MRS370: Radiological Imaging 2 CASE STUDY Courtney Lovick: 11569167 Due date: 30 May 2016 Word count: 2,190 (excluding section headings, references, tables and figures) I declare that all material in this assignment is my own work except where there is clear acknowledgement or reference to the work of others. I am aware that my assignment may be submitted to plagiarism detection software, and might be retained on its database. Courtney Lovick (11569167) Assessment Task 3: Case Study 1 Contents Page Radiographic Abbreviations 2 Introduction 3 Patient Considerations Patient history 3 Patient preparation and care 4 Biological Considerations Anatomy and physiology 5 Pathology 6 Differential diagnosis 7 Technical Considerations Examination description 8 Complications 9 Alternative procedures 10 Summary Patient follow up 10 Examination evaluation 11 Conclusion 11 Reference List 12 Appendices Appendix 1: Request forms 13 Appendix 2: Patient radiographs 16 Appendix 3: Radiologist reports 22 Courtney Lovick (11569167) Assessment Task 3: Case Study 2 Radiographic Abbreviations Table 1: A clarification of the radiographic abbreviations used in this case study CR Central Ray CT Computed Tomography DOB Date of Birth DP Dorsoplantar DPO Dorsoplantar Oblique DR Digital Radiography ED Emergency Department IR Image Receptor kVp Kilovolt Peak mA Milliampere mAs Milliampere second MRI Magnetic Resonance Imaging ORIF Open Reduction Internal Fixation ROI Region Of Interest SID Source-to-Image receptor Distance TMT Tarsometatarsal Courtney Lovick (11569167) Assessment Task 3: Case Study 3 Introduction This case summary discusses the radiographic examination of one patient’s condition that was encountered during my time on clinical placement 3A. A 26 year old female presented to ED after falling down a set of concrete stairs earlier that day. She had been complaining of immediate right foot pain over the metatarsal region and was unable to weight-bear. The patient was referred to radiology for planar imaging to investigate the presence of a fracture. CT imaging was later utilised to further evaluate the extent of the injury. With the support of academic literature and pertaining to departmental protocol, all relevant details concerning patient, biological and technical considerations have been explored. A de-identified copy of the radiographs, request form and radiologist’s report have also been included in this summary. Patient Considerations Patient history Planar imaging of the foot for trauma should only be performed in the event of true bony tenderness (Carver & Carver, 2012, p. 79). Following an assessment of the patient’s symptoms, including pain, swelling and the inability to weight-bear, the referring physician requested a standard series of plain film x-rays for the right foot (appendix 1, figure 2). The patient presented for initial imaging in a department provided wheelchair. The acquired projections indicated high suspicion of fracture over the base of the second metatarsal, and a radiographer alert was provided for the reporter (appendix 2, figures 5, 6 & 7). No conclusive evidence of fracture or dislocation was established by the radiologist (appendix 3, figure 14) and the patient was cleared and sent home without management. The patient returned a week later, complaining of persistent bony tenderness in the same area. She was referred by orthopaedics for repeat imaging, and this time bilateral weight-bearing views were requested (appendix 1, figure 3). These are effective for comparison and accentuation of any sites of fracture or dislocation (Raby, Berman, Morley, & de Lacey, 2015, p. 306). Secondary assessment determined that quite a severe fracture had in fact been missed by the radiologist (appendix 3, figure 15). According to the American Academy of Orthopaedic Surgeons, extremity fractures are the second most frequently missed diagnosis in medicine (Ha, Porrino, & Chew, 2014, p. 492). A study Courtney Lovick (11569167) Assessment Task 3: Case Study 4 of overlooked fractures in ED found that 53% of initially missed fractures occur in the lower extremity, with the foot being the most commonly misdiagnosed location (Ha et al., 2014, p. 492). Investigation into the patient’s records found no history of previous imaging in the system. Extra consideration was given in obtaining a full history from the patient herself. She confirmed that she had no past experience of significant trauma or abnormalities in the lower right limb. The patient’s aggravated attitude in having to return for further imaging following delayed diagnosis suggested for a more mindful patient interaction (Ahrberg, Leimcke, Tiemann, Josten, & Fakler, 2014, p. 1). Patient preparation and care Radiographers are involved in the care of sick patients so infection control and standard hygiene practices are paramount (Frank et al., 2012, p. 15). Before the patient entered the room for both first and second presentation x-rays it was appropriately tidied, set-up and cleaned. All equipment was wiped down with a disinfectant cloth, linen exchanged, IR placed on the table, tube moved into an approximate position, standard exposure factors set, and all preliminary computer processes were completed to aid efficiency. I applied alcohol-based hand sanitizer to prevent spread of disease. Once the patient had been collected from the waiting room I introduced myself and my supervisor. Patient identity was confirmed with full name, DOB and verification of the ROI. Department protocol involved verbally requesting the pregnancy status of any woman between the ages of 15 and 50. Once this was denied I instructed her to remove her sock to eliminate artefact. After obtaining patient consent I proceeded to give a brief procedural explanation. I spoke in language appropriate for non-medical comprehension in an uncondescending tone, avoiding jargon. Obtaining patient cooperation was not an issue for this examination, however positive reinforcement, patience and empathy is always important for those suffering stress and pain (Lang, 2012, p. 116). Whilst positioning the patient, I allowed her to do as much of the moving as possible. I obtained verbal approval before touching the patient when appropriate for emphasis and palpation. When the patient presented for her CT appointment the following week many of the above patient considerations were also applied. The room was cleaned and set up prior to her arrival and patient ID and pregnancy status confirmed. No requirement of the removal of artefact or the use of intravenous contrast saw the patient preparation for this examination to be simple and efficient. Courtney Lovick (11569167) Assessment Task 3: Case Study 5 Biological Considerations Anatomy and physiology The skeleton of the foot consists of 26 bones, each of which are effectively structured to propel the body forward and support its weight (Marieb & Hoehn, 2011, p. 241). These include 7 bones of the tarsus, 5 bones of the metatarsus and 14 phalanges (Frank, Long, & Smith, 2012, p. 228). Figure 1 demonstrates the normal radiographic appearance of bony foot anatomy, as seen on a DP x-ray. Figure 1: DP x-ray of the right foot demonstrating normal radiographic appearance with annotated bony anatomy and their articular relationship with the joints (Carver & Carver, 2012, p. 80). Courtney Lovick (11569167) Assessment Task 3: Case Study 6 The five metatarsals form the proximal aspect of the forefoot and are numbered one to five beginning medially (Frank, et al., 2012, p. 229). They are small, long bones consisting of a tubular shaft referred to as the body, an expanded proximal articular end called the base, and a rounded distal articular end termed the head (Christman, 2015, pp. 51, 55). The fourth and fifth metatarsals articulate with the cuboid, whereas the first, second and third metatarsals articulate with the medial, middle and lateral cuneiform respectively (Manaster, May, & Disler, 2013, p. 235). The parallel, convex arrangement of the metatarsals is functionally appropriate for balance, rotational stability and translation of force (Marieb & Hoehn, 2011, p. 242). The second metatarsal base lies proximal and dorsal to the bases of the other metatarsals, ensuring the proper position of surrounding bones (Manaster et al., 2013, p. 235). The second metatarsal base is supported by the strong Lisfranc ligament, which, according to Manaster et al. (2013), “connects the lateral-distal margin of the medial cuneiform with the adjacent medial-proximal margin of the second metatarsal”. The tarsometatarsal articulation is appropriately termed the Lisfranc joint. The Lisfranc joint promotes energy dissipation by allowing force to be transferred between the midfoot and the forefoot (Englanoff, Anglin, & Hutson, 1995, p. 230). Pathology The pathology under investigation was the presence of a fracture in the mid/forefoot (appendix 1, figure 2). The obvious break in bony cortex and discontinuity of trabeculae pattern illustrated by both DP and DPO x-rays is radiographically suggestive of fracture. While no abnormality could be detected with planar imaging at first, the radiologist’s final report (appendix 3, figure 16) identifies a comminuted intra-articular fracture at the base of the right second metatarsal, with dorsal-medial displacement of the bony fragment. The subtle malalignment between the first and second TMT articulations demonstrated with CT imaging (appendix 2, figure 13) is indicative of Lisfranc fracture-dislocation. CT proved to be more effective in demonstrating the full extent of the injury. A Lisfranc injury is a relatively infrequent traumatic subluxation or dislocation at the base of the metatarsals at the TMT joints, and can occur with or without a fracture (Raby et al., 2015, p. 302). Injuries of the Lisfranc joint should always be investigated whenever a fracture of the base of any of the medial four metatarsals is present, due to the suspicion of ligamentous rupture and associated Courtney Lovick (11569167) Assessment Task 3: Case Study 7 avulsion at points of insertion (Raby et al., 2015, p. 302). A Lisfranc fracture-dislocation typically occurs in the setting of axial loading of the plantar-flexed foot, such as tripping when coming down stairs (Manaster et al., 2013, p. 240). Lisfranc injuries are often overlooked on radiographs due to medical failure of satisfaction of search, or lack of distinction due to non-weight-bearing images causing injury to be radiographically occult as the joint is not under stress (Raby et al., 2015, p. 303). Differential diagnosis Apart from fractures of the bone, acute foot pain and the inability to weight-bear as a result of minimal trauma could be the consequence of sprained ligaments, strained muscles or inflamed joints (Raby et al., 2015, p. 298). A commonly encountered fracture involves the base of the fifth metatarsal, which accounts for 70% of all metatarsal fractures (Raby et al., 2015, p. 298). A fracture of the tubercle of the fifth metatarsal is resultant of an inversion injury caused by a plantar flexion-inversion injury (Raby et al., 2015, p. 298). This should not be confused with a Jones’ fracture, which is a transverse fracture that lies distal to the styloid process of the fifth metatarsal, resulting from mediolateral force or repeated stress (Raby et al., 2015, p. 301). Other differential diagnoses include cuneiform avulsion fractures associated with Lisfranc injury, March fractures of the metatarsals if the patient had suffered repetitive impact to this region, fracture of the calcaneus or body of the talus if the patient’s fall was from a considerable height, or a Pott’s fracture of the distal fibula and medial and lateral malleoli if mechanism of injury involved outward and backward displacement of the leg while the foot was fixed (Marieb & Hoehn, 2011, p. 214). Courtney Lovick (11569167) Assessment Task 3: Case Study 8 Technical Considerations Examination description The department utilised a Siemens Ysio DR system with a 35x43cm IR. ED protocol for first presentation x-rays of acute foot trauma suggests three standard x-ray projections: DP, oblique and lateral. Exposures of 57kVp, 277mA and 0.009s (2.5mAs) were deemed appropriate for both DP and DPO projections, and were increased to 60kVp, 292mA and 0.011s (3.2mAs) for the lateral to compensate for increased anatomical thickness. All images were acquired out of bucky with an SID of 100cm. No gonad shielding was utilised as per departmental preference. The first view obtained was a DP foot (appendix 2, figure 5). The table was lowered for easier wheelchair translation before being raised for correct manual handling. The patient was asked to lie in a supine position and a pillow placed under her head. She was instructed to flex her right knee, placing the planter aspect of her foot in contact with the IR (lengthwise). After ensuring no rotation, a 15-degree cranial angle was applied to the tube to account for her high arch and for clearer visualisation of tarsal joint spaces, while the CR was centred perpendicular to the IR at the base of the third metatarsal (Frank et al., 2012). The beam was collimated to include all soft tissue margins. The second projection performed was a DPO foot (appendix 2, figure 6). From the previous position, the patient was asked to medially rotate her knee so that the plantar aspect of the foot formed an angle of 30-degrees to the plane of the IR (Frank et al., 2012, p. 258). A radiolucent sponge was placed under the lateral aspect of the foot for immobilisation. The 15-degree angle was removed from the tube while all other factors remained constant. Finally, a mediolateral projection was acquired (appendix 2, figure 7). The patient was asked to roll onto her right hip and the lateral aspect of her foot was placed in contact with the IR. With the leg extended and the foot in dorsiflexion, a sponge was placed beneath the patella to achieve true lateral position of the leg. Once again the CR was centred perpendicular to the base of the third metatarsal and collimation was appropriate to include skin edges and 2cm above the medial malleolus. When the patient returned for repeat imaging in the week following bilateral weight-bearing views were achieved. These images should always be obtained where there is clinical concern regarding Lisfranc injury, as the stress emphasises any diastasis in normal bony architecture (Carver & Carver, 2012, p. 82). The patient was asked to stand on a specially designed radiolucent platform with her Courtney Lovick (11569167) Assessment Task 3: Case Study 9 weight distributed as evenly as possibly. The IR was placed beneath the platform for the DP and DPO views, and vertically in a groove between the feet for the lateral. DP views of both feet were acquired in one projection (appendix 2, figure 8), whereas DPO and lateral views were performed separately for each foot (appendix 2, figures 9 & 10). Exposure factors, SID, beam angle, centring and collimation remained the same as the initial standard projections. Although conventional radiography was effective in providing evidence of Lisfranc fracture- dislocation and was able to rule out other pathologies, a CT examination was ordered to give a more accurate understanding of the extent of the comminuted fracture, and evaluate disruption of joints prior to surgical intervention (appendix 1, figure 4). The higher anatomic detail produced from cross- sectional images is more effective in representing the condition (appendix 2, figures 11, 12 & 13). The department utilised a Siemens Somatom Sensation 64 slice scanner. A non-contrast foot scan was performed with the patient feet first in a supine position, with feet in the foot holder and toes pointed upwards. The scan range was set to include all anatomy from the syndesmosis to below the calcaneus. The scan and reconstruction parameters followed for this case is summarised in Table 2. Table 2: Department protocol for a CT foot scan as acquired from clinical placement site 3A Scan Type Spiral Cranio-caudal direction Exposure Factors 120kV 200 effective mAs 1.0s rotation time Pitch Value 1 Slice Thickness and Interval 0.4mm x 0.3mm Reformation Requirements Axial 3mm x 3mm bony algorithm Coronal 3mm x 3mm bony algorithm Sagittal 3mm x 3mm bony algorithm *all planes relative to first metatarsal Complications Overall, the patient was happy to cooperate and the three examinations were carried out with minimal difficulty. A noteworthy complication encountered during initial presentation was with the accompaniment of her child. The child was unaccustomed to her immobility and was reluctant to leave her side. It took convincing from both mother and radiographer to persuade the child to stay behind the lead screen for each exposure. The patient presented to the subsequent examinations solo. Courtney Lovick (11569167) Assessment Task 3: Case Study 10 Alternative procedures A combination of CT and conventional radiography was sufficient in the diagnosis of this patient’s condition, so she was not referred for additional imaging. While CT and x-ray are often effective in the initial detection Lisfranc associated diastasis and fractures, they are sometimes inconclusive. If clinical suspicion of osseous injury persists or further imaging is warranted for the assessment of ligamentous integrity, there is a role for MRI, nuclear medicine and ultrasound. MRI is regarded as the criterion standard for sensitivity and specificity of injuries to the Lisfranc joint complex and surrounding soft tissues, and most accurate in disclosing the degree of ligamentous disruption (Potter, Deland, Gusmer, Carson, & Warren, 1998, p.438). Its expense and availability, however, usually does not make it the initial imaging study performed. Radionuclide bone scans will often show abnormal radiotracer uptake in patients with midfoot injuries and are most helpful for detection of low-grade injuries when radiographic findings are normal or equivocal (Siddiqui, Galizia, Almusa, & Omar, 2014, p. 524). However, while bone scintigraphy gives 100% sensitivity, it is non-specific and should be used in conjunction with other modalities to rule out pathologies such as infection or arthritis which may also demonstrate radioisotope hotspots. Ultrasonography is also clinically useful with its ability to assess the dorsal Lisfranc ligament and TMT subluxation, although is limited in its ability for assessing deeper structures (Siddiqui, Galizia, Almusa, & Omar, 2014, p. 525). Summary Patient follow up Once the radiologist’s final diagnosis was made, and in collaboration with orthopaedic surgeons, it was decided that the patient would undergo surgery for an ORIF. This would involve the introduction of multiple plates and screws between the first and second metatarsal and across the first and second TMT joints for the realignment of joints and fracture fragments. My time on clinical placement terminated before I could learn of patient recovery, however it is expected that the patient’s injuries would be immobilised by a short leg cast for around 6-8 weeks before the patient would be ambulant again (Hu, Chang, Li, & Yu, 2014, p.317). Patients are not expected to achieve a level of intense athletic activity for at least 6-8 months following surgery (Hu et al., 2014, p. 317). Courtney Lovick (11569167) Assessment Task 3: Case Study 11 Examination evaluation All images produced for this patient’s injury were of diagnostic quality without the necessity of repeat exposure (appendix 2). Both initial and second presentation x-ray series demonstrate all relevant anatomy in positions adequate for radiologist assessment. Image density and contrast is acceptable for visualisation of bony detail including the abnormal break in bony cortex and discontinuation of trabecular pattern. The foot appears slightly foreshortened in the weight-bearing DPO projection of the right foot upon second presentation. This could be improved by ensuring the central beam is 90o to the IR in order to avoid anatomical distortion. The CT images are of high quality and demonstrate the fracture-dislocation well. Due to my limited exposure in CT imaging I felt less confident in taking part in this examination. I feel that my patient care and communication skills in CT requires improvement, which will progress with greater experience in this area. Conclusion This case study has discussed both plain film and CT examinations of the foot. It has included patient, biological and technical considerations with emphasis on care, pathology and procedural analysis. The case involved an example of misdiagnosis, and highlighted the role of additional imaging with a second, more advanced imaging modality when confronted with an injury that continues to hold clinical suspicion and requires further information regarding its extent and preoperative planning. The study demonstrated how theoretical knowledge is carried into physical practice and the importance of image analysis in every examination. Courtney Lovick (11569167) Assessment Task 3: Case Study 12 Reference List Ahrberg, A.B., Leimcke, B., Tiemann, A.H., Josten, C., & Fakler, J.K. (2014). Missed foot fractures in polytrauma patients: a retrospective cohort study. Patient Safety in Surgery, 8(10), 1-6. http://doi.org/10.1186/1754-9493-8-10 Carver, E., & Carver, B. (2012). Medical imaging: techniques, reflection and evaluation. (2nd ed.). Edinburgh: Churchill Livingstone. Christman, R.A. (2015). Radiographic anatomy of the foot and ankle - part 4. Journal of the American Podiatric Medical Association, 105(1), 51-60. doi: http://dx.doi.org/10.7547/8750-7315-105.1.51 Englanoff, G., Anglin, D., & Hutson, R. (1995). Lisfranc Fracture-Dislocation: A Frequently Missed Diagnosis in the Emergency Department. Annals of Emergency Medicine, 26, 229-233. Frank, E.D., Long, B.W, & Smith, B.J. (2012). Merrill’s atlas of radiographic positioning and procedures: Vol. 1. (12th ed.). Philadelphia: Mosby Elsevier. Ha, A.S., Porrino, J.A., & Chew, F.S. (2014). Radiographic pitfalls in lower extremity trauma. American Journal of Roentgenology, 203(3), 492-500. Hu, S., Chang, S., Li, X., & Yu, G. (2014). Outcome comparison of Lisfranc injuries treated through dorsal plate fixation versus screw fixation. Acta Ortopedica Brasileira, 22(6), 315–320. http://doi.org/10.1590/1413-78522014220600576 Lang, E.V. (2012). A better patient experience through better communication. Journal of Radiology Nursing, 31(4), 114–119. http://doi.org/10.1016/j.jradnu.2012.08.001 Manaster, B.J., May, D.A., & Disler, D.G. (2013). Musculoskeletal imaging: the requisites. (4th ed.). Philadelphia: Saunders Elsevier. Marieb, E.N., & Hoehn, K. (2011). Human anatomy & physiology. (9th ed.). San Francisco: Pearson Benjamin Cummings. Potter, H.G., Deland, J.T., Gusmer, P.B., Carson, E., Warren, R.F. (1998). Magnetic Resonance Imaging of the Lisfranc ligament of the foot. Foot & Ankle International, 19(7), 438-446. Raby, N., Berman, L., Morley, S., & de Lacey, G. (2015). Accident & Emergency Radiology. (3rd ed.). Edinburgh: Saunders Elsevier. Siddiqui, N.A., Galizia, M.S., Almusa, E., & Omar, I.M. (2014). Evaluation of the tarsometatarsal joint using conventional radiography, CT and MR imaging. Radiological Society of North America, 34(2), 514-531. Courtney Lovick (11569167) Assessment Task 3: Case Study 13 Appendices Appendix 1: Request forms i. Initial presentation x-rays Figure 2: Copy of referral for initial x-ray imaging after first presentation to Emergency Department Courtney Lovick (11569167) Assessment Task 3: Case Study 14 ii. Second presentation x-rays Figure 3: Copy of referral for follow-up x-rays after returning to the hospital with recurrent pain Courtney Lovick (11569167) Assessment Task 3: Case Study 15 iii. CT imaging Figure 4: Copy of referral for CT imaging for assessment of the extent of injury prior to surgery Courtney Lovick (11569167) Assessment Task 3: Case Study 16 Appendix 2: Patient Radiographs i. Initial presentation x-rays Figure 5: DP projection of the right foot demonstrating all anatomy from the terminal tufts of the distal phalanges to the distal tibia and fibula, including soft tissue margins laterally Figure 6: DPO projection of the right foot demonstrating all anatomy from the terminal tufts of the distal phalanges to the distal tibia and fibula, including soft tissue margins laterally Courtney Lovick (11569167) Assessment Task 3: Case Study 17 Figure 7: Mediolateral projection of the right foot demonstrating all anatomy from the terminal tufts of the distal phalanges to the calcaneum, including soft tissue margins laterally ii. Second presentation x-rays Figure 8: DP projection of bilateral feet during weight-bearing demonstrating all anatomy from the terminal tufts of the distal phalanges to the navicular bilaterally, including lateral skin edges Courtney Lovick (11569167) Assessment Task 3: Case Study 18 Figure 10: Mediolateral weight-bearing projection of the right foot demonstrating all anatomy from the terminal tufts of the distal phalanges to the calcaneum, including surrounding soft tissues Figure 9: DPO weight-bearing projection of the right foot demonstrating all anatomy from the terminal tufts of the distal phalanges to the distal tibia and fibula, including soft tissue margins laterally Note: Not all diagnostic images acquired during the second examination have been included for the purposes of this case study. Weight-bearing DPO and lateral projections of the left foot were additionally obtained for radiologist comparison but the utilisation of these images in the case study has been deemed unnecessary in providing further supporting information Courtney Lovick (11569167) Assessment Task 3: Case Study 19 iii. CT imaging Figure 11: Sagittal CT slices demonstrating the full extent of the injury and fracture site from the more lateral aspect (1) to the more medial aspect (4) of the right foot Courtney Lovick (11569167) Assessment Task 3: Case Study 20 Figure 12: Axial CT slices demonstrating the extent of the injury and site of fracture/dislocation from the more inferior aspect (1) to the more superior aspect (4) of the right foot Courtney Lovick (11569167) Assessment Task 3: Case Study 21 Figure 13: Coronal CT slices demonstrating the extent of the site of fracture/dislocation from the more anterior aspect (1) to the more posterior aspect (4) of the right foot Courtney Lovick (11569167) Assessment Task 3: Case Study 22 Appendix 3: Radiologist Reports i. Initial presentation x-rays Figure 14: Radiologist’s conclusions in regards to x-rays upon initial presentation with foot pain ii. Second presentation x-rays Figure 15: Radiologist’s findings following second presentation to x-ray with prolonged foot pain Courtney Lovick (11569167) Assessment Task 3: Case Study 23 iii. CT imaging Figure 16: Radiologist’s report following CT examination for further evaluation of injury