Abstract
Aim
Our aim was to assess the diagnostic utility of magnetic resonance imaging with complimentary magnetic resonance angiography (MRI/MRA) in the radiological evaluation of patients with pulsatile tinnitus (PT).
Materials and Methods
The present study was retrospectively conducted on 27 patients with pulsatile tinnitus. All patients showed normal otoscopic findings and were evaluated with magnetic resonance imaging (MRI) with complimentary magnetic resonance angiography (MRA), 9/27 (33.3%) patients were investigated by CT, and 12/27 (44.4%) were evaluated by angiography. All patients’ clinical investigation was reviewed to discard systemic causes of PT.
Results
All hard copies of MRI/MRA studies were evaluated. MRI/MRA detected the underlying etiology of subjective pulsatile tinnitus (PT) in 11/27 patients (40.7%), and 16/27 patients (59.5%) showed normal MRI/MRA examination. The most common cause was dural arteriovenous malformation (AFM) in 4/27 (14.8%) patients, high jugular bulbus in 2/27 (7.4%), aneurysm of internal carotid artery in 1/27 (3.7%), aberrant internal carotid artery in 1/27 (3.7%), vertebral artery hypoplasia in 2/27 (7.4%), and glomus tumor in 1/27 (3.7%). The statistical results of the present study showed that MRI/MRA had the following: 80% sensitivity, 88% specificity, 86% accuracy, 85% PPV, 83% NPV, and 15% error percentage for diagnosis of PT.
Conclusion
MRI/MRA was an effective radiological imaging method in detecting the underlying pathology of pulsatile tinnitus. Magnetic resonance may be considered a first line diagnostic imaging modality in the assessment of subjective pulsatile tinnitus.
1
Introduction
Tinnitus may be continuous or pulsatile (PT). It is classified into objective and subjective subtypes. These subtypes refer to the ability or inability respectively of the examiner to auscultate a vascular bruit in the periauricular or cervical neck region. Vascular lesions are the most frequent radiologically demonstrable cause of pulsatile tinnitus. These include congenital vascular anomalies (which may be arterial or venous), vascular tumors, and a variety of acquired vasculopathies .
Clinical diagnosis of PT is based on a complete neurotological evaluation, which includes clinical history, complete physical examination, with special attention to the otoscopic examination, auscultation of the external auditory canal and adjacent areas, palpation of the high cervical area and pre-auricular region .
The importance of investigating PT is justified by its higher association with identifiable and treatable causes when compared to non-pulsatile tinnitus. Besides, the misdiagnosis can be catastrophic, once it may be related to intracranial diseases, such as aneurysms and tumors .
Radiological investigation is important for the establishment of etiologic diagnosis . Angiography is more definitive and accurate, allowing the diagnosis of causes of PT. On the other hand, it is an invasive examination, with a considerable related morbidity rate . Computed tomography (CT) allows diagnosis of bone alterations associated to vascular anomalies, however it cannot detect arteriovenous malformations or arteriovenous fistulas of the dura, which are the most important causes of PT, especially in the presence of normal otoscopic findings .
MRI is a commonly used noninvasive imaging modality for diagnosis of PT that can be further enhanced by the use of magnetic resonance angiography (MRA). Magnetic resonance imaging (MRI) and cerebral angiography are imaging modalities often used to identify vascular lesions responsible for pulsatile tinnitus. Generally, angiography has been restricted to those cases when MRA is normal, once it may detect small abnormalities not shown in MRA. Subjective pulsatile tinnitus is often evaluated with less invasive tests such as MRI/MRA. However, objective pulsatile tinnitus is evaluated with more invasive tests such as cerebral angiography .
This study will review the MRI/MRA imaging findings in patients presenting with subjective or objective pulsatile tinnitus with normal otoscopic findings in an attempt to assess the diagnostic utility of MRI and MRA in the radiological evaluation of those patients.
2
Patients and methods
2.1
Study population
The present study was a retrospective review on the medical records and MRI/MRA studies of 27 patients who underwent radiological evaluation of pulsatile tinnitus between 2008 and 2011. Patients’ medical data were reviewed for the complaints and the physical findings at the time of presentation. There were 16 female (59.5%) and 11 male (40.7%) patients, with a mean age of 48 years (age range, 23–85 years). Tinnitus was unilateral in 23/27 patients (85.1%) and bilateral in 4/27 (14.8%) patients. The right ear was involved in 13 patients and the left ear was involved in 18. All patients had undergone clinical evaluation including a thorough history, otoscopy, and auscultation of the mastoid, head, neck, and chest with a stethoscope. Tinnitus was defined as pulsatile when the patient described sounds synchronous with the heart rate and as objective when heard by the examining physician. All patients’ records included complete audiometric evaluation, magnetic resonance imaging (MRI) exam with complimentary magnetic resonance angiography (MRA), 9/27 patients (33.3%) were investigated by CT, and 12/27 (44.4%)were evaluated by angiography. In order to discard systemic causes of PT, such as anemia and hyperthyroidism, all patients’ clinical investigation was reviewed, emphasizing the following general exams: complete blood count, glucose test, cholesterol, triglycerides, thyroid hormones. Ten patients (37%) were excluded, 2/27 patients (7.4%) due to incomplete series or their MRI/MRA examination, and 8/27 (29.6%) with clinical evidence of systemic causes of PT (5 with anemia and 3 with severe hypertension). Potential middle ear causes for tinnitus were excluded.
2.2
MRI examination
All hard copies of MRI/MRA studies were performed with 1 T Closed MR Imager (Gyroscan, Intera, Philips, Holland). All the patients were instructed to remove all metallic articles, e.g. hair pins and coins. They were asked about the presence of metallic prosthesis, coils or implants or any other articles interfering with MRI examination. The following imaging protocol was used: Axial T1WI (TR 510/TE 14, FOV 24 cm, Matrix 160 × 256, slice thickness 4 mm, band width 7.8); Axial and coronal T2WI (TR 4700/TE 110, FOV 24 cm, Matrix 128 × 256, slice thickness 4 mm, band width 7.8); STIR coronal and/or sagittal (TR 3500/TE 37, FOV 24 cm, Matrix 128 × 256, slice thickness 4 mm, band width 6.9); TOF MRA (TR43/TE 7, FOV 19 cm, Matrix 256, flip angle 45, overlap 2 mm). Intravenous Gadolinium (IV Gad) was given to all patients (OMNISCAN Gd-DTPA: Gadolinium-di-ethylene-triamine-penta-acetic acid), in a dose of about 1 ml/5 kg with a maximum dose of about 10 ml and a minimum dose of 3 ml. Post GAD evaluation was applied on T1WI.
2.3
Image analysis
All radiological studies of each patient including, digital subtraction angiography, computed tomography (CT), and MR I/MRA imaging, were reviewed. MR and MRA images of each patient were evaluated in one session by a radiologist who was aware of the clinical details. All images were reviewed with special attention to the carotid bifurcations, internal carotid artery course, transverse and sigmoid sinuses, jugular foramen, internal jugular vein, sella turcica, and temporal bones.
2.4
Standard of reference
DSA was considered a gold standard of reference in 12/27 (44.4%) patients, MDCT was considered as standard of reference for 2/27 patients (7.4%), and histopathology for 1/27 patients (3.7%).
2
Patients and methods
2.1
Study population
The present study was a retrospective review on the medical records and MRI/MRA studies of 27 patients who underwent radiological evaluation of pulsatile tinnitus between 2008 and 2011. Patients’ medical data were reviewed for the complaints and the physical findings at the time of presentation. There were 16 female (59.5%) and 11 male (40.7%) patients, with a mean age of 48 years (age range, 23–85 years). Tinnitus was unilateral in 23/27 patients (85.1%) and bilateral in 4/27 (14.8%) patients. The right ear was involved in 13 patients and the left ear was involved in 18. All patients had undergone clinical evaluation including a thorough history, otoscopy, and auscultation of the mastoid, head, neck, and chest with a stethoscope. Tinnitus was defined as pulsatile when the patient described sounds synchronous with the heart rate and as objective when heard by the examining physician. All patients’ records included complete audiometric evaluation, magnetic resonance imaging (MRI) exam with complimentary magnetic resonance angiography (MRA), 9/27 patients (33.3%) were investigated by CT, and 12/27 (44.4%)were evaluated by angiography. In order to discard systemic causes of PT, such as anemia and hyperthyroidism, all patients’ clinical investigation was reviewed, emphasizing the following general exams: complete blood count, glucose test, cholesterol, triglycerides, thyroid hormones. Ten patients (37%) were excluded, 2/27 patients (7.4%) due to incomplete series or their MRI/MRA examination, and 8/27 (29.6%) with clinical evidence of systemic causes of PT (5 with anemia and 3 with severe hypertension). Potential middle ear causes for tinnitus were excluded.
2.2
MRI examination
All hard copies of MRI/MRA studies were performed with 1 T Closed MR Imager (Gyroscan, Intera, Philips, Holland). All the patients were instructed to remove all metallic articles, e.g. hair pins and coins. They were asked about the presence of metallic prosthesis, coils or implants or any other articles interfering with MRI examination. The following imaging protocol was used: Axial T1WI (TR 510/TE 14, FOV 24 cm, Matrix 160 × 256, slice thickness 4 mm, band width 7.8); Axial and coronal T2WI (TR 4700/TE 110, FOV 24 cm, Matrix 128 × 256, slice thickness 4 mm, band width 7.8); STIR coronal and/or sagittal (TR 3500/TE 37, FOV 24 cm, Matrix 128 × 256, slice thickness 4 mm, band width 6.9); TOF MRA (TR43/TE 7, FOV 19 cm, Matrix 256, flip angle 45, overlap 2 mm). Intravenous Gadolinium (IV Gad) was given to all patients (OMNISCAN Gd-DTPA: Gadolinium-di-ethylene-triamine-penta-acetic acid), in a dose of about 1 ml/5 kg with a maximum dose of about 10 ml and a minimum dose of 3 ml. Post GAD evaluation was applied on T1WI.
2.3
Image analysis
All radiological studies of each patient including, digital subtraction angiography, computed tomography (CT), and MR I/MRA imaging, were reviewed. MR and MRA images of each patient were evaluated in one session by a radiologist who was aware of the clinical details. All images were reviewed with special attention to the carotid bifurcations, internal carotid artery course, transverse and sigmoid sinuses, jugular foramen, internal jugular vein, sella turcica, and temporal bones.
2.4
Standard of reference
DSA was considered a gold standard of reference in 12/27 (44.4%) patients, MDCT was considered as standard of reference for 2/27 patients (7.4%), and histopathology for 1/27 patients (3.7%).
3
Results
3.1
Clinical features
The present study included 27 patients (16/27 (59.5%) were female and 11/26 (40.7%) male), they ranged in age from 23 to 85 years. Pulsatile tinnitus (PT) was present in all 100% patients. It was clinically classified as subjective in 10/27 patients (37%) and objective in 17/27 patients (62.9%). It was unilateral in 23/27 (85.1%) patients and bilateral in 4/27 (14.8%). The right ear was involved in 13 patients and the left ear was involved in 18 patients. Compliant duration was ranged from 1 to 2 years in 17/27 (62.9%) patients and more than 2 years in the remaining 10/27 (37%) patients. All patients (100%) in our series complained of rhythmical noise in their ears that beats in time with their pulse, 18/27 (66.6%) ear ringing, or clicking 10/27 (37%) dizziness, 1/27 (3.7%) vertigo, 3/27 (11.1%) headaches, and 2/27 (7.4%) had past history of head trauma. There was no history of previous ear operation. All patients had normal otoscopic examination ( Table 1 ).
| Patient | No. |
|---|---|
| Sex: | |
| Male | 16/27 (59.5%) |
| Female | 11/26 (40.7%) |
| Pulsatile tinnitus (PT): | |
| Subjective | 10/27 (37%) |
| Objective | 17/27 (62.9%) |
| Site: | |
| Unilateral | 23/27 (85.1%) |
| Bilateral | 4/27 (14.8%) |
| RT side | 13 (48.1%) |
| LT side | 18 (66.6%) |
| Duration: | |
| 1–2 years | 17/27 (62.9%) |
| More than 2 years | 10/27 (37%) |
| Symptoms: | |
| Rhythmical noise in the ear | 27/27 (100%) |
| Ear ringing, or clicking | 18/27 (66.6%) |
| Dizziness | 10/27 (37%) |
| Vertigo | 1/27 (3.7%) |
| Headache | 3/27 (11.1%) |
| Past history: | |
| Head trauma | 2/27 (7.4%) |
| Ear operation | 0/27 |
| Radiological examination: | |
| CT | 10/27 (37%) |
| MRI/MRA | 27/27 (100%) |
| DSA | 12/27 (44.4%) |
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