F-18 FDG PET/CT Imaging in Normal Variants, Pitfalls and Artifacts in the Abdomen and Pelvis

Since its introduction into clinical practice, multimodality imaging has revolutionized diagnostic imaging for both oncologic and non-oncologic pathologies. 18F-fluorodeoxyglucose (18F-FDG) PET/CT imaging which takes advantage of increased anaerobic glycolysis that occurs in tumor cells (Warburg effect) has gained significant clinical relevance in the management of most, if not all oncologic conditions. Because FDG is taken by both normal and abnormal tissues, PET/CT imaging may demonstrate several normal variants and imaging pitfalls. These may ultimately impact disease detection and diagnostic accuracy. Imaging specialists (nuclear medicine physicians and radiologists) must demonstrate a thorough understanding of normal and physiologic variants in the distribution of 18F-FDG; including potential imaging pitfalls and technical artifacts to minimize misinterpretation of images. The normal physiologic course of 18F-FDG results in a variable degree of uptake in the stomach, liver, spleen, small and large bowel. Urinary excretion results in renal, ureteric, and urinary bladder uptake. Technical artifacts can occur due to motion, truncation as well as the effects of contrast agents and metallic hardware. Using pictorial illustrations, this paper aims to describe the variants of physiologic 18F-FDG uptake that may mimic pathology as well as potential benign conditions that may result in misinterpretation of PET/CT images in common oncologic conditions of the abdomen and pelvis.

Causes of Removal of metallic hardware employed in oral and maxillofacial surgery - A cross sectional survey.

Objective: This study was conducted to evaluate the causes of removal of titanium bone plates used routinely in maxillofacial region. Study Design: Cross Sectional Survey. Setting: Department of Oral & Maxillofacial Surgery, Armed Forces Institute of Dentistry (AFID). Period: January 2016 to June 2018. Material & Methods: A total of 60 patients previously operated in maxillofacial surgery department with open reduction and internal fixation with tru-dynamic titanium plating system in Operation Theater, who reported with complaints due to metallic hardware were included in the study. Data was collected regarding age, gender, time between plate insertion and removal, cause and site of plate removal was also recorded for each patient. Data was analyzed using SPSS 23.0 version. Results: During the study period, 60 patients underwent titanium plate removal out of which 34 were male and 26 were females. Most common cause of plate removal was infection followed by non-union. Majority of plates (43.3%) were removed within 6 to 12 months of insertion. Mandible was found to be the most common site of plate removal (60%). Gender was significantly associated with causes while age was associated with cause, site and duration of removing the metallic plates (P-Value, < 0.05). Conclusion: Removal of symptomatic titanium plates is likely to occur within first year of insertion. Infection was identified as the most common cause for removing the metallic plates.

Multiply Broken Metallic Hardware Removal for United Patella Fracture Applied Twenty Years Before: A Case Report

Breakage of tension band wires, used to treat the patella fracture, is not uncommon several years after the fracture fixation. Broken wires may migrate to surrounding neurovascular structures, other vital organs like heart and may cause potentially fatal complications. Once the wires have been broken, it is very difficult to remove the broken pieces of metal wires. We report a 50 years old male patient with broken tension band wires at multiple sites for patella fracture. The broken wires were removed 20 years after the initial surgery without any undue complications, however patient sustained significant soft tissue damage to remove all the pieces of broken wires that would otherwise have been removed without any undue complications immediately after fracture union.

A Retrospective Review of Spinal Radiofrequency Neurotomy Procedures in Patients with Metallic Posterior Spinal Instrumentation – Is it Safe?

Background: Recent studies have shown that medial branch radiofrequency neurotomy (RFN) procedures done at the level of a pedicle screw can increase pedicle screw temperature, and it has been speculated that pedicle screw heating may cause thermal injury. There has been a limited amount of investigation into the real-world safety profile of RFN procedures in patients with pedicle screws. Objectives: We aim to demonstrate that the occurrence of serious adverse events is rare for a medial branch RFN procedure completed at a level with metallic spinal hardware when performed according to the Spine Intervention Society practice standards. Study Design: This study involved retrospective chart reviews of every patient who received an RFN procedure for spinal facet joint pain during the 5-year time period from 2012-2016. Setting: The research took place within a single university-based interventional pain management center. Methods: The study sample included 507 patient charts. Data collection included patient demographics, RF denervation sites at a level with metallic hardware, and all serious RF-related complications that could be attributable to heated metallic hardware. The research team developed medical-chart abstraction criteria for each of the following categorized complications: a) superficial burns, b) deep burns, c) denervation of dorsal ramus, d) denervation of ventral ramus, and e) coagulation of a spinal vascular structure. Results: Of the 36 patients who met the inclusion criteria for this study, 43.6% were men and 56.4% were women. The mean age was 59.5 years old, with an age range of 25 to 87 years. There were a total of 56 ablations performed at a level with metallic spinal hardware, of which 11 were cervical, 44 were lumbar, and 1 was thoracic . There were zero documented complications found among our patient population in any of the 5 categories of serious complications. Limitations: As a retrospective chart review, this study was dependent on the availability and accuracy of medical records. Chart abstraction criteria for each outcome measure were developed by the research team without scientific testing. Conclusions: There have been no reported complications attributable to hardware temperature increases when performing medial branch RFNs at the level of a pedicle screw. For safety, it is important to use multiplanar fluoroscopic imaging techniques to ensure that the RFN cannula is not in contact with the pedicle screw. Key Words: Radiofrequency neurotomy, medial branch nerve ablation, safety, thermal injuries, metallic spinal hardware, pedicle screws, lateral mass screws, cervical facet joints, severe complications, adverse events

Ankle and Foot Injections: Ultrasound

Ultrasonography can be highly useful in diagnosing and treating common musculoskeletal conditions affecting the foot and ankle, ranging from plantar fasciitis to osteoarthritis of the metatarsophalangeal joint of the great toe, as well as uncommon ones such as impingement of a tendon or nerve by fixation screw. One of the greatest advantages of ultrasonography is its high resolution for muscle, tendon, nerve, and bony surfaces and the opportunity to simultaneously identify, image, and evaluate tender structures. It can be used in a clinic setting and in the presence of metallic hardware. The short-axis injection approach is best for superficial, vertically oriented joints such as the cuneiform-metatarsal joints, whereas the long-axis approach is best for relatively deeper structures such as the tibiotalar joint and when it is important that the needle be visualized at all times, such as when performing a tibial nerve block.