Comprehension of Cochlear Duct Length for Incomplete Partition Types.

OBJECTIVE: Preoperative assessment of the cochlear duct length (CDL) and cochlear dimensions allows the selection of optimized implants. We aimed to evaluate the CDL measurements in incomplete partition (IP) defect patients and to create a reference to the literature. METHODS: Forty-one patients with IP (13 IP I, 23 IP II, and 5 IP III) and 30 controls were included in the study. The standardized cochlear image showing the basal turn in the most expansive plane was reconstructed from temporal high-resolution computed tomography images. Cochlear duct length measured manually (CDL-M) was measured by points placed consecutively on the lateral wall of the cochlea. The defined equations for estimating CDL (CDL measured according to Schurzig et al formula [CDL-Ɵ], CDL measured according to Escudé et al formula [CDL-E], CDL measured according to Alexiades et al formula [CDL-A]) were calculated from the same images. Cochlear duct length mean values obtained by each method were compared for each IP type. RESULTS: The longest CDL value was found in the control group, irrespective of the calculation method. Incomplete partition II cases had the most extended mean CDL among IP types. Incomplete partition III had the shortest CDL among all groups' CDL-M values. However, the mean CDL-M values of IP types I and III showed close results. There was no significant difference between the CDL-E and CDL-M values of the control group. Similarly, no significant difference was found between CDL-Ɵ and CDL-M values in IP type III cases. However, the results of other estimating formulations of all groups differed significantly from CDL-M values. CONCLUSION: Cochlear duct length differences were detected between the control group and IP subtypes. These differences should be considered when choosing the appropriate electrode length. Because the results of formulas estimating CDL may differ from CDL-M in both control and IP cases, it would be more appropriate to use manual measurements in clinical practice.

Percutaneous treatment of simple renal cysts with 24-h-interval ethanol sclerotherapy.

Objective: To investigate the efficacy of 24-h interval multiple-session ethanol sclerotherapy for the treatment of simple renal cysts. Materials and Methods: The study sample included 58 patients (mean age, 65.37 ± 11.95 years). We included 76 simple renal cysts that were treated with percutaneous aspiration with a minimum of two sessions of 95% ethanol sclerotherapy in a 24-h interval between sessions. Patients were evaluated at 1, 3, and 6 months after the intervention for the efficacy of the treatment. Treatment success was defined as a complete regression of a cyst or a > 50% reduction in its volume, with no recurrence of symptoms. Results: The mean preprocedural cyst size was 72.98 ± 25.14 mm, and the mean preprocedural cyst volume was 205.76 ± 244.15 mL. The mean volume of ethanol used in the first sclerotherapy session was 62.76 ± 30.71 mL. The mean fluid accumulation in the cysts at the end of the first 24-h interval was 4.66 ± 7.13 mL. The mean quantity of ethanol used in the second sclerotherapy session was 26.48 ± 22.2 mL. A third sclerotherapy session was required in only 10 (13.2%) of the cysts. The mean follow-up period was 52.84 ± 37.83 months. The rate of complete regression was 97.4% for the whole sample at the end of the follow-up. Conclusion: Ethanol ablation with 24-h intervals is a safe and effective treatment option in the minimally invasive percutaneous treatment of simple renal cysts.

Objetivo: Demonstrar a eficácia da escleroterapia com etanol em sessões múltiplas em intervalos de 24 horas no tratamento de cistos renais simples. Materiais e Métodos: Foram avaliados 76 cistos renais simples de 58 pacientes (média de idade: 65,37 ± 11,95 anos) submetidos a aspiração percutânea e ao menos duas sessões de escleroterapia com etanol 95% num intervalo de 24 horas. Considerou- se sucesso de tratamento a regressão completa ou uma redução > 50% do volume do cisto, sem recorrência dos sintomas. Os pacientes foram reavaliados 1, 3 e 6 meses após o procedimento. Resultados: Antes do procedimento, a média do tamanho dos cistos foi de 72,98 ± 25,14 mm e a média do volume dos cistos foi de 205,76 ± 244,15 mL. A quantidade média de etanol utilizada na primeira sessão de escleroterapia foi de 62,76 ± 30,71 mL. A média de acúmulo de líquido ao final do intervalo de 24 horas foi de 4,66 ± 7,13 mL, sendo utilizada uma média de quantidade de etanol de 26,48 ± 22,2 mL na segunda sessão de escleroterapia. Uma terceira sessão de escleroterapia foi necessária em apenas 10 (13,2%) dos cistos. Na amostra geral, a taxa de regressão completa foi de 97,4%. O tempo médio de seguimento foi de 52,84 ± 37,83 meses. Conclusão: A ablação com etanol em intervalo de 24 horas é uma opção de tratamento segura, eficaz e minimamente invasiva no tratamento percutâneo de cistos renais simples.

Percutaneous treatment of simple renal cysts with 24-h-interval ethanol sclerotherapy / Tratamento percutâneo de cistos renais simples por escleroterapia com etanol em intervalo de 24 horas

Abstract Objective: To investigate the efficacy of 24-h interval multiple-session ethanol sclerotherapy for the treatment of simple renal cysts. Materials and Methods: The study sample included 58 patients (mean age, 65.37 ± 11.95 years). We included 76 simple renal cysts that were treated with percutaneous aspiration with a minimum of two sessions of 95% ethanol sclerotherapy in a 24-h interval between sessions. Patients were evaluated at 1, 3, and 6 months after the intervention for the efficacy of the treatment. Treatment success was defined as a complete regression of a cyst or a > 50% reduction in its volume, with no recurrence of symptoms. Results: The mean preprocedural cyst size was 72.98 ± 25.14 mm, and the mean preprocedural cyst volume was 205.76 ± 244.15 mL. The mean volume of ethanol used in the first sclerotherapy session was 62.76 ± 30.71 mL. The mean fluid accumulation in the cysts at the end of the first 24-h interval was 4.66 ± 7.13 mL. The mean quantity of ethanol used in the second sclerotherapy session was 26.48 ± 22.2 mL. A third sclerotherapy session was required in only 10 (13.2%) of the cysts. The mean follow-up period was 52.84 ± 37.83 months. The rate of complete regression was 97.4% for the whole sample at the end of the follow-up. Conclusion: Ethanol ablation with 24-h intervals is a safe and effective treatment option in the minimally invasive percutaneous treatment of simple renal cysts.

Resumo Objetivo: Demonstrar a eficácia da escleroterapia com etanol em sessões múltiplas em intervalos de 24 horas no tratamento de cistos renais simples. Materiais e Métodos: Foram avaliados 76 cistos renais simples de 58 pacientes (média de idade: 65,37 ± 11,95 anos) submetidos a aspiração percutânea e ao menos duas sessões de escleroterapia com etanol 95% num intervalo de 24 horas. Considerou- se sucesso de tratamento a regressão completa ou uma redução > 50% do volume do cisto, sem recorrência dos sintomas. Os pacientes foram reavaliados 1, 3 e 6 meses após o procedimento. Resultados: Antes do procedimento, a média do tamanho dos cistos foi de 72,98 ± 25,14 mm e a média do volume dos cistos foi de 205,76 ± 244,15 mL. A quantidade média de etanol utilizada na primeira sessão de escleroterapia foi de 62,76 ± 30,71 mL. A média de acúmulo de líquido ao final do intervalo de 24 horas foi de 4,66 ± 7,13 mL, sendo utilizada uma média de quantidade de etanol de 26,48 ± 22,2 mL na segunda sessão de escleroterapia. Uma terceira sessão de escleroterapia foi necessária em apenas 10 (13,2%) dos cistos. Na amostra geral, a taxa de regressão completa foi de 97,4%. O tempo médio de seguimento foi de 52,84 ± 37,83 meses. Conclusão: A ablação com etanol em intervalo de 24 horas é uma opção de tratamento segura, eficaz e minimamente invasiva no tratamento percutâneo de cistos renais simples.

Uncooled microwave ablation of osteoid osteoma: New approaches to an old problem.

OBJECTIVE: This study aims to evaluate the technical and clinical success of uncooled microwave ablation (MWA) in the treatment of osteoid osteoma with two-dimensional fluoroscopy guidance in the operating room. METHODS: The clinical and imaging data of 9 patients were retrospectively evaluated. Mean patient age was 14.55 years. The mean size and volume of the lesions were 17.2 × 10.8 × 8.0 mm and the mean nidus size was 6.86±2.05 mm on computed tomography. MWA was performed with uncooled probe in operating room and in sterile conditions. Numerical pain score was recorded before the procedure, the day after, and at 1, 3 months after the procedure. RESULTS: Clinical and technical success was achieved in 100% of patients. The mean volume of MWA-induced necrosis was 20.8 × 12.8 × 10.7 mm, peripheral scar thickness was 3.5±0.75 mm, and none of the patients had nidus enhancement on first month follow-up magnetic resonance imaging. Fluoroscopic guidance was conducted under digital c-arm. Patients received four to 12 spot films (mean: 6.6 kVp, 2.66 mAs) over the lower extremity. Mean radiation exposure to the skin due to imaging was 0.02 mGy per patient per procedure. The dose area product-the total amount of radiation deliverable to the patient was 0.75±0.32 Gy.cm2. CONCLUSION: This study demonstrated the effectiveness and the safety of the uncooled MWA in osteoid osteoma. The technique may effectively be used in operating room under c-arm fluoroscopy. Such hybrid approach may ensure sterility, anesthetic safety, and lower radiation dose to patients.

Efficacy and safety of percutaneous endobilliary radiofrequency ablation with a novel temperature-controlled catheter in malignant biliary strictures.

Purpose: The purpose of this study is to evaluate the efficacy and safety of temperature-controlled endobilliary radio-frequency ablation (EB-RFA) followed by metal stent placement for nonresectable malignant biliary strictures. Material and methods: From May 2017 to March 2021, 18 patients with malignant biliary obstruction who had undergone percutaneous EB-RFA and stent placement (n = 9) or stent placement only (n = 9) were included in this retrospective study. Outcomes were stent patency, technical and clinical success, overall survival, and 30-day complication rate. Kaplan-Meier and Cox regression analyses were performed to examine the relationship of EB-RFA with stent patency and overall survival. Results: The clinical and technical success rate for each group was 100%. The median stent patency was 128 days (95% CI: 122.2-133.8) in the EB-RFA group and 86 days (95% CI: 1.2-170.7) in the control group. It was significantly longer in the study group (p = 0.012). The mean overall survival was 267.7 ± 68.5 days (95% CI: 133.3-402.2) in the study group and 239.6 ± 33.9 days (95% CI: 173.1-306.2) in the control group. Log-rank test showed there was not a statistically significant difference in overall survival rates (p = 0.302). There were no major complications and no statistically significant difference in cholangitis rates (p = 0.620). Conclusions: Percutaneous temperature-controlled EB-RFA combined with biliary stent placement for malignant biliary obstruction can be safe and feasible, and effectively increase stent patency.

Uncooled Microwave Ablation as a Treatment Option to Preserve Thyroid Function in Patients with Benign Thyroid Nodules.

Objective: The objective is to evaluate the long-term efficacy and safety of uncooled MWA for the treatment of benign thyroid nodules and its long-term effect on thyroid functions. Material and Methods: The study was conducted on 40 patients with 40 nodules. They were treated between September 2019 and December 2020. Nodules' volumes, thyroid functions (triiodothyronine, free thyroxine, thyrotropin) and anti-thyroid peroxidase and anti-thyroglobulin antibodies were measured before treatment and at 3rd, 6th and 12th month following the treatment. Volume reduction rates and changes in clinical findings were evaluated. Results: The mean volume reduction rate was 49.88, 65.3, and 79.06% at 3rd, 6th, and 12th month, respectively. Antibody levels and thyroid function tests have remained within normal limits and were not exhibited significant change during follow-ups (p > 0.05), except for a significant increase in free thyroxin level at 12th-month (p = 0.007). Subjective symptoms and cosmetic scores were significantly improved all follow-up (p < 0.0001). The only complication was a first-degree skin burn in a patient. Conclusion: In conclusion, uncooled microwave ablation is an effective and safe method for the treatment of benign thyroid nodules and preserves thyroid function.

Minimally Invasive Excision of Breast Masses under Ultrasound Guidance: A Single Center's Five-Year Experience on the Breast Lesion Excision System.

Background: The purpose of this study was to investigate the feasibility of the percutaneous radiofrequency (RF) excision system (BLES) as a primary method of diagnosis and removal of small breast masses. Methods: Ninety-six lesions in 95 patients with 50.5 ± 8.4 years of age were treated in a five-year period by a single operator. Inclusion criteria were as follows: size (<20 mm), depth (>10 mm), and indeterminate or suspicious radiological features (74 BI-RADS 3 and 22 BI-RADS 4). The procedure was performed under ultrasound (US) guidance using 6 G retriever probes with 12-, 15-, and 20-mm baskets. Results: Lesions were between 5 and 20 (12.3 ± 3.8) mm in length. They were removed at the first attempt in all but one case. The technical success rate was 98.95%, and the diagnostic success rate was 100%. Ninety-one lesions were histologically benign and five were neoplastic. Two lesions that were previously classified as BI-RADS 3 were diagnosed as neoplasia (atypical lobular hyperplasia), and nineteen lesions that were previously classified as BI-RADS 4a were diagnosed as benign. The complete excision rate (presence of tumor-free negative surgical margin) was 40% in neoplastic lesions. There were no major complications. The minor complication rate was 1.58%. No recurrence was observed during 18 months of follow-up. Conclusion: BLES delivers surgical quality specimens for confident histopathological examination and is a safe alternative to surgical resection in lesions with suitable size.

Artery-first microwave ablation in the treatment of benign thyroid nodules.

BACKGROUND: Microwave ablation (MWA) is a safe and effective procedure for the treatment of benign thyroid nodules. The MWA causes progressive nodule shrinkage as well as the improvement of the symptoms and cosmesis. Some basic techniques have been described to further increase the efficacy and safety of this procedure. OBJECTIVES: To evaluate the efficacy of artery-first MWA as an advanced technique in the treatment of benign thyroid nodules. MATERIAL AND METHODS: A total of 40 patients treated with MWA were enrolled in the study. Nineteen patients who underwent artery-first MWA were selected for the study group and 21 patients who underwent MWA alone were included in the control group. Nodular vascularization was assessed using a new Doppler technique (Superb Microvascular Imaging (SMI)) and characterized using a 3-point scale. All patients were evaluated in terms of volume, symptoms, cosmetic scores, and laboratory findings before the procedure as well as 3 months (early-term follow-up) and 6 months (intermediate-term follow-up) after the procedure. RESULTS: Both groups were comparable with respect to the baseline volume (p = 0.135). Nevertheless, the nodular volume reduction rate was significantly different at 3-month follow-up (study group: 56.97 ±11.39%, control group: 47.07 ±7.93%; p = 0.003) and 6-month follow-up (study group: 78.38 ±8.91%, control group: 69.54 ±9.41%; p = 0.004). In both groups, cosmetic and symptom scores decreased progressively (p < 0.005) and there were no major complications. Thyroid hormones and antibodies were within normal limits before the procedure, and no significant change was observed during follow-up after the ablation. CONCLUSIONS: The artery-first MWA technique can be used in the treatment of benign thyroid nodules as a method of increasing the effectiveness of MWA.

Percutaneous catheter drainage in retroperitoneal abscesses: a single centre's 8-year experience.

Purpose: We have investigated the technical and clinical success of percutaneous catheter drainage (PCD) in retroperitoneal abscesses and factors that may affect the outcome. Material and methods: The study cohort included 45 patients (17 females and 29 males, with mean age of 56.3 years) that were treated between 2012 and 2020. Forty-seven abscesses were managed with PCD under ultrasonography, computed tomography, or fluoroscopy guidance. Patients' demographics, lesion locations, predisposing factors, clini-cal presentation, etiology, radiological findings, technical factors, and outcome parameters were presented using exploratory and descriptive statistics. Results: Abscesses were located in the psoas (n = 25, 55.3%), renal-perirenal (n = 7, 14.8%), and pararenal (n = 14, 29.7%) compartments. The mean preprocedural volume was 263.3 (30-1310) ml. Pain (abdominal and back) (57.4%) and fever (17%) were the most frequent presenting symptoms. The most common predisposing factors were previous surgery (n = 17, 36.1%) and diabetes mellitus (n = 11, 25.5%). Clinical success was attained in 89.3% of abscesses (definitive treatment 72.3% and partial success 17.0%). There was a statistically significant difference between the iatrogenic and non-iatrogenic groups regarding clinical success (p = 0.031). No mortality was encountered. The complication rate was 6.6% and were all minor. The average rate of recurrence was 10.6%. The mean time to catheter removal was 15.8 ± 13.2 days. Conclusions: PCD is a safe and effective procedure in the treatment of retroperitoneal abscesses. Procedure-related mortality, morbidity, and complication rates are low. Underlying etiology is a significant factor affecting the outcome. Nevertheless, PCD may provide definitive treatment in the majority of patients.

Percutaneous cholecystostomy: An update for the 2020s.

Cholecystectomy is the standard treatment of acute cholecystitis. Surgery, however, poses significant risks for patients with advanced age and/or comorbid conditions. For such patients, percutaneous cholecystostomy (PC) is the only option. This interventional procedure does not have any absolute contraindications because of the life-threatening nature of the disease, in which other treatment options cannot be offered due to their risks. Nonetheless, these risk factors necessitate performing PC under urgent, rapid, and in many cases suboptimal conditions. In this article, PC was revisited in the light of our extensive experience in addition to the most current literature. Pre-procedural evaluation including the risk assessment and procedural steps was presented in detail. If conducted properly, PC provides significant clinical improvement in the short term and is life-saving, especially in the elderly and in patients with comorbid diseases or high surgical risk. It may also be the definitive treatment method for acute cholecystitis.

Effect of trabeculated myocardial mass on left ventricle global and regional functions in noncompaction cardiomyopathy.

BACKGROUND: Left ventricular (LV) noncompaction cardiomyopathy is a rare cardiomyopathic subtype that has been recognized in recent years and is being diagnosed at an increased rate. There is no consensus regarding the diagnosis of the disease, and increased trabeculation rates that meet the existing diagnostic criteria may even be present in healthy asymptomatic people. This indicates that differentiating criteria for diagnosis are needed. AIM: To examine the increase in myocardial trabeculation and the change in left ventricular global and regional functions. METHODS: This retrospective study included 65 patients (28 females, 37 males) diagnosed with LV noncompaction cardiomyopathy who underwent cardiac magnetic resonance imaging between January 2011 and August 2016 and had a noncompacted/compacted myocardial thickness ratio of over 2.3 in more than one segment in the left ventricle. The distribution and ratios of trabeculations in apical, midventricular, and basal regions were examined in short-axis images obtained from cardiac magnetic resonance. In addition, by using short-axis cine images, regional ejection fraction (EF) and global EF were calculated using the Simpson method in the left ventricle at apical, basal, and midventricular levels. RESULTS: While the number of trabeculated segments were similar at the apical (3.2 ± 1.0) and midventricular levels, a statistically significant level of involvement was not observed at the basal level (0.4 ± 0.9) (P > 0.05). The highest noncompacted/compacted (trabeculation) ratio was observed at the apical level (3.9 ± 1.4), while this ratio was higher at the anterior (59%-89.4%) and lateral (62%-84.8%) segments (P > 0.05). Global EF was positively correlated with apical, midventricular, and basal regional EF (P < 0.05). However, there was no significant correlation between regional EF and the number of trabeculated segments or trabeculation ratio in all three regions; nor was there a significant correlation between regional EF and the number of trabeculated segments or trabeculation ratio in the entire LV (P > 0.05). CONCLUSION: No global or regional relationship was observed between LV dysfunction and trabeculation rate or the number of trabeculated segments. This limits the usefulness of change in LV functions in the differentiation between normal and pathological trabeculation.

The reliability of low-dose chest CT for the initial imaging of COVID-19: comparison of structured findings, categorical diagnoses and dose levels.

PURPOSE: The widespread use of computed tomography (CT) in COVID-19 may cause adverse biological effects. Many recommend to minimize radiation dose while maintaining diagnostic quality. This study was designed to evaluate the difference between findings of COVID-19 pneumonia on standard and low-dose protocols to provide data on the utility of the latter during initial imaging of COVID-19. METHODS: Patients suspected of having COVID-19 were scanned with a 128-slices scanner using two consecutive protocols in the same session (standard-dose scan: 120 kV and 300 mA; low-dose scan: 80 kV and 40 mA). Dose data acquisition and analysis was performed using an automated software. High and low-dose examinations were anonymized, shuffled and read by two radiologist with consensus according to a highly structured reporting format that was primarily based on the consensus statement of the RSNA. Accordingly, 8 typical, 2 indeterminate, and 7 atypical findings were investigated. Cases were then assigned to one of the categories: (i) Cov19Typ, typical COVID-19; (ii) Cov19Ind, indeterminate COVID-19; (iii) Cov19Aty, atypical COVID-19; (iv) Cov19Neg, not COVID-19. McNemar test was used to analyze the number of disagreements between standard and low-dose scans regarding paired proportions of structured findings. Inter- test reliability was tested using kappa coefficient. RESULTS: The study included 740 patients with a mean age of 44.05±16.59 years. The median (minimum-maximum) dose level for standard protocol was 189.98 mGy•cm (98.20-493.54 mGy•cm) and for low-dose protocol was 15.59 mGy•cm (11.59-32.37 mGy•cm) differing by -80 and -254 mGy•cm from pan-European diagnostic reference levels. Only two findings for typical, one finding for indeterminate, and three findings for atypical categories were statistically similar (p > 0.05). The difference in other categories resulted in significantly different final diagnosis for COVID-19 (p < 0.001). Overall, 626 patients received matching diagnoses with the two protocols. According to intertest reliability analysis, kappa value was found to be 0.669 (p < 0.001) to indicate substantial match. CT with standard-dose had a sensitivity of 94% and a specificity of 72%, while CT with low-dose had a sensitivity of 90% and a specificity of 81%. CONCLUSION: Low kV and mA scans, as used in this study according to scanner manufacturer's global recommendations, may significantly lower exposure levels. However, these scans are significantly inferior in the detection of several individual CT findings of COVID-19 pneumonia, particularly the ones with GGO. Therefore, they should not be used as the protocol of choice in the initial imaging of COVID-19 patients during which higher sensitivity is required.

Clinical approach to patients admitted to the emergency room due to acute cholecystitis during the COVID-19 pandemic and percutaneous cholecystostomy experience.

BACKGROUND: Acute cholecystitis (AC), a common complication of gallstones, is responsible for a significant part of emergency applications, and cholecystectomy is the only definitive treatment method for AC. Early cholecystectomy has many reported advantages. Operation-related morbidity and mortality have increased during the COVID-19 pandemic. In this study, our aim is to present our general clinical approach to patients who were diagnosed with AC during the pandemic and our percutaneous cholecystostomy experience during this period. METHODS: This study included 72 patients who were presented to our hospital's emergency room between March 11 and May 31, 2020, with AC. Patients were divided into three groups based on their treatment: outpatients (Group 1), inpatients (Group 2) and patients undergoing percutaneous cholecystostomy (Group 3). These three groups were compared by their demographic and clinical characteristics. RESULTS: There were 36 (50%) patients in Group 1, 25 (34.7%) patients in Group 2, and 11 (15.3%) patients in Group 3. The demographic characteristics of the patients were similar. The CRP and WBC levels of the patients in Group 3 were significantly higher compared to the other groups. Moreover, the wall of the gallbladder was thicker and the size of the gallbladder was larger in Group 3. Patients had percutaneous cholecystostomy at the median of 3.5 days and the length of hospital stay was longer compared to Group 2 (3.9 days versus 9.2 days, p=0.00). The rate of re-hospitalization after discharge was similar in Group 2 and Group 3, but none of the patients in Group 1 required hospitalization. None of 72 patients developed an emergency condition requiring surgery, and there was no death. CONCLUSION: Although many publications emphasize that laparoscopic cholecystectomy (LC) can be performed with low morbidity at the first admission in acute cholecystitis, it is a clinical condition that can be delayed in the COVID-19 pandemic and other similar emergencies. Thus, percutaneous cholecystostomy should be effectively employed, and its indications should be extended if necessary (e.g., younger patients, patients with lower CCI or ASA). This approach may enable us to protect both patients and healthcare professionals that perform the operation from the risk of COVID-19.

The antimicrobial efficacy of shielded ultraviolet germicidal irradiation in CT rooms with intense human circulation.

PURPOSE: Computed tomography (CT) premises are one of the strategic points in the spread of hospital-acquired infections. Ultraviolet germicidal irradiation (UVGI) is an effective method that could potentially be used to purify the ambient air in them. However, it cannot be directly used in the presence of humans and, therefore, it is not operationally suitable in such units with continuous human circulation. Newer devices have been developed to purify air with more efficient and shielded UV-C sources. This study aims to assess the microbial air contamination in CT scanning rooms and investigates the efficacy and technical considerations of shielded UV-C arrays. METHODS: Two shielded UVGI systems, each equipped with 15 Watt UV-C LED arrays, were tested in a very busy CT unit. Initially, a pilot study was performed to determine ambient microorganisms under routine conditions before UVGI installation, followed by three basic scenarios of UVGI use under normal and abnormal conditions: A, UVGI, with both air-conditioning (AC) and ventilation on; B, UVGI, with AC on and ventilation off; C, UVGI, with both AC and ventilation off. Ambient air was sampled in various time points before and after the initialization of UV irradiation and analyzed for colony formation. RESULTS: The mean total colony count in the pilot study was 1360±450 CFU/m3. Pre-UVGI colony count was 3510 CFU/m3 for Scenario A, ~10000 CFU/m3 for Scenario B and 990 CFU/m3 for Scenario C. Thirty minutes after UVGI, total colony counts in all three scenarios dropped to 30 to 70 CFU/m3. Under normal operating conditions and UVGI, the mean colony count was found as 21.4±13.5 CFU/m3 and the average efficacy of the UVGI was found as 99.39%. CONCLUSION: This study identified substantial microbial air contamination in CT scanning rooms during normal and abnormal operating conditions. UV-C LED arrays effectively eliminate these microbiological contaminants. This effect is also observed under abnormal operating conditions where no other means of ventilation or air conditioning exists.