Comparison of coronary flow reserve estimated by dynamic radionuclide SPECT and multi-detector x-ray CT.

BACKGROUND: Recent technical advances in multi-detector computed tomography (MDCT) allow for assessment of coronary flow reserve (CFR). We compared regional CFR by dynamic SPECT and by dynamic MDCT in patients with suspected or known coronary artery disease (CAD). METHODS: Thirty-five patients, (29 males, mean age 69 years) with greater than average Framingham risk of CAD, underwent dipyridamole vasodilator stress imaging. CFR was estimated using dynamic SPECT and dynamic MDCT imaging in the same patients. Myocardial perfusion findings were correlated with obstructive CAD (≥50% luminal narrowing) on CT coronary angiography (CA). RESULTS: Mean CFR estimated by SPECT and MDCT in 595 myocardial segments was not different (1.51 ± 0.46 vs. 1.50 ± 0.37, p = NS). Correlation of segmental CFR by SPECT and MDCT was fair (r 2 = 0.39, p < 0.001). Bland-Altman analysis revealed that MDCT in comparison to SPECT systematically underestimated CFR in higher CFR ranges. By CTCA, 12 patients had normal CA, 11 had non-obstructive, and 12 had obstructive CAD. CFR by both techniques was significantly higher in territories of normal CA than in territories subtended by non-obstructive or obstructive CAD. SPECT CFR was also significantly different in territories subtended by non-obstructive and obstructive CAD, whereas MDCT CFR was not. CONCLUSION: Despite relative underestimation of high CFR values, MDCT CFR shows promise for assessing the pathophysiological significance of anatomic CAD.

Endovascular treatment with primary stenting of inferior cava vein torsion following orthotopic liver transplantation with modified piggyback technique.

PURPOSE: This study was undertaken to evaluate primary stenting in patients with inferior vena cava torsion after orthotopic liver transplantation performed with modified piggyback technique. MATERIALS AND METHODS: From November 2003 to October 2010, six patients developed clinical, laboratory and imaging findings suggestive of caval stenosis, after a mean period of 21 days from an orthotopic liver transplantation performed with modified piggyback technique. Vena cavography showed stenosis due to torsion of the inferior vena cava at the anastomoses and a significant caval venous pressure gradient. All patients were treated with primary stenting followed by in-stent angioplasty in three cases. RESULTS: In all patients, the stents were successfully positioned at the caval anastomosis and the venous gradient pressure fell from a mean value of 10 to 2 mmHg. Signs and symptoms resolved in all six patients. One patient died 3 months after stent placement due to biliary complications. No evidence of recurrence or complications was noted during the follow-up (mean 49 months). CONCLUSIONS: Primary stenting of inferior vena cava stenosis due to torsion of the anastomoses in patients receiving orthotopic liver transplantation with modified piggyback technique is a safe, effective and durable treatment.

Subclavian artery pseudoaneurysm complicating central venous catheterization: endovascular treatment with Amplatzer Vascular Plug 4 and covered stent.

Central venous catheterization is a routine vascular access procedure; however, it may be associated with life-threatening complications such as arterial puncture, leading to pseudoaneurysm formation. We report a case of a 41-year-old female that developed an iatrogenic left subclavian pseudoaneurysm complicating the attempt of left internal jugular vein cannulation for temporary hemodialysis therapy. The patient underwent urgent endovascular treatment with deployment of covered stent into the left subclavian artery (SCA) after embolization of the origin of the left internal mammary artery with Amplatzer Vascular Plug 4. The patient's recovery was unremarkable. Follow-up till 24 months reveals total exclusion of the pseudoaneurysm of the left SCA with patency of the distal branches.

Endovascular embolization of a third jejunal artery aneurysm: isolation technique using the Amplatzer vascular plug 4.

Aneurysm of the jejunal artery (JA) is very uncommon with few specific symptoms, but can be a lethal entity. When at risk to rupture, it must be treated expeditiously to avoid mortality. We report a case of a 76-year-old male patient that underwent contrast-enhanced multi-detector computed tomography (MDCT) which incidentally reveals a 12 mm saccular aneurysm of the third JA at the bifurcation of the first arcade. Patient underwent successful endovascular embolization using the isolation technique with the Amplatzer Vascular Plug 4. The patient's recovery was unremarkable and he was discharged on postoperative day 5. Follow-up MDCT reveals total exclusion of the saccular aneurysm of the third jejunal artery with patency of the distal branches.

Recurrent acute Budd-Chiari syndrome after right hepatectomy: US color-Doppler vascular pattern and left hepatic vein stenting for treatment.

After extended right hepatectomy remnant liver can be affected by outflow obstruction due to torsion of the inferior vena cava or kinking of the left hepatic vein. Remnant liver fixation is therefore suggested to avoid postoperative acute Budd-Chiari syndrome. Despite remnant liver reposition during surgery, a 76-years-old woman developed complete outflow obstruction. This clinical situation, due to left hepatic vein kinking, was suspected by US examination and confirmed by CT scan that showed a pathological intrahepatic vascular pattern. Patient required urgent relaparotomy and the liver was replaced in normal position. However, recurrence of outflow obstruction occurred and it was ultimately treated by inferior vena cava angiogram with left hepatic vein stenting.

Fiber Bragg Grating Sensor Networks Enhance the In Situ Real-Time Monitoring Capabilities of MLI Thermal Blankets for Space Applications.

The utilization of Fiber Bragg Grating (FBG) sensors in innovative optical sensor networks has displayed remarkable potential in providing precise and dependable thermal measurements in hostile environments on Earth. Multi-Layer Insulation (MLI) blankets serve as critical components of spacecraft and are employed to regulate the temperature of sensitive components by reflecting or absorbing thermal radiation. To enable accurate and continuous monitoring of temperature along the length of the insulative barrier without compromising its flexibility and low weight, FBG sensors can be embedded within the thermal blanket, thereby enabling distributed temperature sensing. This capability can aid in optimizing the thermal regulation of the spacecraft and ensuring the reliable and safe operation of vital components. Furthermore, FBG sensors offer sev eral advantages over traditional temperature sensors, including high sensitivity, immunity to electromagnetic interference, and the ability to operate in harsh environments. These properties make FBG sensors an excellent option for thermal blankets in space applications, where precise temperature regulation is crucial for mission success. Nevertheless, the calibration of temperature sensors in vacuum conditions poses a significant challenge due to the lack of an appropriate calibration reference. Therefore, this paper aimed to investigate innovative solutions for calibrating temperature sensors in vacuum conditions. The proposed solutions have the potential to enhance the accuracy and reliability of temperature measurements in space applications, which can enable engineers to develop more resilient and dependable spacecraft systems.

Nonocclusive mesenteric ischemia in a dialysis patient with extensive vascular calcification.

We describe a case of nonocclusive mesenteric ischemia in a 37-year-old man with hemodialysis-dependent chronic kidney disease due to diabetes who was admitted to our hospital with abdominal pain. A plain radiograph of the abdomen showed distended loops of small bowel and gas in the hepatic portal vein. Multidetector computed tomography showed massive wall calcification of the superior mesenteric artery and its collaterals, pneumatosis intestinalis of a segment of the jejunum, and porto-mesenteric vein gas. Urgent laparotomy confirmed segmental necrosis of the jejunum, which was resected. Pathologic examination showed whole-layer necrosis of the resected bowel without arterial or venous thrombosis. Nonocclusive mesenteric ischemia is an increasingly recognized and potentially lethal complication in hemodialysis patients. In the present case, critical factors for the development of nonocclusive mesenteric ischemia may have included prolonged hypotension during hemodialysis treatments that reduced blood flow to the small bowel and massive vascular calcification that negatively affected compliance of the superior mesenteric artery and its branches.

Final operative and midterm results of the European experience in the RELAY Endovascular Registry for Thoracic Disease (RESTORE) study.

PURPOSE: Thoracic endovascular aortic repair is increasingly becoming the standard treatment of many thoracic aortic pathologies. New reliable and accurate stent grafts are emerging to widen the endovascular treatment options. We report the results of RELAY (Bolton Medical, Barcelona, Spain) in the large RELAY Endovascular Registry for Thoracic Disease (RESTORE) European registry. METHODS: RESTORE is a multicenter, prospective European registry involving 22 centers in seven European countries. The RELAY device is composed of a stent graft (self-expanding nitinol stents and a polyester vascular graft) and a delivery device specifically designed for the thoracic aorta. Included were acute and elective patients presenting with a variety of pathologies (aneurysms, dissections, ulcerations, intramural hematomas, pseudoaneurysms) and lesions in different aortic and anatomic locations (ascending, arch, descending and thoracoabdominal). RESULTS: The registry enrolled 304 patients from April 2005 to January 2009. All-cause mortality at 30 days was 7.2%. Freedom from all cause mortality and freedom from device- and procedure-related mortality at 2 years were 78.5% and 95.9%, respectively. An average of 1.26 graft components were used per patient, with a technical success of 97.7% irrespective of the etiology. Early endoleak rate was 4.6%. Perioperatively, stroke and paraplegia were registered in 1.6% and 2.0%, respectively. CONCLUSIONS: The results of RESTORE support the safety of thoracic endovascular aortic repair with the RELAY stent graft, even in acute and complicated situations. The device was highly efficient in angulated aortic anatomies, with acceptable mortality and a low rate of neurologic complications.

Endovascular treatment of patients with types A and B thoracic aortic dissection using Relay thoracic stent-grafts: results from the RESTORE Patient Registry.

PURPOSE: To evaluate the safety and performance of Relay stent-grafts in patients with acute or chronic aortic dissections. METHODS: Patients with types A or B aortic dissections suitable for treatment with Relay stent-grafts and followed for 2 years after thoracic endovascular aortic repair (TEVAR) were identified from a company-sponsored registry database established in January 2006. Ninety-one consecutive patients (69 men; mean age 65 years) underwent TEVAR with Relay stent-grafts for dissection. Most patients (76, 84%) had type B dissections; 61 of all patients were classified as chronic and 30 as acute. RESULTS: The technical success rate was 95% (97% in acute, 95% in chronic, and 93% in type B dissections). The type I endoleak rate was 7% (7% in acute and 8% in chronic dissections); all occurred in patients with type B dissections. Paraplegia, paraparesis, and stroke occurred in 4, 1, and 2 patients, respectively; 2 cases of paraplegia occurred in patients with acute type B dissections. Thirty-day mortality was 8% (13% in acute and 5% in chronic dissections); all deaths occurred in patients with type B dissections. The 2-year survival rate was 82% in the overall population and 84% in patients with type B dissections. CONCLUSION: The combination of Relay's features, such as stent conformability, radial force, atraumatic design, and controlled deployment and fixation, may contribute to the safety of the Relay stent-grafts for the treatment of thoracic aortic dissections, including acute and chronic type B dissections.

Hepatorenal syndrome: a review.

Hepatorenal Syndrome (HRS) is a serious and life-threatening complication of portal hypertension and end stage liver disease. The cornerstone of treatment is liver transplantation, since renal dysfunction is usually reversible and disappears with the correction of the underlying cause. It is established that HRS has a functional nature and that it is related to renal vasoconstriction. Rapid diagnosis and management are important. Vasoconstrictors together with albumin can ameliorate the effective arterial blood volume and increase renal perfusion pressure. The lack of effective alternative treatment modalities in non responding patients to medical therapy and the almost universally fatal outcome of HRS make transjugular intrahepatic portosystemic stent shunt as a bridge to liver transplantation.

Urachal tumour: case report of a poorly understood carcinoma.

BACKGROUND: Urachal carcinoma is an uncommon neoplasm associated with poor prognosis. CASE PRESENTATION: A 45-year-old man was admitted with complaints of abdominal pain and pollakisuria. A soft mass was palpable under his navel. TC-scan revealed a 11 x 6 cm tumor, which was composed of a cystic lesion arising from the urachus and a solid mass component at the urinary bladder dome. The tumor was removed surgically. Histological examination detected poor-differentiated adenocarcinoma, which had invaded the urinary bladder. The patient has been followed up without recurrence for 6 months. CONCLUSION: The urachus is the embryological remnant of urogenital sinus and allantois. Involution usually happens before birth and urachus is present as a median umbilical ligament. The pathogenesis of urachal tumours is not fully understood. Surgery is the treatment of choice and role of adjuvant treatment is not clearly understood.

Hepatic arterial loop with accessory right hepatic artery aneurysm with celiac atresia: endovascular therapy with a stent and detachable coils.

The present report describes an unusual case of an aneurysm of a right hepatic artery (RHA) branching from the superior mesenteric artery; the accessory RHA was looped to the left hepatic artery arising from the celiac axis (CA) and was associated with congenital atresia of the CA. The accessory RHA aneurysm was treated with the placement of a bare stent and detachable coils through the mesh of the stent. Complete and prompt exclusion of the aneurysm was achieved with blood flow preservation in the parent artery at midterm follow-up.

Radiologic Percutaneous Gastrostomy in Nondistended Stomach: A Modified Approach.

INTRODUCTION: Gastrostomy tube placement for patients requiring long-term nutritional support may be performed using different techniques including endoscopic, surgical, and percutaneous radiologically guided methods. Radiologically inserted gastrostomy (RIG), typically performed when percutaneous endoscopic gastrostomy is not possible, requires proper gastric distension that is achieved by insufflating air through a nasogastric tube. We describe a simple technique to prevent air escape from the stomach during gastrostomy tube placement. To the best of our knowledge, this technique has not yet been described in the literature. MATERIALS AND METHODS: Four patients with unsuccessful percutaneous endoscopic gastrostomy were referred for fluoroscopic-guided gastrostomy. One patient had a pyriform sinus tumor and three had an ischemic stroke causing dysphagia. Gastric distention was not achieved in the patients due to air escaping into the bowel during the standard RIG procedure. A modified approach using a balloon catheter inflated in the pylorus to avoid air passing into the duodenum permitted successful RIG. RESULTS: The modified RIG procedure was successfully carried out in all cases without complications. DISCUSSION: Inadequate air distension of the stomach is an unusual event that causes a failure of gastrostomy tube placement and an increased risk of both major and minor complications. The use of a balloon catheter inflated in the first part of the duodenum prevents the air passage into the bowel allowing the correct positioning of the gastrostomy.

Stress Computed Tomography Myocardial Perfusion Imaging: A New Topic in Cardiology.

Since its introduction about 15 years ago, coronary computed tomography angiography has become today the most accurate clinical instrument for noninvasive assessment of coronary atherosclerosis. Important technical developments have led to a continuous stream of new clinical applications together with a significant reduction in radiation dose exposure. Latest generation computed tomography scanners (≥ 64 slices) allow the possibility of performing static or dynamic perfusion imaging during stress by using coronary vasodilator agents (adenosine, dipyridamole, or regadenoson), combining both functional and anatomical information in the same examination. In this article, the emerging role and state-of-the-art of myocardial computed tomography perfusion imaging are reviewed and are illustrated by clinical cases from our experience with a second-generation dual-source 128-slice scanner (Somatom Definition Flash, Siemens; Erlangen, Germany). Technical aspects, data analysis, diagnostic accuracy, radiation dose and future prospects are reviewed.

Nongated vs electrocardiography-gated CT imaging of blunt aortic root rupture in a trauma patient.

An 18-year-old male, involved in a car accident, underwent a non-gated contrast enhanced CT with apparently no evidence of significant abnormalities of the thoracic aorta. The later onset of aortic valve regurgitation prompted a prospectively ECG-triggered high-pitch spiral acquisition using a dual-source CT system which showed a tear with a huge pseudoaneurysm of the aortic root. The patient underwent successful urgent conservative surgical repair. CT is the primary screening modality for aortic injuries. Cardiac motion artifacts may hamper sensitivity at the root/ascending aorta level when a non ECG-gated technique is used, thus masking a potentially life-threatening condition. ECG-gated-CT should be mandatorily performed in patients with a high suspicion for an aortic root trauma thus allowing timely repair and avoiding a catastrophic event.

Reducing transplant-related mortality after allogeneic hematopoietic stem cell transplantation.

BACKGROUND AND OBJECTIVES: Transplant-related mortality (TRM) following allogeneic hematopoietic stem cell transplantation (HSCT) has been reported to be related to disease stage, duratiion of disease and type of donor. Furthermore, the outcome of transplants performed in the 1990s appears to be better than that of transplants done in the previous decade. The aims of this study were to determine whether these relationships still hold and whether the outcome of transplants is continuing to improve. DESIGN AND METHODS: We analyzed 1180 consecutive patients with leukemia (n=979) or other hematologic malignancies (n=201) undergoing HSCT in 4 time periods: before 1990, 1991-1995, 1996-2000, and 2001-2002. Changes during these eras include increasing patient age, more unrelated transplants, more patients with advanced disease, different graft-versus-host disease (GvHD) prophylaxis, and different management of infections. RESULTS: The actuarial 2-year transplant-related mortality (TRM) differed significantly between the transplant eras (p<0.001) with a significant interaction with disease phase (p=0.018). In patients in first remission (n=585) TRM was 34%, 25%, 21% and 6% in the four transplant eras. The reduction in TRM was less evident in patients in second remission (n=284) (37%, 35%, 30%, 25%) and absent in relapsed patients (n=311) (TRM=45%, 41%, 29%, 51%). This is a consequence of reductions in GvHD, infections and multiorgan failure among patients in remission but not among those who relapse. The actuarial 2-year survival has improved significantly in patients in first remission (54%, 66%, 72%, 78%) but not in those in second remission (38%, 46%, 52%,45%), or relapsed patients (31%, 25%, 36%, 21%). INTERPRETATION AND CONCLUSIONS: In conclusion, TRM has been significantly reduced in first remission patients, suggesting an allograft should be considered in this phase, when appropriate, without delay. There has been no improvement in survival for patients beyond first remission, due to persisting high risk of infections and organ toxicity, a possible consequence of prolonged pre-transplant chemotherapy and neutropenia.

Type-2 hepatorenal syndrome and refractory ascites: role of transjugular intrahepatic portosystemic stent-shunt in eighteen patients with advanced cirrhosis awaiting orthotopic liver transplantation.

BACKGROUND/AIMS: TIPS (transjugular intrahepatic portosystemic stent-shunt) has been used increasingly in the management of refractory variceal bleeding. Its role in the management of refractory ascites and hepatorenal syndrome still awaits further prospective studies. Type-2 hepatorenal syndrome is a moderate steady renal impairment. It arises spontaneously and it is the main mechanism of refractory ascites. Precipitating factors may lead to type-1 hepatorenal syndrome. Hepatorenal syndrome is a common complication of advanced cirrhosis with a 3-month mortality of more than 90% unless treated by orthotopic liver transplantation. However, because of the short survival of patients with hepatorenal syndrome and the limited availability of organs, only a small percentage of patients with hepatorenal syndrome can actually reach orthotopic liver transplantation. That is why awaiting orthotopic liver transplantation we have submitted some suitable patients to a TIPS setting. METHODOLOGY: We have considered eighteen consecutive patients affected by advanced cirrhosis (Child-Pugh 10-12) awaiting orthotopic liver transplantation and suitable for TIPS treatment for the presence of type-2 hepatorenal syndrome (10 males, average age 44.5). The criteria for the diagnosis of hepatorenal syndrome and refractory ascites have been effected according to a consensus recommendation. Organic kidney disease was excluded. After mild intravenous sedation and analgesia a puncture needle was advanced transjugular in a catheter through the inferior cava into one of the three hepatic veins. Subsequently, an intrahepatic branch of the portal vein was punctured and the shunt was established by the implantation of Wallstent (diameter 10 mm; Boston, Scientific, Natick, MA). In all patients, we compared serum creatinine, creatinine-clearance, sodium excretion and urine volume before the intervention and 12 weeks after TIPS. The differences among groups were analyzed using paired Student's t-test. RESULTS: The stent shunt was successfully established in all eighteen patients. Complications occurred in 4 patients (temperature above 38 degrees C or vomiting). No patients have developed hepatic encephalopathy resistant to medical treatment. As for the ascites a complete response with total remission of ascites was obtained in eight patients, while a partial response with the presence of sonographically detectable ascites--without the need of paracentesis--was obtained in ten patients. As regards renal functional parameters we have evidenced a significant improvement after TIPS. CONCLUSIONS: We can notice how the setting of TIPS, at least in the presented case, has allowed the treatment of ascites and, furthermore, has lead to improvement of the renal functional parameters. It all implies the enormous advantage of a better management of the patient waiting for orthotopic liver transplantation and, most of all, the advantage of preparing the patient for the surgical intervention with normal renal functional parameters: in fact, it is well known that the increase of serum creatinine influences the pre- and post-orthotopic liver transplantation course, and in particular can modify the mortality rate of the patient list. The lack of effective alternative treatment modalities and the almost universally fatal outcome of hepatorenal syndrome make TIPS an attractive option in the treatment of hepatorenal syndrome as a bridge to orthotopic liver transplantation.