Detecting immunoglobulin G4-related intracranial arteriopathy with magnetic resonance vessel wall imaging: a preliminary experience in two cases

[Background] Detecting immunoglobulin G4 (IgG4)-related intracranial arteriopathy, a rare neurovascular complication of IgG4-related disease, is challenging. While magnetic resonance (MR) vessel wall imaging (VWI) can visualize various neurovascular pathologies, its application to this arteriopathy has not been reported as of this writing. [Case presentation] A 74-year-old male and a 65-year-old female manifested multiple cranial nerve palsy and neck pain, respectively. Both cases exhibited multiorgan masses with markedly elevated serum IgG4 levels and were clinically diagnosed with IgG4-related disease. Three-dimensional T1-weighted black blood VWI with and without contrast agent identified intracranial vascular lesions characterized as nearly-circumferential mural thickening with homogeneous contrast enhancement in the internal carotid and vertebral arteries; some of the lesions had been unrecognized with screening MR angiography due to expansive remodeling. The former patient underwent corticosteroid therapy, and VWI after treatment revealed decreased mural thickening and enhancement. [Conclusion] Further studies to elucidate characteristic findings of VWI might contribute to early detection of this treatable pathology

The clinical features of pulmonary artery involvement in Takayasu arteritis and its relationship with ischemic heart diseases and infection

BACKGROUND: Pulmonary artery involvement (PAI) in Takayasu arteritis (TAK) can lead to severe complications, but the relationship between the two has not been fully clarified. METHODS: We retrospectively investigated 166 consecutive patients with TAK who attended Kyoto University Hospital from 1997 to 2018. The demographic data, clinical symptoms and signs, comorbidities, treatments, and imaging findings were compared between patients with and without PAI. TAK was diagnosed based on the American College of Rheumatology Classification Criteria (1990) or the Japanese Clinical Diagnostic Criteria (2008). PAI was identified using enhanced computed tomography, magnetic resonance imaging, or lung scintigraphy. RESULTS: PAI was detected in 14.6% (n = 24) of total TAK patients. Dyspnea (25.0% vs. 8.6%; p = 0.043), pulmonary arterial hypertension (PAH) (16.7% vs. 0.0%; p < 0.001), ischemic heart disease (IHD) (29% vs. 9.3%; p = 0.018), respiratory infection (25.0% vs. 6.0%; p = 0.009), and nontuberculous mycobacteria (NTM) infection (20.8% vs. 0.8%; p < 0.001) were significantly more frequent, and renal artery stenosis (0% vs. 17%; p = 0.007) was significantly less frequent in TAK patients with PAI than in those without PAI. PAI and biologics were risk factors for NTM. CONCLUSIONS: TAK patients with PAI more frequently have dyspnea, PAH, IHD, and respiratory infection, including NTM, than TAK patients without PAI

Seismic Exploration Using Active Sources at Kuchierabujima Volcano, Southwest Japan

Seismic exploration using artificial sources was conducted at Kuchierabujima volcano, southwest Japan in November 2004 by 40 participants from 9 national universities andJapan Meteorological Agency to investigate the subsurface seismic structure. The exploration was the 11th joint experiment under the National Project for Prediction of Volcanic Eruptions. A total of 183 temporal stations equippedwith a 2 Hz vertical component seismometer (including 75 3component seismometers) and a portable data logger were deployed on Kuchierabu Island. Dynamite shots with charges of 10-115 kg were detonated at 19 locations, and seismic signals were successfully recorded. To reveal the P-wave velocity structure, 2955 arrival times of the first motion were picked from the seismograms, and 2187 were classified into ranks A and B. From the record sections and the arrival time data, characteristics reflecting the geological structure were identified. Refracted waves of 5 km/s were observed at stations＞5km from the shot points. Apparent velocities near the shot points depend on the surface geology around the shots. P-wave arrived earlier at stations near the summits. Strongly scattered waves were observed similarly near the summits

Seismic exploration at Fuji volcano with active sources : The outline of the experiment and the arrival time data

Fuji volcano (altitude 3,776m) is the largest basaltic stratovolcano in Japan. In late August and early September 2003, seismic exploration was conducted around Fuji volcano by the detonation of 500 kg charges of dynamite to investigate the seismic structure of that area. Seismographs with an eigenfrequency of 2 Hz were used for observation, positioned along a WSW-ENE line passing through the summit of the mountain. A total of 469 seismic stations were installed at intervals of 250-500 m. The data were stored in memory on-site using data loggers. The sampling interval was 4 ms. Charges were detonated at 5 points, one at each end of the observation line and 3 along its length. The first arrival times and the later-phase arrival times at each station for each detonation were recorded as data. P-wave velocities in the surface layer were estimated from the travel time curves near the explosion points, with results of 2.5 km/s obtained for the vicinity of Fuji volcano and 4.0 km5/s elsewhere

Inter-eruptive volcanism at Usu volcano : Micro-earthquakes and dome subsidence

Post-eruptive crustal activity after the 2000 eruption of Usu volcano was investigated by seismic and geodetic field observations. Remarkable features of the magmatic eruptions that occur almost every 30 years include lava dome formation and strong precursory earthquakes. On the other hand, rapid dome subsidence was observed by electronic distance meter (EDM) measurement after the 1977-1982 summit eruption. Since the 2000 eruption, seismic activity at a shallow part under the summit crater has remained at a high level relative to that after the 1977-1982 eruption, although eruption occurred at the western foot of the volcano during the 2000 eruption. To reveal the shallow crustal activity in the inter-eruptive period around the summit area, seismicity and crustal deformation have been investigated since 2006. Dense temporary seismic observations and hypocenter relocation analysis using a three-dimensional velocity structure model revealed that the focal area is localized along the U-shaped fault that developed in the dome-forming stage of the 1977-1982 eruption. Three major focal clusters are distributed on the southwestern side of Usu-Shinzan cryptodome, which was built up during the 1977-1982 eruption. For the seven major events with magnitudes larger than 1, the focal mechanism was a large dip-slip component, which suggests the subsidence of Usu-Shinzan cryptodome. Interferomatetric satellite aperture radar (InSAR) image analysis and repeated GPS measurements revealed subsidence of the summit dome, which is almost centered at the Usu-Shinzan cryptodome. The area of rapid deformation is restricted to a small area around the summit crater. The estimated rate of dome subsidence relative to the crater floor is about 3 cm/year. These results strongly suggest that subsidence of Usu-Shinzan is associated with the small earthquakes along the U-shaped fault that surrounds the cryptodome. According to prior seismic and geodetic studies, it is thought that most of the magma rising under the summit crater during the 2000 eruption stopped around a depth of 2 km below sea level, which is sufficiently deep relative to the focal area of the present seismicity. A part of magma intruded under the western foot and contributed to the 2000 eruption. We conclude that the 2000 eruption scarcely affected the shallow crustal activity under the summit crater, and that Usu-Shinzan cryptodome is continuing to subside just as it was before the 2000 eruption. The shallow volcanic earthquakes that began increasing from 1995 are closely related to the successive subsidence of the summit domes. Temporal change in fumarole temperature suggests a relationship between the shallow earthquakes and cooling of the magma that intruded under Usu-Shinzan during the 1977-1982 eruption