Multiple mobile spherules in mature cystic teratoma of the ovary.
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Adult↗
Biomedical subjects
A Heshiki
Publications and source records attributed to A Heshiki.
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.
Aged↗
Chorioangioma: antenatal diagnosis with fast MR imaging.
We report a case of chorioangioma of the placenta, in which fast magnetic resonance imaging (MRI) was useful adjunct to ultrasonography for the antenatal diagnosis. MRI allowed clear demonstration of 6.8 x 6.0 cm solid placental mass along with hydramnios and anatomically normal fetus. On T(1)-weighted breath-hold spoiled gradient-echo (fast low-angle shot [FLASH]) images, chorioangioma was mostly isointense to the placenta, but had an area of high signal intensity near the base and at the periphery, suggestive of hemorrhage. On T(2)-weighted half-Fourier single-shot fast spin echo (HASTE) images, the mass showed heterogeneous high signal intensity, but had an area of low signal intensity near the surface.
Adult↗
[Radiation dose measurement of the patient in interventional radiology using a transmission ionization chamber].
We propose a method to estimate patient radiation dose in radiologically guided interventional procedures using a transmission ionization chamber. A typical transarterial embolization (TAE) procedure for hepatocellular carcinoma was simulated, including 30 minutes of fluoroscopy and five series of DSA, each with appropriate collimation. The dose-area product was divided by the area and compared with values from a standard dosimeter placed in the center of the radiation entrance, to obtain a conversion factor. In this way, the entrance skin dose can be estimated immediately after the procedure by simply multiplying the value by the conversion factor, if the procedure roughly conforms to the simulated model. The average entrance skin dose of 33 patients who recently underwent TAE for HCC was found to be 0.66 (0.19-1.75) Gy. This technique can be applied to other areas of IVR and may help to reduce patient exposure to radiation.
Carcinoma, Hepatocellular↗
[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.
Adult↗
[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.
Aged↗
[Detection of recurrent rectal cancer using helical CT with SmartPrep: a new technique for obtaining optimal contrast enhancement].
Seven patients with suspected recurrent rectal cancer underwent Helical CT using SmartPrep. SmartPrep is a software application developed by GE in which the ROI is placed at the desired level of the aorta prior to contrast injection. Using a low-dose continuous scan, the time density curve was obtained instantly, and the optimal timing of scanning was judged from the curve. Four patients who demonstrated intense enhancement at the anastomotic site had local recurrence. No intense enhancement was observed in these areas on conventional delayed CT. Thus, SmartPrep appears to be useful for the accurate diagnosis of recurrent rectal cancer.
Aged↗
[Normal sternal bone marrow MRI using STIR].
The MR signal of sternal bone marrow was examined in 21 normal volunteers using a sagittal STIR sequence. Craniocaudal phase-encoding with a hand-made positioning device effectively eliminated artifacts due to cardiac pulsation. The sternal bone marrow signal could be classified into three patterns based on the signal distribution. The superior segment of the manubrium showed characteristic age-related changes. This method provided high spatial resolution and excellent bone marrow imaging. Knowledge of a normal marrow signal pattern may be useful for the evaluation of hematological disorders.
Adult↗
Magnetic resonance imaging patterns in patients with multiple myeloma.
Sixty-one consecutive patients with multiple myeloma were studied with magnetic resonance (MR) imaging of the spine. Sagittal T1-weighted and short inversion time (TI) inversion recovery (STIR) images were obtained. The MR patterns of the bone marrow were classified as diffuse (D) (n=26), nodular (N) (n=11), D+N (n=13) or normal (n) (n=11). Abnormal patterns were seen in 50 (82%) of the 61 patients. Correlations were found between the MR imaging patterns and some laboratory findings (WBC, haematocrit, platelet count, serum albumin, and percentage of marrow plasmacytosis). The survival of the patients with abnormal MRI patterns was significantly poorer than that of the patients with normal patterns. However, the survival of patients with a nodular pattern did not differ from those with a normal pattern. The MR imaging pattern of the bone marrow in patients with multiple myeloma is a useful factor in the assessment of prognosis.
Adult↗
Bone marrow patterns in patients with aplastic anaemia and myelodysplastic syndrome: observations with magnetic resonance imaging.
Bone marrow magnetic resonance imaging (MRI) was obtained in 48 patients with myelodysplastic syndrome (MDS) (35 cases) or aplastic anaemia (AA) (13 cases). The lower thoracic and lumbar spine were evaluated on sagittal plane using a 1.5 Tesla superconducting MR unit with a surface coil. Pulse sequence of STIRs (TR 2000 msec, TI 160 msec, TE 20 msec) were applied. Four distinct patterns of signal intensity (SI) on the STIR images were classified as follows: pattern 1, homogeneously low SI; 2, marginally high SI; 3, heterogeneously high SI; 4, homogeneously high SI. In all 13 patients with AA, STIR images initially revealed pattern 1. In 25 of 35 cases with MDS patients, the STIR images were initially classified as pattern 3. The STIR images of 6 AA and 5 MDS patients with a clinical response to treatment showed pattern 2 similar to that of normal marrow distribution. The STIR images of MDS patients showed an abnormal distribution of SI. Significant signal changes in the STIR images can be observed in successive examinations of the patients, thus facilitating follow-up of the disease and treatment. MRI of the bone marrow provides a noninvasive means of grossly examining a large fraction and is a useful technique in patients with aplastic anaemia or myelodysplastic syndrome.
Adolescent↗
[Application of diffusion-weighted echo planar imaging for diagnosis of small acute and subacute brain ischemic lesions].
The aim of this study was to determine the utility of diffusion-weighted echo planar imaging (DW-EPI) for detecting acute and subacute brain ischemic foci less than 2 cm in size. Thirty patients underwent DW-EPI on a 1.5 T superconducting unit using a SE-EPI sequence with an arbitrary pair of Stejskal-Tanner gradients applied along the imaging axes. DW-EPI demonstrated all the mast recent ischemic lesions as areas of decreased diffusion, providing greater conspicuity and larger size than conventional spin-echo imaging. DW-EPI is a promising method to detect within a subsecond early ischemia and reversible ischemic changes that are not demonstrate on routine spin-echo images.
Acute Disease↗
[Enhanced 3D subtraction MR angiography of head and neck tumors].
Contrast-enhanced three-dimensional MR angiography (MRA) combined with a subtraction technique was performed in six patients with a solid tumors in the head or neck region. Using the subtraction technique, the contrast-to-noise ratio between the internal carotid artery and fat tissue increased from 18.2 +/- 7.4 to 64.7 +/- 30.8. The MRA findings demonstrated both arteries and enhancing tumors with effective background signal suppression, making tumor extension and relation to the arterial branches more evident. The proposed technique is promising for screening arterial abnormalities of the head and neck in patients with solid tumors.
Head and Neck Neoplasms↗
[Bone marrow MRI in hematological disorders].
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Bone Marrow↗
[Magnetization transfer MR of cerebrovascular disorders using calculated images].
This study applied a magnetization transfer contrast method to patients with cerebrovascular disorders. A 1.5T superconducting MR unit was used, and magnetization transfer ratio (MTR) images were calculated by evaluating two paired images before and after off-resonance gradient echo pulse sequences. The normal white matter showed the highest MTRs, CSF the lowest, and gray matter, intermediate. Cerebral ischemic patients showed two patterns according to the chronological stage of the affected area. Lesions in the acute and subacute stages revealed higher transfer rates than those in the chronic stage. Patients with cerebral hemorrhage were divided into three groups: the hyperacute group showed a low transfer pattern; the acute group presented inhomogeneous high transfer rates; and the subacute group showed remarkably low transfer rates. In the acute and subacute ischemic stages, increased macromolecules caused higher MTRs than in the chronic stage. In hemorrhagic groups, low MTRs in subacute hemorrhage reflected the transfer of methemoglobin. High MTRs in acute hemorrhage with rich deoxyhemoglobin suggested increased fibrin, plasma, and serum components of macromolecules. The MTC method provided new chronological information on cerebral hemorrhage, adding to that provided by routine MR images.
Adolescent↗
[Contrast-enhanced 3D MR angiography of the chest and abdomen with breath-holding using phase reordering].
This report presents the feasibility of phase-recordered contrast-enhanced three-dimensional MR angiography in 32 consecutive patients with vascular abnormalities in the chest and abdomen. To suppress motion artifacts due to respiratory corruption, a phase-reordering technique was introduced so that the low frequency components of the phase data were obtained first during the imaging period. Image quality and degree of motion suppression were assessed by four radiologists independently without information on breath-holding time. Abnormalities were detected in 30 cases (93.8%), and their extent was correctly assessed in 28 cases (87.5%). More confident assessment was possible in abnormalities of the pulmonary vessels and thoracic aorta than in those of the abdominal aorta and portal venous system. With phase reordering, more than 20 seconds of breath-holding ensured image quality sufficient to correctly assess the vascular abnormalities. While this technique is easy and requires only single breath-holding, it can provide excellent MRA without slice-to-slice spatial misregistration.
Aortic Aneurysm, Abdominal↗
[MR imaging of temporomandibular joint (TMJ): mandibular fracture and traumatic disk injury].
Using an 1.5 Tesla superconducting MR unit and surface coil, 12 mandibular fracture patients were evaluated for TMJ disk change. Sagittal and coronal images of the TMJ with a slice thickness of 2mm were obtained with FISP 2D or 3D. TR = 30 msec, TE = 12 msec, and flip angle = 40 degrees were applied. Among 12 patients, FISP 3D revealed increased signal intensity of the disk in 70% of cases. Traumatic fluid collection at or adjacent to the TMJ showed high intensity. The disk was displaced anteromedially regardless of the site of fracture.
Adolescent↗
[Breath-holding three-dimensional MR imaging: evaluation of phase reordering for motion artifact suppression].
To suppress image degradation due to respiratory corruption during breath holding, a method of reordering of phase encoding was introduced in three-dimensional MR imaging. Without trade-offs in SNR, CNR, and examination time, the method provided a significant reduction of respiratory motion-induced artifacts both in phantom and in vivo experiments. More than twenty seconds of breath holding ensured acceptable image quality regardless of respiratory motion thereafter. Signal intensity change during data acquisition altered the obtained image contrast compared with that of standard sequential linear phase encoding. This technique can be readily implemented on standard two-and three-dimensional pulse sequences and will improve image quality when a patient cannot hold his/her breath during the whole imaging period.
Artifacts↗
[Imaging diagnosis in border-less age].
Several proposals were made under the title of imaging diagnosis of border-less age. One was the wide range of application of multimedia in medicine. The application is in the world wide scale, such as information super highway, and information technology vision 2000, and so forth. Second and third proposals were to promote clinical and basic research groups beyond specialities to make micro and micron imaging possible both in morphology and function. As an example, imaging of interstitium of the bone marrow by magnetic resonance microimaging was discussed. To convey these concepts, multidiscipline and inter- and intra-speciality work is mandatory. Finally, PACS and telecommunication were introduced as one of the tools of imaging diagnosis in border-less age with illustration of PACS system at Saitama medical school.
Diagnostic Imaging↗