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

Intraoperative MRI improves complete resection of pituitary macroadenoma

A 63-year-old man was referred to the Massachusetts General Hospital Neuroendocrine & Pituitary Tumor Clinical Center for management of a pituitary macroadenoma. He experienced increasingly severe retro-orbital headaches in the past year. He reported no double vision, fatigue, orthostatic dizziness, change in beard growth or reduction in libido. An outside head CT scan showed an enlarged pituitary gland.

Imaging and laboratory tests

A pituitary MRI with magnified pituitary slices and gadolinium contrast was ordered. A well-circumscribed “snowman-shaped” sellar mass was identified, measuring 2.6 cm x 2 cm x 1.8 cm (anteroposterior x transverse x craniocaudal) with suprasellar extension (Figure 1). The lesion was heterogeneous on T1-weighted scans after enhancement with IV gadolinium contrast. An area of hypointensity in the superior margin was consistent with a small area of cystic or hemorrhagic degeneration.

Although the mass did not extend laterally into the cavernous sinus, the sellar mass extended upward into the suprasellar cistern through a hole in the dural, the diaphragma sellae, to compress the optic chiasm. The restriction of adenoma growth by the diaphragma sellae results in the snowman shape of the macroadenoma. The optic chiasm and infundibulum (pituitary stalk) could not be identified on coronal or sagittal images (Figure 1). Visual field on confrontation suggested lateral field deficits (bilateral lateral hemianopsia) that were confirmed on formal Goldmann kinetic perimetry visual fields.

Figure 1. Preoperative MRI scan. A large “snowman-shaped” pituitary adenoma (green arrow) has heterogeneous enhancement after gadolinium contrast administration. A small hypodense area in the adenoma likely represented hemorrhage/cystic degeneration (yellow arrow). The tumor does not surround the carotid siphon, an S-shaped portion of the internal carotid artery (red arrows) within the cavernous sinus located laterally from the sella turcica where the pituitary gland resides. (A) Coronal image. (B) Sagittal image. Abbreviation: SS = spenoid sinus.

Source: Stephanie L. Lee, MD, PhD, ECNU. Reprinted with permission.

Initial hormonal evaluation was normal and included morning adrenocorticotropic hormone 18 pg/mL, cortisol 13.64 µg/dL, thyroid-stimulating hormone 2.14 uIU/mL, free thyroxine 1.2 ng/dL and prolactin 12.6 ng/mL. The patient’s morning testosterone level was normal at 324 ng/dL, with follicle-stimulating hormone 2.4 mIU/mL and luteinizing hormone 1.6 mIU/mL. His insulin-like growth factor I level was normal at 124 ng/mL.

Tumor resection

The patient was treated preoperatively with stress-dose hydrocortisone 50 mg. He then underwent transsphenoidal pituitary tumor resection. After the surgeon believed there was an adequate excision of the tumor, the extent of tumor resection was confirmed by an intraoperative MRI (Figure 2 on page 8).

Figure 2. Intraoperative MRI scan. The large macroadenoma is not seen after transsphenoidal surgery. The optic chiasm (yellow arrow) can be seen after removal of the tumor. (A) Coronal image. (B) Sagittal image. Abbreviation: SS = spenoid sinus.

The operation was concluded after the imaging confirmed the complete resection of the pituitary adenoma. The patient’s postoperative course was uneventful. Imaging 4 weeks after the resection confirmed complete resection of the suprasellar mass with residual enhancement of the resection bed and sphenoid sinuses (Figure 3 on page 8). The postoperative MRI revealed a normal optical chiasm and a downward tending of the infundibulum to the residual pituitary gland located inferiorly along the sella turcica (pituitary fossa) of the sphenoid bone. Pathology confirmed a pituitary adenoma. His anterior and posterior pituitary function were normal 6 weeks postoperatively, and his visual field deficit improved.

Intraoperative MRI

Imaging like that used in this case occurs in a specially designed operating room that allows MRI scans during surgery without moving the patient from the surgical table. The MRI is kept in a shielded enclosure during the procedure and then moved along a track into the operating room for imaging. Clinical indications for the use of intraoperative MRI in neurosurgery include resection of pituitary macroadenomas. In the past, these tumors underwent transsphenoidal resection, and the postoperative MRI was performed after 1 or more days after the procedure to check for complete removal. If residual tumor was found, the patients underwent watchful waiting, external radiation or repeat surgery.

The strategic advantage of an intraoperative MRI is that the imaging is performed during the operative procedure, and if there is any residual tumor, surgery can be resumed after the MRI is moved back into the shielded enclosure.

Figure 3. Four-week postoperative MRI scan. The large macroadenoma is not seen after the transsphenoidal survey. The optic chiasm and infundibulum (pituitary stalk) can be seen after resection of the tumor. The pituitary stalk is deviated to the left of the sella where the residual normal thyroid is locate along the sella turcica. The floor of the sella enhances with gadolinium infusion after surgery due to postoperative inflammation. (A) Coronal image. (B) Sagittal image. Abbreviation: SS = spenoid sinus.

It has been reported that the use of intraoperative MRI does not increase complication rates compared with conventional transsphenoidal surgery. Reports on the improvement of gross tumor resection using intraoperative MRI are variable, perhaps due to the expertise of the surgeon. Several reports suggest the use of intraoperative MRI allowed additional resection of noninvasive macroadenomas in 67% to 83% of the patients with a gross tumor resection. These results suggest that a substantial volume reduction and increased gross tumor resection of pituitary macroadenomas occurs with the use of intraoperative MRI compared with standard surgery. One study demonstrated that the gross tumor resection rates of invasive tumors was also improved with the use of intraoperative MRI compared with usual preoperative imaging and surgery (25% vs. 7%).

The use of intraoperative MRI, especially with transsphenoidal reoperations for invasive and noninvasive pituitary macroadenomas, leads to significantly higher “gross tumor resection” rates. This method prevents additional operations or treatment, such as radiation, because it reduces the number of patients with residual adenoma after surgery. This technology is usually found in specialized tertiary care hospitals but should be considered for reoperation for large pituitary macroadenomas or initial operation for large invasive pituitary macroadenomas.

Disclosures: Lee and Swearingen report no relevant financial disclosures.

From https://www.healio.com/endocrinology/neuroendocrinology/news/print/endocrine-today/%7B23183444-4d29-477b-844f-6eb995ac74f4%7D/intraoperative-mri-improves-complete-resection-of-pituitary-macroadenoma

Adrenal myelolipoma(s) as presenting manifestation of subclinical Cushing’s disease (eutopic ACTH-dependent Cushing’s syndrome)

  1. Partha Pratim Chakraborty1,
  2. Shinjan Patra1,
  3. Sugata Narayan Biswas1,
  4. Rana Bhattacharjee2

+Author Affiliations


  1. 1Department of MedicineMidnapore Medical College and HospitalMidnaporeWest Bengal, India

  2. 2Department of Endocrinology and MetabolismIPGME&R/SSKM HospitalKolkataWest Bengal, India
  1. Correspondence to Dr Partha Pratim Chakraborty, docparthapc@yahoo.co.in
  • Accepted 5 August 2017
  • Published 16 August 2017

Summary

Primary adrenal myelolipomas, relatively rare benign tumours of the adrenal cortex are typically unilateral, hormonally inactive and asymptomatic, hence often diagnosed as ‘adrenal incidentaloma’. Bilateral adrenal myelolipomas, in particular, may be associated with underlying endocrinopathies associated with elevated circulating adrenocorticotropic hormone (ACTH) concentration.

Subclinical cortisol hypersecretion, irrespective of its ACTH dependency, does not manifest typical clinical phenotype of hypercortisolemia, and thus termed subclinical Cushing’s syndrome.

In this article, hormonal evaluation in a middle-aged woman with diabetes, hypertension and incidentally discovered unilateral adrenal myelolipoma revealed underlying subclinical Cushing’s disease. Abdominal CT revealed another tiny focus in the contralateral adrenal gland, probably representing incipient myelolipoma.

From (you may buy the whole article at this link) http://casereports.bmj.com/content/2017/bcr-2017-221674.short?rss=1

Pituitary Issues: Irregular Periods

Q: I am 28 years old and I have not yet started my periods naturally. I have to take medicine for periods — Novelon. The doctors say that there is some problem with my hormones in the pituitary gland. Please advise me how to get normal and natural periods, because after taking the medicine I get my period, but without medicines I don’t.

A by Dr Sharmaine Mitchell: The problem you have with your menstrual period being irregular is most likely due to overproduction of the hormone prolactin by the pituitary gland in the brain. The pituitary gland can sometimes enlarge and cause an overproduction of prolactin and this can result in inappropriate milk production in the breasts (white nipple discharge), irregular menstruation or absent menstrual periods, headaches and blurred vision. The blurred vision occurs as a result of compression of the optic nerve which supplies the eyes, by the enlarged brain tumour in the pituitary gland.

You should get a magnetic resonance imaging (MRI) or CT scan of the brain and pituitary gland done. You should also test your prolactin levels to determine the extent of overproduction of the hormone.

Other investigations should include a thyroid function test (TSH), follicle stimulating hormone (FSH) and leutinizing hormone (LH), and baseline testosterone level tests.

Abnormalities in the production of thyroid hormones can also cause menstrual irregularities and this should be ruled out.

Polycystic ovarian disease can also cause irregular menstrual periods and checking the level of FSH, LH and testosterone will help to rule out this diagnosis. This condition is usually associated with excessive weight gain, abnormal male pattern distribution on the face, chest and abdomen and an increased risk for diabetes mellitus. A pelvic ultrasound to look at the structure of the ovaries and to rule out polycystic ovaries is essential.

If the pituitary gland is enlarged, then medication can be prescribed to shrink it. Bromocriptine or Norprolac are commonly used drugs which work well in reducing the prolactin levels and establishing regular menstrual cycles. The use of these drugs will also help to establish ovulation and improve your fertility.

In some cases it may become necessary to have surgery done if the tumour in the pituitary gland is large and does not respond to the usual medications prescribed to shrink the pituitary gland. The MRI of the brain and pituitary gland will give an idea as to the size of the gland and help to determine if there is a need for you to see the neurosurgeon.

In most cases medical management with drugs will work well and there is no need for surgical intervention. This is a problem that can recur, so it may be necessary to take treatment intermittently for a long period of time, especially if fertility is desired.

Consult your doctor who will advise you further. Best wishes.

Dr Sharmaine Mitchell is an obstetrician and gynaecologist. Send questions via e-mail to allwoman@jamaicaobserver.com; write to All Woman, 40-42 1/2 Beechwood Ave, Kingston 5; or fax to 968-2025. All responses are published. Dr Mitchell cannot provide personal responses.

DISCLAIMER:

The contents of this article are for informational purposes only and must not be relied upon as an alternative to medical advice or treatment from your own doctor.

From http://www.jamaicaobserver.com/magazines/allwoman/Still-no-normal-period-at-28_87596

Resolution of the physical features of Cushing’s syndrome in a patient with a cortisol secreting adrenocortical adenoma after unilateral adrenalectomy

A 37-year-old woman developed clinical manifestations of Cushing’s syndrome over a span of 2 years. Physical examination revealed features that best describe Cushing’s syndrome, such as wide purple striae (>1 cm) over the abdomen, facial plethora and easy bruisability.1  Other features observed were hypertension, moon facies, acne, a dorsocervical fat pad, central obesity and dyslipidaemia.

The diagnosis of hypercortisolism was confirmed using a 1 mg overnight dexamethasone suppression test (19.7 ng/dL, N: <1.8) and 24 h urine free cortisol (185.9 μg/24 h, N: 3.5–45). A suppressed adrenocorticotropic hormone (ACTH) level (4 pg/mL, N: 5–20) and a lack of hyperpigmentation suggested ACTH-independent Cushing’s syndrome. Further work up using CT with contrast of the adrenals showed a 2.4×2.3×2.4 cm right adrenal mass. The patient then underwent laparoscopic adrenalectomy of the right adrenal gland. Steroids was started postoperatively and tapered over time. Histopathology results were consistent with an adrenocortical adenoma (2.5 cm widest dimension). Six months after surgery, there was resolution of the physical features, weight loss and improvement in blood pressure.

Figure 1 is a serial photograph of the physical features seen in Cushing’s syndrome, such as moon facies, a dorsocervical fat pad and wide purple striae, taken preoperatively, and at 3 and 6 months after surgery. With treatment, physical and biochemical changes of Cushing’s syndrome both resolve through time.2 The time course of the resolution of these changes, however, is varied.2 ,3 We observed that the physical features were ameliorated at 3 months and resolved at 6 months.

Learning points

  • Physicians as well as patients should be aware that improvement of the features of Cushing’s syndrome after treatment does not occur immediately.

  • Dramatic resolution of the physical features of Cushing’s syndrome, however, can be observed as early as 6 months after surgery.

Figure 1

Physical features of Cushing’s syndrome (top to bottom: moon facies, a dorsocervical fat pad and wide purple striae (>1 cm) over the abdomen) documented before surgery, and at 3 and 6 months after surgery.

Footnotes

  • Twitter Follow John Paul Quisumbing at @jpquisumbingmd

  • Contributors JPMQ worked up the case and wrote the case report. MASS reviewed the case report and critically appraised it. JPMQ incorporated his suggestions.

  • Competing interests None declared.

  • Patient consent Obtained.

  • Provenance and peer review Not commissioned; externally peer reviewed.

References

From http://casereports.bmj.com/content/2016/bcr-2016-215693.short?rss=1

%d bloggers like this: