow flow velocity. However, 30% stenosis was overestimated in cases of high flow velocity. Estimation was improved by using a flow compensation sequence. 70% stenosis was overestimated on MRA with NATIVE sequence. Estimation of 70% stenosis was improved by using a flow compensation sequence. Accurate estimation of vascular stenosis in MRA with a NATIVE sequence is improved by using the flow compensation technique. MRA with NATIVE sequence is considered to be a promising method for the evaluation of patients with severe renal dysfunction as a substitute for CT angiography or CE-MRA.

Handedness: dependent asymmetrical location of the human primary gustatory area, area G.

In magnetoencephalogram studies, the primary gustatory area, area G, is not always seen in the same coronal plane in both hemispheres. We investigated possible asymmetry in right-handed and left-handed individuals by functional MRI. Group analyses revealed a significant difference in the antero-posterior coordinates of the area G between the right and left hemispheres in the right-handed group, but not in the left-handed group, indicating significant morphometric asymmetry in the former group and ambiguous morphometric asymmetry in the latter. However, in left-handed individuals with motor speech areas detected in the right hemisphere, area G was more posteriorly located in the right than in the left hemisphere. These findings suggest that the motor speech area contributes to the asymmetric location of area G.

MRA of intracranial aneurysms embolized with platinum coils: a vascular phantom study at 1.5T and 3T.

PURPOSE: To analyze the influence of matrix and echo time (TE) of three-dimensional time-of-flight (3D TOF) magnetic resonance angiography (MRA) on the depiction of residual flow in aneurysms embolized with platinum coils at 1.5T and 3T. MATERIALS AND METHODS: A simulated intracranial aneurysm of the vascular phantom was loosely packed to maintain the patency of some residual aneurysmal lumen with platinum coils and connected to an electromagnetic flow pump with pulsatile flow. MRAs were obtained altering the matrix and TE of 3D TOF sequences at 1.5T and 3T. RESULTS: The increased spatial resolution and the shorter TE offered better image quality at 3T. For the depiction of an aneurysm remnant, the high-spatial-resolution 3T MRA (matrix size of 384 x 224 and 512 x 256) with a short TE of < or =3.3 msec were superior to the 1.5T MRA obtained with any sequences. CONCLUSION: 3T MRA is superior to 1.5T MRA for the assessment of aneurysms embolized with platinum coils; the combination of the 512 x 256 matrix and short TE (3.3 msec or less) seems feasible at 3T.

3D TOF MRA of intracranial aneurysms at 1.5 T and 3 T: influence of matrix, parallel imaging, and acquisition time on image quality - a vascular phantom study.

RATIONALE AND OBJECTIVES: A 3-T magnetic resonance imaging system provides a better signal-to-noise ratio and inflow effect than 1.5 T in three-dimensional time-of-flight (3D TOF) magnetic resonance angiography (MRA). The purpose of this study is to analyze the influence of matrix, parallel imaging, and acquisition time on image quality of 3D TOF MRA at 1.5 and 3 T, and to illustrate whether the combination of larger matrixes with parallel imaging technique is feasible, by evaluating the visualization of simulated intracranial aneurysms and aneurysmal blebs using a vascular phantom with pulsatile flow. MATERIALS AND METHODS: An anthropomorphic vascular phantom was designed to simulate the various intracranial aneurysms with aneurysmal bleb. The vascular phantom was connected to an electromagnetic flow pump with pulsatile flow, and we obtained 1.5- and 3-T MRAs altering the parameters of 3D TOF sequences, including acquisition time. Two radiologists evaluated the depiction of simulated aneurysms and aneurysmal blebs. RESULTS: The aneurysmal blebs were not sufficiently visualized on the high-spatial resolution 1.5-T MRA (matrix size of 384 x 256 or 512 x 256), even with longer acquisition time (9 or 18 min). At 3 T with acquisition time of 4.5 min using parallel imaging technique, however, the depiction of aneurysmal blebs was significantly better for the high-spatial resolution sequence than for the standard resolution sequence. For the high-spatial resolution sequence, the longer acquisition times did not improve the depiction of aneurysmal blebs in comparison with 4.5 min at 3 T. CONCLUSIONS: For 3D TOF MRA, the combination of the large matrix with parallel imaging technique is feasible at 3 T, but not at 1.5 T.

Positional lumbar imaging using a positional device in a horizontally open-configuration MR unit - initial experience.

PURPOSE: To evaluate whether positional MR images of the lumbar spine, obtained with a horizontally open-configuration MR unit, demonstrate positional changes of the dural sac, and to assess whether there are significant differences in positional changes between healthy volunteers and patients with chronic low back pain. MATERIALS AND METHODS: The study population consisted of 15 patients with chronic low back pain and 14 healthy volunteers. MR images were obtained using a horizontally open-configuration 0.4-T MR unit. After conventional lumbar MR examinations, images were obtained in the flexion, neutral, and extension positions, using a positioning device. The anteroposterior diameter of the dural sac at the level of each lumbar disk was measured in the three positions and quantitative data were compared. RESULTS: Our MR protocol was tolerated by all patients. In both patients and volunteers, the mean anteroposterior diameter of the dural sac was smaller in the extension positions than in the flexion positions. In the mean rate of change (RC) in the dural sac diameter at the site of the degenerated disks, the difference between the volunteers and patients was significant (P < 0.05). There was no significant difference in the mean RC between patients and volunteers without degenerative disks. CONCLUSION: Using a horizontally open-configuration MR unit, positional MR imaging provided position-dependent change of the dural sac. Positional changes at the site of the degenerated disks may be different in patients with and without chronic low back pain.

Detection of hemorrhagic hypointense foci in the brain on susceptibility-weighted imaging clinical and phantom studies.

RATIONALE AND OBJECTIVES: To determine the sensitivity of susceptibility-weighted imaging (SWI) for depicting hemorrhagic hypointense foci of the brain in comparison with gradient-recalled echo (GRE)- and GRE-type single-shot echo-planar imaging (GREI, GRE-EPI), and to assess the basic characteristics of the susceptibility effect by using a phantom. MATERIALS AND METHODS: We prospectively examined 16 patients (9 males, 7 females, aged 10-74 years, mean 43 years) with hypointense foci using SWI, GREI, and GRE-EPI at a 1.5-T magnetic resonance (MR) unit. The contrast-to-noise ratio (CNR), sensitivity to small hypointese foci, and artifacts were evaluated. To assess the basic characteristics of SWI, we performed a phantom study using different concentrations of superparamagnetic iron oxide (SPIO). RESULTS: The CNR of lesions was significantly greater for SWI than the other images (P < .0001). SWI detected the greatest number of small hypointense foci, even in the near-skull-base and infratentorial regions. Quantitative and qualitative analyses in our clinical and phantom studies demonstrated that the degree of artifacts was similar with SWI and GREI. CONCLUSION: SWI was best for detecting small hemorrhagic hypointense foci. Artifacts of SWI were similar to GREI.

Detection of brain metastasis at 3T: comparison among SE, IR-FSE and 3D-GRE sequences.

The objective of this study is to compare the detectability of brain metastases at 3T among three contrast-enhanced sequences, spin-echo (SE) sequence, inversion recovery fast SE (IR-FSE) sequence (both with section thickness of 6 mm), and three-dimensional fast spoiled gradient-echo (3D fast SPGR) sequence with 1.4 mm isotropic voxel. First, phantom studies were performed to quantify the contrast-enhancement ratio (CER) with three sequences. In 21 consecutive patients with brain metastases, axial images of three sequences at 3T were obtained after administration of gadoteridol. Two neuroradiologists assessed the detectability of brain metastases for the three sequences. In the phantom study, no evident difference in the CER was demonstrated among three sequences. Significantly more brain metastases were detected with 3D fast SPGR than with SE and IR-FSE (a total of 97 lesions with 3D fast SPGR vs. 64 with SE and 63 with IR-FSE). In particular, 3D fast SPGR was superior to the other two sequences in detection of the small lesions (<3 mm). At 3T, the contrast-enhanced 3D fast SPGR with 1.4 mm isotropic voxel is clinically more valuable for detecting small brain metastases than the SE and IR-FSE with section thickness of 6 mm.

Interactive scan control for kinematic study in open MRI.

PURPOSE: A tool to support the subject is generally used for kinematic joint imaging with an open MRI apparatus because of difficulty setting the image plane correctly. However, use of a support tool requires a complicated procedure to position the subject, and setting the image plane when the joint angle changes is time consuming. Allowing the subject to move freely enables better diagnoses when kinematic joint imaging is performed. We therefore developed an interactive scan control (ISC) to facilitate the easy, quick, and accurate setting of the image plane even when a support tool is not used. METHODS: We used a 0.4T magnetic resonance (MR) imaging system open in the horizontal direction. The ISC determines the image plane interactively on the basis of fluoroscopy images displayed on a user interface. The imaging pulse is a balanced steady-state acquisition with rewound gradient echo (SARGE) sequence with update time less than 2 s. Without using a tool to support the knee, we positioned the knee of a healthy volunteer at 4 different joint angles and set the image plane through the patella and femur at each of the angles. Lumbar imaging is also demonstrated with ISC. RESULTS: Setting the image plane was easy and quick at all knee angles, and images obtained clearly showed the patella and femur. Total imaging time was less than 10 min, a fourth of the time needed when a support tool is used. We also used our ISC in kinematic imaging of the lumbar. CONCLUSION: The ISC shortens total time for kinematic joint imaging, and because a support tool is not needed, imaging can be done more freely in an open MR imaging apparatus.

Automated hepatic volumetry for living related liver transplantation at multisection CT.

PURPOSE: To prospectively compare in vivo hepatic automated volumetry with manual volumetry and measured liver volume. MATERIALS AND METHODS: The study was conducted in accordance with the guidelines of the Institutional Review Board of Kumamoto University (Japan). Patient informed consent was obtained. Preoperative multisection computed tomography (CT) was performed in 35 consecutive patients (21 men, 14 women; mean age, 42.8 years; range, 28-72 years) with hepatic disease awaiting living related liver transplantation. The CT scans covered the entire liver at a section thickness of 2.5 mm. Liver volume was estimated by using both the automated and the manual methods. Actual liver weight was obtained for all patients and was converted to hepatic volume on the basis of a predetermined relationship between actual liver weight and volume. Processing time required for both methods was also recorded. Two-tailed paired t test, correlation coefficient, and Bland-Altman tests were used for statistical analyses. RESULTS: Mean liver weight was 881.7 g +/- 249.8 (standard deviation), and mean measured liver volume was 956.00 cm(3) +/- 280.10. Volumetry performed with the automated and manual methods provided liver volumes of 982.99 cm(3) +/- 301.98 and 937.10 cm(3) +/- 301.31, respectively. There was good correlation between measured and estimated volumes obtained with the automated method (r = 0.792, P < .01). The manual and automated methods required 32.8 minutes +/- 6.9 and 4.4 minutes +/- 1.9, respectively. CONCLUSION: The automated method reduced the time required for volumetry of the liver and provided acceptable measurements.

[Comparison of LCD and CRT monitors for detection of pulmonary nodules and interstitial lung diseases on digital chest radiographs by using receiver operating characteristic analysis].

Soft copy reading of digital images has been practiced commonly in the PACS environment. In this study, we compared liquid-crystal display (LCD) and cathode-ray tube (CRT) monitors for detection of pulmonary nodules and interstitial lung diseases on digital chest radiographs by using receiver operating characteristic (ROC) analysis. Digital chest images with a 1000x1000 matrix size and a 8 bit grayscale were displayed on LCD/CRT monitor with 2M pixels in each observer test. Eight and ten radiologists participated in the observer tests for detection of nodules and interstitial diseases, respectively. In each observer test, radiologists marked their confidence levels for diagnosis of pulmonary nodules or interstitial diseases. The detection performance of radiologists was evaluated by ROC analyses. The average Az values (area under the ROC curve) in detecting pulmonary nodules with LCD and CRT monitors were 0.792 and 0.814, respectively. In addition, the average Az values in detecting interstitial diseases with LCD and CRT monitors were 0.951 and 0.953, respectively. There was no statistically significant difference between LCD and CRT for both detection of pulmonary nodules (P=0.522) and interstitial lung diseases (P=0.869). Therefore, we believe that the LCD monitor instead of the CRT monitor can be used for the diagnosis of pulmonary nodules and interstitial lung diseases in digital chest images.