OBJECTIVES: The aim of this study was to emphasize the necessity of a standard in segmentation threshold and algorithm for measuring volume and surface area of mastoid air cell system (MACS). METHODS: First, we obtained axial computed tomography scans of 54 normal temporal bones from 27 subjects. Then, we manipulated Hounsfield units (HU) image data in DICOM (digital imaging and communications in medicine) files directly using our program. The volume and surface area of MACS were computed and compared at segmentation thresholds (HU) from -700 to 0 at intervals of 50 using 2 algorithms; square pixel based (SP) algorithm and marching square (MS) algorithm. RESULTS: No significant difference was found between the volumes computed by SP and MS algorithms at each segmentation threshold. The surface area computed by SP algorithm, however, was significantly larger than that by MS algorithm. We could minimize this significant difference through a modification of the SP algorithm. As the lower HU threshold value was set, the smaller volume was measured. The surface area showed a plateau at a threshold of approximately -200 HU. The segmentation threshold had greater influence on the measured volume of MACS than the algorithm did. CONCLUSION: A standard method for measuring volume and surface area of MACS is thought to be necessary. We suggest that the MS algorithm and -200 HU of the threshold could be a standard in the measurement of volume and surface area of MACS.
Mastoid* ; Organ Size ; Temporal Bone

PURPOSE: To compare the enhancement pattern of normal facial nerves on 3D-FLAIR and 3D-T1-FFE-F) sequences at 3.0 T MR units. MATERIALS AND METHODS: We assessed 20 consecutive subjects without a history of facial nerve abnormalities who underwent temporal bone MRI with contrast enhancement between January 2008 and March 2009. Two neuroradiologists independently reviewed pre-/post-enhanced 3D-T1-FFE-FS and 3D-FLAIR images respectively with 2-week interval to assess the enhancement of normal facial nerves divided into five anatomical segments. The degree of enhancement in each segment was graded as none, mild or strong, and the results of 3D-FLAIR and 3D-T1-FFE-FS image sets were compared. RESULTS: On 3D-FLAIR images, one of the two reviewers observed mild enhancement of the genu segment in two (10%) subjects. On 3D-T1-FFE-FS images, at least one segment of the facial nerve was enhanced in 13 (65%) subjects. At least one reviewer found that 17 of the 100 segments showed enhancement on 3D-T1-FFE-FS images, with the mastoid segment being the most commonly enhanced. Interobserver agreement on 3D-T1-FFE-FS images was good for enhancement of the normal facial nerve (kappa= 0.589). CONCLUSION: In contrast to 3D-T1-FFE-FS, normal facial nerve segments rarely showed enhancement on 3D-FLAIR images.
Facial Nerve ; Mastoid ; Temporal Bone

The rhabdomyosarcoma(RMS), a leading malignant soft tissue tumor in the pediatric population, occurs most commonly in the craniocervical region. RMS has involved the temporal bone approximately 7% in the literature. Petrous bone invasion was very rare and the overall outcome was always fatal, in spite of the efficacy of multimodality therapy, until recent years. The authors report a case of primary RMS in the temporal bone invading petrous bone and the result of multimodality treatment.
Petrous Bone* ; Rhabdomyosarcoma* ; Temporal Bone*

Congenital cholesteatomas of mastoid origin are extremely rare. We reported one in 2007 and experienced an additional case. A male presented with a 5-month history of right-sided ear discharge. Computed tomography of the temporal bone showed a soft tissue density occupying the mastoid tip. At surgery, the cholesteatoma sac was completely isolated from the mastoid antrum and lateral air cell in the mastoid tip area. We now doubt the rarity of this entity. With a brief literature review, we consider how the cholesteatoma localizes to the tip of the mastoid bone.
Cholesteatoma* ; Ear ; Humans ; Male ; Mastoid* ; Temporal Bone

BACKGROUND AND OBJECTIVES: The purpose of the study was to compare the mastoid air-cell volume of the patients with superior semicircular canal dehiscence syndrome (SCDS) and that of the control patients with otosclerosis and temporal bone (TB) fracture. SUBJECTS AND METHODS: Ten patients with SCDS were enrolled and 10 patients with bilateral otosclerosis and TB fracture were selected as control groups by age and sex matching. To measure the mastoid air-cell volume, 3D reconstruction software was used. RESULTS: In 10 patients with SCDS, the mean age was 44.5 years, ranging from 16 to 79 years (M : F=4 : 6). Mean mastoid air-cell volume in the SCDS side was 3319.9 mm3, whereas 4177.2 mm3 in the normal side (p=0.022). Mean mastoid air-cell volume in the right side of otosclerosis patients was 6594.3 mm3 and it was not different from 6380.5 mm3 in the left side (p=0.445). Mean mastoid air-cell volume in normal side of TB fracture was 6477.2 mm3. The mastoid air-cell volume in the SCDS side was significantly smaller than that of otosclerosis and TB fracture patients (p=0.009, p=0.002, respectively). The mastoid air-cell volume in the normal side of SCDS was significantly smaller than that of TB fracture (p=0.019), but not significant with that of otosclerosis (p=0.063). CONCLUSIONS: Our findings revealed that the mastoid air-cell volume in the SCDS side was significantly smaller than control group, which suggest that the decreased mastoid pneumatization is closely related to the generation of SCDS.
Humans ; Mastoid ; Otosclerosis ; Semicircular Canals ; Temporal Bone

BACKGROUND AND OBJECTIVES: The purpose of the study was to compare the mastoid air-cell volume of the patients with superior semicircular canal dehiscence syndrome (SCDS) and that of the control patients with otosclerosis and temporal bone (TB) fracture. SUBJECTS AND METHODS: Ten patients with SCDS were enrolled and 10 patients with bilateral otosclerosis and TB fracture were selected as control groups by age and sex matching. To measure the mastoid air-cell volume, 3D reconstruction software was used. RESULTS: In 10 patients with SCDS, the mean age was 44.5 years, ranging from 16 to 79 years (M : F=4 : 6). Mean mastoid air-cell volume in the SCDS side was 3319.9 mm3, whereas 4177.2 mm3 in the normal side (p=0.022). Mean mastoid air-cell volume in the right side of otosclerosis patients was 6594.3 mm3 and it was not different from 6380.5 mm3 in the left side (p=0.445). Mean mastoid air-cell volume in normal side of TB fracture was 6477.2 mm3. The mastoid air-cell volume in the SCDS side was significantly smaller than that of otosclerosis and TB fracture patients (p=0.009, p=0.002, respectively). The mastoid air-cell volume in the normal side of SCDS was significantly smaller than that of TB fracture (p=0.019), but not significant with that of otosclerosis (p=0.063). CONCLUSIONS: Our findings revealed that the mastoid air-cell volume in the SCDS side was significantly smaller than control group, which suggest that the decreased mastoid pneumatization is closely related to the generation of SCDS.
Humans ; Mastoid ; Otosclerosis ; Semicircular Canals ; Temporal Bone

Osteoma is a benign bone-forming tumor which is most frequently found in the fronto-ethmoidal area. Although commonly discovered in the external auditory canal of the temporal bone, few cases have been reported in the mastoid or squamous portion of the temporal bone. The authors experienced a case of large osteoma that originated from the squama of temporal bone. We report this rare case and its successful management with a review of the literatures.
Ear Canal ; Mastoid ; Osteoma* ; Temporal Bone*

BACKGROUND AND OBJECTIVES: It is essential to understand gas physiology of mastoid cavity to study the pathophysiology of middle ear diseases, and the surface area and volume of mastoid mucosa are important parameters for evaluating gas physiology. However, the surface area and mastoid volume of the mastoid cavity have not been practically measured yet. Therefore, we measured and compared surface area and volume of the mastoid cavity before and after mastoidectomy using a virtual mastoidectomy model. SUBJECTS AND METHOD: We performed a virtual mastoidectomy using 10 cases of temporal bone CT indicating pneumatic mastoid. First, we removed all air cells after outlining with irregular AOI function after loading axial CT images to Image-Pro Plus 4.0. Then we filled the removed area with equal planes using local equalization filter. Finally, we calculated and compared the total surface area, volume and area to volume (A/V) ratio by estimating their circumference and area. RESULTS: The mean surface area of pneumatized mastoid cavity was 127.8 cm2 (range: 94.2-165.3 cm2), and the mean volume was 7.1 cm3 (range: 5.2-11.0 cm3). The mean surface area and volume were altered to 42.8 cm2 (range: 35.9-55.0 cm2) and 12.6 cm3 (range: 10.3-18.7 cm3), respectively, after virtual mastoidectomy. As a result, the A/V ratio decreased from 18 to 3.4 after a virtual mastoidectomy in the pneumatic mastoid cavity. CONCLUSION: When a complete mastoidectomy is performed in the pneumatic mastoid, the surface area is decreased by one third compared to a relatively minor increase in volume. Therefore, the surface area per unit volume is expected to greatly decrease after mastoidectomy. Some physiologic problems occurring after mastoidectomy could be more accurately explained using a virtual mastoidectomy model.
Ear, Middle ; Mastoid ; Mucous Membrane ; Temporal Bone

Vascular tinnitus, a sort of pulsatile tinnitus, should be differentiated with other sensorineural tinnitus because it is possible to be cured by correction of underlying systemic disease or surgery. The dehiscent high jugular bulb, a common cause of venous pulsatile tinnitus, can be cured by reconstruction of hypotympanum. We present a case of pulsatile tinnitus with dehiscent high jugular bulb which has been treated by surgery. Preoperative microscopic finding showed dark bluish pulsating mass in posteroinferior portion of tympanic membrane. Temporal bone CT showed high jugular bulb with bone defect of hypotympanum. The hypotympanum was reconstructed and high jugular bulb lowered using the harvested bony fragment from mastoid cortical bone. The pulsatile tinnitus disappeared immediately after surgery.
Mastoid ; Temporal Bone ; Tinnitus ; Tympanic Membrane

Osseointegrated prosthetic auricular reconstruction can be classified as either direct or indirect. In the Branemark system of direct osseointegration, implants are placed into the mastoid process of the temporal bone. In the Epitec system of indirect osseointegration, implants are inserted into a three-dimensional carrier plate that is fixed to the mastoid by means of screws. We experienced forty-four cases using the indirect system and seventeen cases using the direct system. We compared with two systems by complications, such as skin reaction, implant loosening, implant loss. There were no specific differences in the skin reaction around the implants and abutments in relation to age or system used. The degree of skin reaction was different according to the conditions around the implant: in cases of virgin microtia, a skin flap was used to cover the implant, in contrast to grafted skin coverage for failed autogenous reconstruction. In both systems, the skin reaction was more severe and frequent in skin flap than in grafted skin. Loosening of the implant was more frequent in the direct system; however, accidental detachment of the implant from the abutment was more frequent in the indirect system. To reduce complications of skin reaction in osseointegrated prosthetic auricular reconstruction, it is important for soft tissue around implant to immobilize. Therefore, grafted skin is better than skin flap as soft tissue around implant. And immobilization of soft tissue around implant by wound dressing is major facter.
Bandages ; Immobilization ; Mastoid ; Osseointegration* ; Skin ; Temporal Bone ; Transplants ; Wounds and Injuries