The impact of cigarette smoking and nicotine on traumatic brain injury: a review.

INTRODUCTION: Traumatic Brain Injury (TBI) and tobacco smoking are both serious public health problems. Many people with TBI also smoke. Nicotine, a component of tobacco smoke, has been identified as a premorbid neuroprotectant in other neurological disorders. This study aims to provide better understanding of relationships between tobacco smoking and nicotine use and effect on outcome/recovery from TBI. METHODS: PubMed database, SCOPUS, and PTSDpub were searched for relevant English-language papers. RESULTS: Twenty-nine human clinical studies and nine animal studies were included. No nicotine-replacement product use in human TBI clinical studies were identified. While smoking tobacco prior to injury can be harmful primarily due to systemic effects that can compromise brain function, animal studies suggest that nicotine as a pharmacological agent may augment recovery of cognitive deficits caused by TBI. CONCLUSIONS: While tobacco smoking before or after TBI has been associated with potential harms, many clinical studies downplay correlations for most expected domains. On the other hand, nicotine could provide potential treatment for cognitive deficits following TBI by reversing impaired signaling pathways in the brain including those involving nAChRs, TH, and dopamine. Future studies regarding the impact of cigarette smoking and vaping on patients with TBI are needed .

Effects of platelet dysfunction and platelet transfusion on outcomes in traumatic brain injury patients.

OBJECTIVE: Platelet inhibition in traumatic brain injury (TBI) may be due to injury or antiplatelet medication use pre-injury. This study aims to identify factors associated with increased platelet arachidonic acid (AA) and adenosine diphosphate (ADP) inhibition and determine if platelet transfusion reduces platelet dysfunction and affects outcome. METHODS: Prospective thromboelastography (TEG) assays were collected on adult patients with TBI with intracranial injuries detected by computed tomography (CT). Outcomes included in-hospital mortality, and CT lesion expansion. RESULTS: Of 153 patients, ADP inhibition was increased in moderate and severe TBI compared to mild TBI (p = 0.0011). P2Y12 inhibiting medications had increased ADP inhibition (p = 0.0077). Admission ADP inhibition was not associated with in-hospital mortality (p = 0.24) or CT lesion expansion (p = 0.94). Mean reduction of ADP inhibition from platelet transfusion (-15.1%) relative to no transfusion (+ 11.7%) was not statistically different (p = 0.0472). CONCLUSIONS: Mild TBI results in less ADP inhibition compared to moderate and severe TBI, suggesting a dose response relationship between TBI severity and degree of platelet dysfunction. Further, study is warranted to determine efficacy and parameters for platelet transfusion in patients with TBI.

Anaemia worsens early functional outcome after traumatic brain injury: a preliminary study.

OBJECTIVE: To determine early effects on outcome from traumatic brain injury (TBI) induced by controlled cortical impact (CCI) associated with anaemia in mice. HYPOTHESIS: Outcome from TBI with concomitant anaemia would be worse than TBI without anaemia. METHODS: CCI was induced with electromagnetic impaction in four groups of C57BL/6J mice: sham, sham+anaemia; TBI; and TBI+anaemia. Anaemia was created by withdrawal of 30% of calculated intravascular blood volume and saline replacement of equal volume. Functional outcome was assessed by beam-walking test and open field test (after pre-injury training) on post-injury days 3 and 7. After functional assessment, brains removed from sacrificed animals were pathological reviewed with haematoxylin and eosin, cresyl violet, Luxol Fast Blue, and IBA-1 immunostains. RESULTS: Beam-walking was similar between animals with TBI and TBI+anaemia (p = 0.9). In open field test, animals with TBI+anaemia walked less distance than TBI alone or sham animals on days 3 (p < 0.001) and 7 (p < 0.05), indicating less exploratory and locomotion behaviours. No specific pathologic differences could be identified. CONCLUSIONS: Anaemia associated with TBI from CCI is associated with worse outcome as measured by less distance travelled in the open field test at three days than if anaemia is not present.

The effects of anaemia and transfusion on patients with traumatic brain injury: A review.

BACKGROUND: Anaemia in traumatic brain injury (TBI) is frequently encountered. Neurosurgical texts continue to recommend transfusion for hematocrit below 30%, despite clear evidence to do so. Transfusion should increase oxygen delivery to the brain, but it may also increase morbidity and mortality. METHODS: This study reviewed the relevant literature to better understand the risks of anaemia and benefits of correction of anaemia by transfusion. RESULTS: Of the 21 studies reviewed, eight found that anaemia was harmful to patients with TBI; five found no significant outcome; seven found transfusion was associated with higher rates of morbidity and mortality; two found that transfusion lowered mortality and increased brain tissue oxygen levels; and ten found no correlation between transfusion and outcome. However, the levels of anaemia severity and the outcome measurements varied widely and the majority of outcomes focused on crude measurements rather than detailed functional assessments. CONCLUSIONS: No division of response based on gender difference or impact of anaemia in the post-hospital treatment setting was observed. A randomized control trial is recommended to determine the impact of anaemia and transfusion on detailed outcome assessment in comparison of transfusion thresholds ranging from ≤ 7 g dL-1 to ≤ 9 g dL-1 in patients with moderate-to-severe TBI.

Successful treatment of dysgeusia after middle-ear surgery with amitriptyline: Case report.

INTRODUCTION: The chorda tympani branches off of the facial nerve within the petrous portion of the temporal bone, and is responsible for controlling the taste in the anterior two-thirds of the tongue on each side. Due to its location, it is commonly injured during middle-ear surgery resulting in dysgeusia. METHOD: A case of a 59-year-old male had recurrent otitis media resulting in tympanic membrane perforation. Patient subsequently underwent lateral graft tympanoplasty. Shortly after surgery patient reported onset of dysgeusia consisting of metallic taste at the tip of the tongue and salty taste on the left side of the tongue. RESULTS: Treatment with Amitriptyline 50mg each night significantly improved the patient's symptoms of dysgeusia. CONCLUSIONS: Amitriptyline may be an effective treatment for dysgeusia occurring after middle-ear surgery.

Diagnosis and Management of Pineal Germinoma: From Eye to Brain.

Pineal germinomas can be very complex in terms of presentation, diagnosis, and management. This review attempts to simplify this complexity in an organized manner, addressing the anatomic relationships that provide the basis for the uniqueness of pineal germinoma. Ocular findings and signs and symptoms of elevated intracranial pressure are the keys to suspecting the diagnosis and obtaining the necessary imaging and cerebrospinal fluid studies. Other symptoms can suggest spread beyond the pineal region. Surgery may only be needed to obtain tissue for a definitive diagnosis, as germinoma is highly responsive to chemotherapy and focused radiation therapy. Hydrocephalus, usually related to tumor obstruction of the cerebral aqueduct, may also need to be addressed. Outcome for pineal germinoma is usually excellent, but relapse can occur and may require additional intervention. These issues are detailed in this review.

No Link Between Inadvertent Surgical Glove Contamination and Surgical Site Infection in Patients Undergoing Elective Neurosurgical Operations.

INTRODUCTION: Controllable factors associated with surgical site infections (SSIs) have focused on reducing contamination of the surgical field with potential pathogens. The aim of this prospective study is to determine the incidence of glove contamination in a series of elective neurosurgical operations and determine the relationship of such glove contamination to subsequent SSI. We hypothesize that contamination of surgical gloves is associated with subsequent SSI. METHODS: In this prospective quality improvement study, gloves of the surgical team were swabbed for standard culture just prior to wound closure of elective neurosurgical operations. Patient characteristics, surgical details, and occurrence of subsequent SSIs were collected retrospectively from the electronic medical records. Data were analyzed with χ2 with Fisher's exact test and Student's t test. RESULTS: Surgical glove contamination occurred in 10 of 96 elective neurosurgical cases (10.4%). SSIs occurred in 6 cases (6.2%), but no SSI occurred in a case in which surgical glove contamination occurred (P = 1). SSI was associated with younger patient age (P = 0.0448), and surgical glove contamination was associated with less resident experience (P = 0.0354). CONCLUSIONS: Surgical glove contamination identified at the time of wound closure does not correlate with the development of subsequent SSI in elective neurosurgical operations.

Effectiveness of Standard Margin Stereotactic Radiosurgery Dose to Brain Metastases.

BACKGROUND: This study aims to assess efficacy of a 15-Gy margin dose in terms with the hypothesis that efficacy will be comparable with historical controls with fewer radiation-related side effects. METHODS: Patients who received single-fraction stereotactic radiosurgery (SRS) for metastatic brain tumors (prescribed 1500 cGy with 2-mm planning tumor volume) at the University of Missouri Hospital between 2004 and 2018 with at least 3 months of follow-up were retrospectively reviewed. Demographics, lesion dimensions, concurrent therapy, and treatment history before SRS were assessed. Outcomes included local control, distant control, radiation-related changes, survival, repeat SRS or whole-brain radiation therapy, and side effects. Data from the literature were pooled for a meta-analysis. RESULTS: A total of 142 patients had at least 3 months of follow-up data available. The 12-month actual local control rate among these patients was 92% per tumor. The overall intracranial control rate was 66.9% per patient. Radiation-related side effects occurred in 32.4% of patients (n = 46), with some patients having more than 1 side effect. Radiation-related radiographic changes occurred in 48 lesions (10.6%) in 37 patients (26%). Pathologically confirmed radiation necrosis occurred in 19 lesions (4%) and in 18 patients (12.6%). Local and distant control rates for this population was comparable with historical controls. Side effects in the literature are inconsistently reported, so rigorous comparative analysis is not possible. CONCLUSIONS: A single-fraction radiosurgery margin dose of 15 Gy to the planning tumor volume can effectively provide local control and distant control and is comparable with historical controls, which use 18-25 Gy, with a good toxicity profile.

Phase I single center trial of ketogenic diet for adults with traumatic brain injury.

BACKGROUND: Traumatic Brain injury (TBI) is a major cause of mortality and morbidity in the United States. Ketogenic diet (KD) has been shown to have neuroprotective effects in acute brain injury, but limited data about its use in adult TBI patients is available. The objective of this study is to investigate the feasibility and safety of ketogenic diet (KD) for adult TBI patients in the Neuroscience Intensive Care Unit (NSICU). METHODS: TBI patients admitted to NSICU between June 2019 to March 2021 were enrolled in this single-center, open label, single-arm prospective intervention study. The primary feasibility outcome was achievement of ketosis (detection and maintenance of serum beta-hydroxybutyrate (BOB) levels above normal); secondary outcomes included laboratory and clinical adverse effects related to KD. RESULTS: 10 adults with TBI with Abbreviated Injury Score (AIS)-Head ≥3 and ventriculostomy catheter to monitor intracranial pressure met inclusion/exclusion criteria and were placed on KD. Mean age was 47 years, and all patients were male. Eight out of 10 patients achieved ketosis within mean 2.2 days. KD was initiated within 8-33 h (average 23 h) of hospital admission. No clinical adverse effects were noted, 2 patients developed hypertriglyceridemia and 1 patient developed hypoglycemia. Serum glucose showed a decreasing trend in most patients. CONCLUSIONS: This pilot study shows that KD is feasible in the management of TBI patients. A randomized controlled trial (RCT) is justified to further understand the optimal serum BOB levels, dose and duration of KD in TBI and its effect on the outcome. CLINICALTRIALS. GOV IDENTIFIER: NCT03982602, Registered 06/11/2019, https://clinicaltrials.gov/ct2/show/NCT03982602?term=brain+injury&cond=ketogenic+diet&draw=2&rank=3.

Bifrontal Osteoplastic Flap: An Option to Decrease Infection in Bifrontal Craniotomies with Skull Base Osteotomies.

Infection can be a common complication following bifrontal craniotomy with skull base osteotomies given the potential violation of sinuses and entry into the nasal structures. Our objective was to examine our series of patients who underwent a bifrontal craniotomy with skull base osteotomies and describe the infection rate. We propose the bifrontal osteoplastic flap as an adjunct to infection prevention. A retrospective single-center study of a patient database was performed. Twenty patients were identified. Fifty-five percent were male. The mean age was 55.7 ± 13.9 years. The most common indications for surgery were esthesioneuroblastomas (35%) and anterior skull base meningiomas (30%). Six patients (30%) developed an infection, 1 patient (5%) developed a CSF leak, and no patients developed a mucocele. All 6 infected cases had nasal pathology with intracranial extension, they all received chemoradiation post-operatively and were all combined cases with otorhinolaryngology. Eighty-three percent of these patients required a craniectomy and all of them required long-term IV antibiotics. Infection is not uncommon after a bifrontal craniotomy with skull base osteotomies and the use of the bifrontal osteoplastic flap in cases where the risk of infection is high, i.e., esthesioneuroblastomas surgery, may help reduce said risk and lead to better patient outcomes.

Linac-based hypofractionated stereotactic radiotherapy for metastases involving the brainstem.

The long-term efficacy and complications of hypofractionated stereotactic radiotherapy (hSRT) to metastases involving the brainstem are not well reported. Our objective is to review the results of metastases intrinsic to or abutting the brainstem treatedwith hSRT.Patients treated with hSRT in 5 fractions at our institution from 2016 to 2020 were retrospectively reviewed. Varian Eclipse v13.7 TPS was used for treatment planning. MRI images were fused with CT images acquired at the time of simulation, and contoured structures include the brainstem, the GTV, and a 2 mm margin was used to generate the PTV. MR imaging was performed at 3-month intervals. Survival was assessed at the last available follow-up; tumor control was assessed at 6 and 12 months and toxicity was assessed based on the Radiation Therapy Oncology Group grading system at regular follow-up. Twenty patients were treated with 5 fraction treatment dose plans ranging from 20 Gy - 31.25 Gy. GTV mean volume was 3.5 cc ±â€¯4.3 cc (range 0.1 cc - 18.9 cc). The median overall survival was 6.5 months (range: 1 to 29 months). The twelve-month tumor control rate was 80%. Toxicity was generally mild, with only one patient demonstrating Grade 3 toxicity. Two patients had radiographic progression, but neither required surgical intervention. In our series, hSRT resulted in similar rates of survival, tumor control, and toxicity as compared with published single fraction series. Dose escalation of lesions adjacent to the brainstem can be considered and maybe more feasible with a hypofractionated regimen of 5 fractions.

Squamous Cell Carcinoma of the Temporal Bone Arising from Cholesteatoma: A Case Report and Review of the Literature.

Objective Present a case of squamous cell carcinoma of the temporal bone (SCCTB) arising in a 61-year-old female with a prior history of cholesteatoma and persistent otologic symptoms and review the current literature regarding this disease presentation. Setting Tertiary academic center. Patient A 61-year-old female with a history of left ear cholesteatoma for which she had undergone surgery 54 years prior. The patient presented with a persistent history of otorrhea since first surgery and developed exacerbation of symptoms just prior to presentation at our department. The clinical picture was highly suspicious of cholesteatoma recurrence. However, the biopsy was consistent with squamous cell carcinoma. Intervention Surgical debulking of the lesion was followed by a brief course of radiation therapy later halted by the patient due to side effect intolerance. Conclusion SCCTB may arise from cholesteatoma. A high index of suspicion for SCCTB should be maintained in patients with a prior history of cholesteatoma and evidence of a temporal bone mass with persistent otologic symptoms.

Isolation and characterization of a population of stem-like progenitor cells from an atypical meningioma.

The majority of meningiomas are benign tumors associated with favorable outcomes; however, the less common aggressive variants with unfavorable outcomes often recur and may be due to subpopulations of less-differentiated cells residing within the tumor. These subpopulations of tumor cells have tumor-initiating properties and may be isolated from heterogeneous tumors when sorted or cultured in defined medium. We report the isolation and characterization of a population of tumor-initiating cells derived from an atypical meningioma. We identify a tumor-initiating population from an atypical meningioma, termed meningioma-initiating cells (MICs). These MICs self-renew, differentiate, and can recapitulate the histological characteristics of the parental tumor when transplanted at 1000 cells into the flank regions of athymic nude mice. Immunohistochemistry reveals stem-like protein expression patterns similar to neural stem and progenitor cells (NSPCs) while genomic profiling verified the isolation of cancer cells (with defined meningioma chromosomal aberrations) from the bulk tumor. Microarray and pathway analysis identifies biochemical processes and gene networks related to aberrant cell cycle progression, particularly the loss of heterozygosity of tumor suppressor genes CDKN2A (p16(INK4A)), p14(ARF), and CDKN2B (p15(INK4B)). Flow cytometric analysis revealed the expression of CD44 and activated leukocyte adhesion molecule (ALCAM/CD166); these may prove to be markers able to identify this cell type. The isolation and identification of a tumor-initiating cell population capable of forming meningiomas demonstrates a useful model for understanding meningioma development. This meningioma model may be used to study the cell hierarchy of meningioma tumorogenesis and provide increased understanding of malignant progression.

Daily Lifestyle Modifications to Improve Quality of Life and Survival in Glioblastoma: A Review.

Survival in glioblastoma remains poor despite advancements in standard-of-care treatment. Some patients wish to take a more active role in their cancer treatment by adopting daily lifestyle changes to improve their quality of life or overall survival. We review the available literature through PubMed and Google Scholar to identify laboratory animal studies, human studies, and ongoing clinical trials. We discuss which health habits patients adopt and which have the most promise in glioblastoma. While results of clinical trials available on these topics are limited, dietary restrictions, exercise, use of supplements and cannabis, and smoking cessation all show some benefit in the comprehensive treatment of glioblastoma. Marital status also has an impact on survival. Further clinical trials combining standard treatments with lifestyle modifications are necessary to quantify their survival advantages.

Complex Multidisciplinary Cranial and Scalp Reconstruction for Patient Salvage.

OBJECTIVE/BACKGROUND: Patients can develop scalp and cranial defects as a result of neoplasm, trauma, or infection. Reconstruction of these defects can be difficult in some patients and may require a multidisciplinary approach using creative solutions usually used for disease processes in other areas of the body, such as severe burns. METHODS: A series of 9 patients were treated using multidisciplinary techniques for reconstruction of complex cranial and scalp defects. Data on patient characteristics, initial treatment, and preparatory and definitive reconstructive treatment were retrospectively collected. Outcomes were measured as full solution, partial solution, or failure. RESULTS: Three patients had a full solution/wound closure, 5 had a partial solution, and 1 failed reconstructive attempt. Full solution patients tended to be younger, received reconstruction treatment modalities for longer periods of time, and had more definitive surgeries. Initial and preparatory surgeries did not tend to promote a full solution, though having fewer preparatory surgeries that were not related to wound vacuum-assisted closure use tended to be associated with a better outcome. Infection of the scalp or cranium did not tend to change the result. CONCLUSIONS: Reconstructive salvage of complex cranial and scalp defects takes time, so patience and earlier recognition of need for atypical reconstruction is beneficial. Patient characteristics may influence outcomes, but judicious choice of materials and techniques is more critical to patient success. Use of a multidisciplinary approach to complex cranial and scalp reconstruction is a beneficial option for many patients for whom standard reconstruction methods are not viable.

Severity of Preoperative HbA1c and Predicting Postoperative Complications in Spine Surgery.

BACKGROUND: Diabetes mellitus (DM) is associated with a greater incidence of perioperative complications. The measurement of hemoglobin A1c (HbA1c) has not been routinely used in the preoperative assessment for spine surgeries. METHODS: In the present single-institution, prospective study, HbA1c testing was included in the preoperative laboratory examination of patients undergoing spinal surgery from 2016 through 2018. The HbA1c levels were categorized using the American Diabetes Association guidelines as normal (HbA1c <5.7%), pre-DM (HbA1c 5.7%-6.4%), and diabetes (HbA1c >6.5%). Those with a HbA1c of ≥8% were separated as having poorly controlled DM for analysis. Perioperative complication and comorbidity data were collected to assess for associations with DM using logistic regression models. Odds ratios (ORs) and 95% confidence intervals were computed. RESULTS: A total of 440 patients (238 men, mean age, 56.43 ± 13.28 years; mean body mass index, 30.80 ± 6.65 kg/m2) met the study criteria. The HbA1c was <5.7% in 206 patients (46.8%), 5.7%-6.4% in 148 (33.6%), 6.5%-7.9% in 64 (14.5%), and ≥8.0% in 23 patients (5.22%). Bivariate logistic modeling showed that patients with poorly controlled DM had a higher risk of complications (OR, 2.92) than did the patients with DM (OR, 2.13). Malignancy (OR, 2.62) and hypertension (OR, 1.86) were also significant risk factors for complications. However, smoking (OR, 0.83) was not significant. Poorly controlled DM remained associated with complications in multivariable logistic regression modeling (OR, 2.72). CONCLUSIONS: Poorly control DM defined by the preoperative HbA1c was significantly associated with postoperative complications. Smoking, however, was not so associated. Preoperative HbA1c can be used to assess the risk of postoperative spine surgery complications.

Isolated Primary Sinonasal Adenocarcinoma of the Sphenoid Sinus.

Isolated lesions of the sphenoid sinus, particularly malignancies, are rarely reported and exist largely within the Otolaryngology literature. Delayed diagnosis may necessitate neurosurgical involvement; therefore, neurosurgeons must be aware of the range of pathologies in this region in order to provide adequate treatment. We present an unusual case of an 89-year-old female with several weeks of worsening headaches, vision loss, and cranial neuropathies. Work-up at an outside hospital was non-diagnostic. After referral, an expansive and erosive lesion within the left sphenoid sinus was identified. A transsphenoidal approach for resection of the lesion yielded a primary non-salivary non-intestinal type sinonasal adenocarcinoma, as well as bacterial sinusitis and probable allergic fungal sinusitis. The patient was treated with antimicrobial medications as well as stereotactic radiosurgery. Her neurological deficits did not improve with treatment, and she ultimately expired 3.5 months post-operatively after transition to hospice. Primary sinonasal adenocarcinoma is a very rare pathology in this location. Surgical intervention is necessary to obtain an accurate diagnosis and proceed with appropriate treatment. Delayed diagnosis likely portends a worse prognosis.

The impact of poor post-operative glucose control on neurosurgical surgical site infections (SSI).

Elevated HbA1c is associated with increased surgical site infections (SSI) in neurosurgical patients. How blood glucose control in the early post-operative period relates to SSI is incompletely understood. We hypothesized that poor early post-operative blood glucose control would be associated with SSI. Data from patients undergoing neurosurgical procedures at University of Missouri Hospital was retrospectively collected. Post-operative blood glucose for 72 h after surgery was assessed and categorized by levels of hyperglycemia; those with glucose ≥200 mg/dl were classified as poorly controlled. Patients with SSI were compared to patients without SSI using Chi-Square test with Fisher's exact test when appropriate. Of 500 patients having surgery, 300 had at least one post-operative blood glucose measurement. Of those 300 patients, 19 (6.33%) developed SSI. Patients with SSI had significantly higher mean post-operative blood glucose levels (p = 0.0081) and a greater mean number of point-of-care glucose level measurements >150 mg/dL (p = 0.0434). Pre-operative HbA1c and SSI were not associated (p = 0.0867). SSI was associated with pre-operative glucocorticoid use (p = 0.03), longer operative procedure (p = 0.0072), and required use of post-operative insulin drip (p = 0.047). Incidence of other wound complications (cellulitis, deep infection, dehiscence) increased with increase in post-operative blood glucose levels to >225 mg/dL. Post-operative hyperglycemia is associated with SSI after neurosurgical procedures, emphasizing the importance addressing blood glucose control after surgery.

Pineal cysts: Does anyone need long-term follow up?

Pineal cysts are a common incidental finding on brain magnetic resonance imaging (MRI) whichfrequently prompts referral to neurosurgery. Currently, a management algorithm for patientswithout hydrocephalus, Parinaud's syndrome, or pineal apoplexy is lacking.We aimed to identifypredictive factors of pineal cyst volume change andsurgical intervention by performing retrospective chart review of 98 patients between 2005 and 2018 diagnosed with pineal cysts gleaned from our Neurosurgery clinical databases.We included patients whose initial and follow-up MRIs were available in our institutional radiology system or whose surgical pathology confirmed pineal cyst after evaluation with an initial MRI. Patients' medical records were queried for presenting symptoms, demographic, management, and pineal cyst measurements. Three dimensions (anterior-posterior, rostral-caudal, transverse) of pineal cyst size were measured and converted to cyst volume (cm3) for analysis. Fifty-five patients (mean age 26.09 ± 14.7 years) with pineal cysts met study criteria. Follow-up ranged from 4 months to 10 years. The indications for MR imaging included headache (81.8%) and vision problems (42%).Forty-eight patients who were observed had a mean volume change of 0.051 ± 0.862 cm [3] and median volume change of 0 cm [3] Patient symptoms, referral source, and age were not associated with changes in volume on follow-up. Aggregated number of symptoms did not differ between operative and observation patients. (p = 0.29). Pineal cyst volumes tend to remain stable over serial MR images, do not reliably correlate with symptoms, and do not typically require long-term follow-up.

Reliability of Magnetic Resonance Spectroscopy and Positron Emission Tomography Computed Tomography in Differentiating Metastatic Brain Tumor Recurrence from Radiation Necrosis.

BACKGROUND: Clinical and/or neuroimaging changes after whole-brain radiation therapy (WBRT) or stereotactic radiosurgery (SRS) for metastatic brain tumor(s) present the clinical dilemma of differentiating tumor recurrence from radiation necrosis. Several imaging modalities attempt to answer this clinical question, including magnetic resonance spectroscopy (MRS) and positron emission tomography (PET) computed tomography (CT). We evaluated our experience regarding the ability of MRS and PET CT to differentiate tumor recurrence from radiation necrosis in patients who have received WBRT or SRS. METHODS: We retrospectively reviewed records of 242 patients with previous WBRT or SRS to identify those who had MRS and/or PET CT to differentiate tumor recurrence from radiation necrosis. Patients were sorted into true-positive, false-positive, false-negative, and true-negative groups on the basis of imaging interpretation and clinical course combined with surgical pathology results or reaction to nonsurgical treatments including SRS, dexamethasone, or observation. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were then calculated. RESULTS: Of 25 patients presenting such diagnostic questions, 19 were evaluated with MRS and 13 with PET CT. MRS sensitivity was 100%, specificity was 50%, and accuracy was 81.8%, whereas PET CT sensitivity was 36.4%, specificity was 66.7%, and accuracy was 42.9%. CONCLUSIONS: MRS has better accuracy than PET CT and a high negative predictive value, therefore making it more useful in distinguishing recurrent tumor from radiation necrosis. We encourage correlation with symptoms at imaging to aid in clinical decision making.