Internal medicine

Radiology

Retrospective cohort study

Desmopressin

Dexamethasone

Nuclear medicine

Predictive value

Biology

Gastroenterology

Endocrinology

Magnetic resonance imaging

Paleontology

Context (archaeology)

Dexamethasone suppression test

Positive predicative value

Pituitary disorder

Hormone

Medicine

The Journal of Clinical Endocrinology & Metabolism

Context Inferior petrosal sinus sampling (IPSS) is used to diagnose Cushing’s disease (CD) when dexamethasone-suppression and CRH tests, and pituitary magnetic resonance imaging (MRI), are negative or give discordant results. However, IPSS is an invasive procedure and its availability is limited. Objective To test a noninvasive diagnostic strategy associated with 100% positive predictive value (PPV) for CD. Design Retrospective study. Setting Two university hospitals. Patients A total of 167 patients with CD and 27 patients with ectopic ACTH-syndrome investigated between 2001 and 2016. Main Outcome Measure(s) Performance of a strategy involving the CRH and desmopressin tests with pituitary MRI followed by thin-slice whole-body computed tomography (CT) scan in patients with inconclusive results. Results Using thresholds of a cortisol increase &amp;gt; 17% with an ACTH increase &amp;gt; 37% during the CRH test and a cortisol increase &amp;gt; 18% with an ACTH increase &amp;gt; 33% during the desmopressin test, the combination of both tests gave 73% sensitivity and 98% PPV of CD. The sensitivity and PPV for pituitary MRI were 71% and 99%, respectively. CT scan identified 67% EAS at presentation with no false-positives. The PPV for CD was 100% in patients with positive responses to both tests, with negative pituitary MRI and CT scan. The Negative Predictive Value was 100% in patients with negative responses to both tests, with negative pituitary MRI and positive CT scan. Using this strategy, IPPS could have been avoided in 47% of patients in whom it is currently recommended. Conclusions In conjunction with expert radiologic interpretation, the non-invasive algorithm studied significantly reduces the need for IPSS in the investigation of ACTH-dependent Cushing’s syndrome.

Non-invasive Diagnostic Strategy in ACTH-dependent Cushing’s Syndrome