[False-negative cases of axillary ultrasonography: how much size?].

PURPOSE/AIM: 1. To review the sonographic criteria of axillary lymph node status in breast cancer patients. 2. To understand imaging pathologic correlations that the false-negative cases of axillary ultrasonography. CONTENT ORGANIZATION: The sonographic criteria, the accuracy of sonographic axillary ultrasonography, imaging pathologic correlations in false-negative cases, measurement of largest malignant focus size in lymph node, classification of ratio of malignant focus size, ratio of micro metastasis. SUMMARY: 1. Recently, lymph node evaluation that using serial section and immunohistochemical stains makes it difficult to detect imaging modalities. 2. Ultrasonography is limited how to detect the example of sentinel lymph node biopsy non-indications.

Evaluation of chest wall invasion by lung cancer using respiratory dynamic MRI.

Conventional CT or MRI has low accuracy in assessing chest wall invasion in patients with peripheral lung cancer. For preoperative evaluation of chest wall invasion by peripheral lung cancer, respiratory dynamic (RD) MRI was carried out in 98 patients in whom conventional CT scan showed that the tumour was abutting the pleural surface, but there was no evidence of definite tumour invasion. We used 1.5-T MR equipment. RD MR images were acquired by snapshot fast field echo sequence (repetition time = 8, echo time = 3, flip angle = 100) and 25 consecutive images were taken while the patient took deep breaths. These images were evaluated in cine mode to assess tumour movement along the chest wall. Sixty-one patients underwent surgical resection of the tumour and RD MR findings were compared with those in pathological specimens. RD MR showed free tumour movement along the chest wall in 34 patients. At pathological examination, the RD MR findings were proved correct in all patients. Pathologically, 20 patients had chest wall invasion and their RD MR was positive (sensitivity 100%). There were seven false-positive results among the 41 patients without chest wall invasion (specificity 82.9%). RD MR may improve the accuracy of conventional CT scan or MRI in the prediction of chest wall invasion of lung cancer, especially in patients in whom the results of conventional CT scan or MRI appear equivocal in the presence of a peripheral mass abutting the chest wall surface without obvious chest wall invasion.

Barium aspiration showing crazy-paving appearance on high-resolution computed tomography.

We encountered a case showing a crazy-paving appearance on high-resolution computed tomography (HRCT), which mimicked various pulmonary diseases, e.g. pulmonary alveolar proteinosis, or non-specific interstitial pneumonia, but which we ultimately determined to be due to barium aspiration. The initial radiological findings were considered to be most likely due to pulmonary alveolar microlithiasis, because the crazy-paving appearance had high density, resembling calcification. However, distribution was limited to the area of dependent drainage of the right lung. Since a barium swallowing study had been performed 2 weeks before the CT examination, and since the follow-up HRCT showed improvement we reached a diagnosis of barium aspiration. Although barium aspiration may yield findings similar to other diseases with crazy-paving appearance, it is possible to identify it because of the limited distribution and high density.

Multiplanar reconstruction MR image of primary adenoid cystic carcinoma of the central airway: (MPR of central airway adenoid cystic carcinoma).

Multiplanar reconstruction (MPR) is a method that allows free selection of computerized reconstruction images. We reviewed a total of six MPR magnetic resonance (MR) examinations in five cases of adenoid cystic carcinoma of the central airway, which is a rare low-grade malignant tumor. MPR MR provides images either longitudinally or at right angles to the longitudinal axis of the trachea and main bronchi, so it was useful to diagnose tumor extent along airways more precisely and to evaluate therapeutic effects. MPR MR may help in planning therapeutic strategy and in posttherapeutic follow-up.

[Dynamic MR imaging of liver lesions with superparamagnetic iron oxide (SH-U-555A)].

Dynamic MRI with SH-U-555 (SPIO) was evaluated. Dynamic MRI was performed for 17 patients with 22 lesions. Dynamic study with T2*-weighted imaging (T2* dynamic) and T1-weighted imaging (T1 dynamic) were performed in 8 cases (10 lesions) and 9 cases (12 lesions), respectively. T2* dynamic MR images were obtained before and 30, 90, 180, 270, 360, and 450 seconds and 31 minutes after the intravenous injection of SPIO, and T1 dynamic MR images were obtained before and 0, 40, 80, 120, 180, 240, 300, 360, 420, and 480 seconds and 28 minutes after the injection of SPIO. The signal intensity of each lesion was measured before and after the injection of SPIO. The enhancement ratio of the lesions was calculated and evaluated. The enhancement ratio of hypervascular lesions decreased rapidly in the first phase of T2* dynamic MRI, while that of hypovascular lesions decreased gradually. The enhancement ratio of hypervascular lesions increased in the first phase of T1 dynamic MRI and decreased gradually, while that of hypovascular lesions lacked the increase in the first phase, in contrast to hypervascular lesions. However, the changing of signal intensity could not be recognized on images with T2* dynamic and T1 dynamic study. In conclusion, quantitative analysis using the enhancement ratio made it possible to anticipate lesion vascularity.

Venous hemangioma of the mediastinum.

Mediastinal hemangiomas are rare tumors. We present a case of venous hemangioma of the mediastinum. Computed tomography shows anterior mediastinal solid mass without enhancement effects. We believe that it is necessary to include a mediastinal hemangioma for differential diagnosis, when little or no enhancement effects are noted at early and delayed CT examination.

MR features of a case of chronic expanding hematoma.

We describe a patient with chronic expanding hematoma that was pathologically confirmed by examination of the resected specimen. It has increased gradually in the right lower lung field during a period of 10 years without symptoms. The MR T2-weighted image was useful to establish a diagnosis of chronic expanding hematoma, because of the mosaic of various signal intensities we named the "mosaic sign".

Gallium-67 scintigraphic findings in a patient with breast lymphoma complicated with Sjögren syndrome.

We report here a patient with mucosa associated lymphoid tissue (MALT)-lymphoma of the breast complicated with Sjögren syndrome. It is speculated that Ga-67 could accumulate not only in lymphoma lesions but also in benign lymphoproliferative locations of Sjögren syndrome. Gallium-67 scintigraphy might be useful for the diagnosis and therapeutic monitoring of MALT-lymphoma complicated with Sjögren syndrome.

Regional differences in diffusion abnormality in cerebral white matter lesions in patients with vascular dementia of the Binswanger type and Alzheimer's disease.

We investigated changes in water diffusion in the cerebral white matter of 14 patients with vascular dementia of the Binswanger type (VDBT) and ten patients with Alzheimer's disease (AD) with periventricular hyperintensity (PVH) lesions using diffusion-weighted magnetic resonance imaging (MRI) and studied the pathophysiological differences between white matter lesions found in these two conditions. Apparent diffusion coefficients (ADCs) in the anterior and posterior white matter and the genu and splenium of the corpus callosum were significantly higher in both groups of patients than in the 12 age-matched controls, and ADC values in VDBT and AD groups were almost the same. ADC ratios, defined as diffusion restricted perpendicular to the direction of nerve fibers, were also significantly higher in the patients than in the control subjects. However, there were regional differences in ADC ratios in the two conditions, with ratios in VDBT being higher in the anterior portions of the white matter but ratios in AD were higher in the posterior portions. The diffusion-weighted MRI technique may be useful in the differential diagnosis of VDBT and AD with white matter lesions.

[A case of choroidal malignant melanoma in which 123I-IMP scintigraphy was useful for diagnosis].

A case of choroidal malignant melanoma in which N-isopropyl-p-[123I]-iodoamphetamine (123I-IMP) scintigraphy was useful for diagnosis is reported. A 62-year-old man first visited our hospital 3 years ago complaining of decreases in left eyesight. CT showed a tumor with an arcuate high attenuation area on the aural side of the optic disk in the left eye. A crescent high attenuation area, evidence of retinal detachment, was also observed on the nasal side of the optic disk. T1-weighted MR images showed low signal intensity in most of the tumor and a high signal intensity area was seen in the center, T2-weighted MR images showed homogeneous and marked low signal intensity area. Differentiation from a hematoma or a vascular tumor associated with bleeding was impossible based on CT and MRI. However, because late-phase images obtained on 123I-IMP scintigraphy showed marked high accumulation in an area corresponding to almost the entire left eye, left eye enucleation was undertaken under a diagnosis of malignant melanoma. Histopathologic examinations showed tumor growth mainly in the subretinal area. The melanin content of the tumor was high in the periphery and relatively low in the center. Infiltration was observed into the sclera and around the vortex vein outside the eyeball, but this change could not be detected by CT or MRI. 123I-IMP scintigraphy was useful not only for qualitative diagnosis of choroidal malignant melanoma, but for the determination of the extent of the lesion as well.

[Salivary gland masses: dynamic MR imaging and pathologic correlation].

PURPOSE: To evaluate the efficiency of dynamic contrast-enhanced magnetic resonance imaging (MRI) for the diagnosis of salivary gland masses. MATERIALS AND METHODS: We retrospectively examined 19 salivary gland masses that were pathologically diagnosed by surgical operation or biopsy. We obtained T1- and T2-weighted images on MRI, performed dynamic studies on each mass and examined the correlation between enhancement patterns and pathological findings. RESULTS: Four enhancement patterns were recognized on contrast-enhanced MRI: type 1 showed marked, homogeneous enhancement; type 2 slight, homogeneous enhancement; type 3 marginal enhancement; and type 4 poor enhancement of the mass. Most pleomorphic adenomas had a type 1 enhancement pattern, but two had a type 2 pattern. Pathologically, each mass enhancement pattern had different tumor cell and matrix components. Warthin's tumor generally showed the type 4 pattern. Primary malignant tumors of the salivary gland all showed the type 3 pattern, and pathological specimens showed many tumor cells along the marginal portion of the tumor. One inflammatory cyst and one Warthin's tumor also showed the type 3 pattern. Except for metastatic renal cell carcinoma, the enhancement patterns of late phase images and dynamic study images were the same. CONCLUSIONS: Dynamic MRI added little diagnostic information about salivary gland masses, but the contrast-enhanced MR features correlated well with the pathological findings.

[Experiment in ultra-rapid injection of isotonic sodium chloride after injection of contrast medium: time-density analysis of the aorta and portal vein].

Ultra rapid injection of isotonic sodium chloride after the injection of contrast medium may make it possible to clearly distinguish between the arterial phase and the portal phase. This method could improve the detectability of hepatocellular carcinoma on double phase dynamic spiral CT. A time-density analysis of the aorta and the portal vein was carried out according to the following 2 protocols (5 cases each). In protocol 1, 95 ml of Iopamidol (300 mgI/ml) was injected at a rate of 3 ml/second, while the protocol 2, 40 ml of isotonic sodium chloride was injected at a rate of 10 ml/second after the injection of 60 ml of Iopamidol (300 mgI/ ml) at a rate of 10 ml/second. The duration of the arterial phase (aortic enhancement unit (EU) > or = 200) in protocol 2 was 11 seconds, which was shorter than that in protocol 1. In protocol 2, the duration of the clearly portal dominant phase (reversal phase; aortic EU < portal EU) was about 11 seconds.

[Age-related changes of diffusional anisotropy in the cerebral white matter in normal subjects].

To investigate age-related changes of diffusional anisotropy in the cerebral white matter, we performed diffusion-weighted MRI studies in 21 normal subjects aged 25 to 96 years. The anisotropic rations (ARs), defined as the apparent diffusion coefficients perpendicular to the nerve fibers to those parallel to the nerve fibers, were significantly higher in elderly than in young subjects in the anterior and posterior white matter surrounding the lateral ventricle. Moreover, significant correlation between age and AR was found in the anterior white matter. The ventricular index (VI) measured on MRI, as a quantitative indicator of brain atrophy, was significantly higher in elderly than younger subjects, and significantly correlated with AR in the anterior white matter. Multiple regression analysis demonstrated that the VI showed the highest correlation for AR. On the other hand, there was no significant correlations between ARs in the corpus callosum and age. These results suggest that morphological changes in the myelin and axon in the white matter occur in elderly normal subjects, probably due to neuronal loss with aging.

Increased water diffusion in cerebral white matter in Alzheimer's disease.

We investigated the changes in water diffusion in the cerebral white matter in 19 patients with Alzheimer's disease (AD), including 11 without and 8 with periventricular hyperintensity (PVH) lesions, using diffusion-weighted magnetic resonance imaging (MRI). The apparent diffusion coefficients in the anterior and posterior white matter were significantly higher in the 19 AD patients than in the 10 age-matched controls. The apparent diffusion coefficients were higher in patients with PVH than in those without. The anisotropic ratios, defined as diffusion restricted perpendicular to the direction of the nerve fibers, were significantly higher in AD patients, even in those without PVH, than in the controls. Our results suggest that mild myelin loss occurs in AD patients even in the apparently normal white matter. A definite loss of myelin and axons, including incomplete infarction, occurs in the white matter, as seen on T2-weighted images as PVH. Studies with diffusion-weighted MRI may allow the characterization of different pathological processes and enable the demonstration of underlying white matter lesions in AD that cannot be visualized by conventional MRI.

[Diffusional anisotropy in cerebral white matter in patients with dementia].

We studied changes in water diffusion in cerebral white matter in 10 patients with Binswanger's disease (BD), 8 patients with Alzheimer's disease (AD) who had periventricular hyperintensity lesions on T2-weighted images, and 8 age-matched controls. The apparent diffusion coefficients measured in the anterior and posterior white matter were significantly higher in the patients than in the controls, but there was no significant difference between patients with BD and those with AD. The anisotropy ratios, difined as diffusion perpendicular to the nerve fiber direction, were higher in the patients than in the controls. The anisotropy ratio in the anterior white matter was significantly higher in patients with BD than in those with AD, while in the posterior white matter the ratio was significantly higher in patients with AD than in those with BD. These results suggest that in BD and AD cerebral white matter lesions such as periventricular hyperintensity lesions reflect a loss of myelin and axons, and that loss of myelin occurs preferentially in the anterior white matter in BD and in the posterior white matter in AD.

[Diffusional anisotropy in the cerebral white matter in Alzheimer-type dementia].

To investigate changes in water diffusion in the cerebral white matter in Alzheimer-type dementia (AD), diffusion MRI studies were performed on 11 patients with AD without hyperintensity lesions on T2-weighted images, and 10 age-matched controls. In the anterior and posterior white matter around the lateral ventricule, and the splenium of the corpus callosum, the apparent diffusion coefficients (ADCs), in which the diffusion gradient was applied perpendicular to the predominant fiber direction, were significantly higher in patients with AD than in the controls. However, those in which the diffusion gradient was applied parallel to the predominant fiber direction, there were no significant difference in ADCs between patients and controls. Therefore, diffusional anisotropy was lost in the white matter. These results suggest that demyelination occurs in patients with AD even in apparently normal white matter (without signal abnormalitis). Degeneration related to grey matter encephalopathy may be a possible explanation of the demyelinating process in the white matter.

[MR diffusion-weighted imaging of cerebral infarction].

MR diffusion-weighted imaging was performed to investigate changes in water diffusion in patients with cerebral infarction, and diffusion-weighted images (DWI) were compared with T2-weighted images (T2WI). Acute and subacute infarcts were seen as areas of high intensity on DWI and showed lower apparent diffusion coefficients (ADCs), while chronic infarcts showed a relative increase in ADCs. The relative ADC increased progressively over time, becoming renormalized at 3 to 4 weeks, and was elevated in the chronic state. On DWI, infarcts as small as 5 to 6 mm in diameter and lesions adjacent to the ventricular or subarachnoid space could be readily identified. DWI was useful for distinguishing acute lesions from chronic lesions in patients with multiple cerebral infarction, and provided valuable pathophysiologic information on the course of ischemic stroke evolution.

[Diffusion MRI study of cerebral white matter lesions in patients with Binswanger's disease].

We performed diffusion MRI studies in 14 patients with extensive ischemic leukoencephalopathy, including 9 with dementia (diagnosed as Binswanger's disease), and 5 without dementia, and 8 age-matched controls. Apparent diffusion coefficients (ADCs) in anterior and posterior periventricular white matter were significantly higher in demented and non-demented patients than in the controls, and diffusion anisotropy disappeared in patients because of the high ratio of the diffusion coefficients perpendicular to the nerve fibers to those parallel to the nerve fibers. ADCs in the corpus callosum were significantly higher in demented patients that in non-demented patients and controls. Therefore, diffusion anisotropy disappeared only in demented (Binswanger's disease) patients. These results suggest that the cerebral white matter lesions in Binswanger's disease reflect a decrease of nerve fibers and diffuse myelin loss, and that the loss of nerve fibers in the corpus callosum may play a role in inducing cognitive decline. Diffusion MRI may be useful in the pathophysiological evaluation of cerebral white matter lesions.

CT scanning of bronchioloalveolar carcinoma: specific appearances.

We reviewed CT scans in 38 cases with pathologically proved bronchioloalveolar carcinoma. CT revealed three CT patterns: solitary, pneumonic and diffuse forms. The solitary pattern (22 patients) had a high percentage of air bronchograms (95%), pleural indentation (77%) and spiculation (68%). The pneumonia-like pattern (16 lesions in 10 patients) had air bronchograms in all cases (100%), low attenuation (88%) and protrusion of interlobar fissures (63%). The diffuse form (six patients) had 2 or 3 mm diffuse small nodules scattered throughout the entire lung. CT of bronchioloalveolar carcinoma revealed many findings and was useful in recognizing the tumor distribution and extent. We conclude that CT is helpful for the diagnosis and evaluation of bronchioloalveolar carcinoma.

[Detection of cortical infarcts in brain MR imaging: feasibility of short-TR-T2-weighted imaging using a fast spin echo sequence].

MRI of the brain using a fast SE sequence is often performed with a TR above 5000 msec, so there is a tendency for the signal of CSF to become too high. However, when cerebral atrophy is marked, small lesions of the brain parenchyma can be hard to detect. Therefore, we examined short-TR-T2-weighted images using a fast spin echo sequence. The 58 subjects included 33 men and 25 women, and cortical infarction was detected in five of them. On the short-TR-T2WI sequences, the infarct lesions were imaged as areas of higher signal intensity than cerebrospinal fluid, the signal of which was reduced. In cortical infarction cases, fluid-attenuated inversion recovery (FLAIR) images can detect the lesion more easily, but FLAIR sequences cannot be obtained with all MR equipment. Short-TR-T2WI, which readily yields images comparable to those of FLAIR, is an useful method.