Magnetic resonance imaging of anterior cruciate ligament rupture

BACKGROUND: Magnetic resonance (MR) imaging is a useful diagnostic tool for the assessment of knee joint injury. Anterior cruciate ligament repair is a commonly performed orthopaedic procedure. This paper examines the concordance between MR imaging and arthroscopic findings. METHODS: Between February, 1996 and February, 1998, 48 patients who underwent magnetic resonance (MR) imaging of the knee were reported to have complete tears of the anterior cruciate ligament (ACL). Of the 48 patients, 36 were male, and 12 female. The average age was 27 years (range: 15 to 45). Operative reconstruction using a patellar bone-tendon-bone autograft was arranged for each patient, and an arthroscopic examination was performed to confirm the diagnosis immediately prior to reconstructive surgery. RESULTS: In 16 of the 48 patients, reconstructive surgery was cancelled when incomplete lesions were noted during arthroscopy, making reconstructive surgery unnecessary. The remaining 32 patients were found to have complete tears of the ACL, and therefore underwent reconstructive surgery. Using arthroscopy as an independent, reliable reference standard for ACL tear diagnosis, the reliability of MR imaging was evaluated. The true positive rate for complete ACL tear diagnosis with MR imaging was 67%, making the possibility of a false-positive report of "complete ACL tear" inevitable with MR imaging. CONCLUSIONS: Since conservative treatment is sufficient for incomplete ACL tears, the decision to undertake ACL reconstruction should not be based on MR findings alone

Protocol requirements and diagnostic value of PET/MR imaging for liver metastasis detection

PURPOSE: To compare the accuracy of PET/MR imaging with that of FDG PET/CT and to determine the MR sequences necessary for the detection of liver metastasis using a trimodality PET/CT/MR set-up. METHODS: Included in this single-centre IRB-approved study were 55 patients (22 women, age 61 ± 11 years) with suspected liver metastases from gastrointestinal cancer. Imaging using a trimodality PET/CT/MR set-up (time-of-flight PET/CT and 3-T whole-body MR imager) comprised PET, low-dose CT, contrast-enhanced (CE) CT of the abdomen, and MR with T1-W/T2-W, diffusion-weighted (DWI), and dynamic CE imaging. Two readers evaluated the following image sets for liver metastasis: PET/CT (set A), PET/CECT (B), PET/MR including T1-W/T2-W (C), T1-W/T2-W with either DWI (D) or CE imaging (E), and a combination (F). The accuracy of each image set was determined by receiver-operating characteristic analysis using image set B as the standard of reference. RESULTS: Of 120 liver lesions in 21/55 patients (38 %), 79 (66 %) were considered malignant, and 63/79 (80 %) showed abnormal FDG uptake. Accuracies were 0.937 (95 % CI 89.5 - 97.9 %) for image set A, 1.00 (95 % CI 99.9 - 100.0 %) for set C, 0.998 (95 % CI 99.4 - 100.0 %) for set D, 0.997 (95 % CI 99.3 - 100.0 %) for set E, and 0.995 (95 % CI 99.0 - 100.0 %) for set F. Differences were significant for image sets D - F (P < 0.05) when including lesions without abnormal FDG uptake. As shown by follow-up imaging after 50 - 177 days, the use of image sets D and both sets E and F led to the detection of metastases in one and three patients, respectively, and further metastases in the contralateral lobe in two patients negative on PET/CECT (P = 0.06). CONCLUSION: PET/MR imaging with T1-W/T2-W sequences results in similar diagnostic accuracy for the detection of liver metastases to PET/CECT. To significantly improve the characterization of liver lesions, we recommend the use of dynamic CE imaging sequences. PET/MR imaging has a diagnostic impact on clinical decision making

Imaging in resectable colorectal liver metastasis patients with or without preoperative chemotherapy: results of the PROMETEO-01 study

BACKGROUND: The aim of the PROMETEO-01 Study was to define the diagnostic accuracy of imaging techniques in colorectal cancer liver metastasis (CRCLM) patients. METHODS: Patients referred to Bologna S. Orsola-Malpighi Hospital performed a computed-tomography scan (CT), magnetic resonance (MR), 18F-FDG-PET/CTscan (PET/CT) and liver contrast-enhanced-ultrasound (CEUS); CEUS was also performed intraoperatively (i-CEUS). Every pathological lesion was compared with imaging data. RESULTS: From December 2007 to August 2010, 84 patients were enrolled. A total of 51 (60.71%) resected patients were eligible for analysis. In the lesion-by-lesion analysis 175 resected lesions were evaluated: 67(38.3%) belonged to upfront resected patients (group-A) and 108 (61.7%) to chemotherapy-pretreated patients (group-B). In all patients the sensitivity of MR proved better than CT (91% vs 82%; P=0.002), CEUS (91 vs 81%; P=0.008) and PET/CT (91% vs 60%; P=0.000), whereas PET/CT showed the lowest sensitivity. In group-A the sensitivity of i-CEUS, MR, CT, CEUS and PET/CT was 98%, 94%, 91%, 84% and 78%, respectively. In group-B the i-CEUS proved equivalent in sensitivity to MR (95% and 90%, respectively, P=0.227) and both were significantly more sensitive than other procedures. The CT sensitivity in group-B was lower than in group-A (77% vs 91%, P=0.024). CONCLUSIONS: A thoraco-abdominal CT provides an adequate baseline evaluation and guides judgment as to the resectability of CRCLM patients. In the subset of candidates for induction chemotherapy to increase the chance of liver resection, the most rational approach is to add MR for the staging and restaging of CRCLM