Positive Magnetic Resonance Imaging Results Research Articles

Transsphenoidal surgery for Cushing disease: results of our experience in 39 consecutive patients

To evaluate magnetic resonance imaging (MRI) characteristics and surgical results of adrenocorticotropin (ACTH)-secreting pituitary adenomas.MRI characteristics and relationship between MRI positive rate and surgical results of 266 patients with pathologically confirmed Cushing's disease were analyzed retrospectively. All patients underwent thin-section sagittal and coronal scans of the pituitary gland before and after administration of gadolinium-diethylene triamine pentaacetic acid (Gd-DTPA) on a 1.5 Tesla MRI scanner, and dynamic enhanced MRI was performed in 39 patients. All patients underwent transsphenoidal adenomectomy. Endocrinological examinations and assessments were performed.Preoperative MRI revealed normal results in 41 (15.4%) cases, microadenoma in 179 (67.3%), macroadenoma in 42 (15.8%), and huge adenoma in 4 (1.5%). Pituitary apoplexy was found in 13 (4.9%) cases. Positive rate of ACTH-secreting adenomas was 84.6% (225/266) on MRI scans, and that of small microadenomas was 87.2% (34/39) on dynamic enhanced MRI scans. Preoperative endocrinological tests of 199 cases supported the diagnosis of typical Cushing's disease, while the other 67 cases had atypical endocrinological results. The endocrinological cure rate, remission rate, and inefficacy rate were 85.7%, 7.9%, and 6.4%, respectively. There was no difference in the initial endocrinological cure rate between the patients with positive and normal MRI results (90% vs. 87.8%, P = 0.904).Enhanced coronal pituitary MRI is helpful for preoperative localization of ACTH-secreting pituitary microadenoma. Dynamic enhanced MRI may improve detection rate of microadenoma. There is no marked difference in the surgical results for patients with preoperative MRI results indicating presence or absence of microadenoma.

Selective Nerve Root Injections Can Predict Surgical Outcome For Lumbar and Cervical Radiculopathy

Diagnostic selective nerve root injection (SNI) results were analyzed in 101 patients who underwent lumbar or cervical decompression for radiculopathy and compared to surgical outcome 1 year postoperatively. A comparison of surgical outcomes was also examined between magnetic resonance imaging (MRI) and SNI results. Of the 101 patients, 91 (90%) had positive and 10 had negative SNI results at the level operated. Ninety-one percent of the patients with a positive SNI had good surgical outcomes, whereas 60% of the patients with a negative SNI had good outcomes. Of the patients with a positive MRI result, 87% had good surgical outcomes, whereas a similar percentage of the patients with a negative MRI (85%) had good surgical outcomes. When findings between SNI and MRI differed (n = 20), surgery at a level consistent with the SNI was more strongly associated with a good surgical outcome. Of the patients with a poor surgical outcome, surgery was most often performed at a level inconsistent with the SNI finding. Our study found that a diagnostic SNI can safely and accurately discern the presence or absence of cervical or lumbar radiculopathy. The diagnostic SNI can persuade surgeons from operating on an initially suspicious, but incorrect, level of radiculopathy. In cases where MRI findings are equivocal, multilevel, and/or do not agree with the patient's symptoms, the result of a negative diagnostic SNI (ie, lack of presence of radiculopathy) becomes superior in predicting the absence of an offending lesion.

Pituitary magnetic resonance imaging findings do not influence surgical outcome in adrenocorticotropin-secreting microadenomas.

The pituitary origin of ACTH secretion in ACTH-dependent hypercortisolism can be difficult to assess, as magnetic resonance imaging (MRI) frequently fails to identify ACTH-secreting microadenomas or, on the contrary, may give false positive images of microadenomas. The choice of therapeutic option for patients with such normal MRI findings is controversial. Some groups propose routinely pituitary surgery, whereas others consider that neurosurgical exploration may be less successful and more harmful, and therefore prefer other types of management. The aim of this study was to compare surgical outcomes between patients with Cushing's disease (CD) and normal vs. positive pituitary MRI findings. Fifty-four patients (44 women and 10 men) with CD, operated on after 1996 in two centers (Kremlin-Bicêtre and Bordeaux) and followed postoperatively during a mean period of 19.9 +/- 22.7 months (range, 1-89 months), were enrolled in this retrospective study. Twenty-eight patients had normal pituitary MRI findings, and the pituitary origin of ACTH was established by bilateral petrosal sinus sampling in all of these cases. Twenty-six patients had positive MRI findings clearly showing a microadenoma. The two groups were not significantly different in terms of the sex ratio, age, frequency of hypertension, or diabetes, basal 24-h urinary free cortisol levels and follow-up. All of the patients were operated on by two experienced neurosurgeons using the same surgical protocol. Selective adenomectomy was performed when a tumor was identified, and subtotal hypophysectomy was performed when the lesion was uncertain or when no tumor was found during surgical exploration. Respectively, 50% and 84% of patients with normal and positive MRI results underwent adenomectomy (P < 0.05). A pituitary adenoma (confirmed by pathological examination) was found at surgery in 53% and 88% of patients in the normal and positive MRI groups, respectively (P < 0.05). The early surgical success rate (combining patients with corticotropic deficiency and patients with eucortisolism) was similar in the normal and positive MRI groups (78% and 88%, respectively; P = 0.85). The recurrence rate was lower in the normal MRI group, but the difference did not reach statistical significance (9% vs. 30%; P = 0.07). The final remission rate at the last visit was similar in the normal and positive MRI groups (72% and 61%, respectively; P = 0.29). Postoperative complications were also similar: 10 patients (36%) with normal MRI and five patients (20%) with positive MRI had at least one postoperative complication (surgical and/or pituitary deficiency; P = 0.12). Thus, the outcome of pituitary surgery in CD appears to be similar regardless of whether pituitary MRI shows a microadenoma. We recommend neurosurgical pituitary exploration as the first-line treatment of CD, provided that the pituitary origin of ACTH secretion is confirmed by bilateral petrosal sinus sampling in patients with normal pituitary MRI findings.

The value of combined radionuclide and magnetic resonance imaging in the diagnosis and conservative management of minimal or localized osteomyelitis of the foot in diabetic patients

Early diagnosis of osteomyelitis is helpful for a successful conservative treatment. The value of bone scanning combined with granulocytes labeled with hexamethylpropylene amine oxime (HMPAO) granulocyte-Tc99m (GN) radionuclide imaging (combined [RI]) with magnetic resonance imaging (MRI) for the diagnosis of osteomyelitis was assessed in 24 diabetic patients with foot ulcers. Evidence of osteomyelitis was based on the presence of at least one of the following criteria: (1) clinical bone involvement, (2) radiological bone involvement, (3) both positive combined RI and MRI, and (4) evidence of clinical bone involvement during the follow-up period. Thirteen patients had osteomyelitis. Seven patients had clinical bone involvement (sensitivity, 54%), five had radiological bone involvement (sensitivity, 38%), and 10 had positive combined RI for osteomyelitis (sensitivity, 77%). MRI demonstrated a higher sensitivity (100%). The specificity for combined RI and MRI was 82%. These results lead to a new diagnostic strategy for the early detection of minimal or localized osteomyelitis to avoid amputations. MRI is most appropriate following a negative x-ray in determining whether to treat osteomyelitis, since a negative MRI result rules out osteomyelitis. Antibiotic therapy should be used in the case of a positive MRI result, but Charcot joint disease can lead to false-positive MRI results. In this case, combined RI should be performed.