Four-dimensional computed tomography (4DCT): A review of the current status and applications.

The applications of conventional computed tomography (CT) have been widely researched and implemented in clinical practice. A recent technological innovation in the field of CT is the emergence of four-dimensional computed tomography (4DCT), where a three-dimensional computed tomography volume containing a moving structure is imaged over a period of time, creating a dynamic volume data set. 4DCT has previously been mainly utilised in the setting of radiation therapy planning, but with the development of wide field of view CT, 4DCT has opened major avenues in the diagnostic arena. The aim of this study is to provide a comprehensive narrative review of the literature regarding the current clinical applications of 4DCT. The applications reviewed include both routine diagnostic usage as well as an appraisal of the current research literature. A systematic review of the studies related to 4DCT was conducted. The Medline database was searched using the MeSH subject heading 'Four-Dimensional Computed Tomography'. After excluding non-human and non-English papers, 2598 articles were found. Further exclusion criteria were applied, including date range (since wide field of view CT was introduced in 2007), and exclusion of technical/engineering/physics papers. Further filtration of papers included identification of Review papers. This process yielded 67 papers. Of these, exclusion of papers not specifically discussing 4DCT (cone beam, 4D models) yielded 38 papers. As part of the review, the technique for 4DCT is described, with perspectives as to how it has evolved and its benefits in different clinical indications.

Fetal MRI demonstrating vein of Galen malformations in two successive pregnancies--a previously unreported occurrence.

PURPOSE: Vein of Galen malformations are rare and are usually detected in utero using ultrasonography. No definite genetic predisposition has been described in the literature. We present a case with two successive pregnancies complicated by vein of Galen malformations, which were assessed using fetal MRI. The putative role of genetic mutations is also discussed. METHODS: A 30-year-old primigravida presented in the third trimester with a fetus diagnosed with vein of Galen malformation on sonography. MRI and MR angiography were performed for further assessment. The subsequent pregnancy was again complicated by vein of Galen malformation. In addition to MRI, genetic analysis was carried out on both fetuses and on the parents. RESULTS: MR angiography revealed that both fetuses suffered from the choroidal sub-type of vein of Galen malformation, with multiple arterial feeders fistulating onto a midline venous pouch. The visualised anatomy obtained was far superior than on sonography and allowed categorisation of vein of Galen malformation sub-type. Genetic analysis on the mother and both fetuses showed variant RASA1 gene mutation. CONCLUSIONS: This case demonstrates that fetal MRI is a powerful tool in the investigation of in utero neurovascular malformations. A genetic mutation was identified, but this was of uncertain significance.

Cardiac CT imaging in the context of left atrial appendage occlusion.

Left atrial occlusion devices are a recognized treatment option in patients with difficult to treat atrial fibrillation or intolerance to warfarin therapy. There are an increasing number of devices on the market, and good quality preoperative imaging is crucial to assess the feasibility of the procedure and help plan the occlusion. Electrocardiography-gated cardiac CT is ideal for this purpose as the high spatial and temporal resolution allow accurate measurements and reformats in multiple planes. As the imaging specialist reporting the CT may not necessarily be the interventionalist performing the implantation, this review will illustrate the important points in reporting the preimplant CT. The expected postoperative appearances and potential complications will also be described.

Tranexamic acid for spontaneous intracerebral hemorrhage: a randomized controlled pilot trial (ISRCTN50867461).

BACKGROUND: Spontaneous intracerebral hemorrhage (ICH) can be devastating, particularly if hematoma expansion (HE) occurs. Tranexamic acid (TA), an antifibrinolytic drug, significantly reduced mortality in bleeding patients after trauma in the large CRASH-2 trial. The CRASH-2 ICH substudy found that TA nonsignificantly reduced mortality and dependency in traumatic ICH. The aim of this study was to assess the feasibility of performing a randomized controlled trial of tranexamic acid in spontaneous ICH, ahead of a definitive study. METHODS: We performed a single-center, prospective, randomized (2:1), double-blind, placebo-controlled blinded endpoint trial of TA (intravenous 1 g bolus, 1 g infusion/8 h) in acute (<24 hours) spontaneous ICH. The primary objective was to test the feasibility of recruiting to the trial. Other objectives included tolerability (adverse events) and the effect of TA on HE and death and dependency. RESULTS: The trial was feasible, with 24 patients enrolled (TA, n=16; placebo, n=8) between March 2011 and March 2012, and acceptable-only 3 patients declined to participate. All patients received the correct randomized treatment; 1 patient in the TA group did not complete the infusion because of neurologic deterioration. There were no significant differences in secondary outcomes including adverse events, HE, death, and dependency. One patient in the TA group had a deep vein thrombosis . CONCLUSIONS: This, the first randomized controlled trial of TA in ICH, found that the protocol could be delivered on schedule (2 patients/mo) and was feasible. Larger studies are needed to assess safety and efficacy of TA in ICH.

Fracture mimics on temporal bone CT: a guide for the radiologist.

OBJECTIVE: The objective of this article is to discuss and illustrate commonly visualized fissures and sutures in the temporal bone. This topic is important because a thorough knowledge of normal anatomy is necessary to avoid misinterpretation as fractures. CONCLUSION: Small normal anatomic fissures are now routinely visualized with the increasing use of MDCT in trauma patients. An awareness of these structures is required by radiologists interpreting studies with fine temporal bone slices to prevent erroneous interpretation.

MDCT findings in Baastrup disease: disease or normal feature of the aging spine?

OBJECTIVE: Baastrup disease is characterized by the development of abnormal contact between adjacent spinous processes. The clinical significance remains unresolved, a few studies showing Baastrup disease as a cause of back pain. The aim of this study was to establish the frequency of Baastrup disease in a large unselected cohort to determine whether it is part of the expected spectrum of degenerative changes in the aging spine. MATERIALS AND METHODS: The abdominopelvic CT scans of 1008 patients divided equally into seven age groups were retrospectively reviewed. Baastrup disease was judged present if there was close contact between adjacent spinous processes and if the apposing ends were sclerotic. The presence of other degenerative changes, such as disk degeneration, spondylolisthesis, and facet osteoarthritis, at affected levels also was noted. RESULTS: Evidence of Baastrup disease was found in 413 patients (41.0%). A decade-on-decade increase in frequency was found with a peak of 81.3% among patients older than 80 years. As many as five levels were found to be affected in some patients (4.1% of 413), but in most patients (35.4%), one level was affected. Baastrup disease was most common at L4-L5. Associated degenerative changes were found at almost all affected levels (899/901). CONCLUSION: Baastrup disease occurs with high frequency among the elderly. Our data show that it develops with increasing age and is part of the expected degenerative changes in the aging spine. Because of the nearly universal association with other degenerative changes, we urge caution before diagnosing Baastrup disease as the cause of back pain.

Craniometric measurements in the assessment of craniovertebral settling: are they still relevant in the age of cross-sectional imaging?

OBJECTIVE: Craniovertebral settling is a serious complication of rheumatoid arthritis, and a number of radiographic measures at the craniocervical junction are in use to enable its diagnosis. However, these measures are hampered by the overlap of relevant bony landmarks. We aim to establish accurate values for these measures on CT to facilitate early diagnosis of this condition on cross-sectional imaging. MATERIALS AND METHODS: One hundred men and 100 women who underwent CT that included imaging of the craniocervical junction were retrospectively identified. Patients between the ages of 18 and 49 years were included. Two radiologists reformatted the images in the midsagittal plane and performed a series of measurements as follows: the Wackenheim line, McRae line, Chamberlain line, and McGregor line and measurements obtained using the Redlund-Johnell method and our modification of the method proposed by Ranawat et al. RESULTS: There were significant differences between the CT values and accepted radiographic measurements for the Wackenheim, Chamberlain, and McGregor lines. The McRae line was the easiest to measure, and the odontoid tip did not cross this line in any patient (distance from line: range, 0.6-10.4 mm). The CT measurements obtained using the Redlund-Johnell method were similar to the radiographic values, and we provide normal CT values for the modified Ranawat method (men > 23.7 mm, women > 24.2 mm). CONCLUSION: We propose that the McRae line should be used over other methods when assessing for craniovertebral settling on cross-sectional studies because it is the easiest measure to understand and remember. If the odontoid tip is eroded, the Redlund-Johnell and modified Ranawat methods are alternatives, and we have provided normal CT values for those measures as well.

MRI findings in herniation of the spinal cord.

Herniation of the spinal cord is a rare condition that causes non specific neurological deficits that are often a diagnostic challenge to clinicians. Despite several reports in the neurosurgical literature, it is only recently that the imaging appearances of this condition have come to be recognised, due mainly to the widespread adoption of spinal MRI. It is important for radiologists to recognise the telltale MRI features of this condition, as several cases have undergone initial misdiagnosis, resulting in delayed treatment We present a case with typical imaging features to familiarise radiologists with this condition, as it is likely that more cases will come to the fore, with more spinal MRIs being performed.

The use of a tantalum-based Augmentation Patella in patients with a previous patellectomy.

Patients with previous patellectomies for anterior knee pain syndrome, can remain symptomatic and develop osteoarthrosis or instability. We report our experience of the use of a novel implant to substitute for the absent native patella. Seven patients, with previous patellectomies, were treated with the Augmentation Patella (Zimmer, Allendale, USA). This implant was sutured to the patellar tendon, as part of a patello-femoral joint replacement (four cases) or total knee replacement (three cases). In three patients, the implant loosened and failed within 15 months. Two patients remained symptomatic despite solid fixation. One patient developed wound complications due to the bulk of the implant, and the procedure was abandoned in one patient as wound closure was not possible. The results of this implant in our patients with previous patellectomies have been disappointing. Previous studies where this implant has been used, have also shown high loosening and failure rates. We do not recommend its use to substitute for the absent patella.

Publication rate of Trauma abstracts presented at an International Orthopaedic conference.

INTRODUCTION: Oral presentations at major conferences are often used to present new material and generate discussion. However, conference abstracts that ultimately fail to be published are of little use to the wider medical community. The aim of this study was to evaluate the publication rate of trauma papers presented at an international orthopaedic conference, and to assess the factors which predict publication. METHODS: All abstracts presented orally at the trauma sessions of the European Federation of National Associations of Orthopaedics and Traumatology (EFORT) Congresses in 1999 (Belgium) and 2001 (Greece) were assessed. A MEDLINE and EMBASE search was performed to identify articles written by the first, second and last authors of each abstract to identify a matching journal article. Subspecialty, country of origin of abstract, study type, journal of publication and publication year were tabulated. RESULTS: Two hundred and seventy eight trauma abstracts were presented orally, and 112 (40.3%) achieved subsequent publication. Abstracts on fractures of the proximal femur were the most common (18.7%) and had one of the highest rates of publication (44.2%). Greece and the UK provided the largest number of abstracts, and randomised trials were the study type with the highest rate of publication (80.0%). Thirty two percent of journal articles appeared within 1 year of the conference and 63% within 2 years. Injury was the journal most likely to publish the articles. CONCLUSION: About 60% of Trauma abstracts presented did not result in a subsequent full-text publication. The citation of conference proceedings should be discouraged, and clinicians should be wary of implementing information gleaned from conference presentations into their clinical practice.

Severity of injuries associated with femoral fractures as a result of motor vehicle collisions.

INTRODUCTION: Femoral fractures are often the result of high-velocity injuries, and the early identification of associated injuries is important. The purpose of this study was to review the associated injuries present in a current UK series of patients who sustain femoral fractures as a result of motor vehicle accidents. MATERIALS AND METHODS: All cases of femoral fractures were extracted from the UK co-operative crash injury study (CCIS) database, from 1998 to 2002. Associated injuries, skeletal and non-skeletal, were identified by body region and severity (according to the abbreviated injury scale and injury severity scale). RESULTS: A total of 5,841 crashes were investigated in that time period, and there were 365 car occupants who sustained a femoral fracture. The 16-35 age group accounted for nearly half of all cases. A total of 313 patients (85.2%) had at least one other concomitant significant injury, of which 84 (23.0%) had skeletal injury only, 45 (12.3%) had non-skeletal injury only, and 184 (50.4%) had both. The opposite lower limb was the most common skeletal injury, and thoracic injuries were the most common visceral injuries. Thoracic injuries also accounted for the most serious injuries (AIS 4-6). The overall mortality was 40.5% in our series. CONCLUSION: Concomitant injuries are to be expected in the majority of cases of femoral fractures sustained as a result of MVCs. There should be a low threshold for involving a general surgical team in the management of these cases.

A case of traumatic testicular torsion associated with a ruptured epididymis.

To salvage the testis, most urological surgeons advocate early exploration of enlarging scrotal masses or suspected testicular ruptures resulting from trauma. A case of testicular torsion within a hematoma, following blunt testicular trauma is presented, and we suggest that another indication for exploring a scrotal mass following blunt injury is to help establish an early diagnosis of torsion of the testicle.