Determination of subcarinal angle of trachea using computed tomography

Background: Change in tracheal bifurcation angle (subcarinal angle) is an indirect marker of various cardiac, pulmonary and mediastinal pathologies. Helical computed tomography (CT) allows acquisition of volumetric set of data of the chest and can be used for accurate measurements of subcarinal angle using reconstructed images on a workstation using minimum intensity projection (MinIP).The objective of this study was to estimate normal subcarinal angle (SCA) of trachea by computed tomography and to assess its relationship with gender.Methods: This was an observational study comprising a study cohort of 552 patients comprising of 312 males and 240 females who were subjected to CT chest for various indications in our department. Patients with no underlying cardiac, mediastinal or pulmonary disease were included in the study. Spiral CT scan of chest was performed on 64-slice seimens CT SOMATOM and images were reconstructed with thickness of 1.5mm and the images were viewed in coronal reformatted minimum intensity projection (MinIP) for determination of subcarinal angle using the angle measuring tool provided in the workstationResults: The mean subcarinal angle (SCA) in males was (67.60±14.55). The mean subcarinal angle (SCA) in females was (78.90±11.04). Females had a higher mean SCA compared to males with a statistically significant difference (p-value <0.05).Conclusions: The mean SCA in females was higher compared to males with a statistically significant difference between the two. This study holds practical relevance with regard to the performance of invasive trachea-bronchial procedures like bronchoscopy and tracheal/bronchial intubation

Styloid Process: What Length Is Abnormal?

The length of the styloid process varies greatly in different populations and depends on ethnicity and geographical background. The elongated styloid process may be associated with Eagle’s syndrome. Therefore, the mean normal length of the styloid process in different population groups needs to be calculated and the upper cutoff limit for elongated styloid process should be found. The objective of the research was to evaluate the styloid process length in the Kashmiri population using multidetector computed tomography. Materials and Methods. We retrospectively evaluated 304 patients who underwent computed tomography of the head and paranasal sinuses, and the mean styloid process length was calculated on both sides. The mean of three measurements of styloid process length was taken. The study population was grouped as follows: Group I included patients at the age of 21-30 years; Group II comprised patients at the age of 31-40 years; Group III included 68 patients at the age of 41-50 years; Group IV comprised patients &gt; 50 years old. Results. The mean length of the styloid process in the studied population varied from 20 to 51 mm (mean 31.3 ± 4.5 mm). There was no significant difference in the length on both sides (p=0.835). The mean length of the styloid process was 30.1 ± 4.2 mm in females and 32.3 ± 4.8 mm in males (p&lt; 0.034). The lengths of the styloid process in different age groups were as follows: in Group I - 30.9 ± 4.4 mm; in Group II - 31.2 ± 4.8 mm; in Group III - 31.6 ± 4.3 mm; in Group IV - 31.5 ± 4.5 mm. Conclusions. The mean length of the styloid process in our population was higher as compared to many other ethnic groups. The styloid process in males was longer. The elongated styloid process on computed tomography scan should not be labeled as Eagle’s syndrome unless clinical symptoms are present

High resolution ultrasonography of thyroid nodules: can ultrasonographic assessment obviate the need for invasive aspiration cytology in ultrasonographically benign lesions?

The use of high-resolution ultrasound (HRUS) thyroid imaging has resulted in a significant revolution in the treatment of thyroid nodules. The enigma of thyroid nodules has been a blind spot for radiologists for a long period. Reporting a thyroid nodule as benign or malignant is quite difficult and many times not accurate. The American Collage of Radiology-Thyroid Imaging Reporting and Data System (ACR-TIRADS) 2017 classification has solved this problem to a large extent. However, the classification needed pathological confirmation for it to be highly accurate. We compared our HRUS-based TIRADS labeling of thyroid nodules with thyroid cytopathology using revised Bethesda classification system. Patients detected with thyroid nodules by HRUS were categorized using ACR-TIRADS and further were taken for fine needle aspiration cytology (FNAC) in our department. The pathological results were compared with the initial TIRADS category of the nodule and the effectiveness of the TIRADS classification in categorizing nodules into benign and malignant was assessed using various statistical variables. The initial USG and the FNAC were performed by a single radiologist with over 10 years of experience. A total of 201 patients underwent HRUS followed by FNAC after obtaining written consent in our department. The thyroid nodules labeled as true benign on ACR-TIRADS (TIRADS 2) were all true benign on Bethesda cytopathology (less than Bethesda III), confirming the high accuracy of HRUS. The diagnostic accuracy of HRUS in cases of ACR-TIRADS 3 nodules was approximately 90.6% with an error rate of 9.4%. Nodules labeled as ACR-TIRADS 4 and 5 had error rates of 47% and 10% in labeling nodules as malignant. The ultrasound-based ACR-TIRADS system can accurately predict the likelihood of specific nodules being benign. There is a strong concordance between Bethesda cytology and ACR-TIRADS classification, particularly for benign nodules. In resource-constrained system like ours, patients with TIRADS 2 and 3 nodules can be safely followed obviating the need for an invasive procedure like FNAC

Renal Artery Pseudo-aneurysms: Do All of Them Require Endovascular Management?

Purpose: Our study examines the etiological profile, clinical and imaging features of renal artery pseudo aneurysms (RAPs), as well as the efficacy and need for the angioembolization of RAPs in a resource-constrained setting. Materials and Methods: A total of 36 patients with RAPs were included in our study. Initial diagnosis was made by Doppler Ultrasonography (USG) followed by CT renal angiography in all cases. DSA was performed in 28 patients, as eight patients showed spontaneous resolution by thrombosis on immediate pre-procedure Doppler study. Angioembolization with a microcoil was performed for 30 aneurysms in 28 patients. Technical success was confirmed at the end of the procedure by a renal angiogram. To assess clinical success, we followed up with patients (with clinical and Doppler USG) for a period of six months. Results: The most common cause of RAPs in our study was percutaneous nephrolithotomy (PCNL), seen in 21 patients (58.3%), followed by trauma (25%), and partial nephrectomy (11%). All patients presented to us were within 21 days of the etiological event of hematuria or flank pain. USG was able to detect the RAP in 22 cases (61%). CT renal angiography was diagnostic in all patients but failed to demonstrate two additional aneurysms in one patient. RAP size ≤ 4 mm and absence of brisk filling on CT renal angiography was associated with spontaneous resolution in eight patients, probably an indication of the beginning of spontaneous thrombosis. Angioembolization was done using microcoils and showed 100% technical and clinical success. Conclusion: PCNL is the most common etiological factor for RAPs in our setting. Such patients should have a Doppler USG done prior to discharge from the hospital. CT angiographic flow dynamics (delayed peak enhancement) may be helpful in the identification of RAPs with a high probability of subsequent spontaneous resolution. Angiography followed by embolization using microcoils is the most effective and safe treatment for RAPs with no significant loss of renal parenchyma, although cost remains a limiting factor in our setting

Evaluation of various patient-, lesion-, and procedure-related factors on the occurrence of pneumothorax as a complication of CT-guided percutaneous transthoracic needle biopsy

Purpose: To assess the influence of various patient-, lesion-, and procedure-related variables on the occurrence of pneumothorax as a complication of CT-guided percutaneous transthoracic needle biopsy. Material and methods: In a total of 208 patients, 215 lung/mediastinal lesions (seven patients were biopsied twice) were sampled under CT guidance using coaxial biopsy set via percutaneous transthoracic approach. Incidence of post procedure pneumothorax was seen and the influence of various patient-, lesion-, and procedure-related variables on the frequency of pneumothorax with special emphasis on procedural factors like dwell time and needle-pleural angle was analysed. Results: Pneumothorax occurred in 25.12% (54/215) of patients. Increased incidence of pneumothorax had a statistically significant correlation with age of the patient (p = 0.0020), size (p = 0.0044) and depth (p = 0.0001) of the lesion, and needle-pleural angle (p = 0.0200). Gender of the patient (p = 0.7761), emphysema (p = 0.2724), site of the lesion (p = 0.9320), needle gauge (p = 0.7250), patient position (p = 0.9839), and dwell time (p = 0.9330) had no significant impact on the pneumothorax rate. Conclusions: This study demonstrated a significant effect of the age of the patient, size and depth of the lesion, and needle-pleural angle on the incidence of post-procedural pneumothorax. Emphysema as such had no effect on pneumothorax rate, but once pneumothorax occurred, emphysematous patients were more likely to be symptomatic, necessitating chest tube placement. Gender of the patient, site of the lesion, patient position during the procedure, and dwell time had no statistically significant relation with the frequency of post-procedural pneumothorax. Surprisingly, needle gauge had no significant effect on pneumothorax frequency, but due to the small sample size, non-randomisation, and bias in needle size selection as per lesion size, further studies are required to fully elucidate the causal relationship between needle size and post-procedural pneumothorax rate. The needle should be as perpendicular as possible to the pleura (needle-pleural angle close to 90°), to minimise the possibility of pneumothorax after percutaneous transthoracic needle biopsy

Imaging Evaluation of Mesenteric Ischemia: Is There a Golden Period for This Entity?

Background.The study was aimed at assessing the role of ultrasonography and multidetector computed tomography angiography in evaluating patients with suspected mesenteric ischemia, as well as assessing the effect of the time from presentation to management on mortality and morbidity. Materials and Methods. Patients with clinically suspected mesenteric ischemia underwent Doppler ultrasound and contrast-enhanced computed tomography. On ultrasonography, we assessed any filling defect in the superior mesenteric artery/vein, narrowing or occlusion of the proximal superior mesenteric artery, ascites, bowel wall thickening, and pneumatosis/portal venous gas. Computed tomography angiography was performed looking for any filling defect in the superior mesenteric artery/vein, superior mesenteric artery/vein calibre, bowel wall thickening, calibre and enhancement and pneumatosis/portal vein gas. Most of our patients underwent emergency surgery and the findings correlated with imaging. All the patients were divided into Group A (n=30) and Group B (n=17) based on the time from presentation to management: within 48 hours of presentation and 48 hours after presentation, respectively. Results. On computed tomography scan, mesenteric vascular involvement was seen in 27 (55%) patients, mesenteric/intestinal twist was observed in 12 (25%) patients, and non-occlusive mesenteric ischemia was found in 6% of patients. The computed tomography findings were found to have a sensitivity of 86%, a specificity of 94% and an accuracy of 90% in cases of mesenteric ischemia. Among 35 patients operated on, those presenting within 48 hours, had a significantly less mortality (63%) in comparison to those presenting after 48 hours (90%). Conclusions. Clinical, laboratory and ultrasound features are non-specific in diagnosing mesenteric ischemia. Computed tomography angiography is a sine qua non in mesenteric ischemia diagnosis. Patients with venous ischemia respond well to conservative management. Early intervention within the first 48 hours is associated with better prognosis

Computed Tomography Severity Grading of Chronic Obstructive Pulmonary Disease based on Volumetric Assessment of Inspiratory and Expiratory Scans

Background & Aims:  To determine attenuation threshold for detection and quantification of air trapping in obstructive airway disease. Quantify airway dysfunction in patients of obstructive airway disease & its correlation with pulmonary function tests. Materials & Methods: Paired HRCT scans of 48 patients were done and correlated with Pulmonary Function Tests taken within 2 weeks of the study. Threshold attenuation value on expiratory scan that signifies air trapping was obtained by correlating relative volumes with PFT parameters (PEF 25-75% & RV/TLC). The lung volumes at this threshold were then correlated with PFT values signifying airway dysfunction (FEV1, FEV1/FVC and PEF 25-75%) and airway dysfunction was then quantified based on these volumes. Results: Maximum correlation of PFT parameters signifying air trapping is with relative volume of limited lung at -850HU (l850) (p -10%). Conclusion: l850 can be used as a CT parameter to quantify airway dysfunction irrespective of presence or absence of emphysema. Severity classification of obstructive airway disease was formulated based on l850

Perinephric abscess caused by ruptured retrocecal appendix: MDCT demonstration

Acute appendicitis may occasionally become extraordinarily complicated and life threatening yet difficult to diagnose. One such presentation is described in a 60-year-old man who was brought to the hospital due to right lumbar pain and fever for the last 15 days. Ultrasonography showed a right perinephric gas and fluid collection. Abdominal computed tomography with multidetector-row CT (MDCT) revealed gas-containing abscess in the right retroperitoneal region involving the perinephric space, extending from the lower pole of the right kidney up to the bare area of the liver. Inflamed retrocecal appendix was seen on thick multiplanar reformat images with its tip at the lower extent of the abscess. Laparotomy and retroperitoneal exploration were performed immediately and a large volume of foul smelling pus was drained. A ruptured retrocecal appendix was confirmed as the cause of the abscess

Abdominal cocoon: Classic computed tomography images

Abdominal cocoon is an uncommon cause of acute or subacute intestinal obstruction mostly secondary to tuberculosis. This report highlights the classic imaging features on computed tomography in a case of ileocecal tuberculosis with secondary abdominal cocoon