Pinakin R. Jethwa

Magnetic resonance thermometry-guided laser-induced thermal therapy for intracranial neoplasms: initial experience.

BACKGROUND: Laser-induced thermal therapy is a promising tool in the neurosurgeons armamentarium. This methodology has seen a resurgence in application as a result of advances in technology. OBJECTIVE: To report our initial experience with the procedure after treating 20 consecutive patients, the largest series to date. METHODS: Patients were selected for laser therapy if they had failed conventional therapies, were unable to tolerate an open cranial procedure, or the tumor was deemed otherwise inoperable. In this series, 980-nm diode laser catheters were placed stereotactically in the operating room. The patients were then transferred to the magnetic resonance imaging suite for thermal ablation. RESULTS: A total of 31 laser applicators were placed in 20 patients with intracranial neoplasms. The majority of patients (17 of 20) had prior treatment for their tumors. The overall accuracy of laser insertion was 83.9%, improving with increased experience. The average lesion volume treated was 7.0 ± 9.0 cm3. With the use of damage estimates from the software provided, the treatment continued until the entire tumor had been irreversibly ablated. The average length of hospitalization was 2.27 days, with the majority of patients going home on postoperative day 1. Complications occurred in 4 patients, typically in those who were in poor health preoperatively. CONCLUSION: Laser-induced thermal therapy is an intuitive procedure for treating difficult intracranial neoplasms. As with any other procedure, patient selection and lesion selection are important factors in determining outcome. ABBREVIATIONS: LITT, laser-induced thermal therapy Nd:YAG, neodymium-doped yttrium aluminum garnet PAD, precision aiming device

Volumetric trends associated with MRI-guided laser-induced thermal therapy (LITT) for intracranial tumors.

MR‐guided Laser Induced Thermal Therapy (LITT) is a procedure for intracranial tumors. Minimal data exists regarding post‐procedure lesion volume changes.

Treatment of a supratentorial primitive neuroectodermal tumor using magnetic resonance-guided laser-induced thermal therapy.

Supratentorial primitive neuroectodermal tumors (PNETs) are rare tumors that carry a poorer prognosis than those arising from the infratentorial compartment (such as medulloblastoma). The overall prognosis for these patients depends on several factors including the extent of resection, age at diagnosis, CSF dissemination, and site in the supratentorial space. The authors present the first case of a patient with a newly diagnosed supratentorial PNET in which cytoreduction was achieved with MR-guided laser-induced thermal therapy. A 10-year-old girl presented with left-sided facial weakness and a large right thalamic mass extending into the right midbrain. The diagnosis of supratentorial PNET was made after stereotactic biopsy. Therapeutic options for this lesion were limited because of the risks of postoperative neurological deficits with resection. The patient underwent MR-guided laser-induced thermal ablation of her tumor. Under real-time MR thermometry, thermal energy was delivered to the tumor at a core temperature of 90°C for a total of 960 seconds. The patient underwent follow-up MR imaging at regular intervals to evaluate the tumor response to the thermal ablation procedure. Initial postoperative scans showed an increase in the size of the lesion as well as the amount of the associated edema. Both the size of the lesion and the edema stabilized by 1 week and then decreased below preablation levels at the 3-month postsurgical follow-up. There was a slight increase in the size of the lesion and associated edema at the 6-month follow-up scan, presumably due to concomitant radiation she received as part of her postoperative care. The patient tolerated the procedure well and has had resolution of her symptoms since surgery. Further study is needed to assess the role of laser-induced thermal therapy for the treatment of intracranial tumors. As such, it is a promising tool in the neurosurgical armamentarium. Postoperative imaging has shown no evidence of definitive recurrence at the 6-month follow-up period, but longer-term follow-up is required to assess for late recurrence.

Three dimensional CT angiography versus digital subtraction angiography in the detection of intracranial aneurysms in subarachnoid hemorrhage

Introduction Ruptured intracranial aneurysms are responsible for over 90% of cases of spontaneous subarachnoid hemorrhage (SAH). Conventional digital subtraction angiography (DSA) remains the gold standard for diagnosing the source of SAH. A prospective study is presented wherein SAH patients underwent three dimensional CT angiography (CTA) prior to DSA in order to assess the specificity and sensitivity of this non-invasive modality to detect aneurysms. Methods 179 consecutive patients with spontaneous SAH presented over 36 months, as identified by screening CT and CTA. Patients with negative CTA findings underwent DSA within 24 h of presentation. All patients who were determined to have angiographically negative SAH underwent follow-up DSA 2 weeks later. Results Of the 179 patients screened by CTA, 13 (7%) were negative for aneurysms or other vascular lesions (arteriovenous malformation or dural fistula) on CTA and underwent DSA. No new lesions were identified on six vessel angiography, resulting in a 0% false negative rate (sensitivity 100%, predictive value 100%). MRI to rule out thrombosed aneurysms and repeat angiography at the 2 week follow-up were negative. Conclusions Sensitivity and specificity were higher than previously reported, suggesting that CTA may be used as an initial screening tool in lieu of DSA. Further studies are necessary to determine if CTA can supplant DSA in ruling out all forms of vascular disease in idiopathic SAH.

117 Digital Substraction Angiography in CT Angiography Negative Spontaneous Subarachnoid HemorrhageA Cost-Effectiveness Analysis

Recent studies have documented the high sensitivity of CT angiography (CTA) in detecting a ruptured aneurysm in the presence of acute subarachnoid hemorrhage (SAH). The practice of digital subtraction angiography (DSA) when CTA does not reveal an aneurysm has thus been called into question. We examined the efficacy of DSA in CTA negative SAH when balanced with the costs and risks associated with the procedure.

Cost-Effectiveness Analysis of Microscopic and Endoscopic Transsphenoidal Surgery Versus Medical Therapy in the Management of Microprolactinoma in the United States.

BACKGROUND Although prolactinomas are treated effectively with dopamine agonists, some have proposed curative surgical resection for select cases of microprolactinomas to avoid life-long medical therapy. We performed a cost-effectiveness analysis comparing transsphenoidal surgery (either microsurgical or endoscopic) and medical therapy (either bromocriptine or cabergoline) with decision analysis modeling. METHODS A 2-armed decision tree was created with TreeAge Pro Suite 2012 to compare upfront transsphenoidal surgery versus medical therapy. The economic perspective was that of the health care third-party payer. On the basis of a literature review, we assigned plausible distributions for costs and utilities to each potential outcome, taking into account medical and surgical costs and complications. Base-case analysis, sensitivity analysis, and Monte Carlo simulations were performed to determine the cost-effectiveness of each strategy at 5-year and 10-year time horizons. RESULTS In the base-case scenario, microscopic transsphenoidal surgery was the most cost-effective option at 5 years from the time of diagnosis; however, by the 10-year time horizon, endoscopic transsphenoidal surgery became the most cost-effective option. At both time horizons, medical therapy (both bromocriptine and cabergoline) were found to be more costly and less effective than transsphenoidal surgery (i.e., the medical arm was dominated by the surgical arm in this model). Two-way sensitivity analysis demonstrated that endoscopic resection would be the most cost-effective strategy if the cure rate from endoscopic surgery was greater than 90% and the complication rate was less than 1%. Monte Carlo simulation was performed for endoscopic surgery versus microscopic surgery at both time horizons. This analysis produced an incremental cost-effectiveness ratio of

Accuracy of Computed Tomographic Angiography Compared to Digital Subtraction Angiography in the Diagnosis of Intracranial Stenosis and its Impact on Clinical Decision-making

80,235 per quality-adjusted life years at 5 years and

Cost-effectiveness of digital subtraction angiography in the setting of computed tomographic angiography negative subarachnoid hemorrhage.

40,737 per quality-adjusted life years at 10 years, implying that with increasing time intervals, endoscopic transsphenoidal surgery is the more cost-effective treatment strategy. CONCLUSIONS On the basis of the results of our model, transsphenoidal surgical resection of microprolactinomas, either microsurgical or endoscopic, appears to be more cost-effective than life-long medical therapy in young patients with life expectancy greater than 10 years. We caution that surgical resection for microprolactinomas be performed only in select cases by experienced pituitary surgeons at high-volume centers with high biochemical cure rates and low complication rates.

Cost-effectiveness of computed tomographic angiography in screening for aneurysm in spontaneous subarachnoid hemorrhage.

BACKGROUND Few studies to date have examined the accuracy of computed tomographic angiography (CTA) compared to digital subtraction angiography (DSA) in diagnosing intracranial stenosis. The purpose of this study was to compare CTA to DSA in diagnosing intracranial stenosis and to explore the impact of the addition of DSA on the management of stroke patients. METHODS We retrospectively reviewed all ischemic stroke or patients with transient ischemic attack who underwent CTA and DSA within 30 days of each other at our institution between January 2008 and July 2011. For each study, 2 blinded observers rated the degree of stenosis of 11 intracranial vessels. Disagreements were adjudicated by a third blinded observer. Sensitivity, specificity, negative predictive value, and receiver operating characteristic curves were determined using DSA as the criterion standard. All patient charts were reviewed to determine if the addition of DSA to CTA impacted clinical management. RESULTS Six hundred twenty-seven arterial segments were reviewed. The sensitivity of CTA to diagnose stenosis >50% was 96.6% (95% confidence interval [CI] 88.1-99.6), specificity 99.4% (95% CI 98.1-99.9), and negative predictive value 99.6% (95% CI 98.4-99.9). The intraclass correlation between CTA and DSA measurements was 0.96 (95% CI 0.95-0.97). Five of 57 patients underwent intracranial stenting procedures during the study period. All 5 lesions were correctly characterized as having >70% stenosis on CTA. Of the remaining 52 patients, none had clinical management change based on DSA findings. CONCLUSIONS CTA has a high sensitivity and specificity compared to DSA to diagnose intracranial stenosis. The addition of DSA to CTA may not affect clinical management in most patients with suspected stenosis.

Strategies for asymptomatic carotid artery stenosis.

BACKGROUND Recent studies have documented the high sensitivity of computed tomography angiography (CTA) in detecting a ruptured aneurysm in the presence of acute subarachnoid hemorrhage (SAH). The practice of digital subtraction angiography (DSA) when CTA does not reveal an aneurysm has thus been called into question. OBJECTIVE We examined this dilemma from a cost-effectiveness perspective by using current decision analysis techniques. METHODS A decision tree was created with the use of TreeAge Pro Suite 2012; in 1 arm, a CTA-negative SAH was followed up with DSA; in the other arm, patients were observed without further imaging. Based on literature review, costs and utilities were assigned to each potential outcome. Base-case and sensitivity analyses were performed to determine the cost-effectiveness of each strategy. A Monte Carlo simulation was then conducted by sampling each variable over a plausible distribution to evaluate the robustness of the model. RESULTS With the use of a negative predictive value of 95.7% for CTA, observation was found to be the most cost-effective strategy (