Respiratory motion makes it difficult to quantify myocardial perfusion with dynamic magnetic resonance imaging (MRI). The purpose of this study was to evaluate an automatic registration method for motion correction for quantification of myocardial perfusion with dynamic MRI. The present method was based on the gradient-based method with robust estimation of displacement parameters. For comparison, we also corrected for motion with manual registration as the benchmark. The myocardial kinetic parameters, K₁ (rate constant for transfer of contrast agent from blood to myocardium) and k₂ (rate constant for transfer from myocardium to blood), were calculated from dynamic images with a two-compartment model. The images corrected by the present method were similar to those corrected by manual registration. The kinetic parameters obtained after motion correction with the present method were close to those obtained after motion correction with manual registration. These results suggest that the present method is useful for motion correction for quantification of myocardial perfusion with dynamic MRI.

抄録全体を表示

Purpose: To compare the signal pattern of True FISP (true fast imaging with steady state precession) with that of T₂-weighted TSE (turbo spin echo) sequencing in several ovarian pathologies and to clarify the pathologies that may be misdiagnosed when True FISP is used as a fast T₂-weighted MR (magnetic resonance) imaging technique.
Methods: A total of 56 patients with 58 ovarian lesions were prospectively studied. The histopathological diagnoses were surgically confirmed in all patients. All MR images were acquired with a 1.5T MR scanner. After routine MR examination (T₂-weighted sagittal imaging with a turbo spin echo sequence and T₁ and T₂ transverse imaging with a spin echo and turbo spin echo sequence, respectively), True FISP was performed in the sagittal plane with a fat-saturation technique. The acquisition times for the True FISP and TSE techniques were 27 s and 4 min, 42 s, respectively. Three radiologists interpreted all images according to three grading scores and with particular reference to the difference in signal pattern between the two sequences (1=similar signal patterns in the ovarian lesions in both True FISP and TSE images; 2=partially different signal patterns in both True FISP and TSE images; and 3=conflicting signal patterns in both True FISP and TSE images).
Results: Those assigned a score of “1” included 30 patients with 30 ovarian lesions (12 malignant lesions and 18 benign lesions); those assigned a score of “2” included 10 patients with 10 lesions (two malignant and eight benign); and those assigned a score of “3” included 16 patients with 18 ovarian lesions (two malignant and 16 benign). With the influence of the fat-suppression technique excluded, eight ovarian lesions showed conflicting signal patterns between the two sequences and high signal intensity of hemorrhaging in the corresponding lesion in T₁-weighted images. Lesions of both high and low signal intensity in TSE images appeared as lesions of high signal intensity in True FISP images. About 14% (8/56 lesions) of the True FISP and TSE signal patterns in ovarian pathology were conflicting in this study.
Conclusion: The results indicate that the True FISP technique cannot replace the T₂-weighted TSE technique in the evaluation of ovarian pathology. T₁-weighted images with or without fat suppression are required for the evaluation of ovarian lesions with FISP images.

抄録全体を表示

Background and Purpose: We have encountered a peculiar atrophic change in the midbrain in some patients with parkinsonian syndromes. We discovered these patients had vertical supranuclear gaze-palsy, an eye movement disorder. The purpose of this study was to elucidate whether this atrophic pattern of the midbrain (which we have termed morning glory sign) is related to the vertical eye movement disorder, in particular to progressive supranuclear palsy (PSP).
Methods: We reviewed T₂-weighted axial images obtained from 42 patients with parkinsonian syndromes, including five patients with PSP, 23 patients with Parkinson's disease, and 14 patients with multiple system atrophy (MSA). We focused on a specific atrophy of the midbrain, the morning glory sign, which is a concavity of the lateral margin of the tegmentum of the midbrain.
Results: The morning glory sign was detected in four of the five patients with PSP and in one (striatonigral degeneration; SND) of the14 patients with MSA. All morning glory sign patients had vertical supranuclear gaze-palsy, as did the one PSP patient without the morning glory sign. Vertical supranuclear gaze-palsy was seen in no other patients (23 patients with Parkinson's disease and 13 patients with MSA) who lacked the morning glory sign.
Conclusions: Morphologically, the morning glory sign is believed to be related to vertical supranuclear gaze-palsy. This sign should be considered a useful clue when diagnosing PSP.

抄録全体を表示

The purpose of this paper is to show several diseases that manifest symmetrical hyperintense lesions on the middle cerebellar peduncles, the largest connecting peduncles between the brainstem and the cerebellum, in conventional magnetic resonance (MR) images. We retrospectively reviewed cranial MR images obtained with 0.3-, 0.5-, 1.0-, and 1.5-Tesla scanners. We found symmetrical middle cerebellar peduncular lesions in patients with Wilson's disease; hepatic encephalopathy; extrapontine myelinolysis; acute disseminated encephalomyelitis; wallerian degeneration of the pontocerebellar tracts after either pontine infarction, pontine hemorrhage, or central pontine myelinolysis; leukodystrophy; olivopontocerebellar atrophy; and toluene abuse. Definitive diagnosis of these diseases can be made relatively easily on the basis of clinical data; however, examination of associated brainstem or supratentorial lesions in MR images is also important.

抄録全体を表示

We describe a patient with acute calcific periarthritis in an unusual site, the ilio-femoral ligament. The clinical findings in this patient resembled those of septic arthritis. T₂^*-weighted images with gradient field echo clearly showed foci of low signal intensity in this region, corresponding to the calcification shown on plain radiographs, and increased signal intensity around the foci, representing edema. These signal intensities were diagnostic of the disease.

抄録全体を表示

The purpose of this article is to review the characteristics of computed tomography (CT) and magnetic resonance imaging (MRI) of the pericardium and pericardial diseases. Because patients with pericardial diseases usually present with nonspecific symptoms, these diseases may not be detected until they have reached an advanced stage. It is therefore important to distinguish between normal pericardial structure and disease. Multiplanar reconstruction images of CT and MRI are useful for evaluating faint changes of the pericardium. The specific pericardial diseases described in this article include pericardial cyst, constrictive pericarditis, pericarditis with radiation pericarditis, postoperative pericardial hematoma, and cardiac tamponade due to a paracardiac mass (lymphoma).

抄録全体を表示