Metrizamide cisternography in the diagnosis of acoustic neurinomas

Summary Seventy-three cisternographies with metrizamide were performed on 69 patients, mainly for diagnosis of an acoustic neurinoma. Of the 31 patients with pathological findings on cisternography 26 underwent surgery for 23 acoustic neurinomas, one neurinoma of the facial nerve, and two meningiomas. For diagnosing small tumours of the cerebellopontine cistern, cisternography is superior to all other neuroradiological methods. Tomography of the porus acusticus internus and CT scanning are the initial radiological methods in patients with signs of cerebellopontine angle lesions; if no lesion is disclosed by these two methods cisternography with metrizamide should be performed to exclude a small tumour, particularly a small acoustic neurinoma.     

Unusual lesions of the cerebellopontine angle: a segmental approach.

Tumors of the cerebellopontine angle (CPA) are frequent; acoustic neuromas and meningiomas represent the great majority of such tumors. However, a large variety of unusual lesions can also be encountered in the CPA. The site of origin is the main factor in making a preoperative diagnosis for an unusual lesion of the CPA. In addition, it is essential to analyze attenuation at computed tomography (CT), signal intensity at magnetic resonance (MR) imaging, enhancement, shape and margins, extent, mass effect, and adjacent bone reaction. CPA masses can primarily arise from the cerebellopontine cistern and other CPA structures (arachnoid cyst, nonacoustic schwannoma, aneurysm, melanoma, miscellaneous meningeal lesions) or from embryologic remnants (epidermoid cyst, dermoid cyst, lipoma). Tumors can also invade the CPA by extension from the petrous bone or skull base (cholesterol granuloma, paraganglioma, chondromatous tumors, chordoma, endolymphatic sac tumor, pituitary adenoma, apex petrositis). Finally, CPA lesions can be secondary to an exophytic brainstem or ventricular tumor (glioma, choroid plexus papilloma, lymphoma, hemangioblastoma, ependymoma, medulloblastoma, dysembryoplastic neuroepithelial tumor). A close association between CT and MR imaging findings is very helpful in establishing the preoperative diagnosis for unusual lesions of the CPA.     

Computed tomography for small acoustic neuromas

Summary The minimal size of acoustic neuromas detectable by computed tomography (CT) is, according to the available literature, 1.5 to 2 cm. The new otoneurosurgical technic using the transtemporal and translabyrinthine approach necessitates an early diagnosis of neuromas protruding 1 cm or less into the cerebellopontine angle cistern. This seemed impossible with the available CT equipment. Eight proven acoustic neuromas 1 cm or less in diameter, detected with CT, are reported. Diagnostic criteria are elaborated. The study shows that small cerebellopontine angle tumors can be detected by use of CT machines of the newer generation which perform scanning with thin and overlapping slices.     

FDG PET/CT evaluation of pathologically proven pulmonary lesions in an area of high endemic granulomatous disease

Purpose

The goal of this study is to assess how reliable the threshold maximum standardized uptake value (maxSUV) of 2.5 on positron emission tomography–computed tomography (PET/CT) is for evaluation of solitary pulmonary lesions in an area of endemic granulomatous disease and to consider other imaging findings that may increase the accuracy of PET/CT.

Materials and methods

The staging PET/CT of 72 subjects with solitary pulmonary lesions (nodules (less than 3 cm) or masses (greater than 3 cm)) were retrospectively reviewed. Pathology proven diagnosis from tissue samples was used as the gold standard. Logistic regression was used to assess whether the subject’s age, maxSUV, size of lesion, presence of emphysema, or evidence of granulomatous disease was predictive of malignancy.

Results

Malignant lesions were identified in 84.7 % (61/72) of the 72 subjects. A threshold maxSUV of 2.5 had a sensitivity of 95.1 % (58/61), specificity of 45.5 % (5/11), positive predictive value of 90.6 % (58/64), negative predictive value of 62.5 % (5/8) and an accuracy of 87.5 % (63/72). The false negative rate was 4.9 %, and the false positive rate was 54.5 %. All 3 false negatives were less than or equal to 1.0 cm; however, false positives ranged from 1.1 to 5.6 cm. The false negatives had a mean (SD) maxSUV of 2.0 (0.4), whereas the false positives had a mean (SD) maxSUV of 5.6 (3.0). Emphysema was associated with 1.1 higher odds of malignancy, and evidence of granulomatous disease was associated with 0.34 lower odds of benign disease, however, neither was statistically significant (p = 0.92 and p = 0.31, respectively). Higher maxSUV was significantly associated with increased risk of malignancy (p = 8.3 × 10^?3). Older age and larger size of lesion were borderline associated with increased risk of malignancy (p = 0.05 and p = 0.07, respectively).

Conclusion

In an area of high endemic granulomatous disease, the PET/CT threshold maxSUV of 2.5 retains a high sensitivity (95.1 %) and positive predictive value (90.6 %) for differentiating benign from malignant pulmonary lesions; however, the specificity (45.5) and negative predictive value (62.5) decrease due to increased false positives. The presence of emphysema and absence of evidence of granulomatous disease increases the probability that a pulmonary lesion is malignant; however, these were not statistically significant.     

Imaging of cerebellopontine angle lesions: an update. Part 1: enhancing extra-axial lesions

Computed tomography (CT) and magnetic resonance (MR) imaging reliably demonstrate typical features of vestibular schwannomas or meningiomas in the vast majority of mass lesions in the cerebellopontine angle (CPA). However, a large variety of unusual lesions can also be encountered in the CPA. Covering the entire spectrum of lesions potentially found in the CPA, these articles explain the pertinent neuroimaging features that radiologists need to know to make clinically relevant diagnoses in these cases, including data from diffusion and perfusion-weighted imaging or MR spectroscopy, when available. A diagnostic algorithm based on the lesion’s site of origin, shape and margins, density, signal intensity and contrast material uptake is also proposed. Part 1 describes the different enhancing extra-axial CPA masses primarily arising from the cerebellopontine cistern and its contents, including vestibular and non-vestibular schwannomas, meningioma, metastasis, aneurysm, tuberculosis and other miscellaneous meningeal lesions.     

Epidermoid tumor of the cerebellopontine angle: signal loss in the contralateral cistern.

We report a case of an epidermoid tumor of the right cerebellopontine angle (CPA) in which the contralateral CPA cistern showed abnormal, low signal intensity on T2-weighted fast spin-echo MR images. Diffusion-weighted images showed the epidermoid tumor of the right CPA extending to the prepontine cistern. The cause of the abnormal signal intensity was proved to be an artifactual signal loss due to cerebrospinal fluid flow by phase-contrast MR imaging.     

Role of 11C-choline PET/CT in the restaging of prostate cancer patients showing a single lesion on bone scintigraphy

Aim

To assess the utility of ¹¹C-choline PET/CT in the restaging of prostate cancer (PC) patients who showed a single finding on bone scintigraphy (BS) that was classified as equivocal or suspected for metastatic lesion.

Materials and methods

A total of 25 PC patients with biochemical failure (mean PSA value 11.1 ng/mL; median value 6.3 ng/mL; range 0.2–37.7 ng/mL) after primary treatment were included in this retrospective study. All of them showed a single lesion on BS reported as suspected for metastatic lesion or as equivocal finding. Patients underwent ¹¹C-choline PET/CT within 1–4 months from BS. Validation was established by follow-up for at least 6 months.

Results

On the basis of biopsy confirmation and/or 6-month follow-up, 22 of 25 patients were classified as positive for the presence of metastatic bone lesions: 13 with a single lesion and 9 with multiple lesions. ¹¹C-choline PET/CT was positive in 19/25 patients and, on a lesion basis, it showed 50 positive findings. BS results were confirmed in 8/25 (32%) patients. ¹¹C-choline PET/CT detected multiple sites of relapse in 11/25 (44%) patients: in 2/11, a single bone lesion associated with other extraosseous sites of relapse; in 6/11, multiple bone lesions; in 3/11, multiple bone lesions and other extraosseous localizations. Finally, 6/25 patients were negative on ¹¹C-choline PET/CT. In 3/6 patients, an osteoblastic lesion was seen on CT attenuation correction images (PET false negative; BS true positive), while in 3/6 patients only findings suggestive of the presence of degenerative disease were found (PET true negative; BS false positive). On a patient basis, ¹¹C-choline PET/CT showed a diagnostic sensitivity of 86% (19/22) and a specificity of 100% (19/19).

Conclusions

In our study, ¹¹C-choline PET/CT detected unknown lesions in 11/25 patients. Patients with a single equivocal finding on BS could have important additional information from ¹¹C-choline PET/CT study, especially in the detection of additional metastases, to choose an appropriate treatment.     

面神经瘤的CT和MRI诊断(附六例报告)

目的 探讨CT,MRI对面神经瘤的诊断价值,方法 回顾分析了6例经手术病理证实的面神经瘤CT,MRI表现,结果 6例面神经瘤中位于颞内段4例（迷路段1例,鼓室段2例,鼓室段＋乳突段1例）,颅,内脑池段,内听段及颞内段（迷路段＋鼓室段）1例,颞内段（鼓室段＋乳突段＿并颅外肋腺段1例,肿瘤的影像学表现与肿瘤的部位有关,CT影像上,颞内段面神经瘤显示受累段面神经管扩大,破坏;中耳腔和（或）乳突软组织肿块及膝状神经窝区内质破坏,如肿瘤扩展到中颅窝或肋腺也可一并显示,1例起源于内听道,桥脑小脑角区的面神经瘤,CT,MRI清楚地显示了桥脑小脑角区肿块,内听道扩大,迷路段面神经管扩大,以及扩展到膝状神经窝区的病灶。结论 CT和MRI能准确地描绘面神经瘤的受累情况,CT在显示骨破坏细节方面极佳,而增强MRI对肿瘤本身的显示优于CT。     

Computed tomography of a cerebellopontine angle lipoma

In this report we document the clinical, radiologic, surgical, and pathologic features of a cerebellopontine angle (CPA) lipoma, including the CT visualization of the seventh and eighth cranial nerves passing through the middle of the lesion, a feature previously undescribed. Comparison is made with other reported CPA lipomas.     

18F-FDG PET与99Tcm-MDP骨扫描诊断肿瘤骨转移的比较分析

目的:探讨18F-FDG PET显像对于肿瘤骨转移的诊断价值,并与99Tcm-MDP骨显像进行对比分析。方法:97例肿瘤及疑诊为肿瘤的患者在30天内先后行18F-FDG PET-CT及99Tcm-MDP骨扫描,对比分析两者的显像结果。结果:97例中经临床和病理确诊基于病例分析,为骨转移63例,62例18F-FDG PET显像阳性,1例假阴性;99Tcm-MDP骨显像阳性49例,假阴性14例,两者敏感度分别为98.4%和77.8%,差异有显著性意义(P<0.05);34例为阴性患者,其中PET显像阴性29例、假阳性5例,骨显像阴性21例、假阳性13例,两者的特异度为85.3%和61.8%(P>0.05),符合率为93.8%和72.2%(P<0.05)。基于病灶分析,97例中共分析1261个骨骼区,骨转移存在于226个骨骼区,剔除不能定性的14个区,18F-FDG PET显像阳性222个区,假阴性4个区;而骨扫描显像阳性154个区,假阴性72个区;两者的敏感度分别为98.7%和68.1%,差异有显著性意义(P<0.05)。1021个阴性区,其中18F-FDGPET显像为阴性1010个区,假阳性11个区;骨扫描显像阴性1001个区,假阳性20个区;两者特异度分别为98.9%和98.0%,差异无统计学意义(P>0.05)。18F-FDG PET的诊断符合率为98.8%,骨显像为92.6%,两者差异有显著性意义(P<0.05)。以CT表现分组,溶骨性病灶和CT上无明显异常改变病灶的FDG PET和骨扫描的检出率分别为99.4%和72.6%及81.5%和40.7%,差异有显著性意义(P<0.05)。结论:18F-FDG PET诊断敏感度及准确性均高于骨扫描对溶骨病灶和CT上无明显改变病灶的检出优于骨扫描。     

The anatomical classification of AICA/PICA branching and configurations in the cerebellopontine angle area on 3D-drive thin slice T2WI MRI

BackgroundWith the technical advance of magnetic resonance imaging (MRI), we have been able to observe not only the small cranial nerves arising from the brain stem but also the branches of vertebrobasilar artery in the cerebellopontine angle (CPA) cistern.PurposeThe purpose was to demonstrate the courses and configurations of the anterior inferior cerebellar artery (AICA) or posterior inferior cerebellar artery (PICA) branch including the internal auditory artery in the CPA cistern and evaluate the relationship between the facial–vestibulocochlear (VIIth–VIIIth) nerves and AICA/PICA on high-resolution, thin-slice, three-dimensional T2-weighted MRI using driven equilibrium pulse.Material and methodsThirty-three men and 27 women aged 8–85 years old with sensory hearing loss or vertigo, and/or tinnitus were evaluated by thin-slice (0.75 mm) T2-weighted MRI. Five subjects (3 men, 2 women) without any auditory symptoms were also examined.ResultsThin-slice T2WI drive MRI revealed several variations of the AICA/PICA coursing, such as a loop formation (n=30, 48 sides) or the IAC extension (n=19, 30 sides). Contact with the vestibulocochlear nerve was seen in 31.7% subjects (n=19, 27 sides). The AICA/PICA branching and shape patterns relative to the CPA and IAC were classified into four major types: type 1A, nonloop AICA/PICA in the CPA cistern; type 1 B, nonloop AICA/PICA (internal auditory artery) entering the IAC; type 2A, loop-type AICA/PICA in the CPA cistern; and type 2B, loop-type AICA/PICA entering the IAC.ConclusionThere was statistically significant association between types 1A and 2A (P<.01) regarding the existence of any auditory 3 symptoms. The results of our study suggest that this classification is simple and very useful for the elucidation of the mechanism of auditory symptoms and deciding the therapeutic strategies.     

Bochdalek’s flower basket: applied neuroimaging morphometry and variants of choroid plexus in the cerebellopontine angles

Introduction

Protrusions of fourth ventricular choroid plexus through the foramina of Luschka are called ??Bochdalek??s flower basket?? (BochFB). The bulbous terminal expansions (cornucopiae) extend into the cerebellopontine angle (CPA) cisterns. We studied and reviewed the normal imaging anatomy, morphometry and anatomical variants of BochFB.

Methods

We retrospectively analysed normal brain imaging findings on axial pre- and post-contrast CT scans and enhanced axial T1-weighted MRIs of 200 patients. We assessed BochFB for: (a) calcification, (b) lateral extension, (c) enhancement pattern, (d) cornucopiae shape, (e) symmetry and (f) proximity to tortuous vertebral arteries and morphometry of cornucopiae size and length of BochFB limbs.

Results

BochFB calcification was found in 38?% of patients aged over 51?years. Lateral extension of BochFB into the CPA cistern was prominent in 75?% on CT and 96?% on MRI. The mean length of these extensions was 23.6?mm. BochFB enhanced strongly in 47?% on CT and 66?% on MRI. The BochFB cornucopiae were bulbous in 51?% on CT and 54?% on MRI. The mean width of bulbous cornucopiae was 3.5?mm. Bilateral BochFB symmetry was found in 71?% on CT and 80?% on MRI. Six to 8?% of tortuous left vertebral arteries were close to BochFB.

Conclusion

The cornucopiae are particularly well demonstrated on post-contrast MRI. However several sources of error in image interpretation may arise when imaging the normal BochFB on routine head CT and MRI. Difficulties in analysis arise especially on CT because of physiologic calcification, asymmetry, and the bulbous cornucopiae being mistaken for aneurysms.     

低场强MR在三叉神经痛病因诊断中的应用

目的 评估低场强MR在三叉神经痛病因诊断中的应用价值.资料与方法 对43例临床表现有三叉神经痛的患者行MRI检查,疼痛为间隙性或持续性.每例患者均行颅脑常规T_1WI、T_2WI及液体衰减反转恢复序列(FLAIR)扫描.阴性者加做三叉神经薄层扫描,其中有8例做了增强扫描.结果 阳性发现26例,阴性17例.26例中三叉神经脑池段周围血管压迫或接触14例,三叉神经鞘瘤2例,听神经瘤1例,桥前池胆脂瘤3例,蛛网膜囊肿2例,脑膜瘤2例,脑干脱髓鞘病变1例,脑干胶质瘤1例.结论 低场强MR对三叉神经痛原因的诊断有很高的价值,它不仅能发现三叉神经本身的病变,也能发现三叉神经周围组织病变对三叉神经的影响.     

颅内表皮样囊肿的CT诊断

目的:分析表皮样囊肿的CT表现并提高其诊断准确性。材料与方法:11例患者,其中,男性6例,女性5例,年龄介于25～65岁,均经采用GE1600C型扫描仪以OM为基线横断扫描,于平扫后行增强扫描。结果:11例患者的病灶均呈囊性低密度,其中,圆形病灶见于3例,扁平不规则形且境界欠清的病灶见于8例。后者中,1例的病灶位于枕大池,压迫四脑室并引起幕上脑积水。1例的病灶位于鞍上池及环池。其余患者的病灶均位于桥小脑角池且有沿蛛网膜下腔生长的趋势。结论:只要掌握表皮样囊肿的上述CT表现,便容易将其与蛛网膜囊肿,皮样囊肿,以及颅内其他囊性肿块相鉴别。     

Magnetic resonance imaging in acoustic neurinoma. Comparison with CT

MRI and CT were performed in 16 patients with 17 acoustic neurinomas. MRI was superior to CT in the detection of small acoustic neurinomas, in the demonstration of intracanalicular extension and in the differentiation with cerebellopontine angle meningiomas. Overall advantages of MRI over CT included better tissue contrast, absence of bone artifacts and easy multiplanar imaging.     

Differentiation of cerebellopontine angle neuromas and meningiomas with MR imaging

Postcontrast CT of the temporal bone is the neuroradiological study of choice for investigation of cerebellopontine angle (CPA) and internal auditory canal (IAC) lesions. Nonenhancing or small lesions may need CT combined with air or metrizamide cisternography for their detection. Magnetic resonance (MR) imaging has shown interesting capabilities as a noninvasive study for the visualization of the IAC, the neural bundle entering the canal, the brain stem, and cerebellum. In the present series of 24 cases, MR imaging detected the lesion in all 11 verified tumors. We feel that MR can replace invasive air and metrizamide cisternography in the diagnosis of CPA lesions and can help in the differentiation between acoustic neuromas and meningiomas.     

Benign solitary neurinomas of the sciatic popliteal nerves CT study

Summary Two cases of solitary benign neurinomas of the sciatic popliteal nerves are reported. Computed tomography (CT) confirmed the clinically suspected diagnosis of a tumor of nervous origin, and provided accurate preoperative location of these tumors.     

原发性面神经瘤的CT诊断与鉴别诊断(附13例分析)

目的:探讨原发性面神经瘤CT诊断及鉴别诊断价值。方法:搜集临床资料完整的原发性面神经瘤13例,每例患者均经手术病理证实。结果:共发现病灶15处,2例面神经瘤位于颅内桥小脑角区(CPA),面神经管内9例,2例位于腮腺实质内,其中多发病灶者2例病灶均位于乳突段和腮腺实质内。结论:CT检查对原发性面神经瘤的诊断及鉴别诊断有较大价值。     

Computed tomography of acoustic neurinoma

Thirty-seven patients with 39 acoustic neurinomas were studied with computed tomography (CT). Six tumors (15%) were seen on the nonenhanced scans and infusion of contrast material demonstrated 23 more tumors. Ten tumors (26%) were not seen as soft-tissue masses on the enhanced CT scans. However, these same 10 cases yielded 4 ipsilateral abnormal internal auditory canals when viewed with a bone window. Findings suggestive of acoustic neurinomas were found in 85% of proven sites. Important factors in the CT diagnosis of acoustic neurinomas are good-quality, motion-free scans, contrast enhancement and analysis of bone detail.