Contrast-enhanced MR imaging of the facial nerve in 11 patients with Bell's palsy

Contrast-enhanced MR images (at 1.5 T) were obtained in 11 patients with facial palsy. The group included five people with acute idiopathic facial (Bell's) palsy, three with chronic idiopathic facial palsy, and one each with acute facial palsy after local radiation therapy, acute facial palsy resulting from herpes zoster virus infection, and facial palsy caused by facial neuroma. Eight of the 11 patients demonstrated marked enhancement of the affected facial nerve from the labyrinthine portion through the descending canal. Three patients also demonstrated mild enhancement of the distal canalicular portion of the facial nerve, simulating small distal acoustic neuromas. No difference in the pattern of enhancement between the acute or chronic Bell's palsy patients was seen. Radiographic resolution appeared to lag behind clinical resolution. The facial neuroma appeared distinct from the other lesions as a focally enhancing mass. The enhancement pattern in the Bell's group correlated with the histopathologic features of Bell's palsy and is consistent with the viral hypothesis of the syndrome. Thin-section contrast-enhanced MR scans are recommended for individuals with atypical presentation of facial paralysis. In the proper clinical setting, contrast-enhanced MR imaging may permit a positive radiographic diagnosis of Bell's palsy, which has previously been a diagnosis of exclusion.     

Facial nerve palsy: evaluation by contrast-enhanced MR imaging

AIM: The purpose of this study was to investigate the value of contrast-enhanced magnetic resonance (MR) imaging in patients with peripheral facial nerve palsy. MATERIALS AND METHODS: MR imaging was performed in 147 patients with facial nerve palsy, using a 1.0 T unit. All of 147 patients were evaluated by contrast-enhanced MR imaging and the pattern of enhancement was compared with that in 300 control subjects evaluated for suspected acoustic neurinoma. RESULTS: The intrameatal and labyrinthine segments of the normal facial nerve did not show enhancement, whereas enhancement of the distal intrameatal segment and the labyrinthine segment was respectively found in 67% and 43% of patients with Bell's palsy. The geniculate ganglion or the tympanic-mastoid segment was enhanced in 21% of normal controls versus 91% of patients with Bell's palsy. Abnormal enhancement of the non-paralyzed facial nerve was found in a patient with bilateral temporal bone fracture. CONCLUSION: Enhancement of the distal intrameatal and labyrinthine segments is specific for facial nerve palsy. Contrast-enhanced MR imaging can reveal inflammatory facial nerve lesions and traumatic nerve injury, including clinically silent damage in trauma.     

3D-FT MRI of the facial nerve

Contrast-enhanced 3D-FT MRI of the intrapetrous facial nerve was obtained in 38 patients with facial nerve disease, using a 1.0 T magnet and fast gradient-echo acquisition sequences. Contiguous millimetric sections were obtained, which could be reformatted in any desired plane. Acutely ill patients, were examined within the first 2 months, included: 24 with Bell's palsy and 6 with other acute disorders (Herpes zoster, trauma, neuroma, meningeal metastasis, middle ear granuloma). Six patients investigated more than a year after the onset of symptoms included 3 with congenital cholesteatoma, 2 with neuromas and one with a chronic Bell's palsy. The lesion was found incidentally in two cases (a suspected neurofibroma and a presumed drop metastasis from an astrocytoma). Patients with tumours had nodular, focally-enhancing lesions, except for the leptomeningeal metastasis in which the enhancement was linear. Linear, diffuse contrast enhancement of the facial nerve was found in trauma, and in the patient with a middle ear granuloma. Of the 24 patients with an acute Bell's palsy 15 exhibited linear contrast enhancement of the facial nerve. Three of these were lost to follow-up, but correlation of clinical outcome and contrast enhancement showed that only 4 of the 11 patients who made a complete recovery and all 10 patients with incomplete recovery demonstrated enhancement. Possible explanations for these findings are suggested by pathological data from the literature. 3D-FT imaging of the facial nerve thus yields direct information about the of the nerve condition and defines the morphological abnormalities. It can also demonstrate contrast enhancement which seems to have some prognostic value in acute idiopathic Bell's palsy.     

MRI of the facial nerve in idiopathic facial palsy

The purpose of this prospective study was to define the enhancement pattern of the facial nerve in idiopathic facial paralysis (Bell's palsy) on magnetic resonance (MR) imaging with routine doses of gadolinium-DTPA (0.1 mmol/kg). Using 0.5T imager, 24 patients were examined with a mean interval time of 13.7 days between the onset of symptoms and the MR examination. Contralateral asymptomatic facial nerves constituted the control group and five of the normal facial nerves (20.8%) showed enhancement confined to the geniculate ganglion. Hence, contrast enhancement limited to the geniculate ganglion in the abnormal facial nerve (3 of 24) was referred to as equivocal. Not encountered in any of the normal facial nerves, enhancement of other segments alone or associated with geniculate ganglion enhancement was considered to be abnormal and noted in 70.8% of the symptomatic facial nerves. The most frequently enhancing segments were the geniculate ganglion and the distal intracanalicular segment. Correspondence to: I. Saatçi     

Intensity of MR contrast enhancement does not correspond to clinical and electroneurographic findings in acute inflammatory facial nerve palsy.

PURPOSETo determine the value of MR contrast enhancement in predicting the course of acute inflammatory facial nerve palsy and in selecting patients for surgical decompression.METHODSSix patients with an acute inflammatory incomplete or complete peripheral facial nerve palsy (five idiopathic and one herpetic in origin) had repeated MR imaging studies with and without contrast enhancement, electroneurography, and clinical examinations to establish a connection between the intensity of contrast enhancement on MR images, the clinical condition, and the electrophysiological data. The examinations were performed every second day starting on the first day of admission until clinical recovery was proved by clinical deblockage (spontaneous clinical improvement). The last examination was performed 3 months after the onset of the facial nerve palsy.RESULTSAn abnormal, very intense contrast enhancement of the facial nerve was always present in the distal intrameatal and proximal tympanic segments and in the geniculate ganglion. The labyrinthine segment exhibited a mild to moderate enhancement, and the distal tympanic and mastoid segments showed a moderate to intense enhancement. The intensity of contrast enhancement did not correspond to the severity, duration, or course of the facial nerve palsy, and the electroneurographic data had no predictive value in indicating the severity of the inflammatory process. Three months after clinical recovery, a persistent and more or less unchanged or even slightly more intense contrast enhancement was observed.CONCLUSIONThe long-lasting intense contrast enhancement seen in the facial nerve segments of patients who have acute peripheral inflammatory facial nerve palsy is explained by a two-phase breakdown of the blood-nerve barrier.     

High-intensity facial nerve lesions on T2-weighted images in chronic persistent facial nerve palsy

Our aim was to estimate the value of MRI in detecting irreversibly paralysed facial nerves. We examined 95 consecutive patients with a facial nerve palsy (14 with a persistent palsy, and 81 with good recovery), using a 1.0 T unit, with T2-weighted and contrast-enhanced T1-weighted images. The geniculate ganglion and tympanic segment had gave high signal on T2-weighted images in the chronic stage of persistent palsy, but not in acute palsy. The enhancement pattern of the facial nerve in the chronic persistent facial nerve palsy is similar to that in the acute palsy with good recovery. These findings suggest that T2-weighted MRI can be used to show severely damaged facial nerves. Received: 13 December 1999 Accepted: 2 May 2000     

Idiopathic,herpetic, and HIV-associated facial nerve palsies: abnormal MR enhancement patterns.

PURPOSETo determine specific criteria that can be used to define normal versus abnormal MR contrast enhancement of the facial nerve.METHODSTwenty-three patients with acute unilateral inflammatory peripheral facial nerve palsy were examined on a 1.5-T MR using multiplanar T1-weighted spin-echo sequences before and after injection of gadopentetate dimeglumine. These MR patterns were compared with those of healthy control subjects.RESULTSThe normal facial nerve usually showed a mild to moderate enhancement of the geniculate ganglion and the tympanic-mastoid segment. The intracanalicular-labyrinthine segment did not enhance. All patients showed abnormal enhancement of the distal intracanalicular and the labyrinthine segment. An intense enhancement could be observed in the geniculate ganglion and the proximal tympanic segment, especially in herpetic palsy. Associated enhancement of the vestibulocochlear nerve was seen in herpetic and idiopathic palsy. Enhancement of the inner ear structures was detected only in herpetic palsy.CONCLUSIONSAbnormal contrast enhancement of the distal intracanalicular and the labyrinthine facial nerve segment is observed in all patients and is the only diagnostically reliable MR feature proving an inflammatory facial nerve lesion. The intense enhancement of the geniculate ganglion and the proximal tympanic segment is possibly correlated with the reactivation of the latent infection in the sensory ganglion. The abnormal enhancement results from breakdown of the blood-peripheral nerve barrier and/or from venous congestion in the venous plexuses of the epi- and perineurium.     

T2-weighted three-dimensional fast spin-echo MR in inflammatory peripheral facial nerve palsy.

PURPOSEOur objective was to identify histologically and intraoperatively verified focal nerve thickening of the distal intrameatal segment on three-dimensional fast spin-echo (FSE) T2-weighted MR images as a new diagnostic criterion in patients with inflammatory peripheral facial nerve palsy.METHODSTwenty-two patients with clinically diagnosed unilateral (n = 20) or bilateral (n = 2) inflammatory peripheral facial nerve palsy were examined on a 1.5-T MR imager using noncontrast and contrast-enhanced T1-weighted SE sequences and 3-D T2-weighted FSE sequences with secondary reformations. Abnormal contrast enhancement and possible focal nerve thickening of the distal intrameatal segment, labyrinthine nerve segment, and geniculate ganglion region were analyzed prospectively.RESULTSIn all patients, the T1-weighted postcontrast SE images showed characteristic smooth, linear, abnormally intense contrast enhancement of the distal intrameatal segment, indicating peripheral inflammatory nerve palsy. In 23 nerves (96%) a focal bulbous nerve thickening of the distal intrameatal segment was observed on 3-D T2-weighted FSE images. In 100% of patients with peripheral inflammatory facial nerve palsy, postcontrast T1-weighted SE images showed a smooth, linear, and abnormally intense contrast enhancement of the distal intrameatal segment; reformatted very thin 3-D T2-weighted FSE images showed a focal bulbous nerve thickening of the distal intrameatal segment in 96% of patients. These findings corresponded to intraoperative and histologic findings.CONCLUSIONThree-dimensional T2-weighted FSE sequences are fast and cheap compared with T1-weighted postcontrast images, but secondary reformations are time-consuming and require exact anatomic knowledge for careful analysis of the different nerve segments.     

Enhancement pattern of the normal facial nerve at 3.0 T temporal MRI

The purpose of this study was to evaluate the enhancement pattern of the normal facial nerve at 3.0 T temporal MRI. We reviewed the medical records of 20 patients and evaluated 40 clinically normal facial nerves demonstrated by 3.0 T temporal MRI. The grade of enhancement of the facial nerve was visually scaled from 0 to 3. The patients comprised 11 men and 9 women, and the mean age was 39.7 years. The reasons for the MRI were sudden hearing loss (11 patients), Méniàre''s disease (6) and tinnitus (7). Temporal MR scans were obtained by fluid-attenuated inversion-recovery (FLAIR) and diffusion-weighted imaging of the brain; three-dimensional (3D) fast imaging employing steady-state acquisition (FIESTA) images of the temporal bone with a 0.77 mm thickness, and pre-contrast and contrast-enhanced 3D spoiled gradient record acquisition in the steady state (SPGR) of the temporal bone with a 1 mm thickness, were obtained with 3.0 T MR scanning. 40 nerves (100%) were visibly enhanced along at least one segment of the facial nerve. The enhanced segments included the geniculate ganglion (77.5%), tympanic segment (37.5%) and mastoid segment (100%). Even the facial nerve in the internal auditory canal (15%) and labyrinthine segments (5%) showed mild enhancement. The use of high-resolution, high signal-to-noise ratio (with 3 T MRI), thin-section contrast-enhanced 3D SPGR sequences showed enhancement of the normal facial nerve along the whole course of the nerve; however, only mild enhancement was observed in areas associated with acute neuritis, namely the canalicular and labyrinthine segment. Imaging of the facial nerve is useful for the evaluation of pathological conditions. MRI of the facial nerve is usually performed selectively in cases of peripheral facial nerve palsy in patients with an atypical presentation or delayed recovery to exclude space-occupying lesions. The gadolinium-diethylene triamine pentaacetic acid (Gd-DTPA) contrast pulse sequence is the most informative MRI procedure for evaluation of facial nerve pathology [1]. Although many studies involving MRI of normal and paralysed facial nerves have been performed [2–10], there are no reports on the enhancement pattern of normal and abnormal facial nerves with 3.0 T MR scanning. The 3.0 T MR scan provides a higher signal-to-noise ratio (SNR), which allows a higher imaging matrix, thinner slices and a shorter time for scanning [11].The purpose of this retrospective study was to evaluate the enhancement pattern of normal facial nerves, bilaterally, with 3.0 T temporal MRI.     

Etude angiographique des paralysies faciales

Summary Many arguments lead us to think that a possible etiologic factor in idiopathic Bell's palsy is the ischemia of the facial nerve and that angiography could help in diagnosis: (1) the rapid progress of the paralysis; (2) the correlation between Bell's palsy occurring after embolization of the internal maxillary artery, the middle meningeal artery, the occipital or posterior auricular artery, and their participation in the blood supply of the facial nerve; (3) the already known ischemic third nerve paralysis reported in diabetes and extending further to the facial nerve.Even if it is technically impossible to study Bell's palsy by angiography, it is interesting to understand and consider some complications of embolization and perhaps to envisage a new kind of treatment.     

MR imaging for evaluation of severe facial nerve damage in patients with facial nerve palsy

PURPOSE: To evaluate the usefulness of MR imaging for the detection of severe facial nerve damage in patients with facial nerve palsy. MATERIALS AND METHODS: We retrospectively reviewed 26 consecutive patients with facial nerve palsy (13 non-responders and 13 responders). T1-weighted, T2-weighted, and postcontrast T1-weighted images were obtained in all patients. FLAIR images were also obtained in 3 non-responders. RESULTS: The geniculate ganglion, labyrinthine segment, and tympanic segment or mastoid segment showed high signal intensity on T2-weighted images in 9 of 13 non-responders, whereas high signal intensity of the nerve was only seen in 1 of 13 responders. FLAIR imaging revealed high signal intensity lesions of the distal intrameatal segment in 2 non-responders. Contrast enhancement of the facial nerve showed a similar pattern in non-responders and responders. High signal intensity lesions on T2-weighted or FLAIR images showed enhancement on postcontrast T1-weighted images. CONCLUSION: These results suggest that a high signal intensity area on T2-weighted images is a marker of severe facial nerve damage. FLAIR imaging is useful for identification of T2-prolongation in the distal intrameatal segment.     

Magnetic resonance imaging of the intratemporal facial nerve in idiopathic peripheral facial palsy

The aim of this study was to investigate the prevalence of facial nerve involvement with gadolinium-enhanced magnetic resonance imaging (Gd-MRI) in patients with idiopathic peripheral facial palsy (IPFP), and to discuss the localization and the pattern of enhancement. A total of 13 patients (9 female, 4 male) with IFPF were included in this study. Topographic tests and electromyography (EMG) were performed, and MRI was taken. Ten subjects whose cranial MRIs were taken for nonorganic pathology served as the control group. Twelve of 13 paralytic facial nerves had enhancement on postcontrast images. Two facial nerves of the control group demonstrated enhancement. We found a correlation between the enhancement of the facial nerve and the time for recovery. The average time from the onset of facial palsy to the recovery in patients with enhancement was 14 weeks, whereas it was 6 weeks in patient with no enhancement. Finally, all patients had complete recovery of the facial nerve function. We concluded that contrast enhancement of the paralytic facial nerve can be a radiological sign of a neural inflammation and may indicate a prolonged recovery.     

Bell palsy: quantitative analysis of MR imaging data as a method of predicting outcome

PURPOSE: To assess the prognostic value of quantitative analyses of region-of-interest (ROI) magnetic resonance (MR) imaging data in patients with acute facial nerve palsy. MATERIALS AND METHODS: In a single-blinded study, MR images were obtained in 39 patients (32 men and seven women; age range, 18-75 years; average age, 37.9 years) with acute facial nerve palsy. MR images were obtained before the 6th day of illness, on the first day of standard inpatient treatment with high-dose steroids. Signal intensity (SI) was measured at ROIs in each of five segments (internal auditory canal [IAC]; geniculate ganglion; and labyrinth, tympanic, and mastoid segments) of the intratemporal portion of the facial nerve and quantitatively analyzed. The SI measurements in the five segments were summed and divided by 100 to provide a basis for establishing an MR imaging index. SI increases and MR imaging indexes were compared with available clinical findings and electrophysiologic data. RESULTS: Data for all 39 patients could be analyzed. The MR imaging index was significantly higher in patients with poor outcomes than in patients with favorable outcomes (specificity, 97%; sensitivity, 75%; P <.01). The SI increases in the IAC were significantly different between patients who progressed to full recovery (mean increase, 45.7%) and patients who developed chronic facial paralysis (mean increase, 156.5%) (sensitivity, 100%; specificity, 97%; P <.001). The results of differentiating between patients with good and those with poor outcomes on the basis of SI measurements in the IAC were found to be in complete agreement with electrophysiologic data. CONCLUSION: Quantitative analysis of ROI MR imaging data is a valid method of predicting the outcome of acute facial nerve palsy during the first days after onset of symptoms and thus at a time when it is not yet possible to obtain valuable prognostic information by using electrophysiologic methods.     

MR imaging of facial nerve enhancement in Bell palsy or after temporal bone surgery

The authors evaluated magnetic resonance (MR) images obtained with intravenously administered gadolinium in ten patients who had facial paralysis and no facial nerve tumor. In patients with either Bell palsy (four patients) or facial paralysis after temporal bone surgery (six patients), intratemporal facial nerve enhancement was seen. Facial nerve enhancement on MR images proved to be a nonspecific finding.     

Gd-DTPA enhancement of the cisternal portion of the oculomotor nerve on MR imaging.

PURPOSE: To describe a radiographic finding--enhancement of the cisternal portion of the third cranial nerve on postcontrast MR--and to correlate it with patients' clinical symptoms and ultimate diagnosis. MATERIALS AND METHODS: Thirteen consecutive patients with enhancement of the cisternal portion of the third cranial nerve on postcontrast MR were retrospectively identified; 50 control patients referred for pituitary microadenomas were also retrospectively reviewed. FINDINGS: The enhancement was bilateral in six patients and unilateral in seven patients. Four of the six patients with bilateral enhancement had unilateral oculomotor nerve palsies; none had bilateral third cranial nerve palsy. Five of the seven patients with unilateral enhancement had ipsilateral third nerve palsies. Of the nine patients with third nerve palsies, the pupil was involved in four patients. Follow-up studies were available in six patients, four of whom had third nerve palsy. Resolution of the enhancement correlated with resolution of the symptoms in two patients. The patients' underlying diagnoses were lymphoma (four), leukemia (one), viral meningitis (one), neurofibromatosis (two), inflammatory polyneuropathy-HIV related (one), ophthalmoplegic migraine (one), Tolosa-Hunt syndrome (one), coccidioidomycosis (one), and diabetes (one). No enhancement was seen in any of the controls. CONCLUSION: Enhancement of the cisternal segment of the third cranial nerve is always abnormal, revealing an underlying inflammatory or neoplastic process. However, it is not always associated with clinically apparent oculomotor nerve dysfunction.     

Enhancement along the normal facial nerve in the facial canal: MR imaging and anatomic correlation.

Normal facial nerves are reported to show no enhancement at magnetic resonance (MR) imaging, in contradiction to the authors' clinical experience. To investigate this inconsistency, the authors searched MR imaging files and clinical records to find patients who underwent MR imaging of the temporal bone (at 1.5 T) before and after intravenous administration of gadopentetate dimeglumine and who had bilateral clinically normal facial nerves. When the MR images of 93 patients (186 facial nerves) were analyzed subjectively, 142 nerves (76%) were visibly enhanced along at least one segment of the facial nerve within the facial canal; the nerves of 64 of the 93 patients (69%) showed right-left asymmetry in enhancement, which was inhomogeneously distributed along each nerve. The facial nerve in the cerebellopontine angle cistern and in the internal auditory canal, as well as in the visualized proximal portion of the extracranial facial nerve, showed no enhancement. Comparison with reference anatomic sections showed that this enhancement pattern corresponded exactly to the topography of the circumneural facial arteriovenous plexus and should not necessarily be considered a sign of anatomic abnormality.     

颞骨内面神经病变的影像学表现

目的总结分析面神经病变的影像学检查方法和表现,提高诊断准确性。资料与方法回顾性分析31例经手术病理或临床跟踪随访证实的面神经病变的CT和MRI表现,31例行MR扫描,其中28例行平扫和增强扫描,3例仅行平扫;19例行CT扫描。结果（1）面神经损伤13例,8例行CT扫描,6例显示面神经管骨折,2例表现正常;13例MRI扫描均表现为面神经增粗,其中10例增强扫描显示面神经明显强化。（2）面神经炎14例,7例行CT扫描,1例因岩尖胆脂瘤致面神经管迷路段、前膝部、鼓室段前部骨质破坏,6例面神经管未见异常;14例MRI增强扫描显示面神经节段性异常强化。（3）面神经鞘瘤4例,CT表现为受累面神经管骨质破坏和软组织肿块;MRI表现为面神经节段性增粗,呈长T1、长T2信号,信号不均匀,增强后不均匀强化。经统计学处理,MRI显示颞骨内面神经病变明显优于CT（P＜0．01）。结论HRCT可显示面神经管的异常,MRI尤其是MR增强扫描可显示面神经病变的形态、部位、范围及强化表现,有助于病变的诊断和鉴别诊断。     

Comparison of contrast-enhanced T1-weighted and 3D constructive interference in steady state images for predicting outcome after hearing-preservation surgery for vestibular schwannoma

We compared contrast-enhanced T1-weighted and 3D constructive interference in steady state (CISS) sequences for demonstrating possible prognostic factors in hearing-preservation surgery for vestibular schwannoma. We studied 22 patients with vestibular schwannomas having hearing-preservation surgery. Postoperatively six (27%) had a facial palsy and eight (36%) had hearing loss. There was a significant correlation between the size of the tumour and facial palsy (r=–0.72). Both techniques adequately demonstrated all tumours. Involvement of the fundus of the internal auditory canal (IAC) and a small distance between the lateral border of the tumour and the fundus were correlated significantly with hearing loss (r=–0.81 and –0.75, respectively). The 3D-CISS sequence, by virtue of its high contrast resolution was superior to T1-weighted images (P<0.05) for detection of the fundal involvement. The direction of displacement of the facial nerve did not correlate with facial palsy or hearing loss. We think that 3D-CISS images better show the features influencing surgical outcome, but that contrast-enhanced T1-weighted images are required for diagnosis.     

MR of oculomotor nerve palsy.

PURPOSETo assess the utility of MR in third cranial nerve palsy.METHODSWe reviewed precontrast and postcontrast MR of 50 patients with third cranial nerve palsy.RESULTSMR demonstrated an appropriate lesion in 32 cases. Of these patients, 6 had brain stem lesions and 15 had involvement of the nerve in the cavernous sinus; lesions of the cisternal segment of the nerve were present in 11 patients, with enhancement of this segment observed in 9 patients. An inflammatory or infiltrative source of the palsy was indicated in 19 of these 32 cases. Of 7 patients with pupillary involvement suggestive clinically of a compressive lesion, 4 demonstrated thickening and enhancement consistent with an infiltrative lesion of the nerve. Eighteen patients with pupil-sparing third cranial nerve palsies and a history of diabetes or vascular disease had normal MR findings, with no enhancement of the third cranial nerve observed.CONCLUSIONSPatients who do not have a history of diabetes or hypertension and in whom a complete or incomplete third cranial nerve palsy develops with or without pupil sparing should undergo MR imaging initially (unless there are clear symptoms or signs of subarachnoid hemorrhage) to exclude the presence of an infiltrative lesion or intraparenchymal process. Patients who have a history of vascular disease and a clinical presentation that is suggestive of an ischemic event may be observed initially, but should undergo imaging if improvement does not occur within 3 months.     

MR imaging of primary trochlear nerve neoplasms

We present the clinical, anatomic, and MR imaging findings in six patients with seven primary trochlear nerve neoplasms, as well as the MR and clinical criteria that serve to establish the diagnosis of these rare cranial nerve neoplasms. Three patients had a history of neurofibromatosis and five patients had clinical evidence of a trochlear nerve palsy. Six of seven neoplasms produced localized, fusiform enlargement of the proximal cisternal segments of the trochlear nerves. The lesions that were visible on noncontrast MR scans (T1-, T2-, and proton density-weighted) had signal intensities that were virtually identical to normal brain parenchyma. All lesions showed intense, homogeneous enhancement on contrast-enhanced scans. Contrast-enhanced imaging was necessary for the detection of five of seven lesions and greatly increased the value of the MR study in all six patients.