MR observations of postraumatic osteolysis of the distal clavicle after traumatic separation of the acromioclavicular joint.

PURPOSE: The purpose of this work was to characterize the MR features of post-traumatic osteolysis of the distal clavicle in patients who have sustained a previous separation of the ipsilateral acromioclavicular (AC) joint. METHOD: We studied eight male patients (mean age 25 years) with intractable pain in the AC joint after sustaining a traumatic joint separation. With use of the Rockwood classification, the separations were classified as Type 1 in one patient, Type 2 in two patients, and Type 3 in five patients. The MR studies were evaluated for periarticular soft tissue swelling, cortical irregularity defined as thinning or absence of portions of the cortex in the acromial and clavicular articular surfaces, hypertrophic osseous changes, periostitis, bone marrow edema, periarticular cyst-like changes, and joint space widening exceeding 6 mm. Radiographs were evaluated independently of the MR studies. Osteolysis of the distal clavicle was confirmed pathologically in seven patients and with surgery in one patient. RESULTS: The incidence of osteolysis in patients who have had a previous AC joint separation was estimated to be approximately 6%. Observations on MRI included soft tissue swelling, bone marrow edema in the distal clavicle, and cortical irregularity associated with periarticular cyst-like erosions in eight patients, joint space widening in six patients, clavicular periostitis in three patients, and marrow edema in the cromion in five patients. Only one patient had osteophyte formation. Radiographic observations of periarticular soft tissue swelling, osteopenia of the distal clavicle, articular erosions, and joint space widening allowed diagnosis in only four patients prospectively. CONCLUSION: The MR features of posttraumatic osteolysis are characteristic of this process. We advocate the use of MRI in patients with chronic AC joint pain who have had a prior AC joint dislocation, particularly if follow-up radiographs are nonspecific, equivocal, or do not indicate the presence of secondary osteoarthritis.

Atypical findings of discordant bone scan and radiographs in transient osteoporosis of the hip: case report and review of the literature.

The authors report atypical findings of discordant bone scans and radiography seen in a patient with transient osteoporosis of the hip (TOH). Presented in the case of a 60-year-old man who had spontaneous onset of left hip pain which worsened for 2 months with weight-bearing on the affected side. Initial and follow-up radiographs of the let hip were normal. Bone scan demonstrated intense uptake of Tc-99m MDP in the affected femoral head and neck, corresponding to characteristics of abnormal signal intensity of TOH or transient bone marrow edema syndrome on MRI. This discordant pattern of bone scan and radiographs has rarely been reported in the literature. Its possible mechanism of causation and clinical implication in TOH, together with a review of the literature, are discussed in this report.

Complete dislocation of the knee: spectrum of associated soft-tissue injuries depicted by MR imaging.

OBJECTIVE: Complete knee dislocation is a rare injury. The purpose of this study was to evaluate the spectrum of injuries that are depicted by MR imaging in patients with a dislocation of the knee and to determine if there is any predictive factor that might indicate those patients who may be at risk for popliteal nerve injury. MATERIALS AND METHODS: A retrospective search for patients sustaining traumatic knee dislocations who had radiographs and an MR imaging examination of the knee as part of their initial evaluation was done at three level I trauma centers for the period between 1989 and 1993. Each MR examination was independently reviewed by three osteoradiologists for ligamentous, tendinous, meniscal, and osseous injuries. Equivocal diagnoses were decided by consensus. Only patients who underwent surgery were selected. MR imaging findings were confirmed at the time of surgery. Seventeen patients (15 men, two women; age range, 14-62 years; mean age, 29 years) were studied. Motor vehicle accident, fall from a height, a vehicle striking a pedestrian, and football injury were common mechanisms of injury. Posterior dislocation (seven patients) and anterior dislocation (five patients) were the most common injuries. RESULTS: At the time of surgery, all patients had complete tears of the anterior cruciate ligament, 15 had complete tears of the posterior cruciate ligament, nine had complete tears of the medial collateral ligament, and 12 had tears of the fibular collateral ligament (nine tore both the fibular collateral ligament and the biceps femoris tendon). Popliteal tendon tears occurred in eight patients (six complete, two partial). Of the six patients with complete tears of the popliteal tendon, five occurred at the musculotendinous junction; all were the result of either posterior or posterolateral dislocations. Four patients had injuries to the peroneal nerve; three of the four also had tears of the popliteal tendon. On MR imaging, the integrity of the anterior cruciate and lateral collateral ligaments was correctly depicted in all 17 patients; evaluation of the posterior cruciate ligament resulted in one false-positive and one false-negative diagnosis of a tear; evaluation of the medial collateral ligament resulted in one false-positive diagnosis of a tear; and one false-positive diagnosis of a tear occurred with evaluation of the popliteal tendon. CONCLUSION: Knee dislocations cause extensive disruption of the ligaments that stabilize the knee and the surrounding soft-tissue structures, including the popliteal artery. Nearly all will result in disruption of the cruciate ligments and, often, injury of the collateral ligaments. An injury to the popliteal tendon denotes a more severe injury. The mechanism of injury that results in a popliteal tendon tear may also increase the possibility of a peroneal nerve injury. Recognition of this pattern of injuries on MR imaging enables precautionary observation for ischemic changes of the foot to be instituted in patients that otherwise may not be considered at risk for acute vascular compromise.

Magnetic resonance imaging of the diabetic foot.

MR is useful in evaluating foot abnormalities in diabetic patients. MR offers superior spatial resolution over radionuclide bone scans and superior soft tissue contrast over CT and radiography. MR is able to localize and distinguish soft tissue abscesses from soft tissue edema. MR is sensitive at demonstrating the presence and extent of osteomyelitis.

[The right ventricle and pulmonary circulation in hypertensive patients]. / Il cuore destro e il circolo polmonare nell'iperteso.

Elevated blood pressure and vascular resistance in patients with systemic hypertension are paralleled by a proportional rise in pressure and resistance in the lesser circulation. It was hypothesized that increased systemic reaction to adrenergic stimulation is shared by the pulmonary vessels. Thus normotensive subjects and patients with primary hypertension were investigated during mental arithmetic and the cold pressor test. Both groups responded to both stimuli; during arithmetic pressure reaction was mediated through an increase of cardiac output, and during the cold pressor test through a predominant rise in systemic vascular resistance. The pressure changes were emphasized in the hypertensive population. Pressure in the pulmonary artery in normotensive subjects was not affected by cold and was slightly raised (systolic) during arithmetic. In hypertensive patients, on the other hand, systolic and diastolic pressures were consistently augmented by both tests, and pulmonary arteriolar resistance rose by 42% and 29% of control during the cold pressor test and arithmetic, respectively. Changes in resistance reflected neurally-mediated vasoconstriction but not variations in the passive relationship between pressure and flow, since during arithmetic, for a similar rise in flow the driving pressure across the lungs was steady in normotensive subjects and rose significantly in hypertensive patients. In these same patients pressure was augmented by cold test in the absence of substantial changes in flow. At baseline and during tests pulmonary wedge pressure, pleural pressure, arterial blood gases, and pH were similar in the two populations. The intravenous infusion of similar scalar doses of norepinephrine (the same mediator released during cold test) was not effective on the pulmonary vessels of normotensives and caused an obvious vasoconstriction in hypertensives.(ABSTRACT TRUNCATED AT 250 WORDS)