Dynamic pituitary MRI has high sensitivity and specificity for the diagnosis of mild Cushing's syndrome and should be part of the initial workup.

AIM: The diagnosis of mild or episodic Cushing's syndrome is difficult. The standard tests include 24-hour urinary free cortisol (UFC), night-time blood, or salivary cortisol measurements, and dexamethasone suppression tests. Imaging studies of the pituitary have not been recommended as part of the initial workup (only to help distinguish pituitary Cushing's disease from the ectopic ACTH syndrome) because of poor sensitivity and specificity. With the development of dynamic pituitary MRI which uses multiple coronal dynamic sequences following gadolinium intravenous contrast, we hypothesized that the sensitivity and specificity would be increased and MRI would provide useful information for the initial diagnosis of Cushing's syndrome. METHODS: This was a retrospective chart review examining charts from 87 consecutive patients who were evaluated for Cushing's syndrome in a tertiary Endocrinology clinic over a one-year period. Most patients had mild and/or episodic hypercortisolism. Of these patients, 24 eventually were diagnosed with pituitary Cushing's syndrome by biochemical testing (24-h UFC and urinary 17-hydroxycorticosteroids, 11 PM salivary cortisol measurements, evening plasma cortisol), and 22 had the diagnosis of Cushing's syndrome excluded. Dynamic pituitary MRI (1.5 Tesla) was performed on all patients. The reader of the MRI was blind to the diagnosis. RESULTS: Twenty-three of 24 patients had a MRI consistent with a pituitary lesion (21 with a microadenoma, two with pituitary asymmetry). In contrast, only 3 of 20 patients (2 patient did not have MRIs) in the Cushing's excluded group had a pituitary lesion on dynamic MRI. Dynamic pituitary MRI had the highest sensitivity and negative predictive value of any testing modalities and its specificity and positive predictive value were similar to that of other tests. CONCLUSION: We conclude that almost all patients in this series with Cushing's syndrome have a lesion on dynamic pituitary MRI, a rate much higher than the 50-60% rate reported for non-dynamic MRIs. The false positive rate of 16% in our group of Cushing's excluded patients is similar to the literature value of 10% seen in normal volunteers and is acceptable since MRI is not used solely as a determinant for the diagnosis. While a negative MRI will miss those patients with adrenal or ectopic Cushing's syndrome, those patients can usually be diagnosed by other testing. Thus this preliminary study implies that dynamic pituitary MRI adds valuable information to assist in the diagnosis of Cushing's syndrome and should be ordered as part of the initial workup.

A series of 112 fully endoscopic resections of vestibular schwannomas.

We report a consecutive series of 112 patients with unilateral vestibular schwannoma (VS) having undergone fully endoscopic resection of their tumors in the period from October, 2001 to January, 2005. Patients' outcomes were evaluated especially with regards to cochlear nerve (hearing) preservation, facial nerve preservation, postoperative complications and completeness of the resection. The patient population consisted of 112 consecutive cases with unilateral, "de novo" VS(s); patients with neurofibromatosis type 2 (NFT2) or with a recurrent tumor were excluded from this study. Tumors ranged in size from 0.6-5.7 cm, most tumors were less than 3 cm in diameter (mean: 2.6 cm). This shift towards smaller and also less symptomatic tumors may be due to an increase in the awareness of patients and earlier detection of their tumors (MRI era). Tumors were removed via 1.5-cm "keyhole" retrosigmoid craniotomies. Utilizing the fully endoscopic technique, 106/112 (95%) tumors were completely removed; subtotal removal was performed in 6/112 (5%) patients in an attempt to preserve their hearing. Anatomic preservation of the facial nerve was achieved in all of the patients and of the cochlear nerve in 83/101 (82%) hearing ears. Functionally, measurable hearing (serviceable/some) was preserved in 59/101 (58%) cases who had either "serviceable" or "some" hearing preoperatively, 2 patients who had "some" hearing preoperatively had an improvement that was more than 30 db in their hearing postoperatively. There were no major neurological complications such as quadriparesis, hemiparesis, bacterial or aseptic meningitis, lower cranial nerve deficits, or deaths. From our experience, we conclude that the endoscope is ideally suited for a minimally invasive approach for the resection of vestibular schwannomas.

Endoscopic vascular decompression versus microvascular decompression of the trigeminal nerve.

Microvascular decompression (MVD) is a highly accepted and effective method for treatment of patients with trigeminal neuralgia in whom compression of the nerve by a vascular structure is implicated in the pathogenesis of the disease. However, recent reports have highlighted the advantages of the endoscope in visualizing structures within the cerebellopontine angle. Additional research, using the endoscope to supplement the microscopic procedure, has demonstrated improved localization of neurovascular conflicts. In this report we present the results of our series utilizing a fully endoscopic vascular decompression (EVD) technique, and compare these results to those published for microvascular decompression. From September 1999 until October 2004, 255 patients underwent endoscopic vascular decompression of the trigeminal nerve. These patients' records were retrospectively reviewed, and additional data from follow-up visits were collected and analyzed to ascertain success rates and review the incidence of complications. From a total of 255 patients who underwent EVD of the trigeminal nerve we noted an initial, complete, postoperative success rate in 95 % of patients. Initial, being defined as within the first 3 months postoperative, and "complete" being judged if the patient reported 98 % relief of pain postoperatively without the need for medication (Barker's classification). Additionally, we documented a 93 % complete success rate for 118 patients who completed at least a three-year follow-up period. Complication rates were compared to those reported for MVD. There were no serious complications or mortality in this series. We conclude that EVD is a safe and effective method to remove neurovascular conflicts related to the trigeminal nerve. The results of this series demonstrate an improved rate of trigeminal neuralgia relief with EVD when compared to MVD, a lower incidence of complications and a better outcome.

Fully endoscopic endonasal vs. transseptal transsphenoidal pituitary surgery.

A long-term retrospective study of 300 patients who underwent fully endoscopic endonasal pituitary adenoma resection between November 1998 and October 2004. The patients' records as well as the data obtained from postoperative follow-up visits was used to determine outcomes. Additionally, the data were then compared to mean values calculated from several transseptal-transsphenoidal reports. From a total of 300 pituitary adenomas, 139 (46 %) were hormonally active, while 161 (54 %) were non-functioning. Mean follow-up period was 38.2 months. The average length of hospital stay (LOS) was 1.4 days. All patients had postoperative magnetic resonance imaging (MRI) studies to assess residual or recurrent disease; all patients with hormonally active tumors had additional postoperative hormonal studies. Remission, being defined as no hormonal or radiological evidence of recurrence within the time-frame of the follow-up, was demonstrated in 127/134 (95 %) of enclosed and 144/166 (87 %) of invasive adenomas. A comparison of fully endoscopic endonasal vs. transseptal-transsphenoidal remission results revealed an improved outcome using the fully endoscopic endonasal technique: ACTH (86 % vs. 81 %), PRL (89 % vs. 66 %) and GH (85 % vs. 77 %). The remission rate for non-functioning adenomas was 149/161 (93 %). Additionally, we noted a marked reduction in complications related to the endoscopic procedure. Our results conclude that the fully endoscopic endonasal technique is a safe and effective method for removal of pituitary adenomas providing more complete tumor removal and reducing complications.