How to avoid pitfalls in interpretation of adrenal imaging

By Philip Ward, AuntMinnieEurope.com staff writer

January 15, 2019 — A clear understanding of the pitfalls in the performance and interpretation of adrenal CT can help prevent incorrect and inappropriate investigations, award-winning researchers from a top London facility have found. It’s essential to keep aware of the full range of pseudolesions and mimics, they said.

“Evaluation of adrenal tumor function is limited on imaging, but may be inferred from imaging findings,” noted Dr. Gurinder Nandra and colleagues from the department of radiology at St. George’s University Hospitals NHS Foundation Trust in an e-poster presentation that received a cum laude award at RSNA 2018 in Chicago.

Other adrenal pathology, including metastases and adrenocortical carcinoma, may be encountered, and this means it’s important to know about the imaging approaches to evaluate the adrenals, the authors pointed out.

Incidental adrenal nodules are identified in around 5% of patients who undergo CT. The prevalence of detecting incidentalomas increases with age, but most incidentally encountered adrenal pathology is benign and of little clinical relevance, they wrote. Adenomas are by far the most common adrenal pathology identified.

Among the technical aspects that deserve special attention are the following:

  • The region of interest (ROI): Changing the size of the ROI can alter the perceived attenuation of the nodule. The ROI should cover at least two-thirds of the circumference of the nodule, and exclude tiny areas of heterogeneity from the ROI (e.g., flecks of calcification) that are not representative of the adrenal pathology. Unenhanced attenuation of less than 10 Hounsfield units (HU) can be used to diagnose lipid-rich adrenal adenoma (sensitivity 71%, specificity of 98%).
  • Attenuation values on unenhanced CT: A homogenously dense lesion on unenhanced CT suggests a lack of microscopic lipid content. If attenuation on unenhanced CT is greater than 20 to 30 HU, evaluate the enhancement kinetics with CT.
  • Effect of kVp on attenuation values in a dual energy study: To use threshold of less than 10 HU to diagnose a lipid-rich adrenal adenoma, the kVp should be 120. Changing kVp can alter the attenuation values of soft tissues and adrenal glands.
  • Timing of post-contrast acquisitions: “Imaging needs to be performed at the correct times to allow sufficient time for enhancement and washout of contrast. Post-contrast images should be obtained at 60 to 75 seconds and 15 minutes,” the authors stated.
  • Assessment of washout on nondedicated studies: Relative washout can be calculated on nondedicated studies if more than one acquisition is made within 15 minutes post-intravenous contrast.
  • Suspicious attenuation: Attenuation of more than 43 HU on noncontrast CT is suspicious for malignancy, regardless of washout characteristics. PET/CT is of more use than CT and MRI in such cases, and adrenal hemorrhage also is a consideration at this attenuation.
  • Evaluation of small nodules: Minor nodularity of less than 1 cm in diameter does not require further radiological investigation. Also, CT evaluation of small adrenal nodules is limited by partial volume artifacts. MRI evaluation of small adrenal nodules is limited by the India ink artifact, or black boundary artifact, on an out-of-phase sequence. This artifact may give the impression of signal loss and lead to an incorrect diagnosis of a lipid-rich adenoma.
  • Evaluation of large adrenal masses: Malignancy risk increases with size (over 4 cm, 70%; over 6 cm, 85%) when excluding myelolipoma. In the absence of known malignancy, an adrenal lesion of less than 4 cm with indeterminate imaging features is likely to be benign.
  • Enhancement characteristics of metastases: Enhancement/washout characteristics of adrenal metastases are variable, and they can be confused with pheochromocytoma.
  • Adrenal calcification: Calcification is seen in benign adrenal pathology, but also can be seen in cases of malignancy, including adrenocortical carcinoma. “Look for ancillary features of malignancy including size, heterogeneity and invasion,” the authors recommended. “Evaluation of a predominantly calcified adrenal lesion will be limited with chemical shift MRI.”
  • Heterogeneous signal loss: Heterogeneous signal loss is not typical for a small lipid-rich adenoma and raises the possibility of malignant pathology. It also can be seen in larger adenomas because of calcification/cystic change/myelolipomatous metaplasia.

In their RSNA 2018 exhibit, Nandra and colleagues also identified the following list of mimics that can crop up:

  • Mimics arising from gastrointestinal tract: Gastric pathology can extend into the left suprarenal space and mimic adrenal pathology. The most common mimics include gastrointestinal stromal tumors and gastric diverticula. Pathology elsewhere in the gastrointestinal tract can mimic adrenal pathology (e.g., a fluid-filled colon).
  • Mimics arising from solid viscera: Pathology from the spleen, pancreas, liver, and kidneys can extend into the suprarenal space and mimic adrenal pathology. This includes splenic lobulation, splenunculi, upper pole renal pathology, pancreatic tail pathology, and exophytic hepatic lesions.
  • Mimics arising from vessels: Dilated, tortuous, or aneurysmal vessels may extend into the suprarenal space and mimic adrenal pathology. The most common mimics include splenic varices and splenic artery pseudoaneurysms.
  • Mimics arising from retroperitoneal tissues: Various retroperitoneal lesions can extend into the suprarenal space and mimic adrenal pathology, and normal anatomy in the retroperitoneum also can mimic adrenal pathology (e.g., a thickened diaphragmatic crus).

From https://www.auntminnieeurope.com/index.aspx?sec=ser&sub=def&pag=dis&ItemID=616803

Vision Loss The First Sign Of Adrenal Tumour In 42-Year-Old Patient

A 42-year-old woman who presented to hospital with acute vision loss in her right eye was diagnosed with a benign tumour in her adrenal gland.

Writing in BMJ Case Reports, clinicians described how the patient presented with a visual acuity of 6/36 in her right eye and 6/6 in her left eye.

Investigations revealed an exudative retinal detachment in her right eye as well as a pigment epithelial detachment.

The patient had multifocal central serous retinopathy in both eyes.

The woman, who had hypertension and diabetes, was diagnosed with Cushing syndrome and a right adrenal adenoma was also discovered.

During a treatment period that spanned several years, the patient received an adrenalectomy followed by a maintenance dose of steroids.

The patient subsequently developed central serous retinopathy again which the clinicians believe might be related to steroid use.

The authors advised “careful deliberation” in prescribing a maintenance dose of steroids following removal of the adrenal glands because of the potential link to retinopathy.

From https://www.aop.org.uk/ot/science-and-vision/research/2018/12/17/vision-loss-the-first-sign-of-adrenal-tumour-in-42-year-old-patient

Mutations in Two Genes, USP48 and BRAF, Linked to Cushing’s Disease

Mutations in USP48 and BRAF genes contribute to the overproduction of adrenocorticotropin (ACTH) hormone by the pituitary gland and consequent development of Cushing’s disease, a study shows, linking these genes to the disease for a first time.

The study, “Identification of recurrent USP48 and BRAF mutations in Cushing’s disease,” published in the journal Nature Communications, also identified a possible treatment for patients with BRAF-related mutations.

Cushing’s disease is a condition characterized by excessive cortisol levels that, if left untreated, can lead to serious cardiovascular problems, infections, and mood disorders. It usually arises from benign pituitary tumors that produce too much of ACTH hormone, which in turn stimulates the adrenal glands to secrete cortisol.

It is still not clear why some people develop these tumors, but studies have pointed to mutations in the USP8 gene as a possible cause. They are present in 35%–62% of all tumor cases, and influence treatment response and long-term outcomes.

But major disease drivers in people whose tumors have no evidence of  USP8 mutations are unknown. Recognizing this gap, researchers in China examined tumor tissue samples from 22 patients with pituitary ademonas but a normal USP8 gene.

Their analysis revealed four genes that were recurrently mutated, including two — BRAF and USP48 — never before reported in this disease setting. Then, looking at 91 samples from patients, researchers found BRAF mutations in 17% of cases and USP48 mutations in 23% of patients.

These mutations were also found in patients with USP8-mutant pituitary tumors, but at a much lower rate — 5.1% for BRAF and 1.2% for USP48 mutations.

However, mutations in these two genes were not seen in patients with pituitary tumors producing other hormones, suggesting they are “unique genetic signatures of [ACTH-producing] adenomas,” the researchers wrote.

The team also found that BRAF and USP48 mutations activate signaling pathways that lead to the production of proopiomelanocortin (POMC), which is the precursor of ACTH.

“ACTH overproduction is a hallmark of Cushing’s disease and appears to be frequently induced by mutations in genes that tightly regulate POMC gene transcription in the pathogenesis of this disease,” investigators wrote.

Patients with BRAF and USP48 mutations had significantly higher levels of midnight plasma ACTH and midnight serum cortisol, compared to patients without these mutations. Tumor size, however, was similar among the two groups.

Interestingly, the team found that the BRAF inhibitor Zelboraf (vemurafenib) effectively reduced ACTH production in cells from ACTH-producing pituitary tumors. Zelboraf, marketed by Genentech, is approved in the U.S. and Europe to treat cancers with BRAF mutations, and findings suggest it may be a good therapeutic candidate for some people with Cushing’s disease.

“The mutational status of BRAFUSP8, and USP48 in corticotroph adenomas may be used in the future to characterize the molecular subtypes and guide targeted molecular therapy,” the researchers suggested.

From https://cushingsdiseasenews.com/2018/11/20/mutations-in-usp48-braf-genes-contribute-for-cushings-disease-study-finds/

Most Subclinical Cushing’s Patients Don’t Require Glucocorticoids After Adrenalectomy

Patients with subclinical hypercortisolism, i.e., without symptoms of cortisol overproduction, and adrenal incidentalomas recover their hypothalamic-pituitary-adrenal (HPA) axis function after surgery faster than those with Cushing’s syndrome (CS), according to a study.

Moreover, the researchers found that an HPA function analysis conducted immediately after the surgical removal of adrenal incidentalomas — adrenal tumors discovered by chance in imaging tests — could identify patients in need of glucocorticoid replacement before discharge.

Using this approach, they found that most subclinical patients did not require treatment with hydrocortisone, a glucocorticoid taken to compensate for low levels of cortisol in the body, after surgery.

The study, “Alterations in hypothalamic-pituitary-adrenal function immediately after resection of adrenal adenomas in patients with Cushing’s syndrome and others with incidentalomas and subclinical hypercortisolism,” was published in Endocrine.

The HPA axis is the body’s central stress response system. The hypothalamus releases corticotropin-releasing hormone (CRH) that acts on the pituitary gland to release adrenocorticotropic hormone (ACTH), leading the adrenal gland to produce cortisol.

As the body’s defense mechanism to avoid excessive cortisol secretion, high cortisol levels alert the hypothalamus to stop producing CRH and the pituitary gland to stop making ACTH.

Therefore, in diseases associated with chronically elevated cortisol levels, such as Cushing’s syndrome and adrenal incidentalomas, there’s suppression of the HPA axis.

After an adrenalectomy, which is the surgical removal of one or both adrenal glands, patients often have low cortisol levels (hypocortisolism) and require glucocorticoid replacement therapy.

“Most studies addressing the peri-operative management of patients with adrenal hypercortisolism have reported that irrespective of how mild the hypercortisolism was, such patients were given glucocorticoids before, during and after adrenalectomy,” the researchers wrote.

Evidence also shows that, after surgery, glucocorticoid therapy is administered for months before attempting to test for recovery of HPA function.

For the past 30 years, researchers at the University Hospitals Cleveland Medical Center have withheld glucocorticoid therapy in the postoperative management of patients with ACTH-secreting pituitary adenomas until there’s proof of hypocortisolism.

“The approach offered us the opportunity to examine peri-operative hormonal alterations and demonstrate their importance in predicting need for replacement therapy, as well as future recurrences,” they said.

In this prospective observational study, the investigators extended their approach to patients with subclinical hypercortisolism.

“The primary goal of the study was to examine rapid alteration in HPA function in patients with presumably suppressed axis and appreciate the modulating impact of surgical stress in that setting,” they wrote. Collected data was used to decide whether to start glucocorticoid therapy.

The analysis included 14 patients with Cushing’s syndrome and 19 individuals with subclinical hypercortisolism and an adrenal incidentaloma. All participants had undergone surgical removal of a cortisol-secreting adrenal tumor.

“None of the patients received exogenous glucocorticoids during the year preceding their evaluation nor were they taking medications or had other illnesses that could influence HPA function or serum cortisol measurements,” the researchers noted.

Glucocorticoid therapy was not administered before or during surgery.

To evaluate HPA function, the clinical team took blood samples before and at one, two, four, six, and eight hours after the adrenalectomy to determine levels of plasma ACTH, serum cortisol, and dehydroepiandrosterone sulfate (DHEA-S) — a hormone produced by the adrenal glands.

Pre-surgery assessment of both groups showed that patients with an incidentaloma plus subclinical hypercortisolism had larger adrenal masses, higher ACTH, and DHEA-S levels, but less serum cortisol after adrenal function suppression testing with dexamethasone.

Dexamethasone is a man-made version of cortisol that, in a normal setting, makes the body produce less cortisol. But in patients with a suppressed HPA axis, cortisol levels remain high.

After the adrenalectomy, the ACTH concentrations in both groups of patients increased. This was found to be negatively correlated with pre-operative dexamethasone-suppressed cortisol levels.

Investigators reported that “serum DHEA-S levels in patients with Cushing’s syndrome declined further after adrenalectomy and were undetectable by the 8th postoperative hour,” while incidentaloma patients’ DHEA-S concentrations remained unchanged for the eight-hour postoperative period.

Eight hours after surgery, all Cushing’s syndrome patients had serum cortisol levels of less than 2 ug/dL, indicating suppressed HPA function. As a result, all of these patients required glucocorticoid therapy for several months to make up for HPA axis suppression.

“The decline in serum cortisol levels was slower and less steep [in the incidentaloma group] when compared to that observed in patients with Cushing’s syndrome. At the 6th–8th postoperative hours only 5/19 patients [26%] with subclinical hypercortisolism had serum cortisol levels at ≤3ug/dL and these 5 were started on hydrocortisone therapy,” the researchers wrote.

Replacement therapy in the subclinical hypercortisolism group was continued for up to four weeks.

Results suggest that patients with an incidentaloma plus subclinical hypercortisolism did not have an entirely suppressed HPA axis, as they were able to recover its function much faster than the CS group after surgical stress.

From https://cushingsdiseasenews.com/2018/10/11/most-subclinical-cushings-patients-dont-need-glucocorticoids-post-surgery-study/?utm_source=Cushing%27s+Disease+News&utm_campaign=a881a1593b-RSS_WEEKLY_EMAIL_CAMPAIGN&utm_medium=email&utm_term=0_ad0d802c5b-a881a1593b-72451321

Finding Ways to Deal with Post-surgery Anxieties

Post-traumatic stress disorder (PTSD) following Cushing’s disease is a real issue many of us face. However, we don’t have to let it control our lives — there are ways to cope.

Cushing’s changes us both mentally and physically. We become forgetful. We lose strength. We become someone we don’t recognize in the mirror. We lose hair on our heads and gain it everywhere else. We’re always in pain, and we’re always sick, with no end in sight (or at least it feels that way).

Some days will be trying and seem as if nothing seems to work, no matter what you do. I promise that you’re not alone, and you will make it through those days.

Following are a list of ways to deal with post-surgery scares:

  • Therapy/counseling: If you can afford it, talk with a professional about your health worries and how your anxiety affects you. It takes the burden off your caregivers who don’t like to see you suffer because they care so much.
  • Journaling: Journaling is a therapeutic and inexpensive way to let out your worries. Documenting your anxieties can help you keep track of how your thought processes are changing. Writing out your stresses is cathartic. Give it a try — if you haven’t already.
  • Yoga or any light exercise: If you’re in the early stages of recovery, you shouldn’t go straight back to the gym — working out is a stressor on the body. Light yoga, such as restorative yoga, in which you practice stretching, deep breathing, and relaxation, will help your mind and body to recover. Light walks are amazing for the brain and body post-surgery.
  • Delve into things you enjoy: Read, cook, go for walks, sit outside, etc. Do whatever feeds your soul and keeps your mind free from negative thoughts. Feeding your soul is one sure way to keep your mind and body happy and healthy.
  • Other ideas from the CushieWiki
  • Please share your ideas in the comments on this post or on the message boards

Adapted from https://cushingsdiseasenews.com/2018/10/19/cushings-post-surgery-anxieties-ptsd-post-traumatic-stress-disorder-journaling-yoga-therapy/

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