Precursor-free eruption triggered by edifice rupture at Nyiragongo volcano.

Classical mechanisms of volcanic eruptions mostly involve pressure buildup and magma ascent towards the surface1. Such processes produce geophysical and geochemical signals that may be detected and interpreted as eruption precursors1-3. On 22 May 2021, Mount Nyiragongo (Democratic Republic of the Congo), an open-vent volcano with a persistent lava lake perched within its summit crater, shook up this interpretation by producing an approximately six-hour-long flank eruption without apparent precursors, followed-rather than preceded-by lateral magma motion into the crust. Here we show that this reversed sequence was most likely initiated by a rupture of the edifice, producing deadly lava flows and triggering a voluminous 25-km-long dyke intrusion. The dyke propagated southwards at very shallow depth (less than 500 m) underneath the cities of Goma (Democratic Republic of the Congo) and Gisenyi (Rwanda), as well as Lake Kivu. This volcanic crisis raises new questions about the mechanisms controlling such eruptions and the possibility of facing substantially more hazardous events, such as effusions within densely urbanized areas, phreato-magmatism or a limnic eruption from the gas-rich Lake Kivu. It also more generally highlights the challenges faced with open-vent volcanoes for monitoring, early detection and risk management when a significant volume of magma is stored close to the surface.

Crustal seismic velocity responds to a magmatic intrusion and seasonal loading in Iceland's Northern Volcanic Zone.

Seismic noise interferometry is an exciting technique for studying volcanoes, providing a continuous measurement of seismic velocity changes (dv/v), which are sensitive to magmatic processes that affect the surrounding crust. However, understanding the exact mechanisms causing changes in dv/v is often difficult. We present dv/v measurements over 10 years in central Iceland, measured using single-station cross-component correlation functions from 51 instruments across a range of frequency bands. We observe a linear correlation between changes in dv/v and volumetric strain at stations in regions of both compression and dilatation associated with the 2014 Bárðarbunga-Holuhraun dike intrusion. Furthermore, a clear seasonal cycle in dv/v is modeled as resulting from elastic and poroelastic responses to changing snow thickness, atmospheric pressure, and groundwater level. This study comprehensively explains variations in dv/v arising from diverse crustal stresses and highlights the importance of deformation modeling when interpreting dv/v, with implications for volcano and environmental monitoring worldwide.

Comparison of Coxiella burnetii shedding in milk of dairy bovine, caprine, and ovine herds.

The shedding of Coxiella burnetii in bovine, caprine, and ovine milk was measured using PCR, in 3 herds for each species, the bulk tank milk samples of which were positive at the time of their selection. Milk samples of 95 cows, 120 goats, and 90 ewes were sampled over 16 wk, as was the bulk tank milk. The shedding of C. burnetii in vaginal mucus and feces was checked at the beginning of the experiment and 2 mo later. The clinical signs in the selected herds as well as the duration and the shedding routes differed among the 3 species. The cows were asymptomatic and shed C. burnetii almost exclusively in milk. In one of the caprine herds, abortions due to C. burnetii were reported. The goats excreted the bacteria mainly in milk. In contrast, the ewes, which came from flocks with abortions due to Q fever (C. burnetii infection), shed the bacteria mostly in feces and in vaginal mucus. This could explain why human outbreaks of Q fever are more often related to ovine flocks than to bovine herds. These excretions did not seem more frequent when the samples were taken close to parturition. The samples were taken from 0 to 421 d after parturition in bovine herds and from 5 to 119 d and 11 to 238 d after parturition in the caprine and ovine herds, respectively. The shedding in milk was sometimes intermittent, and several animals shed the bacteria but were negative by ELISA: 80% of the ewes were seronegative, underscoring the lack of sensitivity of the ELISA tests available for veterinary diagnosis. The detection of antibodies in milk seems more sensitive than it is in serum.

[Ganglion cyst at the spinoglenoid notch. A case report and literature review]. / Kyste du défilé spinoglénoïdien. A propos d'un cas et revue de la littérature.

INTRODUCTION: Entrapment of the suprascapular nerve at the spinoglenoid notch due to a ganglion cyst is an uncommon event and remains a challenge for clinicians. EXEGESIS: We describe the findings in a 35-year-old patient with nonspecific pain in the shoulder and in whom MR revealed a ganglion cyst in the spinoglenoid notch, confirmed surgically. CONCLUSION: Entrapment of the suprascapular nerve at the spinoglenoid notch due to a ganglion cyst must be considered in the differential diagnosis of nonspecific shoulder pain. MR imaging and electromyography can reach a positive, topographic, and etiologic diagnosis of suprascapular neuropathy.

[Vitrectomy without scleral buckle versus ab-externo approach for pseudophakic retinal detachment: comparative retrospective study]. / Traitement du décollement de rétine du pseudophaque: étude rétrospective comparant la vitrectomie sans indentation au traitement ab-externo.

PURPOSE: Retinal detachment (RD) is a major complication of cataract surgery, which can be treated by either primary vitrectomy without indentation or the scleral buckling procedure. The aim of this study is to compare the results of these two techniques for the treatment of pseudophakic RD. PATIENTS AND METHODS: The charts of 40 patients (40 eyes) treated with scleral buckling for a primary pseudophakic RD were retrospectively studied and compared to the charts of 32 patients (32 eyes) treated with primary vitrectomy without scleral buckle during the same period by the same surgeons. To obtain comparable samples, patients with giant retinal tears, vitreous hemorrhage, and severe preoperative proliferative vitreoretinopathy (PVR) were not included. Minimal follow-up was 6 months. RESULTS: The primary success rate was 84% in the vitrectomy group and 82.5% in the ab-externo group. Final anatomical success was observed in 100% of cases in the vitrectomy group and in 95% of cases in the ab-externo group. Final visual acuity was 0.5 or better in 44% of cases in the vitrectomy group and 37.5% in the ab-externo group. The duration of the surgery was significantly lower in the ab-externo group, whereas the hospital stay tended to be lower in the vitrectomy group. In the vitrectomy group, postoperative PVR developed in 3 eyes and new or undetected breaks were responsible for failure of the initial procedure in 2 eyes. CONCLUSION: Primary vitrectomy appears to be as effective as scleral buckling procedures for the treatment of pseudophakic RD.

Adventitial sheathotomy for decompression of recent onset branch retinal vein occlusion.

UNLABELLED: Interesting results have been reported on the use of pars plana vitrectomy with adventitial sheathotomy for the decompression of branch retinal vein occlusions (BRVO). Recent onset BRVO responsible for a visual acuity of 20/40 or less have been estimated to be good candidates for this procedure. We report on the results of the prospective evaluation of three eyes (in three patients) with recent onset BRVO which underwent surgical decompression. Three men, aged 40, 50, and 68 years presenting with BRVO for 4, 4, and 3 weeks respectively, underwent surgical decompression. Initial visual acuity was 20/80, 20/80, and 20/200. After 11, 10, and 9 months follow-up, visual acuity was 20/80, 20/200, and 20/200. In two eyes, an increase of the area of retinal non-perfusion was treated with peripheral laser photocoagulation. No cataract, retinal tears or retinal detachment were observed. CONCLUSION: although feasible, sheathotomy did not lead to a significant visual improvement in our patients. Dissection of the arteriovenous crossing could have induced vascular trauma. Furthermore, vitrectomy with posterior hyaloid detachment alone could be of benefit in the treatment of branched retinal vein occlusions. A prospective randomised trial is needed to assess the effectiveness and the safety of this procedure and to determine the best candidates for surgery.

Mesoinnominate shunt for the treatment of Budd-Chiari syndrome: evaluation with multimodality imaging.

The construction of a mesoinnominate shunt between the superior mesenteric vein and the left innominate vein is a recent surgical procedure for the treatment of Budd-Chiari syndrome with vena caval obstruction. The purpose of this study was to determine the role of the different imaging modalities for the follow-up of mesoinnominate shunts. Doppler US (n = 32), and MR imaging examinations (n = 32) were prospectively performed in 10 patients with mesoinnominate shunts. Shunt patency or thrombosis was confirmed with angiography (n = 32) and transhepatic portography with pressure measurement (n = 6). For each follow-up evaluation, all examinations were performed within 4 days. Shunt patency was correctly demonstrated in 28/28 cases with Doppler US, CT and MR imaging. Shunt thrombosis was correctly demonstrated in 4/4 cases with Doppler US, CT and MR imaging. Since Doppler US, CT and MR imaging have the same accuracy for diagnosing mesoinnominate shunt patency and detecting thrombosis, our study suggests that redundant screening methods can be avoided. Doppler US is accurate enough and should be the preferred technique in the evaluation of mesoinnominate shunts.

MRI of adenomatous hyperplastic nodules of the liver in Budd-Chiari syndrome.

We present two cases of adenomatous hyperplastic nodules (AHN) occurring in patients with chronic Budd-Chiari syndrome who were investigated with MRI. In one case the foci of AHN were isointense to the liver on spin echo (SE) T1-weighted MRI and were hyperintense on both SE proton density and SE T2-weighted MRI. In the other case the nodules were hyper-intense on SE T1-weighted MRI. They were isointense on SE proton density-weighted MRI and became slightly hyperintense on SE T2-weighted MRI. Furthermore, in both cases one nodule displayed hyperintensity with hypointense rims on SE T2-weighted MRI.

MRI of liver metastases from colorectal cancer vs. CT during arterial portography.

A prospective study was performed to compare, with a lesion-by-lesion analysis, the sensitivities of high field strength MRI and CT during arterial portography (CTAP) in detecting hepatic metastases from colorectal cancer. Twenty-one patients with liver metastases from colorectal cancer were prospectively investigated by high field strength MRI (1.5 or 2 T) and CTAP. High field strength MRI was performed with pre and post gadopentetate dimeglumine enhanced T1-weighted SE sequences and T2-weighted SE sequences. All patients underwent partial hepatectomy and 37 metastases were surgically and pathologically proved. The metastasis detection rate (sensitivity) was 94% (35 of 37) for CTAP and 78% (29 of 37) for high field strength MRI. The 16% (95% confidence interval: 1-31%) difference in sensitivity between CTAP and high field strength MRI was statistically significant (p < 0.05, McNemar test). The use of gadopentetate dimeglumine did not improve the sensitivity of T1-weighted SE sequences. Since our study demonstrated significant difference in sensitivities between high field strength MRI and CTAP in our group of patients, we can conclude that high field strength MRI cannot replace CTAP in the preoperative evaluation of patients with liver metastases from colorectal cancer. Computed tomography during arterial portography must be considered as the preoperative gold standard.

[Zollinger-Ellison syndrome of ovarian origin. Apropos of a case with a review of the literature]. / Syndrome de Zollinger-Ellison d'origine ovarienne. A propos d'un cas avec revue de la littérature.

We report a case of Zollinger-Ellison syndrome due to secretory G and D cells in an ovarian mucinous cystadenoma. Surgical resection of the tumour led to disappearance of clinical symptomatology and laboratory signs. Four other cases were found in the literature. The prognosis of the Zollinger-Ellison syndrome, due to a secretory ovarian tumour, appears to be favourable after oophorectomy.

Lateral discoid menisci in children.

In children, the snapping-knee syndrome is strongly suggestive of a diagnosis of discoid menisci; alternatively, the loss of physiological hyperextension of the knee suggests a diagnosis of a torn lateral discoid meniscus. We used arthroscopic meniscectomy to treat 19 lateral discoid menisci in 16 children (average age, 10.5 years). Excellent results were achieved in 18 of 19 cases, with disappearance of the snapping with knee flexion (maximum follow-up, 3 years).