Dexamethasone blocks the systemic inflammation of alveolar hypoxia at several sites in the inflammatory cascade.

Alveolar hypoxia produces a rapid and widespread systemic inflammation in rats. The inflammation is initiated by the release into the circulation of monocyte chemoattractant protein-1 (MCP-1) from alveolar macrophages (AMO) activated by the low alveolar Po(2). Circulating MCP-1 induces mast cell (MC) degranulation with renin release and activation of the local renin-angiotensin system, leading to microvascular leukocyte recruitment and increased vascular permeability. We investigated the effect of dexamethasone, a synthetic anti-inflammatory glucocorticoid, on the development of the systemic inflammation of alveolar hypoxia and its site(s) of action in the inflammatory cascade. The inflammatory steps investigated were the activation of primary cultures of AMO by hypoxia, the degranulation of MCs by MCP-1 in the mesentery microcirculation of rats, and the effect of angiotensin II (ANG II) on the leukocyte/endothelial interface of the mesentery microcirculation. Dexamethasone prevented the mesentery inflammation in conscious rats breathing 10% O(2) for 4 h by acting in all key steps of the inflammatory cascade. Dexamethasone: 1) blocked the hypoxia-induced AMO activation and the release of MCP-1 and abolished the increase in plasma MCP-1 of conscious, hypoxic rats; 2) prevented the MCP-1-induced degranulation of mesentery perivascular MCs and reduced the number of peritoneal MCs, and 3) blocked the leukocyte-endothelial adherence and the extravasation of albumin induced by topical ANG II in the mesentery. The effect at each site was sufficient to prevent the AMO-initiated inflammation of hypoxia. These results may explain the effectiveness of dexamethasone in the treatment of the systemic effects of alveolar hypoxia.

Compliance Issues in Managing 21 Hydroxylase Deficiency and their Short/Long-Term Consequences.

OBJECTIVE: To report a case of untreated classic 21 hydroxylase (OH) deficiency congenital adrenal hyperplasia (CAH) in a transgender patient resulting in pulmonary embolisms (PEs) and bilateral adrenal masses. METHODS: A 36-year-old male (birth sex: female) presenting with bilateral PEs in the setting of long-standing, untreated classic 21OH CAH was also found to have bilateral adrenal masses (unconfirmed myelolipomas). RESULTS: Further history revealed a known diagnosis of CAH. The patient had been treated with glucocorticoid and mineralocorticoid replacement in childhood but stopped taking these medications against medical advice. During his hospital admission, he was noted to have elevated 17-hydroxyprogesterone, low cortisol with elevated ACTH levels, and male-level testosterone measurements. CT of the abdomen/pelvis revealed a 23 cm mass in the left renal fossa and a 2.5 cm mass in the right renal fossa consistent with bilateral adrenal myelolipomas. The patient attended follow-up in clinic, but declined any further hormonal treatment as he identified as male and felt further treatment was unnecessary. CONCLUSION: This case demonstrated the unique long-term effects of untreated classic CAH due to 21OH deficiency, including bilateral adrenal myelolipoma, adrenal compensation to the point of producing male-level androgens, and possibly PEs. Treatment with hydrocortisone was recommended to suppress ACTH and it was planned that the patient would eventually start on testosterone (although this would have been complicated by his bilateral PEs). Potential aetiologies for the PEs included vascular compression of the renal artery (which could explain the elevated EPO/erythrocytosis contributing to hypercoagulability) or the renal vein by the adrenal mass. LEARNING POINTS: Gender dysphoria in patients with congenital adrenal hyperplasia (CAH) is not uncommon.Adrenal enlargement can allow untreated CAH patients to compensate.Pulmonary embolisms can be a consequence of treating as well as untreated CAH.

Practical Considerations for Clinical PET/MR Imaging.

Clinical PET/MR imaging is currently performed at a number of centers around the world as part of routine standard of care. This article focuses on issues and considerations for a clinical PET/MR imaging program, focusing on routine standard-of-care studies. Although local factors influence how clinical PET/MR imaging is implemented, the approaches and considerations described here intend to apply to most clinical programs. PET/MR imaging provides many more options than PET/computed tomography with diagnostic advantages for certain clinical applications but with added complexity. A recurring theme is matching the PET/MR imaging protocol to the clinical application to balance diagnostic accuracy with efficiency.

Role of lower extremity run-off CT angiography in the evaluation of acute vascular disease.

In the acute care setting, radiologists are frequently asked to assist in the evaluation of patients presenting with signs and symptoms of lower extremity peripheral vascular disease. Non-traumatic peripheral vascular emergencies are most commonly the result of thrombosis, either in a native vessel or within a bypass graft or stent. Arterial emboli, peripheral aneurysm with embolus or thrombosis, and direct arterial trauma are additional, less common causes. Traumatic peripheral vascular emergencies include vessel occlusion, transection, pseudoaneurysms, active extravasation, and arteriovenous fistulas. The high morbidity and mortality associated with acute limb ischemia makes rapid diagnosis and early initiation of therapy critical in the management of such patients. Computed tomographic angiography (CTA) offers the vascular specialist a rapid, widely available, and accurate means to diagnose and grade the extent of vascular disease in the acute care setting. In this pictorial essay, the key elements of lower extremity run-off CTA are reviewed, including relevant anatomy, imaging approach, and spectrum of imaging findings.

Magnetic resonance imaging of first trimester pregnancy: expected intrauterine contents in relation to gestational age.

PURPOSE: To determine if and when fetal structures are identifiable during first trimester pregnancy on magnetic resonance imaging (MRI) in women with acute abdominopelvic pain. METHODS: Sixty-four first trimester MRI examinations performed for evaluation of abdominopelvic pain were reviewed retrospectively. T2-weighted images were assessed independently by three radiologists for the presence of gestational sac, yolk sac, fetal pole, and limb buds. Mean sac diameter and sac volume were determined, and logistic regression analyses were performed. Criterion values for fetal structures and gestational sac size were calculated using receiver operating characteristic analysis. RESULTS: A gestational sac is present in all but two cases. The yolk sac is never identified. A fetal pole is identified at a gestational age (GA), mean sac diameter (MSD), and gestational sac volume (GSV) of greater than 6.4 weeks, 1.7 cm, and 8.9 mL, respectively. Limb buds are identified at a GA, MSD, and GSV of greater than 8.1 weeks, 3.4 cm, and 27.1 mL, respectively. There is a significant correlation between GA and gestational sac size, including the MSD (r 2 = 0.85, P < 0.01) and GSV (r 2 = 0.86, P < 0.01). CONCLUSIONS: The gestational sac is readily demonstrated on T2-weighted images, but the yolk sac is not identified on routine MRI. The fetal pole and limb buds are seen on MRI at a similar GA and MSD as with published values using transvaginal sonography.

Practical Considerations for Clinical PET/MR Imaging.

Clinical PET/MR imaging is currently performed at a number of centers around the world as part of routine standard of care. This article focuses on issues and considerations for a clinical PET/MR imaging program, focusing on routine standard-of-care studies. Although local factors influence how clinical PET/MR imaging is implemented, the approaches and considerations described here intend to apply to most clinical programs. PET/MR imaging provides many more options than PET/computed tomography with diagnostic advantages for certain clinical applications but with added complexity. A recurring theme is matching the PET/MR imaging protocol to the clinical application to balance diagnostic accuracy with efficiency.