Cetin Celenk

Bone Density Measurement Using Computed Tomography

Osteoporosis is a major medical, social, and economic problem. Osteoporosis and low bone mass affect an estimated 44 million Americans (National Osteoporosis Foundation, 2008). The lifetime risk of hip, spine, or forearm fractures is estimated to be 40% in white women and 13% in white men above 50 years of age. Considerable attention is therefore focused on assessing bone mass and the ability to identify people at risk of fracture. Determining bone density (BD) helps a doctor determine those at increased risk for osteoporosis-related fracture. Bone density (or bone mineral density) is a medical term that refers to the amount of matter per square centimeter of bone. Bone density is used in clinical medicine as an indirect indicator of osteoporosis and fracture risk. BD measurements are most commonly made over the lumbar spine and over the upper part of the hip. In recent literature, several approaches have been introduced to measure mandibular and skeletal BD, and then compare these measurements with BD in other parts of the skeleton. The measurement is painless, non-invasive, and involves minimal radiation exposure. In this chapter, bone density using computed the tomography technique will be introduced and discussed. CT is an imaging technique that shows human anatomy in cross sections and provides a three-dimensional dataset that can be used for image reconstruction and analysis in several planes or three-dimensional settings. CT is used to study bone pathology, from traumatic lesions to bone neoplasm. In addition to morphologic information, CT also provides information about tissue attenuation. Direct Hounsfield unit measurements for BD may be used to examine bone quality. Attenuation values can be extracted from raw CT data and used to reconstruct images. These values can also be used to estimate the density of tissues. CT accurately measures bone density. CT density measurement methods can be used as to separate the trabecular bone from the cortical shell and the posterior elements of vertebrae. CT density measurements have shown superiority to other modalities Using CT for take density measurements is discussed, including several of its challenges, in the current clinic. The foundations of CT density, classification, and registration are discussed in detail.

Postoperative Lung Volume Change Depending on the Resected Lobe

OBJECTIVES The aim of this study was to evaluate the lung volume changes depending on the resected lobes. The changes were quantitatively evaluated using stereological methods on computed tomography images and by pulmonary function tests (PFTs). METHODS The study subjects included 30 patients who underwent lung resection. Of these, 26 patients underwent lung resection due to non-small cell lung cancer and 4 patients for benign reasons. Patients were classified into the following six groups according to the resected lobes and lungs: right lower lobectomy, right upper lobectomy, left lower lobectomy, left upper lobectomy, right pneumonectomy, and left pneumonectomy cases. All patients were evaluated with the PFT and computed thorax tomography (CTT), preoperatively and in the postoperative 3rd month. Volume changes due to resection were estimated on CTT scans using the Cavalieri principle of the stereological methods, and their relationships to the PFTs were evaluated. RESULTS Stereologically estimated data showed that the volume loss was 19.01% in upper lobectomy and 5.57% in lower lobectomy (p < 0.05). The highest volumetric increase of the contralateral lung and minor volume loss of the ipsilateral lung was observed in lower lobectomy. After right lower lobectomy, the highest postoperative volume increase was observed at the contralateral lung and the least volume loss in the remaining ipsilateral lung. In PFT, forced vital capacity (FVC) decreased to 3.07% after lower lobectomy whereas it decreased to 11.94% after upper lobectomy. FVC revealed that no significant change occurred after right lower lobectomy (p < 0.05). CONCLUSIONS Although the parenchyma resected in lower lobectomy is larger, the postoperative total lung volume reduction is less than that of upper lobectomy. After lower lobectomy, postoperative compensation is achieved specifically by the expansion of contralateral lung, together with the remaining ipsilateral lung.

Paratracheal air cysts: Prevalence and correlation with lung diseases using multi-detector CT

The purpose of this study was to determine the prevalence of paratracheal air cysts (PACs), their correlation with different lung diseases and their connection with the trachea by chest multi detector computed tomography (MDCT).

Correlation between Depth of Myocardial Bridging and Coronary Angiography Findings

Background: Myocardial bridging (MB) is a congenital anomaly in which a segment of coronary artery is surrounded by myocardium. Purpose: To investigate the correlation between muscle thickness over the tunneled coronary artery (depth) in MB and the presence of milking effect (ME) and systolic narrowing ratio in catheter angiography (CA). Material and Methods: The records of 36 patients who underwent a coronary computed tomography angiography (CTA) and following CA examination for suspicious ischemic coronary artery disease, between March 2005 and September 2007, were retrospectively evaluated. According to the depth of MB on CTA, patients were grouped into four groups: group 1, <1 mm; group 2, 1– <2 mm; group 3, 2– <4 mm; group 4, ≥4 mm. The presence of milking effect, systolic narrowing ratio, and atherosclerotic stenosis at CA were recorded. CTA and CA results were then compared to evaluate the correlation. Results: In total, ME was found in 15 arteries at CA (42%). There was no ME in group 1; it was present in 11% of group 2, 67% of group 3, and 100% of group 4. Starting from group 3, the percentage of likelihood of seeing the milking effect was 77%, and the percentage of systolic narrowing was between 30 and 70%. There was a significant correlation between depth of MB and systolic narrowing (P<0.01), while no significant correlation between length of MB and systolic narrowing was found (P=0.32). In seven of the 36 patients (group 1, 0; group 2, 1; group 3, 3; group 4, 3), clinical findings were related to pure MB. Conclusion: The depth of MB is positively related to coronary narrowing and clinical ischemic findings.

Pulmonary alterations in Behcet's disease

PURPOSE This study aims to demonstrate pulmonary alterations (PA) in patients with Behcets disease by using CT. MATERIALS AND METHODS CTs of 50 patients with Behcets disease and 20 others in a control group have been evaluated retrospectively for PA (septal, reticular, nodular, atelectatic opacities). RESULTS Eight out of 50 patients (16%) with Behcets disease showed PA. Three out of 20 (15%) in the control group showed PA. No differences were observed between Behcets disease patients and the control group regarding pulmonary alterations (p=0.917). No differences were observed in the disease duration, ages and sex in either group in those with and without PA. CONCLUSION Pulmonary alterations can be seen in patients with Behcets disease, but these alterations are not significant.

Hereditary hemorrhagic telangiectasia associated with pulmonary arteriovenous malformations presenting as hemothorax.

A 51-year-old woman was admitted to emergency unit complaining of sudden onset chest pain. The patient had a family history of hereditary hemorrhagic telangiectasia. Thorax computed tomographic angiography demonstrated high-density left pleural effusion, and 3 giant arteriovenous malformations. Thoracentesis revealed hemorrhagic fluid. We present successful coil embolization of pulmonary arteriovenous malformations associated with hereditary hemorrhagic telangiectasia.

Evaluation by quantitative magnetic resonance imaging of trabecular bone quality in mandible and cervical vertebrae

OBJECTIVE The purpose of this study was to make a comparison between mandibular and cervical vertebral bone quality (BQ) using quantitative magnetic resonance imaging (MRI). METHODS The cervical MRI images included in this study belonged to 36 patients (23 women, 13 men; mean age 54 years) who had various clinical symptoms (e.g., headache, vertigo, imbalance). The mandible and cervical vertebrae BQ measurements were performed by the same investigator on these sections. Mandibular and cervical vertebral T2(*) axial cross sections were performed following receipt of consent from each patient. T2(*) relaxation time values were determined in the trabecular area. RESULTS The relationship between cervical vertebral and mandibular BQ was revealed by regression and correlation analysis. The correlation coefficient was r=0.04, r(2)=0.002, and P=0.818, which is not statistically significant. The relation between age and mandible BQ was very weak (r=0.001, r(2)=0.000001, and P=0.995), and the relation between age and cervical vertebrae BQ was correlated (r=-0.585, r(2)=0.342, and P<0.001). CONCLUSIONS There is a low correlation between the BQ measurements of cervical vertebrae and the mandible. Precise mandibular BQ measurement does not provide information that correlates with BQ in the other sites of the skeleton. Although an age-dependent decrease occurs in vertebral BQ, no significant alteration occurs in mandibular BQ.

Efficiency of B-mode Ultrasound and Strain Elastography in Differentiating Between Benign and Malignant Cervical Lymph Nodes

Purpose The purpose of this study was to evaluate the diagnostic accuracy and efficiency of ultrasonography (US), especially when combined with strain elastography (SE), in differentiating between benign and malignant cervical lymph nodes (LNs). Methods Forty-one LNs were examined by B-mode US, power Doppler US, and SE. The following imaging features were analyzed: shape, echogenicity, echogenic hilum, calcification, intranodal vascular pattern, elasticity scores (5 categories), and strain ratio. The average strain ratio was calculated as the mean strain of the adjacent sternocleidomastoid muscle divided by the mean strain of the target LN. The results of the US and SE features were compared with the histopathologic findings. Results The imaging features that were significantly associated with malignant LNs were an increased short-to-long axis diameter ratio, abnormal or absence of hilum, microcalcification, type 2-3-4 vascularity, 3-4-5 elasticity scores, and a high level of strain ratio (P < 0.05). The cutoff value of the strain index was detected as 1.18. According to this, there was a significant difference (P = 0.004) in the strain index between benign and malignant LNs. Conclusions Strain elastography is useful in differentiating between benign and malignant cervical LNs, thereby informing decisions to perform a biopsy and/or surgery, and facilitating follow-up.

Descending necrotizing mediastinitis associated with an infected dentigerous cyst

Descending necrotizing mediastinitis (DNM) is a rare condition in which an infection from the head and neck propagates into the mediastinum. The most common cause of DNM is odontogenic infection. DNM is spread by the fascial planes from the neck into the mediastinum and requires an aggressive surgical drainage through cervical and thoracic approaches. We report on a 67-year-old male patient, who had acute mediastinitis related to an infected dentigerous cyst in the left parasymphyseal region. A multidisciplinary team approach was used to treat the patient. The team consisted of thoracic surgeons, maxillofacial surgeons, and a radiologist. After the drainage of the mediastinum and pleural cavity, the cyst was enucleated. The patient was discharged at the 42nd day of hospitalization. The aim of this article is to present diagnosis, management, and follow-up of an infected dentigerous cyst that caused DNM.

Plasma cell granuloma of the mediastinum with secondary renal amyloidosis

To the Editor: Plasma cell granuloma (PCG) is the most common primary, tumor-like lesion of the lung in children although it can occur in various extrapulmonary locations such asmediastinum [1]. Although some authors consider PCG as a benign and static lesion with the possibility of spontaneous resolution [2], others suggest a more aggressive course with rapid growth and local invasiveness [3]. Secondary amyloidosis is a well-known cause of nephotic syndrome and renal failure, mostly occurring after inflammatory conditions and malignancies [4]. A 9-year-old girl was admitted to hospital with fatigue and loss of appetite for 3 months and a productive cough for a week. Physical examination revealed pallor, cachexia, decreased breath sounds on the right chest, distended abdomen with a hepatomegaly of 10 cm beyond costal margin, and splenomegaly. Chest X-ray demonstrated a large lobulated, well-defined mass in the right paramediastinal area with pleural fluid. Computed tomography (CT) of the thorax showed two contiguous large lobulated mass lesions on the paracardiac area; one 20 10 cm with calcification and the other 5 5 cm, located on the postero-basal and antero-basal areas, respectively. There was rightward deviation of the trachea and mediastinal structures (Fig. 1). Laboratory investigations revealed a hemoglobin of 8.4 g/dl, mean corpuscular volume (MCV) 65.4 fl, leucocyte count 9,300/mm with a normal differential, platelet count 648,000/mm, erythrocyte sedimentation rate (ESR) 55 mm/hr and normal serum biochemical studies. Pleural fluid examination revealed polymorphonuclear and mononuclear leucocytes, a protein of 2,990 mg/dl, glucose of 71 mg/dl and no malignant cells. Bone marrow aspiration showed no tumor infiltration. A trucut biopsy was performed and histological examination indicated a non-specific, inflammatory process with proliferating fibroblasts. She underwent right thoracotomy with excision of more than 70% of the huge mass, which was located at the posterior mediastinum. Complete tumor removal was not possible because of the close relation to vital organs. The lesion had variable cellularity and was composed of spindle cells arranged in hyaline stroma with scattered inflammatory cells on histopathological examination. Tumor cells stained positively for smooth muscle actin and negatively for S-100 using immunhistochemical staining; a diagnosis of PCG was made. On follow-up visits, the patient had cachexia and acute phase reactants were extremely high (CRP, 173 mg/dl and ESR, 110 mm/hr). Two courses of prednisone, 2 mg/kg/day for 6 weeks, were given after 4 and 9 months following the operation. She had massive proteinuria (160 mg/m/hr) 1 year after the operation. Abdominal ultrasound examination revealed bilaterally enlarged kidneys. Renal biopsy was performed, and upon detection of Congo red positive material diffusely accumulated in light microscopy sections, the diagnosis of amyloidosis was established. PCG is a difficult condition to diagnose preoperatively and is often only biopsied or incompletely excised at thoracotomy [5]. While complete excision is essential both for diagnosis and effective treatment [6], the close proximity of the lesion to the inferior vena cava made a complete excision impossible in our patient. Pharmacological courses of steroids postoperatively may be helpful to treat PCG, when total surgical resection of the tumor is not possible [7]. In secondary amyloidosis, the major infiltrative protein is the amino terminal end of serum