Distal insertion of the clavicular portion of pectoralis major muscle: anatomical study

PURPOSE

Several descriptions of the anatomy of the pectoralis major (PM) have been published. However, the precise description of its distal humeral insertion, which is involved in traumatic tears, remains controversial. The distal tendon is classically described as being made of two layers, one anterior (ALPM) and one posterior (PLPM), which regroup at their distal edge. The clavicular head (CH) participates in the ALPM according to most authors. However, others describe a more superficial termination in a close relationship with the deltoid humeral insertion. The objective of this anatomical work is to precisely describe the anatomy of the CH and its relationship with the rest of the distal PM tendon and the distal deltoid tendon.

MATERIALS

Twenty-three fresh cadaveric specimens were dissected (41 shoulders). The entire PM as well as the deltoid were exposed. Several measurements were collected to establish the relationships between the distal tendon of the CH and the PM, the deltoid and the bony landmarks.

RESULTS

In all cases, the CH muscular portion sits on the ALPM but does not participate in the connective structure of the PM distal tendon. The inferolateral part of its distal end gives a thin tendinous portion that inserts lower on the humerus in conjunction with the distal tendon of the deltoid. In 24.4%, this tendon was more difficult to isolate but was always observed.

CONCLUSIONS

The distal tendon of the PM only comes from the muscle fibres of its sternal head. The CH fibres do not contribute to this tendon but appear to terminate in a separate tendon fusing with the humeral insertion of the deltoid: the deltopectoral tendon. This could explain the different patterns of tears observed in clinical practice.

Contrast enhancement early after renal malignancy cryoablation: imaging findings associated with benignity

OBJECTIVES

Contrast enhancement by MRI done early after cryoablation for renal malignancies may suggest residual tumor (RT). However, we have observed MRI enhancement within 48 h of cryoablation in patients who had no contrast enhancement 6 weeks later. Our purpose was to identify features of 48-h contrast enhancement in patients without RT.

METHODS

This single-center retrospective study included consecutive patients who underwent percutaneous cryoablation of renal malignancies in 2013-2020, exhibited cryoablation-zone MRI contrast enhancement 48 h later, and had available 6-week MRI scans. Persistent or growing CE at 6 weeks vs. 48 h was classified as RT. A washout index was calculated for each 48-h MRI, and its performance for predicting RT was assessed by receiver operating characteristic curve analysis.

RESULTS

We included 60 patients with 72 cryoablation procedures and 83 cryoablation zones exhibiting 48-h contrast enhancement; mean age was 66 ± 17 years. Clear-cell renal cell carcinoma accounted for 95% of tumors. Of the 83 48-h enhancement zones, RT was observed in eight while 75 were benign. The 48-h enhancement was consistently visible at the arterial phase. Washout was significantly associated with RT (p < 0.001) and gradually increasing contrast enhancement with benignity (p < 0.009). A washout index below  - 1.1 predicted RT with 88% sensitivity and 84% specificity.

CONCLUSION

MRI contrast enhancement 48 h after cryoablation of renal malignancies was usually benign. Washout was associated with residual tumor, with a washout index value below  - 1.1 exhibiting good performance in predicting residual tumor. These findings may help to guide decisions about repeat cryoablation.

CLINICAL RELEVANCE STATEMENT

Magnetic resonance imaging contrast enhancement 48 h after cryoablation of renal malignancies rarely indicates residual tumor, which is characterized by washout with a washout index lower than  - 1.1.

KEY POINTS

• Contrast enhancement at the arterial phase of magnetic resonance imaging done 48 h after cryoablation of a renal malignancy is usually benign. • Residual tumor manifesting as contrast enhancement at the arterial phase is characterized by subsequent marked washout. • A washout index below  - 1.1 has 88% sensitivity and 84% specificity for residual tumor.

Benefit of mechanical thrombectomy in acute ischemic stroke related to calcified cerebral embolus

PURPOSE

Mechanical thrombectomies (MT) in patients with large vessel occlusion (LVO) related to calcified cerebral embolus (CCE) have been reported, through small case series, being associated with low reperfusion rate and worse outcome, compared to regular MT. The purpose of the MASC (Mechanical Thrombectomy in Acute Ischemic Stroke Related to Calcified Cerebral Embolus) study was to evaluate the incidence of CCEs treated by MT and the effectiveness of MT in this indication.

METHODS

The MASC study is a retrospective multicentric (n = 37) national study gathering the cases of adult patients who underwent MT for acute ischemic stroke with LVO related to a CCE in France from January 2015 to November 2019. Reperfusion rate (mTICI ≥ 2B), complication rate and 90-day mRS were systematically collected. We then conducted a systematic review by searching for articles in PubMed, Cochrane Library, Embase and Google Scholar from January 2015 to March 2020. A meta-analysis was performed to estimate clinical outcome at 90 days, reperfusion rate and complications.

RESULTS

We gathered data from 35 patients. Reperfusion was obtained in 57% of the cases. Good clinical outcome was observed in 28% of the patients. The meta-analysis retrieved 136 patients. Reperfusion and good clinical outcome were obtained in 50% and 29% of the cases, respectively.

CONCLUSION

The MASC study found worse angiographic and clinical outcomes compared to regular thrombectomies. Individual patient-based meta-analysis including the MASC findings shows a 50% reperfusion rate and a 29% of good clinical outcome.

Precocious puberty related to Leydig cell testicular tumor: the diagnostic imaging keys

BACKGROUND

We report the challenging case of a 6-year-old boy with precocious puberty related to histologically proven Leydig cell tumor.

CASE PRESENTATION

Multiparametric ultrasound and magnetic resonance imaging (MRI) was performed. Interesting findings were scarcely or never reported in children and differed from adults Leydig cell tumors s such as the hyperechogenic halo surrounding the lesion and the dominant central vascularization using ultrasensitive Doppler. MRI revealed an enlarged testicle with strong enhancement of a tumor, a tumor apparent diffusion coefficient (ADC) of 600 × 10-3 mm2/s and a lower ADC value of the non-tumor parenchyma compared to the contralateral testis (ADC = 800 × 10-3 mm2/s vs 1100 × 10-3 mm2/s), attributed to the spermatogenesis induced by hormonal impregnation.

CONCLUSION

We illustrate multiparametric US and MRI findings of a pediatric Leydig cell tumor, including the imaging changes attributed to local hormone secretion, which may be helpful in similar cases.

Clinical Characteristics, Angioarchitecture and Management of Tectum Mesencephali Arteriovenous Malformations : A Retrospective Case Series

PURPOSE

Tectum mesencephali arteriovenous malformations (TM-AVMs) are rare lesions deeply located close to eloquent structures making them challenging to treat. We aimed to present clinical presentation, angiographic features and treatment strategies of TM-AVMs through a single center retrospective case series.

METHODS

A TM-AVMs is defined as a nidus located in the parenchyma or on the pia mater of the posterior midbrain. Records of consecutive patients admitted with TM-AVMs over a 21-year period were retrospectively analyzed. Vascular anatomy of the region is also reviewed.

RESULTS

In this study 13 patients (1.63% of the complete cohort; 10 males), mean age 48 years, were included. All patients presented with intracranial hemorrhage and two patients (15%) died after an early recurrent bleeding. Mean size of the TM-AVMs was 10.1 ± 5 mm. Multiple arterial feeders were noted in every cases. Of the patients 11 underwent an exclusion treatment, 8 via embolization (6 via arterial access and 2 via venous access) and 4 via stereotactic radiosurgery (SRS) (1 patient received both). Overall success treatment rate was 7/11 patients (64% overall; 63% in the embolization group, 25% in the SRS group). Two hemorrhagic events led to a worsened outcome, one during embolization and one several years after SRS. All other patients remained clinically stable or improved.

CONCLUSION

The TM-AVMs are rare but stereotypic lesions found in a hemorrhagic context. Multiple arterial feeders are always present. Endovascular treatment seems to be an effective technique with relatively low morbidity; SRS had a low success rate but was only use in a limited number of patients.

Control of aversion by glycine-gated GluN1/GluN3A NMDA receptors in the adult medial habenula

The unconventional N-methyl-d-aspartate (NMDA) receptor subunits GluN3A and GluN3B can, when associated with the other glycine-binding subunit GluN1, generate excitatory conductances purely activated by glycine. However, functional GluN1/GluN3 receptors have not been identified in native adult tissues. We discovered that GluN1/GluN3A receptors are operational in neurons of the mouse adult medial habenula (MHb), an epithalamic area controlling aversive physiological states. In the absence of glycinergic neuronal specializations in the MHb, glial cells tuned neuronal activity via GluN1/GluN3A receptors. Reducing GluN1/GluN3A receptor levels in the MHb prevented place-aversion conditioning. Our study extends the physiological and behavioral implications of glycine by demonstrating its control of negatively valued emotional associations via excitatory glycinergic NMDA receptors.