John M. Kirby

Arterial Embolization for Primary Postpartum Hemorrhage

PURPOSE To evaluate the efficacy and safety of arterial embolization (AE) for treatment of primary postpartum hemorrhage (PPH), and the factors associated with clinical success. MATERIAL AND METHODS A retrospective analysis of all patients undergoing AE for primary PPH at three institutions (N = 43) from 1996 through 2007 was conducted. Patients with an antepartum diagnosis of invasive placenta were excluded from the study. Mean patient age was 31 years +/- 5 (range, 21-40 y). Eighteen women (42%) were primiparous. Delivery details, transfusion requirements, hematology and coagulation results, embolization details, and clinical outcomes were collected. Clinical success was defined as cessation of bleeding without the need for repeat embolization, laparotomy, or hysterectomy after embolization; or death. The Fisher exact test was used to analyze nonparametric data. RESULTS The clinical success rate was 79% (n = 34). Four patients underwent successful repeat embolization. Two of 35 patients who had not undergone hysterectomy before embolization underwent hysterectomy for continued bleeding (without repeat embolization). One underwent hysterectomy 2 weeks after AE for uterine necrosis. One of eight patients who had undergone hysterectomy before AE required a laparotomy for a large retroperitoneal hematoma, and one patient died from cerebral anoxia secondary to hypotension despite repeat embolization. Clinical success was not related to mode of delivery, cause of PPH, transfusion requirements, time from delivery to embolization, or hysterectomy before AE (P > .05). Patients with active extravasation visualized angiographically were more likely to require repeat embolization (five of 13 [38%] vs 0 of 30 without extravasation; P < .01). CONCLUSIONS AE for primary PPH is safe and effective. Repeat embolization may be necessary in patients with active extravasation on angiography.

Can CT Replace MRI in Preoperative Assessment of the Circumferential Resection Margin in Rectal Cancer

The surgical circumferential resection margin in total mesorectal excision surgery is defined by the relationship of the tumor to the mesorectal fascia. Patients with anticipated tumor invasion of the mesorectal fascia receive neoadjuvant therapy to downstage/downsize the tumor and to obtain tumor-free resection margins. Tumor relationship to the mesorectal fascia is accurately determined by MRI. Compared with MRI, multidetector-row computed tomography is more widely available, faster, less costly, and provides the ability to simultaneously assess the liver, peritoneum, and retroperitoneum for metastases. PURPOSE: The objective of this study was to compare the accuracy of multidetector-row CT with conventional MRI in diagnosis of rectal cancer invasion of the mesorectal fascial envelope. MATERIALS AND METHODS: During a 2-year period, all patients were enrolled in this study who had biopsy-proven rectal carcinoma and were referred, as a part of the routine preoperative staging workup, for a CT scan of the abdomen and pelvis and also an MRI of the pelvis. All examinations were reviewed independently by 2 radiologists who were blinded from one another, from the findings of the other modality, and from clinical information. Both observers were dedicated abdominal radiologists who are experienced in reading pelvic CT and MRI. Categorical agreement between MRI and multidetector-row CT for all the evaluated parameters of the tumor position, mesorectal fascia, and lymph nodes, as well as the interobserver agreement between CT and MRI, was determined by the intraclass correlation weighted kappa statistic to measure the data sets consistency. RESULTS: Among the studys 92 patients, the tumor characteristics suggested by multidetector-row CT agreed with those of MRI, with a weighted &kgr; ranging from 0.488 to 0.748 for the first reader and 0.577 to 0.800 for the second reader. Interobserver agreement ranged from 0.506 to 0.746. Agreement regarding mesorectal fascia characteristics differed significantly between multidetector-row CT and MRI, depending on the level of assessment. In the distal rectum, agreement was 0.207 for the first reader and 0.385 for the second reader. In the mid rectum, agreement was 0.420 and 0.527, respectively, and in the proximal rectum agreement was 0.508 and 0.520. Interobserver agreement was 0.737 at the distal level and 0.700 at the mid and proximal levels. Agreement regarding measurement of the distance from the tumor to the mesorectal fascia was 0.425 for the first reader and 0.723 for the second reader, with interobserver agreement of 0.766. Agreement in assessment of the number of lymph nodes ranged from 0.743 to 0.787 for the first reader and 0.754 to 0.840 for the second reader. Interobserver agreement ranged from 0.779 to 0.841. Agreement in assessment of the size of the lymph nodes ranged from 0.540 to 0.830 for the first reader and 0.850 to 0.940 for the second reader. Interobserver agreement ranged from 0.900 to 0.920. Agreement in assessment of the distance from nodes to the mesorectal fascia was 0.320 for the first reader and 0.401 for the second reader, with interobserver agreement of 0.950. CONCLUSION: The results of this study differ from previously published data by demonstrating substantial agreement between readers in multidetector-row CT assessment of the tumor, mesorectal fascia, and lymph nodes. With the exceptions of mesorectal fascia in the distal rectum and the distance from the nodes to mesorectal fascia, other evaluated parameters were assessed with moderate and substantial agreement between multidetector-row CT and MRI. However, our findings suggest that multidetector-row CT does not correlate well enough with MRI findings to replace it in rectal cancer staging.

Hürthle Cell Neoplasms of the Thyroid : Sonographic Appearance and Histologic Characteristics

Objective. The purpose of this study was to determine the sonographic features of Hürthle cell neoplasms (HCNs) of the thyroid. Methods. We retrospectively analyzed the sonographic appearance of 15 histologically proven HCNs in 15 patients aged 16 to 70 years (mean age, 44 years). Sonographic features that were reviewed included the size and echogenicity of the tumors, the presence of cystic areas or calcifications, and detectable blood flow on color Doppler imaging. Correlation of sonographic findings with pathologic results was performed. Results. The tumors ranged from 0.4 to 7 cm in diameter, but most were less than 3 cm in diameter. Four (27%) of the 15 tumors were homogeneously hypoechoic. Two tumors (13%) were predominantly hypoechoic with isoechoic areas to thyroid parenchyma. Two (13%) neoplasms were isoechoic to thyroid parenchyma. Four (27%) tumors were predominantly isoechoic, containing hypoechoic areas, and 3 (20%) tumors were hyperechoic. Three neoplasms contained cystic components. None of the tumors contained calcifications. One tumor was avascular on Doppler examination. One neoplasm showed only peripheral blood flow. Thirteen tumors showed internal vascularity, 7 of them with peripheral blood flow. Twelve HCNs were benign, and 3 were malignant on pathologic examination. Conclusions. Hürthle cell neoplasms show a spectrum of sonographic appearances from predominantly hypoechoic to hyperechoic lesions and from peripheral blood flow with no internal flow to extensively vascularized lesions. Pathologic criteria differentiating benign and malignant HCNs (absence or presence of a capsular breach, vascular or extrathyroidal tissue invasion, nodal involvement, and distant metastasis) are beyond the resolution of sonography and fine‐needle aspiration biopsy and require removal of the entire lesion. This precludes diagnosis and characterization of HCNs by sonography.

Vascular Complications of Pancreatitis: Imaging and Intervention

The objective of this study was to highlight technical challenges and potential pitfalls of diagnostic imaging, intervention, and postintervention follow-up of vascular complications of pancreatitis. Diagnostic and interventional radiology imaging from patients with pancreatitis from 2002 to 2006 was reviewed. We conclude that biphasic CT is the diagnostic modality of choice. Catheter angiography may (still) be required to diagnose small pseudoaneurysms. Endovascular coiling is the treatment of choice for pseudoaneurysms. Close clinical follow-up is required, as patients may rebleed/develop aneurysms elsewhere.

Utility of MRI Before and After Uterine Fibroid Embolization: Why to Do It and What to Look For

The utility of magnetic resonance imaging (MRI) in the selection, procedure planning, and follow-up of patients undergoing arterial embolization for uterine fibroids is reviewed. Advantages of MRI over ultrasound include multiplanar imaging capability, a larger field of view, increased spatial resolution, improved anatomic detail, and the ability to detect other pelvic disorders. MRI can assess fibroid viability by detecting contrast agent enhancement. Magnetic resonance angiography has a useful role in evaluation of pelvic vasculature. Magnetic resonance parameters such as T1 and T2 relaxation times and diffusion-weighted characteristics have an emerging role in predicting outcome before and after embolization. MRI may be used to evaluate technical success and to image potential complications after embolization.

Image-guided Intervention in Management of Complications of Portal Hypertension: More than TIPS for Success

Management of clinically important sequelae of portal hypertension, such as variceal bleeding and ascites, may involve a combination of medical, endoscopic, surgical, and interventional approaches and procedures. Although clinically significant esophageal and rectal varices are typically visible endoscopically, ectopic varices may require multiplanar portal venous phase computed tomography or magnetic resonance imaging for diagnosis. A detailed understanding of individual vascular anatomy, flow dynamics, and patient-related factors such as cardiac and hepatic status is necessary for appropriate treatment selection in patients with complicated portal hypertension. The hepatic venous pressure gradient is the key indirect measurement of portal venous pressure. Transjugular intrahepatic portosystemic shunt (TIPS) placement is regarded as the archetypal intervention for treating complicated portal hypertension by reducing portal pressure. Various modifications, such as direct portocaval shunt, may be used in patients with challenging vascular anatomy. A subset of patients with obstructed hepatic venous outflow or portal venous inflow should be considered for recanalization. Splenic artery embolization may be considered for reduction of portal pressure in selected patients, particularly when hypersplenism or splenic vein occlusion is a prominent feature. Gastric and ectopic varices may bleed even when the portal pressure is low, and balloon-occluded retrograde transvenous obliteration (BRTO) in such patients may lead to equal or improved outcome compared with TIPS placement. BRTO is not limited by poor hepatic reserve or encephalopathy; however, it does not reduce portal pressure and may aggravate esophageal varices. Interventional radiology plays an important role in maintaining the patency of surgically created portosystemic shunts, and it remains at the forefront of new approaches in shunt design and placement. Supplemental material available at http://radiographics.rsna.org/lookup/suppl/doi:10.1148/rg.335125166/-/DC1.

Repositioning of Covered Stents: The Grip Technique

IntroductionRetrieval and repositioning of a stent deployed beyond its intended target region may be a difficult technical challenge.Materials and MethodsA balloon-mounted snare technique, a variant of the coaxial loop snare technique, is described.ResultsThe technique is described for the repositioning of a covered transjugular intrahepatic portosystemic shunt stent and a covered biliary stent.ConclusionThe balloon-mounted snare technique is a useful technique for retrieval of migrated stents.

Abdominal Manifestations of Systemic Lupus Erythematosus: Spectrum of Imaging Findings

Systemic lupus erythematosus is an immune-mediated syndrome in which the immune response is to non–organ-specific antigens, and virtually every organ in the abdominal cavity may become involved. Only renal involvement forms part of the diagnostic criteria, however, a combination of typically nonspecific findings, including peritoneal surface, enteric, renal, renal tract, pancreatic, adrenal, hepatobiliary, and splenic manifestations, should be looked for in patients with known lupus or other connective tissue disease who are undergoing abdominal imaging and may suggest the diagnosis in patients presenting with an acute abdomen. Our work presents the spectrum of imaging findings of abdominal manifestations of systemic lupus erythematosus.