Cushing's disease (CD) is the result of excess secretion of adrenocorticotropic hormone (ACTH) by a benign monoclonal pituitary adenoma. The excessive secretion of ACTH stimulates secretion of cortisol by the adrenal glands, resulting in supraphysiological levels of circulating cortisol. The pathophysiological levels of cortisol are associated with hypertension, diabetes, obesity, and early death. Successful resection of the CD-associated ACTH-secreting pituitary adenoma is the treatment of choice and results in immediate biochemical remission with preservation of pituitary function. Accurate and early identification of CD is critical for effective surgical management and optimal prognosis. The authors review the current pathophysiological principles, diagnostic methods, and management of CD.
Russell R. Lonser, Lynnette Nieman and Edward H. Oldfield
Prashant Chittiboina, S. Lalith Talagala, Hellmut Merkle, Joelle E. Sarlls, Blake K. Montgomery, Martin G. Piazza, Gretchen Scott, Abhik Ray-Chaudhury, Russell R. Lonser, Edward H. Oldfield, Alan P. Koretsky and John A. Butman
Pituitary MR imaging fails to detect over 50% of microadenomas in Cushing's disease and nearly 80% of cases of dural microinvasion. Surface coils can generate exceptionally high-resolution images of the immediately adjacent tissues. To improve imaging of the pituitary gland, a receive-only surface coil that can be placed within the sphenoid sinus (the endosphenoidal coil [ESC]) during transsphenoidal surgery (TSS) was developed and assessed.
Five cadaver heads were used for preclinical testing of the ESC. The ESC (a double-turn, 12-mm-diameter surface coil made from 1-mm-diameter copper wire) was developed to obtain images in a 1.5-T MR scanner. The ESC was placed (via a standard sublabial TSS approach) on the anterior sella face. Clinical MR scans were obtained using the 8-channel head coil and ESC as the receiver coils. Using the ESC, ultra–high-resolution, 3D, balanced fast field echo (BFFE) and T1-weighted imaging were performed at resolutions of 0.25 × 0.25 × 0.50 mm3 and 0.15 × 0.15 × 0.30 mm3, respectively.
Region-of-interest analysis indicated a 10-fold increase in the signal-to-noise ratio (SNR) of the pituitary when using the ESC compared with the 8-channel head coil. ESC-related improvements (p < 0.01) in the SNR were inversely proportional to the distance from the ESC tip to the anterior pituitary gland surface. High-resolution BFFE MR imaging obtained using ESC revealed a number of anatomical features critical to pituitary surgery that were not visible on 8-channel MR imaging, including the pituitary capsule, the intercavernous sinus, and microcalcifications in the pars intermedia. These ESC imaging findings were confirmed by the pathological correlation with whole-mount pituitary sections.
ESC can significantly improve SNR in the sellar region intraoperatively using current 1.5-T MR imaging platforms. Improvement in SNR can provide images of the sella and surrounding structures with unprecedented resolution. Clinical use of this ESC may allow for MR imaging detection of previously occult pituitary adenomas and identify microscopic invasion of the dura or cavernous sinus.
Edward H. Oldfield, John A. Jane Jr., Michael O. Thorner, Carrie L. Pledger, Jason P. Sheehan and Mary Lee Vance
The relationship between growth hormone (GH) and insulin-like growth factor–1 (IGF-1) in patients with acromegaly as serial levels drop over time after treatment has not been examined previously. Knowledge of this relationship is important to correlate pretreatment levels that best predict response to treatment. To examine the correlation between GH and IGF-1 and IGF-1 z-scores over a wide range of GH levels, the authors examined serial GH and IGF-1 levels at intervals before and after surgery and radiosurgery for acromegaly.
This retrospective analysis correlates 414 pairs of GH and IGF-1 values in 93 patients with acromegaly.
Absolute IGF-1 levels increase linearly with GH levels only up to a GH of 4 ng/ml, and with IGF-1 z-scores only to a GH level of 1 ng/ml. Between GH levels of 1 and 10 ng/ml, increases in IGF-1 z-scores relative to changes in GH diminish and then plateau at GH concentrations of about 10 ng/ml. From patient to patient there is a wide range of threshold GH levels beyond which IGF-1 increases are no longer linear, GH levels at which the IGF-1 response plateaus, IGF-1 levels at similar GH values after the IGF-1 response plateaus, and of IGF-1 levels at similar GH levels.
In acromegaly, although IGF-1 levels represent a combination of the integrated effects of GH secretion and GH action, the tumor produces GH, not IGF-1. Nonlinearity between GH and IGF-1 occurs at GH levels far below those previously recognized. To monitor tumor activity and tumor viability requires measurement of GH levels.
Houssein A. Darwish and Edward H. Oldfield
This report describes the circumstances of a patient with a cauda equina syndrome due to the development of a lumbar subdural CSF collection with ventral displacement of the cauda equina shortly following posterior fossa decompression for Chiari malformation Type I (CM-I). This unusual, but clinically significant, complication was successfully treated with percutaneous drainage of the extraarachnoid CSF collection. Although there are a few cases of intracranial subdural hygroma developing after surgery for CM-I, often attributed to a pinhole opening in the arachnoid, as far as the authors can determine, a spinal subdural hygroma associated with surgery for CM-I has not been recognized.
Davis G. Taylor, Panagiotis Mastorakos, John A. Jane Jr. and Edward H. Oldfield
A subset of patients with Chiari I malformation demonstrate patent subarachnoid spaces around the cerebellum, indicating that reduced posterior fossa volume alone does not account for tonsillar descent. The authors distinguish two subsets of Chiari I malformation patients based on the degree of “posterior fossa crowdedness” on MRI.
Two of the coauthors independently reviewed the preoperative MR images of 49 patients with Chiari I malformation and categorized the posterior fossa as “spacious” or “crowded.” Volumetric analysis of posterior fossa structures was then performed using open-source DICOM software. The preoperative clinical and imaging features of the two groups were compared.
The posterior fossae of 25 patients were classified as spacious and 20 as crowded by both readers; 4 were incongruent. The volumes of the posterior fossa compartment, posterior fossa tissue, and hindbrain (posterior fossa tissue including herniated tonsils) were statistically similar between the patients with spacious and crowed subtypes (p = 0.33, p = 0.17, p = 0.20, respectively). However, patients in the spacious and crowded subtypes demonstrated significant differences in the ratios of posterior fossa tissue to compartment volumes as well as hindbrain to compartment volumes (p = 0.001 and p = 0.0004, respectively). The average age at surgery was 29.2 ± 19.3 years (mean ± SD) and 21.9 ± 14.9 years for spacious and crowded subtypes, respectively (p = 0.08). Syringomyelia was more prevalent in the crowded subtype (50% vs 28%, p = 0.11).
The authors' study identifies two subtypes of Chiari I malformation, crowded and spacious, that can be distinguished by MRI appearance without volumetric analysis. Earlier age at surgery and presence of syringomyelia are more common in the crowded subtype. The presence of the spacious subtype suggests that crowdedness alone cannot explain the pathogenesis of Chiari I malformation in many patients, supporting the need for further investigation.
Andrew S. Little, Daniel F. Kelly and Garni Barkhoudarian
Carrie L. Pledger, Mohamed A. Elzoghby, Edward H. Oldfield, Spencer C. Payne and John A. Jane Jr.
Both endoscopic and microscopic transsphenoidal approaches are accepted techniques for the resection of pituitary adenomas. Although studies have explored patient outcomes for each technique individually, none have prospectively compared sinonasal and quality of life outcomes in a concurrent series of patients at the same institution, as has been done in the present study.
Patients with nonfunctioning adenomas undergoing transsphenoidal surgery were assessed for sinonasal function, quality of life, and pain using the Sino-Nasal Outcome Test-20 (SNOT-20), the short form of the Nasal Obstruction Symptom Evaluation (NOSE) instrument, the SF-36, and a headache scale. Eighty-two patients undergoing either endoscopic (47 patients) or microscopic (35 patients) surgery were surveyed preoperatively and at 24–48 hours, 2 weeks, 4 weeks, 8 weeks, and 1 year after surgery.
Patients who underwent endoscopic and microscopic transsphenoidal surgery experienced a similar recovery pattern, showing an initial increase in symptoms during the first 2 weeks, followed by a return to baseline by 4 weeks and improvement beyond baseline functioning by 8 weeks. Patients who underwent endoscopic surgery experienced better sinonasal outcomes at 24–48 hours (SNOT total p = 0.015, SNOT rhinologic subscale [ssRhino] p < 0.001), 2 weeks (NOSE p = 0.013), and 8 weeks (SNOT total p = 0.032 and SNOT ssRhino p = 0.035). By 1 year after surgery, no significant differences in sinonasal outcomes were observed between the 2 groups. Headache scales at 1 year improved in all dimensions except duration for both groups (total result 73%, p = 0.004; severity 46%, p < 0.001; frequency 53%, p < 0.001), with 80% of either microscopic or endoscopic patients experiencing improvement or resolution of headache symptoms. Endoscopic and microscopic patients experienced reduced vitality preoperatively compared with US population norms and remained low postoperatively. By 8 weeks after surgery, both groups experienced significant improvements in mental health (13%, p = 0.005) and vitality (15%, p = 0.037). By 1 year after surgery, patients improved significantly in mental health (14%, p = 0.03), role physical (14%, p = 0.036), social functioning (16%, p = 0.009), vitality (22%, p = 0.002), and SF-36 total (10%, p = 0.024) as compared with preoperative measures. There were no significant differences at any time point between the 2 groups for the total SF-36 or for any of the 8 subscales.
Patients who underwent either an endoscopic or a microscopic approach experienced the greatest nasal symptoms at 2 weeks postoperatively and exhibited similar time courses of recovery in nasal, headache, and quality of life assessments. Although patients who underwent endoscopic surgery experienced significantly fewer nasal symptoms during the first 8 weeks, by 1 year after surgery, there were no significant differences between the 2 groups.
Kristin Huntoon, Tianxia Wu, J. Bradley Elder, John A. Butman, Emily Y. Chew, W. Marston Linehan, Edward H. Oldfield and Russell R. Lonser
Peritumoral cysts are frequently associated with CNS hemangioblastomas and often underlie neurological morbidity and mortality. To determine their natural history and clinical impact, the authors prospectively analyzed hemangioblastoma-associated peritumoral cysts in patients with von Hippel-Lindau (VHL) disease.
Patients with VHL disease who had 2 or more years of follow-up and who were enrolled in a prospective study at the National Institutes of Health were included. Serial prospectively acquired laboratory, genetic, imaging, and clinical data were analyzed.
One hundred thirty-two patients (of 225 in the VHL study with at least 2 years of follow-up) had peritumoral cysts that were followed for more than 2 years (total of 292 CNS peritumoral cysts). The mean age at study entrance was 37.4 ± 13.1 years ([mean ± SD], median 37.9, range 12.3–65.1 years). The mean follow-up was 7.0 ± 1.7 years (median 7.3, range 2.1–9.0 years). Over the study period, 121 of the 292 peritumoral cysts (41.4%) became symptomatic. Development of new cysts was associated with a larger number cysts at study enrollment (p = 0.002) and younger age (p < 0.0001). Cyst growth rate was associated with anatomical location (cerebellum cysts grew faster than spine and brainstem cysts; p = 0.0002 and p = 0.0008), younger age (< 35 years of age; p = 0.0006), and development of new neurological symptoms (p < 0.0001). Cyst size at symptom production depended on anatomical location (p < 0.0001; largest to smallest were found, successively, in the cerebellum, spinal cord, and brainstem). The most common location for peritumoral cysts was the cerebellum (184 cysts [63%]; p < 0.0001).
Peritumoral cysts frequently underlie symptom formation that requires surgical intervention in patients with VHL disease. Development of new cysts was associated with a larger number of cysts at study enrollment and younger age. Total peritumoral cyst burden was associated with germline partial deletion of the VHL gene.
Kristin Huntoon, Edward H. Oldfield and Russell R. Lonser
Arvid Lindau, MD, PhD, consolidated the disparate array of benign and malignant visceral and nervous system lesions into the neoplastic syndrome known as von Hippel-Lindau (VHL) disease. Based on this pioneering work, Dr. Lindau was awarded both a Rockefeller fellowship to work in Dr. Harvey Cushing's laboratory in Boston, Massachusetts, and the Lennmalm Prize. While working in Dr. Cushing's laboratory, Dr. Lindau continued his study of CNS hemangioblastomas. His work with Dr. Cushing led to their lifelong friendship and scientific collaboration. In this paper the authors describe Arvid Lindau's pioneering work in nervous system tumor pathology, his relationship to Dr. Cushing, and his role in advancing neurological surgery and research in Europe.