Preoperative Imaging Protocol Research Articles

WP1.17 - Double Trouble - A Case of Duplex Appendix

Abstract Introduction Duplex appendix, a rare anatomical anomaly is often encountered incidentally during appendicectomy procedures. It is characterised by the presence of two appendiceal lumens and can be classified using the Cave-Wallbridge classification system. Case An 18-year-old male presents to the Emergency Department with a two-day history of migratory right iliac fossa pain. He was consented and booked for a laparoscopic appendicectomy based on clinical suspicion of acute appendicitis. Intra-operatively, an unexpected finding surfaces—a second pendunculated mass adjacent to the inflamed appendix. Employing laparoscopic linear staples, both the appendix and the adjacent mass were divided. One day post-discharge, the patient presents with severe abdominal pain and computed tomography imaging suggests an intra-abdominal leak. The patient underwent an emergency laparotomy and ileo-caecal resection overnight. Histology revealed the second pedunculated mass was indeed a second appendix, a phenomenon with a reported incidence of 0.004 to 0.009%. Discussion Addressing the nuances of using imaging modalities in the diagnosis and operative planning of acute appendicitis, our discussion raises pertinent questions regarding the necessity of definitive pre-operative imaging in suspected cases. Considering potential pitfalls of incorrect clinical diagnoses; the presence of anatomical anomalies; and other factors influencing surgical decision-making; we scrutinise the proposition of pre-operative imaging protocols in suspected acute appendicitis. Conclusively our case encapsulates the diagnostic and therapeutic conundrums posed by duplex appendix instances, prompting a deeper exploration into the use of imaging techniques in a traditionally clinically diagnosed presentation and the implications thereof in surgical management.

Four-Dimensional Computed Tomography for Parathyroid Adenoma Localization: A Pre-Operative Imaging Protocol.

Primary hyperparathyroidism (PHPT) affects approximately 0.86% of the population, with surgical resection as the treatment of choice. A 4D computed tomography (CT) is a highly effective tool in localizing parathyroid adenomas; however, there is currently no defined role for 4D CT when stratified against ultrasonography (USG) and nuclear medicine Technetium Sestamibi SPECT/CT (SES) imaging. Retrospective Study. University Hospital. All patients who underwent parathyroidectomy for PHPT between 2014 and 2019 at a single institution were reviewed. Patients who had a 4D CT were included. We compared outcomes of 4D CT as a second line imaging modality to those of USG and SES as first line modalities. An imaging algorithm was proposed based on these findings. There were 84 patients identified who had a 4D CT after unsuccessful first line imaging. A 4D CT localized parathyroid adenoma to the correct quadrant in 64% of cases, and to the correct laterality in 75% of cases. Obese patients had significantly lower rates of adenoma localization with USG (33.4%), compared to non-obese patients (67.5%; P = .006). In determining multigland disease the sensitivity of 4D CT was 86%, while the specificity was 87%. A 4D CT has impressive rates of accurate localization of parathyroid adenomas; however due to the radiation exposure involved, it should remain a second line imaging modality. PHPT patients should first be evaluated with USG, with 4D CT used if this is unsuccessful and patients are greater than 40 years old, have a high BMI, or are having revision surgery.

EVALUATION OF ANATOMICAL VARIATIONS OF EXTRARENAL RENAL ARTERIAL VASCULATURE IN VOLUNTARY KIDNEY DONORS

Objective: The present study was aimed at evaluating the variations in extrarenal renal arterial vasculature in voluntary kidney donors who had undergone Multi-Detector Computed Tomography (MDCT) renal angiography for preoperative workup. Methods: A retrospective hospital based cross-sectional study was carried out in a tertiary care Army hospital in Delhi from Jan 2019 to June 2020. All voluntary kidney donors included in the study underwent Multi-Detector Computed Tomography Angiography (MDCTA) of renal arteries as a part of routine pre-operative imaging protocol and were referred by the treating physician/surgeon for MDCTA study. Retrospective analysis of the image datasets was undertaken by the principal investigator and individual patient consent was waived off by the institutional Ethics committee. Results: The mean age of study participants was 45.9±10.2 y. Accessory renal artery was relatively more common on left side (p-value 0.001). There was statistically no significant difference between gender and the presence of accessory renal artery. There was statistically no significant difference on the comparison of side and gender with distance of segmentary bifurcation of MRA. The orthogonal diameters at the origin of the MRA and accessory renal artery on both sides were also comparable. Origin of accessory renal arteries were caudal to MRA was more frequently seen. Early segmentary bifurcation of MRA was commoner on the right side. Conclusion: The study emphasizes the importance of meticulous preoperative assessment, highlighting the need for surgeons to be cognizant of the potential variations in extrarenal renal artery anatomy. Such awareness is crucial for planning successful kidney transplant surgeries.

A narrative review of treatment strategies for major glenoid defects during primary reverse shoulder arthroplasty, with a focus on the use of structural bone graft.

Structural glenoid defects are common during primary reverse shoulder arthroplasty (RSA) and are often associated with poor outcomes. The lack of pre-operative imaging protocols for determining the depth and degree of glenoid wear hinders our ability to accurately plan and correct these defects. Although bone grafting has been reported to be effective in reducing glenoid wear during RSA, there is limited information on when to utilise it and how to prepare the graft. We conducted this review to assess the evidence for the management of glenoid defects, with an emphasis on bone grafts to treat structural glenoid bone loss in primary RSA patients.

Intraoperative diagnosis of facial schwannomas: a multicenter summation of clinical experience, preoperative avoidance, and intraoperative management protocol.

Preoperative differentiation of facial nerve schwannoma (FNS) from vestibular schwannoma (VS) can be challenging, and failure to differentiate between these two pathologies can result in potentially avoidable facial nerve injury. This study presents the combined experience of two high-volume centers in the management of intraoperatively diagnosed FNSs. The authors highlight clinical and imaging features that can distinguish FNS from VS and provide an algorithm to help manage intraoperatively diagnosed FNS. Operative records of 1484 presumed sporadic VS resections between January 2012 and December 2021 were reviewed, and patients with intraoperatively diagnosed FNSs were identified. Clinical data and preoperative imaging were retrospectively reviewed for features suggestive of FNS, and factors associated with good postoperative facial nerve function (House-Brackmann [HB] grade ≤ 2) were identified. A preoperative imaging protocol for suspected VS and recommendations for surgical decision-making following an intraoperative FNS diagnosis were created. Nineteen patients (1.3%) with FNSs were identified. All patients had normal facial motor function preoperatively. In 12 patients (63%), preoperative imaging demonstrated no features suggestive of FNS, with the remainder showing subtle enhancement of the geniculate/labyrinthine facial segment, widening/erosion of the fallopian canal, or multiple tumor nodules in retrospect. Eleven (57.9%) of the 19 patients underwent a retrosigmoid craniotomy, and in the remaining patients, a translabyrinthine (n = 6) or transotic (n = 2) approach was used. Following FNS diagnosis, 6 (32%) of the tumors underwent gross-total resection (GTR) and cable nerve grafting, 6 (32%) underwent subtotal resection (STR) and bony decompression of the meatal facial nerve segment, and 7 (36%) underwent bony decompression only. All patients undergoing subtotal debulking or bony decompression exhibited normal postoperative facial function (HB grade I). At the last clinical follow-up, patients who underwent GTR with a facial nerve graft had HB grade III (3 of 6 patients) or IV facial function. Tumor recurrence/regrowth occurred in 3 patients (16%), all of whom had been treated with either bony decompression or STR. Intraoperative diagnosis of an FNS during a presumed VS resection is rare, but its incidence can be reduced further by maintaining a high index of suspicion and undertaking further imaging in patients with atypical clinical or imaging features. If an intraoperative diagnosis does occur, conservative surgical management with bony decompression of the facial nerve only is recommended, unless there is significant mass effect on surrounding structures.

Deferring gonadectomy in patients with turner syndrome with a genetic Y component is not a safe practice

Patients with Turner syndrome who harbor Y chromosome material are known to be at increased risk of developing germ cell neoplasms. The optimal timing to perform gonadectomy to reduce the risk of cancer development in these patients is not well defined. We present outcomes of Turner with a Y component (TSY) patients who underwent gonadectomy at our institution. We hypothesized that tumors could occur in a significant portion of TSY patients at any age and gonadectomy can be safely performed at diagnosis rather than deferred. We performed an IRB-approved retrospective single center study in which we queried our institutions electronic health record to identify all patients with TSY who underwent gonadectomy at our institution from 2012 to 2021. In our series of 18 consecutive TSY patients, a tumor was identified in 6 patients (33.3%): 4 (22.2%) with dysgerminoma (DG) [Fig.1] and 2 (11.1%) with gonadoblastoma (GB). Our cohort of 18 consecutive TSY who underwent gonadectomy over a 9-year period is the largest published single site cohort to date. Additionally, our patient who was found to have GB at 40 days is to our knowledge the youngest TSY patient to be diagnosed with GB in the literature. This patient's remarkably early incidence of tumor occurrence illustrates the urgency of protective gonadectomy. Given the high incidence of tumor formation in this population and the minimal morbidity associated with gonadectomy, we do not recommend delaying gonadectomy in this population for any reason. Our study is vulnerable to selection bias and confounding innate to any retrospective study. There was variation with respect to the frequency and timing of pre-operative imaging as a strict preoperative imaging protocol with sequential studies was not in place at our institution. Additionally, we do not have a comparison cohort of patients who are being followed without operative intervention as all TSY patients at our institution have undergone gonadectomy. TSY patients cannot be safely observed for tumor formation based on clinical factors such as imaging or age. Gonadectomy is safe with a low complication rate and without tumor recurrence during three-year follow-up. We continue to recommend bilateral gonadectomy in this patient population at the time of diagnosis.

Partial anomalous pulmonary venous return after orthotopic heart transplantation case report

BackgroundPartial anomalous pulmonary venous return (PAPVR) is a congenital heart defect. Reports of repair and treatment in pediatric cases have been published, but incidence of PAPVR in adults is not common. To our knowledge, there has not been a diagnosis of left-sided PAPVR after a heart transplant an in adult patient.Case presentationA 62-year-old patient with ischemic cardiomyopathy and systolic heart failure underwent orthotopic heart transplantation. The immediate post-operative course was remarkable for an elevated cardiac index and pulmonary artery pressures as well as decreased systemic vascular resistance. The post-operative echocardiogram did not reveal an intra-cardiac shunt. However, computed tomographic angiography (CTA) showed a left superior pulmonary vein draining into the innominate vein. Operative repair of the left superior pulmonary venous connection to the left atrial appendage was completed under cardiopulmonary bypass with beating heart. Her hemodynamics improved immediately, and she had an unremarkable postoperative course.ConclusionsWhile uncommon, any patient with a high cardiac output and abnormal hemodynamics after heart transplant should be evaluated for the existence of a shunt. While not a part of all traditional preoperative imaging protocols, a chest CTA should be considered if PAPVR is suspected as it can both diagnose the condition and enable a plot of the corrective course of surgical action.

Improved targeting of the globus pallidus interna using quantitative susceptibility mapping prior to MR-guided focused ultrasound ablation in Parkinson's disease

PurposeMagnetic resonance guided focused ultrasound (MRgFUS) of the globus pallidus interna (GPi) has shown promise in the treatment of drug-resistant Parkinson's disease, though direct visualization of the GPi remains challenging with MRI. The purpose of this study was to compare various preoperative MR imaging techniques and to evaluate the utility of quantitative susceptibility imaging (QSM) in the depiction of the GPi prior to MRgFUS ablation. Materials and methodsSix patients with medication refractory advanced idiopathic Parkinson's disease were referred for preoperative MR imaging prior to MRgFUS pallidotomy. Axial T1WI and T2WI, Fast Gray Matter Acquisition T1 Inversion Recovery (FGATIR), and QSM sequences were acquired. DTI tractography was performed to delineate the corticospinal tracts. Qualitative visualization scores and contrast to noise ratios (CNR) were recorded and measured on all images. ResultsQSM had significantly higher median qualitative visualization scores (3.00) compared with the T1WI (1.00), T2WI (1.50), and FGATIR sequences (1.50) (p < 0.05). QSM provided superior CNR for GPi depiction in each category (GPi-GPe and GPi-IC), respectively. For GPi-GPe, median CNR for T1WI, T2WI, FGATIR, and QSM was 1.13, 1.68, 0.79, and 10.78. For GPi-IC, median CNR for T1WI, T2WI, FGATIR, and QSM was 1.48, 4.63, 4.24, and 40.26, respectively (p < 0.05). ConclusionQSM offers improved visualization of the GPi compared with the traditional and currently recommended MR sequences prior to MRgFUS ablation in patients with Parkinson's disease. These results suggest that QSM should be considered as part of all preoperative imaging protocols prior to MRgFUS pallidotomy.

Automated 3-Dimensional Magnetic Resonance Imaging Allows for Accurate Evaluation of Glenoid Bone Loss Compared With 3-Dimensional Computed Tomography

To evaluate clinical measurements of glenoid bone loss based on 3-dimensional (3D) computed tomography (CT) and automatically segmented 3D reconstructions from Dixon fat-water magnetic resonance (MR) imaging. Available CT and MR studies from 16 patients with recurrent anterior shoulder instability were retrospectively reviewed. Three-dimensional reconstructions were formed independently by 2 observers using freely available software and a simple threshold-based segmentation (3D Slicer, version 4.8.0; http://www.slicer.org). Bone loss was estimated with the perfect-circle method. Intra-user and interuser reproducibility was determined with intraclass correlation coefficients. Bland-Altman plots were used to evaluate the similarity between imaging modalities. Differences between MR and CT estimates of bone loss ranged from 0% to 6%. The individual intraclass correlation coefficients showed good to excellent reliability, with intraobserver comparisons between MR- and CT-based bone loss estimates ranging from 0.94 to 0.99. Bland-Altman plots showed 95% confidence intervals from -5% to 6% for differences between MR and CT estimates, with 88% of all measurements (42 of 48) showing a less than 2% difference between MR and CT estimates. The described methodology for obtaining an MR-based 3D reconstruction of the glenoid can evaluate glenoid bone loss similarly to the performance of a 3D CT reconstruction. The results may allow surgeons to simplify the preoperative imaging protocol for patients with recurrent shoulder stabilization and limit the number of shoulder CT scans. Level III, retrospective therapeutic trial.

Preoperative Angiography for Free Fibula Flap Harvest: A Meta-Analysis.

The necessity for routine preoperative imaging for free fibula harvest is controversial. The primary objective of this meta-analysis is to determine if lower extremity angiography is necessary to detect abnormalities that may alter flap selection. The secondary objective is to determine if physical examination alone is sufficient to predict these abnormalities. A literature search was performed using Cochrane, CENTRAL, MEDLINE, CINAHL, and EMBASE. Studies were selected for inclusion if they included patients undergoing free fibula flap harvest with preoperative imaging, with or without physical examination findings. Data extraction was performed independently and in duplicate, including a change in flap selection and the level of agreement between physical examination and imaging. Pooled proportions were calculated using a random-effects model and 95% confidence intervals (CI). Sixteen studies were included for analysis. Mean sample size was 42 patients (range: 5-123). Included studies were of low methodologic quality. Pooled proportion of patients who had flap selection change secondary to abnormalities identified on preoperative angiography was 20.1% (95% CI: 9.6-33.2%). A pooled proportion of 71.5% (95% CI: 5-88.7%) of cases requiring change in flap selection was missed by physical examination findings alone. There is low-quality evidence suggesting a necessity for routine preoperative angiography for all patients undergoing free fibula flap harvest. Physical examination alone is insufficient in detecting vascular abnormalities that may result in limb compromise or an inability to successfully harvest a free fibula. Further investigation is warranted for cost-effectiveness of preoperative imaging protocols.

Survival and metastasis in muscle-invasive bladder cancer patients who present with indeterminate pulmonary nodules before treatment.

BACKGROUNDIndeterminate pulmonary nodules (IPNs) are common during initial evaluation of bladder cancer patients. Their significance is still unknown.OBJECTIVEDetermine the significance of indeterminate pulmonary nodules, including their size and number, in muscle-invasive bladder cancer patients before definitive local therapy by surgery or chemo-radiotherapy.DESIGNRetrospective review, single-center descriptive study.SETTINGSA tertiary cancer center.PATIENTS AND METHODSWe performed a retrospective review of patients who underwent definitive local therapy of bladder cancer by either radical cystectomy and lymph node dissection or with chemo-radiotherapy between January 1997 and December 2015. We identified patients with baseline CT scans done during staging work-up prior to definitive treatment. Patients with proven clinical metastasis at presentation were excluded, while patients who had IPNs without features suggesting metastasis were included.MAIN OUTCOME MEASURESDisease-free survival and overall survival.SAMPLE SIZE168 patients.RESULTSThe median age of patients at diagnosis was 66 years; 92% were males and 56% were smokers. IPNs (3 cm or less) were present in 74 patients (44.0%). Median follow-up was 24 months. IPNs were associated with decreased disease-free survival while IPNs did not affect the overall survival (HR=1.9; 95% CI: 1.1–3.4); P=.01 and HR=1.5; 95% CI: 1.0–2.5); P=.07, respectively. In addition, nodules >1 cm had reduced disease-free survival (HR=2.5; 95% CI: 1.1–5.9); P=.04. In the surgery group (n=126), the median number of lymph nodes excised was 14, with no association between lymph nodes status and the presence of IPNs (P=.08).CONCLUSIONThe presence of IPNs, especially nodules >1 cm had a negative effect on disease-free survival. Tailored postoperative follow-up of these patients may impact disease outcomes.LIMITATIONSThe retrospective nature, the lack of standardized preoperative imaging protocols, the lack of a central radiology review and the small number of patients.

Anatomical considerations of C2 lamina for the placement of translaminar screw: a review of the literature.

The thorough knowledge of C2 lamina anatomy is essential for the avoidance of complications during screw fixation. We performed a review of the literature, aiming to detect what was found about anatomical feasibility of C2 translaminar fixation in different populations, along with possible recommendations for the avoidance of complications, and to detect whether factors such as race or gender could influence axis lamina anatomy and fixation feasibility. We performed a search in PubMed and Cochrane database of systematic reviews for studies which correlated axis lamina anatomy with fixation feasibility. We extracted data concerning measurements on C2 lamina, the methods and conclusions of the studies. Twenty-six studies met our inclusion criteria. The studies mainly focused on Asian populations. Male gender was generally related to larger anatomical parameters of C2 lamina. The use of a C2 translaminar screw with a diameter of 3.5mm was generally feasible, even in children, but there was disagreement about risk of vertebral artery injury. Computed tomography was most frequently recommended preoperatively. Three-dimensional reconstruction was suggested by some authors. C2 lamina anatomy generally permitted screw fixation in most studies, but there was disagreement about risk of vertebral artery injury. Preoperative computed tomography was generally recommended, while, according to some authors, three-dimensional reconstruction could be essential. However, there is a relative lack of studies about non-Asian populations. More research could further illustrate the anatomy of C2 lamina, clarify the safety of axis fixation for more populations and perhaps modify preoperative imaging protocols.

Endoscopic vs Transfacial Resection of Sinonasal Adenocarcinomas

Compare the survival and the complication rates of 2 comparable groups of patients who underwent either endoscopic or transfacial resection of a sinonasal adenocarcinoma. Historical cohort study. Tertiary referral center. Twenty-four patients with sinonasal adenocarcinomas who recently underwent an endoscopy (the ENDO group, 1999-2009) were compared with 24 patients who underwent a lateral rhinotomy procedure (the LR group, 1993-2007). The present retrospective study included patients who would have had an endoscopic resection in 2011. The groups were comparable in terms of age and sex (P = .49), as well as tumor stages; 43 of the 48 patients had undergone postoperative radiotherapy. There were 13 T1-T2 and 11 T3-T4 tumors in the ENDO group compared with 12 T1-T2 and 12 T3-T4 tumors in the LR group (P = .77). The mean length of follow-up was 38 months for the ENDO group and 89 for the LR group. The overall survival and recurrence-free rates were not significantly different (P = .3 and P = .87, respectively). The median duration of hospitalization was significantly shorter in the ENDO group than in the LR group (4 vs 8 days, P < .0001). The rate of early complications was identical in both groups (12.5%). The endoscopic approach is a safe and effective treatment in selected sinonasal adenocarcinoma cases. The early oncological outcome and morbidity associated with the endoscopic approach were comparable with a transfacial approach. Hospitalization was significantly reduced by the endoscopic approach. Although the endoscopic approach is less invasive, it requires an optimal preoperative imaging protocol and an experienced surgical team.

Endoscopic vs Transfacial Removal of Sinusal Adenocarcinoma

Objective: Compare the overall survival, recurrence-free survival, and complication rates between 2 comparable groups of patients operated by an endoscopic or a transfacial resection of a sinonasal adenocarcinoma. Method: A first group of 24 patients with a sinonasal adenocarcinoma recently operated endoscopically (« ENDO », 1999-2009) is compared to another group of 24 patients operated anteriorly by a transfacial approach (lateral rhinotomy “LR” 1993-2007). In this retrospective study, we included patients who would have had in 2010 an endoscopic resection. Results: Groups were comparable in terms of age and sex ( P = .49) and tumoral stages with 13T1-T2/11T3-T4 in the group ENDO and 12T1-T2/12T3-T4 in the group LR ( P = .77). a total of 43 out of 48 patients have had a postoperative radiation therapy. The mean follow-up was respectively of 27 and 82 months for the groups ENDO and LR. After 27 months, the overall survival curves were not significantly different. The recurrence-free rates were equally similar in both groups ( P = .71). The median duration of hospitalization was significantly shorter in the ENDO group (4 vs 8 days, P &lt; .0001). The rate of early complications was strictly identical in both groups (3/24). Conclusion: The endoscopic approach is an effective treatment in selected cases of sinonasal adenocarcinomas. Early oncological outcome and morbidity are comparable to a transfacial approach. Hospitalization was significantly reduced and skin scars avoided. This procedure is less invasive but requires an optimal preoperative imaging protocol and an experienced surgical team.

Computer-assisted versus non-computer-assisted preoperative planning of corrective osteotomy for extra-articular distal radius malunions: a randomized controlled trial

BackgroundMalunion is the most common complication of distal radius fracture. It has previously been demonstrated that there is a correlation between the quality of anatomical correction and overall wrist function. However, surgical correction can be difficult because of the often complex anatomy associated with this condition. Computer assisted surgical planning, combined with patient-specific surgical guides, has the potential to improve pre-operative understanding of patient anatomy as well as intra-operative accuracy. For patients with malunion of the distal radius fracture, this technology could significantly improve clinical outcomes that largely depend on the quality of restoration of normal anatomy. Therefore, the objective of this study is to compare patient outcomes after corrective osteotomy for distal radius malunion with and without preoperative computer-assisted planning and peri-operative patient-specific surgical guides.Methods/DesignThis study is a multi-center randomized controlled trial of conventional planning versus computer-assisted planning for surgical correction of distal radius malunion. Adult patients with extra-articular malunion of the distal radius will be invited to enroll in our study. After providing informed consent, subjects will be randomized to two groups: one group will receive corrective surgery with conventional preoperative planning, while the other will receive corrective surgery with computer-assisted pre-operative planning and peri-operative patient specific surgical guides. In the computer-assisted planning group, a CT scan of the affected forearm as well as the normal, contralateral forearm will be obtained. The images will be used to construct a 3D anatomical model of the defect and patient-specific surgical guides will be manufactured. Outcome will be measured by DASH and PRWE scores, grip strength, radiographic measurements, and patient satisfaction at 3, 6, and 12 months postoperatively.DiscussionComputer-assisted surgical planning, combined with patient-specific surgical guides, is a powerful new technology that has the potential to improve the accuracy and consistency of orthopaedic surgery. To date, the role of this technology in upper extremity surgery has not been adequately investigated, and it is unclear whether its use provides any significant clinical benefit over traditional preoperative imaging protocols. Our study will represent the first randomized controlled trial investigating the use of computer assisted surgery in corrective osteotomy for distal radius malunions.Trial registrationNCT01193010

Carotid artery visualization during anterior skull base surgery: a novel protocol for neuronavigation

Detailed knowledge of the vascular anatomy of the anterior skull base is critical to successful surgery in this area. Whereas conventional neuronavigational approaches combine MRI (+/- contrast) for tumor visualization and CT (+/- C) for bony and vascular anatomy, we describe the Canadian and Austrian experiences using a novel protocol integrating MR angiography (MRA) into surgical neuronavigation to provide superior visualization of the carotid arteries. The pre-operative imaging protocol employs a T1-weighted, 3D fast spoiled gradient echo MRI (+/- C) for soft tissue anatomy, a plain CT for bony anatomy, and a 3D time-of-flight MR angiography for carotid anatomy. The series are imported into the Medtronic StealthStation((R)) TREON((R)) Treatment Guidance System; during intra-operative neuronavigation, each series (MRI, CT, MRA) can be viewed individually, or layered and viewed as a composite image. Our protocol has important advantages. First, it provides detailed tissue, tumor, vascular and bony anatomy. Second, a contrast CT is not necessary; this is important, as numerous reports have highlighted the nephrotoxic nature of radiographic contrast material. Third, visualization of the carotid system is superior than can be obtained from CT angiography. We use this unique imaging protocol routinely for our endoscopic transsphenoidal surgeries to provide superior visualization of the carotid arteries during anterior skull base surgery.

99mTc-MIBI radioguided surgery for limited invasive parathyroidectomy.

We report the preliminary results obtained with the intraoperative MIBI-guided gamma probe in a group of 9 patients with primary hyperparathyroidism (pHPT). These patients were selected for limited invasive parathyroid surgery on the basis of a preoperative imaging protocol consisting of a pertechnetate & perchlorate/MIBI scan combined with neck ultrasonography (US). In the operating room 50-70 MBq MIBI was injected 30 to 45 min before parathyroidectomy. The radioactivity was measured intraoperatively at three sites: parathyroid (P), thyroid (T), and background (B). The P/B, P/T, and T/B ratios were calculated. The T/B ratio was relatively constant (range, 1.5-1.8; mean, 1.6), while a wide variability was observed both for P/T ratio (range, 1.2-2.3; mean, 1.7) and P/B ratio (range, 2.1-4.0; mean, 2.9). At surgery single enlarged parathyroid glands were easily identified by means of intraoperative MIBI-guided gamma probe. Moreover, the gamma probe allowed us to perform a limited 2-2.5 cm neck incision in eight patients affected by parathyroid adenoma. In the remaining patient a parathyroid carcinoma was diagnosed and a bilateral neck exploration was performed. The intraoperative MIBI gamma probe seems to be a useful aid when limited invasive parathyroid surgery is performed.