Chandana Lall

Nonalcoholic fatty liver disease

OBJECTIVE The inflammatory subtype of nonalcoholic fatty liver disease, nonalcoholic steatohepatitis, is becoming one of the most important causes of chronic liver disease. In this article, we discuss the epidemiology, pathogenesis, and clinical and radiologic diagnosis of the subtypes of nonalcoholic fatty liver disease. CONCLUSION We discuss the current and evolving imaging tests in the evaluation of hepatic fatty content, inflammation, and fibrosis.

Urinary bladder cancer: Role of MR imaging

Urinary bladder cancer is a heterogeneous disease with a variety of pathologic features, cytogenetic characteristics, and natural histories. It is the fourth most common cancer in males and the tenth most common cancer in females. Urinary bladder cancer has a high recurrence rate, necessitating long-term surveillance after initial therapy. Early detection is important, since up to 47% of bladder cancer-related deaths may have been avoided. Conventional computed tomography (CT) and magnetic resonance (MR) imaging are only moderately accurate in the diagnosis and local staging of bladder cancer, with cystoscopy and pathologic staging remaining the standards of reference. However, the role of newer MR imaging sequences (eg, diffusion-weighted imaging) in the diagnosis and local staging of bladder cancer is still evolving. Substantial advances in MR imaging technology have made multiparametric MR imaging a feasible and reasonably accurate technique for the local staging of bladder cancer to optimize treatment. In addition, whole-body CT is the primary imaging technique for the detection of metastases in bladder cancer patients, especially those with disease that invades muscle.

New Concepts in Staging and Treatment of Locally Advanced Pancreatic Head Cancer

OBJECTIVE The objective of this article is to discuss the CT findings that guide surgeons in deciding the feasibility of tumor excision in patients with locally advanced pancreatic head cancers. CONCLUSION Vascular resection as an adjunct to pancreaticoduodenectomy is increasingly used in pancreatic head cancer. As a result, the imaging criteria to determine which patients are candidates for potentially curative resection are evolving.

Gastrointestinal complications of bariatric Roux-en-Y gastric bypass surgery

Obesity is rapidly becoming the most important public health issue in USA and Europe. Roux-en-Y gastric bypass is now established as the gold standard for treating intractable morbid or super obesity. We reviewed the imaging findings following this surgery in 234 patients. In this pictorial essay we present the CT and upper gastrointestinal contrast study appearances of the expected postoperative anatomy as well as a range of abdominal complications. The complications are classified into leaks, fistula and obstruction. Postoperative gastric outlet and small bowel obstruction can be caused by anastomotic stenosis, mesocolic tunnel stenosis, adhesions, stomal ulcer, obturation, intussusception and internal or external hernia. Small bowel obstruction may be of a simple, closed loop and/or strangulating type. The radiologist should be able to diagnose the type and possible cause of obstruction.

Fast fetal magnetic resonance imaging.

Fetal magnetic resonance imaging (MRI) can be used as a problem-solving tool when ultrasonic findings are equivocal. The role of fetal MRI has increased as obstetricians become aware of its potential and in utero therapy for anomalies becomes increasingly sophisticated. In this pictorial essay, we present a wide range of anomalies diagnosed or confirmed using MRI and discuss findings that help in the differential diagnosis.

Multidetector CT of Vascular Compression Syndromes in the Abdomen and Pelvis

Certain abdominopelvic vascular structures may be compressed by adjacent anatomic structures or may cause compression of adjacent hollow viscera. Such compressions may be asymptomatic; when symptomatic, however, they can lead to a variety of uncommon syndromes in the abdomen and pelvis, including median arcuate ligament syndrome, May-Thurner syndrome, nutcracker syndrome, superior mesenteric artery syndrome, ureteropelvic junction obstruction, ovarian vein syndrome, and other forms of ureteral compression. These syndromes, the pathogenesis of some of which remains controversial, can result in nonspecific symptoms of epigastric or flank pain, weight loss, nausea and vomiting, hematuria, or urinary tract infection. Direct venography or duplex ultrasonography can provide hemodynamic information in cases of vascular compression. However, multidetector computed tomography is particularly useful in that it allows a comprehensive single-study evaluation of the anatomy and resultant morphologic changes. Anatomic findings that can predispose to these syndromes may be encountered in patients who are undergoing imaging for unrelated reasons. However, the diagnosis of these syndromes should not be made on the basis of imaging findings alone. Severely symptomatic patients require treatment, which is generally surgical, although endovascular techniques are increasingly being used to treat venous compressions.

Bowel Complications Seen on CT After Pancreas Transplantation with Enteric Drainage

OBJECTIVE Bowel-related complications from pancreas transplantation account for much of the postsurgical morbidity. In a review of 98 pancreas transplant recipients, we found 19 (19.4%) with such complications. CONCLUSION The most common problems were small-bowel obstruction and anastomotic leaks. Adhesions and internal hernias accounted for most postoperative bowel obstructions.

Orthotopic liver transplantation: reversible Doppler US findings in the immediate postoperative period.

Orthotopic liver transplantation (OLT) is the only definitive treatment for irreversible acute liver failure and chronic liver disease. In the immediate postoperative period after OLT, patients are closely monitored with Doppler ultrasonography (US) to detect treatable vascular complications and ensure graft survival. The first postoperative Doppler US examination is performed fairly early on the first postoperative day, before surgical wound closure has been performed. The immediate postoperative images, obtained when the effects of surgery are very recent, often reveal an array of findings that may appear alarming but that tend to normalize within a few days and are compatible with changes related to the surgery itself. These findings include a starry-sky appearance of reperfusion hepatic edema, transient foci of increased echogenicity, pneumobilia, small fluid collections, perihepatic hematomas, pleural effusion, temporary elevation of hepatic arterial velocity, transient elevation of resistive index (RI), decreased RI with tardus parvus waveform, increased portal venous flow and mono- or biphasic waveforms of the hepatic veins. Most of these changes revert to normal in the first postoperative week; deterioration atypical of transient changes requires further evaluation.

Planting the seeds of success: CT‐guided gold seed fiducial marker placement to guide robotic radiosurgery

Fiducial marker (FM)‐guided stereotactic body radiation therapy (SBRT) allows for precise targeting and delivery of radiation to a tumor site. In this article, we briefly discuss SBRT, provide examples to describe CT‐guided FM placement to guide SBRT, and discuss some of the associated risks and benefits. This article serves as a pictorial review for body imagers and interventional radiologists who perform CT‐guided procedures and interpret diagnostic studies for oncology patients. CT‐guided FMs were placed in patients who were appropriate candidates for SBRT. One week following placement, patients underwent diagnostic CT and/or MR examinations in order to include the FM data in the development of a treatment plan. From October 2007–November 2009, a total of 89 patients were implanted with FMs. Sites of implantation included lung, liver, bone, chest and abdominal wall, and peritoneum/retroperitoneum. Complications included pneumothorax and FM migration. Twenty‐one patients (33%) with lung FM placement experienced at least a small pneumothorax and 6 patients (9%) required thoracostomy tubes. FM migration occurred in 5 patients (8%) with lung placement. SBRT provides a safer and more effective alternative to conventional radiotherapy, and CT‐guided FM implantation of tumor sites increases the precision of SBRT. Technical improvements in FM placement can limit the complications associated with the procedure and further enable highly localized tumor therapy.

Fetal magnetic resonance imaging.

Purpose of review Fetal magnetic resonance imaging is becoming more used in the evaluation of complex fetal abnormalities. Rapid advances in the technology and application of fetal magnetic resonance imaging necessitate a review of this subject. Recent findings Diffusion-weighted imaging, magnetic resonance spectroscopy and functional magnetic resonance imaging may allow assessment of fetal brain even before anatomical abnormalities are demonstrated. We discuss the uses of fetal magnetic resonance imaging in better assessment of pulmonary hypoplasia, congenital diaphragmatic hernia and renal anomalies. Summary The additional information from fetal magnetic resonance imaging, beyond that obtained by ultrasound, is invaluable in prenatal counseling, delivery planning and planning for pre- or postnatal intervention. As intrauterine and neonatal surgery evolve, so will the utilization of fetal magnetic resonance imaging.