Classification, diagnostic imaging, and imaging characterization of a lumbar herniated disk

The absence of universal nomenclature standardization with respect to the definition of a disk herniation and its different categories, especially regarding type and location, is still a major problem that will only be overcome when major national or international scientific societies join efforts to support a particular scheme. Meanwhile, it is important to realize that the two models that are currently most used are based on a different [figure: see text] perspective. Trying to straddle the two by opposing, for instance, bulging disk and herniation is doomed to failure because this exercise defies formal logic. MR imaging is currently the most accurate noninvasive imaging modality to diagnose a disk herniation and to determine its exact location. The determination of some pathoanatomic characteristics of herniated disks (type and composition) may require the use of CT, diskography, or CT diskography.

Effect of the learning process on procedure times and radiation exposure for CT fluoroscopy-guided percutaneous biopsy procedures

PURPOSE

To assess if the learning process associated with computed tomography fluoroscopy (CTF) technology influences procedure and fluoroscopy times for percutaneous biopsy procedures.

MATERIALS AND METHODS

Prospective analysis of the initial 250 consecutive patients who underwent percutaneous biopsy with use of a CT scanner equipped with rapid image reconstruction and fluoroscopic capabilities in a 24-month period. All procedures were performed with both continuous and spot fluoroscopic technique, with typical radiation parameters of 50 mA, 120 kV, and a 10-mm-slice thickness. The procedures were all performed by a single experienced interventional radiologist to limit the variables of physician expertise, interventional materials used, and biopsy approach. The subject group was divided into five equal consecutive groups of 50 patients. In each subgroup, the authors recorded mean lesion size, success, and complication rates, as well as mean procedure and fluoroscopy times.

RESULTS

The five subgroups were similar patient populations as documented by the absence of statistically significant differences when comparing mean lesion size, procedure success, and complication rates (P > .05; ANOVA test). A statistically significant decrease in mean fluoroscopy (groups 1-5: 50.26 vs 45.24 vs 33.86 vs 32.68 vs 25.8 sec/patient) and mean procedure times (groups 1-5: 30.08 vs 27.9 vs 26.34 vs 25.6 vs 21.6 min/patient) was recorded between the patient subgroups (P < .0001; ANOVA test).

CONCLUSION

The learning process associated with CTF technology impacts procedure parameters by decreasing both mean procedure and fluoroscopy times, thereby increasing patient turnover and decreasing radiation exposure to the patient and the operator.

Value of CT fluoroscopy for percutaneous biopsy procedures

PURPOSE

To assess the clinical impact of computed tomographic (CT) fluoroscopy (CTF) with regard to procedure time and success rate for CT image-guided biopsy procedures.

MATERIALS AND METHODS

One hundred ninety consecutive patients referred to the same radiologist underwent biopsy procedures performed with use of a CT scanner equipped with fluoroscopic capabilities during a 15-month period. CTF procedures were performed predominantly by means of a continuous fluoroscopic technique, with typical exposure factors of 50 mA at 120 kV and a slice thickness of 10 mm. The total procedure time, fluoroscopy time, and complication and procedure success rates were documented prospectively in this group. A control group consisted of retrospective analysis of 93 consecutive patients who had undergone a classic CT-guided procedure performed by the same radiologist.

RESULTS

Procedure success rate was increased in the CTF group (93.7 versus 88.2%), although the difference was not statistically significant (P > .05: Fisher exact test). A statistically significant difference was noted when comparing mean procedure times (CTF, 27.56 minutes; range, 20-60 minutes versus control, 43.17 minutes; range, 35-80 minutes; P < .0001; Welch unpaired t test).

CONCLUSION

CT fluoroscopy facilitates CT-guided biopsy procedures by allowing visualization of the needle trajectory from skin entry to the target point, allowing procedures to be performed more rapidly and efficiently.

Differentiating lumbar disc protrusions, disc bulges, and discs with normal contour but abnormal signal intensity. Magnetic resonance imaging with discographic correlations

STUDY DESIGN

Independent evaluation by two observers of 132 lumbar discs in 45 patients with chronic low back pain investigated by both magnetic resonance imaging and discography.

OBJECTIVES

To assess some of the fundamental differences between lumbar disc protrusions, disc bulges, and discs with normal contour but abnormal signal intensity on T2-weighted magnetic resonance images.

SUMMARY OF BACKGROUND DATA

Moderate interobserver agreement has been reported when the morphologic terms normal, bulge, protrusion, and extrusion are used. The validity of this nomenclature remains unknown.

METHODS

Discs were evaluated on magnetic resonance images for central and peripheral signal characteristics, height, contour, and nerve root compression. Discograms were classified according to degrees of disc degeneration, disruption, and pain reproduction.

RESULTS

Loss of intervertebral height or abnormal signal intensity on magnetic resonance imagery was significantly associated with disc disruptions extending into or beyond the outer anulus on discograms. All 23 protrusions (100%) and 12 of 15 disc bulges (80%) were associated with Stage 2 or 3 anular disruptions and, in most instances, similar or exact reproduction of pain during disc injection. There was no significant difference between disc protrusions, disc bulges, and discs with normal contour but abnormal signal, with respect to degree of disc degeneration, extent of disruptions, or presence of discogenic pain.

CONCLUSIONS

In patients with chronic low back pain, loss of disc height or abnormal signal intensity is highly predictive of symptomatic tears extending into or beyond the outer anulus. Disc bulges and disc protrusions do not represent discs with significantly different internal architecture, based on the findings of discography, and are no more suggestive of symptomatic tears than discs showing normal contour but decreased height or abnormal signal intensity.

Increased blood manganese in cirrhotic patients: relationship to pallidal magnetic resonance signal hyperintensity and neurological symptoms

Increasing evidence suggests that manganese deposition is responsible for the T1-weighted magnetic resonance imaging (MRI) signal hyperintensity consistently observed in pallidum of cirrhotic patients. However, the relationship between blood manganese and the etiology or severity of liver disease, as well as the neurological symptomatology in these patients, has not been well established. In the present study, blood manganese concentrations were measured by atomic absorption spectrometry together with MRI and neurological evaluation in 57 cirrhotic patients with various etiologies and severity of liver disease. Blood manganese concentrations were elevated in 67% of cirrhotic patients and were significantly higher in patients with previous portacaval anastomoses or transjugular intrahepatic portosystemic shunt (TIPS). Pallidal signal hyperintensity was observed in 88% of patients, and significant correlations were demonstrated between blood manganese and pallidal index (PI) (a measure of pallidal signal hyperintensity), as well as Child-Pugh score. Assessment of extrapyramidal symptoms using the Columbia rating scale revealed a significant incidence of tremor, rigidity, or akinesia in up to 89% of cirrhotic patients. However, there was no significant correlation between blood manganese and extrapyramidal symptoms, although severity of akinesia was significantly greater in Child-Pugh C patients. Extrapyramidal symptoms could result from a toxic effect of manganese on basal ganglia dopaminergic function. These findings further support a role for manganese in the etiology of pallidal MRI signal hyperintensity in patients with chronic liver disease.

Clinical impact of contrast-enhanced MR imaging reports in patients with previous lumbar disk surgery

OBJECTIVE

We wanted to assess the clinical impact of the reports of contrast-enhanced MR imaging on the decision to repeat surgery and on the results of repeat surgery in patients with previous lumbar disk surgery.

SUBJECTS AND METHODS

We interviewed 257 patients who had undergone lumbar disk surgery and who showed symptoms suggesting persistent or new disk herniation. We conducted our interviews 6-18 months after patients had undergone contrast-enhanced MR imaging. We then correlated patient outcome with original MR findings.

RESULTS

Fifty-two patients underwent new surgical procedures after their MR examination. Findings of disk herniation on MR images were associated with a significantly greater frequency of repeat surgery. The size of main herniation seen on MR images was also a significant variable. Patients with Worker's Compensation Insurance files had significantly worse prognoses: Only two (8%) of 26 of these patients reported 50% improvement 1 year after repeat surgery. However, only 6 (23%) of 26 non-Worker's Compensation patients reported 50% improvement 1 year after surgery.

CONCLUSION

Despite its documented high anatomic accuracy, the clinical usefulness of enhanced MR imaging for patients with previous lumbar disk surgery needs further evaluation. In our series, findings of disk herniations on enhanced MR examinations were associated with a greater frequency of repeat surgery, but such surgery relieved symptoms in few patients. The influence of enhanced MR imaging on the decision for repeat surgery and on the type of surgery may be misleading. Selection criteria for repeat surgery need to be reassessed using rigorous outcome research protocols.

Radiating pain to the lower extremities caused by lumbar disk rupture without spinal nerve root involvement

PURPOSE

To locate the origin of the pain during lumbar diskography by means of a limited intradiskal injection of a local anesthetic.

METHODS

Lumbar diskography by the direct central posterior approach was performed in 235 consecutive patients. In 17 patients, severe and persistent low back pain, with unilateral or bilateral radiation to the lower extremities, was provoked by contrast injection into only one disk. One milliliter of 1% lidocaine was then slowly injected in the center of these disks.

RESULTS

A 75% to 100% reduction of the low back pain was experienced by 13 patients, and a 75% to 100% reduction of the radiating pain was experienced by 16 patients within 60 seconds after the intradiskal injection of lidocaine. Radiographs demonstrated radial tears through the entire annulus thickness in 16 of 17 disks.

CONCLUSION

Our results suggest that, in some patients with low back pain and unilateral or bilateral radiation to the lower extremities, the pain arises from within the disk. In these cases, pain radiating to the lower limb seems to be a referred type and seems unrelated to direct nerve root compression or irritation by a disk fragment in the epidural space.

You drive me crazy: a case report of acute psychosis and neurocysticercosis

Cysticercosis is a parasitic disease endemic in several developing countries where people consume raw or insufficiently cooked pork. The authors present a clinical picture of an organic psychosis in a 24 year old female with CNS cysticercosis. The neuroradiologic follow-up of this patient pre and post treatment with praziquantel is presented. The implications of this case with regard to the pathophysiology of schizophrenia and schizophrenia-like psychoses is discussed.

A simplified terminology for abnormalities of the lumbar disk

The terminology for abnormalities of the lumbar disk has always been a source of confusion. Recent advances in pathological studies have inspired the authors to propose a simple classification of common disk anomalies suitable not only for diagnostic radiologists but also for referring clinicians. Although the diagnosis of a few pathological entities will only be possible with specific imaging techniques, the proposed classification is appropriate for reporting observations from plain films, conventional tomograms, myelograms, diskograms, computed tomography scans and magnetic resonance images. All lumbar disks can thus be classified into one or more of the following categories: normal, aging, scarred, ruptured and herniated. A disk herniation is defined as a localized exit of disk material beyond the limits of the original intervertebral space.

Comparison of high-resolution computed tomography with discography in the evaluation of lumbar disc herniations

After failure of conservative treatment, 100 patients with symptoms suggestive of lumbar herniated nucleus pulposus (HNP) but without objective deficits were investigated both by high-resolution CT (without intravenous or intrathecal contrast) and by discography. The L4-L5 and L5-S1 discs were investigated by both techniques in all patients. In addition, the L3-L4 disc was investigated in 20 patients. The 220 investigated discs were sorted out into 6 CT categories according to morphologic and technical criteria. They were also classified into 3 discographic groups according to morphologic and clinical criteria. Based on morphologic considerations alone, the false-negative CT rates varied from 0 to 64% and the false-positive rates varied from 0 to 19%, depending on the category under consideration. Based on both morphologic and clinical consideration, the false-negative CT rates varied from 34 to 57% and the false-positive CT rates varied from 23 to 50%. Thus, high-resolution CT does not constitute an adequate means of investigation for this category of patients and discography appears justified before considering any form of radical therapy.

Spinal cerebrospinal fluid leak demonstrated by radioisotopic cisternography

Many conditions are known to cause a cerebrospinal fluid (CSF) fistula; one of them is lumbar puncture for contrast myelography. Reported here is the case of a man who underwent contrast myelography at the L2-L3 level and who presented with postural headaches and lumbalgia with radiation to the legs three weeks after the procedure. Tc-99m albumin isotopic cisternography at the L5-S1 level was performed and clearly depicted a functional CSF leak through the dura at the L2-L3 level and CSF suffusion along several rachidian roots. Scinticisternography may thus be used to localize accurately a CSF leak.

Proportional localization system for anatomical interpretation of cerebral computed tomograms

The existence of individual variations in size and shape of the human brain constitutes a problem for the anatomical interpretation of brain reconstructed images obtained from scanning devices; it is, for example, responsible for most of the inaccuracies in reading CT scans. One way to account for these variations is to use a proportional localization system. In the 1960s a group of neurosurgeons developed such a system based on two pivotal intracerebral structures, the anterior and the posterior commissures; they published an atlas consisting of horizontal, coronal, and sagittal brain sections interpreted in the proportional system. The atlas also included standard proportional brain schemes based on anatomical and radiological studies on large numbers of individuals. In this article we report a target localization experiment that we carried out to determine if this atlas could be used as a reference for a more accurate interpretation of CT and, eventually, of positron emission tomography (PET) and nuclear magnetic resonance (NMR) scans. Ten radiopaque small targets were inserted through the skull in the cortex of three cadavers; head CT was performed, and the atlas was used for predicting the cortical location of the targets seen on the CT images: The predictions were confirmed. These results strongly support the use of the proportional atlas for the interpretation of CT as well as of PET and NMR scans.

Epidural blood patch for the treatment of chronic headache after myelography

Isotope studies have related chronic headache after myelography to persistent leakage of normal cerebrospinal fluid (CSF) through an unsealed puncture hole in the dura and arachnoid. Although a technique well known to anesthesiologists, the use of an epidural blood patch (EBP) as a means to seal the dural opening is not known to many radiologists. We have used this technique successfully in three patients and believe it should be performed on all those still suffering from typical postural headaches three weeks after myelography if conservative treatment has failed and if there are no contraindications.

A reappraisal of lumbar discography

Five hundred patients with negative or inconclusive pantopaque myelograms were investigated by lumbar discography. Discography remains the ideal complementary examination to demonstrate normal or diseased disc morphology and its findings were confirmed during surgery in 97.8% of explored discs. Discography is also a valuable clinical test since the injection may reproduce the patient's symptoms. Its observations were determinant in the surgeon's decision to explore a disc or not: 97.3% of patients submitted to laminectomy had an abnormal discogram and 73% of these patients experienced reproduction of clinical symptoms during the procedure. Myelography is superior to discography to demonstrate sequestered fragments, pachymeningitis and spinal stenosis, but was nevertheless not helpful in 56% of the patients in whom these diagnoses were made in the operating room.