Selim Doganay

Diagnostic performance of diffusion-weighted MRI in the detection of nonpalpable undescended testes: comparison with conventional MRI and surgical findings.

OBJECTIVE The aim of this feasibility study was to evaluate the role of diffusion-weighted MRI in the evaluation of nonpalpable undescended testes. MATERIALS AND METHODS Thirty-six boys with undescended testes underwent preoperative abdominal and pelvic MRI to identify the location of the testes. MRI included free-breathing diffusion-weighted imaging (DWI) with b values of 50, 400, and 800 s/mm(2), a T1-weighted turbo spin-echo sequence, and a T2-weighted fat-suppressed turbo spin-echo sequence. After laparoscopic examinations, two observers independently reviewed the preoperative images. The DW images alone were reviewed first, followed by the conventional MR images alone and the conventional MR and the DW images together. The laparoscopic and MRI findings were compared. Sensitivity, specificity, and accuracy in the identification of nonpalpable undescended testes were calculated for DWI, conventional MRI, and the combination of DWI and conventional MRI. RESULTS The combination of DWI and conventional MRI was the most sensitive and most accurate technique. Observer 1 found 31 undescended testes, and observer 2, 30 testes with this technique. Sensitivity was 0.91 and 0.88 for observers 1 and 2, and accuracy was 0.92 and 0.86. With DWI alone, observer 1 located 30 testes, and observer 2, 28 testes (sensitivity, 0.88 and 0.82; accuracy, 0.86 and 0.81). Using conventional MRI alone, both observers located 29 testes (sensitivity, 0.85; accuracy, 0.86 and 0.84). The accuracy of locating testes was superior with the combination of DWI and conventional MRI for both observers (accuracy, 0.92 and 0.86). An intraabdominal atrophic testis managed by laparoscopic orchiectomy was found by neither observer with DWI or with conventional MRI. CONCLUSION Use of DWI with a high b value yields information that complements conventional MRI findings, improving identification and location of nonpalpable undescended testes. We recommend the use of conventional MRI in addition to DWI to increase the preoperative sensitivity and accuracy of identifying and locating nonpalpable testes.

Comparison of peritoneal tumor imaging using conventional MR imaging and diffusion-weighted MR imaging with different b values

PURPOSE The aim of this study was to evaluate the utility of DW MRI with two different b values in identifying peritoneal tumors in oncology patients. MATERIALS AND METHODS Nineteen patients with known malignancy underwent abdominal and pelvic MRI before surgery. MRI included free-breathing DWI with b values of 400 and 800 s/mm2, T1-weighted fat-suppressed spoiled gradient-echo, T2-weighted fat-saturated turbo spin-echo, and 5-min delayed gadolinium-enhanced imaging. Two observers reviewed images for peritoneal tumors at ten anatomic sites within consensus. The results of laparatomy and histopathological evaluation were compared with MRI results. Sensitivity, specificity, and accuracy of identifying peritoneal metastases were calculated for conventional MRI, combined DWI with a b value of 400 s/mm2 and conventional MRI, and combined DWI with a b value of 800 s/mm2 and conventional MRI by consensus of two observers. RESULTS One-hundred and twenty-five peritoneal metastasis sites were confirmed by surgical and histopathological findings. Conventional MRI alone identified 72 peritoneal metastases (sensitivity, 0.58; specificity, 0.87; accuracy, 0.67). Combined DWI with a b value of 400 s/mm2 and conventional MRI revealed 106 peritoneal metastases (sensitivity, 0.85; specificity, 0.88; accuracy, 0.85). Finally, combined DWI with a b value of 800 s/mm2 and conventional MRI revealed 103 peritoneal metastases (sensitivity, 0.83; specificity, 0.94; accuracy, 0.86). CONCLUSION DWI with a high b value provides complementary information that can improve the detection of peritoneal tumors when combined with conventional MRI. We recommend combined MRI and DWI with a high b value for increasing the sensitivity and accuracy of the preoperative detection of peritoneal tumors.

The role of MRS in the differentiation of benign and malignant soft tissue and bone tumors

OBJECTIVE The aim of our study was to investigate the value of choline in the discrimination of benign and malignant soft tissue and bone tumors. MATERIALS AND METHODS The study group consisted of thirty subjects with bone or soft tissue tumors larger than 1.5 cm in diameter. The experiments were performed in a 1.5T MR scanner. Coils were selected according to specific locations. A single-voxel MRS was performed for three different TE (time to echo) (31, 136, 272 ms). The volume of interest was positioned on the brightest enhancement. The presence of a cholin peak on at least 2 of these spectrums was considered as the marker of malignancy. The sensitivity, specificity and accuracy of the MRS in the detection and diagnosis of malignant lesions were calculated. The reproducibility of MRS and histopathological results were tested with kappa statistics. RESULTS Histopathologically, 18 (60%) of the lesions were classed as malignant whereas 12 (40%) were classed as benign. With MRS, 15 (50%) of these lesions were classed as malignant and 15 (50%) as benign. Two patients who were found spectroscopically to have malignant tumors were shown histopathologically to have benign types. Five patients with an MRS showing a benign type were classed with malignant types in histopathological examinations. MRS had a sensitivity rate of 72.2%, specificity of 83.3%, and an accuracy rate of 76.6% in detecting malignant bone and soft tissue tumors. The interrater reliability of both techniques had a kappa value of 0.533. CONCLUSIONS MRS may help in the differentiation of benign and malignant soft tissue and bone tumors.

Clinical situations in which coronary CT angiography confers superior diagnostic information compared with coronary angiography

In this review, we aimed to outline the clinical and pathological conditions for which multidetector computed tomography coronary angiography (MDCT-CA) should be the preferred method because of its advantages over conventional coronary angiography (CCA). A consistent body of literature suggests that MDCT-CA is more than just complementary to CCA and that it provides more valuable diagnostic information in certain clinical situations, such as complex coronary artery variations, aorto-ostial lesions, follow-up of bypass grafts, myocardial bridging, coronary artery fistulas, aortic and coronary artery dissections, and cases in which the coronary ostia cannot be cannulated by a catheter because of massive atherosclerosis or extremely tortuous vascular structures.

Hepatic arterial mapping by multidetector computed tomographic angiography in living donor liver transplantation.

Purpose: Our aims were to present the hepatic arterial variations that were detected with computed tomographic angiography (CTA) and confirmed by operation in living liver donors and to emphasize the usefulness of CTA in the assessment of hepatic arterial anatomy. Materials and Methods: The donors of 100 patients (46 women and 54 men) who had undergone a living donor liver transplantation in a (blinded) hospital between July 2004 and June 2007 were evaluated. The age of the donors ranged from 18 to 63 years (mean, 39 years). The CTA images obtained by a 16-slice multidetector CT before the transplantation procedure were retrospectively evaluated for arterial variations, and the results were compared with the results of the operation. Results: In 59 donors (59%), classic hepatic arterial anatomy was observed. In the remaining 41 donors (41%), various arterial variations were determined. In 11 of the donors (11%), variations were not compatible with the description of Michels classification. In all of our patients, CTA findings were confirmed with operational findings. Our complication rate was 1%. Only 1 of the patients who had undergone the transplantation developed hepatic arterial thrombus, and the remaining 99 patients had no arterial complications. Conclusions: The course of the vascular structures before live donor liver transplantation is essential for planning and success of the operation. Our study showed that multidetector CTA can be used successfully in hepatic artery imaging of liver transplantation donors as a noninvasive method.

Determination of lingual vascular canals in the interforaminal region before implant surgery to prevent life-threatening bleeding complications

OBJECTIVES Profuse hemorrhage and airway obstruction may occur during or after the implant surgery in the interforaminal region. The prevention from this complication requires identifying the location of the mandibular lingual vascular canals (MLVCs). The purpose of this study was to evaluate the anatomical variations of MLVCs and to determine the safety margins for implant placement in interforaminal region. MATERIALS AND METHODS Computer tomography (CT) images of 200 consecutive patients were reexamined retrospectively by a radiologist and a maxillofacial surgeon to evaluate the presence of the MLVCs entering the mandible. The diameter and the number of the canals, the distance between the entrance of the canal and mandibular midline, and the height of the entrances of the canals from the inferior mandibular margin were measured. RESULTS Two hundred and thirty-six median lingual canals (MLCs) and 159 lateral lingual canals (LLCs) were found in 200 patients. Significant differences were found between the number of lingual canals in the midline and canine regions (P < 0.001). CONCLUSION There is a potential risk of complications due to the injuries of the vessels entering the lingual cortical bone through a number of bone canals during implant placement in the interforaminal region.

Susceptibility-Based Differentiation of Intracranial Calcification and Hemorrhage in Pediatric Patients.

Differential diagnosis of intracranial hemorrhage versus calcification on conventional magnetic resonance images (MRIs) is often challenging. Although computed tomography (CT) confirms calcification, phase information obtained during susceptibility-weighted imaging can be useful in distinguishing between 2 pathologies. Fourteen patients previously diagnosed to have hemorrhage or calcification with imaging were included in the study retrospectively. Phase shift values of hemorrhage and calcification were compared by using Student t test. The pathologies identified were tuberous sclerosis, Sturge-Weber syndrome, craniopharyngioma, congenital cytomegalovirus, subependymal hemorrhages, and hemorrhagic microembolic infarction. Calcifications appeared hypointense whereas hemorrhages were hyperintense on phase maps (left-handed magnetic resonance system). Statistical comparison of phase shift values yielded significant difference between hemorrhage versus calcification (P < .01). Phase maps were found to offer valuable data to differentiate 2 pathologies when used complementary to conventional magnetic resonance images. Considering the relatively higher risks of radiation exposure in children, susceptibility-weighted imaging with phase maps may help to waive radiation exposure from CT.

Silent brain infarcts in two patients with zeta chain-associated protein 70 kDa (ZAP70) deficiency

Zeta-chain associated protein 70 kDa deficiency (ZAP70) is a form of severe combined immunodeficiency (SCID). It is caused by defects in the signaling pathways associated with T-lymphocyte activation. ZAP70 deficiency is characterized by a marked reduction in peripheral CD8+ T-cells. In this report, we described two patients with ZAP70 deficiency who presented with recurrent infections, lung tuberculosis (TBC), congenital nephrotic syndrome (CNS), and silent brain infarcts (SBIs) as a common feature. The first patient initially presented with recurrent infections and TBC as in a classic SCID patient. At the age of 4, he was interned with febrile seizure. Cranial magnetic resonance imaging (MRI) showed SBIs. The second patient, an 8-month-old boy, presented with congenital nephrotic syndrome caused by cytomegalovirus (CMV) and he had also SBIs.

Arterial bending angle and wall morphology correlate with slow coronary flow: Determination with multidetector CT coronary angiography

BACKGROUND AND PURPOSE The purpose of this study was to assess angulations and vessel wall morphology that could lead to bending head loss in the RCA and LMCA arteries of patients with slow coronary flow (SCF) evaluated by MDCT coronary angiography. METHODS The study involved 51 patients (45 males, mean age: 59.6 years) who were diagnosed with SCF by coronary angiography. Diagnosis of SCF was based on thrombolysis in myocardial infarction (TIMI) frame count. Fifty-one patients with absence of slow flow were selected as the control group. The angulations of the main coronary arteries with the aorta were measured from the axial images obtained through MDCT coronary angiography, and the findings were recorded. In addition, the coronary artery walls of these patients were evaluated. For statistical analysis, SPSS for Windows 10.0 (SPSS Inc., Chicago, IL) was used. For comparisons of the angles, either independent samples t test or the Mann-Whitney U test was used where appropriate. RESULTS The results of the study indicated that 38 patients had SCF in the LAD. Comparisons of patients with SCF with the controls revealed that in the patients with SCF, the mean angle of the LMCA with the aorta (40.9±20.5°) was statistically significantly smaller than the mean angle of the LMCA with the aorta in the control cases (71.8±11°). In 12 patients, slow flow was detected in the RCA. Those with slow flow in the RCA had significantly smaller angles (mean: 33.2±20.4°) than the other cases (mean: 78.9±10.7°). CONCLUSION A small angle of origin of the main coronary arteries from the aorta, measured on MDCT examinations is correlated with slow blood flow in those vessels, as calculated by the TIMI frame count in catheter coronary angiography.

Pituitary duplication: a rare cause of precocious puberty.

The duplication of pituitary gland and stalk is a rare malformation. It is first described by Ahlfeld in 1880 [1] and about 40 patients have been described to date [1–22]. An isolated duplication is very rare [2]. Most of the cases reported were associated with other anomalies such as agenesis/ hypoplasia of corpus callosum, cerebellar hypoplasia, hydrocephalus, absent olfactory bulbs and/or tracts, oropharengeal masses including teratomas, and various midline defects [3]. These associated malformations usually were reported to lead to death in infancy [4]. In literature, of those cases surviving beyond infancy, 11 were females and central precocious puberty was seen in seven (including the present case) [5] (Table 1). The pathogenesis of pituitary duplication and its relation to precocious puberty has not been clarified yet.