头颈少见部位副神经节瘤

目的提高对头颈部罕见部位副神经节瘤的认识和诊断水平。方法搜集1990年1月至2003年12月经手术病理证实的6例头颈部罕见部位副神经节瘤，详细分析其临床和影像学表现。结果2例位于颈静脉窝，其中1例侵入鼓室；1例突入后颅窝；1例局限于鼓室；1例发生于左C1～C2椎体后部，肿瘤破坏椎板骨质，侵入椎管和后颅窝，浸润硬膜；1例位于颏下口底；1例位于眶内肌锥外。B超、CT和MRI显示肿瘤为实性，肿瘤内及其周围血管增多，强化明显，MR血管成像(MRA)和DSA均显示肿瘤染色和丰富的供血动脉。结论这些肿瘤虽然发生的部位不典型，但是具有共同的影像学特点，结合临床术前多可以诊断。     

Imaging and management of head and neck paragangliomas

Paragangliomas of the head and neck are highly vascular lesions originating from paraganglionic tissue located at the carotid bifurcation (carotid body tumors), along the vagus nerve (vagal paragangliomas), and in the jugular fossa and tympanic cavity (jugulotympanic paragangliomas). Diagnostic imaging can be considered in two clinical situations: (1) patients who present with clinical symptoms suggestive of a paraganglioma, and (2) individuals from families with hereditary paragangliomas. It is not only necessary to detect and characterize the lesion, but also to study the presence of multiplicity. For these purposes, MR imaging, and especially 3D TOF MRA, is the modality of choice. CT scanning is especially useful to show destruction of the temporal bone. Angiography in combination with embolization will mainly be used prior to surgical resection, but can also be used for diagnostic purposes when the diagnosis is not yet clear. Many parameters play a role in the decision to treat of which multifocality and impairment of cranial nerves are the most important. The primary therapeutic option for paragangliomas is complete excision of tumor with preservation of vital neurovascular structures. Resection however, should be balanced against a more conservative wait and scan policy or palliative treatments such as radiotherapy.     

High-resolution computed tomography of paragangliomas of the head and neck

High-resolution computed tomography with intravenous contrast enhancement is the initial procedure performed on individuals who present with signs and symptoms of a paraganglioma of the head and neck. Clinical information about these entities is reviewed and technical considerations are discussed.     

Death from pulmonary embolism of cyanoacrylate glue following gastric varix endoscopic injection

We present the case of a 25 year old woman with a complex past medical history including Crigler-Najjar syndrome (Type 1) with a liver transplant in 1993 and subsequent development of cirrhosis with portal hypertension in the transplanted liver. The deceased presented to hospital with hematemesis and investigations showed a large gastric varix. The varix was injected with cyanoacrylate glue. Within 30 min of injection the patient became acutely hypoxic. Urgent chest X-ray demonstrated radio opaque glue within the pulmonary arteries. It was evident that future treatment was futile and supportive treatment was withdrawn. The deceased was referred for medico legal post mortem examination. The post mortem CT scan performed prior to autopsy showed widespread radio-opaque material within the pulmonary arteries. At autopsy, rubbery grey/tan “clot” occluded the major proximal and segmental pulmonary arteries. Microscopic examination of the “clot” showed clumps of erythrocytes surrounded by foreign material. We discuss this relatively uncommon but well recognized complication of variceal injection with cyanoacrylate glue.     

Irradiated paragangliomas of the head and neck: CT and MR appearance.

PURPOSETo present the spectrum of CT and MR findings of glomus tumors of the head and neck successfully treated with radiation therapy.METHODSThe patient charts and all CT and MR studies of 24 patients (25 tumors) who had been successfully treated with radiation therapy were retrospectively reviewed. Eighteen patients had pre- and posttreatment imaging studies. Tumor size, internal morphology, enhancement pattern, visualization of flow voids, and bone erosion were evaluated before and after radiation therapy. Statistical evaluation of the presence of flows voids and tumor size was performed using the Fischer Exact Test.RESULTSAll patients had residual tumor after radiation therapy. Sixty-one percent of tumors demonstrated a reduction in size. Only one tumor with pretreatment bone destruction demonstrated healing of the bone. MR findings after radiation therapy included variable alteration in T2 signal, decreased heterogeneous enhancement, and a reduction in flow voids. There was a significant difference in the presence of flow voids based on tumor size.CONCLUSIONSSuccessfully irradiated paragangliomas demonstrate residual masses, the presence of which does not by itself indicate treatment failure. Stabilization or reduction in size, decreased enhancement, diminished flow voids, and reduced T2 signal after radiation therapy are a result of therapy and are indicative of local control. Persistent bone demineralization and erosion without progression is commonly seen in successfully controlled tumors. Paragangliomas are relatively homogeneous in internal morphology except for areas of flow void. Flow voids are not a reliable criterion for diagnosis in lesions less than 2.5 cm.     

The value of MR angiography techniques in the detection of head and neck paragangliomas

OBJECTIVE: The objective of this study was to compare three-dimensional phase-contrast angiography (3D PCA), 2D time-of-flight (2D TOF), and 3D TOF magnetic resonance (MR) angiography and a proton density weighted technique in terms of their ability to detect head and neck paragangliomas. MATERIALS AND METHODS: 14 patients with 29 paragangliomas were examined at 1.5 T. Three MR angiography sequences (3D PCA, 2D TOF, and multi-slab 3D TOF) and a proton density (PD) weighted sequence were reviewed by four neuroradiologists. The gold standard was digital subtraction angiography. Presence of tumor was assessed in five grades of confidence. Sensitivity and specificity were calculated after dichotomizing the results. Data was analyzed using the logistic regression method. RESULTS: Mean sensitivity and specificity for the four observers were for PD: 72%/97%, for 3D PCA: 75%/90%, for 2D TOF: 66%/93%, and for 3D TOF: 90%/92%. Sensitivity was significantly better for 3D TOF MRA (P < 0.001). No substantial between-observer variation for tumor detection was present. CONCLUSION: Our results demonstrate that, using 3D TOF MRA, paragangliomas in the head and neck region can be detected with high sensitivity and specificity. Further investigation is necessary to judge the value of 3D TOF MR angiography against fat suppressed contrast enhanced T1 weighted and fat suppressed T2 weighted MR sequences to find the optimal imaging sequence for paragangliomas.     

Clinical value of somatostatin receptor imaging in patients with suspected head and neck paragangliomas

Paragangliomas or glomus tumours of the head and neck region are rare somatostatin receptor-expressing neuroendocrine tumours. Precise preoperative diagnosis is of special importance in order to adequately weigh the potential benefit of the operation against the inherent risks of the procedure. In this study, the clinical value of somatostatin receptor imaging was assessed in 19 patients who underwent somatostatin receptor scintigraphy because of known or suspected paraganglioma of the head and neck region. The results were compared with the results of computed tomography and/or magnetic resonance imaging, histology and clinical follow-up. [(111)In-DTPA- D-Phe(1)]-octreotide scintigraphy was performed 4-6 and 24 h after i.v. injection of 140-220 MBq (111)In-octreotide. Whole-body and planar images as well as single-photon emission tomography images were acquired and lesions were graded according to qualitative tracer uptake. Somatostatin receptor imaging was positive in nine patients, identifying paragangliomas for the first time in three patients and recurrent disease in six patients. In one patient, a second, previously unknown paraganglioma site was identified. Negative results were obtained in ten patients. These patients included one suffering from chronic hyperplastic otitis externa, one with granuloma tissue and an organised haematoma, one with an acoustic neuroma, one with an asymmetric internal carotid artery, two with ectasia of the bulbus venae jugularis and one with a jugular vein thrombosis. In two patients with a strong family history of paraganglioma, individual involvement could be excluded. In only one patient did somatostatin receptor imaging and magnetic resonance imaging yield false negative results in respect of recurrent paraganglioma tissue. It is concluded that somatostatin receptor scintigraphy provides important information in patients with suspected paragangliomas of the head and neck region and has a strong impact on further therapeutic management.     

Clinical impact of somatostatin receptor scintigraphy in the management of paragangliomas of the head and neck.

Paragangliomas are neuroendocrine tumors expressing somatostatinergic receptors and, thus, may be imaged by somatostatin receptor scintigraphy (SRS). The purpose of the study was to assess the contribution of SRS in the management of paraganglioma of the head and neck. METHODS: (111)In-Pentetreotide (148 MBq) was intravenously administered to 3 groups of patients. Group A consisted of 9 patients with tumors of the head and neck that did not exhibit typical radiologic features of paragangliomas and required further diagnostic evaluation. Group B consisted of 28 patients with known paragangliomas or paraganglioma metastatic lymph node who required staging and assessment of multicentricity. Group C consisted of 5 asymptomatic relatives of affected individuals who required screening. All patients underwent clinical, laboratory, radiologic, and audiovestibular evaluation. RESULTS: In group A (n = 9), SRS was positive in 6 cases, 4 paragangliomas and 2 meningiomas, and negative in 3 patients in whom the initial diagnosis of paraganglioma was excluded. In group B (n = 28), SRS was strongly positive in all of the 34 head and neck masses diagnosed on conventional imaging to be paragangliomas; it localized 1 primary malignant paraganglioma and revealed 9 unexpected foci. In group C (n = 5), SRS was positive in 3 of the 5 relatives, CT or MR scan confirming the diagnosis of paraganglioma in all cases. CONCLUSION: Because of very high sensitivity in detecting paraganglioma, SRS should be included in a multiple-step strategy for patients' management. It could be useful in ruling out the diagnosis of schwannoma, but its major advantage may involve patients' staging. Once biologic genetic testing of affected patients' relatives evidenced the predisposing mutation, SRS could be proposed to identify individuals who express the disease.     

111In-octreotide is superior to 123I-metaiodobenzylguanidine for scintigraphic detection of head and neck paragangliomas.

In this study, we evaluated the diagnostic yield of somatostatin receptor scintigraphy (SRS), I-metaiodobenzylguanidine (MIBG) scintigraphy, and morphologic imaging (CT or MRI) in patients with head and neck paragangliomas. METHODS: In a university hospital setting, patients considered to have head and neck paraganglioma were referred to the outpatient endocrinology department and underwent CT or MRI, SRS, and MIBG imaging. For validation, we used a composite reference standard consisting of clinical and histologic data and CT or MRI, with which SRS and MIBG imaging were compared. Urinary metanephrine and normetanephrine measurements were also obtained. RESULTS: Twenty-nine consecutively referred patients (17 women and 12 men) were included and were found to have paraganglioma. Both morphologic and SRS were positive in 27 patients (sensitivity, 93%, and 95% confidence interval [CI], 77%-98%, compared with the composite reference standard), whereas MIBG was positive in only 13 patients (44%; 95% CI, 23%-61%) (P < 0.001, compared with SRS). On a lesion-based analysis, morphologic imaging detected 31 lesions (sensitivity, 82%; 95% CI, 65%-92%), SRS detected 34 (89%; 95% CI, 75%-97%), and MIBG detected 15 (42%; 95% CI, 26%-59%). SRS was superior to MIBG (P = 0.001). With SRS, a previously unknown carcinoid tumor was detected in 1 patient, and a carcinoid was suspected in another patient. MIBG detected an additional adrenal pheochromocytoma in 1 patient. Urinary metanephrine or normetanephrine excretion was elevated in 6 patients. The number of lesions on SRS and MIBG per patient correlated with the levels of abnormal metanephrine or normetanephrine excretion (P = 0.005 and P = 0.02, respectively). CONCLUSION: SRS was superior to MIBG in patients with highly suspected head and neck paraganglioma.     

Bone metastases from head and neck paragangliomas: uncommon MR findings in an uncommon condition--report of three cases

Malignancy (defined as metastatic disease) has been reported in nearly 5% of head and neck paragangliomas. Metastases preferentially target the lymph nodes, lung, liver, or bone. We describe three patients with multiple silent bone metastases exhibiting a fatty halo at MRI that coexisted with expansive bone lesions. In all cases, (123)I-metaiodobenzylguanidine ((123)MIBG) scintigraphy showed no abnormal tracer uptake, whereas (111)In-pentetreotide scintigraphy visualized a few silent bone metastases. These findings indicate that MRI should be included in the staging of paraganglioma patients with risk factors for malignancy.     

Vascularization of head and neck paragangliomas: comparison of three MR angiographic techniques with digital subtraction angiography

BACKGROUND AND PURPOSE: MR angiography of the head and neck region has been studied widely, but few studies have been performed concerning the efficacy of MR angiography for the identification of the specific vascular supply of the highly vascular head and neck paragangliomas. In this study, we compared three MR angiography techniques with respect to visualization of branch arteries in the neck and identification of tumor feeders in patients with paragangliomas. METHODS: Fourteen patients with 29 paragangliomas were examined at 1.5 T using 3D phase-contrast (PC), 2D time-of-flight (2D TOF), and multi-slab 3D TOF MR angiography. In the first part of the study, two radiologists independently evaluated the visibility of first-, second-, and third-order branch arteries in the neck. In the second part of the study, the number of feeding arteries for every paraganglioma was determined and compared with digital subtraction angiography (DSA), the standard of reference in this study. RESULTS: Three-dimensional TOF angiography was superior to the other MR angiography techniques studied (P < .05) for depicting branch arteries of the external carotid artery in the neck, but only first- and second-order vessels were reliably shown. DSA showed a total of 78 feeding arteries in the group of patients with 29 paragangliomas, which was superior to what was revealed by all MR angiography techniques studied. More tumor feeders were identified with 3D TOF and 2D TOF angiography than with 3D PC MR angiography (P < .05), with a sensitivity/specificity of 61%/98%, 54%/95%, and 31%/95%, respectively. Sensitivity was lowest for carotid body tumors. CONCLUSION: Compared with intra-arterial DSA, the 3D TOF MR angiography technique was superior to 3D PC and 2D TOF MR angiography for identifying the first- and second-order vessels in the neck. With 3D TOF angiography, more tumor feeders were identified than with the other MR angiography techniques studied. The sensitivity of MR angiography, however, is not high enough to reveal important vascularization. The sensitivity of MR angiography is too low to replace DSA, especially in the presence of carotid body tumors.     

Dynamic contrast enhancement of paragangliomas of the head and neck: evaluation with time-resolved 2D MR projection angiography

Our objective was to evaluate tumor hemodynamics of paragangliomas of the head and neck. A 2D magnetic resonance projection angiography (MRPA) protocol was developed. Six patients with histologically proven paragangliomas were included in the study. The sequence protocol and data post-processing procedure were optimized in view of a high temporal resolution and maximum contrast-to-noise ratio. Image-time series of two freely orientated slabs could be obtained. Correlation analysis was performed to generate selective arterial and venous weighted angiographic images. Glomus tumors showed a rapid and intense homogeneous enhancement following the intravenous administration of contrast material. The smallest tumors investigated measured 10 mm and could be visualized clearly. Time-resolved analysis of the tumor enhancement revealed an early bolus arrival within the vascular bed of the tumor and prolonged incomplete washout indicating blood pooling. The dynamic contrast enhancement of glomus tumors can be evaluated non-invasively with MRPA providing a high temporal resolution and high image quality. The characteristic contrast enhancement of glomus tumors can be helpful in the diagnostic workup of lesions that may mimic glomus tumors.     

Improved distal distribution of n-butyl cyanoacrylate glue by simultaneous injection of dextrose 5% through the guiding catheter: technical note

Introduction The use of n-butyl cyanoacrylate (NBCA) as an adhesive agent for embolization of high-flow intracranial and extracranial vascular lesions is well established. To be successful, the embolization of arteriovenous malformations and fistulas must achieve obliteration of the arteriovenous shunts themselves rather than simply occlude the feeders proximal to the lesion. However, the feeders cannot always be negotiated over their entire length. This is often the case with dural arteriovenous fistulas (DAVF), which are usually vascularized by long and intricate meningeal networks. In such situations, NBCA may not be able to reach the lesion itself, rendering the embolization ineffective. We present a new technique that improves distal distribution of NBCA glue.Methods The technique described in this report consists of injecting dextrose 5% through the guiding catheter simultaneously with the superselective injection of NBCA glue into the targeted feeding branch. The technique is illustrated with three cases of posterior fossa DAVF.Results In the reported cases, flooding the territory of the targeted vessel with non-ionic dextrose 5% allowed deep progression of the glue by delaying contact with ionic substances. Excellent distribution of the NBCA glue reaching the site of the arteriovenous shunts was thus obtained despite suboptimal proximal microcatheter tip positions.Conclusion Simultaneous perfusion of dextrose 5% through the guiding catheter during NBCA injection dramatically improves the distal progression of glue through small, tortuous arterial feeders. This technique has the potential to increase the therapeutic value of transarterial embolization for DAVFs.     

Safety and technical efficacy of pre-operative embolization of head and neck paragangliomas: A 10-year mono-centric experience and systematic review

ObjectivesTo retrospectively evaluate the safety and technical success of pre-operative embolization (POE) of head and neck paragangliomas (HNP) in a single-center cohort over a 10-year period, and to benchmark our results with those derived from a systematic analysis of the available literature.MethodsAll consecutive HNP embolized between November 2010 and April 2020 were included and reviewed. In total, there were 27 HNP in 27 patients [8 (30%) males; 19 (70%) females; mean age 53 ± 16 years; range 30–86].Embolization technique, total procedure time, dose area product (DAP), complications, rate of HNP devascularization, and technical success (i.e. ≥80% devascularization of the HNP) were recorded and analyzed.A systematic analysis on the safety and technical success of POE was then conducted according to the Systematic Reviews and Meta-Analyses (PRISMA) guidelines.ResultsTwenty-one (21/27; 78%) HNP were treated with an endovascular approach and 6/27 (22%) with a percutaneous or combined (endovascular/percutaneous) technique. Mean total procedure time and DAP were 108 ± 48 min (range 45–235) and 92.5 ± 61.3 Gy·cm² (range 19.9–276.0), respectively. Two (2/27; 7%) complications (one minor, one major) were observed.Mean HNP devascularization was 88 ± 15% (range 23–100) with technical success achieved in 24/27 (89%) HNP.Literature analysis revealed a pooled rate of complication and technical success of 3.8% (95% CI: 0.5–8.8%) and 79.0% (95% CI: 63.6–91.6%), respectively.ConclusionsPOE of HNP is safe and results in extensive devascularization in the majority of treated tumors.     

Head and neck paragangliomas: value of contrast-enhanced 3D MR angiography

BACKGROUND AND PURPOSE: A rapid and accurate MR imaging technique would be beneficial to assess paragangliomas in the head and neck and to distinguish them from other lesions. The purpose of this study was to determine whether the combination of elliptic centric contrast-enhanced MR angiography (CE-MRA) and unenhanced and enhanced spin-echo imaging (conventional MR imaging) is more accurate than conventional MR imaging alone to assess paragangliomas in the head and neck.MATERIALS AND METHODS: Three radiologists retrospectively and independently reviewed CE-MRA and conventional MR imaging in 27 patients with suspected paragangliomas. The overall image quality and the probability of paraganglioma were recorded. The results of each technique and their combination were analyzed for sensitivity and specificity. Receiver operating characteristic (ROC) analyses were performed by using histologic analysis, imaging, and/or clinical findings as the reference standard.RESULTS: Forty-six lesions were found in 27 patients. In the assessment of paragangliomas, the combination of conventional MR imaging and CE-MRA was significantly superior to conventional MR imaging alone. Sensitivity and specificity respectively were the following: for CE-MRA, 100% and 94%; and for conventional MR imaging, 94% and 41%. The specificity of CE-MRA was significantly higher than that of conventional MR imaging (P = .004). There was good-to-excellent interobserver agreement for the paraganglioma probability with CE-MRA (nonweighted κ, 0.67–0.77), whereas there was fair-to-good interobserver agreement with conventional MR imaging (nonweighted κ, 0.50–0.65).CONCLUSION: In combination with conventional MR imaging, CE-MRA yields an excellent diagnostic value for the assessment of head and neck paragangliomas; hence, the 2 techniques should be regarded as complementary.

In the head and neck, paragangliomas are slow-growing hypervascular lesions that are most commonly located in 4 main sites: the carotid bifurcation, the foramen jugulare, the middle ear cavity, and along the cervical portion of the vagus nerve.¹ These lesions occur in both sporadic and hereditary forms (7% of cases). Multicentricity occurs in 10% of sporadic paragangliomas and in 30%–40% of familial paragangliomas.Imaging techniques are used for suspected head and neck paragangliomas to confirm this diagnosis.² Accurate assessment of tumor margins and invasion of adjacent structures are also essential for proper staging and therapy.³ For this task, MR imaging using unenhanced and enhanced fat-suppressed spin-echo (SE) sequences is widely accepted as the method of choice,^4,5 in addition to high-resolution CT,^6,7 in particular when the skull base is involved. Nonetheless, SE MR imaging has several limitations, particularly its sensitivity to artifacts.⁸ Moreover, the differentiation from other tumors and inflammatory lesions remains problematic. For example, the results of SE imaging are often equivocal when processes in the area of the jugular foramen are suspected.^9,10 Somatostatin receptor scintigraphy (SRS) may be useful in this situation but is not always conclusive. Digital subtraction angiography (DSA) is the current imaging reference standard for assessing the vascular architecture of the tumor before embolic therapy, but this method is invasive with a complication rate of 0.5%–1%,¹¹ which is too high for a diagnostic examination. Consequently, some investigators have discussed the utility of more specific methods in MR imaging to differentiate paragangliomas from other tumors or vascular abnormalities (dynamic MR imaging,¹² high-dose gadodiamide-injection dynamic MR imaging,¹³ or arterial and venous MR angiography [MRA]⁹).To our knowledge, the elliptical centric contrast-enhanced MRA (CE-MRA) sequence has not been assessed for visualizing paragangliomas and differentiating them from other lesions. We postulated that CE-MRA has the potential to simplify the interpretation of conventional MR imaging because intense tumor blush on CE-MRA may be a sensitive and specific feature for paragangliomas.The purpose of this study was to determine whether the combination of CE-MRA and conventional MR imaging is more accurate than conventional MR imaging alone to assess patients with suspected paragangliomas.