Ali Devrim Karaosmanoglu

CT angiography of the renal arteries and veins: normal anatomy and variants.

Conventional angiography has long been regarded as gold standard imaging modality for evaluation of the renal vasculature. Introduction of multidetector computed tomography (MDCT) angiography had a groundbreaking impact on evaluation of the renal vessels and is gradually replacing conventional angiography as standard imaging. Herein, we review and illustrate the normal and variant anatomy of renal vessels with special emphasis on imaging protocols and reconstruction techniques in MDCT.

CT and MRI of Aortic Coarctation: Pre- and Postsurgical Findings

OBJECTIVE. The purpose of this article is to summarize the roles of CT and MRI in the diagnosis and follow-up of patients with aortic coarctation. CONCLUSION. Aortic coarctation is a common congenital heart disease accounting for approximately 6-8% of congenital heart defects. Despite its deceptively simple anatomic presentation, it is a complex medical problem with several associated anatomic and physiologic abnormalities. CT and MRI may provide very accurate information of the coarctation anatomy and other associated cardiac abnormalities.

The role of bilateral inferior petrosal sinus sampling in the diagnostic evaluation of Cushing syndrome.

Bilateral inferior petrosal sinus sampling is the gold standard diagnostic assay in identifying the pituitary source of adrenocorticotropic hormone secretion in Cushing syndrome. The noninvasive assays used in the workup of Cushing syndrome are often misleading or ambiguous, yielding sensitivities of up to only 80%. Inferior petrosal sinus sampling, however, is highly accurate and safe when performed in experienced centers. We review here the historical and technical details of the procedure, with emphasis on the relevant anatomy and a discussion of possible rare complications.

Applications of PET-CT in patients with esophageal cancer.

Although esophageal cancer is not among the common cancers as prostate, lung, breast, or colon malignancies, it has an exceedingly high mortality rate, with its incidence close to the cancer-specific mortality. Currently, the only potentially curative treatment is surgery. Unfortunately, surgical treatment is extensive and may have significant morbidity and mortality related with it. Given these facts, selection of patients who are amenable to surgical treatment is of utmost importance. Conventional morphology based cross-sectional imaging modalities are extremely helpful for pre-surgical evaluation and follow-up of these patients, however, they have very wellknown limitations. Positron emission tomography-computed tomography (PET-CT) is a relatively new, highly promising molecular imaging technique which may overcome some of the fundemental limitations of these conventional cross-sectional modalities in the pre-surgical evaluation and follow-up of these patients. In this review, we evaluated the applications of PET-CT in patients with esophageal cancer.

Mesenteric Arterial Variations Detected at MDCT Angiography of Abdominal Aorta

OBJECTIVE The purposes of this essay are to outline MDCT angiographic techniques for the evaluation of the mesenteric arterial vasculature and to review anatomic variants depicted on MDCT angiograms. CONCLUSION MDCT angiography has distinct advantages over conventional angiography in imaging of the mesenteric arterial vasculature.

Imaging findings of renal toxicity in patients on chronic lithium therapy.

Lithium salts are the mainstay of treatment of bipolar disorder. However, the therapeutic index of lithium is narrow, and severe side effects may be seen. Nephrotoxicity is the most important side effect, which may progress to chronic renal failure. In this pictorial essay, we present ultrasonography, computed tomography, and magnetic resonance imaging findings of renal toxicity secondary to chronic lithium use. We believe that imaging could be extremely helpful for the evaluation of renal toxicity and may even detect preclinical stages of renal parenchymal injury. A combination of different imaging modalities may help clarify findings detected on one modality.

Ultralow-Dose Abdominal Computed Tomography: Comparison of 2 Iterative Reconstruction Techniques in a Prospective Clinical Study.

Purpose To assess lesion detection and image quality of ultralow-dose (ULD) abdominal computed tomography (CT) reconstructed with filtered back projection (FBP) and 2 iterative reconstruction techniques: hybrid-based iDose, and image-based SafeCT. Materials and Methods In this institutional review board–approved ongoing prospective clinical study, 41 adult patients provided written informed consent for an additional ULD abdominal CT examination immediately after standard dose (SD) CT exam on a 256-slice multidetector computed tomography (iCT, Philips-Healthcare). The SD examination (size-specific dose estimate, 10 ± 3 mGy) was performed at 120 kV with automatic exposure control, and reconstructed with FBP. The ULD examination (1.5 ± 0.4 mGy) was performed at 120 kV and fixed tube current of 17 to 20 mAs/slice to achieve ULD radiation dose, with the rest of the scan parameters same as SD examination. The ULD data were reconstructed with (a) FBP, (b) iDose, and (c) SafeCT. Lesions were detected on ULD FBP series and compared to SD FBP “reference-standard” series. True lesions, pseudolesions, and missed lesions were recorded. Four abdominal radiologists independently blindly performed subjective image quality. Objective image quality included image noise calculation and noise spectral density plots. Results All true lesions (n, 52: liver metastases, renal cysts, diverticulosis) in SD FBP images were detected in ULD images. Although there were no missed or pseudolesions on ULD iDose and ULD SafeCT images, appearance of small low-contrast hepatic lesions was suboptimal. The ULD FBP images were unacceptable across all patients for both lesion detection and image quality. In patients with a body mass index (BMI) of 25 kg/m2 or less, ULD iDose and ULD SafeCT images were acceptable for image quality that was close to SD FBP for both normal and abnormal abdominal and pelvic structures. With increasing BMI, the image quality of ULD images was deemed unacceptable due to photo starvation. Evaluation of kidney stones with ULD iDose/SafeCT images was found acceptable regardless of patient size. Image noise levels were significantly lower in ULD iDose and ULD SafeCT images compared to ULD FBP (P < 0.01). Conclusions Preliminary results show that ULD abdominal CT reconstructed with iterative reconstruction techniques is achievable in smaller patients (BMI ⩽ 25 kg/m2) but remains a challenge for overweight to obese patients. Lesion detection is similar in full-dose SD FBP and ULD iDose/SafeCT images, with suboptimal visibility of low-contrast lesions in ULD images.

Unusual benign solid neoplasms of the kidney: cross-sectional imaging findings.

Kidney neoplasms are common diseases with varying prognoses depending on the subtype of the tumor. The most common solid lesion of the kidney is renal cell carcinoma, and the treatment is typically surgical removal. With increasing use of cross-sectional imaging in the last two decades, the detection of renal lesions has significantly increased, especially in asymptomatic patients who are scanned for other reasons. In this article, we present the imaging findings of rare solid benign primary kidney neoplasms including renal leiomyoma, reninoma, carcinoid tumor, metanephric adenoma, solitary fibrous tumor of the kidney, lipomatous hemangiopericytoma of the kidney, renal schwannoma, inflammatory myofibroblastic tumor of the kidney, extramedullary hematopoiesis in the kidney, and extranodal renal Rosai-Dorfman disease. Accurate preoperative or prebiopsy diagnoses of these lesions are unusual; however, informed radiologists may sometimes be able to favorably change the patient management and treatment.

Imaging of hepatobiliary involvement in sarcoidosis.

Abstract Sarcoidosis is mainly a disease of the respiratory system; however, several other organ systems may be affected in the course of the disease. Liver is one of the most frequently affected organs in the setting of sarcoidosis after lungs and lymph nodes. Microscopic hepatic involvement is common in these patients but is mostly clinically silent. However, in a significant portion of these patients, macroscopic findings can be detected in the course of the disease, and these findings may easily be confused with other benign and malignant conditions of the liver. The purposes of this article are to briefly summarize the clinical findings and the underlying pathophysiology of sarcoidosis and detailed presentation of the radiologic findings of hepatic involvement in this disease. We subgrouped the imaging findings based on the location and the radiologic appearance of the hepatic involvement. We tried to provide images that would enable the readers to link the imaging findings with the underlying pathology and clinical symptoms.

Magnetic Resonance Imaging of Liver Metastasis

Liver magnetic resonance imaging (MRI) is becoming the gold standard in liver metastasis detection and treatment response assessment. The most sensitive magnetic resonance sequences are diffusion-weighted images and hepatobiliary phase images after Gd-EOB-DTPA. Peripheral ring enhancement, diffusion restriction, and hypointensity on hepatobiliary phase images are hallmarks of liver metastases. In patients with normal ultrasonography, computed tomography (CT), and positron emission tomography (PET)-CT findings and high clinical suspicion of metastasis, MRI should be performed for diagnosis of unseen metastasis. In melanoma, colon cancer, and neuroendocrine tumor metastases, MRI allows confident diagnosis of treatment-related changes in liver and enables differential diagnosis from primary liver tumors. Focal nodular hyperplasia-like nodules in patients who received platinum-based chemotherapy, hypersteatosis, and focal fat can mimic metastasis. In cancer patients with fatty liver, MRI should be preferred to CT. Although the first-line imaging for metastases is CT, MRI can be used as a problem-solving method. MRI may be used as the first-line method in patients who would undergo curative surgery or metastatectomy. Current limitation of MRI is low sensitivity for metastasis smaller than 3mm. MRI fingerprinting, glucoCEST MRI, and PET-MRI may allow simpler and more sensitive diagnosis of liver metastasis.