Feasibility of Endosphenoidal Coil Placement for Imaging of the Sella During Transsphenoidal Surgery
Feasibility of Endosphenoidal Coil Placement for Imaging of the Sella During Transsphenoidal Surgery
Background:

 Pituitary tumors can cause problems by secreting hormones in the body. They can also problems
 by growing large and pushing on organs near the pituitary gland. The best treatment for such
 tumors is to remove them by surgery. But that may be sometimes difficult. Some tumors maybe
 too small to see. Some other tumors maybe so large that portions maybe left behind during
 surgery. The endosphenoidal coil (ESC) is a new magnetic resonance imaging (MRI) device. It
 fits in a small space made during surgery near the pituitary. Researchers want to see if it
 helps transmit MRI signals during surgery to make better images of the pituitary gland and
 tumors.

 Objective:

 To test the safety of using a new coil device to improve MRI imaging of pituitary tumors
 during surgery.

 Eligibility:

 Adults 18-65 years old who are having pituitary tumor surgery at NIH

 Design:

 Participants will be screened with:

 -  Medical history

 -  Physical exam

 -  Review of prior brain scans

 -  Blood and pregnancy tests

 All participants will have MRI of pituitary gland. They will lie on a table that slides into
 a metal cylinder in a strong magnetic field. They will lie still and get earplugs for loud
 sounds. A dye will be inserted into an arm vein by needle.

 Participants will stay in the hospital for about 1 week. They will repeat screening tests.

 Participants will have standard pituitary surgery. They will get medicine to go to sleep. The
 surgeon will create a path to the pituitary gland from under the lip.

 During surgery, the ESC will be placed through the path to near the pituitary. Then an MRI
 will be done during surgery.

 Then the ESC will be removed and standard surgery will continue.

 Participants will get standard post-operative care under another protocol.
Tumors of the pituitary gland comprise up to 20% of all brain tumors. The central location
 and the small size of the pituitary gland make the management of tumors particularly
 challenging. Transsphenoidal surgery (TSS) to resect pituitary tumors is highly successful at
 achieving complete cure for functional pituitary adenomas. It is most successful when such
 adenomas can be localized by preoperative MRI of the pituitary. However, in some instances,
 small functional tumors cannot be visualized. In the case of Cushing s disease (CD), such
 non-visualization may be as high as 50%. The success of transsphenoidal surgery is
 substantially reduced in patients with negative MRI, as some of the adenomas that cause CD
 are so small that they are difficult to find during surgical exploration of the pituitary.
 Surgical success is also diminished when tumors invade the walls of the cavernous sinus. MRI
 of the pituitary lacks imaging resolution to detect such invasion and so the surgeon cannot
 perform a complete resection with surgery based on the preoperative MRI.

 Signal to noise ratio (SNR) is the primary constraint on achieving high quality high
 resolution MRI images. SNR can be improved by longer scan times or by increasing the field
 strength of the MRI magnet. SNR is proportional to the square of imaging time, however, long
 imaging times are not clinically feasible. SNR is linearly proportional to field strength,
 however, replacing MRI magnets is cost prohibitive.

 Another strong determinant of SNR is the proximity of the MRI receiver coil to the tissue
 being imaged. Placement of a coil in close proximity to the structure of interest
 dramatically increases SNR, often as much as 10-fold. Clinically this is routinely put into
 practice for superficial body parts, such as the temporomandibular joints, in which small
 coils are placed directly over the joints to achieve rapid high-resolution imaging. For deep
 structures, the use of superficial coils is of no benefit. This has led to the development of
 endocavitary coils, such as the endorectal coil used to image the prostate gland. Such coils
 are now in routine clinical use here at the NIH and elsewhere.

 During routine TSS, the surgical approach to the pituitary provides a route for placement of
 imaging tools, such as handheld ultrasound and Doppler probes in close proximity to the
 gland. Extending this model to MRI imaging, we realized that an endocavitary surface coil
 within the sphenoid sinus will allow for a marked improvement in SNR for imaging the sella.
 To this end, we have developed an endosphenoidal coil (ESC), demonstrated its MRI safety, and
 performed preliminary studies in cadaver heads to determine that the ESC can be placed
 through the transsphenoidal approach. Placement of ESC needs no modification in the surgical
 TSS approach to the pituitary gland. The goal of this protocol is to examine the safety and
 feasibility of ESC placement and imaging during TSS.

 Objective

 To evaluate the feasibility and safety of using ESC during TSS.

 Study Population

 The study population will be up to 20 adult subjects with pituitary tumors that require TSS.
 Enrollment will be completed once 10 subjects have received the study procedure. The
 requested accrual ceiling of 20 subjects accounts for screening failures and drop-outs who do
 not receive the study procedure.

 Design

 This is a feasibility study of 10 subjects requiring TSS for pituitary lesions. The subjects
 will undergo standard TSS resection of a pituitary adenoma in the intra-operative MR suite.
 Following standard surgical approach, the ESC will be placed into the sphenoid sinus, while
 the bone of the sellar floor is still intact. Routine clinical pituitary imaging with and
 without intravenous contrast will be performed for comparison with standard pituitary
 imaging. Additional higher resolution sequences will be performed as time allows. Following
 imaging, standard surgical resection will be performed. Surgeon will not view scans arising
 from the research procedure and therefore intraoperative clinical decisions making will not
 be influenced by the results of the research imaging.

 Outcome Measures

 Primary Outcome Measure

 The primary outcome of this study is the feasibility of using ESC as a clinical tool during
 transsphenoidal surgery. Feasibility will be assessed by the time added to a standard TSS
 procedure (measured from the time the TSS exposure is completed to the time to return to the
 operating position for completion of surgery).

 Safety Outcome Measure

 We will evaluate the safety of the ESC as a surgical adjunct tool. We will evaluate whether
 the use of ESC causes local trauma, bleeding, burns or other unanticipated safety issues
 during TSS.

 Exploratory Outcome Measures

 Clinical utility of these images will be evaluated by comparing SNR and contrast to noise
 ratio (CNR) measurements obtained with the ESC to preoperative standard of care images.

 1. Pituitary SNR with ESC MRI versus pre-operative standard of care images.

 2. Pituitary to tumor Contrast to Noise Ratio (CNR) with ESC MRI versus pre-operative
 standard of care images.
-  INCLUSION CRITIERIA:

 Adult subjects (more than 18 years of age) will be included in this study if they:

 1. Have a known or suspected tumor of the pituitary gland that requires surgical
 resection through a transsphenoidal approach. There is no size restriction. Invasion
 of surrounding anatomical structures by the pituitary tumor will not be ground for
 screen failure/withdrawal from study.

 2. Are enrolled in 03-N-0164, Evaluation and Treatment of Neurosurgical Disorders. If not
 enrolled, subjects will not be able to be included in the study as clinical and
 research procedures are done under the 03-N-0164 protocol.

 3. Are able to provide written consent

 4. NIH employees are included in the study

 EXCLUSION CRITIERIA:

 Subjects will be excluded from this study if they:

 1. Are unable to fit the intra-operative MRI table due to size or weight restrictions i.e
 morbid obesity. Patients will be anaesthetized and therefore claustrophobia will not
 be ground for screen failure/withdrawal from study.

 2. Have an absolute contraindication to MRI imaging or MRI contrast agent according to
 Rad&IS screening including devices or conditions.

 3. Have a variant anatomy which may, in the judgment of the operating neurosurgeon, add
 unacceptable risk to the placement of the endosphenoidal coil (e.g. small size of
 facial bones and nasal passages, unaerated sphenoid sinus etc.).

 4. Are pregnant or nursing.

 5. Patients older than 65 years of age. Cushing disease is rare in the older population.

 The Eligibility Checklist is included as an attachment. This checklist is used by the
 investigator at the time of screening for admission to the protocol.