Sergin Akpek

Computed tomographic evaluation of surgically significant vascular variations related with the temporal bone

Variations of the vascular structures related with the temporal bone may cause important problems in diagnosis, treatment planning and surgery. High resolution computed tomography (CT) scans of 700 temporal bones of 350 patients were retrospectively examined for the incidence of dehiscent jugular bulb, high jugular bulb, diverticulum of jugular bulb, anteriorly located sigmoid sinus and dehiscent internal carotid artery. Dehiscent jugular bulb was seen in 27 (3.9%), high jugular bulb was seen in 142 (20.3%), jugular bulb diverticulum was seen in 55 cases (7.9%). The average distance between external acoustic canal and sigmoid sinus was found to be 13.3 mm and in 12.4% of the cases this distance was < 10 mm. Of 700 temporal bones, 10 (1.4%) showed dehiscent carotid canal. To aid diagnosis, treatment planning and surgery, CT scanning is currently a very reliable tool in determining these conditions. Special attention should be paid to the position of the vascular structures in the preoperative temporal bone CT scans.

Primary stenting for complex atherosclerotic plaques in aortic and iliac stenoses

AbstractPurpose: To evaluate the efficacy of primary stenting for complex atherosclerotic plaques in aortic and iliac stenoses that are not amenable to balloon angioplasty alone. Methods: Nineteen patients with complex atherosclerotic plaques were treated with a Palmaz stent (n=19), Wallstent (n=1), Strecker stent (n=1), or Memotherm stent (n=1). A total of 22 stenoses presenting with complex plaque morphology including ulcerated plaques, ulcerated plaques with focal aneurysms, plaques with heavy calcification, severely eccentric plaques, plaques with overhanging edge, and plaques with spontaneous dissection were stented. The lesions were in the aorta (n=1), common iliac artery (n=19), or external iliac artery (n=2). Results: Immediate angiography after stent placement revealed restoration of patency of the stented segment. Focal aneurysms and ulcerated areas were occluded in the follow-up angiographies obtained 4–12 weeks after the procedure. In one case with poor distal runoff and multiple complex lesions of the iliac artery, subacute occlusion occurred. Clinical and angiographic follow-up (3–46 months) revealed patency of all other stented segments. Conclusion: Primary stenting is an effective and reliable approach for complex plaques in stenoses. Patency of the arterial segment with a smooth lumen can be created without the risk of acute complications such as distal embolization, dissection, or occlusion.

Cost‐effectiveness of Computed Tomography in the Evaluation of Patients With Headache

We report a retrospective study to determine the cost‐effectiveness of cranial computed tomogrsphy in patients with headache without neurological finding. Five hundred ninety‐two neurologically normal patients were examined between 1990 and 1993 for the complaint of headache. Examination results were reevaluated from written report and image archive systems. Results were divided into three groups. In group P0, we included patients with normal cranialcomputed tomography findings. In group P1, patients showed some minor pathologies like ischemic or atrophic changes. These findings neither explained the reason for headache nor changed the clinical or therapeutic approach. The third group (P2) was to include patients with gross intracranial pathology like space‐occupying lesions or bleeding. Five hundred forty‐six of 592 patients were in the P0group (92%), and the remaining 46 patients were in the P1group (8%). No patient was found to have serious intracranial pathology detected by computed tomography. Cost of detection of a case with significant pathology was calculated. It is our opinion that computed tomography is an unrewarding technique in the evaluation of patients with chronic headache whose neurological examinations are normal.

Vascular Loops at the Cerebellopontine Angle: Is There a Correlation with Tinnitus?

BACKGROUND AND PURPOSE: Tinnitus is a common disorder, and the etiology remains mostly unclear. The purpose of this study was to investigate the causative effect of the vascular loop and compression of the vestibulocochlear nerve at the cerebellopontine angle in patients with unexplained tinnitus. MATERIALS AND METHODS: This study was approved by our institutional review board. Written informed consent was obtained from all participants. Fifty-eight patients with unexplained tinnitus and 44 age- and sex-matched asymptomatic controls were examined with temporal MR imaging. Besides the tinnitus and control groups, a third group was formed by asymptomatic sides of patients with unilateral tinnitus. A 3D fast imaging employing steady-state acquisition (3D-FIESTA) sequence was performed in addition to the regular pre- and postcontrast axial and coronal sequences. The anatomic type of vascular loop, the vascular contact, and the angulation of the vestibulocochlear nerve at the cerebellopontine angle (CPA) were evaluated by 2 experienced neuroradiologists. The χ2 test was used for statistical analysis. RESULTS: No statistically significant differences were found between the patient and control groups for the anatomic type of vascular loop, the vascular contact, and the angulation of the vestibulocochlear nerve at the CPA (P > .05). CONCLUSION: Although 3D-FIESTA MR imaging correctly shows the anatomic relationships of the vestibulocochlear nerve, its vascular compression cannot be attributed as an etiological factor for tinnitus.

Central nervous system aspergillosis: magnetic resonance imaging, diffusion-weighted imaging, and magnetic resonance spectroscopy features.

Aspergillus infection is invasive in nature in the immunosuppressed population and disseminates throughout the body, with the brain being a common site. Conventional magnetic resonance imaging (MRI) combined with diffusion-weighted imaging (DWI) and magnetic resonance spectroscopy (MRS) play a life-saving role in the early diagnosis and treatment monitoring of this potentially fatal infection. We present MRI, DWI, and MRS findings of a case of central nervous system aspergillosis with treatment follow-up.

Leontiasis ossea in a patient with hyperparathyroidism secondary to chronic renal failure.

Osteitis fibrosa describes the bone changes seen in renal osteodystrophy secondary to longstanding hyperparathyroidism. We report a 19-year-old man with longstanding chronic renal failure with a severe form of osteitis fibrosa affecting the jaws and other maxillofacial bones causing bizarre facial and dental deformity in a patient–uraemic leontiasis ossea.

Diffusion-weighted imaging of the appendicular skeleton with a non-Carr-Purcell-Meiboom-Gill single-shot fast spin-echo sequence.

OBJECTIVE The objective of our study was to prospectively evaluate the signal-to-noise ratio (SNR) improvement in diffusion-weighted imaging (DWI) of the appendicular skeleton with the use of a newly developed non-Carr-Purcell-Meiboom-Gill (non-CPMG) single-shot fast spin-echo (SSFSE) sequence and to evaluate its effect on apparent diffusion coefficient (ADC) measurements. SUBJECTS AND METHODS DWI of the bone was performed in 32 patients with an echo-planar imaging (EPI)-based sequence followed by a non-CPMG SSFSE technique. SNR and ADC values were measured over a lesion-free right femoral head. A score was assigned for each set of images to assess image quality. When a bone lesion was present, contrast-to-noise ratio (CNR) and ADC were also measured. Paired Students t tests were used for statistical analysis. RESULTS The mean (+/- SD) SNR values were 9.89 +/- 2.20 and 81.68 +/- 4.87 for EPI and non-CPMG SSFSE DWI, respectively. SNR values associated with the non-CPMG SSFSE technique were found to be significantly higher than those measured with the EPI-based DWI technique (p < 0.01). Mean ADCs of the bone were 0.57 +/- 0.20 and 0.29 +/- 0.15 x 10(-3) mm2/s, respectively, for EPI and non-CPMG SSFSE DWI. Image quality scores were higher for the non-CPMG SSFSE DWI technique (p < 0.05) than for the EPI-based DWI technique. Overall lesion CNR was found to be higher in DWI performed with the non-CPMG SSFSE technique. CONCLUSION The non-CPMG SSFSE technique provides a significant improvement over the currently used EPI-based DWI technique and has the potential to be a powerful tool in imaging the appendicular skeleton.

Postcatheterization Femoral Arteriovenous Fistulas: Endovascular Treatment with Stent-Grafts

AbstractPurpose: To report our results of stent-graft implantation for the endovascular treatment of postcatheterization femoral arteriovenous fistulas (AVFs) occurring between the deep femoral artery and the femoral vein. Methods: Endovascular treatment of iatrogenic femoral AVFs as a result of arterial puncture for coronary angiography and/or angioplasty was attempted in 10 cases. Balloon-expandable stent-grafts, one for each lesion, were used to repair the fistulas, which were between the deep femoral artery and the femoral vein in all cases. Stent-graft implantation to the deep femoral artery was performed by a contralateral retrograde approach. Results: All stent-grafts were deployed successfully. Complete closure of the fistulas was accomplished immediately in nine of 10 cases. In one case, complete closure could not be obtained but the fact that the complaint subsided was taken to indicate clinical success. In three cases, side branch occlusion of the deep femoral artery occurred. No complications were observed after implantation. Follow-up for 8–31 months (mean 18.5 months) with color Doppler ultrasonography revealed patency of the stented arterial segments without recurrent arteriovenous shunting in those nine patients who had successful immediate closure of their AVFs. Conclusion: Our results with a mean follow-up 18.5 months suggest that stent-graft implantation for the closure of postcatheterization femoral AVFs originating from the deep femoral artery is an effective, minimally invasive alternative procedure.

Familial Mediterranean fever mimicking septic arthritis: distinguishing with diffusion weighted imaging

FMF arthritis is generally monoarticular in origin. The affected joint is hot, tender, red and mimics septic arthritis. Conventional imaging findings, including magnetic resonance imaging (MRI) and ultrasound, do not help differentiate between these two entities. The final diagnosis depends on culture of the synovial fluid, and therefore initiation of proper drug therapy can be delayed. Diffusion weighted imaging (DWI), with its ability to detect altered water-proton mobility, might play an important role as a fast and non-invasive problem-solving tool in this setting. We here present MRI and DWI findings of a case of FMF arthritis mimicking septic arthritis.

Staging of hip avascular necrosis: is there a need for DWI?

Background No comprehensive study has been performed to stage avascular necrosis of the hip using diffusion-weighted imaging (DWI). Purpose To determine apparent diffusion co-efficient (ADC) alterations in hip avascular necrosis (AVN) and to determine variations of ADC values according to stages of disease. Material and Methods The study is approved by our institutional review board and local ethical committee. Written informed consent was present for each subject. Thirty-five femoral heads of 21 cases affected by AVN were included in the study. Control group consisted of both femoral heads of 10 healthy volunteers. The hips affected by AVN were staged according to Ficat and Arlet classification system from I to IV. All cases underwent to routine hip magnetic resonance imaging (MRI) and DWI performed with a single-shot fast spin echo sequence at a b value of 600 s/mm2. The ADC values were calculated automatically by placing ROIs on AVN lesions in affected patients and both femoral heads of control group. The median ADC value obtained from femoral heads of control group and that from AVN lesions were compared by Mann-Whitney U test. The median ADC values of AVN lesions at different stages were compared by Kruskal-Wallis test. Results The median ADC value of normal bone measured in control group was 185.5 ± 133.2 x 10−6 mm2/s. The median ADC value measured in hip avascular necrosis lesions was 988.0 ± 332.7 x 10−6 mm2/s. ADC values in hip AVN lesions were statistically significantly higher than normal bone marrow (P < 0.01). The median ADC values of hips with avascular necrosis at stage I, II, III, IV were 817.5 ± 172.1 x 10−6 mm2/s, 902.0 ± 181.0 x 10−6 mm2/s, 1200.0 ± 363.2 x 10−6 mm2/s and 1024.0 ± 324.0 x 10−6 mm2/s, respectively. There was no statistically significant difference among AVN lesions at stages I, II, III and IV (P > 0.05). Conclusion Although DWI is a promising imaging tool that provides valuable diagnostic information in hip AVN, it fails to distinguish between different stages, and therefore is of limited value.