Reliability and accuracy of scout CT in the detection of vertebral fractures.

OBJECTIVE: The aim of the present study was to evaluate the reliability of scout CT (sCT) lateral radiograph, in terms of diagnostic accuracy and intra- and interobserver agreement in the detection of vertebral fractures (VFs). METHODS: 300 CT examinations of the thoracic and/or lumbar spine were collected and independently analysed by 3 musculoskeletal radiologists in 2 different sessions. A semi-quantitative approach was used for VF assessment on sCT, and morphometric analysis was performed when a VF was suspected. Results of multiplanar sagittal CT reconstructions interpreted by the most expert radiologist were considered as gold standard. Arthrosis was also scored. Only vertebral bodies assessable by both sCT and gold standard were considered for the analysis. Area under the receiver operating characteristic curve (AUROC), Cohen's kappa statistic and linear-by-linear association were used for statistical analysis. RESULTS: 1522 vertebrae were considered (130 males and 170 females; ages, 73.0±2.8 years). 73 of 1522 (4.8%) VFs were identified in 34/300 patients (11.3%). In the detection of VFs, the sensitivity and specificity of sCT were 98.7% and 99.7%, respectively. Accuracy (AUROC=0.992±0.008), as well as interobserver agreement (k=0.968±0.008), was excellent. Intra-observer agreement was perfect (k=1.000). Performance of this method was independent of arthrosis, vertebral level and type and grade of VFs. CONCLUSION: sCT is a simple but very accurate method for the detection of VFs. It should be introduced as a spine evaluation tool for the detection of VFs in examinations that are performed for other diagnostic purposes. ADVANCES IN KNOWLEDGE: sCT lateral radiograph is an accurate tool for the detection of VFs. This technique may be used with several advantages in clinical practice.

Preliminary experience with electromagnetic navigation system in TKA.

Accuracy of implant positioning and precise reconstruction of leg alignment offers the best way to achieve good long-term results in total knee arthroplasty. Computer instrumentation was developed to improve the final position of the component and restore the mechanical axis. Current navigation systems use either optical or electromagnetic tracking. The advantage of the Electromagnetic (EM) navigation system is that no line-of-sight issues are present. However, special iron-free instruments are required. This report analyzes the postoperative radiological results of 32 knees treated using an EM system. All the measurements were recorded using software able to subtend angles automatically by five physicians, three radiologist and two orthopedic residents not involved with the surgery. Each radiograph was measured three times, in random order, and at delayed intervals. We found an ideal alignment for the mechanical axis (180+/-3 degrees ) in 30 out of 32 cases, whereas all the patients achieved a value of 90 degrees +/-3 degrees for both femoral and tibial frontal component angles. An apparently over-corrected implant position for the sagittal femoral component was reported, with a mean value of 11.2 degrees +/-3.6. The mean position of the tibial component was 90.6 degrees +/-2.8; just four measurements were outside of the +/-3 degrees of the desired value. EM is safe and there were no complications related to this system. An almost perfect correlation was found between the mechanical axis value of the EM navigation system (179.8 degrees +/-1.8) and the median value of the all reviewers (180.3 degrees +/-1.9) with a difference of 0.5 degrees .

[Computerized tomography guided biopsy in the diagnosis of neoplastic and inflammatory lesions of the pelvis]. / La biopsia guidata con Tomografia Computerizzata nella diagnosi delle lesioni neoplastiche e infiammatorie del bacino.

PURPOSE: To assess the efficacy of percutaneous CT-guided biopsy in the diagnosis and therapeutic planning of neoplastic and flogistic diseases of the pelvis. MATERIAL AND METHODS: From July 1990 to December 1999 193 patients (113 males, 80 females: mean age 49, standard deviation 16) were submitted to CT-guided percutaneous biopsy of the pelvic region; 117 biopsies (61%) were performed at iliac, pubic and ischial segments and 76 (39%) at sacral region; 107 patients were admitted to the hospital and 86 were in clinic. Needles were 8 G (4 mm), 10 to 15 cm long. Approach to pelvic lesions was performed according to the specific site. Lesions of the lateral pelvic region have always been approached through the lateral surgical incision according to Enneking. Lesions of the posterior pelvic region have always been approached by the introduction of the needle along the posterior surgical incision according to Enneking. Lesions of the anterior region have always been approached through the anterior surgical incision according to Enneking. From July 1990 to May 1997 pelvic percutaneous biopsies have been carried out with a CT Sytec 3000. From May 1997 to December 1999 the device was replaced by a High Speed CTi. The introduction of spiral CT allowed reduction of performance mean time from 45 minutes (standard deviation 15) to 30 minutes (standard deviation 10). RESULTS: In 154 patients (80%) we observed a neoplastic, inflammatory or not classified degeneration. In 8 patients (4%) the retrieved material ended to be inadequate for a diagnosis. In 31 patients (16%) no disease was revealed at the histological examination. Such patients with negative histological examination have been kept under clinical and radiological control in the following period in order to verify the manifestation or the presence of an alteration previously not observed. On 31-3-2000 none of them had been submitted to a new percutaneous biopsy of the pelvic region. The overall mean accuracy has been 96% considering the negative patients as really negative. In 5 cases (2.6%) we have had complications represented by pain at the introduction and penetration site of the needle. DISCUSSION AND CONCLUSIONS: The choice of the needle, the approach to the lesion and the position of the patient are conditioned by the site of the tumor, its extension, the distance skin-neoplastic disease and by the respect of the incision lines of Enneking, in order not to complicate the job of the orthopaedic surgeon spreading tumoral cells outside the chosen surgical approach. The mean time of the procedure is 30 minutes (standard deviation 10). There are no absolute contraindications to percutaneous biopsy except the suspect or the presence of an hydatideal cyst. The risks have to be compared with those correlated with alternative methods or with the more concerning risk of a missed diagnosis. Complications in the literature range from 0% to 10%, the incidence varying according to the location; pain is the most frequent complication. Altogether the most negative event, although not a true complication, is the retrieval of an inadequate sample: the only drawback of percutaneous biopsy in comparison with incisional biopsy. The accuracy rate of percutaneous biopsy varies in relation to the involved anatomical region, to the pathological process, to the experience of the user, to the amount of the retrieved tissue and to the cooperation of the patient. Our experience shows that, in selected patients, percutaneous biopsy is a virtually safe and almost painless procedure which saves the patient from a surgical procedure in regional or general anestesia as for an incisional biopsy, and allows immediate planning and scheduling of a correct therapy for primitive or secondary neoplastic lesions.

[Computerized tomography assessment of femoral and tibial rotation in total knee prosthesis]. / Valutazione con Tomografia Computerizzata della rotazione delle componenti femorale e tibiale nell'artroprotesi totale del ginocchio.

PURPOSE: CT assessment of the axial deviation of the femoral and tibial prosthetic components in total knee arthroplasty. MATERIAL AND METHODS: January to July 1999, seventeen patients, 10 males and 7 females, mean age 66 years (standard deviation +/- 4) were examined after total knee arthroplasty. Exclusion criteria were prosthesis loosening and severe (equal or superior to 7 degrees) varus or valgus deviation. All patients were examined with knee radiography in the standing position completed by axial projections of patella and by CT scanning. We used a modification of Berger technique and carried out comparative CT scans extended lower limbs and acquisitions perpendicular to the mechanical axis of the knee, from the femoral supracondylar region down to the plane crossing the distal end of the tibial prosthetic component. Reference lines were then drawn electronically on given scanning planes to reckon the axial deviation of the femoral and tibial prosthetic components. RESULTS: Six patients, one female and 5 males, with normal rotational values of femoral and tibial prosthetic components presented no clinical symptoms. Eight patients, 4 females and 4 males, with abnormal values presented the following clinical symptoms: medial impingement, (incomplete) dislocation patella, and lateral instability. One female patient with a normal rotational value of femoral prosthetic component and an altered value of tibial prosthetic component presented medial impingement. Finally two patients, one female and one male, were absolutely asymptomatic although the rotational values of the two prosthetic components were beyond the normal range. CONCLUSIONS: Total knee arthroplasty is presently a standard treatment for many conditions involving this joint. There are several possible postoperative complications, namely fractures, dislocations (a)septic loosening and femoropatellar instability. The latter condition is the most frequent complication among implant failures and is caused by bad orientation of the femoral and tibial components on frontal and axial planes. We measured the orientation of the prosthetic components introducing a CT procedure which modifies the uniarticular with four scans introduced by Berger. The new method uses Berger's parameters and the CT study of both joints by means of Helical CT. With a single examination lasting less than 4 minutes and with the patient in a more comfortable position, we can obtain: 1) comparative and simultaneous assessment of the contralateral joint; 2) several scans to better define Berger's parameters and to accomplish measurement of the rotational deviation with higher precision and markedly decreasing the error margin. The analysis of the results confirms the international literature findings and especially the fundamental importance in positioning both prosthetic components within normal values, as emphasized by the relationship between the clinical symptoms and the rotational degree of the femoral and tibial prosthetic components.

[Significance of computerized tomography in the diagnosis of post-traumatic proximal carpal instability]. / L'importanza della Tomografia Computerizzata nella diagnosi dell'instabilità carpale post-traumatica prossimale.

INTRODUCTION: Proximal carpal instability is a painful condition characterized by early or late loss of radioulnar joint (RUJ) congruence not affecting the normal bone alignment of the two carpal rows. The joint incongruence or (incomplete) dislocation which leads to proximal instability is caused by many traumatic and nontraumatic events. The diagnosis of (incomplete) dislocation of the distal RUJ may be extremely difficult to make at conventional radiography because such injuries can be seen only when the lateral joint projection is perfect; otherwise the diagnosis is not reliable. CT is the only imaging tool diagnosing the grade of distal RUJ congruence independent of the examination technique. MATERIAL AND METHODS: We studied the radiocarpal complex conditions leading to proximal instability at the Rizzoli Orthopedic Institute from December, 1995, through December, 1997. In all, 389 cases were seen, 376 from trauma and 13 of nontraumatic origin. Each injury was studied with conventional radiography, CT, and MRI. Radiography was performed in two projections, namely the posteroanterior one with hand extension and the lateral one with the forearm in neutral position and the elbow bent at 90 degrees; the projections were repeated whenever a cast brace was applied. Unenhanced CT was performed for comparison with the patient prone and the forearm and wrist in prone and neutral position, as well as with the patient, forearm and wrist supine. Three criteria of electronic image processing were adopted for the RUJ studies in the 3 projections: radioulnar lines, congruence, and epicenter. MRI was always performed after conventional radiography and CT. Only the involved radiocarpal region was studied; coronal, axial and sagittal images were acquired with T2-weighted GE and T1-weighted SE sequences. RESULTS: Proximal instability was found in 17 of 389 patients; it was early in 13 and late in 4 of them. The comparison of radiographic and CT results showed that the former method is unreliable, with 53% false negatives. Pain, a cast brace, congenital or acquired deformities of distal radius and ulna and patient mispositioning by the radiology technician can change the rotation of the forearm, wrist and hand and make a perfect laterolateral projection in neutral position unfeasible, which affects the radiographic diagnosis. Conversely, CT showed its extreme efficacy in assessing the distal RUJ congruence with no false negatives independent of the RUJ rotation and of instability type and grade. CONCLUSIONS: Conventional radiography is a poorly reliable tool for the diagnosis of joint incongruence and its grade. In contrast, CT can diagnose a RUJ (incomplete) dislocation easily and unquestionably, thanks to its axial capabilities, even when adequate radiographic studies would be unfeasible. If the anteroposterior projection of the radiocarpal complex shows a congenital or acquired deformity of distal radius, the lateral projection can be skipped and a CT scan in prone, neutral and supine position performed. The 3 CT criteria quantify incongruence type and grade, and also demonstrate the position of maximum incongruence and its decrease by position. The comparative study of the radiocarpal region makes CT a very useful and valuable tool in congenital instability because its allows the assessment of contralateral radioulnar congruence too. MRI is very useful in the diagnosis of injury or degeneration of the fibrocartilage complex, namely in patients with no bone changes at conventional radiography.

[Significance of three-compartment digitalized arthrography in the diagnosis of post-traumatic instability of the radiocarpal complex]. / L'importanza dell'artrografia tricompartimentale digitalizzata nella diagnosi dell'instabilità post-traumatica del complesso radio-carpico.

INTRODUCTION: The radiocarpal complex is the structure formed by the distal radioulnar, radiocarpal and midcarpal joints; these joints are compartments, each anatomically separated from the other. An appropriate arthrographic study with three-compartment injection better demonstrates the capsuloligamentous structures than conventional radiography. The diagnosis of any condition in this complex may therefore be easier to make. MATERIAL AND METHODS: From January 1993 to December 1996, twenty-six patients with mild to moderate wrist and carpal sprain and previously examined with radiography, were submitted to digital three-compartment arthrography at the Imaging Diagnostic Service of the Rizzoli Orthopedic Institute. Of 17 patients with previous radiographic diagnosis of scapholunar diastasis, 1 patient had a negative radiographic picture, 15 had an incomplete tear of the scapholunar ligament and 1 a double injury of the scapholunar and triquetro-lunar ligaments. Of 10 patients with mild to moderate triquetro-lunar diastasis, 8 had and arthrographic picture of pyramido-lunar ligament injury, 1 had a double injury of the triquetro-lunar and scapholunar ligaments and another one of triangular fibrocartilage complex injury. RESULTS: Three-compartment contrast agent injection permitted the diagnosis of interruptions between the different compartments and more injuries of scapholunar and triquetro-lunar ligaments than single compartment injection. We examined 27 patients with small arch injuries with three-compartment digital arthrography and found scapholunar diastasis in 17 (63%) and triquetro-lunar diastasis in 10 (37%). In the first group of 17 patients, three-compartment arthography demonstrated more scapholunar ligament injuries (13 cases) than single compartment injection; image subtraction, allowed by the digital technique, showed 2 injuries not visible otherwise. Injuries of the scapholunar and triquetro-lunar ligaments were demonstrated with and without digital subtraction. One patient had no ligament injury. In the other group of 10 patients, three-compartment arthrography showed more triquetro-lunar ligament injuries (6 cases) than single compartment injection; image subtraction demonstrated 2 injuries not visible otherwise in this group too. Injuries of the scapholunar and triquetro-lunar ligaments were demonstrated with and without digital subtraction. The injury of triangular fibrocartilage and contrast agent leak into soft tissues were shown in one patient with the injection of the distal radioulnar compartment alone, regardless of image subtraction. CONCLUSIONS: Arthrography, combined with conventional static and dynamic radiography, increases the detection rate of capsuloligament joint defects in the wrist-carpal complex. The three-compartment digital technique combines the advantages of fluoroscopic monitoring and videorecording and allows real time imaging of the contrast agent flow during injection in different compartments. Moreover, the digital technique permits the complete study of all joints in a single session, while image subtraction reveals even minimal ligament changes. This technique becomes therefore a fundamental tool for surgical planning.

[Traditional radiology in the assessment of posttraumatic carpal instability]. / La radiologia tradizionale nella valutazione dell'instabilità carpale post-traumatica.

INTRODUCTION: Carpal instability is a painful posttraumatic syndrome with early or late loss of the normal alignment of the carpal bones, which can be caused by a variety of injuries, from minor sprain to major fracture-dislocation of the carpal-wrist complex. If the trauma causing instability is a fracture, a severe dislocation or a fracture-dislocation, the radiographic diagnosis is not particularly difficult. The morphologic and dynamic complexity of the carpal region represents, instead, a major obstacle in the radiologic diagnosis of mild or moderate sprains because the morphologic alterations on standard static views are minimal or absent in these conditions. MATERIALS AND METHODS: We reviewed 214 injuries causing posttraumatic carpal instability including both the cases classified by the Data Analysis Center of the Istituto Ortopedico Rizzoli as carpal dislocations and fracture-dislocations from January, 1975, to July, 1996, and the more recent cases directly observed at our Casualty Clinic. In the former cases, we reviewed only the available images, while our patients were examined with comparative standard and under stress or dynamic views. RESULTS: Of 214 lesions causing posttraumatic carpal instability, 43 along the great arch were classified as severe because they were easily detectable on standard films and 171 along the small arch were classified as mild because slight/no abnormalities were detected on standard static views. Only dynamic imaging showed posttraumatic carpal instability demonstrating the integrity of the ligaments and of the carpal hinges, as well as gaps or asymmetry not detected on static views. CONCLUSIONS: We suggest the systematic use of dynamic imaging in the cases where static findings are negative or poor, in the patients with a painful wrist after an apparently minor sprain. Missed or delayed diagnoses are thus reduced, as well as the consequent joint incongruity and/or chronic subluxation which may severely impair these patients.

[Nonmetastatic osteosarcoma of the limbs treated with neoadjuvant chemotherapy: correlation of tumor volume evaluated by CT and prognosis]. / Osteosarcoma non-metastatico delle estremità trattato con chemioterapia neoadjuvante: correlazione fra volume del tumore valutato mediante TC e prognosi.

A relationship between tumor volume and prognosis has been demonstrated in extraosseaous solid tumors, soft tissue tumors and Ewing's sarcoma. Fifty-five osteosarcoma patients, treated according to IOR-OS/NEO 3 protocol, have been studied in an attempt to verify if tumor volume is also a significant prognostic factor for the osteosarcoma of the extremities. Tumor volume was measured by CT-Scan. A trend towards a better prognosis for smaller tumors was observed, but no statistically significant differences were demonstrated according to the tumor size in the population studied. The authors conclude that for patients with osteosarcoma of the extremities, tumor volume can not be considered an adequate prognostic factor on the basis of which to tailor the chemotherapy treatment, as been recently proposed by other authors.

Modern diagnostic imaging of lumbar spondylosis.

The authors retrospectively analyzed 205 patients affected with low back pain and submitted to conventional radiology, CT scan, MR. The purpose of the study was that of gaining a better understanding of the mechanisms caused by the occurrence of spondylosis and its evolution. In light of the most recent literature, the authors conclude: 1) the degenerative process nearly always initiates with laceration of the anulus; 2) dysfunction of the disc then has repercussions on the posterior structures at varying times and with different modalities; 3) symptoms do not always coincide with radiological findings. Thus, the authors believe that for a more complete understanding of the etiopathogenesis and the evolution of spondylosis, further studies involving long-term follow-up of a young population, in relation to clinical and MR findings are needed. MR is the method of choice in determining disc degeneration.