Multiparametric MRI in rectal cancer

MRI has a pivotal role in both pretreatment staging and posttreatment evaluation of rectal cancer. The accuracy of MRI in pretreatment staging is higher compared with posttreatment evaluation. This occurs due to similar signal intensities of tumoral and posttreatment fibrotic, necrotic, and inflamed tissue. This limitation occurs with conventional MRI of the rectum with morphologic sequences. There is a need towards increasing the accuracy of MRI, especially for posttreatment evaluation. The term multiparametric MRI implies addition of functional sequences, namely, diffusion and perfusion to the routine protocol. This review summarizes the technique, potential implications and previously published studies about multiparametric MRI of rectal cancer

Multiparametric MRI of rectal cancer—repeatability of quantitative data: a feasibility study

PURPOSEIn this study, we aimed to analyze the repeatability of quantitative multiparametric rectal magnetic resonance imaging (MRI) parameters with different measurement techniques.METHODSAll examinations were performed with 3 T MRI system. In addition to routine sequences for rectal cancer imaging protocol, small field-of-view diffusion-weighted imaging and perfusion sequences were acquired in each patient. Apparent diffusion coefficient (ADC) was used for diffusion analysis and ktrans was used for perfusion analysis. Three different methods were used in measurement of these parameters; measurements were performed twice by one radiologist for intraobserver and separately by three radiologists for interobserver variability analysis. ADC was measured by the lowest value, the value at maximum wall thickness, and freehand techniques. Ktrans was measured at the slice with maximum wall thickness, by freehand drawn region of interest (ROI), and at the dark red spot with maximum value.RESULTSA total of 30 patients with biopsy-proven rectal adenocarcinoma were included in the study. The mean values of the parameters measured by the first radiologist on the first and second measurements were as follows: mean lowest ADC, 721.31±147.18 mm2/s and 718.96±135.71 mm2/s; mean ADC value on the slice with maximum wall thickness, 829.90±144.24 mm2/s and 829.48±149.23 mm2/s; mean ADC value measured by freehand ROI on the slice with maximum wall thickness, 846.56±136.31 mm2/s and 848.23±144.15 mm2/s; mean ktrans value on the slice with maximum wall thickness, 0.219±0.080 and 0.214±0.074; mean ktrans by freehand ROI technique (including as much tumoral tissue as possible), 0.208±0.074 and 0.207±0.069; mean ktrans measured from the dark red foci, 0.308±0.109 and 0.311±0.105. Intraobserver agreement was very good among diffusion and perfusion parameters obtained with all three measurement techniques. Interobserver agreement was very good, except for one of the measurement techniques. As far as interobserver variability is considered, only ADC value measured on the slice with maximum wall thickness differed significantly.ConclusionMultiparametric MRI of rectum, using ADC as the diffusion and ktrans as the perfusion parameter is a repeatable technique. This technique may potentially be used in prediction and evaluation of neoadjuvant treatment response. New studies with larger patient groups are needed to validate the role of multiparametric MRI

Radiological approach to COVID-19 pneumonia with an emphasis on chest CT

Coronavirus disease 2019 (COVID-19) has recently become a worldwide outbreak with several millions of people infected and more than 160.000 deaths. A fast and accurate diagnosis in this outbreak is critical to isolate and treat patients. Radiology plays an important role in the diagnosis and management of the patients. Among various imaging modalities, chest CT has received attention with its higher sensitivity and specificity rates. Shortcomings of the real-time reverse transcriptase-polymerase chain reaction test, including inappropriate sample collection and analysis methods, initial false negative results, and limited availability has led to widespread use of chest CT in the diagnostic algorithm. This review summarizes the role of radiology in COVID-19 pneumonia, diagnostic accuracy of imaging, and chest CT findings of the disease

Knowing the ABCs: Teaching the principles of radiology to medical students in Turkey

Background: Radiology education in Turkey is mainly taught during clinical years of medical school and often lacks main principles. Exposure to the fundamentals of radiology at an early stage of medical education may drastically help students generate a better understanding of radiology and expand their interest in the specialty. With the Principles of Radiology Course that we provided, pre- and post-session tests, and assessment survey at the end of the course, we aimed to evaluate the effectiveness of such an online course among Turkish medical students. Methods: A total of nine online sessions on imaging modalities principles was developed by radiology professors. Each session was given through Zoom by radiologists from different U.S.-institutions to Turkish medical students from state (n = 33) and private (n = 8) universities. Pretests and post-tests were given to participants via Qualtrics before and after each session, respectively. Paired two-sample t-tests were conducted to detect the variance and p=-.05 was used as the significance level. An evaluation survey was distributed at the end of the course to collect their feedback through SurveyMonkey. Results: A total of 1,438 predominantly Turkish (99.32%) medical students engaged with this course. An average of 506 students completed both pre-test and post-test. There was a statistically significant (p <.001) increase in the scores in post-test (mean[range]:7.58[5.21–8.53]) relative to pre-test (mean[range]:5.10[3.52–8.53]). Four hundred and thirty-nine participants (F/M:63.33%/35.54%) completed the end-of-course survey. A total of 71% and 69.70% of the participants strongly agreed that the course would be useful in their clinical practice and had increased their understanding of radiology. They also reported that their level of confidence in the subjects had increased 68% and reached a weighted average of 3.09/4. The survey revealed that 396 (90.21%) of the participants strongly or somewhat agree that introductory principles and concepts should be presented in earlier years of medical education. Compared to in-person education, 358 (81.55%) found the course extremely or very convenient. Conclusion: Online lecture series consisting of the principles of the radiological imaging modalities can be offered to Turkish medical students to enhance their grasp of the various imaging modalities and their correct clinical application

Adrenal Kortikal Karsinom’da Bilgisayarlı Tomografi Görüntüleme Bulguları

Amaç: Adrenal kortikal karsinomun (AKK) Bilgisayarlı Tomografi (BT) görüntüleme özelliklerini araştırmak. Gereç ve yöntem: Patolojik olarak AKK tanısı almış 15 hastanın (K/E: 8/7, ortanca [aralık]: 53 yıl [31-74 yıl]) kalitatif ve kantitatif BT bulguları retrospektif olarak değerlendirildi. Lezyonların fonksiyonel durumlarına klinik notlardan ulaşıldı. Bulgular: Hastaların patolojik tanısı cerrahi (n=12) veya cerrahi eşliğinde biyopsi (n=3) ile konulmuştu. 9 lezyon (%60) fonksiyonel, 6 lezyon (%40) non-fonksiyoneldi. Fonksiyonel lezyonların 5’i androjen, 4’ü kortizon üretmekteydi. Kalitatif değerlendirmede 13 lezyon (%93) nekroz, 3 lezyon (%20) kalsifikasyon ve 1 lezyon (%7) makroskobik yağ içeriyordu. Lezyonların tamamı iyi sınırlı olup heterojen kontrastlanmaktaydı. Lezyonların ortanca (aralık) boyutu 9,7 cm (6.3-18 cm) idi. Prekontrast, arteriyel faz, portal faz ve geç faz ortanca (aralık) dansite değerleri sırasıyla şöyleydi: 34 HU (22-41 HU), 46 HU (27-65 HU), 60 HU (29-90 HU), 48 HU (28-64 HU). 9 hastada 15. dakika geç faz elde olunmuştu. Ortanca (aralık) mutlak (MKYY) ve bağıl (BKYY) kontrast yıkanma yüzdeleri sırasıyla şöyleydi: %48,8 (%-3.8-62.5) ve %21 (%-1.5-30.8). Sadece bir lezyonun MKYY değeri %60’in üzerindeydi. Sonuç: AKK’lar BT’de genellikle büyük (&gt;6cm), iyi sınırlı, heterojen kontrastlanan, nekrotik kitleler şeklinde görülür. Makroskobik yağ ve kalsifikasyon içerebilir ve geç faz imajlarda sınırlı kontrast yıkanması gösterirler

Investigation of the correlation between CT densitometry and histopathologic results in the evaluation of fatty infiltration of the liver in the preoperative radiologic assessment of the living liver donor candidates

İstanbul Bilim Üniversitesi, Tıp Fakültesi, Radyoloji Anabilim DalıBu çalışmanın amacı karaciğer yağlanma derecesinin değerlendirilmesinde BT dansitometri tekniğinin tanısal doğruluğunu CVKN donör adayları üzerinde araştırmaktı. Yaşları 19-56 arasında değişen 93 olgu değerlendirildi(Ort: 32,7 yıl, SS: 8,7 yıl). Donör adaylarının preoperatif radyolojik değerlendirmesinde rutin olarak gerçekleştirilen BT çalışmasında, prekontrast imajlarda, karaciğer ve dalağın ana vasküler yapılardan yoksun alanlarına örneklemler yerleştirildi. Bulunan değerlerin ortalamaları alınarak HU cinsinden ortalama karaciğer(MSA) ve ortalama dalak(MSA) dansiteleri bulundu. Bu değerler kullanılarak karaciğer atenüasyon indeksi(LAI) hesaplandı(LAI=MHA-MSA) Cerrahi sırasında wedge biyopsi ya da preoperatif dönemde iğne biyopsisi yapılmış olguların histopatolojik sonuçları, LAI değerleri ile karşılaştırılarak analiz edildi. Histopatolojik sonuçlara göre olguların 58 (62,4%)’ inde hiç yağlanma görülmezken 35(37,6%)’ inde yağlanma görülmüştür. Karaciğer yağlanması görülen 1’er(2,9%) olguda; 15%, (15-20)%, 20%, 30% ve 35%, 2’şer (5,7%) olguda 1%, (10-15)%, (20-25)% , (25-30)% ve 40%, 3(8,6%) olguda 2%, 4(11,4%) olguda (5-10)%, 6(17,1%)olguda 5% ve 7(20%) olguda 10% yağlanma saptanmıştır. Histopatolojik değerlendirmede yağlanma derecesi ≤ %5 saptanan 69 olgunun CVKN öncesi yapılan BT dansitometre analizlerine göre 63’ünde yağlanma derecesinin, ≤ %5, 6’ sında ise yağlanma derecesinin %5-30 arasında olduğu görülmüştür. Halihazırda kullanılan LAI değerlerine göre kabul edilen yağlanma dereceleri Tablo 9’da verilmiştir. Çalışmamızda bu değerlerin histopatolojik sonuçlar ile uyuşumu-korelasyon değeri r=0,661 olup orta düzey ilişki ile uyumlu olarak değerlendirilmiştir. Daha yüksek bir uyuşumu-korelasyon elde etmek amacı ile histopatolojik yağlanmayı BT ile benzer gruplara ayırdığımızda (≤ %5 , %6-%30 ve %30≤ ) ayırt edici LAI kestirim değerleri şöyle bulundu: 5≤% yağlanma için LAI ≥6, [6-30]% yağlanma için 3≤ LAI ≤5 ve %30 ve üzeri yağlanma için ise LAI ≤3. Bu şekilde elde ettiğimiz uyuşumu-korelasyon değeri (r=0,724 ) (p<0,001) olup, mükemmele yakın ilişki ile uyumlu olarak değerlendirilmiştir. Bu şekilde elde edilen LAI kestirim değerlerinin halihazırda kullanılan derecelendirmeye göre histopatoloji ile daha yüksek uyuşma-korelasyon içerisinde olduğu sonucuna varılmıştır. LAI değerlerinden faydalanılarak, BT dansitometre tekniği ile karaciğer yağlanmasının tahmini altın standart yöntem olan histopatolojik tetkike göre daha kolay, hızlı ve non-invazivdir. BT dansitometri yağlanma varlığını yüksek özgüllük (%75) ve duyarlılıkla (%75) tahmin edebilmekte böylece CVKN donör adaylarında invaziv bir yöntem olan perkütan biyopsiden kaçınılabilmektedir.The purpose of this study was to determine the diasgnostic value of CT densitometry in the quantification of fat content in human liver in living liver transplantation donor candidates. The study was performed on 93 living liver donor candidates who were between 19-56 of ages(32.7 years ± 8.7). In the native CT images which is obtained in the routine preoperative radiologic evaluation of donor candidates, equally sized region of interest were placed on nonvascular areas of liver and spleen. Mean hepatic attenuation (MHA) and mean splenic attenuation (MSA) were determined using ROI measurements and calculated LAI values. Needle and wedge biopsy materials were assesed histopathologically to determine the actual degree of hepatosteatosis and were compared to LAI values. At histopathological analysis, there were no steatosis in 58(%62.4) of 93 donor candidates. The rest of the donors had steatosis in vary of rate. There were 69 donors who have %5 or less steatosis in histopathological evaluation. CT densitometry predicted ≤ 5% hepatosteatosis in 63 subjects. There were %5-30 steatosis in other 6 donors with CT densitometry. There was a well correlation (r=0,661) between the LAI values and histopathological results. To get a better correlation we divided the histopathological stetosis into three group(≤ %5 , %6-%30 ve %30≤ ) as well like CT densitometry. The new cut off value for LAI was ≥6 for %5 or less steatosis, 3≤ LAI ≤5 for [6-30] steatosis and ≤3 for %30 or more steatosis. There was a great correlation (r=0,724) between these LAI values and histopathologic results. The CT densitometry is a noninvasive and easy technique in the assesment of the macrovesicular hepatosteatosis. It is faster and easier than histopathological evaluation. LAI values correctly predict the presence of fatty infiltration with significant sensitivity (75%)and specficity (74%) and in this way BT densitometry technique prevents invasive percutenous liver biopsy