Gurcan Erbay

Optimal b value in diffusion-weighted imaging for differentiation of abdominal lesions

To explore the optimal b value in diffusion‐weighted imaging (DWI) for differentiation of benign and malignant abdominal lesions.

Evaluation of malignant and benign renal lesions using diffusion-weighted MRI with multiple b values.

Background Limited data are available regarding the use of diffusion-weighted (DW) magnetic resonance imaging (MRI) with multiple b values for characterization of renal lesions. Purpose To demonstrate and compare the diagnostic performance of DW-MRI with multiple b values for renal lesion characterization. Material and Methods Sixty-three lesions (36 malignant, 27 benign) in 60 consecutive patients (48 men, 12 women; age 60 ± 12.5 years) with solid/cystic renal lesion diagnosed after MRI were included prospectively. Single-shot echo-planar DW abdominal MRI (1.5T) was obtained using seven b values with eight apparent diffusion coefficient (ADC) maps. Contrast-to-noise ratios (CNRs), signal intensities, lesion ADCs, and lesion/normal parenchyma ADC ratios were analyzed. Receiver-operating characteristic analysis was performed. Results The mean signal intensities of malignant lesions (at b0, 50, and 200s/mm2) were significantly lower than those of benign lesions (P < 0.05). The mean ADC values at all b value combinations of malignant lesions were significantly lower than those of benign lesions (P < 0.000), excluding the ADC value at b50 s/mm2. ADC with all b values could better distinguish between benign and malignant lesions. A 1.35 × 10−3 mm2/s threshold ADC value permitted this distinction with 85.2% sensitivity and 65.6% specificity. The lesion/normal parenchyma ADC ratio was more effective than the lesion ADC. Conclusion In addition to the ADC value, the signal intensity curve on DW images using multiple b values could be helpful for differentiation of malignant and benign renal lesions.

Chest radiography and CT findings in patients with the 2009 pandemic (H1N1) influenza.

PURPOSE To present chest radiography and thoracic computed tomography (CT) findings for patients with pandemic influenza A (H1N1) from November-December 2009 and to explore any differences compared to previously reported imaging findings. MATERIALS AND METHODS Fifty-two hospitalized patients with pandemic influenza (H1N1) were included in the study. All of the patients underwent chest radiography, and 28 patients were also evaluated by thoracic CT. Group 1 comprised 24 (46%) patients with no identified risk factors for H1N1 influenza infection. Group 2 comprised the remaining 28 (54%) patients with identified risk factors. The distribution of lung involvement, consolidation, ground-glass opacity (GGO), lymph nodes, and pleural effusion were evaluated. RESULTS Abnormal findings were observed in 85% of the patients. Bilateral lung involvement was present in 80% of the patients. The most common finding was a mixture of GGO and air-space consolidation. Lower zone predominance occurred in 89% of group 1 and 85% of group 2 patients. The involvement was observed most frequently in the peripheral and central perihilar areas of the lung in 80% of the patients. The extent of disease was greater in group 2 patients with the involvement of three or more lung zones in 62% of the patients. CONCLUSION The most common imaging finding for lung involvement was a mixture of air-space consolidation and GGO with a patchy pattern and lower/middle zone predominance. Pulmonary involvement of the disease was more extensive than that described in previous reports.

Optimization of b value in diffusion‐weighted MRI for characterization of benign and malignant gynecological lesions

To explore the optimal b value in diffusion‐weighted (DW)‐MRI for differentiation of benign and malignant gynecological lesions.

Treatment response evaluation using the mean apparent diffusion coefficient in cervical cancer patients treated with definitive chemoradiotherapy.

To investigate the pre‐ and posttreatment mean apparent diffusion coefficient (ADCmean) of cervical cancer tumors treated with definitive chemoradiotherapy (CRT) and evaluate their correlation with recurrence and survival rates.

Spontaneous giant splenic hydatid cyst rupture causing fatal anaphylactic shock: A case report and brief literature review

Hydatid disease is a parasitic infection characterized by cyst formation in any organ, although the liver and lungs are most commonly involved. Hydatid disease of the spleen is uncommon, representing <8% of all human hydatid diseases. Splenic hydatid cysts usually coexist with liver hydatid cysts (secondary form), although the spleen is the primary location (primary form) in some cases. The clinical signs and symptoms of splenic hydatid cysts depend on their size, relationship with adjacent organs, and complications. One of the complications of splenic hydatid cysts is cyst rupture either after trauma or spontaneously as a result of increased intracystic pressure. These cysts may rupture into a hollow organ, through the diaphragm into the pleural cavity, or directly into the peritoneal cavity. A splenic hydatid cyst that ruptures into the peritoneal cavity may cause complications, including signs of peritoneal irritation, urticaria, anaphylaxis, and death, as in our case. Therefore, a hydatid cyst rupture requires both emergency surgery and careful postoperative care. In this study, we present a case of a giant splenic hydatid cyst that ruptured into the peritoneal cavity without any trauma. A review of cases reported in the English literature about splenic hydatid cyst perforation is also discussed.

Predicting tumor recurrence in patients with cervical carcinoma treated with definitive chemoradiotherapy: value of quantitative histogram analysis on diffusion-weighted MR images:

Background Further research is required for evaluating the use of ADC histogram analysis in more advanced stages of cervical cancer treated with definitive chemoradiotherapy (CRT). Purpose To investigate the utility of apparent diffusion coefficient (ADC) histogram derived from diffusion-weighted magnetic resonance images in cervical cancer patients treated with definitive CRT. Material and Methods The clinical and radiological data of 50 patients with histologically proven cervical squamous cell carcinoma treated with definitive CRT were retrospectively analyzed. The impact of clinicopathological factors and ADC histogram parameters on prognostic factors and treatment outcomes was assessed. Results The mean and median ADC values for the cohort were 1.043 ± 0.135 × 10−3 mm2/s and 1.018 × 10−3 mm2/s (range, 0.787–1.443 × 10−3 mm2/s). The mean ADC was significantly lower for patients with advanced stage (≥IIB) or lymph node metastasis compared with patients with stage <IIB or no lymph node metastasis. The mean ADC, 75th percentile ADC (ADC75), 90th percentile ADC (ADC90), and 95th percentile ADC (ADC95) were significantly lower in patients with tumor recurrence compared with patients without recurrence. In multivariate analysis, tumor size, ADC75 and ADC95 were independent prognostic factors for both overall survival and disease-free survival. Conclusion ADC histogram parameters could be markers for disease recurrence and for predicting survival outcomes. ADC75, ADC90, and ADC95 of the primary tumor were significant predictors of disease recurrence in cervical cancer patients treated with definitive CRT.

Uterine perforation during 3-dimensional image-guided brachytherapy in patients with cervical cancer: Baskent University experience.

Objectives This study aimed to determine the incidence and characteristics of uterine perforation at our department using 3-dimensional computed tomography (CT)–based brachytherapy (BRT). The characteristics of the patients presenting with perforation and impact of the perforation on the treatment course were also analyzed. Materials and Methods The clinical and radiologic data of 200 patients with biopsy-proven cervical cancer treated using CT-based BRT were retrospectively evaluated. All patients had undergone tandem-based intracavitary BRT, and 67 patients had undergone magnetic resonance imaging (MRI) before BRT. Results Of the 200 patients, 17 (8.5%) had uterine perforation. Of the 626 applications with CT images, 30 (4.8%) resulted in uterine perforation. The median age of patients with perforation was higher (68 years; range, 44–89 years) than that of the patients without perforation (59 years; range, 21–87 years), and the mean (SD) tumor size at diagnosis was larger in patients with perforation (7.0 [1.5] cm) than in patients without perforation (5.0 [1.5] cm). The most frequent perforation site was the posterior uterine wall (8 patients), followed by the fundus (5 patients) and anterior wall (4 patients). Of the 7 patients with a retroverted uterus, 4 had uterine perforation during BRT. In 67 patients with MRI delivered before BRT, only 3 (4%) had uterine perforation, and 2 of the 3 patients with uterine perforation had a retroverted uterus. However, of the 133 patients with no MRI evaluation before BRT, 14 (11%) had uterine perforation. No life-threatening complications or signs of intraperitoneal tumor cell seeding were observed. Conclusions Older age, larger tumors, a retroverted uterus, and a stenotic cervical os were all predisposing factors for uterine perforation during BRT. Preoperative MRI is a feasible and safe method to decrease the risks of uterine perforation and could be used preoperatively in centers where intraoperative ultrasonography is not used in routine practice.

Retroperitoneal Malignant Fibrous Histiocytoma Can Mimic a Hydatid Cyst

Malignant fibrous histiocytoma is the second most common soft-tissue sarcoma in adults. After the extremities, the retroperitoneal space is the second most common site of this tumor. A 50-year-old man presented with a right retroperitoneal, thick-walled, cystic multilocular mass measuring 10 × 10 cm that was thought to be a type CE 5 hydatid cyst preoperatively. However, the postoperative histopathology did not agree with the radiological findings and instead showed a malignant fibrous histiocytoma. The computed tomography and ultrasound/Doppler ultrasound findings of this retroperitoneal mass mimicked a type CE 5 hydatid cyst. We present this case because the surgical management of these two lesions differs and misdiagnosis can be problematic.

Utility of Diffusion-Weighted MRI to Detect Changes in Liver Diffusion in Benign and Malignant Distal Bile Duct Obstruction: The Influence of Choice of b-Values

Purpose The study sought to evaluate the potential of diffusion-weighted magnetic resonance imaging to detect changes in liver diffusion in benign and malignant distal bile duct obstruction and to investigate the effect of the choice of b-values on apparent diffusion coefficient (ADC). Methods Diffusion-weighted imaging was acquired with b-values of 200, 600, 800, and 1000 s/mm2. ADC values were obtained in 4 segments of the liver. The mean ADC values of 16 patients with malignant distal bile duct obstruction, 14 patients with benign distal bile duct obstruction, and a control group of 16 healthy patients were compared. Results Mean ADC values for 4 liver segments were lower in the malignant obstruction group than in the benign obstruction and control groups using b = 200 s/mm2 (P < .05). Mean ADC values of the left lobe medial and lateral segments were lower in the malignant obstruction group than in the benign obstructive and control groups using b = 600 s/mm2 (P < .05). Mean ADC values of the right lobe posterior segment were lower in the malignant and benign obstruction groups than in the control group using b = 1000 s/mm2 (P < .05). Using b = 800 s/mm2, ADC values of all 4 liver segments in each group were not significantly different (P > .05). There were no correlations between the ADC values of liver segments and liver function tests. Conclusion Measurement of ADC shows good potential for detecting changes in liver diffusion in patients with distal bile duct obstruction. Calculated ADC values were affected by the choice of b-values.