Evaluation of Neoadjuvant Chemoradiotherapy Response in Rectal Cancer Using MR Images and Deep Learning Neural Networks.

INTRODUCTION: The aim of the study was to develop deep-learning neural networks to guide treatment decisions and for the accurate evaluation of tumor response to neoadjuvant chemoradiotherapy (nCRT) in rectal cancer using magnetic resonance (MR) images. METHODS: Fifty-nine tumors with stage 2 or 3 rectal cancer that received nCRT were retrospectively evaluated. Pathological tumor regression grading was carried out using the Dworak (Dw-TRG) guidelines and served as the ground truth for response predictions. Imaging-based tumor regression grading was performed according to the MERCURY group guidelines from pre-treatment and post-treatment para-axial T2-weighted MR images (MR-TRG). Tumor signal intensity signatures were extracted by segmenting the tumors volumetrically on the images. Normalized histograms of the signatures were used as input to a deep neural network (DNN) housing long short-term memory (LSTM) units. The output of the network was the tumor regression grading prediction, DNN-TRG. RESULTS: In predicting complete or good response, DNN-TRG demonstrated modest agreement with Dw-TRG (Cohen's kappa= 0.79) and achieved 84.6% sensitivity, 93.9% specificity, and 89.8% accuracy. MR-TRG revealed 46.2% sensitivity, 100% specificity, and 76.3% accuracy. In predicting a complete response, DNN-TRG showed slight agreement with Dw-TRG (Cohen's kappa= 0.75) with 71.4% sensitivity, 97.8% specificity, and 91.5% accuracy. MR-TRG provided 42.9% sensitivity, 100% specificity, and 86.4% accuracy. DNN-TRG benefited from higher sensitivity but lower specificity, leading to higher accuracy than MR-TRG in predicting tumor response. CONCLUSION: The use of deep LSTM neural networks is a promising approach for evaluating the tumor response to nCRT in rectal cancer.

Evaluating complete response prediction rates in locally advanced rectal cancer with different radiomics segmentation approaches.

Purpose: Studies examining prediction of complete response (CR) in locally advanced rectum cancer (LARC) from pre/post chemoradiotherapy (CRT) magnetic resonance imaging (MRI) are performed mostly with segmentations of the tumor, whereas only in two studies segmentation included tumor and mesorectum. Additionally, pelvic extramesorectal region, which is included in the clinical target volume (CTV) of radiotherapy, may contain information. Therefore, we aimed to compare predictive rates of radiomics analysis with features extracted from segmentations of tumor, tumor+mesorectum, and CTV. Methods and materials: Ninety-three LARC patients who underwent CRT in our institution between 2012 and 2019 were retrospectively scanned. Patients were divided into CR and non-CR groups. Tumor, tumor+mesorectum and CTV were segmented on T2 preCRT MRI images. Extracted features were compared for best area under the curve (AUC) of CR prediction with 15 machine-learning models. Results: CR was observed in 25 patients (26.8%), of whom 13 had pathological, and 12 had clinical complete response. For tumor, tumor+mesorectum and CTV segmentations, the best AUC were 0.84, 0.81, 0.77 in the training set and 0.85, 0.83 and 0.72 in the test set, respectively; sensitivity and specificity for the test set were 76%, 90%, 76% and 71%, 67% and 62%, respectively. Conclusion: Although the highest AUC result is obtained from the tumor segmentation, the highest accuracy and sensitivity are detected with tumor+mesorectum segmentation and these findings align with previous studies, suggesting that the mesorectum contains valuable insights for CR. The lowest result is obtained with CTV segmentation. More studies with mesorectum and pelvic nodal regions included in segmentation are needed.

Complete Response Evaluation of Locally Advanced Rectal Cancer to Neoadjuvant Chemoradiotherapy Using Textural Features Obtained from T2 Weighted Imaging and ADC Maps.

BACKGROUND: The prediction of pathological responses for locally advanced rectal cancer using magnetic resonance imaging (MRI) after neoadjuvant chemoradiotherapy (CRT) is a challenging task for radiologists, as residual tumor cells can be mistaken for fibrosis. Texture analysis of MR images has been proposed to understand the underlying pathology. OBJECTIVE: This study aimed to assess the responses of lesions to CRT in patients with locally advanced rectal cancer using the first-order textural features of MRI T2-weighted imaging (T2-WI) and apparent diffusion coefficient (ADC) maps. METHODS: Forty-four patients with locally advanced rectal cancer (median age: 57 years) who underwent MRI before and after CRT were enrolled in this retrospective study. The first-order textural parameters of tumors on T2-WI and ADC maps were extracted. The textural features of lesions in pathologic complete responders were compared to partial responders using Student's t- or Mann-Whitney U tests. A comparison of textural features before and after CRT for each group was performed using the Wilcoxon rank sum test. Receiver operating characteristic curves were calculated to detect the diagnostic performance of the ADC. RESULTS: Of the 44 patients evaluated, 22 (50%) were placed in a partial response group and 50% were placed in a complete response group. The ADC changes of the complete responders were statistically more significant than those of the partial responders (P = 0.002). Pathologic total response was predicted with an ADC cut-off of 1310 x 10-6 mm2/s, with a sensitivity of 72%, a specificity of 77%, and an accuracy of 78.1% after neoadjuvant CRT. The skewness of the T2-WI before and after neoadjuvant CRT showed a significant difference in the complete response group compared to the partial response group (P = 0.001 for complete responders vs. P = 0.482 for partial responders). Also, relative T2-WI signal intensity in the complete response group was statistically lower than that of the partial response group after neoadjuvant CRT (P = 0.006). CONCLUSION: As a result of the conversion of tumor cells to fibrosis, the skewness of the T2-WI before and after neoadjuvant CRT was statistically different in the complete response group compared to the partial response group, and the complete response group showed statistically lower relative T2-WI signal intensity than the partial response group after neoadjuvant CRT. Additionally, the ADC cut-off value of 1310 × 10-6 mm2/s could be used as a marker for a complete response along with absolute ADC value changes within this dataset.

Case Report: Role of Interventional Radiology in the Management of Patients with Alveolar Echinococcus: Successful Management of Three Cases.

Alveolar echinococcus (AE) is an infestation by Echinococcus multilocularis. Partial hepatectomy or liver transplantation is the first choice of treatment. However, the disease is usually diagnosed at an unresectable stage. In those cases, invasion of the bile ducts and vessels, and necrosis in the center of the lesion lead to severe complications, such as cholangitis and liver abscesses. Palliative surgery has been reported to not offer advantages in management, and percutaneous and endoscopic interventions have become more prominent in management. In this case series, outcomes in three cases with unresectable AE were reported. In one of the cases, interventional procedures were used to manage the complications after surgery. In the second case, the cystic component was aspirated to decrease the size before the surgery and in the third case, it was used to drain biliary tree and no surgery was done.

Stromal fibrosis: imaging features with diagnostic contribution of diffusion-weighted MRI.

OBJECTIVE: To describe magnetic resonance imaging (MRI) and ultrasonography findings of breast stromal fibrosis (SF) and compare apparent diffusion coefficient (ADC) stromal fibrosis values with breast cancer and normal parenchyma. METHODS: 45 patients (ages 22‒74) with histopathologically proven SF who underwent MRI were included in this study. Their MRI and ultrasonography features were examined and categorized. The mean ADC values for SF, contralateral normal parenchyma, and breast malignancy of the control group values were calculated and compared among each other. RESULTS: The vast majority of SF on sonography showed features suggestive of malignancy: (1) irregular in shape 25/45 (55%); (2) indistinct in margin 27/45 (60%); and (3) hypoechoic 39/45 (87%) with posterior acoustic shadowing 11/45 (24%). An SF MRI showed a mass in 12/45 (26%) and non-mass enhancement in 33/45 (74%), mostly with irregular (8/12; 67%) shape. Non-mass lesions showed heterogeneous (12/33), clumped (9/33), and homogenous (9/33) enhancement. The initial SF contrast uptake rate varied between slow (57%), rapid (22%), and medium (21%). Delayed SF enhancement may be persistent (66%) or plateau (34%). Small cysts were located around/near 21 (47%) of lesions. Ductal ectasia was found in 14 (31%) of all patients. Mean ADCs of parenchyma, SF, and malignancy were 1.32 ± 0.32, 1.23 ± 0.25, and 0.99 ± 0.24 × 10-3 mm2 sec-1, respectively. CONCLUSION: SF often mimics breast carcinoma on imaging and leads the radiology‒pathology disagreement. In terms of distinguishing SF from malignancy, ADC could be a significant and promising value in diffusion-weighted MRI along with conventional sequences. Slow initial uptake with delayed persistent contrast enhancement in a non-mass lesion with relatively higher ADC values are very helpful for differentiating SF from malignancy. The presence of small cysts and ductal ectasia were common findings around/near the SF. Advances in knowledge: A quantitative analysis for measuring ADC values along with additional MRI features can be very helpful in distinguishing SF from malignant lesions.

Percutaneous Treatment of Non-parasitic Splenic Cysts: Long-Term Results for Single- Versus Multiple-Session Treatment.

PURPOSE: The aim of this study was to investigate the efficacy and safety of percutaneous sclerotherapy for non-parasitic splenic cysts (NPSCs). The secondary aims were to introduce puncture-aspiration-injection-reaspiration (PAIR) technique in the treatment of NPSCs and to compare multiple- and single-session techniques. MATERIALS AND METHODS: This retrospective study included 24 (17 females, 7 males) patients, treated between the years 1997 and 2015. Three techniques were used. Group A (n = 8), Group B (n = 6) and Group C (n = 10) were treated by PAIR, single-session catheterization and multiple-session catheterization, respectively. Since both PAIR and single-session catheterization techniques are carried out in a single session, Group A and Group B were evaluated in one group (Group A + B). Group A + B was compared with Group C in terms of patient demographics, the initial volume of the cysts, follow-up periods, complication and hospitalization rates and follow-up results. Recurrence and reduction rates were evaluated for two groups. RESULTS: Technical success rate was 100%. The mean follow-up period was 68.9 months. Recurrence detected in 7 (29.1%) patients. Final reduction rate was between 40.7 and 100% (median 96.4%) with a significant difference in cyst volume (p < 0.05). There was no significant difference regarding recurrence rates (p = 1) and the final reduction rates (p = 0.51) between the two groups. CONCLUSION: Percutaneous sclerotherapy is a minimally invasive technique, preserving maximum tissue while effectively treating NPSCs. Single-session sclerotherapy which reduces hospitalization days and increases patient comfort is as effective as multi-session sclerotherapy as the initial procedure. This study supports that single-session sclerotherapy should be a valid treatment option.

Role of diffusion-weighted MRI in the differential diagnosis of endometrioid and non-endometrioid cancer of the uterus.

Background Many publications have examined the relationship between apparent diffusion coefficient (ADC) values and tumor grade in endometrial cancer. Nevertheless, none were designed to evaluate according to the histopathological type of endometrioid and non-endometrioid tumors. Purpose To evaluate the role of diffusion-weighted imaging (DWI) in the differential diagnosis of endometrioid and non-endometrioid cancer of the uterus, by comparing them with contrast-enhanced magnetic resonance imaging (MRI) findings. Material and Methods Institutional review board approval and informed consent were obtained. The MRI findings of 63 patients with endometrial cancer were retrospectively evaluated and divided into four groups: Grades I, II, and III endometrioid tumors, and non-endometrioid tumors. ADC values, DWI quotients ( b = 1000 s/mm2), and post-contrast signal intensities between lesions and the myometrium (b1000q-Cq values) were evaluated. The one-way-ANOVA, student's t-test, Kruskal-Wallis test, and receiver operating characteristic (ROC) analysis were used for statistical evaluation. Results Mean ADC values were 0.86 ± 0.14 in Grade I, 0.80 ± 0.7 in Grade II, 0.71 ± 0.14 in Grade III for endometrioid tumors, and 0.70 ± 0.12 in non-endometrioid tumors. There was a significant difference in ADC values between Grade I and Grade III ( P = 0.006), and non-endometrioid tumors ( P = 0.003). The difference was also significant between Grades I + II and Grade III ( P = 0.009), and non-endometrioid tumors ( P = 0.004). Besides, there was a significant difference between endometrioid and non-endometrioid tumors ( P = 0.022). However, when considering b1000q (F = 0.640, P = 0.593) and Cq (χ2 = 6.233; P = 0.101), no significant difference was detected among the groups. Conclusion The difference in ADC values between the endometrioid and non-endometrioid tumors was statistically significant. However, the difference in DWI and contrast-enhancement findings were not statistically significant. Furthermore, the mean ADC values had an inverse relationship with tumor grade in the endometrioid cancer group.

Role of diffusion weighted MRI in the differential diagnosis of endometrial cancer, polyp, hyperplasia, and physiological thickening.

Our purpose was to evaluate the role of diffusion-weighted imaging (DWI) in the diagnosis of various common pathologies of the uterine cavity, by comparing them with contrast-enhanced MRI findings. One hundred sixty-four patients with lesions in endometrial cavity were included in the study. The patients were grouped in four (one malignant and three benign groups). We have observed that the differences of the apparent diffusion coefficient, b1000q, and Cq values between various common benign and malignant lesions were statistically significant (P<.001). However, the differences of the values between benign groups were not statistically significant (P>.05). Alternatively, endometrial polyp group's signal intensity on DWI was different than the other groups.

Multimodality Imaging Findings of a Renal Aspergilloma.

BACKGROUND: Renal aspergillosis is a rare infection that usually occurs in persons with a predisposition for this condition. Its differential diagnosis includes primary and metastatic renal malignancies, pyelonephritis and secondary abscess formation, granulomatous disorders, and renal infarction. We aim to stress the role of multimodality imaging and percutaneous biopsy in the diagnosis of this condition. CASE REPORT: We present diffusion weighted imaging (DWI) and positron emission tomography-computed tomography (PET-CT) findings in addition to conventional imaging modalities in a 55-year-old man with secondary renal aspergilloma. CONCLUSION: Radiological imaging methods are an integral part of diagnostic workup for renal aspergillosis. A definitive diagnosis is made by histopathological and/or microbiological examination of the material obtained via percutaneous biopsy under guidance of imaging methods.

Multimodality imaging in diagnosis and management of alveolar echinococcosis: an update.

Alveolar echinococcosis is a parasitic disease limited to the northern hemisphere. The disease occurs primarily in the liver and shows a profile mimicking slow-growing malignant tumors. Echinococcus multilocularis infection is fatal if left untreated. It can cause several complications by infiltrating the vascular structures, biliary tracts, and the hilum of the liver. As it can invade the adjacent organs or can spread to distant organs, alveolar echinococcosis can easily be confused with malignancies. We provide a brief review of epidemiologic and pathophysiologic profile of alveolar echinococcosis and clinical features of the disease. This article focuses primarily on the imaging features of alveolar echinococcosis on ultrasonogra-phy, computed tomography, magnetic resonance imaging, diffusion-weighted imaging and positron emission tomography-computed tomography. We also reviewed the role of radiology in diagnosis, management, and follow-up of the disease.

Imaging Appearances of Paratesticular Fibrous Pseudotumor.

BACKGROUND: In this paper the clinical and radiological features of three cases with paratesticular fibrous pseudotumor were presented after a retrospective analysis of medical archives of our hospital. CASE REPORT: Each of the three cases had unilateral, multiple nodular lesions with smooth borders accompanied by a hydrocele. On sonographic examination, the lesions showed echogenicity similar to, or slightly lower than, the testis, and the two large lesions had posterior acoustic shadowing. Color Doppler ultrasound examination of two cases showed intralesional vascularity of mild-to-moderate degree. All lesions appeared hypointense compared to testicular tissue on T1W and T2W magnetic resonance images. Moderate-to-high enhancement was observed in the diffuse pattern after intravenous injection of contrast material. An intraoperative pathological examination was performed and local excision carried out in all three cases. CONCLUSIONS: Fibrous pseudotumor is a rare benign paratesticular lesion, which can be confused with malignant masses. Imaging procedures play an important role in correct diagnosis. Unfamiliarity with imaging findings of paratesticular fibrous pseudotumor may eventuate in an unnecessary orchiectomy.

Feasibility of 3-dimensional sampling perfection with application optimized contrast sequence in the evaluation of patients with hydrocephalus.

PURPOSE: This study aimed to investigate the effectiveness and additive value of T2W 3-dimensional sampling perfection with application optimized contrast (3D-SPACE) with variant flip-angle mode in imaging of all types of hydrocephalus. Our secondary objective was to assess the reliability of 3D-SPACE sequence and correspondence of the results with phase-contrast magnetic resonance imaging (PC-MRI)-based data. MATERIALS AND METHODS: Forty-one patients with hydrocephalus have undergone 3-T MRI. T2W 3D-SPACE sequence has been obtained in addition to routine hydrocephalus protocol. Cerebrospinal fluid circulation, presence/type/etiology of hydrocephalus, obstruction level scores, and diagnostic levels of confidence were evaluated separately by 2 radiologists. In the first session, routine sequences with PC-MRI were evaluated, and in another session, only 3D-SPACE and 3-dimensional magnetization prepared rapid acquisition gradient echo sequences were evaluated. Results obtained in these sessions were compared with each other and those obtained in consensus session. RESULTS: Agreement values were very good for both 3D-SPACE and PC-MRI sequences (P < 0.001 for all). Also, the correlation of more experienced reader's 3D-SPACE-based scores and consensus-based scores was perfect (κ = 1, P < 0.001).The mean value of PC-MRI-based confidence scores were lower than those obtained in 3D-SPACE and consensus sessions. CONCLUSIONS: T2W 3D-SPACE sequence provides morphologic cerebrospinal fluid flow data. It is a noninvasive technique providing extensive multiplanar reformatted images with a lower specific absorption rate. These advantages over PC-MRI make 3D-SPACE sequence a promising tool in management of patients with hydrocephalus.

Strain ratio measurement of femoral cartilage by real-time elastosonography: preliminary results.

OBJECTIVE: The purpose of this study was to evaluate strain ratio measurement of femoral cartilage using real-time elastosonography. METHODS: Twenty-five patients with femoral cartilage pathology on MRI (study group) were prospectively compared with 25 subjects with normal findings on MRI (control group) using real-time elastosonography. Strain ratio measurements of pathologic and normal cartilage were performed and compared, both within the study group and between the two groups. RESULTS: Elastosonography colour-scale coding showed a colour change from blue to red in pathologic cartilage and only blue colour-coding in normal cartilage. In the study group, the median strain ratio was higher in pathologic cartilage areas compared to normal areas (median, 1.49 [interquartile range, 0.80-2.53] vs. median, 0.01 [interquartile range, 0.01-0.01], p < 0.001, respectively). The median strain ratio of the control group was 0.01 (interquartile range, 0.01-0.01), and there was no significant difference compared to normal areas of the study group. There was, however, a significant difference between the control group cartilage and pathologic cartilage of the study group (p < 0.001). CONCLUSIONS: Elastosonography may be an effective, easily accessible, and relatively simple tool to demonstrate pathologic cartilage and to differentiate it from normal cartilage in the absence of advanced imaging facility such as MRI. KEY POINTS: • Elastosonography uses colour-maps and strain ratios for evaluating tissue deformability. • Colour change from blue to red and increased strain ratio represent softening. • Normal cartilage shows decreased compressibility, represented by blue colour and low strain ratio. • Pathologic cartilage shows increased compressibility, represented by red colour and high strain ratio. • Elastosonography may be used for differentiating pathologic cartilage from normal cartilage.

Disseminated alveolar hydatid disease resembling a metastatic malignancy: a diagnostic challenge-a report of two cases.

Alveolar hydatid disease or alveolar echinococcosis is a disease of the parasite Echinococcus multilocularis that is potentially fatal if left untreated. It primarily involves the liver but can be disseminated to other organs like the lungs and the brain by hematogenous route. Multiorgan involvement and the aggressive appearance of lesions make alveolar hydatid disease easy to confuse with a metastatic malignancy. For this reason, histopathological confirmation is essential for definite diagnosis. We present the imaging features of this disease in two patients in order to emphasize that these lesions can be easily misdiagnosed as malignancies.

Is coracoacromial arch angle a predisposing factor for rotator cuff tears?

PURPOSE: The aim of the present study was to investigate whether coracoacromial arch angle is a predisposing factor for rotator cuff tears. METHODS: Shoulder magnetic resonance imaging (MRI) examinations of 40 patients having shoulder arthroscopy due to rotator cuff tears and 28 patients with normal MRI findings were evaluated retrospectively. Acromio-humeral distance, coraco-humeral distance, the angle between the longitudinal axis of the coracoacromial ligament and longitudinal axis of the acromion (coracoacromial arch angle), and thickness of the coracoacromial ligament were measured. RESULTS: In patients with rotator cuff pathology the mean coraco-humeral distance was 7.88±2.37 mm, the mean acromio-humeral distance was 7.89±2.09 mm, and the mean coracoacromial arch angle was 132.38°±6.52° compared to 11.67±1.86 mm, 11.15±1.84 mm, and 116.95°±7.66° in the control group, respectively (P < 0.001, for all). In regression analysis, all three parameters were found to be significant predictors of rotator cuff tears. The mean thickness of the coracoacromial ligament was not significantly different between the patient and control groups (0.95±0.30 mm vs. 1.00±0.33 mm, P > 0.05). CONCLUSION: Acromio-humeral and coraco-humeral distances are narrower than normal limits in patients with rotator cuff tears. In addition, coracoacromial arch angle may be a predisposing factor for rotator cuff tears.

Evaluation of hydrocephalus and other cerebrospinal fluid disorders with MRI: An update.

MRI is not only beneficial in the diagnosis of cerebrospinal fluid (CSF)-related diseases, but also aids in planning the management and post-surgery follow-up of the patients. With recent advances in MRI systems, there are many newly developed sequences and techniques that rapidly enable evaluation of CSF-related disorders with greater accuracy. For a better assessment of this group of disorders, radiologists should follow the developments closely and should be able to apply them when necessary. In this pictorial review, the role of MRI in the evaluation of hydrocephalus, CSF diversion techniques, and other CSF disorders is illustrated. Teaching Points • The 3D-SPACE seems to be most efficient technique for evaluation of hydrocephalus and ventriculostomy. • In complex cases, PC-MRI, 3D-heavily T2W, and/or CE-MRC images may prevent false results of 3D-SPACE.• MRI is beneficial in the diagnosis and management of hydrocephalus and other CSF-related diseases.

Cam impingement of the posterior femoral condyle in unicompartmental knee arthroplasty.

PURPOSE: There has been much emphasis on the importance of cam impingement, which is a cause of pain and knee hyperflexion restriction in unicompartmental knee arthroplasty (UKA). This study aimed to correlate cam impingement in the posterior femoral condyle with an α-angle showing the severity of the impingement. METHODS: The study groups consisted of 87 knees of 74 patients operated on with phase 3 medial Oxford UKA. Postoperatively, Group A (68 knees, 78.2 %) had no remnant of cam lesion; Group B (19 knees, 21.8 %) had cam lesion remnants. In Group C (18 knees, 20.7 %), which is a subgroup of Group A, cam lesions seen preoperatively were cleaned and not seen postoperatively. RESULTS: The mean increase in active flexion was 20.4° (± 7.3°) in Group A, 9.7° (± 6.1°) in Group B and 20.8° (± 7.3°) in Group C. The difference between Group A and Group B and between Group B and Group C was statistically significant (p < 0.001, p < 0.001). The mean decrease of α-angle was 11.2° (± 4.1°) in Group B, and 31.1° (± 3.4°) in Group C. The difference was statistically significant (p < 0.001). Mean Oxford Knee Scores were 24 preoperatively, 41 postoperatively in Group A; 22 preoperatively, 38 postoperatively in Group B; and 24 preoperatively, 40 postoperatively in Group C. The differences were not significant. CONCLUSIONS: Posterior condylar cam lesion is an impingement which limits hyperflexion and may be an early clinical finding prior to bearing dislocation and wear. The α-angle is a marker showing the severity of this cam lesion. This problem can be overcome using intraoperative fluoroscan views during cam excison and replacing the femoral component in 105° knee flexion.