Kalevi Soila

Magnetic Resonance Imaging During Healing of Surgically Repaired Achilles Tendon Ruptures

Twenty consecutive patients with 21 surgically re paired Achilles tendon ruptures were imaged with a 0.1-T magnet at 3 and 6 weeks, and at 3 and 6 months after surgery. Clinical follow-up examinations and func tional tests were performed at the time of scanning. An intratendinous area of high-intensity signal was ob served in 19 of the 21 surgically repaired Achilles tendons at 3 months after surgery on proton density- and T2-weighted images. The three patients with the largest lesions had clinically poor outcomes at 3 months, whereas those with smaller intratendinous le sions had normal recoveries. Furthermore, patients with an abnormal walk at 3 months (N = 5) had sta tistically larger intratendinous lesions than patients who could walk normally. In all patients the cross- sectional area of the rejoined Achilles tendon showed the largest increase after cast removal (between 6 weeks and 3 months after surgery). In all cases the largest tendon area was measured at 3 months after surgery. Magnetic resonance imaging provides a pre cise valuable tool to evaluate the postsurgical internal structure of the surgically repaired Achilles tendon.

Postoperative MR Imaging and Ultrasonography of Surgically Repaired Achilles Tendon Ruptures

Purpose: To evaluate and compare MR and US findings in an unselected group of patients with 1–3-year-old surgically repaired complete ruptures of the Achilles tendon. Material and Methods: Thirteen patients with complete Achilles tendon rupture underwent clinical, MR and US examinations. The average time interval from rupture to postoperative imaging was 18 months. Results: The cross-sectional area of a postoperative tendon was 4.2 times that of the unaffected side. The shape of the operated tendon was more rounded than the unaffected side and it had irregular margins both in MR imaging and in US examination. In 4 of 13 cases an intratendinous area of intermediate to high signal intensity on proton density- and T2- weighted images was seen on MR. The size of this area varied from 4 to 18% of the cross-sectional tendon area. Two patients with the largest intratendinous area had poor clinical outcome. On US the tendon had mixed echogenicity in all cases and the tendon bands were thinner and shorter than normal. Comparison of dimension between MR and US revealed that in a.p. dimension the correlation was good (r=0.87, p=0.001), but in transversal width there was no significant correlation (r=0.58, p=0.06). Conclusion: The increased size and round irregular area of the operated Achilles tendon rupture was well detected by both MR and US, but intratendinous lesions were seen only by MR.

MRI of anterior cruciate ligament repair with patellar and hamstring tendon autografts

Abstract Objective. Several MRI sequences were used to evaluate the 2-year postoperative appearance of asymptomatic knee with a torn anterior cruciate ligament (ACL) reconstructed with bone–patellar tendon–bone (BTB) and semitendinosus and gracilis (STG) tendon autografts. Design and patients. Two groups with successful repair of ACL tear with BTB (n=10) or STG (n=10) autografts were imaged at 1.5 T with sagittal and oblique coronal proton density-, T2-weighted and sagittal STIR sequences and plain and contrast-enhanced oblique coronal T1-weighted sequences. The appearance of the graft and periligamentous tissues was evaluated. Results. In all 20 cases, the ACL graft showed homogeneous, low signal intensity with periligamentous streaks of intermediate signal intensity on T2-weighted images. In 10 cases, localised areas of intermediate signal intensity were seen in the intra-articular segment of the graft on proton density- and T1-weighted images. The graft itself did not show enhancement in either of the two groups, but mild to moderate periligamentous enhancement was detected in 10 cases. Conclusion. The MRI appearance of ACL autograft is variable on proton density- and T1-weighted images. Periligamentous tissue showing contrast enhancement is a typical MRI finding after clinically successful ACL reconstruction.

Proton Relaxation Times in Arterial Wall and Atheromatous Lesions in Man

The proton relaxation times of autopsy samples of arterial intima-media were measured with an NMR spectrometer and results correlated to the microscopically estimated lipid content of the vascular wall. The normal arterial intima-media contained two T1 relaxation components. The short T1 component (T1s) was 90 +/- 13 ms and its relative weight was 11%. The long T1 component (T1l) was 523 +/- 89 ms and relative weight 88%, respectively. The average T2 was 99 +/- 18 ms. In diseased vessels, a positive correlation was found between the lipid content of the vessel wall and the relaxation rate of the fast component. T1s of the intima-media was significantly shorter (P less than .01) in severe atheromatosis compared with vessels without fat deposition. The results suggest that atheromatous lesions should be best highlighted in spin-echo images by using short TR and TE to suppress the influence of T1l and to avoid (noncontrast contributing) T2 decay of the signal intensity.

MRI assisted treatment planning for radiation therapy of the head and neck

Improved visualization of head and neck tumors has been demonstrated with the use of magnetic resonance imaging (MRI). Using standard plastic radiation therapy immobilization casts and an MR positive surface marker system developed in this institution, we have utilized MRI as an adjunct to the simulation of complex radiation treatments for tumors of the head and neck. This technique includes an indirect display of field margins and/or isodose curves over selected MR images. The lack of induced artifact from the immobilization cast, improved delineation of tumor extension from normal anatomy and the ability to image in arbitrary planes without changing patient positioning favor the use of MR over CT for radiation therapy planning in the head and neck, while ensuring reproducibility of the treatment plan at subsequent therapy sessions.

Demonstration of cavernomatous transformation of the portal vein by magnetic resonance imaging.

A case of cavernomatous transformation of the portal vein demonstrated by magnetic resonance (MR) imaging is reported. Correlative images on scintigraphy and ultrasound are included. As in other vascular abnormalities, MR imaging is capable of depicting the findings noninvasively.

Sensitivity of MRI in metastatic neoplasia: a case report

Serial magnetic resonance imaging (MRI) and computed tomography (CT) were performed on a patient with metastatic lung cancer to brain. Magnetic resonance (MR) visualized two foci of intracerebral metastasis six weeks prior to CT.