ESR Essentials: imaging of middle ear cholesteatoma-practice recommendations by the European Society of Head and Neck Radiology.

Although non-malignant, middle ear cholesteatoma can result in significant complications due to local bone erosion and infection. The treatment of cholesteatoma is surgical, but residual disease is common and may be clinically occult, particularly when the canal wall is preserved or reconstructive techniques are employed. Imaging plays a pivotal role in the management of patients with middle ear cholesteatoma-aiding clinical diagnosis, identifying complications, planning surgery, and detecting residual disease at follow-up. Computed tomography is the primary imaging tool in the preoperative setting since it can provide both a surgical roadmap and detect erosive complications of cholesteatoma. The ability of magnetic resonance imaging with non-echoplanar diffusion-weighted sequences to accurately detect residual disease has led to a shift in the diagnostic paradigm for post-surgical follow-up of cholesteatoma, such that routine "second-look" surgery is no longer required. The following practice recommendations are aimed at helping the radiologist choose appropriate imaging approaches and understand the key diagnostic considerations for the evaluation of pre- and post-surgical middle ear cholesteatoma. KEY POINTS: In the preoperative setting, CT is the first-line imaging modality and MRI is reserved for rare clinical scenarios (low evidence). Non-echoplanar imaging (EPI) DWI is the optimal MRI sequence for the detection of residual cholesteatoma (moderate evidence). Non-EPI DWI plays an important role in the postoperative surveillance of cholesteatoma (moderate evidence).

Magnetic resonance imaging evaluation of cochlear and vestibular nerve calibre: a case-control study in Ménière's disease and endolymphatic hydrops.

PURPOSE: To compare the calibre of the cochlear (CN), superior vestibular (SVN) and inferior vestibular (IVN) nerves on magnetic resonance imaging (MRI), both between Ménière's Disease (MD) ears and clinical controls, and between inner ears with and without endolymphatic hydrops (EH) on MRI. METHODS: A retrospective case-control study evaluated patients undergoing MRI for suspected hydropic ear disease from 9/2017 to 8/2022. The CN, SVN, IVN and facial nerve (FN) diameters and cross-sectional areas (CSA) were measured on T2-weighted sequences whilst EH was evaluated on delayed post-gadolinium MRI. Absolute nerve calibre (and that relative to the FN) in unilateral definite MD ears (2015 Barany criteria) was compared to that in both asymptomatic contralateral ears and clinical control ears. Nerve calibre in ears with severe cochlear and vestibular EH was compared to ears without EH. t tests or Wilcoxon signed-rank test/Mann-Whitney U test were applied (p < 0.001). RESULTS: 173 patients (mean age 51.3 ± 15.1, 65 men) with 84 MD (62 unilateral) and 62 clinical control ears were studied. Absolute and relative CN dimensions were decreased in both MD ears (CSA and diameter) and the contralateral asymptomatic ears (CSA) when compared to clinical controls (p < 0.001). Absolute nerve dimensions were reduced in both severe vestibular EH (CN, IVN and SVN) and severe cochlear EH (CN) (p < 0.001), however this was not evident when adjusted according to facial nerve calibre. CONCLUSION: There is decreased absolute CN calibre in both symptomatic and asymptomatic MD ears as well as ears with severe cochlear and vestibular EH on MRI.

Assessing the optimal MRI descriptors to diagnose Ménière's disease and the added value of analysing the vestibular aqueduct.

OBJECTIVES: To evaluate the diagnostic performance and reliability of MRI descriptors used for the detection of Ménière's disease (MD) on delayed post-gadolinium MRI. To determine which combination of descriptors should be optimally applied and whether analysis of the vestibular aqueduct (VA) contributes to the diagnosis. MATERIALS AND METHODS: This retrospective single centre case-control study evaluated delayed post-gadolinium MRI of patients with Ménièriform symptoms examined consecutively between Dec 2017 and March 2023. Two observers evaluated 17 MRI descriptors of MD and quantified perilymphatic enhancement (PLE) in the cochlea. Definite MD ears according to the 2015 Barany Society criteria were compared to control ears. Cohen's kappa and diagnostic odds ratio (DORs) were calculated for each descriptor. Forward stepwise logistic regression determined which combination of MRI descriptors would best predict MD ears, and the area under the receiver operating characteristic curve for this model was measured. RESULTS: A total of 227 patients (mean age 48.3 ± 14.6, 99 men) with 96 definite MD and 78 control ears were evaluated. The presence of saccular abnormality (absent, as large as or confluent with the utricle) performed best with a DOR of 292.6 (95% confidence interval (CI), 38.305-2235.058). All VA descriptors demonstrated excellent reliability and with DORs of 7.761 (95% CI, 3.517-17.125) to 18.1 (95% CI, 8.445-39.170). Combining these saccular abnormalities with asymmetric cochlear PLE and an incompletely visualised VA correctly classified 90.2% of cases (sensitivity 84.4%, specificity 97.4%, AUC 0.938). CONCLUSION: Either absent, enlarged or confluent saccules are the best predictors of MD. Incomplete visualisation of the VA adds value to the diagnosis. CLINICAL RELEVANCE STATEMENT: A number of different MRI descriptors have been proposed for the diagnosis of Ménière's disease, but by establishing the optimally performing MRI features and highlighting new useful descriptors, there is an opportunity to improve the diagnostic performance of Ménière's disease imaging. KEY POINTS: • A comprehensive range of existing and novel vestibular aqueduct delayed post-gadolinium MRI descriptors were compared for their diagnostic performance in Ménière's disease. • Saccular abnormality (absent, confluent with or larger than the utricle) is a reliable descriptor and is the optimal individual MRI predictor of Ménière's disease. • The presence of this saccule descriptor or asymmetric perilymphatic enhancement and incomplete vestibular aqueduct visualisation will optimise the MRI diagnosis of Ménière's disease.

Updates in head and neck cytopathology: Insights from European Congress of Pathology Short Course.

Cytological specimens play a pivotal role in head and neck nodule/mass work up and diagnoses. The specimens´ importance has grown with the onset of personalized medicine and the routine use of molecular markers in the diagnostic work up. The Updates in Head and Neck Cytopathology Short Course ran during the 35th European Congress of Pathology held in Dublin, Ireland, in 2023 and brought together experts in cytopathology, pathology, and related fields to share their expertise and experience in the field of head and neck cytopathology and its future directions. Topics such as a one-stop clinic, the Milan System for Reporting Salivary Gland Cytopathology, next generation sequencing, and human papilloma virus detection in the head and neck area were covered during the short course. These topics are briefly summarized in the present review.

Water soluble swallow for leak detection after total laryngectomy post radiotherapy.

AIM: Pharyngeal leak (PL) and pharyngocutaneous fistula (PCF) are serious complications following total laryngectomy and their incidence is higher in the salvage setting. The aim of this study is to describe the accuracy of water soluble swallow (WSS) to rule out salivary postoperative leak after salvage total laryngectomy (STL) to expedite start of oral intake. MATERIAL AND METHODS: Retrospective study including patients undergoing STL between 2008 and 2021 at Guy's Hospital. WSS was routinely performed within 15 days post operation. RESULTS: Sixty-six patients underwent STL. Nine developed clinically diagnosed PCF; one died before having WSS. Fifty-six patients underwent WSS post STL. WSS was performed within 15 days after STL when no postoperative complications occurred (76.8%). Among patients undergoing WSS with no clinical suspicion for fistula (56), PL was identified in 15 cases (26.8%). They were managed conservatively; PCF was avoided in 7(46.7%) cases. Three patients (7.3%) developed PCF after having started oral intake with a negative WSS. These three cases were further analysed, 2 cases where recorded at the beginning of the studied period when less experience was available possibly leading to incorrect results. Sensitivity and negative predictive value (NPV) for fistula prediction were 72.7% and 92.7%, respectively. CONCLUSION: Taking into account the high NPV of WSS, it is safe to start oral intake after negative WSS. Further studies to evaluate its accuracy earlier on after SLT are justified taking into account the results and the impact that delayed feeding has on patient's quality of life.

Consensus statement on the management of incidentally discovered FDG avid thyroid nodules in patients being investigated for other cancers.

With the widespread use of 18F-fluorodeoxyglucose positron emission tomography (FDG PET/CT) in the investigation and staging of cancers, incidental discovery of FDG-avid thyroid nodules is becoming increasingly common, with a reported incidence in the range 1%-4% of FDG PET/CT scans. The risk of malignancy in an incidentally discovered FDG avid thyroid nodule is not clear due to selection bias in reported retrospective series but is likely to be less than 15%. Even in cases where the nodule is found to be malignant, the majority will be differentiated thyroid cancers with an excellent prognosis even without treatment. If, due to index cancer diagnosis, age and co-morbidities, it is unlikely that the patient will survive 5 years, further investigation of an incidental FDG avid thyroid nodule is unlikely to be warranted. We provide a consensus statement on the circumstances in which further investigation of FDG avid thyroid nodules with ultrasound and fine needle aspiration might be appropriate.

Imaging of human papilloma virus associated oropharyngeal squamous cell carcinoma and its impact on diagnosis, prognostication, and response assessment.

The clinical behaviour and outcomes of patients with oropharyngeal cancer (OPC) may be dichotomised according to their association with human papilloma virus (HPV) infection. Patients with HPV-associated disease (HPV+OPC) have a distinct demographic profile, clinical phenotype and demonstrate considerably better responses to chemoradiotherapy. This has led to a reappraisal of staging and treatment strategies for HPV+OPC, which are underpinned by radiological data. Structural modalities, such as CT and MRI can provide accurate staging information. These can be combined with ultrasound-guided tissue sampling and functional techniques (such as diffusion-weighted MRI and 18F-fludeoxyglucose positron emission tomography-CT) to monitor response to treatment, derive prognostic information, and to identify individuals who might benefit from intensification or deintensification strategies. Furthermore, advanced MRI techniques, such as intravoxel incoherent motion and perfusion MRI as well as application of artificial intelligence and radiomic techniques, have shown promise in treatment response monitoring and prognostication. The following review will consider the contemporary role and knowledge on imaging in HPV+OPC.

Tumour detection and outcomes of surveillance screening in SDHB and SDHD pathogenic variant carriers.

OBJECTIVE: Succinate dehydrogenase subunit (SDHx) pathogenic variants predispose to phaeochromocytoma and paraganglioma (PPGL). Lifelong surveillance is recommended for all patients to enable prompt detection and treatment. There is currently limited evidence for optimal surveillance strategies in hereditary PPGL. We aim to detail the clinical presentation of PPGL in our cohort of non-index SDHB and SDHD pathogenic variant carriers. METHODS: Retrospective analysis of medical and genetic records from a single tertiary referral centre identified SDHB or SDHD pathogenic variants in 74 non-index cases (56 SDHB and 18 SDHD). Surveillance screening for asymptomatic relatives consisted of annual plasma metanephrine measurement and whole-body MRI with contrast at 3-5 yearly intervals. RESULTS: Twenty-three out of 74 non-index patients (10 SDHB and 13 SDHD) were diagnosed with PPGL, 17 patients through surveillance screening (24 tumours in total) and 6 diagnosed prior to commencement of cascade screening with symptomatic presentation. MRI with contrast identified PPGL in 22/24 screen-detected tumours and 5/24 tumours had elevated plasma metanephrine levels. Penetrance in non-index family members was 15.2 and 47.2% for SDHB carriers and 71.6 and 78.7% for SDHD carriers at age of 50 and 70 years, respectively. CONCLUSION: Surveillance screening with combined biochemical testing and imaging enables early detection of PPGL in asymptomatic relatives with SDHx pathogenic variants. The presence of disease at first screen was significant in our cohort and hence further multi-centre long-term data are needed to inform counselling of family members undergoing lifelong surveillance.

New and Advanced Magnetic Resonance Imaging Diagnostic Imaging Techniques in the Evaluation of Cranial Nerves and the Skull Base.

The skull base and cranial nerves are technically challenging to evaluate using magnetic resonance (MR) imaging, owing to a combination of anatomic complexity and artifacts. However, improvements in hardware, software and sequence development seek to address these challenges. This section will discuss cranial nerve imaging, with particular attention to the techniques, applications and limitations of MR neurography, diffusion tensor imaging and tractography. Advanced MR imaging techniques for skull base pathology will also be discussed, including diffusion-weighted imaging, perfusion and permeability imaging, with a particular focus on practical applications.

A Rare Case of Orbital Cellulitis with Progressive Calvarial Osteomyelitis.

Orbital cellulitis is a potentially sight and life-threatening complication of acute sinusitis, and the association with osteomyelitis is rare in the era of antibiotic-use. A 13-year-old girl presented with coryzal symptoms and severe headache, with a CT head being consistent with a diagnosis of pansinusitis and orbital cellulitis with abscess formation. She proceeded to have surgical drainage through a combined endoscopic and external approach to intraorbital abscess drainage with frontal trephine. She was also diagnosed with progressive calvarial osteomyelitis involving the right frontal bone, treated with a prolonged course of intravenous antibiotics. Our case highlights the importance of a high index of suspicion for complications of sinusitis. Multimodal imaging is essential to establish the extent of infection, and a multi-disciplinary approach is integral to manage this rare complication.

Computed tomographic features of the proximal petrous facial nerve canal in recurrent Bell's palsy.

OBJECTIVES: The primary objective was to determine whether the narrowest dimensions of the labyrinthine facial nerve (LFN) canal on the symptomatic side in patients with unilateral recurrent Bell's palsy (BP) differ from those on the contralateral side or in asymptomatic, age- and gender-matched controls on computed tomography (CT). The secondary objectives were to assess the extent of bony covering at the geniculate ganglion and to record inter-observer reliability of the CT measurements. METHODS: The dimensions of the LFN canal at its narrowest point perpendicular to the long axis and the extent of bony covering at the geniculate ganglion were assessed by two radiologists. Statistical analysis was performed using the Wilcoxon signed-rank and Mann-Whitney U tests (LFN canal dimensions) and the Chi-squared test (bony covering at the geniculate ganglion). Inter-observer reliability was evaluated using Intra-Class Correlation (ICC) and Cohen's kappa. RESULTS: The study included 21 patients with unilateral recurrent BP and 21 asymptomatic controls. There was no significant difference in the narrowest dimensions of the ipsilateral LFN canal when compared to the contralateral side or controls (P = .43-.94). Similarly, there was no significant difference in the extent of bony covering at the geniculate ganglion when compared to either group (P = .19-.8). Good inter-observer reliability was observed for LFN measurements (ICC = 0.75-0.88) but not for the bony covering at the geniculate ganglion (Cohen's kappa = 0.53). CONCLUSION: The narrowest dimensions of the LFN canal and the extent of bony covering at the geniculate ganglion do not differ in unilateral recurrent BP, casting doubt over their etiological significance. LEVEL OF EVIDENCE: Level IV.

Case report of a man with multiple paragangliomas and pathogenic germline variants in both NF1 and SDHD.

We report a novel case of multiple paragangliomas in a patient who was identified with pathogenic variants in both NF1 and SDHD genes. The proband is a man with known familial NF1 disease, diagnosed clinically in childhood. Multiple head and neck paragangliomas (HNPGL) were found during investigations for acute left sided neurological symptoms, in the region of his known plexiform neurofibroma. He was referred for genetic counselling. He underwent surgery to remove a left carotid body tumor (CBT). A pheochromocytoma and paraganglioma gene panel was tested. Blood and HNPGL tumor DNA were analyzed by whole exome sequencing. In addition to the NF1 truncating variant c.5107delA, p.(Ser1703AlafsTer7), the SDHD truncating pathogenic variant c.3G > A, p.(Met1?) was found. Tumor sequencing showed no LOH of SDHD or NF1, but monoallelic loss of 11p15 and 11q12.2-q12.3 was observed. Co-occurrence of pathogenic variants in multiple cancer susceptibility genes is rare but possible, identified by the increased use of panel testing. This is the first description of a patient presenting with NF1 and SDHD dual pathology, with HNPGL development due to SDHD. This case illustrates the central role of genetic sequencing in PPGLs and the strong genotype-phenotype correlations of different genes.

Utilization of SEMAC-VAT MRI for Improved Visualization of Posterior Fossa Structures in Patients With Cochlear Implants.

OBJECTIVE: The number of cochlear implant (CI) users is ever increasing worldwide, as is the utilization of magnetic resonance imaging (MRI) as a key diagnostic modality for pathology of the brain and surrounding structures. Despite advances in MRI compatibility with CI, metal artefact remains a significant issue that needs to be addressed. We test our hypothesis that the slice encoding for metal artefact correction and view angle tilting (SEMAC-VAT) metal artefact reduction technique improves demonstration of posterior fossa structures on MRI in CI recipients. STUDY DESIGN: A retrospective case review. SETTING: A tertiary referral hearing implant and skull base center. INTERVENTIONS: Dedicated MRI of the posterior fossa using T1 spin echo post-gadolinium sequences with and without the application of SEMAC-VAT in CI recipients. MAIN OUTCOME MEASURES: Extent and severity of the artefact and visualization of surrounding anatomic structures with and without the application of SEMAC-VAT, allowing for direct comparison. RESULTS: Eight CI recipients with nine CI devices were analyzed. We noted a significant reduction in signal void and improved visibility of the ipsilateral hemisphere in every case. Penumbra size increased although there was improved visibility through the penumbra. There was improved visualization of key intracranial structures, such as the ipsilateral internal auditory canal, cerebellopontine angle, cerebellar hemisphere, and brainstem. CONCLUSIONS: Application of SEMAC-VAT produces a significant reduction in signal void and improved visualization of key structures within the temporal bone and posterior cranial fossa in patients with CIs without the need for removal of the internal magnet.

Imaging in trauma of the facial skeleton and soft tissues of the neck.

Trauma to the face and neck is a frequent reason for emergency department attendance. Imaging is invaluable in the characterisation of such injuries, enabling delineation of fracture patterns as well as identification of vascular and other soft tissue injuries. It may also be used to prevent long-term mortality and morbidity and provide a roadmap for surgical intervention so that form and function may be restored. This article gives a pictorial review of the imaging of craniofacial trauma, stratified according to the thirds of the face, followed by a review of blunt and penetrating trauma of the neck. It discusses appropriate imaging modalities for each trauma category, describes major patterns of craniofacial trauma on cross-sectional imaging and identifies clinically relevant imaging features that should trigger subspecialist review or be of relevance to pre-surgical planning. It starts with the upper third comprising frontal sinus fractures before describing the component fractures of the middle third (including nasal, zygomaticomaxillary and orbital fractures) and then focusing on the lower third (specifically mandibular and dentoalveolar fractures). The article concludes with a review of soft tissue injuries of the neck, particularly penetrating, blunt and laryngeal trauma.

Imaging Soft-tissue Sarcomas of the Head and Neck: A Tertiary Soft-tissue Sarcoma Unit Experience.

BACKGROUND/AIM: To describe imaging features of head and neck soft-tissue sarcomas. PATIENTS AND METHODS: Patients with a diagnosis of head and neck sarcoma between 2011 and 2015 were reviewed. RESULTS: There were a total of 62 patients (24 female; median age=60 years). Most common sarcomas were angiosarcoma, undifferentiated pleomorphic sarcoma and sarcoma not otherwise specified. They were most commonly located in cranial and neck superficial soft tissues. Average tumour size at presentation was 45 mm. One patient had metastasis at presentation (rhabdomyosarcoma); two had nodal disease (rhabdomyosarcoma and angiosarcoma) and two tumours contained calcification (chondrosarcoma and synovial sarcoma). Four arose after prior radiotherapy. CONCLUSION: Unlike the more common diagnosis of squamous cell carcinoma, the majority of head and neck sarcomas present as large, solitary, superficial masses without lymph node enlargement. Identification of these features on imaging should raise suspicion of a sarcoma diagnosis, particularly in the setting of previous irradiation or genetic susceptibility.

Recent advances in MRI of the head and neck, skull base and cranial nerves: new and evolving sequences, analyses and clinical applications.

MRI is an invaluable diagnostic tool in the investigation and management of patients with pathology of the head and neck. However, numerous technical challenges exist, owing to a combination of fine anatomical detail, complex geometry (that is subject to frequent motion) and susceptibility effects from both endogenous structures and exogenous implants. Over recent years, there have been rapid developments in several aspects of head and neck imaging including higher resolution, isotropic 3D sequences, diffusion-weighted and diffusion-tensor imaging as well as permeability and perfusion imaging. These have led to improvements in anatomic, dynamic and functional imaging. Further developments using contrast-enhanced 3D FLAIR for the delineation of endolymphatic structures and black bone imaging for osseous structures are opening new diagnostic avenues. Furthermore, technical advances in compressed sensing and metal artefact reduction have the capacity to improve imaging speed and quality, respectively. This review explores novel and evolving MRI sequences that can be employed to evaluate diseases of the head and neck, including the skull base.

MRI findings in vestibular paroxysmia - An observational study.

BACKGROUND/OBJECTIVES: Vestibular paroxysmia (VP) presents as episodic vertigo believed to be caused by neurovascular cross-compression (NVCC) of the vestibulocochlear nerve. We investigated whether NVCC occurred at a higher rate in VP, compared with controls and whether angulation of the nerve, the vessel involved and location of the point of contact were significant features. METHODS: Retrospective analysis was conducted of MR imaging performed in patients with VP and also patients with unilateral tinnitus (in whom the asymptomatic side was used as a control). Two independent, blinded reviewers assessed each case. RESULTS: Nine patients with VP and 20 patients with unilateral tinnitus were included. NVCC was demonstrated in all 9 VP patients (100%), compared with 9 of the controls (45%), p = 0.0049. NVCC was mostly caused by a branch of the anterior inferior cerebellar artery (AICA). Nerve angulation at the point of contact occurred in 5 of the cases (44%), but in none of the controls (specificity = 100%), p = 0.0053. There was no correlation between site of contact and VP. CONCLUSION: Our study supports the concept of NVCC in VP and additionally suggests that nerve angulation may be a specific feature. Neurovascular contact remains a common phenomenon in asymptomatic patients and therefore correlation with neuro-otology assessment remains essential.

Skull base ligamentous mineralisation: evaluation using computed tomography and a review of the clinical relevance.

OBJECTIVES: To determine the frequency, morphologic and demographic characteristics, and clinical relevance of the mineralisation of six skull base ligaments (interclinoid, caroticoclinoid, petrosphenoid, posterior petroclinoid, pterygospinous, and pterygoalar). METHODS: This is a retrospective review of 240 CT scans of the paranasal sinuses (ages 6-80 years). A limited systematic review was performed primarily using Embase and Medline databases. RESULTS: Ligamentous mineralisation was well delineated on CT and occurred at ≥ 1 location in 58.3% of patients. There was a nonsignificant trend towards a greater incidence with advancing age. The interclinoid and posterior petroclinoid ligaments were most commonly mineralised (22.1% and 18.3%, respectively); the petrosphenoid and pterygoalar ligaments were least frequently mineralised (10.8% and 6.3%, respectively). The mean age of patients with posterior petroclinoid mineralisation was significantly greater than those with interclinoid and petrosphenoid mineralisation and was not seen in patients aged 6-20 years. The literature review highlighted the clinically relevant potential for mineralised ligaments to cause barriers to surgical access (e.g. to the foramen ovale), increase the risk of neurovascular injury during surgery at the skull base (e.g. during anterior clinoidectomy), and predispose to neural impingement. CONCLUSIONS: Skull base ligamentous mineralisation is commonly encountered on CT imaging. Given the potentially significant clinical implications, an understanding of the morphological appearances is of importance to those planning interventions at the skull base. To the authors' knowledge, this study is the first to comprehensively evaluate such a wide range of skull base ligaments using CT. For some ligaments, the incidence on CT has not been previously described.

Temporal Bone Tumors: An Imaging Update.

In their variety, temporal bone tumors mirror the complexity of the structure from which they arise. They include more familiar lesions, such as vestibular schwannomas and paragangliomas, and also rarer neoplasms, such as nonvestibular schwannomas, sarcomas, giant cell tumors, Schneiderian papillomas, and endolymphatic sac tumors. Diagnostic imaging is invaluable in evaluating such lesions because they are typically challenging to access surgically and monitor clinically. The ability to differentiate tumors from benign ('don't touch') or indolent lesions can prevent unnecessary morbidity. This article reviews a range of temporal bone neoplasms, focusing on imaging approaches and characteristic imaging findings.

SPECT/CT-Guided Ultrasound for Parathyroid Adenoma Localization: A 1-Stop Approach.

Our rationale was to evaluate the accuracy of 1-stop (single patient-attendance) SPECT/CT-guided ultrasound in the localization of parathyroid adenomata. Secondary aims included analyzing the effect of multiple parathyroid adenomata and concurrent thyroid disease on sensitivity. Methods: Patients with hyperparathyroidism who had undergone parathyroidectomy were identified over a 5-y period. Pathologic correlation with results from preoperative 99mTc-sestamibi SPECT/CT followed by targeted ultrasound of the neck was performed. The number of glands, the location, and the presence of concurrent thyroid disease were reviewed. Results: The study included 146 patients (88% single gland, 7% multigland, and 5% negative explorations). The sensitivity and specificity of SPECT/CT-guided ultrasound were 83% and 96%, respectively. The sensitivity was higher for single gland (87%) than multigland disease (70%). The addition of ultrasound significantly increased the sensitivity of the technique (P < 0.001). The presence of concurrent thyroid disease (nodules/thyroiditis) did not adversely affect sensitivity (85% confidence interval, 74.2%-93.1%) compared with normal or atrophic glands (82% confidence interval, 72.3%-89.7%). Conclusion: SPECT/CT-guided ultrasound represents a useful means of localizing parathyroid adenomata, thereby aiding the decision to undertake minimally invasive or exploratory surgery. The 1-stop approach offers patient convenience and enables the radiologist to use the additive benefits of both modalities to optimize localization. The technique is less sensitive in multigland disease, but concurrent thyroid disease does not adversely affect sensitivity.