Farah G. Irani

Quality Assurance Guidelines for Percutaneous Vertebroplasty

Vertebral compression fracture is the reduction in individual vertebral body height by 20% or 4 mm [7]. PVP is a therapeutic, image-guided procedure that involves injection of radio-opaque cement into a partially collapsed vertebral body, in an effort to relieve pain and provide stability.

Post-radioembolization yttrium-90 PET/CT - part 2: dose-response and tumor predictive dosimetry for resin microspheres

BackgroundCoincidence imaging of low-abundance yttrium-90 (90Y) internal pair production by positron emission tomography with integrated computed tomography (PET/CT) achieves high-resolution imaging of post-radioembolization microsphere biodistribution. Part 2 analyzes tumor and non-target tissue dose-response by 90Y PET quantification and evaluates the accuracy of tumor 99mTc macroaggregated albumin (MAA) single-photon emission computed tomography with integrated CT (SPECT/CT) predictive dosimetry.MethodsRetrospective dose quantification of 90Y resin microspheres was performed on the same 23-patient data set in part 1. Phantom studies were performed to assure quantitative accuracy of our time-of-flight lutetium-yttrium-oxyorthosilicate system. Dose-responses were analyzed using 90Y dose-volume histograms (DVHs) by PET voxel dosimetry or mean absorbed doses by Medical Internal Radiation Dose macrodosimetry, correlated to follow-up imaging or clinical findings. Intended tumor mean doses by predictive dosimetry were compared to doses by 90Y PET.ResultsPhantom studies demonstrated near-perfect detector linearity and high tumor quantitative accuracy. For hepatocellular carcinomas, complete responses were generally achieved at D70 > 100 Gy (D70, minimum dose to 70% tumor volume), whereas incomplete responses were generally at D70 < 100 Gy; smaller tumors (<80 cm3) achieved D70 > 100 Gy more easily than larger tumors. There was complete response in a cholangiocarcinoma at D70 90 Gy and partial response in an adrenal gastrointestinal stromal tumor metastasis at D70 53 Gy. In two patients, a mean dose of 18 Gy to the stomach was asymptomatic, 49 Gy caused gastritis, 65 Gy caused ulceration, and 53 Gy caused duodenitis. In one patient, a bilateral kidney mean dose of 9 Gy (V20 8%) did not cause clinically relevant nephrotoxicity. Under near-ideal dosimetric conditions, there was excellent correlation between intended tumor mean doses by predictive dosimetry and those by 90Y PET, with a low median relative error of +3.8% (95% confidence interval, -1.2% to +13.2%).ConclusionsTumor and non-target tissue absorbed dose quantification by 90Y PET is accurate and yields radiobiologically meaningful dose-response information to guide adjuvant or mitigative action. Tumor 99mTc MAA SPECT/CT predictive dosimetry is feasible. 90Y DVHs may guide future techniques in predictive dosimetry.

Randomized clinical trial of cutting balloon angioplasty versus high-pressure balloon angioplasty in hemodialysis arteriovenous fistula stenoses resistant to conventional balloon angioplasty.

PURPOSE To compare the efficacy and safety of cutting balloon angioplasty (CBA) versus high-pressure balloon angioplasty (HPBA) for the treatment of hemodialysis autogenous fistula stenoses resistant to conventional percutaneous transluminal angioplasty (PTA). MATERIALS AND METHODS In a prospective, randomized clinical trial involving patients with dysfunctional, stenotic hemodialysis arteriovenous fistulas (AVFs), patients were randomized to receive CBA or HPBA if conventional PTA had suboptimal results (ie, residual stenosis > 30%). A total of 516 patients consented to participate in the study from October 2008 to September 2011, 85% of whom (n = 439) had technically successful conventional PTA. The remaining 71 patients (mean age, 60 y; 49 men) with suboptimal PTA results were eventually randomized: 36 to the CBA arm and 35 to the HPBA arm. Primary and secondary target lesion patencies were determined by Kaplan-Meier analysis. RESULTS Clinical success rates were 100% in both arms. Primary target lesion patency rates at 6 months were 66.4% and 39.9% for CBA and HPBA, respectively (P = .01). Secondary target lesion patency rates at 6 months were 96.5% for CBA and 80.0% for HPBA (P = .03). There was a single major complication of venous perforation following CBA. The 30-day mortality rate was 1.4%, with one non-procedure-related death in the HPBA group. CONCLUSIONS Primary and secondary target lesion patency rates of CBA were statistically superior to those of HPBA following suboptimal conventional PTA. For AVF stenoses resistant to conventional PTA, CBA may be a better second-line treatment given its superior patency rates.

Post-radioembolization yttrium-90 PET/CT - part 1: diagnostic reporting

BackgroundYttrium-90 (90Y) positron emission tomography with integrated computed tomography (PET/CT) represents a technological leap from 90Y bremsstrahlung single-photon emission computed tomography with integrated computed tomography (SPECT/CT) by coincidence imaging of low abundance internal pair production. Encouraged by favorable early experiences, we implemented post-radioembolization 90Y PET/CT as an adjunct to 90Y bremsstrahlung SPECT/CT in diagnostic reporting.MethodsThis is a retrospective review of all paired 90Y PET/CT and 90Y bremsstrahlung SPECT/CT scans over a 1-year period. We compared image resolution, ability to confirm technical success, detection of non-target activity, and providing conclusive information about 90Y activity within targeted tumor vascular thrombosis. 90Y resin microspheres were used. 90Y PET/CT was performed on a conventional time-of-flight lutetium-yttrium-oxyorthosilicate scanner with minor modifications to acquisition and reconstruction parameters. Specific findings on 90Y PET/CT were corroborated by 90Y bremsstrahlung SPECT/CT, 99mTc macroaggregated albumin SPECT/CT, follow-up diagnostic imaging or review of clinical records.ResultsDiagnostic reporting recommendations were developed from our collective experience across 44 paired scans. Emphasis on the continuity of care improved overall diagnostic accuracy and reporting confidence of the operator. With proper technique, the presence of background noise did not pose a problem for diagnostic reporting. A counter-intuitive but effective technique of detecting non-target activity is proposed, based on the pattern of activity and its relation to underlying anatomy, instead of its visual intensity. In a sub-analysis of 23 patients with a median follow-up of 5.4 months, 90Y PET/CT consistently outperformed 90Y bremsstrahlung SPECT/CT in all aspects of qualitative analysis, including assessment for non-target activity and tumor vascular thrombosis. Parts of viscera closely adjacent to the liver remain challenging for non-target activity detection, compounded by a tendency for mis-registration.ConclusionsAdherence to proper diagnostic reporting technique and emphasis on continuity of care are vital to the clinical utility of post-radioembolization 90Y PET/CT. 90Y PET/CT is superior to 90Y bremsstrahlung SPECT/CT for the assessment of target and non-target activity.

Quality Assurance Guidelines for Placement of Gastroduodenal Stents

Gastroduodenal obstruction is often a preterminal event in advanced upper gastrointestinal malignant disease. Patients with gastric outlet and duodenal obstruction often exhibit intractable nausea and vomiting, inability to eat and ‘‘food fear.’’ The consequences are gastric distension, weight loss, anorexia, dehydration and electrolyte imbalance, leading to a markedly impaired quality of life [1–6]. Furthermore, these patients are at constant risk of aspiration and pneumonia [3, 6]. In view of their advanced disease, curative surgery is not possible and without some form of palliative intervention to maintain enteral nutrition these patients die in hospital. In the past, surgical gastroenterostomy, either at a laparotomy or via laparoscopy, with a technical success rate of 90% was the only therapeutic option [7, 8]. However, the invasiveness of this procedure, compounded by the poor general condition of these patients resulted in a complication rate of 25–35% [7, 9–11] and a perioperative mortality rate of 2% [9, 10]. Surgery is associated with prolonged stay in hospital [10, 12–15] and significant cost [10, 13–15]. Poor function of the gastroenterostomy with persistent nausea and vomiting occurs in up to 90% of cases [10, 13, 15, 16]. Percutaneous jejunostomy or gastrojejunostomy may be employed but the long-term results are poor. The catheters sometimes become occluded or dislocated [17–19], are a source of infection, serve to constantly remind patients of their illness [18, 19], do not allow oral intake of solids [20, 21], and carry a risk of aspiration [6, 18, 19]. Nasogastric tubes provide gastric decompression but cannot be used for enteral feeding. Two-valve nasojejunal tubes enable both gastric decompression and enteral feeding but long-term placement is very uncomfortable and does not improve the patient s quality of life [6]. Radiological insertion of large-diameter, self-expanding stents can overcome gastroduodenal obstruction and re-establish oral feeding in patients who are in poor general condition. With refinement of the technique and the development of enteral stents, this procedure is becoming the method of choice in the palliation of gastric outlet and duodenal obstruction in patients with advanced upper gastrointestinal malignant disease.

Endovenous Laser Therapy in the Treatment of Lower-limb Venous Ulcers

PURPOSE To assess the efficacy of endovenous laser therapy (EVLT) in the treatment of lower-limb venous ulcers secondary to venous reflux. MATERIALS AND METHODS Forty-four of 139 patients referred for EVLT from January 2004 to August 2007 had nonhealing venous ulcers. Preprocedural duplex ultrasound (US) was performed to document saphenous venous reflux secondary to saphenofemoral/saphenopopliteal junction incompetence, deep venous insufficiency, and deep vein thrombosis. Follow-up intervals were within 1 week, monthly until ulcer healing, and every 6 months thereafter. Mean follow-up period was 35.8 months (range, 8.1-59.3 months). RESULTS Mean great saphenous vein (GSV) diameter and length treated were 9.9 mm (range, 5.5-16.0 mm) and 36.7 cm (range, 20.0-60.0 cm). Mean laser energy used was 3,292 J (range, 1,392-4,971 J). Mean energy deposited per centimeter of vein was 93.6 J/cm (range, 45.2-182.0 J/cm). Mean laser time was 232 seconds (range, 99-347 sec). Fifteen patients with follow-up duplex US had no GSV flow at 6 months, with nonvisualization indicating complete obliteration. Ulcer healing occurred as early as 1 week after the procedure in some patients. Cumulative healing rates at 1, 3, 6, and 12 months were 82.1%, 92.5%, 92.5%, and 97.4%, respectively. No ulcer had recurred at 1 year, but ulcers recurred in five patients at 14, 14, 23, 35, and 52 months after EVLT, respectively. One patient with a nonhealing ulcer 2 years after treatment developed well differentiated squamous cell carcinoma. CONCLUSIONS Ulcer epithelization occurred with continued GSV occlusion and loss of flow. Most ulcers healed within 3 months with no recurrence at 1 year. Nonhealing ulcers should undergo biopsy to exclude malignant transformation.

Radioembolization with Infusion of Yttrium-90 Microspheres into a Right Inferior Phrenic Artery with Hepatic Tumor Supply Is Feasible and Safe

PURPOSE To evaluate the feasibility and safety of yttrium-90 ((90)Y) radioembolization through the inferior phrenic arteries (IPAs). MATERIALS AND METHODS Retrospective analysis of 108 patients referred for radioembolization to treat primary (n = 103) or secondary (n = 5) liver malignancy was performed. Five patients had malignant hepatic tumors supplied by the IPA and met criteria for infusion of (90)Y spheres into the IPA. Digital subtraction angiography (DSA), catheter-directed computed tomographic (CT) angiography, and technetium-99m ((99m)Tc) macroaggregated albumin (MAA) single photon emission CT (SPECT)/CT were used to plan treatment. Bremsstrahlung SPECT/CT was performed 1 day after radioembolization. Follow-up included clinical and biochemical tests and cross-sectional CT or magnetic resonance imaging. RESULTS Parasitized extrahepatic arteries were detected in 37% of patients (n = 40). Of these, 62.5% (n = 25) had tumor supply through an IPA. Of the patients with IPA supply, 20% (n = 5) underwent infusion of (90)Y into the right IPA. Reasons for disqualifying patients from infusion into the IPA were less than 10% tumor supply (n = 11), failed catheterization of IPA (n = 3), arterioportovenous shunt (n = 2), failed identification of IPA on pretreatment angiography (n = 1), and gastric or esophageal enhancement on catheter-directed CT angiography (n = 3). In all five patients, technical success was demonstrated on (90)Y imaging, with no significant extrahepatic radionuclide activity. No adverse events related to IPA radioembolization occurred at mean follow-up of 4.5 months (range, 2.2-10.1 mo). CONCLUSIONS Delivery of (90)Y microspheres through the right IPA is feasible and safe with the use of catheter-directed CT angiography in addition to DSA and (99m)Tc MAA SPECT/CT in patients with tumors with greater than 10% IPA supply.

Bare nitinol stent enabled recanalization of long-segment, chronic total occlusion of superficial femoral and adjacent proximal popliteal artery in diabetic patients presenting with critical limb ischemia

PURPOSE To evaluate our experience of limb salvage with bare nitinol stent enabled recanalization of long length occlusions of superficial femoral artery (SFA) and adjacent proximal popliteal artery (PPA) in diabetic patients. METHODS A total of 573 patients underwent 842 lower limb interventions from August 2006 to September 2008 at our institute. A retrospective review was done of diabetic patients undergoing recanalization of long length SFA/adjacent PPA (>10 cm) occlusions with self expanding bare nitinol stents evaluating their impact on limb salvage. RESULTS Forty-four patients (mean age 65.2 years, M:F 25:19) underwent 49 long-length (>10 cm) SFA/PPA stenting procedures over a period of 26 months. Diabetics comprised 66% of patients (n=29, mean age: 63.7 years, M: F 19:10). The infrapopliteal distal run-off in this diabetic subgroup comprised one vessel (n=14/29, 48%), two vessels (n=12/29, 41%), and three vessels (n=3/29, 10%). The spectrum of critical limb ischemia included rest pain (n=8), ulcer (n=7) and gangrene (n=14). The lengths of occlusions recanalized were 10-39 cm. A total of 58 stents (individual length 10-17 cm, average diameter 6 mm, mean 2 stents per patient) were placed with average length of stented segment being 23.8 cm. Four patients had stents placed through ipsilateral popliteal artery approach with rest placed through femoral artery approach. Significant complications of the procedure included distal embolization (n=3) successfully managed with thrombolysis and popliteal arteriovenous fistula in one patient undergoing recanalization through popliteal approach, managed with covered stent placement. No procedure related mortality occurred during thirty-day follow-up period. All were followed up over an average duration of twelve months post-procedure. Three patients died due to associated medical conditions during this period. The following amputations were done on follow-up (three toe amputations, five forefoot amputations, three below-knee amputations, two above-knee amputations). The overall limb salvage rate was 80%. CONCLUSION Our study shows beneficial result of SFA/PPA stent placement in diabetic occlusions with significant concomitant infrapopliteal disease.

Radioembolization After Portal Vein Embolization in a Patient with Multifocal Hepatocellular Carcinoma

Radioembolization is an effective locoregional therapy for patients with intermediate or advanced stage hepatocellular carcinoma (HCC). It has been shown that radioembolization is safe in patients with portal vein thrombosis. This case report describes safe radioembolization after portal vein embolization in a patient with multifocal HCC.

Diagnosis and Management of Complications from Percutaneous Biliary Tract Interventions

Complications related to percutaneous biliary tract interventions (PBTIs) can range from access site discomfort to life-threatening vascular complications. These complications are relatively uncommon, and most of them are self-limiting. However, major complications for which an increased level of patient care and/or a prolonged hospital stay are required and that may lead to death-albeit rarely-can occur. Some of the most common complications related to PBTI include pain, infection, bile leakage, and catheter blockage. These conditions can be easily recognized by using the patients clinical history and laboratory examination results. However, the more uncommon complications, such as life-threatening hemobilia, acute pancreatitis, and catheter and stent fractures, may have nonspecific clinical manifestations, and the underlying pathologic condition may be found only when it is being sought specifically. It is important that diagnostic and interventional radiologists be aware of the wide spectrum of PBTI-related complications, as early recognition and treatment may prevent catastrophic situations. In addition, knowledge of the different treatment options is essential for guidance in interventional radiology procedures such as transarterial control of hemobilia, imaging-guided direct percutaneous embolization of pseudoaneurysms, and percutaneous treatment of catheter- and stent-related complications such as fractures. The authors review a wide spectrum of complications associated with PBTI and the percutaneous management of these conditions. They also highlight valuable lessons learned from morbidity and mortality rounds at a high-volume tertiary care center. ©RSNA, 2017.