Follow-up Contrast-enhanced Computed Tomography Scan Research Articles

Tracking Wall Characteristics of Necrotic Pancreatic Fluid Collections in Acute Pancreatitis on Serial Contrast-Enhanced Computed Tomography

Abstract Background Encapsulated pancreatic fluid collection (PFC) is a requisite for endoscopic drainage procedures. The 4-week threshold for defining walled-off necrosis does not capture the dynamic process of encapsulation. We aim to investigate the changes in the wall characteristics of PFC in acute necrotizing pancreatitis (ANP) by comparing baseline contrast-enhanced computed tomography (CECT) with follow-up CT scans. Methods This retrospective study comprised consecutive patients with ANP who underwent a baseline CECT within first 2 weeks and follow-up CECT in the third to fifth weeks of illness. Presence, extent, and encapsulation thickness (defined as enhancing wall around the collection) on baseline CECT were compared with follow-up CT (done in the third–fifth weeks of illness). Results Thirty patients (19 males and 11 females; mean age 41.5 ± 13.5 years) were included in the study. The mean time to first CECT was 10 ± 3.6 days. There were 58 collections. The most common site was the lesser sac (n = 29), followed by the left pararenal space (n = 15). At baseline CT, 52 (89.7%) collections had varying degree of encapsulation (15.3%, complete encapsulation). Complete encapsulation was seen in 52 and 82.6% collections in third and fourth week, respectively. All collections in fifth week and beyond were encapsulated. The wall was thicker on follow-up CECT scans (p < 0.01). The mean wall thickness was not significantly associated with the degree of encapsulation (p = 0.417). There was no significant association between the site and degree of encapsulation (p = 0.546). Conclusion Encapsulation is dynamic and collections may get “walled off” before 4 weeks. Walled-off collections should be defined based on imaging rather than a fixed 4-week revised Atlanta classification threshold.

Acute mesenteric ischemia secondary to superior mesenteric vein thrombosis in a patient with liver cirrhosis: A case report.

Acute mesenteric ischemia due to superior mesenteric vein (SMV) thrombosis is a rare yet potentially life-threatening emergency. Our case report explores this condition in the context of a patient with liver cirrhosis due to Wilson disease. We specifically highlight the complex derangement of the coagulative balance in liver cirrhosis. A 34-year-old female with Wilson disease-related cirrhosis presented with intractable abdominal pain, nausea, and vomiting that showed no response to antispasmodic medication. A contrast-enhanced abdominal computed tomography scan and Doppler ultrasound confirmed an intraluminal filling defect in the SMV, leading to the diagnosis of SMV thrombosis. Prompt anticoagulation, intravenous fluids, and an antibiotic were initiated. Surgical consultation recommended conservative therapy with close monitoring. Over the following 2 days, the patient's condition improved considerably, with almost complete resolution of her symptoms. Genetic testing identified a 4G/4G homozygous genotype of the plasminogen activator inhibitor 1 gene, associated with a higher risk of thrombosis in the vessels of internal organs. After 2 months of sustained anticoagulant therapy, a follow-up contrast-enhanced computed tomography scan revealed near-complete recanalization of the SMV, and the patient remained symptom-free. This case underscores the importance of early detection and treatment of acute mesenteric ischemia in patients with liver cirrhosis, as well as the potential role of genetic factors in thrombosis.

Chronic contained rupture of abdominal aortic aneurism complicated with aortic occlusion: a case report

BackgroundChronic contained rupture is a subtype of an abdominal aortic aneurysm rupture. Its diagnosis is sometimes difficult due to lack of typical symptoms. We would like to report the challenge of diagnosing chronic contained rupture of abdominal aortic aneurysm with a retroperitoneal tumor.Case presentationA 60-year-old man reported perceived lower abdominal pain 7 months earlier that spontaneously remitted. A contrast-enhanced computed tomography (CT) indicated an abdominal aortic aneurysm and a mass lesion surrounding the abdominal aorta and iliac arteries. Fluorine-18-fluorodeoxyglucose positron emission tomography (FDG-PET) showed an increased accumulation of FDG in the margin of the lesion, indicating a retroperitoneal tumor. A CT-guided biopsy revealed only retroperitoneal fibrous tissue with chronic inflammation. We were thus unable to reach a definitive diagnosis. At 1 month after the initial examination, intermittent claudication was newly observed. A follow-up contrast-enhanced CT scan revealed abdominal aortic occlusion. Mass resection and bypass surgery were performed for diagnosis and treatment. Intraoperative and pathological findings led to the diagnosis of chronic contained rupture of an abdominal aortic aneurysm. The patient was discharged 19 days after surgery.ConclusionThe mass peripheral to the abdominal aorta should be considered the possibility not only of tumor but also of chronic contained rupture of an abdominal aortic aneurysm.

Conglomerate Ring-Enhancing Lesions are Common in Solitary Neurocysticercosis and do not always Suggest Neurotuberculosis.

Background and Purpose:Differentiating between neurocysticercosis (NCC) and neurotuberculosis has serious therapeutic implications and this distinction relies heavily on neuroimaging. Few case reports discuss the conglomeration of ring-enhancing lesions (RELs) in patients with solitary NCC. The aim of our study is to describe the imaging findings of conglomerate RELs in a cohort of patients with solitary NCC, emphasizing the frequency of conglomeration.Materials and Methods:This retrospective study included 100 patients with solitary NCC. Two neuroradiologists analyzed contrast-enhanced computed tomography (CT) images regarding morphology, enhancement pattern, location, number of lesions, and degree of perilesional edema. The solitary lesions were classified as solitary discrete RELs (SD-RELs) when a well-defined lesion was seen and solitary conglomerate RELs (SC-RELs) when two or more ring lesions or ring/rings plus disc lesions were present contiguously. Follow-up CT scans were evaluated for the resolution of lesions and surrounding edema.Results:Out of 100 patients, 42 were SD-RELs and 58 were SC-RELs. No statistically significant difference was found between both groups in terms of age of presentation, clinical presentation, lesion size and location, and degree of perilesional edema. Larger lesions (>10 mm) were more likely to show scolex and were associated with greater degree of edema in both subgroups. During follow-up, 13 patients had new lesions (SD-RELs-5, SC-RELs-8). In SD-RELs, follow-up lesions were in the same location in four patients and new location in one; and in SC-RELs, lesions were in the same location in seven and in new location in one case.Conclusion:Conglomeration of RELs is a common finding in patients with solitary NCC.

Transcaval Ureter

Transcaval ureter is a rare condition caused by abnormality in the embryogenesis of the inferior vena cava (IVC). It results from a segmental duplication of the IVC which creates a venous ring that encircles the right ureter. Here, we report a case of a 42-year-old female who presented to us with a history of right flank pain for 2 years. Ultrasonography, intravenous urogram, and contrast-enhanced computed tomography (CECT) scan of the abdomen suggested it to be a retrocaval ureter. On exploration, contrary to the report of imaging, the ureter was found to transverse in between two segments of IVC and thus on table, a diagnosis of the right transcaval ureter as the cause of obstruction was made. The patient underwent segmental ureteral resection followed by ureteroureterostomy. Follow-up CECT scan was done to document two segments of IVC and thus confirm our intraoperative finding.

Anatomical and electrical remodeling with incomplete left atrial appendage ligation: Results from the LAALA-AF registry.

The anatomical, electrical, and clinical impact of incomplete Lariat left atrial appendage ligation remains unclear. We studied LAA anatomy pre- and postligation using contrast enhanced-computed tomography (CT) scans in 91 patients with atrial fibrillation (AF) who subsequently underwent catheter ablation (CA). Eleven patients had an incomplete exclusion (12%) with a central leak ranging from 1 to 5 mm. Despite incomplete ligation; the LAA volume were reduced by 67% postprocedurally when compared to preprocedure. In 7 patients with a leak between 1 and 3 mm, there was a 77% reduction in LAA volume beyond the ligation site suggestive of remodeling of the LAA. In 4 patients with larger (4-5 mm) leak the LAA remnants (LAARs) were slightly larger than those with smaller leaks on follow-up CT scan. Three out of the 4 demonstrated LAA electrical activity during CA and underwent isolation of the LAA ostium. Follow-up imaging showed two of these LAARs completely sealed with no communication with the left atrium. There was no significant difference in the AF recurrence rates between the patients who had a leak versus those with complete ligation (4 of 11 [36%] vs. 22 of 80 [27%]; P=0.6). Oral anticoagulation was discontinued in all patients with small leaks and 2 patients with large leaks that sealed completely upon follow-up imaging. There were no strokes or TIAs at 12 months. Despite incomplete LAA ligation by Lariat device there is significant anatomical and electrical remodeling that resulted in reduction in LAA size, volume, and electrical activity.

Delayed splenic vascular injury after nonoperative management of blunt splenic trauma

BackgroundDelayed splenic vascular injury (DSVI) is traditionally considered a rare, often clinically occult, harbinger of splenic rupture in patients with splenic trauma that are managed conservatively. The purpose of our study was to assess the incidence of DSVI and associated features in patients admitted with blunt splenic trauma and managed nonoperatively. Materials and methodsA retrospective analysis was conducted over a 4-y time. Patients admitted with blunt splenic trauma, managed no-operatively and with a follow-up contrast-enhanced computed tomography (CT) scan study during admission were included. The CT scans were reviewed for American Association for the Surgery of Trauma splenic injury score, amount of hemoperitoneum, and presence of DSVI. Logistic regression models were used to investigate the risk factors associated with DSVI. ResultsA total of 100 patients (60 men and 40 women) constituted the study group. Follow-up CT scan demonstrated a 23% incidence of DSVI. Splenic artery angiography validated DSVI in 15% of the total patient population. Most DSVIs were detected only on arterial phase CT scan imaging. The American Association for the Surgery of Trauma splenic injury score (odds ratio = 1.73; P = 0.045) and the amount of hemoperitoneum (odds ratio = 1.90; P = 0.023) on admission CT scan were associated with the development of DSVI on follow-up CT scan. ConclusionsDSVI on follow-up CT scan imaging of patients managed nonoperatively after splenic injury is common and associated with splenic injury score assessed on admission CT scan.

The Impact of Transient Hepatic Attenuation Differences in the Diagnosis of Pseudoaneurysm and Arteriovenous Fistula on Follow-Up CT Scans after Blunt Liver Trauma.

A feared complication to liver trauma is delayed vascular complication, such as pseudoaneurysm and arteriovenous fistula (PS/AF) seen as focal enhancement on contrast-enhanced computed tomography (CT) in the arterial phase. A hyperdense area termed transient hepatic attenuation difference (THAD) representing altered hepatic blood flow can be seen in the arterial phase near the liver lesion. The objective of this study was to describe THAD and PS/AF on follow-up CT after blunt liver trauma, and to evaluate if THAD influenced the evaluation of PS/AF. Three radiology residents retrospectively evaluated scans of 78 patients. The gold standard for PS/AF was an evaluation by an experienced senior radiologist, while THAD was a consensus between the residents. PS/AF was present in 14% and THAD in 54%. THAD was located in the periphery of the lesion with hazy borders and mean HU levels of 100, while PS/AF was located within the lesion with focal enhancement and mean HU levels of 170 (p < 0.05). In evaluation of PS/AF, the likelihood of agreement between the observers and the gold standard was 89% when THAD was present, and 98% when THAD was absent (p = 0.04). THAD is common and can hamper the evaluation of PS/AF.

Solitary pulmonary nodule: A rare presentation of pulmonary mucormycosis in an immunocompetent adult

Pulmonary mucormycosis is a rare opportunistic infection of immunocompromised individuals. Here, we report a case of 70-year-old male, smoker presenting with high-grade fever for 2 weeks and episodes of hemoptysis. Contrast-enhanced computed tomography (CT) thorax revealed a solitary pulmonary nodule measuring 2.3 × 1.6 cm in the right upper lobe. CT guided fine needle aspiration cytology and true cut biopsy showed plenty of typical fungal hyphae consistent with the diagnosis of mucormycosis. Fungal culture confirmed the organism as mucor. Positron emission tomography-CT scan showed a non- 18 fluorodeoxy glucose avid nodule ruling out possibility of malignancy. Investigation did not reveal any evidence of immunosuppression. Patient was treated with intravenous liposomal amphotericin B for 4 weeks. Follow-up chest X-ray and CT scan after 6 weeks were normal.

Comparison of attachment site endoleak rates in Dacron versus native aorta landing zones after thoracic endovascular aortic repair

Type I attachment site endoleaks are the most common cause for reintervention after thoracic endovascular aortic repair (TEVAR) and represent treatment failures. Deployment of endografts in segments of the aorta previously replaced with Dacron grafts may be associated with reduced type I endoleak due to mechanical stability and decreased potential for aortic remodeling. However, no study has rigorously examined endoleak rates in Dacron landing zones vs native aorta. A retrospective analysis of a prospectively maintained database was performed to identify all patients undergoing TEVAR at a single referral institution between May 2002 and June 2012. Overall, 319 patients undergoing 345 procedures had at least one follow-up contrast-enhanced computed tomography scan to assess for postoperative type I endoleak. Attachment site landing zones were classified as native aorta, Dacron, or endograft if landed in a previously placed endograft. Patient characteristics and type I endoleak rates were compared among the three groups. Identified were 697 proximal or distal landing zones (native aorta, 599; Dacron, 79; and endograft, 19). Patients with at least one Dacron landing zone had higher rates of hypertension (P < .01), chronic obstructive pulmonary disease (P = .04), and prior aortic surgery (P < .01) and were more likely to have undergone complex hybrid repairs (P < .01). Cumulative type I endoleak rates were equivalent between the three types of landing zone (native aorta, 3.7%; Dacron, 2.5%; endograft, 0%; P = .44). Two type I endoleaks occurred with Dacron landing zones in the first tertile of TEVAR experience and with Dacron landing zone lengths of <2.5 cm. Evaluation of endoleak rates by tertile of experience demonstrated decreased type I endoleak rates in Dacron landing zones between the first and second/third tertiles of experience (13.3% vs 0%, P = .03) after a policy of using >4 to 5 cm (twice the device instructions for use) of Dacron overlap was initiated. Endograft deployment within long-segment (landing zone length of >4-5 cm) Dacron represents a durable option for aortic repair and was associated with a 0% rate of type I endoleak. In cases of a borderline native aortic landing zone, a hybrid procedure to create an adequate Dacron landing zone may be warranted to decrease the risk of type I endoleak and treatment failure.

1297 FLUORODEOXYGLUCOSE POSITRON EMISSION TOMOGRAPHY/COMPUTED TOMOGRAPHY FOR PREOPERATIVE STAGING AND POSTOPERATIVE FOLLOW-UP OF UROTHELIAL CARCINOMA

You have accessJournal of UrologyBladder Cancer: Detection & Screening1 Apr 20131297 FLUORODEOXYGLUCOSE POSITRON EMISSION TOMOGRAPHY/COMPUTED TOMOGRAPHY FOR PREOPERATIVE STAGING AND POSTOPERATIVE FOLLOW-UP OF UROTHELIAL CARCINOMA Anwar Alesawi, Andre Caron, Alain Bergeron, Helene Hovington, Vincent Fradet, Louis Lacombe, and Yves Fradet Anwar AlesawiAnwar Alesawi Quebec, Canada More articles by this author , Andre CaronAndre Caron Quebec, Canada More articles by this author , Alain BergeronAlain Bergeron Quebec, Canada More articles by this author , Helene HovingtonHelene Hovington Quebec, Canada More articles by this author , Vincent FradetVincent Fradet Quebec, Canada More articles by this author , Louis LacombeLouis Lacombe Quebec, Canada More articles by this author , and Yves FradetYves Fradet Quebec, Canada More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2013.02.2651AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES The treatment and prognosis of bladder cancer depends on lymph node involvement in addition to other factors, but the accuracy of conventional imaging modalities for the prediction of nodal involvement or even detection of recurrence in early stage is limited. This study retrospectively investigated the value of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) in the staging and follow up of urothelial carcinoma in comparison to contrast-enhanced computed tomography (CT). METHODS We reviewed 148 files of urothelial carcinoma patients. Of these, 134 had initial and 80 had follow-up PET/CT scans while 103 patients had initial and 82 had follow-up CT scans. Initial CT and PET/CT results were correlated with histopathology data (grade, stage and lymph node status). Follow-up CT and PET/CT results were confirmed by repeated imaging studies. RESULTS The sensitivity for detecting lymph node metastasis before surgery was 43.39% vs 43.58% while the specificity was 100% vs 95.23% for PET/CT scan vs CT scan, respectively. PET/CT scan had higher specificity in detecting recurrence (97.87% vs 90.19%) with higher positive predictive value (96.97% vs 85.7%). There was a significant association between recurrence discovered by PET/CT scan and the nodal status as 86.7% of patients who developed recurrence had positive lymph node whereas 13.3% had negative lymph node at surgery (p<0.0001, chi square). In addition, stage status at surgery was significantly associated with PET/CT scan discovered recurrence as 86.7% of patients who developed recurrence were ≥pT3 while 13.3% were ≤pT2 (p<0.005, chi square). CONCLUSIONS PET/CT scan is not inferior to CT scan in detecting positive lymph nodes before surgery of urothelial cancers while it is superior to CT scan in detecting recurrence after surgery. © 2013 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 189Issue 4SApril 2013Page: e530 Advertisement Copyright & Permissions© 2013 by American Urological Association Education and Research, Inc.MetricsAuthor Information Anwar Alesawi Quebec, Canada More articles by this author Andre Caron Quebec, Canada More articles by this author Alain Bergeron Quebec, Canada More articles by this author Helene Hovington Quebec, Canada More articles by this author Vincent Fradet Quebec, Canada More articles by this author Louis Lacombe Quebec, Canada More articles by this author Yves Fradet Quebec, Canada More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Transradial approach for transcatheter selective superior mesenteric artery urokinase infusion therapy in patients with acute extensive portal and superior mesenteric vein thrombosis

To evaluate the feasibility and efficacy of urokinase infusion therapy via a transradial approach for transcatheter superior mesenteric artery (SMA) in patients with acute extensive portal and superior mesenteric venous thrombosis. During a period of 8 years, 47 patients with acute extensive thrombosis of portal vein (PV) and superior mesenteric veins (SMV) received urokinase infusion therapy by transcatheter selective SMA via radial artery. Their mean age was 44 ± 13 years (range: 19 - 65). Through radial sheath, a 5F catheter was placed into SMA and subsequently the infusion of urokinase was given for 5 - 11 days (mean: 7.1 ± 2.5). Adequate anticoagulation was initiated during treatment, throughout hospitalization and post-discharge. Follow-up contrast-enhanced computed tomography (CT) was performed in each patient every 3 days and before the removal of infusion catheter. Termination of urokinase infusion therapy was decided on the basis of clinical and radiographic findings. Technical success was achieved in all patients. Two patients had worsening abdominal pain, developed the signs of peritonitis at 24 hours after interventional treatment and underwent eventual laparotomy with the resection of necrotic bowel. Substantial clinical improvement was observed in 45 (95.7%) of them after the procedure. Minor complications at the radial puncture site were observed in 7 patients (14.9%) and infusion therapy continued. Follow-up CT scans at pre-discharge demonstrated a nearly complete disappearance of PV-SMV thrombosis in 29 patients (64.4%) and partial recanalization of PV-SMV thrombosis in 16 patients (35.6%). They were discharged at 9 - 20 days (mean: 12 ± 6) post-admission. The mean post-discharge duration of follow-up was 48 ± 20 months. Recurrent episodes of PV and SMV thrombosis were observed in 2 (4.4%) patients at 6 months and 5 years respectively post-discharge and they were treated successfully with urokinase infusion. The transcatheter SMA urokinase infusion therapy via a transradial approach for plus anticoagulation is both safe and effective for the management of patients with acute extensive PV-SMV thrombosis.

Endovascular treatment of thoracic aorta injury after spinal column surgery

A 61-year-old woman with a history of left dorso-lumbar scoliosis and severe dorso-lumbar kyphosis underwent surgical treatment of a spinal deformity. Surgery was conducted on the patient by performing a dorso-lumbar spinal arthrodesis (T6-L5) by means of the insertion of two longitudinal rods and a number of pedicle-expander screws at different vertebral levels. Following the orthopedic surgery, the patient presented paraparesis of the lower limbs and anemia that required transfusion. In the immediate postoperative period, a noncontrast-enhanced computed tomography (CT) scan was obtained to assess the medullary canal. A deviation of the left screw placed at T6 was detected; this screw projected outward from the vertebral cortex, protruding into the descending thoracic aorta. A contrast-enhanced CT scan showed that the screw had been malpositioned, and the image was highly suggestive of a perforation of the aortic wall, despite a lack of evidence of a peri-aortic hematoma, extravasation of contrast medium, or pleural effusion. The patient remained hemodynamically stable, and the decision was to perform an endovascular repair electively within 24 hours (A, Cover). In the operating room, a transesophageal echocardiogram (TEE) showed a metal object in the uppermost portion of the descending aorta constricting the arterial wall and giving rise to a tent-shaped image. A turbulent flow beneath the arterial intima and an intramural hematoma without active bleeding were found at that level (B). The patient was placed in a right decubitus position in the operating room to simultaneously perform the endovascular surgery of the thoracic aorta and the removal of the screw by the orthopedic surgeon. A single 2828100-mm Medtronic Valiant (Medtronic, Santa Rosa, Calif) thoracic endoprosthesis was introduced through the left common femoral artery into the proximal descending thoracic aorta at the site of injury. Afterward, an orthopedic surgeon manually removed the screw placed at D6, and the endograft was then expanded with a Reliant Stent Graft Balloon Catheter (Medtronic). There was no evidence of any leakage or signs of bleeding by TEE and intraoperative angiographic control. During the postoperative period, the patient recovered lower limb strength and mobility, and she was discharged uneventfully within 72 hours. A follow-up contrastenhanced CT scan that did not show signs of complications was obtained 1 month after the repair (C).

Primary mediastinal Hodgkin lymphoma and rebound thymic hyperplasia: differentiation with chemical-shift magnetic resonance imaging after treatment

A 30-year-old man complained of progressive fatigue, cough and mild intermittent fever of 3 months duration. Chest radiography showed a smoothly marginated mediastinal mass. Contrast-enhanced computed tomography (CT) scan depicted a slightly heterogeneous anterior mediastinal solid lesion with smooth margins (Fig. 1). Chemical-shift magnetic resonance (CSMR) imaging demonstrated no apparent decrease in signal intensity of the lesion on transverse T1-weighted opposed-phase images (Fig. 2b) relative to in-phase images (Fig. 2a), suggesting the absence of fat tissue component within the mass. Chemical-shift ratio (CSR), determined by comparing the signal intensity of the mass with that of the paraspinal muscle on both in-phase and opposed-phase images, was 1.035. CT and fluorodeoxyglucose positron emission tomography (FDG-PET) did not show any other apparent site of disease. CT-guided transthoracic needle core-biopsy demonstrated Hodgkin disease. The patient was treated with combined-modality therapy and underwent complete remission. Six months after the end of treatments, follow-up CT scan depicted a homogeneous soft-tissue structure with a biconvex margin in the anterior mediastinum (Fig. 3), characterized by positive attenuation values without evidence of fatty component. To differentiate hyperattenuating rebound thymic hyperplasia from recurrence of lymphoma, patient underwent CSMR. CSMR demonstrated high decrease in signal intensity of the mass on opposed-phase (Fig. 4b) relative to in-phase images (Fig. 4a), suggesting the presence of fat within tissue, and therefore the diagnosis of hyperplastic thymus. CSR was 0.585. No increase in size of the anterior mediastinal tissue was detected at follow-up CT performed at 6, 12 and 18 months. Meanwhile, patient did not undergo any treatment because neither clinical nor biochemical signs of relapse were found in this period. At present, he remains in complete remission, with a follow-up of 20 months. CSMR imaging is more sensitive than other fat-suppressed MR sequences for detecting microscopic fat within tissue. CSMR demonstrates the presence of an intravoxel mixture of fat and water in tissue, which would be indistinct at CT, by showing homogeneously decreased signal intensity on the opposed-phase images relative to the inphase images, with CSR value less than 0.7. In clinical

Outcome of renal stenting for renal artery coverage during endovascular aortic aneurysm repair

This study was conducted to determine the outcome of adjunctive renal artery stenting for renal artery coverage at the time of endovascular abdominal aortic aneurysm repair (EVAR). Between August 2000 and August 2008, 29 patients underwent elective EVAR using bifurcated Zenith stent grafts (Cook, Indianapolis, Ind) and simultaneous renal artery stenting. Renal artery stenting during EVAR was performed with endograft "encroachment" on the renal artery ostium (n = 23) or placement of a renal stent parallel to the main body of the endograft ("snorkel," n = 8). Follow-up included routine contrast-enhanced computed tomography (CT), multiview abdominal radiographs, and serum creatinine measurement at 1, 6, and 12 months, and then yearly thereafter. Thirty-one renal arteries were stented successfully in 29 patients. The 18 patients with planned renal artery stent placement had a proximal neck length <15 mm. Mean proximal neck length was shorter in patients who underwent the "snorkel" technique (6.9 +/- 3.1 mm) compared with those with planned endograft encroachment (9.9 +/- 2.6 mm). None of the patients with unplanned endograft encroachment had neck lengths <15 mm (mean length, 26.3 +/- 10.2 mm). Mean proximal neck angulation was 42.8 degrees +/- 24.0 degrees and did not differ between the groups. One patient had a type I endoleak on completion angiography, and two additional patients had a type I endoleak on the first postoperative CT scan. All type I endoleaks resolved by the 1-month postoperative CT scan. The primary assisted patency of renal artery stents was 100% at a median follow-up of 12.5 months (range, 2 days-77.4 months). In one patient near occlusion of a renal artery stent was noted on follow-up CT scan at 9 months; patency was restored by placement of an additional stent. One patient required dialysis after sustained hypotension from a right external iliac artery injury that resulted in prolonged postoperative bleeding. Mean serum creatinine was 1.1 +/- 0.3 mg/dL at baseline, 1.2 +/- 0.5 mg/dL at 1 month of follow-up, and 1.2 +/- 0.5 mg/dL at 2 years of follow-up. There were no late type I endoleaks (>1 month postoperatively) or stent graft migrations. Adjunctive renal artery stenting during endovascular AAA repair using the "encroachment" and "snorkel" techniques is safe and effective. Short- and medium-term primary patency rates are excellent, but careful follow-up is needed to determine the durability of these techniques.

Successful treatment of cerebral tuberculosis in a liver transplant recipient

A 62-year-old male of Pakistani origin, who had undergone orthotopic liver transplantation (OLT) for hepatitis C cirrhosis 4 years previously, presented with increasing confusion, lethargy, and vomiting of 4 days' duration. There were no specific localizing neurological signs. There was no history of fever, weight loss, or respiratory problems. He did not give any history of having contracted tuberculosis (TB), although his sister had been treated for pulmonary TB 5 years previously. The patient had been resident in the United Kingdom for more than 30 years and traveled to Pakistan every 2 to 3 years but had not made any trips after his transplant. A pretransplant chest X-ray had not revealed any evidence of TB, and a Mantoux test had been negative. He had received 300 mg of isoniazid (INH) daily for 6 months post-OLT for latent TB infection according to the unit protocol for high-risk patients. His posttransplant course had been largely uneventful with no episodes of acute rejection, and cyclosporine and azathioprine immunosuppression was maintained. CT, computed tomography; INH, isoniazid; OLT, orthotopic liver transplantation; TB, tuberculosis. A contrast-enhanced computed tomography (CT) scan of the brain showed discrete ring-enhancing lesions in the right occipital lobe and the cerebellum with surrounding vasogenic edema and a mass effect (Fig. 1). There were additional pulmonary lesions on a chest CT scan. A stereotactic brain biopsy revealed a liquefied purulent material, from which Mycobacterium tuberculosis grew in a culture. The patient was started on triple-drug antitubercular therapy with INH, rifampicin, and pyrazinamide with pyridoxine for 9 months, following which his neurological status improved. His graft function remained stable throughout his treatment course, but he required multiple readmissions for social reasons. A repeat CT scan 3 years after his craniotomy showed complete resolution of the lesion (Fig. 2). He made a complete recovery and remains well 40 months after the completion of treatment. Ring-enhancing lesion in the occipital lobe with surrounding edema. Three-year follow-up CT scan showing complete resolution of the lesion. The incidence of TB after organ transplantation varies from 0.8% to up to 15% in developing countries.1, 2 The diagnosis of posttransplant TB infection can be challenging, and patients may not present with classical clinical features. Disseminated and extrapulmonary disease is common among solid-organ transplant recipients, although intracranial TB infection is uncommon.3, 4 Risk factors for the development of posttransplant TB include diabetes, chronic liver disease, and a history of TB.5 INH prophylaxis is used for high-risk populations in most transplant units, with debatable benefit and the risks of hepatotoxicity and development of drug-resistant strains.3, 6, 7 A recent randomized control trial for INH prophylaxis in renal transplant recipients revealed a nonsignificant trend toward protection from active disease post-prophylaxis.8 Immigrants from areas of high TB incidence, such as the Indian subcontinent, may benefit from a treatment for latent TB infection, which may range from 6 to 9 months. This patient had received a 6-month course of INH prophylaxis after OLT, which is standard in this unit. Although it is possible that this patient acquired a new infection after the INH treatment because of re-exposure, antitubercular therapy may delay the emergence of active infection.9 In rare cases, TB infection can also be acquired from the donor.10 An intracerebral malignancy such as lymphoma or intracerebral metastases as well as abscesses can present with ring-enhancing lesions on a contrast-enhanced CT scan and should be considered in the differential diagnosis. The final diagnosis is based on a histological examination of tissue or the growth of M. tuberculosis in a culture. Antitubercular therapy in solid-organ transplant recipients poses special problems because of drug interactions with immunosuppressive regimens, which can precipitate rejection.11 INH, rifampicin, and pyrazinamide can cause significant derangement of liver function, and close liver monitoring is necessary during treatment. Alternative treatment regimens using rifabutin have been described with acceptable results and good graft survival.12 In summary, intracranial tubercular infection following OLT is extremely rare but should be considered in the differential diagnosis of a ring lesion on a head CT scan, especially in ethnic groups with a high background incidence of TB. To our knowledge, this is only the second such case after OLT reported in the literature.4 In contrast to the previously reported patient, this patient made a complete recovery following 9 months of antitubercular therapy.

Small hepatocellular carcinoma: MR follow-up of treatment with percutaneous ethanol injection.

To assess the potential role of magnetic resonance (MR) imaging in the follow-up evaluation of small hepatocellular carcinoma (HCC) treated with percutaneous ethanol injection (PEI), 31 patients with a single HCC lesion less than 3.0 cm in diameter underwent MR imaging at 0.5 T before and after treatment. Posttreatment follow-up included contrast material-enhanced computed tomography (CT) and fine-needle biopsy in all cases. The most important characteristic of the treated HCC lesions was hypointensity on T2-weighted MR images in cases (27 of 31) in which complete tumor necrosis was achieved with PEI. This feature corresponded to a nonenhanced, low-attenuation area on follow-up contrast-enhanced CT scans. Four HCCs were positive for malignant cells at 6-month fine-needle biopsy; in these lesions, residual tumor tissue was of high signal intensity on T2-weighted MR images and of high attenuation on contrast-enhanced CT scans. In each case, incomplete tumor necrosis was confirmed at pathologic examination of the surgical specimen.