Evaluation of image quality and radiation dose in computed tomography urography following tube voltage optimisation

INTRODUCTION

Computed tomography urography (CTU) comprehensively evaluates the urinary tract. However, the procedure is associated with a high radiation dose due to multiple scan series and therefore requires optimisation. The study performed CTU protocol optimisation based on a reduction in tube voltage (kV) using quality assurance (QA) phantom and clinical images and evaluated image quality and radiation dose.

METHODS

The study was prospectively conducted on patients referred for CTU. The patients were grouped into A and B and were scanned with the standard protocol, a protocol used for the routine CTU at the CT centre before optimisation, and optimised protocol, a protocol with reduced kV respectively. The protocols were first tried on a quality assurance (QA) phantom before being applied to patients, and image quality was assessed based on signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR). In addition, the clinical images were assessed based on the visibility of the anatomical criteria for CT images by five observers with >5 years of experience. The data were analysed using both visual grading characteristic (VGC) curves and statistical package for social sciences (SPSS) version 22.0.

RESULTS

The dose was significantly lower in the optimised protocol with a 10 % reduction in both volume computed tomography dose index and (CTDIvol) and dose length product (DLP) for the phantom images, and a 26 % reduction in CTDIvol and 28 % in DLP for the clinical images. However, there was no significant difference in image quality noted between the standard and optimised protocols based on the quantitative and qualitative image quality evaluation using both the QA phantom and clinical images.

CONCLUSION

The findings revealed a significant dose reduction in the optimised protocol. Further, image quality in standard and optimised protocols did not differ significantly based on quantitative and qualitative methods.

IMPLICATION FOR PRACTICE

kV optimisation in contrast-enhanced procedures provides dose reduction and should be encouraged in the medical imaging departments.

Knowledge of computed tomography dose optimisation and justification among CT users and referring physicians: A single hospital study

INTRODUCTION

Radiation dose associated with computed tomography (CT) remains a concern, and radiation risk does not receive the needed attention, especially in low and middle-income countries. This because the frequency of this high-dose examination is rapidly growing and systems for protocol optimisation and dose justification are yet to be provided in CT imaging.

OBJECTIVE

To determine radiographers' and radiologists' awareness and knowledge of CT dose optimisation. We also determined knowledge of dose justification and use of the referral guidelines amongst the referring physicians.

METHODS

Radiographers and radiologists were invited to complete a web-based questionnaire whilst the referring physicians completed a self-administered questionnaire. The returned questionnaires were analysed and a significant difference was determined using Yates corrected Chi-square, and a p-value of 0.05 was considered at the 95% confidence interval.

RESULTS

The response rates were 50% (17 out 34) and 35% (16 out 46) for radiographers and radiologists respectively while referring physicians had a response rate of 84% (92 out of 110). Overall, more radiographers (47.1%) than radiologists (18.8%) had good knowledge of CT doses and image quality, however, the difference in knowledge was not found to be significant (p = 0.167). In addition, knowledge of diagnostic reference levels (DRLs) was significantly (p = 0.033) higher amongst radiographers (52.9%) as compared to radiologists (12.5%). Meanwhile, physicians understood the principles of dose justification. However, their knowledge of referral guidelines was limited.

CONCLUSION

The study revealed that radiographers were more knowledgeable on matters relating to radiation dose and image quality as well as DRLs when compared to radiologists. Meanwhile, the concept of dose justification was understood among physicians, however, they had limited awareness and knowledge of referral guidelines.

Burden, Severity and Characteristic Pattern of Coronary Artery Disease using 160-Slice Computed Tomographic Angiography: Earliest Report from Northern Nigeria

BACKGROUND

Coronary computed tomography angiography (CCTA) allows for non-invasive visualization of the coronary arteries which is promising in diagnosing coronary artery disease.

OBJECTIVES

To determine the prevalence, morphology, anatomic distribution pattern and correlates of CAD in our environment.

METHODS

This cross-sectional study was conducted on the first cohort of patients referred for CCTA in our hospital. The patients were examined with 160-slice Toshiba® CT scanner. Their demographic data, relevant clinical information as well as the findings on CCTA were extracted and documented. The data were analysed using the R programming software version 4.0.4.

RESULTS

Out of a total of 153 patients who presented for CCTA within the study period, 133 (84.7%) were eligible for analysis. Their age ranged from 22-78 years with a mean ± SD of 55.8 ± 11.7 years. A total of 33 (24.8%) had normal CCTA, while 100 (75.2%) had either stenosis or total occlusion. There was a significantly higher (p-value of 0.00001) calcium score among those with stenosis compared to those with normal CCTA. The severity of the stenotic lesion was associated with the calcium score. The logistic regression analyses showed a statistically significant (P = 0.0415, OR = 1.0569, 97.5% CI =1.078152-1.123240) association between age and the presence of coronary stenosis. In addition, most of the stenotic lesions were in the left anterior descending artery (LAD).

CONCLUSION

Majority of the patients had coronary artery disease of variable severity and the LAD was the most involved artery. There was no significant association between sex and severity of the disease; however, old age and higher number of lesions were associated with severe disease.

FIRST CARDIAC COMPUTED TOMOGRAPHY TYPICAL RADIATION DOSE VALUES FROM A SINGLE CENTRE IN NIGERIA: A PILOT STUDY

Concern regarding radiation dose associated with cardiac computed tomography (CT) still exists and requires the use of diagnostic reference levels for dose optimisation. Typical median doses were established for 58 consented adult patients from a single centre for coronary artery calcium score (CACS) as volume computed tomography dose index (CTDIvol): 5.9 mGy; dose length product (DLP): 86.6 mGy*cm and cardiac CT angiography (CCTA) as CTDIvol: 11.1 mGy; DLP: 190.8 mGy*cm. Wide radiation dose variability in terms of CTDIvol was noted for CACS: 2.7-15.9 mGy, a 6-fold, whereas for CCTA it ranges from 3.8 to 52.8 mGy, a 14-fold. The DLP values for CACS range from 33.2 to 344.2 mGy*cm, which is 10-fold, whereas for CCTA it ranges from 32.8 to 834.9 mGy*cm, a 25-fold. The typical values compared lower than the radiation dose from other countries; however, the wide variability in dose remains a call for concern.

Predictive value of doppler cerebroplacental ratio for adverse perinatal outcomes in postdate pregnancies in Northwestern Nigeria

Background

Postdate pregnancy is a very common obstetric condition, increasing the risk of perinatal morbidity and mortality from uteroplacental insufficiency.

Aim

To determine the predictive values of Doppler cerebroplacental ratio (CPR), that is, the ratio between middle cerebral artery (MCA) and UA pulsatility indices (UA PI), and other potential velocimetric predictors of adverse perinatal outcomes in women with postdated pregnancies.

Patients and Methods

A prospective cohort study was conducted on consenting 212 low-risk pregnant women beyond 40 weeks' gestational age. The pulsatility indices of MCA, UA, and CPR as well as non-stress tests (NST) and amniotic fluid index (AFI) were measured and recorded. The women were divided into two groups based on the presence or absence of adverse perinatal outcome defined as: meconium stained liquor, meconium aspiration syndrome, perinatal asphyxia, cesarean section for suspected fetal distress, and perinatal death.

Results

: Of the 200 women whose data were available for analysis, 40 (20%) of them had adverse perinatal outcome and 160 (80%) had normal perinatal outcome. The CPR showed statistically significant difference in predicting adverse perinatal outcome (P < 0.001). CPR had a better predictive value than UA-PI and outperformed MCA-PI and NST for adverse perinatal outcomes. The sensitivity, specificity, negative predictive value (NPV), and accuracy of prediction of adverse perinatal outcomes by CPR were 90%, 81.25%, 97.01%, and 83%, respectively.

Conclusion

The Doppler CPR shows the highest diagnostic accuracy in prediction of adverse perinatal outcome in pregnant women after 40 weeks' gestation than UA PI and velocimetric indices when used as stand-alone test.

[Bilateral parotid'primary tuberculosis,a case study]

We report a case of bilateral Primary tuberculosis of the parotid gland that evolve more than one year, in a 35 years old patient, without any pathologic antecedent, where physical examination showed bilateral parotid swelling, in a context of conservation of general state. Ultrasound showed parotids increased in volume, heterogeneous with many fluid tissue formations, whose largest voluminous at right measure 28 millimeters, against 25 millimeters at left, with necrosis areas. The scan showed homogenous tissue density lesions, enhanced after contrast product injection. The fine needle aspiration was in favor of granulomatous lymphadenitis, suggestive of tuberculosis. Intradermoreaction to tuberculin was positive (15 millimeters in diameter).

The diagnosis of bilateral primary tuberculosis of the parotid was retained. A 6 months antituberculosis medical treatment was established with disappearance of parotid swelling, without recidive or others complications, on a decline of 14 months after treatment.

An unusual cause of Lemierre Syndrome

Lemierre syndrome is a rare, grave and life-threatening disease characterized by a septic thrombophlebitis of the internal jugular vein. Fusobacterium necrophorum is the most causative germ but sometimes others germs can be responsible. The authors report the first published case of Lemierre syndrome caused by a coinfection Levinea sp - Mycobacterium tuberculosis.

INJURIES OF BOKO HARAM INSURGENCY IN SOUTH-EAST NIGER REPUBLIC

BACKGROUND

Currently, wounds of wars, terrorism and criminality are increasing and constitute major public health problem worldwide.

AIM

To present the epidemiological, clinical and therapeutic characteristics of the wounds observed during the Boko Haram (BH) insurgency in the South-east of the Republic of Niger.

METHODOLOGY

This was a cross-sectional study from December 2014 to December 2016 at Diffa Regional Hospital, Diffa, Niger of individuals whose injuries were as a result of Boko Haram insurgency.

RESULTS

In the period of this study, 573 injuries from Boko Haram insurgency were managed at the Regional Hospital at Diffa. The majority, 513(89.5%), were males while females constituted 60(10.5%) with a male/female ratio of 8.55. The mean age was 30,94(SD24,91) years (range 1 to 97 years). Civilian victims accounted for 379 (66.1%) while Nigerien soldiers accounted for 160(27.9%) and 34 (5.9%) were Boko Haram fighters. Firearms and explosives accounted for injuries in 489 (85.3%) and 7(1.2%) of patients respectively; 42 (7.3%) suffered injuries from a variety of traditional weapons. Injuries to limbs accounted for 361(63%) of cases and polytrauma in 65(11.34%). The main surgical management included wound debridement in 409 (71.4%), external bone fixation in 38 (6.6%), laparotomy in 30 (5.2%), thoracic drainage in 27 (4.7%), and major limb amputations in 13 (2.3%) cases.Postoperative follow-up was uneventful in 460 (80.28%) of cases; there were 29 deaths, giving a mortality rate of 5.1%. Predictors of death after injuries of Boko Haram terrorism in this study included: being civilian patients (OR = 3.38 [1.15-9.85], p=0.018), injuries to head, neck, trunk or spine (OR 3.45[1.58-7.58], p= 0.001) or the presence of polytrauma on admission (OR = 17.30 [7.72-38.80], p<0.0001).

CONCLUSION

This study has shown that injuries sustained in Boko Haram insurgency in Niger were mainly firearm injuries and injuries from the use of traditional weapons, affecting mostly young civilian males. The part of the body most commonly involved were the extremities, with mainly soft tissue injuries. Wound debridement was the commonest surgical procedure performed and the mortality rate was 5.1%. Predictors of mortality were being civilian patients, injuries of head, neck, trunk or spine and polytrauma. The ICRC has played a major role in strengthening our hospital for the task of caring for the victims, in terms of provision of material resources and in the further training of our personnel.

Computed tomography dose index for head CT in northern Nigeria

Computed tomography dose index w and dose length product were recorded for the purpose of developing diagnostic reference levels (DRLs) for radiation dose optimisation. The study was conducted in three radiology departments with CT centres in Northern Nigeria. Data were collected from 54 consenting adult participants (weighing 70 kg ± 3) that had head CT scans. Analysis was done using SPSS version statistical software. A combined dose for the three centres was calculated and compared with the reported data from the international communities where there are established DRLs. Third quartile values of CTDIw and DLP were determined as 77 mGy and 985 mGy cm, respectively. Local DRLs that are significantly higher than most of the reported data in the literature have been established.