Role of MRI Evaluation in Knee Injuries

Knee is a major weight bearing and largest joint that provides mobility and stability during physical activities as well as balance while standing. Due to its wide range of functions it is exposed to forces beyond its physiological range, and thus bone and soft tissue of knee are at risk of injuries. We wanted to study MRI appearances of cruciate ligaments and meniscal tears in cases of knee injuries and correlate the MRI findings of knee injury with clinical observations/other radiological investigations/ arthroscopic findings. We also wanted to evaluate the sensitivity, specificity, PPV, NPV and accuracy of MRI in detecting knee injuries taking arthroscopy as gold standard (wherever performed).METHODSThis prospective diagnostic descriptive study was conducted in the Department of Radiodiagnosis of Maharishi Markandeshwar Institute of Medical Sciences and Research, MMDU, Mullana, among 100 patients presenting with knee injuries referred to Department of Radiodiagnosis for MR imaging. MR scans were carried out on 1.5 tesla MR machine Achieva (by Phillips Medical System) and studies were performed with the sense extremity coil. Arthroscopic knee surgery was performed in 39 patients. MR findings were correlated with clinical and arthroscopic findings wherever possible.RESULTSMR diagnosis of 100 cases was as follows: in ACL tear 50%; PCL tear 19%; MCL tear 17%; LCL tear 16%; MM tear 49%; LM tear 31%; Sensitivity, specificity, NPV, PPV and accuracy of MRI in detecting the knee injuries taking arthroscopy as gold standard are as follows ACL- 100%, 90.9%, 100%, 96.5% and 97.4 %; lateral meniscus-100%, 94.5%, 100%, 50% and 94.8%; medial meniscus 90.4%, 66.7%, 85.7%, 76% and 79.5% respectively. Correlation between MRI and arthroscopic findings regarding presence and absence of posterior cruciate ligament tear was highest with sensitivity -100%, specificity- 94.5%, NPV- 100% and accuracy-94.8%, There were 6 false positives for meniscus tear on MR examinations accounting for low positive predictive value (72%) of MR examination. Posterior horn tears of menisci are likely to be missed on arthroscopy. Out of 6 false positive cases of meniscus tear, 4 were located predominately in the posterior horn and 2 in the anterior horn. Thus, acceptance of MRI findings as false positive is controversial.CONCLUSIONSMRI is a useful non-invasive modality having high diagnostic accuracy, sensitivity and negative predictive value making it a very reliable screening test for diagnosis of internal derangements of knee joint. Thus, MRI saves many knees from unnecessary arthroscopies.

Ultrasonographic Examination of Peripheral Nerves in Diabetic Peripheral Neuropathy.

Diabetes has been a major problem in India. Its slow growth is associated with many complications, most common being peripheral neuropathy. An easy and cheap investigation to diagnose the neuropathy may help in early diagnosis and decrease the economic burden on the society. The purpose of the study was to assess the usefulness of ultrasonography (USG) in the evaluation of diabetic peripheral neuropathy (DPN).METHODSFifty adult diabetic patients with clinically diagnosed DPN and 50 diabetics without DPN were included in the study. USG of the medial, ulnar, and common peroneal nerves was done. The mean cross-sectional area (CSA) of the involved nerves was measured in the two groups at identical positions. The CSA was compared between the two groups, and Student t-test was applied to assess statistical significance.RESULTSThe mean thickness of median nerve among diabetics without DPN was significantly less at 5 cms proximal to wrist (7.34 ± 1.24 vs 11.12 ± 1.56, p<0.0001); was significantly less at mid-forearm (6.84 ± 0.77 vs 10.36 ± 1.72, p<0.0001); and was significantly less at elbow (7.36 ± 0.75 vs 10.2 ± 1.64, p<0.0001). The mean thickness of ulnar nerve among diabetics without DPN was significantly less at wrist joint (6.98 ± 0.89 vs 8.44 ± 1.34, p<0.0001); and was significantly less behind medial epicondyle (7.44 ± 0.93 vs 9.36 ± 0.98, p<0.0001). The mean thickness of common peroneal nerve among diabetics without DPN was significantly less at neck of fibula (7.26 ± 1.34 vs 9.3 ± 1.67, P<0.0001); and the mean thickness of posterior tibial nerve was also significantly less at 5 cms above medial malleolus (7.06 ± 1.25 vs 9.16 ± 1.61, P<0.0001). There was a significant increase in the CSA of the median, ulnar, posterior tibial and common peroneal, in DPN patients as compared to diabetics without DPN (p<0.05).CONCLUSIONSUSG demonstrates a morphological change in patients with DPN in the form of an increase in CSAs, which was statistically significant. USG can objectively complement other diagnostic investigations such as nerve conduction studies. High resolution ultrasonography of peripheral nerves has the potential to become the investigation of first choice for the evaluation of DPN.

Megalencephalic Leukoencephalopathy with Subcortical Cysts.

Megalencephalic Leukoencephalopathy is a rare entity which was first described by Van Der Knaap et al in 1995.[1] It is a progressive neurodegenerative disorder characterized by slow progression of mental deterioration. Megalencephaly sets in early in the disease usually in first year and can be more than 4 standard deviation above the mean. Seizures are present in almost all the patients. [2] We present typical MRI findings in a case of megalencephalic leukodystrophy with sub-cortical cysts.Megalencephalic leukoencephalopathy with sub-cortical cysts is a rare entity that presents with macrocephaly and seizures. Mental deterioration is often mild with slow progression. Macrocephaly may be present at birth or develops in first year. Typical magnetic resonance imaging (MRI) findings help to clinch the diagnosis.

MDCT Findings in Focal Fat Infarction of Appendage of Falciform Ligament- An Unusual Cause of Epigastric Pain.

The pathophysiology and clinical course of focal fat infarction of appendage of falciform ligament is similar to other acute fat infarction abdominal conditions like omental infarction and epiploic appendagitis in that it presents with acute abdominal pain and responds well to conservative treatment. Importance of radiological diagnosis is to avoid unnecessary surgery.[1] Torsion and focal fat infarction of appendage of falciform ligament is an extremely rare condition which presents with acute abdomen. It can mimic other serious abdominal conditions which require urgent surgical intervention. It is important to be aware of its computed tomography (CT) findings so as to avoid unnecessary surgical intervention. We present CT findings in case of focal fat infarction of appendage of falciform ligament in a young male who presented with acute epigastric pain.

Ring like Enhancement in Dysembryoplastic Neuroepithelial Tumour (DNET)

DNET is a low grade cortical neoplasm which closely resembles cortical dysplasia on magnetic resonance imaging (MRI). It is usually non-enhancing but can show some enhancement on about one third of case. Rarely enhancement can be ring like and when the mass is large in size, it can cause considerable diagnostic problem from higher grade gliomas. However, age of the patient and associated features like calcification, lack of mass effect and long duration of symptoms should assist in reaching the correct diagnosis. Dysembryoplastic neuroepithelial tumour (DNET) is low grade cortical glioma which is most commonly seen in temporal lobe. It is usually a non-enhancing tumour but sometimes it can show enhancement and occasionally it can be ring like, which can cause diagnostic confusion with higher grade gliomas. We report a case of DNET which showed ring like enhancement of post contrast images.

Presacral Ancient Schwannoma in a Middle-Aged Man- A Rare Entity,

Schwannomas are benign tumours arising from neoplastic transformation of Schwann cells around the nerve fibres. Tumours situated deeply like in retroperitoneum or pelvis are usually asymptomatic and may not be detected. Such long standing tumours may undergo extensive degenerative changes giving rise to ancient schwannomas.[1] Ancient schwannoma is an uncommon variant of schwannomas characterized by extensive degenerative changes and hypocellular areas. Presacral ancient schwannomas are rare and most of the reported cases are in females. We describe computed tomography (CT) findings in a case of presacral ancient schwannoma in a 49 year old male patient.

Traumatic Mesenteric Tear with Right Adrenal Haematoma and Partial Thrombosis of Inferior Vena Cava- A Rare Association

Post-traumatic isolated mesenteric tear with associated small bowel gangrene is a rare event after blunt abdominal trauma and has been reported previously in literature. [1] Post-traumatic thrombosis of inferior vena cava (IVC) is a very rare event with only isolated case reported in literature. [2] We report a rare case of mesenteric tear with segmental small bowel infarction. There was also right adrenal gland haematoma with associated thrombosis of right adrenal vein, which was extending into inferior vena cava causing its partial thrombosis. Post blunt trauma focal mesenteric tear and segmental small bowel gangrene is a rare event. Posttraumatic right adrenal haematoma is well described in literature while traumatic inferior vena cava (IVC) thrombosis is exceedingly rare. We report a rare case showing association of focal mesenteric tear with segmental small bowel gangrene and associated right adrenal haematoma with adrenal vein haematoma extending into IVC causing its partial thrombosis. To the best of our knowledge, such unusual association has not been reported previously in literature.